4EEE-09-10-1 sem

7. SUBJECT DETAILS

7.2 POWER SEMI CONDUCTOR DRIVES

7.2.1 Objectives and Relevance

7.2.2 Scope

7.2.3 Prerequisites

7.2.4 Syllabus

i. JNTU

ii. GATE

iii. IES

7.2.5 Suggested Books

7.2.6 Websites

7.2.7 Expert Details

7.2.8 Journals

7.2.9 Recent Findings and Developments

7.2.10 Session Plan

7.2.11 Tutorial Plan

7.2.12 Student Seminar Topics

7.2.13 Question Bank

i. JNTU

ii. GATE

iii. IES

7.2.1 OBJECTIVE AND RELEVANCE

The area of electric motor drives is a dependant discipline. It is an applied and multi disciplinary subject comprising electronics, machines, control, processors / computers, software, Electromagnetics and Engineering applications. With the advent of power electronics the control of machines was made easy and wide. As every industry aims at production with less economy and environmentally free from pollution, this power semi conductor control of drives is one which could satisfy the foresaid. So this subject really puts the thinking rails as the current trend of motor control is involved with both power electronics and micro controllers.

7.2.2 SCOPE

Power Electronics and motor drives constitute a complex and interdisciplinary subject. Which have gone through spectacular evolution in the last three decades. It is without any doubt that the power electronics will play a dominant role in the 21st century in industrial, commercial, residential, aerospace, utility and military applications with the emphasis for energy saving and solving environmental pollution problems.

7.2.3 PREREQUISITES

The students must have basic knowledge of the following subjects1. Power Electronics 2. Network Theory3. Basic electronics, semiconductors and their characteristics 4. Electrical Machines5. Control Systems

7.2.4.i SYLLABUS – JNTU

UNIT – I OBJECTIVE

This unit introduces the concept of Electrical drive and the control of separately excited DC shunt and series motors.

SYLLABUS

Introduction to Thyristor controlled drives, single phase semi and fully controlled converters connected to dc separately excited and dc series motors continuous current operation, output voltage and current waveforms, speed and torque expressions, speed, torque characteristics, problems on converter fed DC motors.

UNIT – II OBJECTIVE

This unit deals the control of separately excited dc shunt and series motor using 3-phase semi and full converter.

SYLLABUS

Three phase semi and fully controlled converters connected to DC separately excited and DC series motors, output voltage and current waveforms, speed and torque expressions, speed, torque characteristics, problems.

UNIT – III OBJECTIVE

This unit deals with four quadrant operation of drives by dual converters.

SYLLABUS

Introduction to four quadrant operation, motoring operation, electric braking, plugging, dynamic and regenerative braking operations, four quadrant operation of DC motor by dual converters, closed loop operation of DC motor (Block diagram only)

UNIT – IV OBJECTIVE

This unit deals with the control of DC motors using chopper.

SYLLABUS

Single quadrant, two-quadrant and four quadrant chopper fed DC separately excited and series excited motors, continuous current operation, output voltage and current waveforms, speed, torque expressions, speed torque characteristics, problems on Chopper fed DC motors, closed loop operation (Block diagram only).

UNIT – V OBJECTIVE

This unit covers the control of induction motor from stator side through AC voltage controller. Also emphasis on the variable voltage.

SYLLABUS

Variable frequency characteristics, control of induction motor by AC voltage controllers, waveforms, speed torque characteristics.

UNIT – VI OBJECTIVE

This unit deals with control of induction motor through stator side using VSI & CSI.

SYLLABUS

Variable frequency characteristics, variable frequency control of induction motor by voltage source and current source inverter and cyclo converters, PWM control, comparision of VSI and CSI operations, speed torque characteristics, numerical problems on induction motor drives (Block diagram only). UNIT – VII OBJECTIVE

This unit introduces the concept of slip power recovery scheme and discusses the various configuration of control of the induction moter from rotor side.

SYLLABUS

Static rotor resistance control, slip power recovery, static scherbius drive, static kramer drive, their performance and Speed-torque characteristics, advantages applications, problems.

UNIT – VIII OBJECTIVE

This unit introduces the concept of separate and self control of synchronous motor, discussing in detail the operation of self controlled synchronous motors by VSI, CSI and cycloconverters.

SYLLABUS

Separate control and self control of synchronous motors, operation of self controlled synchronous motors by VSI, CSI and cycloconverters, load commutated CSI fed synchronous motor, operation, waveforms, speed, torque characteristics, applications, advantages, numerical problems, closed loop operation of synchronous motor drives (Block diagram only).

7.2.4.ii SYLLABUS - GATE

UNIT-IBasics concepts of adjustable speed dc drives.

UNIT-IIBasics concepts of adjustable speed dc drives.

UNIT-IIIBasics concepts of adjustable speed ac drives.

UNIT-IVBasics concepts of adjustable speed ac drives.

UNIT-VBasics concepts of adjustable speed ac drives.

UNIT-VIBasics concepts of adjustable speed ac & dc drives

UNIT-VIIBasics concepts of adjustable speed ac & dc drives

UNIT-VIIIBasics concepts of adjustable speed ac & dc drives

7.2.4.iii SYLLABUS - IES

UNIT-IBasics concepts of adjustable speed dc drives.

UNIT-IIBasics concepts of adjustable speed dc drives.

UNIT-IIIBasics concepts of adjustable speed ac drives.

UNIT-IVBasics concepts of adjustable speed ac drives.

UNIT-VBasics concepts of adjustable speed ac drives.

UNIT-VIBasics concepts of adjustable speed ac & dc drives

UNIT-VIIBasics concepts of adjustable speed ac & dc drives

UNIT-VIIIBasics concepts of adjustable speed ac & dc drives

7.2.5 SUGGESTED BOOKS

TEXT BOOKS

T1 Fundamentals of Electrical Drives – G.K. Dubey, Narosa Publications.T2 Power Electronics – MD Singh and K.B. Khanchandani, Tata McGraw Hill Publishing Company,

1998.T3 Power Semi Conductor Drives by PV Rao, BS Publications.

REFERENCE BOOKS

R1 Power Semiconductor Controlled Drives – Gopal K. Dubey, PH International Publications.R2 Power Semiconductor Drives – S.B. Dewan, G.R. Selmon, A. Straughen.R3 Modern Power Electronics and AC Drives – B.K. Bose, Pearson education.R4 Thyristor control of Electric Drives – Vedam. Subramanyam, Tata McGraw Hill Publications.R5 Electric Drives – N.K. De and P.K. Sen, Prentice Hall of India Pvt. Ltd.R6 A First Course on Electrical Drives – S.K. Pillai, 2nd Edn., New Age International (P) Limited,

Publishers.R7 Analysis of Thyristor Power – Conditioned Motors – S.K. Pillai, University Press (Indii. Ltd., Orient

Longman Ltd., 1995.

7.2.6 WEBSITES

1. www.powerelectronics.com2. www.powerdesigns.com3. www.semikron.com4. www.cdpowerelectronics.com5. www.magnetekpower.com6. www.micro-power.com7. www.iitm.ac.in8. www.iitd.ac.in9. www.iitk.ac.in10. www.iitb.ac.in11. www.iitg.ernet.in12. www.iisc.ernet-in

7.2.7 EXPERT DETAILS

REGIONAL

1. Name : V.T. SomashekharDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering,

NIT-Warangal – 506004.Phone No. : +91-870-2453416 (O) Email : [email protected], [email protected]

2. Name : Dr. Bhagwan K.MurthyDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering,

NIT-Warangal – 506004.Phone No. : +91-870-2431616(O)Email : [email protected], [email protected]

3. Name : Dr. A.D.RajkumarDesignation : ProfessorDepartment : Electrical EngineeringOffice Address : Department of Electrical Engineering, University College of Engineering

Osmania University, Hyderabad-500007Phone No. : +91-040-27682382 (O)Email : [email protected]

NATIONAL

1. Name : D.P. KothariDesignation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering

Dy. Director (Administration.), IIT - Delhi, Hauzkhas, New Delhi - 110016.Phone No. : +91-11-26591250 (O) , Fax : 91-11-26862037,Email : [email protected], [email protected]

2. Name : Dr. S.V. Kulkarni,Designation : Associate Professor,Department : Electrical and Electronics EngineeringOffice address : IITBombay, Powai, Mumbai - 400076, India,Phone No. : +91- 22-25671098,Email : [email protected]

3. Name : Dr.J K Chatterjee Designation : Professor & Head of Department Department : Electrical and Electronics engineering

Office Address : Room No. II/211, IIT Delhi Phone No. : +91 11 2659 1094 ,91 11 2659 1886

Email : [email protected]

4. Name : Dr. Sivaji ChakravortiDesignation : Professor,Department : Electrical and Electronics engineering, Office Address : Jadavpur University, Kolkatta - 700032, IndiaPhone No. :Email : [email protected], [email protected]

INTERNATIONAL

1. Name : Gary S. MaryDesignation : Professor

Department : School of Electrical EngineeringOffice address : Georgia Institute of Technology, USA.Phone No. :Email : [email protected]

2. Name : Dr. Clayton R Paul, Designation : ProfessorDepartment : Electrical and Computer Engineering,Office Address : School of Engineering, Mercer University, Macom, Georgia-31207,Phone Number : (912) 301-2213,website : www.faculty.mercer.paul_cr

3. Name : Jushan ZhangDesignation : Associate Prof

Department : Dept. of Electrical EngineeringOffice address : Ira A.Fulton School of Engineering, Arizona State University. Tempe, AZPhone No. : 85287-7206Email : Jushan Zhang @ee.gatech.edu

4. Name : Dr. Edward Wai-Chau Lo, Designation : Honorary Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice address : Department of Electrical and Electronics Engineering,

University of Hongkong, Hongkong.Email : [email protected]

7.2.8 JOURNALS

1. Name of the Journal : IEEE Transactions on energy conversionPublisher : IEEE Publications

2. Name of the Journal : IEEE Transactions on power electronicsPublisher : IEEE Publications

3 Name of the Journal : IEEE Transactions on Industrial ElectronicsPublisher : IEEE Publications

4. Name of the Journal : IEEE Transactions on Industrial ApplicationsPublisher : IEEE Publications

5. Name of the Journal : IEEE Transactions on Automatic ControlPublisher : IEEE Publications

6. Name of the Journal : Electrical engineering update.Publisher : Institution of Engineers (India) Publishers

7. Name of the Journal : Electrical IndiaPublisher : Chary Publications Pvt Ltd.

8. Name of the Journal : Journal of Institution of Engineers, India.Publisher : Institution of Engineers (India) Publishers

9. Name of the Journal : Elector-India ElectronicsPublisher : Century Publications Pvt Ltd

10. Name of the Journal : E-PowerPublisher : EFY Enterprises Pvt Ltd

11. Name of the Journal : Electrical EngineeringPublisher : Institution of Engineers (India) Publishers

7.2.9 RECENT FINDINGS AND DEVELOPMENTS

1. Title : An Interleaved AC–DC Converter Based on Current TrackingAuthor : Hwu, K. I.; Yau, Y. T.Journal : IEEE Transactions on Industrial electronicsYear, Vol. & page No. : May 2009,Volume: 56, Issue: 5, Page(s): 1456-1463

2. Title : One-Cycle-Controlled Bidirectional AC-to-DC Converter With Constant Power Factor

Author : Ghodke, D. V.; E. S., E. S.; Chatterjee, K.; Fernandes, B. G.Journal : IEEE Transactions on Industrial electronicsYear, Vol. & page No. : May 2009,Volume: 56, Issue: 5, Page(s): 1499-1510

3. Title : Based on Direct Thrust Control for Linear Synchronous Motor Systems

Author : Sung, C.-C.; Huang, Y.-S.Journal : IEEE Transactions on Industrial electronicsYear, Vol. & page No. : May 2009,Volume: 56, Issue: 5, Page(s): 1629-1639

4. Title : Buck–Boost Current-Source Inverters With Diode-Inductor Network

Author : Feng Gao; Chao Liang; Poh Chiang Loh; Blaabjerg, F.Journal : IEEE Transactions on Industrial electronicsYear, Vol. & page No. : May 2009,Volume: 56, Issue: 5, Page(s): 794-804

5. Title : Sliding-Mode Sensorless Control of Direct-Drive PM Synchronous Motors for Washing Machine Applications

Author : Song Chi; Zheng Zhang; Longya XuJournal : IEEE Transactions on Industrial Applications Year, Vol. & page No. : March-april 2009,Volume: 45, Issue: 2, Page(s): 582-590

6. Title : A Near-State PWM Method With Reduced Switching Losses and Reduced Common-Mode Voltage for Three-Phase Voltage Source Inverters

Author : Un, E.; Hava, A.M.Journal : IEEE Transactions on Industrial Applications Year, Vol. & page No. : March-april 2009,Volume: 45, Issue: 2, Page(s): 782-793

http://ieeexplore.ieee.org/xpl/tocresult.jsp?isnumber=4897610&isYear=2009






7.2.10 SESSION PLAN

Sl.No.

Topics in JNTU Syllabus Modules and Sub ModulesLecture

No.Suggested Books Remarks

UNIT-I CONTROL OF DC MOTORS BY SINGLE PHASE CONVERTERS (No. of Lectures – 0)

1Introduction to Thyristor

Controlled Drives

Electrical Drives- An Introduction, advantages of electrical drives,Parts of electrical drives

L1T1-Ch1 (P:1-10)T3-Ch1 (P:1)R1-Ch1 (P:1-2)

Choice of electrical drives, status of dc and ac drives

L2

2

Single Phase semi and fully controlled converters and three

phase semi and fully controlled converters

connected to DC separately excited and DC series motorContinuous current operationOutput voltage and current

waveformsSpeed and Torque expressions Speed Torque characteristics,Problems on converter fed dc

motors

DC Motors and their performance – shunt and separately excited machines and series motor operation

L3

T1-Ch5 (P:67-75)T2-Ch12 (P:794-798)T3-Ch1(P:2-7)R1-Ch2 (P:35-44)R2-Ch5 (P:214-238)

Single phase fully controlled converter fed separately excited motor with output voltage, current waveforms in CCM and Speed torque characteristics

L4

T1-Ch5 (P:111-128)T2-Ch12 (P:804-835)T3-Ch1(P:8-36)R1-Ch3 (P:65-101)R2-Ch5 (P:214-238)R3-Ch3 (P:112-121)

Single phase fully controlled converter fed series motor with output voltage, current waveforms in CCM and Speed torque characteristics

L5

Single phase semi converter fed separately excited with output voltage, current waveforms and Speed torque characteristics

L6

Single phase semi converter fed series motor with output voltage, current waveforms and Speed torque characteristics

L7

Problems on converter fed dc motors

L8

UNIT-II CONTROL OF DC MOTORS BY THREE PHASE CONVERTERS (No. of Lectures – 0)

3 Three phase semi and fully controlled converters connected to DC separately excited and DC series motor Continuous current operation Output voltage and current waveforms Speed and Torque expressions

Three phase full converter fed separately excited with output voltage, current waveforms and Speed torque characteristics

L9

T1-Ch5 (P:127-129)T2-Ch12 (P:839-844)R1-Ch3 (P:102-139)R2-Ch5 (P:240-270)R3-Ch3 (P:1222-132)Three phase full converter fed

series motor with output voltage, current waveforms and Speed torque characteristics

L10

Speed Torque characteristics,

Problems

Three phase semi converter fed separately excited and series motor with output voltage, current waveforms and Speed torque characteristics

L11

Three phase semi converter fed separately excited with output voltage, current waveforms and Speed torque characteristics

L12

Problems on converter fed separately excited

L13

Problems on converter fed series motor

L14

UNIT-III FOUR QUANDRANT OPERATION OF DC DRIVES (No. of Lectures – 0)

Introduction to Four quadrant operation Motoring operationElectric brakingPlugging, dynamic and regenerative braking operations

Multi quadrant operation and speed torque conventionsFour quadrant operation of a motor driving hoist load

L15

T1-Ch2 (P:14-15)T2-Ch12 (P:798-809)T3-Ch3 (P:69)R1-Ch1 (P:16-20)

Plugging operation L16 T1-Ch5 (P:77-84)T2-Ch12 (P:798-804)T3-Ch3 (P:70-89)R1-Ch2 (P:45-51)

Dynamic and Regenerative braking operations

L17

6Four quadrant operation of DC motor by Dual converters

Operation of dual converter in circulating mode

L18T1-Ch5 (P:130-132)T2-Ch8 (P:513-533)T3-Ch3 (P:91-99)R1-Ch5 (P:197-200)R2-Ch5 (P:271-273)

Operation of dual converter in non circulating mode

L19

7

Closed loop operation of DC motor (Block diagram only)

One quadrant closed loop speed control – current limit control, inner current control loop

L20T1-Ch3 (P:40-43)T2-Ch12 (P:845-850)T3-Ch3 (P:100-102)R1-Ch5 (P:184-189)

Closed loop armature control with field weakening

L21

UNIT-IV CONTROL OF DC MOTOR BY CHOPPERS (No. of Lectures – 0)

8

Single quadrantTwo-quadrant and four quadrant chopper fed DC separately excited and series excited motorsContinuous current operation Output voltage and current waveformsSpeed torque expressionsSpeed torque characteristics

Single quadrant operation of chopper fed DC separately excited and series motor with output voltage, current and Speed torque characteristics Problems

L22L23

T1-Ch5 (P:135-144)T2-Ch6 (P:395-407) Ch12 (P:845-849)T3-Ch4 (P:109-115)R1-Ch4 (P:146-166)R2-Ch6 (P:282-295)

Two quadrant operation of chopper fed DC separately excited and series motor with output voltage, current and Speed torque characteristics


Four quadrant operation of L25

chopper fed DC separately excited and series motor with output voltage, current and Speed torque characteristics

9Problems on Chopper fed DC motors

Problems on Chopper fed DC motors


Problems on Chopper fed DC motors

L27

10Closed loop operation (Block

diagram only).Closed loop operation with chopper

L28T2-Ch12 (P:845-849)R1-Ch5 (P:184-185)

UNIT-V CONTROL OF INDUCTION MOTOR THROUGH STATOR VOLTAGE (No. of Lectures – 0)

9

Variable voltage characteristicsControl of Induction Motor by AC Voltage controllers Waveforms Speed torque characteristics

Equivalent circuit of 3 phase induction motorsSpeed torque characteristics

L29

T1-Ch6 (P:152-160)T2-Ch13 (P:884-893)T3-Ch5 (P:151-156)R1-Ch6 (P:203-212)R2-Ch4 (P:155-156)R3-Ch2 (P:29-37)

Pole changing method stator voltage control3 phase ac voltage controller circuits performance analysisVariable terminal voltage controlProblems

L29L30

T1-Ch6 (P:152-160)T2-Ch13 (P:895-899)T3-Ch5 (P:157-165)R1-Ch6 (P:273-281)R2-Ch4 (P:156-198)

UNIT-VI CONTROL OF INDUCTION MOTOR THROUGH STATOR FREQUENCY (No. of Lectures – 0)

10 Variable frequency characteristics, Variable frequency control of Induction motor by Voltage Source, Current Source inverters and cyclo converters PWM controlSpeed-torque characteristics

Variable frequency controlOperation below rated frequency

L31T1-Ch6 (P:199-204)T2-Ch13 (P:899-907)T3-Ch6 (P:178-181)R1-Ch6 (P:283-313)

IES,GATEE

Operation above rated frequency L32

Control of induction motor by VSI

L32

T1-Ch6 (P:199-204)R1-Ch8 (P:283-313)R2-Ch7 (P:400-403)R3-Ch5 (P:191-205)

Operation of VSI6 step VSI fed IM, waveform performance analysis

L33T2-Ch13 (P:907-909)T3-Ch6 (P:183-192)

Control of induction motor by CSI


Operation of CSI L35

Control of induction motor by Cycloconverter

L36 T1-Ch6 (P:205-211)T2-Ch13 (P:923-924)T3-Ch6 (P:198-200)R2-Ch8 (P:468-500)

Control of induction motor by PWM inverter L37 T2-Ch13 (P:909-923)

R1-Ch8 (P:328-344)R2-Ch7 (P:406-408)R3-Ch5 (P:210-236)

PWM TechniquesSinusoidal PWM, Principle and operations

L38

11Comparison of VSI and CSI operations

Comparison of VSI and CSI operations

L39 R3-Ch6 (P:303-304)

12Closed loop operation of induction motor drives (Block diagram only)

Closed loop VSI controller Block Diagram approach with explanation of each block

L40T2-Ch13 (P:907-910)R1-Ch8 (P:313-319)R3-Ch8

Closed loop CSI controller Block diagram Approach with explanation of each block

L41

13Numerical problems on Induction motor drives

Problems on variable voltage control

L42 T1-Ch6 (P:206-211)T2-Ch13 (P:976-1000)R1-Ch8 (P:311-313)

Problems on variable frequency control

L43

UNIT-VII CONTROL OF INDUCTION MOTOR FROM ROTOR SIDE (No. of Lectures – 0)

14 Static rotor resistance control

Control of IM from rotor side-introduction, RRC, advantages, disadvantages, applicationsStatic rotor resistance control

L44


IES,GATE

15

Slip power recovery Static Scherbius Drive Static Kramer Drive Their performance and Speed-torque characteristics,

advantages Applications

Slip power recovery scheme-principleStatic Scherbius Drive-

L45

performance, speed torque characteristics,

L46

Power factor considerationsAdvantages and Applications

L47

Static Kramer Drive-performance, speed torque characteristics, advantages, applications

L48

T1-Ch6 (P:228-230)T2-Ch13 (P:939-944)T3-Ch7 (P:23-0232)R1-Ch9 (P:363-365)

16 Problems

Problems on Static rotor resistance control


Problems on static scherbius drive

L50

UNIT-VIII – CONTROL OF SYNCHRONOUS MOTORS (No. of Lectures – 08)

17 Separate control and Self control of Synchronous motors

Synchronous Motor OperationSeparate control of synchronous motor

L51 T1-Ch7 (P:251-267)T2-Ch13 (P:944-956)T3-Ch8 (P:262-263)

IES,GATE

18Operation of self controlled synchronous motors by VSI, CSI and Cycloconverters.

Operation of self controlled synchronous motor by VSI

L52 T2-Ch13 (P:961-965)T3-Ch13 (P:26)R1-Ch11 (P:464-467)

Operation of self controlled synchronous motor by CSI

L53

Operation of self controlled synchronous motor by Cyclo converter

L54T1-Ch7 (P:272)T3-Ch8 (P:276-277)

19

Load commutated CSI fed Synchronous motor Operation Waveforms Speed-torque Characteristics, Applications Advantages

CSI with load commutation-operation, waveforms and applications

L55T1-Ch7 (P:268-272)T3-Ch8 (P:269-275)R1-Ch11 (P:424-427)

Analysis of commutation and inverter operationSpeed torque characteristicsMerits and demerits of load commutation

L56

20 Numerical problems Numerical problems L57T1-Ch7 (P:266-271)T2-Ch13 (P:976-1000)

21Closed loop operation of synchronous motor drives (Block diagram only)

Closed loop operation of synchronous motor drives

L58T1-Ch7 (P:264-266)R1-Ch11 (P:424-427)

7.2.12 STUDENT SEMINAR TOPICS

1. Title : Control of Single Phase to Three Phase AC /DC/AC PWM Converters for Induction Motor Drives

Author : D.C. Lee and Y.S. KimJournal : IEEE Transactions on Industrial ElectronicsYear, Vol. & page No. : March-april 2007,Volume: 54, Issue: 2, Page(s): 797-804

2. Title : A Combination of Hexagonal and 12-Sided Polygonal Voltage Space Vector PWM Control for IM Drives Using Cascaded Two-Level Inverters

Author : Das. A.; Sivakumar K.; Ramchand. R.; Patel C.; Gopakumar.KJournal : IEEE Transactions on Industrial ElectronicsYear, Vol. & page No. : May 2009,Volume: 56, Issue: 5, Page(s): 1657-1664

3. Title : A Dual Seven-Level Inverter Supply for an Open-End Winding Induction Motor Drive

Author : Mondal, G.; Sivakumar, K.; Ramchand, R.; Gopakumar, K.; Levi, EJournal : IEEE Transactions on Industrial ElectronicsYear, Vol. & page No. : May 2009,Volume: 56, Issue: 5, Page(s):1665-1673

4. Title : Propulsion Drive Models for Full Electric Marine Propulsion Systems




Author : Apsley, J.M.; Gonzalez-Villasenor, A.; Barnes, M.; Smith, A.C.; Williamson, S.; Schuddebeurs, J.D.; Norman, P.J.; Booth, C.D.; Burt, G.M.; McDonald, J.R.

Journal : IEEE Transactions on Industry Applications Year, Vol. & page No. : March-April 2009,Volume: 45, Issue: 2, Page(s): 676-684

5. Title : Digital Implementation of Stator and Rotor Flux-Linkage Observers and a Stator-Current Observer for Deadbeat Direct Torque Control of Induction Machines

Author : West N.T.; Lorenz R.D.Journal : IEEE Transactions on Industry Applications Year, Vol. & page No. : March-April 2009,Volume: 45, Issue: 2, Page(s): 729-736

6. Title : Flux and Voltage Calculations of Induction Motors Supplied by Low- and High-Frequency Currents

Author : Consoli, A.; Bottiglieri, G.; Scarcella, G.; Scelba, G.Journal : IEEE Transactions on Industry Applications Year, Vol. & page No. : March-April 2009,Volume: 45, Issue: 2, Page(s): 737-746




7.2.13 QUESTION BANK

UNIT-I

1. Explain the concept of electric drives? Illustrate your answer with examples. (JNTU May 09)

2. Explain in detail the operation of a full- converter feeding a D.C series motor with reference to voltage and current waveforms, Assuming that the motor current is a continuous one. (JNTU May 09)

3. Draw and Explain the Speed-torque Characteristics at different firing angles for a full converter feeding a separately excited D.C motor. (JNTU May 09)

4. Derive the Speed, Torque Equations of a semi controlled converter connected to D.C series motor with continuous current operation with necessary waveforms. (JNTU May 09)

5. a. Explain the concept of constant torque control and constant power control. b. Explain how the speed control of a dc motor is achieved illustrating the triggering circuits of the

thyristors. (JNTU May 09)

6. Two independent single-phase semi-converters are supplying the armature and field circuits of the separately excited dc motor for controlling its speed. The firing angle of the converter, supplying the field, adjusted such that maximum field current flows. The machine parameters are: armature resistance of 0.25Ω , field circuit resistance of 147 Ω , motor voltage constant Kv=0.7032 V/A-rad/s. The load torque is T=45 N-m at 1000 rpm. The converter are fed from a 208 V, 50 Hz ac supply. The friction and windage losses are neglected. The inductance of the filed and armature circuits are sufficient enough to make the armature and field currents continuous and ripple free. Determine

a. the field current,b. the delay angle of the armature converter,c. input power factor of the armature circuit converter. (JNTU May 09)

7. a. Explain how the speed of a dc series motor is controlled using converters. (JNTU May 09)b. A series motor is supplied from a full converter whose α = 650, 1 φ supply of 230V rms, 50HZ

frequency. The armature and field resistance together equal 2Ω . The torque constant Maf is 0.23H and the load torque is 20Nm. Neglect damping and find the average armature current and speed.

8. a. Draw the circuit diagram and explain the operation of closed-loop speed control with inner-current loop and field weakening.b. A single phase fully controlled double bridge converter is operated from 120v, 60Hz supply and the

load resistance is 10 ohms. The circulating inductance is 40mH. Firing delay angle for converter I and II are 600 and 1200 respectively. Calculate the peak circulating current and the current through converters. (JNTU May 09)

9. a. What are the assumptions made while doing the steady-state performance of the converter fed dc drives. Justify your answers. (JNTU May 09)

b. Explain the use of freewheeling diode in the converter fed dc drives. Take an example of 1-phase fully controlled converter for explanation. How it is going to affect the machine performance?

10. a. What is the purpose of a free wheeling diode in converters when fed to DC motors.b. A 1 φ, half controlled converter is fed from a 120V rms, 60 HZ supply and provides a variable dc

voltage at the terminals of a dc motor. The thyristor is triggered continuously by a dc signal. The resistance of armature circuit is 10 Ω and because of fixed motor excitation and high inertia, the motor speed is considered constant so that the back emf is 60V. Find the average value of the armature current neglecting armature inductance. (JNTU Nov 08)

11. a. Explain how four-quadrant operation is achieved by dual converters each of 3 φ full wave configuration for d.c. separately excited motor. (JNTU Nov 08)

b. Distinguish between circulating current and non-circulating current mode of operation.

12. A single-phase fully controlled thyristor converter is supplying a dc separately excited dc motor. Draw the neat waveform diagrams and explain various operating modes of the drive both in motoring and regenerative braking for (a) γ < α, (b) γ > α,where α: is the firing angle, γ: is the angle at which the source voltage equal to the motor back emf. Assume the armature of the separately excited dc motor can be replaced by simple R-L and back emf load. (JNTU Nov 08)

13. A dc series motor has Ra = 3Ω , Rf = 3Ω and Maf = 0.15 H. The motor speed is varied by a phase-controlled bridge. The firing angle is П/4 and the average speed of the motor is 1450 rpm. The applied ac voltage to the bridge is 330 Sin wt. Assuming continuous motor current find the steady state average motor current and torque. Sketch the waveforms for output voltage, current and gating signals.

(JNTU Nov 08)

14. Explain the fundamentals of thyristor controlled drives and their operation. (JNTU Nov 08)

15. Draw and Explain Speed-torque characteristics of semi converter feeding a D.C series motor.(JNTU Nov 08)

16. Write down the basic performance equations for a D.C Series motor Sketch characteristics of constant torque drive and constant power drive regions. (JNTU Nov 08)

17. Derive the Speed, Torque Equations of a fully controlled converter connected to separately excited D.C motor with continuous current operation with necessary waveforms. (JNTU Nov 08)

18. Two independent single-phase semi-converters are supplying the armature and field circuits of the separately excited dc motor for controlling its speed. The firing angle of the converter, supplying the field, adjusted such that maximum field current flows. The machine parameters are: armature resistance of 0.25 ohm, field circuit resistance of 147 ohms, motor voltage constant Kv=0.7032 V/A-rad/s. The load torque is T=45 N-m at 1000 rpm. The converter are fed from a 208 V, 50 Hz ac supply. The friction and windage losses are neglected. The inductance of the filed and armature circuits are sufficient enough to make the armature and field currents continuous and ripple free. Determine

i. the field current,ii. the delay angle of the armature converter,iii. input power factor of the armature circuit converter. (JNTU Feb 08, May 05)

19. A single-phase fully controlled thyristor converter is supplying a dc separately ex-cited dc motor. Draw the neat waveform diagrams and explain various operating modes of the drive both in motoring and regenerative braking for

i. γ < α ,ii. γ > α,

Where α is the firing angle, γ is the angle at which the source voltage equal to the motor back emf. Assume the armature of the separately excited dc motor can be replaced by simple R-L and back emf load. (JNTU Feb 08, 07, Nov 06)

20. i. Explain the concept of constant torque control and constant power control.ii. Explain how the speed control of a dc motor is achieved illustrating the triggering circuits of the

thyristors. (JNTU Nov 07)

21. A dc series motor has Ra = 3Ω, Rf = 3 and Maf = 0.15 H. The motor speed is varied by a phase-controlled bridge. The firing angle is П/4 and the average speed of the motor is 1450 rpm. The applied ac voltage to the bridge is 330 Sin wt. Assuming continuous motor current find the steady state

average motor current and torque. Sketch the waveforms for output voltage, current and gating signals. (JNTU Nov 07, 05, May, Nov 04)

22. i. Explain how four-quadrant operation is achieved by dual converters each of 3-phase full wave configuration for D.C. separately excited motor. (JNTU Nov 07)

ii. Distinguish between circulating current and non-circulating current mode of operation.

23. Describe the relative merits and demerits of the following types of braking for dc motors: mechanical braking, dynamic braking and regenerative braking with neat diagram. (JNTU Feb 07, Nov 06)

24. i. What is 4-quadrant operation and explain with converters.ii. Give a simple circuit for the speed control of a dc separately excited motor.(JNTU Feb 07, Nov 06)

25. A 220v, 970 rpm, 100A dc separately excited motor has an armature resistance of 0.05. It is braked by plugging from an initial speed of 1000rpm. Calculate

i. Resistance to be placed in armature circuit to limit braking current to twice the full load value.ii. Braking torque andiii. Torque when the speed has fallen to zero. (JNTU Feb 07, Nov 06)

26. i. What is a dual converter? Explain the principle of operation of a dual converter in circulating current mode. How the same is used for speed control of dc drive.

ii. A 230v separately excited dc motor takes 50A at a speed of 800rpm. It has armature resistance of 0.4. This motor is controlled by a chopper with an input voltage of 230v and frequency of 500Hz. Assuming continuous condition throughout, calculate and plot speed-torque characteristics for:i. Motoring operation at duty ratios of 0.3 and 0.6.ii. Regenerative braking operation at duty ratios of 0.7 and 0.4. (JNTU Feb 07)

27. i. A DC shunt motor operating from a 1phase controlled bridge at a speed of 1450 rpm has an input voltage 330 Sin 314t and a back emf 75V. The SCRs are fired symmetrically at α = П/3 in every half cycle and the armature has a resistance of 5 W. Neglecting armature inductance, find the average armature current and the torque.

ii. Sketch the speed-torque characteristics for the above problem. (JNTU Feb 07, May 04)

28. i. What are the assumptions made while doing the steady-state performance of the converter fed DC drives. Justify your answers.

ii. Explain the use of freewheeling diode in the converter fed dc drives. Take an example of 1-phase fully controlled converter for explanation. How it is going to affect the machine performance?

(JNTU Feb 07, Nov 06, May 03)

29. i. Draw the circuit diagram and explain the operation of closed-loop speed control with inner-current loop and field weakening.

ii. A single phase fully controlled double bridge converter is operated from 120v, 60Hz supply and the load resistance is 10 ohms. The circulating inductance is 40mH. Firing delay angle for converter I and II are 60

0 and 120

0 respectively. Calculate the peak circulating current and the current through

converters. (JNTU Nov 06)

30. i. Explain how the speed of a dc series motor is controlled using converters.

ii. A series motor is supplied from a full converter whose p = 650, 1 phase supply of 230V rms, 50HZ frequency. The armature and field resistance together equal. The torque constant Maf is 0.23H and the load torque is 20Nm. Neglect damping and find the average armature current and speed.

(JNTU Nov 05)

31. A 220v, 750 rpm, 200A separately excited motor has an armature resistance of 0.05Ω. Armature is fed from a 3-phase non-circulating current mode dual converter, consisting of fully controlled rectifiers A and B. Rectifier A provides motoring operation in the forward direction and rectifier B in reverse direction. Line voltage of A.C. source is 400v. Calculate firing angle of rectifier for the motoring operation at rated torque and 600 rpm assuming continuous conduction. (JNTU May 05)

32. i. What is the purpose of a free wheeling diode in converters when fed to DC motors? ii. A 1phase, half controlled converter is fed from a 120V rms, 60 Hz supply and provides a variable dc

voltage at the terminals of a dc motor. The thyristor is triggered continuously by a dc signal. The resistance of armature circuit is 10 W and because of fixed motor excitation and high inertia, the motor speed is considered constant so that the back emf is 60V. Find the average value of the armature current neglecting armature inductance. (JNTU Nov 04, May 03)

33. i. Explain the concept of constant torque control and constant power control. ii. Explain how the speed control of a dc motor is achieved illustrating the triggering circuits of the

thyristors. (JNTU Nov 04, May 03)

34. Distinguish between circulating current and non-circulating current mode of operation.(JNTU May 04)

35. a. What are the assumptions made while doing the steady-state performance of the converter fed dc drives. Justify your answers.

b. Explain the use of freewheeling diode in the converter fed dc drives. Take an example of 1-phase fully controlled converter for explanation. How it is going to affect the machine performance?

(JNTU Nov 03)

36. a. What is the purpose of a free wheeling diode in converters when fed to DC motors.b. A 1 , half controlled converter is fed from a 120V rms, 60 HZ supply and provides a variable dc

voltage at the terminals of a dc motor. The thyristor is triggered continuously by a dc signal. The resistance of armature circuit is 10 and because of fixed motor excitation and high inertia, the motor speed is considered constant so that the back emf is 60V. Find the average value of the armature current neglecting armature inductance. (JNTU Nov 03)

37. i. Explain what is meant by constant torque and constant HP operation ii. What are the advantages and disadvantages of series converters? (JNTU May 03)

38. Derive an expression for the average output voltage of a semi converter assuming a very highly inductive load, and draw the waveforms of output voltage, load current and voltage across thyristors.

(JNTU May 03)

39. A 230 volts ,650 rpm,100 Amps separately excited DC motor has armature circuit resistance and inductance of 0.08 ohm and 8mH respectively .Motor is controlled by a rectifier with source voltage of 230V, 50 Hz. Identify the modes and calculate speeds for

i. α = 60o and torque =1000N-mii. α = 120o and torque =1000N-m (JNTU May 02)

40. i. A separately excited d.c motor is fed form a single phase fully controlled converter. Derive the expression for average speed for continuous current mode. Draw relevant waveforms

ii. Sketch the speed-torque characteristics for the above problem. (JNTU May 02)

41. Derive an expression for the average output voltage of a full converter and draw the waveforms of output voltage for a firing angle α. (JNTU May 02)

42. It is required to control the speed of a separately excited dc motor both in the forward and reverse direction by using suitable controlled rectifier automatically. With a block schematic, explain how the above object can be achieved? (JNTU May 01)

43. Show that the speed –torque characteristics of a DC series motor can be expressed in the form , where A and B are constants (JNTU May 01)

44. A DC battery is charged through a resistor R as shown in the figure

Derive an expression for the average charging current in terms of source voltage E, back e.m.f. Eb and resistance R. The SCR is fired continuously. If E = 220 V (r.m.s.) Eb = 100 (DIII. and R = 10 ohms, calculate i) Battery charging current; ii) Power supplied to the battery. (IES 01)

45. Explain how do you obtain modified speed-torque characteristics of D.C series motor.

46. Derive an expression for energy loss of separately excited D.C. motor under no-load.

47. Obtain speed-torque characteristics of three phase fully controlled converter fed separately excited d.c. motor.

48. i. Explain the function of sensing unit in an electric drive. ii. Draw speed torque characteristics of the following:

a. Traction load b. Constant power load.

49. What is the difference between active load and passive load.

50. Draw the circuit diagram to get no-load speed for a dc series motor.

51. Explain why the input power factor of a semi controlled dc curve is better than that of fully controlled drive.

52. Draw the block diagram of an electric drive and explain the dynamics of motor load combination.53. Explain the function of power modulator in electric drive.

54. Explain the torque equation of motor load combinationMatch the followinga) Full wave converter i) one-quadrantb) semi-converter ii) Two-quadrantsc) Dual-converter iii) Three-quadrants iv) Four-quadrants

55. Draw the speed –torque characteristics of differential compound motor.

56. What method of speed control of Dc motor leads to constant horse power operation?

57 A semi converter is not suitable for control of dc motor connected to active loads. Why?

58. .Draw the speed torque characteristics of a single phase fully controlled rectifier fed separately excited DC motor.

59. Discusses the advantages and disadvantages of thyristor controlled Dc drives.

60. Explain the speed control scheme for DC motor that uses a semi converter. What its limitations.

61. What are advantages of thyristor controlled drives? What are the hardware requirements for that?

62. A separately excited D.C motor is fed form a single phase fully controlled converter. Derive the expression for average speed for continuous current mode. Draw relevant waveforms A 230 volts, 650 rpm, 100 Amps separately excited D.C motor has armature circuit resistance and inductance of 0.08 ohm and 8mH respectively .Motor is controlled by a rectifier with source voltage of 230V, 50Hz. Identify the modes and calculate speeds for i. α=60

0 and torque =1000N-m

ii. α=1300 and torque =1000N-m

63. State and explain the important features of various braking methods of dc motors

64. A 230V, 870rpm, 100A separately excited dc motor has an armature resistance of 0.05 ohm. It is coupled to an overhauling load with a torque of 400 N-m. Determine the speed at which motor can hold the load by regenerative braking.

65. Explain why a dc motor is more suited to deal with torque over loads than other dc motors

UNIT – II

1. Derive the speed and torque expressions for a three phase semi controlled converter connected to a separately excited dc motor. (JNTU May 09)

2. Explain the basic operational aspects of three phase fully controlled converters with neat sketches of the waveforms and the circuit diagram. What is the effect of free wheeling diode. (JNTU May 09)

3. A 3Φ half wave bridge comprising three thyristors is fed from a 277rms , line to neural , 60Hz supply and provides an adjustable dc voltage at the terminals of a separately excited dc motor. The motor has Ra=0.02, La =.001H, Ka=1.2 and full load Ia = 500A. Find the firing angle so that the motor operates at full load current and at rated speed of 200rps. Assume continuous conduction and neglect thyristor forward voltage drop. (JNTU May 09)

4. Describe how the speed of a separately excited dc motor is controlled through the use of two 3- phase full converters. Discuss how two quadrant drive can be obtained from the scheme. Derive expressions for rms values of source and thyristor currents. State assumptions made. (JNTU May 09)

5. Describe the relative merits and demerits of the following types of braking for DC motors: mechanical braking, dynamic braking and regenerative braking with neat diagram. (JNTU Nov 08)

6. a. What is a dual converter? Explain the principle of operation of a dual converter in circulating current mode. How the same is used for speed control of dc drive.

b. A 230v separately excited dc motor takes 50A at a speed of 800rpm. It has armature resistance of 0.4 Ω. This motor is controlled by a chopper with an input voltage of 230v and frequency of 500Hz. Assuming continuous condition throughout, calculate and plot speed-torque characteristics for:i. Motoring operation at duty ratios of 0.3 and 0.6.ii. Regenerative braking operation at duty ratios of 0.7 and 0.4. (JNTU Nov 08)

7. a. Draw the circuit diagram and explain the operation of closed-loop speed control with inner-current loop and field weakening.b. A single phase fully controlled double bridge converter is operated from 120v, 60Hz supply and the

load resistance is 10 ohms. The circulating inductance is 40mH. Firing delay angle for converter I and II are 600 and 1200 respectively. Calculate the peak circulating current and the current through converters. (JNTU Nov 08)

8. Explain the Speed torque Characteristics of a dc series motor connected to a three phase fully controlled converter. (JNTU Feb 08)

9. Explain the Speed - torque Characteristics of a dc series motor connected to a three phase fully controlled converter.

10. The speed of a separately excited dc motor is controlled by means of a 3 phase semi converter from a 3 phase 415V 50Hz supply. The motor constants are inductance 10mH, resistance 0.9 ohm and armature constant 1.5v/rad/s.calculate speed of the motor at a torque of 50 Nm when the converter is fired at 45 0. Neglect losses in the converter.

11. Explain the Speed - torque Characteristics of a separately excited dc motor connected to a three phase semi controlled converter.

12. a. Explain the principle of closed-loop control of dc drive using suitable block diagram.b. A dual converter three phase bridge circuit supplied power to a 540V, 40A separately excited dc motor

with an armature resistance of 1.2. The voltage drops on the bridge thyristors are 12v at rated motor current. Power is supplied by an ideal three phase source with an rms line voltage 400v, 50Hz. Find the necessary firing, delay angle and motor back emf for:i. Motoring operation at rated load current with motor terminal voltage of 400v.ii. Regeneration operation at rated load current with terminal voltage of 400v.iii. Motor plugged at rated load current with a terminal voltage of 400v and a current limiting

resistor of 5 ohms (JNTU May 03)

13. a. What is 4-quadrant operation and explain with converters.b. Give a simple circuit for the speed control of a dc separately excited motor. (JNTU Nov 03)

14. A 3 phase full wave bridge comprising three thyristors is fed from a 277V rms, line to neutral, 60HZ supply and provides an adjustable dc voltage at the terminals of a separately excited dc motor. The motor specifications are Ra = 0.02 W, La = .001H, Ea = 1.2 wm and full load Ia = 500A. Find the firing angle so that the motor operates at full load current and at the rated speed of 200 rad/sec. Assume continuous conduction and neglect thyristor forward voltage drop. (JNTU May 04, 03)

15. i. Derive an expression for the average output voltage of a 3 phase full converter.ii. What is the frequency of the lowest order harmonic in the 3 phase full converters? (JNTU May 03)

16. Explain the operation of 3-phase semi converter with R load.

17. Obtain the voltage waveforms for α = 300, α = 60

0 and α = 90

0 for 3-Φ semi converter with R load.

18. Obtain the voltage waveforms for α = 150, α = 30

0 and α = 60

0 for 3-Φ semi converter with R, L and

E load.

19. What is the number of output pulses obtained in a 3- Φ semi converter when α < 600?

20. A 220 V, 1500 rpm, 50A separately excited motor with armature resistance of 0.5 ohms, is fed from a 3-phase fully-controlled rectifier. Available ac source has a line voltage of 440V, 50Hz. A star delta connected transformer is used to feed the armature so that motor terminal voltage equals rated voltage when converter firing angle is zero.

i. Calculate transformer turns ratio.ii. Determine the value of firing angle when :

a. motor is running at 1200 rpm and rated torque; b. when motor is running at - 800 rpm and twice the rated torque.

21. Obtain the output voltage and speed expression for a 3-phase semi converter.

22. Expression the operation of 3-phase full converter with R-Load.

23. Obtain the expression for output voltage, and speed for a 3-phase full converter.

24. Draw the waveform for motoring operation at = 300 and braking operation at = 1400 for 3-Φsemi converter with R load.

25. Distinguish between 3-phase semi converter and 3-phase full converter.

26. List the merits and demerits of 3-phase semi converter.

27. List the merits and demerits of 3-phase full converter.

28. Get the speed-torque curve for a 3-phase full converter fed DC separately excited DC motor.

29. Get the speed-torque curve for a 3-phase semi converter fed DC separately excited DC motor.

30. Explain the operation of 3-phase full converter fed DC series motor.

31. Explain the speed torque characteristics of m-phase full converter fed DC series motor.

32. A 220 V, 750 rpm, 200 A separately excited motor has armature and field resistances of 0.05 and 20 ohms respectively. Load torque is given by the expression TL = 500 - 0.2N N-m, where N is the speed in rpm. Speeds below rated value are obtained by armature voltage control with full field and the speeds above rated are obtained by field control at rated armature voltage. Armature is fed from a 3-phase fully controlled rectified with ac source voltage (line) of 170 V, 50 Hz and the field is fed from a half-controlled 1-phase rectified with a 1-phase source voltage of 250V, 50Hz. Drive operates under continuous conduction. Calculate firing angles for speeds. (a) 600 rpm, (b) 1200 rpm.

33. A 220V, 600 rpm, 500 A separately excited motor has armature and field resistances of 0.02 and 10 ohms respectively. Armature is fed from a 3-phase fully controlled rectifier and field from half controlled 1-phase rectifier. A three wire 3-phase AC source with a line voltage of 440V is available. Armature rectifier is fed from a 3-phase transformer with Y- connection and field rectifier from a 1-phase transformer.

i. Output voltages of transformers must be such that for zero firing angles rated voltages are maintained across the motor armature and field. Calculate transformer turns ratios.

ii. With the transformer turns ratios as in (i) calculate firing angles of the armature rectifier for: a. Rated torque and field, and 400 rpmb. Rated torque and field, and - 400 rpm. Assume continuous conduction.

34. A 220V, 750 rpm, 200A separately excited motor has an armature resistance of 0.05 ohms. Armature is fed from a 3-phase non-circulating dual converter consisting of fully controlled rectifiers A and B. Rectifier A provides motoring operation in the forward direction and rectifier B in reverse direction. Line voltage of AC source is 400V. Calculate firing angles of rectifiers for the following assuming continuous conduction.

i. Motoring operation at rated torque and 600 rpm.ii. Regenerative braking operation at rated torque and 600 rpm.

35. Motor problem 7.45 is now fed from a 3-phase dual converter with circulating current control. The AC source voltage is 400 V (line). When motor operates in forward motoring, converter A works as a rectifier and B as an inverter. Calculate firing angles of converters A and B for the following operating points.

i. Motoring operation at rated torque and 600 rpm.ii. Regenerative braking operation at rated torque and 600 rpm.

36. A fully controlled rectifier-fed separately excited DC motor is required to operate in motoring and braking operations in the forward direction. Only one fully controlled rectifier is available. What switching arrangement will be required ? Explain.

37. A fully controlled rectifier is feeding a separately excited motor driving a friction load. Motor is operating in steady-state with a rectifier firing angle of 30

0. Firing angle is now changed from 30

0 to

600. Explain how the motor current and speed will change with time.

UNIT – III

1. Explain briefly multi-quadrant operation of d.C Separately excited motor fed from fully controlled rectifier. (JNTU May 09)

2. a. Explain with circuit diagram, the speed control of separately excited D.C. motor using fully controlled single-phase bridge converter. Show how 2-quadrant of drive is made possible.

b. A 220 Volts, 960rpm, 13 Amps separately excited d.c. motor has armature resistance of 2 ohms. It is fed from a single-phase half controlled rectifier with an a.c. source of 230 volts, 50HZ. Assuming continuous conduction, calculate motor torque for α = 60o and speed 600 rpm (JNTU May 09)

3. a. With neat circuit diagram and waveforms, explain dynamic braking of separately excited motor by single phase converter.

b. A dc shunt motor has the armature resistance of 0.04 and the field winding resistance of 10. Motor is coupled to an over hauling load with a torque of 400N-m. Following magnetization curve was measured at 600 rpm:Field Current, A 2.5 5 7.5 10 12.5 1.5 17.5 20 22.5 25Back emf, V 25 50 73.5 90 102.5 110 116 121 125 129Calculate the value of RB when the motor is required to hold overhauling load at 1200rpm.

(JNTU May 09)

4. A 220V 200A, 800 rpm D.C Separately excited motor has an armature resistance of 0.06 ohms. The motor armature is fed from a variable source with an internal resistance of 0.04 ohms.

a. Calculate internal voltage of the variable voltage source when the motor is operating in regenerative breaking at 80% of the rated motor torque and 600 rpm.

b. If the motor is operated under dynamic breaking at twice the rated torque and 800 rpm then calculate the value of breaking current and resistor by assuming linear magnetic circuit. (JNTU May 09)

5. Describe the relative merits and demerits of the following types of braking for dc motors: mechanical braking, dynamic braking and regenerative braking with neat diagram. (JNTU May 09)

6. With a neat diagram, explain the operation of a dc drive in all four quadrants when fed by a single phase dual converter with necessary waveforms and characteristics. (JNTU May 09)

7. a. Deduce the mathematical expression for minimum and maximum currents for a class A chopper operated dc motor with back emf.

b. A 220v, 24A, 1000rpm separately excited dc motor having an armature resistance of 2Ω is controlled by a chopper. The chopping frequency is 500Hz and the input voltage is 230v. Calculate the duty ratio for a motor torque of 1.2 times rated torque at 500rpm. (JNTU Nov 08)

8. a. Explain with neat circuit diagram the basic principle of operation of a class A type of chopper. The chopper is connected to R-L-E load. Analyze the same for continuous current mode of operation.

b. A dc supply of 200v supplied power to separately excited dc motor via a class A thyristors chopper. The motor has an armature circuit resistance of 0.33 and inductance of 11mH. The chopper is fully on at the rated motor speed 1200rpm when the armature current is 20A. If the speed is to be reduced to 800rpm with the load torque constant, calculate the necessary duty cycle. If the chopper frequency is 500Hz, is the current continuous? (JNTU Nov 08)

9. a. List the advantages offered by dc chopper drives over line-commutated converter controlled dc drives.b. A dc chopper controls the speed of dc series motor. The armature resistance Ra = 0.04, field circuit

resistance Rf = 0.06, and back emf constant Kv =35 mV/rad/s. The dc input voltage of the chopper Vs=600v. If it is required to maintain a constant developed torque of T d = 547N-m, plot the motor speed against the duty cycle K of the chopper. (JNTU Nov 08)

10. a. Discuss with the suitable diagrams I quadrant and II quadrant choppers.b. A constant frequency TRC system is used for the speed control of dc series traction motor from 220v

dc supply. The motor is having armature and series field resistance of 0.025Ω and 0.015 Ω respectively. The average current in the circuit is 125A and the chopper frequency is 200Hz. Calculate the pulse width if the average value of back emf is 60 volts. (JNTU Nov 08)

11. Explain briefly the following methods of braking of a D.C Motora. Regenerative brakingb. Dynamic brakingc. Plugging.

12. a. Discuss in detail counter current and dynamic braking operations of D.C. shunt motors.b. A 400V, 750 rpm, 70A dc shunt motor has an armature resistance of 0.3 when running under rated

conditions, the motor is to be braked by plugging with armature current limited to 90A. What external resistance should be connected in series with the armature? Calculate the initial braking torque and its value when the speed has fallen to 300rpm.

13. What are the advantages of electric braking over mechanical braking of D.C. motors? Explain with proper circuit diagram Speed-Torque characteristics of D.C motor under dynamic braking, for the following types:a. Separately excited dc motor b. Series motor. (JNTU Nov 08)

14. a. With neat circuit diagram and waveforms, explain dynamic braking of separately excited motor by single phase converter. (JNTU Nov 08, 03)

b. A dc shunt motor has the armature resistance of 0.04 and the field winding resistance of 10. Motor is coupled to an over hauling load with a torque of 400N-m. Following magnetization curve was measured at 600 rpm:

Field Current (Amps.) 2.5 5 7.5 10 2.5 1.5 17.5 20 22.5 25

Back emf (Volts) 25 5. 73.5 9. 02.5 110 116 121 125 129

Calculate the value of RB when the motor is required to hold overhauling load at 1200rpm.

15. Describe the relative merits and demerits of the following types of braking for dc motors: mechanical braking, dynamic braking and regenerative braking with neat diagram. (JNTU Feb 08, Nov 07, 05)

16. i. Discuss in detail counter current and dynamic braking operations of D.C. shunt motors.ii. A 400v, 750 rpm, 70A dc shunt motor has an armature resistance of 0.3 ohms when running under

rated conditions, the motor is to be braked by plugging with armature current limited to 90A. What external resistance should be connected in series with the armature? Calculate the initial braking torque and its value when the speed has fallen to 300rpm. (JNTU Feb 08, Nov 04, May 03)

17. With a neat diagram, explain the operation of a dc drive in all four quadrants when fed by a single phase dual converter with necessary waveforms and characteristics.(JNTU Feb 08, May 04, Nov 03)

18. i. Draw the circuit diagram and explain the operation of closed-loop speed control with inner-current loop and field weakening.

ii. A single phase fully controlled double bridge converter is operated from 120v, 60Hz supply and the load resistance is 10 ohms. The circulating inductance is 40mH. Firing delay angle for converter I and II are 600 and 120

0 respectively. Calculate the peak circulating current and the current through

converters. (JNTU Nov 07, 05)

19. What is a dual converter? Explain the principle of operation of a dual converter in circulating current mode. How the same is used for speed control of dc drive.

20. Two independent single-phase semi-converters are supplying the armature and field circuits of the separately excited dc motor for controlling its speed. The firing angle of the converter, supplying the field, adjusted such that maximum field current flows. The machine parameters are: armature resistance of 0.25, field circuit resistance of 147 , motor voltage constant Kv=0.7032 V/A-rad/s. The load torque is T=45 N-m at 1000 rpm. The converter are fed from a 208 V, 50 Hz ac supply. The friction and windage losses are neglected. The inductance of the filed and armature circuits are sufficient enough to make the armature and field currents continuous and ripple free. Determine

i. the field current,ii. the delay angle of the armature converter,iii. input power factor of the armature circuit converter. (JNTU Nov 05)

21. i. Explain how four-quadrant operation is achieved by dual converters each of 3phase full wave configuration for D.C. separately excited motor.

ii. Distinguish between circulating current and non-circulating current mode of operation.(JNTU Nov 05, 04, May 03)

22. i. Explain the principle of closed-loop control of a dc drive using suitable block diagram.ii. Draw and explain the Torque-Speed characteristics for dynamic braking operation of dc series motor.

Why torque becomes zero at finite speed? (JNTU May 04, 02, Nov 03)

23. What are the advantages of electric braking over mechanical braking of D.C. motors? Explain with proper circuit diagram Speed-Torque characteristics of D.C motor under dynamic braking, for the following types:

i. Separately excited dc motor ii. Series motor (JNTU Nov 04, May 03)

24. i. Distinguish between dual converter with and without circulating current mode operation using proper circuit diagrams.

ii. A 220v, 750 rpm, 200A separately excited motor has an armature resistance of 0.05ohm. Armature is fed from a 3-phase non-circulating current mode dual converter, consisting of fully controlled rectifiers A and B. Rectifier A provides motoring operation in the forward direction and rectifier B in reverse direction. Line voltage of A.C. source is 400v. Calculate firing angle of rectifier for the motoring operation at rated torque and 600 rpm assuming continuous conduction. (JNTU May 04, 03)

25. A dual converter three phase bridge circuit supplies power to a 540v, 40A separately excited dc motor with an armature resistance of 1.2ohms. The voltage drops on the bridge thyristors are 12v at rated motor current. Power is supplied by an ideal three phase source with an rms line voltage 400v, 50Hz. Find the necessary firing, delay angle and motor back emf for:

i. Motoring operation at rated load current with motor terminal voltage of 400V.ii. Regeneration operation at rated load current with terminal voltage of 400V.iii. Motor plugged at rated load current with a terminal voltage of 400V and a current limiting resistor of 5

ohms. (JNTU May 04)

26. i. With neat circuit diagram and waveforms, explain dynamic braking of separately excited motor by single phase converter.

ii. A dc shunt motor has the armature resistance of 0.04ohm and the field winding resistance of 10ohm. Motor is coupled to an over hauling load with a torque of 400N-m. Following magnetization curve was measured at 600 rpm: Calculate the value of RB when the motor is required to hold overhauling load at1200rpm. (JNTU May 03)

27. i. What is 4-quadrant operation and explain with converters. ii. Give a simple circuit for the speed control of a dc separately excited motor. (JNTU May 03)

28. A 220v, 970 rpm, 100A dc separately excited motor has an armature resistance of 0.05ohm. It is braked by plugging from an initial speed of 1000rpm. Calculate

i. Resistance to be placed in armature circuit to limit braking current to twice the full load value.ii. Braking torque andiii. Torque when the speed has fallen to zero. (JNTU May 03)

29. Electrical braking of a dc series motor is not straight forward as that of a separately excited dc motors-Justify? (JNTU May 03)

30. What are the advantages of electric braking over mechanical braking of D.C. motors? Explain with proper circuit diagram Speed-Torque characteristics of D.C motor under dynamic braking, for the following types:a. Separately excited dc motor b. Series motor (JNTU Nov 03)

31. a. Discuss in detail counter current and dynamic braking operations of D.C. shunt motors.b. A 400v, 750 rpm, 70A dc shunt motor has an armature resistance of 0.3 when running under rated

conditions, the motor is to be braked by plugging with armature current limited to 90A. What external resistance should be connected in series with the armature? Calculate the initial braking torque and its value when the speed has fallen to 300rpm. (JNTU Nov 03)

32. a. Explain the concept of constant torque control and constant power control. b. Explain how the speed control of a dc motor is achieved illustrating the triggering circuits of the

thyristors. (JNTU Nov 03)

33. A 220v, 970 rpm, 100A dc separately excited motor has an armature resistance of 0.05. It is braked by plugging from an initial speed of 1000rpm. Calculate

i. Resistance to be placed in armature circuit to limit braking current to twice the full load value.ii. Braking torque andiii. Torque when the speed has fallen to zero. (JNTU Nov 03)

34. i. Explain the principle of closed-loop control scheme of dc drive using suitable block diagram.ii. Draw and explain the Torque-Speed characteristics for dynamic braking operation of dc series motor.

Why torque becomes zero at finite speed ? Explain. (JNTU May 02)

35. A 230v, 960 rpm, 200A separately excited motor has an armature resistance of 0.02W. Armature is fed from a 3-phase non-circulating current mode dual converter, consisting of fully controlled rectifiers A and B. Rectifier A provides motoring operation in the forward direction and rectifier B in reverse direction. Line voltage of A.C. source is 400v. Calculate firing angle of rectifier for the motoring operation at rated torque and 600 rpm assuming continuous conduction (JNTU May 02)

36. i. Discuss in detail counter current and dynamic braking operations of DC.ii. A 400v, 750 rpm, dc shunt motor has an armature resistance of 0.3ohms.when running under rated

conditions, the motor is to be braked by plugging with armature current limited to 90A.What external resistance should be connected in series with the armature ? Calculate the initial braking torque and its value when the speed has fallen to 300 rpm. (JNTU May 02)

37. Name the quadrants of multi-quadrant operation of drives.

38. Under what conditions regenerative braking occurs in 3-phase induction motor.

39. What are advantages of closed loop drive over open loop drive.

40. Write short notes on any twoi. Brushless dc motorii. Dynamic braking in a dc motor driveiii. Dual converter fed dc drive

41. What is rheostat braking?

42. What is duty ratio? And to what power electronic circuit it is related.

43. Name the converter circuit that makes the reversing operations in DC drives easier.

UNIT – IV

1. A 230V separately excited dc motor takes 50A at a speed of 800rpm. It has armature resistance of 0.4Ω. This motor is controlled by a chopper with an input voltage of 230V and frequency of 500Hz. Assuming continuous condition throughout, calculate and plot speed-torque characteristics for:

a. Motoring operation at duty ratios of 0.3 and 0.6.b. Regenerative braking operation at duty ratios of 0.7 and 0.4. (JNTU May 09)

2. A 220V, 70A D.C series motor has combined resistance of armature and field is 0.12 ohms running on no-load with the field winding connected to a separate source. It gave following magnetization characteristics at 600 rpm Field Current(A) 10 20 30 40 50 60 70 80Terminal Voltage (V) 64 118 150 170 184 194 202 210Motor is controlled in regenerative braking by a chopper with a source voltage of 220V.

a. Calculate motor speed for a duty ratio of 0.5 and motor breaking torque equal to rated motor torque.b. Calculate maximum allowable motor speed for a maximum permissible current of 70A and maximum

permissible duty ratio of 0.95.c. What resistance must be inserted in armature circuit for the drive to run at 1000 rpm without exceeding

armature current beyond 70 A? the duty ratio of the chopper has a range from 0.05 to 0.95.d. To What extent the number of turns in field winding should be reduced to run at 1000 rpm without

exceeding armature current beyond 70 A? (JNTU May 09)3. Distinguish between two quadrant and four quadrant drives.

4. What is a Chopper? Explain the Chopper control of a D.C series motor. a. Motoring Modeb. regenerative braking mode and also draw the Speed-Torque Curves in each mode.

5. a. Explain with neat circuit diagram the basic principle of operation of a class A type of chopper. The chopper is connected to R-L-E load. Analyze the same for continuous current mode of operation.

b. A dc supply of 200v supplied power to separately excited dc motor via a class A thyristors chopper. The motor has an armature circuit resistance of 0.33 and inductance of 11mH. The chopper is fully on at the rated motor speed 1200rpm when the armature current is 20A. If the speed is to be reduced to 800rpm with the load torque constant, calculate the necessary duty cycle. If the chopper frequency is 500Hz, is the current continuous? (JNTU May 09)

6. a. Derive the expressions for average motor current, current Imax and Imin and average torque for chopper-fed dc separately excited motor.

b. A dc chopper controls the speed of a separately excited motor. The armature resistance is Ra=0.05Ω. The back emf constant is Kv=1.527v/A-rad/s. The rated field current is If = 2.5A. The dc input voltage to the chopper is Vs= 600v. If it is required to maintain a constant developed torque of Td = 547N-m, plot the motor speed against the duty cycle k of the chopper. (JNTU May 09)

7. a. Explain why stator voltage control is suitable for speed control of Induction motors in fan and pump drives. Draw a neat circuit diagram for speed control of scheme of 3 phase Induction motor using AC Voltage Controller.

b. A 440V, 3 phase, 50 Hz 6 pole 945 RPM delta connected Induction Motor has the following parameter referred to the stator. RS = 2.0Ω Rr = 2.0Ω, XS = 3Ω, Xr = 4Ω. When driving a fan load at rated voltage it runs at rated speed. The motor speed is controlled by stator voltage control. Determine motor terminal voltage, current and torque at 800 RPM. (JNTU Nov 08)

8. A 440 V, 3-phase, 50 Hz, 6-pole 945 rpm, delta connected induction motor has following parameters referred to stator side: Rs = 2.0, Rr = 2.0, Xs = 3.0, Xr = 4.0. Rated voltage is impressed at the terminals for driving a fan load at rated speed. Stator voltage control employed to get variable speeds.

i. If the induction motor is running at 800 rpm, determine the motor terminal voltage, current flow into the stator and developed torque,

ii. What is the motor speed, current and torque if the terminal voltage is 280 V. (JNTU Nov 08)

9. a. Using 3 phase solid state AC Voltage Controllers explain clearly how it is possible to achieve 4 quadrant operation of 3 phase Induction motors.

b. Draw a closed loop block schematic diagram for the above speed control technique. Mention the merits of the above method of speed control. (JNTU Nov 08)

10. Explain the operation of four quadrant chopper fed to the D.C series motor and also draw the current and voltage wave forms for continuous current operation. (JNTU Nov 08)

11. a. Distinguish between class A and class B choppers with suitable examples of speed control of motors.b. A 220V, 190A dc series motor has armature and field resistance’s of 0.03 and 0.02 ohms respectively.

Running on no load as a generator with field wining connected to a separate source it gave following magnetization characteristic at 500rpm. (JNTU Nov 08)

Field Current : A 40 80 120 160 200Terminal Voltage : V 52 108 148 176 189

Motor is controlled by a chopper in dynamic braking with a braking resistance of 2.

i. Calculate motor speed for a duty ratio of 0.6 and motor current of 160A.ii. What will be the motor speed for a duty ratio of 0.75 and motor torque equal to half of rated

torque? (JNTU Nov 08)

12. a. Explain the principle of speed control of a dc motor and show how it can be achieved by a chopper.b. A 230V, 1200rpm, 15A separately excited motor has an armature resistance of 1.2. Motor is operated

under dynamic braking with chopper control. Braking resistance has a value of 20.i. Calculate duty ratio of chopper for motor speed of 1000rpm and braking torque equal to

1.5times rated motor torque.ii. What will be the motor speed for duty ratio of 0.5 and motor torque equal to its rated torque?

(JNTU Nov 08)13. A 220V, 70A D.C series motor has combined resistance of armature and field is 0.12 ohms running on

no-load with the field winding connected to a separate source. It gave following magnetization characteristics at 600 rpm

Field Current A 10 20 30 40 50 60 70 80Terminal Voltage V 64 118 150 170 184 194 202 210

Motor is controlled by a chopper with source voltage equal to 220V. Calculatea. Motor Speed for a duty ratio of 0.6 and motor current of 60Ab. Torque for a speed of 400 rpm and duty ratio of 0.65. (JNTU Nov 08)

14. i. Discuss with the suitable diagrams I quadrant and II quadrant choppers.ii. A constant frequency TRC system is used for the speed control of dc series traction motor from 220v

dc supply. The motor is having armature and series field resistance of 0.025ohms and 0.015ohms respectively. The average current in the circuit is 125A and the chopper frequency is 200Hz. Calculate the pulse width if the average value of back emf is 60 volts. (JNTU Feb 08, 07, Nov 06, May 03)

15. i. List the advantages offered by dc chopper drives over line-commutated converter controlled dc drives.ii. A dc chopper controls the speed of dc series motor. The armature resistance Ra = 0.04ohms, field

circuit resistance Rf = 0.06ohms, and back emf constant KV = 35 mV/rad/s. The dc input voltage of the chopper Vs=600v. If it is required to maintain a constant developed torque of Td = 547N-m, plot the motor speed against the duty cycle K of the chopper. (Feb 08, Nov 06, Nov, May 04, May 02)

16. i. A 230v, 960rpm and 200A separately excited dc motor has an armature resistance of 0.02 ohms. The motor is fed from a chopper, which is capable of providing both motoring and braking operations. The source has a voltage of 230v. Assuming continuous conduction:a. Calculate the time ratio of chopper for the motoring action at rated torque and 350 rpm.b. Determine the maximum possible speed if maximum value of time ratio is 0.95 and maximum permissible motor current is twice the rated value.

ii. Draw the necessary waveforms for the above problem. (JNTU Feb 08, May 04, 03)

17. i. Deduce the mathematical expression for minimum and maximum currents for a class A chopper operated dc motor with back emf.

ii. A 220v, 24A, 1000rpm separately excited dc motor having an armature resistance of 2ohms is controlled by a chopper. The chopping frequency is 500Hz and the input voltage is 230v. Calculate the duty ratio for a motor torque of 1.2 times rated torque at 500rpm.

(JNTU Feb 08, 07, Nov 05, 04, May 03)18. i. Derive the expressions for average motor current, current Imax and Imin and average torque for chopper-

fed dc separately excited motor.ii. A dc chopper controls the speed of a separately excited motor. The armature resistance is

Ra=0.05ohms. The back emf constant is Kv=1.527v/A-rad/s. The rated field current is If = 2.5A. The dc

input voltage to the chopper is Vs=600v. If it is required to maintain a constant developed torque of T d

= 547N-m, plot the motor speed against the duty cycle k of the chopper.(JNTU Nov, Feb 07, Nov, May 04, 02)

19. List the advantages offered by dc chopper drives over line-commutated converter controlled dc drives.(JNTU Nov 07)

20. i. Explain with neat circuit diagram the basic principle of operation of a class A type of chopper. The chopper is connected to R-L-E load. Analyze the same for continuous current mode of operation.

ii. A dc supply of 200v supplied power to separately excited dc motor via a class A thyristors chopper. The motor has an armature circuit resistance of 0.33ohms and inductance of 11mH. The chopper is fully on at the rated motor speed 1200rpm when the armature current is 20A. If the speed is to be reduced to 800rpm with the load torque constant, calculate the necessary duty cycle. If the chopper frequency is 500Hz, is the current continuous? (JNTU Nov 07, 06)

21. i. Distinguish between class A and class B choppers with suitable examples of speed control of motors.ii. A 220v, 190A dc series motor has armature and field resistances of 0.03 and 0.02 respectively.

Running on no load as a generator with field wining connected to a separate source it gave following magnetization characteristic at 500rpm.

22. Motor is controlled by a chopper in dynamic braking with a braking resistance of 2 ohm.a. Calculate motor speed for a duty ratio of 0.6 and motor current of 160A.b. What will be the motor speed for a duty ratio of 0.75 and motor torque equal to half of rated torque?

(JNTU Feb 07, Nov 06)

23. A class-A chopper, operating in time-ratio control, is supplying the armature of the separately excited DC motor. Show that the motor speed-torque relationship is Where V - chopper input voltage, R a - Armature resistance, Ta - motor torque, K- torque constant. (JNTU Nov 05, May 04)

24. A 230v separately excited dc motor takes 50A at a speed of 800rpm. It has armature resistance of 0.4. This motor is controlled by a chopper with an input voltage of 230v and frequency of 500Hz. Assuming continuous condition throughout, calculate and plot speed-torque characteristics for:a. Motoring operation at duty ratios of 0.3 and 0.6.b. Regenerative braking operation at duty ratios of 0.7 and 0.4. (JNTU Nov 05, May 03)

25. i. Explain the principle of speed control of a dc motor and show how it can be achieved by a chopper.ii. A 230v, 1200rpm, 15A separately excited motor has an armature resistance of 1.2. Motor is operated

under dynamic braking with chopper control.Braking resistance has a value of 20.

a. Calculate duty ratio of chopper for motor speed of 1000rpm and braking torque equal to 1.5 times rated motor torque.

b. What will be the motor speed for duty ratio of 0.5 and motor torque equal to its rated torque. (JNTU Nov 05, 03, May 03)

26. Explain with neat circuit diagram the basic principle of operation of a class A type of chopper. The chopper is connected to R-L-E load. Analyze the same for continuous current mode of operation.

(JNTU Nov 05)

27. A dc supply of 200v supplied power to separately excited dc motor via a class A thyristors chopper. The motor has an armature circuit resistance of 0.33 and inductance of 11mH. The chopper is fully on at the rated motor speed 1200rpm when the armature current is 20A. If the speed is to be reduced to 800rpm with the load torque constant, calculate the necessary duty cycle. If the chopper frequency is 500Hz, is the current continuous? (JNTU Nov 05)

28. A dc series motor is powered by a simple (first quadrant) chopper from a 600 V dc source. Armature resistance=0.03Ω, field circuit resistance=0.05 Ω. The back emf constant of the motor Kv=15.27mV/A-rad/s. The average armature current Ia=450 A. The armature current is continuous and has negligible ripple. If the duty cycle of the chopper is 75%, determine

i. the input power from the source, ii. the equivalent input resistance of the chopper drive,iii. speed and developed torque of the motor (JNTU May 04)

29. a. A 230v, 960rpm and 200A separately excited dc motor has an armature resistance of 0.02. The motor is fed from a chopper, which is capable of providing both motoring and braking operations. The source has a voltage of 230V. Assuming continuous conduction:i. Calculate the time ratio of chopper for the motoring action at rated torque and 350 rpm.ii. Determine the maximum possible speed if maximum value of time ratio is 0.95 and maximum

permissible motor current is twice the rated value.b. Draw the necessary waveforms for the above problem. (JNTU Nov 03)

30. a. Discuss with the suitable diagrams I quadrant and II quadrant choppers.b. A constant frequency TRC system is used for the speed control of dc series traction motor from 220v

dc supply. The motor is having armature and series field resistance of 0.025 and 0.015 respectively. The average current in the circuit is 125A and the chopper frequency is 200Hz. Calculate the pulse width if the average value of back emf is 60 volts. (JNTU Nov 03)

31. a. Deduce the mathematical expression for minimum and maximum currents for a class A chopper operated dc motor with back emf.

b. A 220v, 24A, 1000rpm separately excited dc motor having an armature resistance of 2 is controlled by a chopper. The chopping frequency is 500Hz and the input voltage is 230v. Calculate the duty ratio for a motor torque of 1.2 times rated torque at 500rpm. (JNTU Nov 03)

32. a. Explain the principle of speed control of a dc motor and show how it can be achieved by a chopper.b. A 230v, 1200rpm, 15A separately excited motor has an armature resistance of 1.2. Motor is operated

under dynamic braking with chopper control. Braking resistance has a value of 20.i. Calculate duty ratio of chopper for motor speed of 1000rpm and braking torque equal to

1.5times rated motor torque.ii. What will be the motor speed for duty ratio of 0.5 and motor torque equal to its rated torque.

(JNTU Nov 03)

33. i. Explain the operation of two –quadrant chopper .Draw the neat circuit diagram and the relevant wave forms.

ii. A constant frequency TRC system is fed for the control of a dc series motor from 220 volts DC supply. The motor is having armature and field resistances of 0.02 ohms and 0.01 ohms respectively. The average current in the circuit is 100 Amps and the chopper frequency is 200hz.Calculate the pulse width if the average value of the back emf is 50volts.

34. A separately excited DC motor is fed from a chopper operating at 500 Hz with a duty cycle of 50% and is drawing an average current of 10A from a 200 V DC source. A freewheeling diode is connected across it. The motor has negligible armature resistance, a field inductance of 50 mh and a torque

constant of 0.5 N-m/A. Determine the minimum and maximum motor current, motor back e.m.f. and the mechanical torque developed. (GATE 97)

35. A 250 V separately excited DC motor has armature resistance of 2.5 ohms. When driving a load at 600 r.p.m. with constant torque, the armature takes 20 A. The motor is controlled by a DC chopper operating with a frequency of 400 Hz and an input voltage of 250 V DC. What should be the value of duty ratio, if it is desired to reduce the speed from 600 r.p.m. to 400 r.p.m.? Also find the motor speed at rated current and duty ratio of 0.5, if the motor is regenerating. (IES 01)

36. Draw and explain the operation of 4-quadrant chopper.

37. A separately-excited dc motor is supplied from a 60v dc source through a fixed frequency chopper. The rated speed is 900 rpm and the rated current is 30A. Armature circuit resistance is 0.25 ohm. Find the duty cycle ratio of the chopper at rated motor torque for a speed of 300 rpm ignoring current pulsations.

38. What is the duty cycle of a chopper whose input voltage is 240 V dc and the output voltage is 144 V (rms).

39. Draw and explain the speed torque characteristics of a DC motor fed by a DC chopper.

40. Discuss the classification of chopper circuits.

UNIT – V

1. A 3 phase, 4 pole, 50 Hz Induction motor has rotor resistance of 0.2 ohm and stand still reactance of 0.1 ohm. At full load it operates at a slip of 4%. If the voltage is reduced to 50 %, at what speed will the motor operates with full load torque applied. (JNTU May 09)

2. A 3φ, 4 pole, 50Hz SCIM has the following circuit parameters r1=0.05 Ω r2 = 0.09 Ω, x1+x2 = 0.55Ω The motor is star connected and rated voltage is 400v. It drives a load whose troque is proportional to the speed and is given as T1 = 0.05w NW-M. Determine the speed and torque of the motor for a tiring angle of 450 of the AC voltage controller on a 400v, 50Hz supply. (JNTU May 09)

3. Discuss why the rotor of an Induction motor should have very large rotor resistance when it is controlled from a three phase ac voltage controller. (JNTU May 09)

4. An inverter supplies a six pole three-phase cage Induction motor rated at 415V, 50Hz. Determine the 4pproximate voltages required of the inverter for motor speeds 600/800/1500/ 1800 rpm.

(JNTU May 09)

5. A 3 phase, 4 pole, 50 Hz squirrel cage Induction motor has the following circuit parameter. r1 = 0.05ohm, r2 = 0.09ohm,X1 + X2 = 0.55ohm. The motor is star connected and rated voltage is 400V. It drives a load whose torque is proportional to the speed and is given as T1 = 0.05 ω Nw-m. Determine the speed and torque of the motor for a firing angle of 450 of the AC Voltage Controller on a 400V, 50 Hz supply. (JNTU May 09)

6. a. Using 3 phase solid state AC Voltage Controllers explain clearly how it is possible to achieve 4 quadrant operation of 3 phase Induction motors.

b. Draw a closed loop block schematic diagram for the above speed control technique. Mention the merits of the above method of speed control. (JNTU May 09)

7. What is an AC Voltage Controller? Explain with suitable diagrams the various types of solid state 3 phase AC Voltages Controllers which can be used for speed control of 3 phase Induction motors from stator side. Mention the advantages of the AC Voltages Controllers over the other methods of solid-state speed control techniques of 3 phase Induction motor. (JNTU May 09)

8. The equivalent circuit of a three phase Induction motor having a delta connected stator has the following parameters at rated frequency of 50Hz. r1= 0.1Ω, r2= 0.2 Ω,x1= 1.0 Ω, x2= 1.0, xm= 20 ΩThe rated voltage of machine is 250V. Determine the voltage to be applied as a function of stator frequency for rotor frequencies of 0, 2, 3Hz. Consider only the fundamental. (JNTU Nov 08)

9. While explaining the principle of varying the speed of 3 phase Induction motor by v/f method discuss if for the following two different modes.

a. Operation below rated frequencyb. Operation above rated frequency. (JNTU Nov 08)

10. Discuss in detail the role of Cyclo converters for speed control of Induction motor. Draw neat circuit diagram for speed control of 3 phase Induction motor using Cyclo converters. Mention the merits and limitations of the above scheme. (JNTU Nov 08)

11. A three phase, 4 pole, 18 KW, 300V, star connected Induction motor is driven at 50 Hz by a six step voltage source inverter supplied from a DC supply of 200V. The motor equivalent circuit parameters for 50 Hz operation are r1= 0.1Ω, r2= 0.17 Ω,x1= 0.3 Ω, x2= 0.5 Ω, xm= largeCalculate the harmonic torques due to the 5th and 7th harmonic currents. Show that, for operation at 1450 RPM, 50 Hz, the harmonic torques are negligible. (JNTU Nov 08)

12. a. Starting from fundamentals prove that torque developed by the Induction motor is proportional to square of the supply voltage.

b. Draw the speed torque curves for different voltages fed from stator voltage controller.

13. An inverter supplies a six pole three-phase cage Induction motor rated at 415V, 50Hz. Determine the approximate voltages required of the inverter for motor speeds 600/800/1500/ 1800 rpm.

14. a. Explain variable voltage characteristics of Induction motorb. Explain Torque & speed characteristics of Induction motor.

15. Draw the following AC voltage controllers for varying the speed of a 3 phase Induction motora. Star connected controllerb. Delta connected controllerc. Delta connected Stator and controller.

Discuss in detail about the above types of controllers.

16. A pump has a torque-speed curve given by TL = (1.4/10 )N Nm. It is proposed to use a 240V, 50 Hz, 4 pole, star connected Induction motor with the equivalent circuit parameters (referred to stator turns) R1 = 0.25 ohms, R2 = 0.6 ohms, X1 = 0.36 ohms, X2 = 0.36 ohms, Xm = 17.3 ohms. The pump speed N is to vary from full speed 1250 RPM to 750 RPM by voltage control using pairs of inverse-parallel connected thyristors in the lines. Calculate the range of firing angles required. (JNTU Feb 08)

17. What is an AC Voltage Controller?Explain with suitable diagrams the various types of solid state 3 phase AC Voltages Controllers which can be used for speed control of 3 phase Induction motors from stator side. Mention the advantages of the AC Voltages Controllers over the other methods of solid-state speed control techniques of 3 phase Induction motor. (JNTU Feb 08, 07, Nov 05)

18. i. Explain why stator voltage control is suitable for speed control of Induction motors in fan and pump drives. Draw a neat circuit diagram for speed control of scheme of 3 phase Induction motor using AC Voltage Controller.

ii. A 440V, 3 phase, 50 Hz 6 pole 945 RPM delta connected Induction Motor has the following parameters referred to the stator.RS = 2.0, Rr = 2.0, XS = 3, Xr =4.When driving a fan load at rated voltage, it runs at rated speed. The motor speed is controlled by stator voltage control. Determine motor terminal voltage, current and torque at 800 RPM.

(JNTU Nov 07, 06, May 03)

19. A 3-phase, 8 pole, 50Hz Induction motor has the following parameters:r2 = 0.15 ohm, X2 = 0.7 ohmThe motor speed is controlled by varying the applied voltage by an AC Voltage Controller, which operates from a 380V, 50 Hz supply. Determine the applied voltage per phase of the motor to have a slip of 0.15. The motor drives a load with a characteristic of T1 = 0.014ω2 Nw-m. Determine the firing angle of the Converter.. (JNTU Feb 08, 07, Nov 03)

20. i. Why stator voltage control is an inefficient method of Induction motor speed control?ii. A 3 KW, 400V, 50Hz, 4 pole, 1370 RPM, Y-connected Induction motor has the following parameters.

RS = 2ohm, Rr = 5ohm, XS =Xr = 3ohm.Load characteristics are matched with motor such that motor runs at 1370 RPM with full voltage across its terminals. The motor is controlled by terminal voltage control and load torque is proportional to speed. Calculate the motor terminal voltage and current at half the rated speed.

(JNTU Feb 07, May 05, 04, 03)

21. A 3-phase, 4 pole, 50 Hz squirrel cage Induction motor has the following circuit parameter.r1 = 0.05ohm, r2 = 0.09ohm,X1 + X2 = 0.55ohm.The motor is star connected and rated voltage is 400V. It drives a load whose torque is proportional to the speed and is given as T1 = 0.05ωNw-m. Determine the speed and torque of the motor for a firing angle of 450 of the AC Voltage Controller on a 400V, 50 Hz supply. (JNTU Nov 07, 06, 05, 04)

22. i. Using 3 phase solid state AC Voltage Controllers explain clearly how it is possible to achieve 4 quadrant operation of 3 phase Induction motors.

ii. Draw a closed loop block schematic diagram for the above speed control technique. Mention the merits of the above method of speed control. (JNTU Nov 07, 04, May 04)

23. i. Draw the speed torque characteristics which are obtained by stator voltage variation of 3 phase Induction motor.

ii. Draw the circuit diagrams of AC Voltage Controller for delta connected Controller and star connected Controller. How it is possible to change the direction of rotation of 3phase Induction motor using AC Voltage Controllers? (JNTU Nov 06, May 04)

24. i. For stator voltage control scheme of a 3-phase Induction motor discuss about speed range, regeneration, harmonics, torque pulsating, power factor, cost, efficiency and applications.

ii. Draw a block schematic diagram for automatic speed control of 3 phase cage Induction motor using solid state AC Voltage Controller on stator side. (JNTU Nov 05, May 04, 03)

25. A 3-phase 400V, 4 pole, 50Hz, Star connected induction motor has the following parameters referred to the stator: R2’ = 0.2ohms, X2’ = 0.35 ohms. Stator impedance and the magnetizing branch can be ignored. When driving a load with its torque proportional to speed, the motor runs at 1450rpm.

Calculate the magnitude and phase of the voltage (referred to the stator) to be impressed on the slip rings in order that the motor may operate at 1200 rpm and unity power factor. (JNTU Nov 05)

26. A three-phase, 6-pole, star connected squirrel cage Induction motor is to be controlled by terminal voltage variation using pairs of inverse parallel-connected thyristors in each supply line. Sketch a diagram of this arrangement and list the advantages and disadvantages of thyristor control using symmetrical phase-angle triggering, compared with sinusoidal voltage variation. (JNTU Nov 03)

27. a. Explain why stator voltage control is suitable for speed control of Induction motors in fan and pump drives. Draw a neat circuit diagram for speed control of scheme of 3 phase Induction motor using AC Voltage Controller.

b. A 440V, 3 phase, 50 Hz 6 pole 945 RPM delta connected Induction Motor has the following parameters referred to the stator.RS = 2.0, Rr = 2.0, XS = 3, Xr =4.When driving a fan load at rated voltage, it runs at rated speed. The motor speed is controlled by stator voltage control. Determine motor terminal voltage, current and torque at 800 RPM.

(JNTU Nov 03)

28. a. Discuss how the soft start scheme for the 3-phase induction motor drive can be implemented using ac voltage controllers. Mention the restrictions of this scheme.

b. A 440 V, 3-phase, 50 Hz, 6-pole 945 rpm, delta connected induction motor has following parameters referred to stator side: Rs=2.0 , Rr=2.0 , Xs=3.0 , Xr=4.0 . Rated voltage is impressed at the terminals for driving a fan load at rated speed. Stator voltage control employed to get variable speeds. a. If the induction motor is running at 800 rpm, determine the motor terminal voltage, current

flow into the stator and developed torque, (JNTU Nov 03)b. What is the motor speed, current and torque if the terminal voltage is 280 V.

29. Discuss in detail the role of Cyclo converters for speed control of Induction motor. Draw neat circuit diagram for speed control of 3 phase Induction motor using Cyclo converters. Mention the merits and limitations of the above scheme. (JNTU Nov 03)

30. A three phase AC Voltage Controller is used to start and control the speed of a three phase, 100 Hp, 460V, 4 pole Induction motor driving a centrifugal pump. At full load output the power factor of the motor is 0.85 and the efficiency is 80 percent. The motor current is sinusoidal. The controller and motor are connected in delta. Draw relevant circuit diagram.

a. Determine the rms current rating of the thyristors.b. Determine the peak voltage rating of the thyristors.c. Determine the control range of the firing angle . (JNTU Nov 03)

31. A pump has a torque-speed curve given by TL=(1.4/103) N2 Nm. It is proposed to use a 240V, 50 Hz, 4 pole, star connected Induction motor with the equivalent circuit parameters (referred to stator turns) R1 = 0.25 Ω, R2 = 0.6 Ω, X1 = 0.36 Ω, X2 = 0.36 Ω, Xm = 17.3 Ω. The pump speed N is to vary from full speed 1250 rpm to 750 rpm by voltage control using pairs of inverse-parallel connected thyristors in the lines. Calculate the range of firing angles required. (JNTU Nov 03)

32. Draw a closed loop block schematic diagram for the above speed control technique. Mention the merits of the above method of speed control. (JNTU May 04)

33. Draw the speed torque characteristics which are obtained by stator voltage variation of 3 phase Induction motor. (JNTU May 04)

34. Draw the circuit diagrams of AC Voltage Controller for delta connected Controller and star connected Controller. How it is possible to change the direction of rotation of 3phase Induction motor using AC Voltage Controllers ? (JNTU May 04)

35. While explaining the principle of varying the speed of 3 phase Induction motor by v/f method discuss if for the following two different modes.

i. Operation below rated frequency ii. Operation above rated frequency (JNTU May 03)

36. i. Discuss how the soft start scheme for the 3-phase induction motor drive can be implemented using ac voltage controllers. Mention the restrictions of this scheme.

ii. A 440 V, 3-phase, 50 Hz, 6-pole 945 rpm, delta connected induction motor has following parameters referred to stator side: Rs=2.0, Rr=2.0, Xs=3.0, Xr=4.0. Rated voltage is impressed at the terminals for driving a fan load at rated speed. Stator voltage control employed to get variable speeds. i. If the induction motor is running at 800 rpm, determine the motor terminal voltage, current

flow into the stator and developed torque, ii. What is the motor speed, current and torque if the terminal voltage is 280 V. (JNTU May 03)

37. A three phase AC Voltage Controller is used to start and control the speed of a three phase, 100 Hp, 460V, 4 pole Induction motor driving a centrifugal pump. At full load output the power factor of the motor is 0.85 and the efficiency is 80 percent. The motor current is sinusoidal. The controller and motor are connected in delta. Draw relevant circuit diagram.

i. Determine the rms current rating of the thyristors.ii. Determine the peak voltage rating of the thyristors.iii. Determine the control range of the firing angle a. (JNTU May 03)

38. A 440 volts, 3phase 50 Hz, 6pole 945rpm delta connected Induction motor has the following parameters referred to the stator, Rs=2ohms,Rf=2ohms ,Xs=3ohms, Xf=4ohms. When driving a voltage, it runs at rated speed. The motor speed is controlled by stator voltage control. Determine motor terminal voltage, current and torque at 800 rpm. (JNTU May 03)

39. Draw a block schematic diagram for automatic speed control of 3 phase cage Induction motor using solid state AC Voltage Controller on stator side. (JNTU May 03)

40. Explain why stator voltage control is suitable for speed control of induction motor in fan and pump drives. Draw a neat circuit diagram for speed control of scheme of 3 phase induction motor using AC voltage controller. (JNTU May 02)

41. Draw speed torque characteristics of (i) fan load (ii) compressor load.

42. A 5 H.P ,4 pole 50 Hz,3 phase induction motor is fed through a cyclo converter of frequency f/3 calculate speed of the motor at a slip of 5 percent.

43. Explain why stator voltage control is suited for speed control of induction motors in driving fan loads.

44. A 440 V ,3 phase 50 Hz,6-pole 945 rpm, delta connected induction motor has the following parameters referred to the stator Rs=2 ohm, Rr=2 ohm, Xs=3 ohm and Xr=4 ohm. When driving a fan load at rated voltage, it runs at rated speed .The motor speed is controlled by stator voltage control. Determine the motor terminal voltage, current and torque at 800 rpm.

45. A pole changing method of speed control is not popular in case of induction motors why.46. Plot the speed torque characteristics of a centrifugal pump.

47. Give the applications of stator voltage control of induction motor.

48. List the various methods of speed control from stator side of a three phase induction motor and compare their merits and limitations.

49. A 3-phase wound rotor induction motor is controlled by a chopper controlled resistance in it rotor circuit. A resistance of 2 ohm is connected in the rotor circuit and a resistance of 4 ohm is additionally connected during OFF periods of the chopper. The OFF period of the chopper is 4 ms. The average resistance in the rotor circuit for the chopper frequency of 200 Hz isi. 26/5 ohms ii. 24/5 ohms iii. 18/5 ohms iv. 16/5 ohms (IES 01)

UNIT – VI

1. A 3 Phase,1500 rpm Induction motor is developing torque of 3000 Syn. watts at an input frequency of 50Hz. If the motor torque is now reduced to 1500 Syn.watts, determine the new value of stator frequency. The motor is operating in constant HP region. Assume constant rotor frequency and neglect effect of rotor resistance. (JNTU May 09)

2. Mention the reasonsa. Why V/f ratio is maintained constant when the motor is operated below the base speed.b. Why the terminal voltage is maintained constant, when Induction motor is operated above base speed.

Draw relevant speed torque characteristics. (JNTU May 09)

3. Explain the principle of varying the speed of an Induction motor by variable frequency control of stator voltage. Draw the speed torque curves for variable frequency control for motoring and braking modes.

(JNTU May 09)

4. With the help of circuit diagram and waveforms explain the induction motor with current source inverter. Draw the circuit diagram of the Auto-sequentially commutated inverter. (JNTU May 09)

5. a. Compare CSI and VSI drives.b. Show that a variable frequency Induction motor drive develops at all frequencies the same torque for a

given slip-speed when operating at constant flux. (JNTU May 09)

6. An 8 pole, 50Hz, 380V, star connected induction motor has a star connected slip ring rotor. The stator / rotor turns ratio is 1.25. The speed of the motor is controlled by a converter cascade in the rotor circuit. Determine the firing angles of the inverter to get 600rpm and 400rpm at no load. The inverter is connected to a 380V, 3-phase system. Assume no over lap in the rectifier as well as in the inverter . What is the minimum possible speed. (JNTU May 09)

7. a. Draw and explain the speed torque curves with variable frequency control for two different modes.i. Operation at constant flux. ii. Operation at constant (v/f) ratio

b. Explain the advantages of variable frequency drives. (JNTU May 09)

8. A 440V, 50Hz, 50kW, 3-phase induction motor is used as the drive motor in SER system. It is required to deliver constant (rated) motor torque over the full range from 100rpm to the rated speed of 1420rpm. The motor equivalent circuit parameters are: R1 = 0.067Ω, R2’ = 0.04 Ω, R0 = 64.2 Ω, X0 = 19.6 Ω, X1

+ X2’ = 0.177 Ω. Calculate the rotor current, efficiency and power factor at 100rpm.(JNTU May 09)

9. Draw the block diagram of a closed loop synchronous motor drive fed from VSI and explain.

10. A 460V, 100-HP (74.6 KW), 1775 RPM, three-phase, squirrel cage Induction motor has the following equivalent circuit parameters. Rs = 0.060 ohm R’r = 0.0302 ohm L1s = 0.638mH, Lms = 23.3 mH, L1r’ = 0.957 mH The motor is to be driven from a current source inverter with the rotor frequency controlled at the rated value. Maximum output power is to be limited to 80% of the rated value. Motor friction, windage, and core losses may be neglected. The load is to consist of a pump presenting a load

characteristic described by the equation. N.m. Determine the maximum values of motor

speed, inverter frequency, rms motor line current, and fundamental line-to-line motor terminal pd at maximum power output. (JNTU May 09)

11. A 440V, 50Hz, 6 pole star connected, wound rotor induction motor has the following parameters referred to the stator. R1 = 0.08Ω, R2’ = 0.12 Ω, X1 = 0.25 Ω, X2’ = 0.35 Ω, X0 = 10 Ω. An external resistance is inserted into the rotor circuit so that the Tmax is produced at Sm = 2.0. The motor connections are now changed from motoring to single phase AC dynamic braking with three lead connection (one phase in series with other two phases in parallel). Calculate the braking current (line) and torque for a speed of 900rpm. (JNTU May 09)

12. A 6 MW, three phase, 11 kV, 50 Hz, unity power factor, 6-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 9 ohms, rated field current = 60 A. The machine is controlled by variable frequency at constant V/f ratio up to base speed and at constant V above base speed. Calculate the torque and field current for rated armature current, 750 rpm and 0.8 leading power factor. Draw motor characteristics and waveforms under the above method of control. (JNTU May 09)

13. Describe the open-loop and closed loop methods of speed control of a synchronous motor using VSI.(JNTU May 09)

14. a. How do you explain the operation of an induction motor speed control using rotor resistance variation?b. Explain the operation of an induction motor speed control using a chopper control.

(JNTU Nov 08)

15. The speed of a 3-phase slip ring induction motor is controlled by variation of rotor resistance. The full load torque of the motor is 50Nm at a slip of 0.3. The motor drives load having a characteristics T α N2. The motor has 4 poles and operates on 50Hz, 400V supply. Determine the speed of the motor for 0.8 times the rated torque. The operating condition is obtained with additional resistance in the circuit. The resistance is controlled by chopper in the rotor circuit. Determine the average torque developed for a time ratio of 0.4. (JNTU Nov 08)

16. a. Draw and explain a closed loop operation for a static Kramer controlled drive.b. In which way a static Kramer Control is different from static Scherbius drive? (JNTU Nov 08)

17. A 3 Phase, 1500 rpm Induction motor is developing torque of 3000 Syn. watts at an input frequency of

50Hz. If the motor torque is now reduced to 1500 Syn. watts, determine the new value of stator frequency. The motor is operating in constant HP region. Assume constant rotor frequency and neglect effect of rotor resistance. (JNTU Nov 08)

18. A 3 Ph Star connected Induction motor operating at a frequency of 60 Hz consists of 4 poles. The parameters of the stator and rotor referred to stator side are R1 = R2 = 0.024 ohm and X1 = X2 = 0.18 ohm. If the motor is controlled by the variable frequency control with v/f constant ratio determine the following parameters at an operating frequency of 12 Hz. Starting torque and rotor current in terms of their values at rated frequency. (JNTU Nov 08)

19. A 400V, 50HZ Star connected Induction motor is fed from a six step inverter which in turn fed from a six-pulse fully controlled rectifier. The A.C supply mains are rated at 440V, 50HZ. What should be the firing angle of the rectifier to operate the motor at 50 HZ under v/f control? (JNTU Nov 08)

20. With neat block diagrams explain closed loop operation of Induction motor drives. (JNTU Nov 08)

21. Explain the following for variable frequency control of Induction motor.i. The motor has higher efficiency and better low speed performance when feed from a pulse-width

modulated inverter instead of 6-step inverter.ii. The inverter has excellent low speed performance when fed from a Cyclo converter.iii. Cyclo converter is suitable only for low speed drives. (JNTU Feb 08, Nov 03)

22. A 460V, 100-HP (74.6 KW), 1775 RPM, three-phase, squirrel cage Induction motor has the following equivalent circuit parameters. Rs = 0.060 ohm Rr = 0.0302 ohmL1s = 0.638mH, Lms = 23.3 mH, L1r’ = 0.957 mHThe motor is to be driven from a current source inverter with the rotor frequency controlled at the rated value. Maximum output power is to be limited to 80% of the rated value. Motor friction, windage, and core losses may be neglected. The load is to consist of a pump presenting a load characteristic

described by the equation . Determine the maximum values of motor speed, inverter

frequency, rms motor line current, and fundamental line-to-line motor terminal pd at maximum power output. (JNTU Feb 08, Nov 05, 03)

23. With a block schematic diagram explain how the speed of the Induction motor can be controlled automatically (i.e., using closed loop scheme) with voltage source Inverters. Mention the applications of the above scheme. (JNTU Nov 07, 03)

24. Discuss with suitable schematic diagrams the principle of operation of CSI fed Induction motor drives. Mention their merits and limitations. (Nov 07)

25. The equivalent circuit of a three phase Induction motor having a delta connected stator has the following parameters at rated frequency of 50Hz.r1 = 0.1ohm, r2 = 0.2 ohms,x1 = 1.0 ohm, x2 = 1.0 ohm, xm = 20 ohmsThe rated voltage of machine is 250V. Determine the voltage to be applied as a function of stator frequency for rotor frequencies of 0, 2, 3Hz. Consider only the fundamental. (JNTU Nov 07, 06)

26. A three phase, 4-pole, 18 KW, 300V, star connected Induction motor is driven at 50 Hz by a six step voltage source inverter supplied from a DC supply of 200V. The motor equivalent circuit parameters for 50 Hz operation are R1 = 0.1, R2 = 0.17, Xl = 0.3, X2 = 0.5, Xm = large. Calculate the harmonic torques due to the 5th and 7th harmonic currents. Show that, for operation at 1450 RPM, 50 Hz, the harmonic torques are negligible. (JNTU Feb 07, Nov 03)

27. Discuss in detail the role of Cyclo converters for speed control of Induction motor. Draw neat circuit diagram for speed control of 3 phase Induction motor using Cyclo converters. Mention the merits and limitations of the above scheme. (JNTU Feb 07, Nov 06, May 03)

28. i. Draw and explain the speed torque curves with variable frequency control for two different modes. a. Operation at constant flux. b. Operation at constant (V/f) ratio.

ii. Explain the advantages of variable frequency drives. (JNTU Feb 07, May 03)

29. For a 3 phase delta connected, 6 pole, 50 Hz, 400V, 925 RPM, squirrel cage Induction motor the parameters are:Rs = 0.2ohm, Rr = 0.3ohmXs = 0.5ohm, Xr = 1ohmThe motor is fed from a voltage source inverter with a constant v/f ratio from 0 to 50 Hz and constant voltage of 400V above 50Hz frequency. Calculate the

i. Speed for a frequency of 35 Hz and half of full load torque.

ii. Torque for a frequency of 35 Hz and a speed of 650 RPM. (JNTU Nov 06)

30. i. Compare CSI and VSI drives.ii. Show that a variable frequency Induction motor drive develops at all frequencies the same torque for a

given slip-speed when operating at constant flux. (JNTU Nov 06, 04, May 04)

31. The voltages to the terminals of a three phase, 50 KW, 240V induction motor are to be controlled by pairs of inverse-parallel connected thyristors in the supply lines. If the motor full-load efficiency is 0.9 p.u. and the full-load power factor is 0.85, calculate the rms current; mean current and maximum voltage ratings of the thyristors. (JNTU Nov 05)

32. A pump has a torque-speed curve given by TL = (1.4/103) N2 Nm. It is proposed to use a 240V, 50 Hz,

4 pole, star connected Induction motor with the equivalent circuit parameters (referred to stator turns) R1 = 0.25 ohms, R2 = 0.6 ohms, X1 = 0.36 ohms, X2 = 0.36 ohms, Xm = 17.3 ohms. The pump speed N is to vary from full speed 1250 RPM to 750 RPM by voltage control using pairs of inverse-parallel connected thyristors in the lines. Calculate the range of firing angles required. (JNTU Nov 05, 04)

33. With the help of circuit diagram and waveforms explain the induction motor with current source inverter. Draw the circuit diagram of the Auto-sequentially commutated inverter.

(JNTU Nov 05, May 04)

34. Explain the operation of voltage source inverter (180-degree conduction mode), used for induction motor speed control. Draw neat waveforms of line voltages (Vab, Vbc, Vca. and hence show that the phase voltage, Van, is six-step voltage waveform. (JNTU Nov 05, 04)

35. A three phase star connected 50 Hz, 4-pole induction motor has the following approximate per-phase equivalent circuit parameters referred to stator side: Rs=Rr’=0.024 ohm, Xs=Xr’=0.12 ohm. The motor is controlled by the variable frequency control with constant (V/f) ratio. For an operating frequency of 12 Hz, calculate

i. The breakdown torque as a ratio of its value at the rated frequency for the motoring operation, ii. The starting torque and rotor current in terms of their values at the rated frequency.

(JNTU May 04, 03)

36. A three phase, 4 pole, 18 KW, 300V, star connected Induction motor is driven at 50 Hz by a six step voltage source inverter supplied from a DC supply of 200V. The motor equivalent circuit parameters for 50 Hz operation are R1 = 0.1, R2 = 0.17, Xl = 0.3, X2 = 0.5, Xm = large.Calculate the rms current and the harmonic copper losses when this operates at 1450 rpm, 50 Hz.

Estimate the motor efficiency compared with sinusoidal operation. (JNTU May 04, 03)

37. For variable frequency control of Induction motor explain the following points (JNTU May 03)i. For speeds below base speed (V/f) ratio is maintained constant. Why?ii. For speeds above the base speed the terminal voltage is maintained constant. Why?iii. Discuss in detail the merits, demerits of variable frequency control of Induction motor.

38. Describe the converter and control systems used for a. constant air gap flux density and b. constant V/f operation of a synchronous motor. Draw the characteristics of the drive for the two cases.

(JNTU Nov 03)

39. While explaining the principle of varying the speed of 3 phase Induction motor by v/f method discuss if for the following two different modes.i. Operation below rated frequencyii. Operation above rated frequency. (JNTU Nov 03)

40. a. Draw and explain the speed torque curves with variable frequency control for two different modes. i. Operation at constant flux.

ii. Operation at constant (v/f) ratio.Explain the advantages of variable frequency drives. (JNTU Nov 03)

41. Why CSI fed induction motor drive is inherently capable of regenerative mode of operation?42. Discuss the operation of CSI fed 3-phase induction motor. Draw the relevant waveforms.

43. Draw a schematic diagram to show any braking arrangement of 3 phase Induction motor.

44. With neat Waveforms, explain the speed control of 3 phase induction motor fed from a current source inverter. Assume 180 degree conduction mode.

45. Draw speed-torque characteristics of 3 phase induction motor in i. Braking modeii. Motoring modeiii. generating mode

46. For speeds below synchronous speed v/f ratio is kept constant in variable frequency control of inductor motor why.

47. .Explain a speed control scheme for a three phase inductor motor which uses a cyclo converter.

48. Explain the operation of PWM inverter fed three phase induction motor. Bring out its merits.

49. A 3-phase ,delta connected, 6-pole, 50Hz, 400V,925rpm squirrel cage induction motor has the followingparameters:Rs = 0.2ohm, Rr’ = 0.3ohm, Xs = 0.5ohm, Xr’ = 1ohm.

The motor is fed from a voltage source inverter with a constant V/f ratio from 0 to 50Hz and constant voltage of 400V above 50Hz.

i. Obtain the torque at the rated motor current and 75Hz as the ratio of rated full-load torque of the motor.ii. Calculate the motor torque at 30Hz and a slip-speed of 60rpm.

50. The torque produced by a single phase induction rotor fed through an A.C voltage controller for speed control is due to (IES 98)

i. fundamental component of current as well as harmonics, both odd and even. ii. Fundamental component and even harmonic of current iii. Fundamental component and odd harmonic of current. iv. Fundamental component of current alone.

UNIT – VII

1. Draw the circuit diagram and explain the operation of rotor- resistance control using chopper. Mention the advantages and disadvantages of the above method of control. (JNTU Mar 09)

2. A three phase, 460V, 60Hz, 1164 rpm, six pole star connected, wound rotor Induction motor has the following parameters per phase referred to the stator. R1 = 0.4 ohm, R2 = 0.6 ohm, X1 = X2 =1.8 ohm, Xm = 40 Ohm. Stator to rotor turns ratio is 2.5Ω. The motor speed is controlled by static rotor resistance control. The filter resistance is 0.02 Ohm. The value of external resistance is chosen such that α = 0 and the breakdown torque is obtained at stand still. Determine the following:

a. The value of the external resistanceb. α for a speed of 960 rpm at 1.5 times the rated torque. (JNTU Mar 09)

3. A 3-phase, 400V, 50Hz, 6pole, 960 rpm, star connected wound rotor Induction motor has the following constants referred to the stator: Rs = 0.5 ohm, Rr’ =0.7 ohm, Xs = 1.5 ohm, Xr’ = 1.6 ohm. The speed of the motor is reduced to 800 rpm at half full load torque by injecting a voltage in phase with the source voltage into the rotor. Calculate the magnitude and the frequency of the injected voltage. Stator to rotor turns ratio is 2.2. (JNTU Mar 09)

4. a. How do you explain the operation of an induction motor speed control using rotor resistance variation?b. Explain the operation of an induction motor speed control using a chopper control.

(JNTU Mar 09)

5. A 3-phase, 460V, 60Hz, 6 pole, Star connected wound rotor induction motor is controlled by static Kramer drive having the following parameters: R1 = 0.11 Ω, R2’ = 0.09 Ω, X1 = 0.4 Ω, X2’ = 0.6 Ω, X0

= 11.6Ω. The turns ratio of the rotor to stator windings is 0.9. The inductance is very large and its current Id has negligible ripple. The no-load loss is 275W. The turns ratio of the converter AC voltage to supply voltage is 0.5. If the motor is required to operate at a speed of 950 rpm, calculate

a. The inductor currentb. The D.C. voltagec. The delay angle of the converterd. efficiencye. the input power factor of the drive. The load torque which is proportional to speed squared is 455Nm at

1175 rpm. (JNTU Mar 09)

6. A 400 kW, three phase, 3.3 kV, 50 Hz, unity power factor, 4-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 12 ohms, rated field current = 10 A. The machine is controlled by variable frequency at constant V/f ratio. Calculate torque and field current for rated armature current, 900 rpm and 0.8 leading power factor. Draw motor characteristics and waveforms under the above method of control. (JNTU Nov 08)

7. A 6 MW, three phase, 11 kV, 50 Hz, unity power factor, 6-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 9 ohms, rated field current = 60 A. The machine is controlled by variable frequency at constant V/f ratio up to base speed and at constant V above base speed. Calculate the torque and field current for rated armature current, 750 rpmand 0.8 leading power factor. Draw motor characteristics and waveforms under the above method of control. (JNTU Nov 08)

8. Discuss the VSI method of speed control of synchronous motor describe the operation of the converter with waveforms. (JNTU Nov 08)

9. Explain the operation of a synchronous motor fed from an adjustable frequency current source, with circuit diagram and characteristic curves. (JNTU Nov 08)

10. A three phase, 460V, 60Hz, 1164 rpm, six pole star connected, wound rotor Induction motor has the following parameters per phase referred to the stator. R1 = 0.4 ohm, R2 = 0.6 ohm, X1 = X2 =1.8 ohm, Xm = 40 Ohm. Stator to rotor turns ratio is 2.5. The motor speed is controlled by static rotor resistance control. The filter resistance is 0.02 Ohm. The value of external resistance is chosen such that α = 0 and the breakdown torque is obtained at stand still. Determine the following:

a. The value of the external resistanceb. α for a speed of 960 rpm at 1.5 times the rated torque. (JNTU Nov 08)

11. Draw the circuit diagram and explain the operation of rotor- resistance control using chopper. Mention the advantages and disadvantages of the above method of control. (JNTU Nov 08)

12. Explain static motor resistance control for speed control of I.M. Draw speed & torque characteristics.

13. a. Why rotor resistance control is preferred in low power crane drives? (JNTU Nov 08)b. What are the advantages of static rotor resistance control over conventional method of rotor resistance

control? Explain its principle of operation with suitable circuit diagrams and characteristics.

14. An 8 pole, 50Hz, 380V, star connected induction motor has a star connected slip ring rotor. The stator / rotor turns ratio is 1.25. The speed of the motor is controlled by a converter cascade in the rotor circuit. Determine the firing angles of the inverter to get 600rpm and 400rpm at no load. The inverter is connected to a 380V, 3-phase system. Assume no over lap in the rectifier as well as in the inverter . What is the minimum possible speed. (JNTU Feb 08, 07)

15. A 440V, 50Hz, 50kW, 3-phase induction motor is used as the drive motor in SER system. It is required to deliver constant (rated) motor torque over the full range from 100rpm to the rated speed of 1420rpm. The motor equivalent circuit parameters are:R1 = 0.067ohms, R2’ = 0.04ohms, R0 = 64.2ohms, X0 = 19.6ohms, X1 + X2’ = 0.177ohms. Calculate the rotor current, efficiency and power factor at 100rpm. (JNTU Feb 08)

16. A 3-phase slip ring induction motor has a chopper controlled resistance in the rotor circuit for speed control. With the chopper completely ON always, the maximum torque occurs at a slip of 0.2. With the chopper completely OFF the maximum torque occurs at a slip of 1. Determine the value of the resistance in the chopper. (JNTU Feb 08)

17. A SER controlled slip ring motor drives a fan load having a characteristic TL = kN2.The motor is rated at 440V, 50Hz, 100kW. The speed is to be controlled from a rated value of 1420 to 750rpm. The equivalent circuit has the following parameters: R1 = 0.052 ohms, R2’ = 0.06 ohms, X1 + X2’ = 0.29ohms, X0 = 10ohms. Stator / rotor turns ratio = 1.2. Determine the firing angle and draw the speed-torque characteristic. (JNTU Nov 07, 06)

18. A 3-phase, 460V, 60Hz, 1164rpm, 6 pole, star connected, wound rotor induction motor has the following parameters referred to the stator: R1 = 0.4ohms, R2’ = 0.6ohms, X1 = X2’ = 1.8ohms, X0 = 40ohms, Stator to rotor turns ratio = 2.5. The motor speed is controlled by static rotor resistance control. The filter resistance is 0.02ohms. The value of the external resistance is chosen such that á = 0 and the breakdown torque is obtained at Standstill: Determine the following:The value of the external resistance a for a speed of 60rpm at 1.5 times the rated torque. The speed for a = 0.6 and 1.5 times the rated torque neglect the friction and windage loss. (JNTU Nov 07)

19. A 600V, 50Hz, 30kW, 3-phase induction motor is used as the drive motor in an SER system. It is required to deliver constant (rated) motor torque over the full range from 100rpm to the rated speed of 1000rpm. The motor equivalent circuit parameters are:R1 = 0.05 ohms, R’ = 0.07ohms, R0 = 53 ohms, X0 = 23 ohms, X1+ X2’ = 0.153 ohms.Stator to rotor turns ratio is 1.3. Calculate the motor currents, efficiency and power factor at 300 rpm.

(JNTU Nov 07, 06)

20. A fan with a load characteristic TL = kN2 is to be driven by an SER drive incorporating a 440V, 50Hz, 100kW induction motor. It is required to deliver rated speed of 1440 rpm and to provide smooth speed control down to 750 rpm. The motor equivalent circuit parameters referred to primary turns are R1 = 0.052ohm, R2’ = 0.06ohm, Xm = 10ohm, X1 + X2’ = 0.29ohm, R0 = 100ohm. Stator

to rotor turns ratio: 1.2. Calculate the motor efficiency and power factor at 750rpm. Friction and windage effects may be neglected. It is assumed that the motor is started from rest and run upto 750 rpm by the secondary resistance method. (JNTU Nov 07, May 04)

21. A 400V, 50Hz, 40kW, 3-phase induction motor is used as the drive motor having the following parameters R1 = 0.067, R2’ = 0.04, R0 = 50, X0 = 20. X1 + X2’ = 0.2. The SER drive is to be used for the speed control of a constant torque load over the speed range 1000-1420rpm. Conventional starting equipment is used to drive the motor to 1000rpm when it is switched to SER control. Determine the necessary range of SCR firing angles, efficiency and power factor at 1420rpm. (JNTU Feb 07)

22. A 440V, 50Hz, 50kW, 3-phase slip ring induction motor has the following equivalent circuit parameters R1 = 0.07, R2’ = 0.05, X1 + X2’ = 0.2, X0 = 20. The speed of the motor at rated load is 1420rpm. Determine the resistance in the chopper circuit so that the speed can be controlled in the range 1420 - 1000rpm at constant torque. Determine the time ratio fori. 1100rpm ii. 750rpm and iii. 500rpm. (JNTU Feb 07)

23. A 3-phase, 420V, 50Hz, star connected induction motor has the following parameters: R 1 = 2.95 ohms, R2= 2.08, X1 = 6.82 ohms, X2’ = 4.11 ohms per phase. Neglect core loss. The motor draws a current 6.7A at no load and controlled by rotor resistance controller. A resistance Re ohm has been controlled by chopper. Determine the value of Re to get a speed range of 1500 to 500 rpm, assuming a turns ratio of two between stator and rotor. The torque and speed of the load are related by T α N. Determine the characteristics giving the speed Vs time ratio of the chopper. (JNTU Feb 07, Nov 05, 04)

24. i. What are the assumptions made in the static resistance control of wound rotor induction motors?ii. Draw the speed-torque characteristics of a rotor resistance controlled induction motor and explain the

effect of rotor resistance variation. iii. Why rotor resistance control is preferred in low power crane drives? (JNTU May, Nov 06, 04)

25. A 440V, 50Hz, 6 pole star connected, wound rotor induction motor has the following parameters referred to the stator. R1 = 0.08 ohms, R2’ = 0.12 ohms, X1 = 0.25 ohms, X2’ = 0.35 ohms, X0 = 10 ohms.An external resistance is inserted into the rotor circuit so that the T max is produced at Sm = 2.0. The motor connections are now changed from motoring to single phase AC dynamic braking with three lead connection (one phase in series with other two phases in parallel). Calculate the braking current (line) and torque for a speed of 900rpm. (JNTU Nov 05)

26. A 3-phase, 400V, 50Hz, 4 pole, 1400rpm, star connected wound rotor induction motor has the following parameters referred to the stator R1 = 2 Ohms, R2’ = 3 Ohms, X1 = X2’ = 3.5 Ohms. The stator to rotor turns ratio is 2. The motor speed is controlled by static Scherbius drive. The inverter is directly connected to the source. Determine.

i. The speed range of the drive when max = 1650ii. The firing angle for 0.4 times the rated motor torque and speed of 1200 rpm.iii. Torque for a speed of 1050rpm and firing angle of 950 (JNTU Nov 05, May 04)

27. The speed of a 3-phase slip ring induction motor is controlled by variation of rotor resistance. The full load torque of the motor is 50Nm at a slip of 0.3. The motor drives load having characteristics T N2. The motor has 4 poles and operates on 50Hz, 400V supply. Determine the speed of the motor for 0.8

times the rated torque. The operating condition is obtained with additional resistance in the circuit. The resistance is controlled by chopper in the rotor circuit. Determine the average torque developed for a time ratio of 0.4. (JNTU Nov 05)

28. A 3-phase, 50Hz Star connected, 970rpm, 6-pole induction motor has the following parameters referred to the stator. R1 = 0.2ohm, R2’ = 0.15ohm, X1 = X2’ = 0.4ohm. Stator to rotor turns ratio = 3.5. The motor is controlled by the static kramar drive. The drive is designed for a speed range of 30% below the synchronous speed. The maximum value of firing angle is 170°. Calculate:

i. Turns ratio of the transformerii. Torque for a speed of 750 rpm and a = 140°.iii. Firing angle for half the rated motor torque and a speed of 850 rpm. (JNTU Nov 04)

29. The speed of a 3-phase slip ring induction motor is controlled by variation of rotor resistance. The full load torque of the motor is 50Nm at a slip of 0.3. The motor drives load having a characteristics T a N2. The motor has 4 poles and operates on 50Hz, 400V supply. Determine the speed of the motor for 0.8 times the rated torque. The operating condition is obtained with additional resistance in the circuit. The resistance is controlled by chopper in the rotor circuit. Determine the average torque developed for a time ratio of 0.4. (JNTU Nov 04)

30. A 3-phase 400V, 4 pole, 50Hz, Star connected induction motor has the following parameters referred to the stator: R2’ = 0.2ohm, X2’ = 0.35ohm. Stator impedance and the magnetizing branch can be ignored. When driving a load with its torque proportional to speed, the motor runs at 1450rpm. Calculate the magnitude and phase of the voltage (referred to the stator) to be impressed on the slip rings in order that the motor may operate at 1200 rpm and unity power factor. (JNTU Nov 04)

31. i. What are the effects of line side inductance in a slip energy recovery scheme? ii. Derive the relation of de-rating of an induction motor when it is having different harmonics under slip

energy recovery scheme. iii. Why the rotor resistance of an induction motor operating under slip energy recovery scheme should

have less rotor resistance. (JNTU May 04, 03)

32. i. Compare the power flow diagram of a normal speed control method with that of slip energy recovery scheme (SER) for an induction motor.

ii. In which way the (SER) can be made operable for both super synchronous and sub-synchronous speed control. (JNTU May 04, 03)

33. A 440V, 50Hz, 50kW, 3-phase induction motor is used as the drive motor in SER system. It is required to deliver constant (rate iv. motor torque over the full range from 100rpm to the rated speed of 1420rpm. The motor equivalent circuit parameters are: R1 = 0.067ohm, R2’ = 0.04ohm, R0 = 64.2ohm, X0 = 19.6ohm, X1 + X2’ = 0.177W. Calculate the rotor current, efficiency and power factor at 100rpm.

(JNTU May 04)

34. i. How do you explain the operation of an induction motor speed control using rotor resistance variation?ii. Explain the operation of an induction motor speed control using a chopper control.

(JNTU May 04)

35. i. Why the static Kramer drive has a low range of speed control?

ii. A 3-phase 400V, 50Hz, 6 pole 960 rpm delta connected wound rotor induction motor has the following constants referred to the stator: R1 = 0.3ohm, = 0.5ohm and Xr’ = 1.8ohm. The speed of the motor is reduced to 750rpm at half full load torque by injecting a voltage in phase with the source voltage into the rotor. Calculate the magnitude and the frequency of the injected voltage. Stator to rotor turns ratio is 2.2. (JNTU May 04)

36. Why rotor resistance control is preferred in low power crane drives (JNTU May 04)

37. What are the assumptions made in the static resistance control of wound rotor induction motors?(JNTU May 03)

38. a. How do you explain the operation of an induction motor speed control using rotor resistance variation?b) Explain the operation of an induction motor speed control using a chopper control. (JNTU Nov 03)

39. a. Why the static Kramer drive has a low range of speed control?b. A 3-phase 400V, 50Hz, 6 pole 960 rpm delta connected wound rotor induction motor has the following

constants referred to the stator:a. R1 = 0.3, R2’= 0.5 and Xr

’ = 1.8. The speed of the motor is reduced to 750rpm at half full load torque by injecting a voltage in phase with the source voltage into the rotor. Calculate the magnitude and the frequency of the injected voltage. Stator to rotor turns ratio is 2.2.

(JNTU Nov 03)

40. A fan with a load characteristic TL = kN2 is to be driven by an SER drive incorporating a 440V, 50Hz, 100kW induction motor. It is required to deliver rated speed of 1440 rpm and to provide smooth speed control down to 750 rpm. The motor equivalent circuit parameters referred to primary turns are

R1 = 0.052, R2’ = 0.06, Xm = 10, X1 + X2

’ = 0.29, R0 = 100.Stator to rotor turns ratio: 1.2 Calculate the motor efficiency and power factor at 750rpm. Friction and windage

effects may be neglected. It is assumed that the motor is started from rest and run upto 750 rpm by the secondary resistance method (JNTU Nov 03)

41. A 3-phase, 400V, 50Hz, 4 pole, 1400rpm, star connected wound rotor induction motor has the following parameters referred to the stator R1 = 2, R2

’ = 3, X1 = X2’ = 3.5. The stator to rotor

turns ratio is 2. The motor speed is controlled by static Scherbius drive. The inverter is directly connected to the source. Determine.

a. The speed range of the drive when max = 165 b. The firing angle for 0.4 times the rated motor torque and speed of 1200 rpm.c. Torque for a speed of 1050rpm and firing angle of 95. (JNTU Nov 03)

42. Draw the speed-torque characteristics of a rotor resistance controlled induction motor and explain the effect of rotor resistance variation. (JNTU May 02)

43. A 2.2 KV, 50 Hz, 3 phase, 6 polestar connected squirrel cage induction motor has the following parameters.Rs=0.075,Rr=0.12,Xs=Xr=5.The combined inertia of the motor and local is100Kg-m2

i. calculate the time taken and energy dissipated in the motor when it is stopped by pluggingii. What resistance should be inserted in the rotor to stop motor by plugging in the minimum timeiii. Also calculate the energy dissipated in the external resistance during braking

44. What is the effect of rotor resistance on starting torque of a slip ring induction motor.

45. What are the advantages of static Scheribus drive system

46. .Discuss a slip power recovery scheme for a three phase slip ring induction motor what are its merits and demerits.

47. Why is the slip-power recovery scheme suitable for drives with low speed range why? 48. A 3phase, 440 volts ,6pole ,970rpm,50hz star connected induction motor has the following parameters:

Rs=0.2ohms:R1f=0.15 ohm Xs=:X1f The stator to rotor turns ratio is 3.5. The motor speed is controlled by the static scherbius Drive. The drive is designated for a speed range of 30% below the synchronous speed. The maximum value of firing angle is 170

0. Calculate

(i) Turns ratio of the transformer and (ii) Torque for a speed of 750rpm

49. A 440V, 50Hz, 35kW, 3-phase induction motor is used as the drive motor in SER system. It is required to deliver constant (rated) motor torque over the full range from 100rpm to the rated speed of 1440rpm. The motor equivalent circuit parameters are:R1 = 0.037W, R2’ = 0.04W, R0 = 44.2W, X0 = 19.6W, X1 + X2’ = 0.25W. Calculate the rotor current, efficiency and power factor at 100rpm

50. In the rotor resistance control, what type of motor speed-torque characteristic will be obtained if one phase has a loose contact?

51. What are the advantages of static rotor resistance control (using diode bridge and switch controlled resistor) over conventional methods of rotor resistance control?

52. Why is the power factor of the slip power recovery scheme of speed control of induction motor low?

53. Why a resistance starter is generally required for the induction motor drive employing slip-power recovery? Can you use a semiconductor switch controlled resistance connected after the diode bridge to avoid resistance starter?

54. Why has the static kramer Drive a low range of speed control?

55. A three phase, 400V, 6 pole, 970 rpm, 50 Hz, Y connected induction motor has the following parameters referred t the statorRs=0.2W, R’r =0.15W, Xs=X’r=0.4WThe stator to rotor turns ratio is 3.5The motor speed is controlled by the static scherbius drive. The drive is designed for a speed range of 30% below the synchronous speed. The maximum value of firing angle is 170 degree. Calculate

i. Turns ratio of the transformerii. Torque for a speed of 750- rpm and 140 degreesiii. firing angle for half the rated motor torque and a speed of 850 rmp.

56. Explain the principle of and an application of variable speed and constant frequency generation schemes

57. Compare the various types of single phase induction motors in terms of performance and explain where they are employed.

UNIT – VIII

1. In variable frequency control of asynchronous motor why (V/f) ratio is maintained constant up to base speed and V constant above base speed. Draw the relevant characteristics. (JNTU Mar 09)

2. What are the various possible combinations of voltage source DC link converters to obtain a variable voltage variable frequency supply to feed a Synchronous motor? Draw the circuit diagrams and discuss in detail. (JNTU Mar 09)

3. Explain the principle of operation of separately controlled synchronous motor fed from VSI source.(JNTU Mar 09)

4. Explain the operation of a synchronous motor fed from an adjustable frequency current source, with circuit diagram and characteristic curves. (JNTU Mar 09)

5. Describe the open-loop and closed loop methods of speed control of a synchronous motor using VSI.(JNTU Mar 09)

6. A 6 MW, three phase, 11 kV, 50 Hz, unity power factor, 6-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 9 ohms, rated field current = 50 A. The machine is controlled by variable frequency at constant V/f ratio up to base speed and at constant V above base speed. Calculate the armature current and power factor for regenerative braking power output of 4.2 MVA at 800 rpm and rated field current. Draw motor characteristics and waveforms under the above method of control. (JNTU Mar 09)

7. An 8 MW, 3-phase, 6.6 kV, 50 Hz, 6-pole, Y-connected wound-field synchronous motor has the following parameters: Xm = 8 ohm, Xsf = 0.5 ohm, rated pf = 1, Rs = 0.01 ohm, rated field current = 180 A. Field winding resistance = 1.2 ohm. Calculate the pf, armature current, efficiency at half the rated torque and at rated field current. Core, friction and windage loss assumed constant at 9 KW. Draw motor characteristics and waveforms under the above method of control. (JNTU Mar 09)

8. Describe separate controlled mode and self-controlled mode of operation of a synchronous motor drive in detail and compare them. (JNTU Mar 09)

9. Draw the block diagram of a closed loop synchronous motor drive fed from VSI and explain.(JNTU Mar 09)

10. Describe the open-loop and closed loop methods of speed control of a synchronous motor using VSI.(JNTU Nov 08)

11. Describe self-controlled and load-commutated inverter controlled synchronous motor drives in detail and compare them (JNTU Nov 08)

12. Draw the block diagram of a closed loop synchronous motor drive fed from VSI and explain.(JNTU Nov 08)

13. Explain separate control & self control of synchronous motor. (JNTU Nov 08)

14. With suitable circuit diagrams discuss in detail the principle of operation of Self controlled Synchronous motor drive employing a Cyclo converter. (JNTU Nov 08)

15. A 20 kW, 3-phase, 440V, 4 pole, delta connected permanent magnet synchronous motor has following parameters. Xs = 5 ohm, Rs = 0, rated power factor =1.0. Machine is controlled by variable frequency control at a constant (V/f) ratio. Calculate armature current, torque angle and power factor at half full load torque and 750 rpm. (JNTU Nov 08)

16. a. What is a self control mode of Synchronous motor?b. Draw and explain the block diagram of a self controlled synchronous motor fed from a three phase

inverter. (JNTU Nov 08)

17. A 10 MW, 3-phase, 6.6 kV, 50 Hz, 4-pole, Y-connected wound-field synchronous motor has the following parameters: Xm = 8 ohm, Xsf = 0.5 ohm, rated pf = 1, Rs = 0.01 ohm, rated field current = 210 A. Field winding resistance = 1.2 ohm. Calculate the field current to get unity pf at 60% of rated torque. Draw motor characteristics and waveforms under the above method of control.

(JNTU Feb 08)

18. Describe the open-loop and closed loop methods of speed control of a synchronous motor using VSI. (JNTU Feb 08, 07, Nov 07, 05, 04, 03)

19. Describe cyclo converter drive versus VSI drive for synchronous motor in detail and state their advantages and disadvantages. (JNTU Feb 08, Nov 05, 04)

20. Draw the block diagram of a closed loop synchronous motor drive fed from VSI and explain. (JNTU Feb 08, 07, Nov 06, Nov, May 04, 03)

21. For variable frequency control of synchronous motor describe the power circuit and control logic used for

i. Below base speed and ii. Above base speed. Draw the characteristics of the drive for the two cases.(JNTU Feb 08, Nov 06, 03)

22. Describe separate controlled mode and self-controlled mode of operation of a synchronous motor drive in detail and compare them. (JNTU Feb 08, Nov 05, 04)

23. Describe self-controlled and load-commutated inverter controlled synchronous motor drives in detail and compare them (JNTU Nov 07, 05, 04)

24. Discuss the CSI method of speed control of synchronous motor and describe the operation of the converter with waveforms. (JNTU Nov, Feb 07, May 04, 03)

25. How is the output voltage of a VSI improved by PWM techniques? Explain how you will use this converter for speed control of a synchronous motor. (JNTU Feb 07, Nov 07, 06, May 04)

26. A 500 kW, 3-phase, 6.6 kV, 60 Hz, 6-pole, Y-connected wound-field synchronous motor has the following parameters: Xm = 78, Xsf = 3, rated pf = 1, n = 5, Rs = negligible. The motor speed is controlled by variable frequency control with a constant V/f ratio up to base speed and rated terminal voltage above base speed.Calculate and plot T, Pm, V, Im, and IF versus speed for the motor operation at rated armature current and unity pf. What is the range of constant power operation? Neglect friction, windage and core loss. Draw motor characteristics and waveforms under the above method of control.


27. Describe CSI fed and VSI fed synchronous motor drives in detail with block diagrams and compare them. (JNTU Feb 07, Nov 04)

28. Describe self controlled and load commuted inverter controlled synchronous motor drives in detail and compare them? (JNTU Feb 07, Nov 06, May 03)

29. A 400 kW, three phase, 3.3 kV, 50 Hz, unity power factor, 4-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 12 ohms, rated field current = 10 A. The machine is controlled by variable frequency at constant V/f ratio. Calculate the armature current and power factor for regenerative braking torque equal to rated motor torque, 900 rpm and rated field current. Draw motor characteristics and waveforms under the above method of control.

(JNTU Nov 06, 03)

30. An 8 MW, 3-phase, 6.6 kV, 50 Hz, 6-pole, Y-connected wound-field synchronous motor has the following parameters: Xm = 8 ohm, Xsf = 0.5 ohm, rated pf = 1, Rs = 0.01 ohm, rated field current = 180 A. Field winding resistance = 1.2 ohm. Calculate the pf, armature current, efficiency at half the rated torque and at rated field current. Core, friction and windage loss assumed constant at 9 KW. Draw motor characteristics and waveforms under the above method of control. (JNTU Nov 06)

31. A 6 MW, three phase, 11 kV, 50 Hz, unity power factor, 6-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 9 ohms, rated field current = 60 A. The machine is controlled by variable frequency at constant V/f ratio up to base speed and at constant V above base speed. Calculate the torque and field current for rated armature current, 750 rpm and 0.8 leading power factor. Draw motor characteristics and waveforms under the above method of control. (JNTU Nov 05)

32. Discuss the VSI method of speed control of synchronous motor describe the operation of the converter with waveforms. (JNTU Nov 05, 04)

33. Discuss in detail the role of Cyclo converters for speed control of Induction motor.Draw neat circuit diagram for speed control of 3 phase Induction motor using Cyclo converters. Mention the merits and limitations of the above scheme. (JNTU Nov 05)

34. Explain, under what conditions the load commutation for CSI can be applied and discuss the operation with modified CSI. Give few advantages. (JNTU May, Nov 04, 03)

35. Describe the cycloconverter method of controlling the speed of a synchronous motor. When is it used? A cycloconverter operating at 400 V, 50 Hz supply draws a power of 10 kVA and is driving a synchronous motor at 200 A, 200 V. Calculate firing angle and input pf, assuming efficiency of the cycloconverter = 96 % and motor pf = 0.8 lag. (JNTU Nov 04)

36. Explain the operation of a synchronous motor fed from an adjustable frequency current source, with circuit diagram and characteristic curves. (JNTU Nov, May 04, 03)

37. Describe the converter and control systems used for (a). constant air gap flux density and (b). constant V/f operation of a synchronous motor. Draw the characteristics of the drive for the two cases.

(JNTU Nov 06, 03)38. Explain the power and control circuits for a three phase synchronous motor under i. constant terminal

voltage and frequency ii. constant line current and frequency. Draw the characteristics of the drive for the two cases and compare. (JNTU Nov 03)

39. Describe the converter used for high power low frequency synchronous motor drives with relevant waveforms? (JNTU May 03)

40. Discuss the closed loop operation of synchronous motor drives with neat block diagram.(JNTU May 03)

41. Explain the method of separate control of synchronous motor with a case study (JNTU May 02)

42. Discuss the speed torque characteristics of CSI fed synchronous motor with necessary waveforms. (JNTU May 03)

43. Describe self-controlled and load-commutated inverter controlled synchronous motor drives in detail and compare them (JNTU Nov 03)

44. For variable frequency control of synchronous motor describe the power circuit and control logic used for (a) below base speed and (b) above base speed. Draw the characteristics of the drive for the two cases. (JNTU Nov 03)

45. Draw the block diagram of a closed loop synchronous motor drive fed from VSI and explain.(JNTU Nov 03)

46. A 400 kW, three phase, 3.3 kV, 50 Hz, unity power factor, 4-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 12 ohms, rated field current = 10 A. The machine is controlled by variable frequency at constant V/f ratio. Calculate torque and field current for rated armature current, 900 rpm and 0.8 leading power factor. Draw motor characteristics and waveforms under the above method of control. (JNTU Nov 03)

47. Describe the open-loop and closed loop methods of speed control of a synchronous motor using VSI.(JNTU Nov 03)

48. A 400 kW, three phase, 3.3 kV, 50 Hz, unity power factor, 4-pole, star-connected synchronous motor has the following parameters: armature resistance = 0, synchronous reactance = 12 ohms, rated field current = 10 A. The machine is controlled by variable frequency at constant V/f ratio. Calculate the armature current and power factor for regenerative braking torque equal to rated motor torque, 900 rpm and rated field current. Draw motor characteristics and waveforms under the above method of control.

(JNTU Nov 03)

49. Explain, under what conditions the load commutation for CSI can be applied and discuss the operation with modified CSI . Give few advantages. (JNTU Nov 03)

50. How is the output voltage of a VSI improved by PWM techniques? Explain how you will use this converter for speed control of a synchronous motor. (JNTU May 02)

51. Write short notes on the following (JNTU May 02)i. 3-phas semi controlled converters ii. Cyclo converters iii. Static Kramer drives

52. i. What is the basic difference between true synchronous mode and self controlled mode for variable frequency control of synchronous motor?

ii. Why is cyclo converter controlled synchronous motor preferred for inverter controlled synchronous motor drive for low speed applications (JNTU May 02)

53. In a self-controlled synchronous motor fed from a variable frequency inverter i. The rotor poles invariably have damper windings ii. There are stability problemsiii. The speed of the rotor decides stator frequency iv. The frequency of the stator decides the rotor speed. (IES 02)

54. In self control mode drive of syn. Motors, damper windings are not needed. Why ?

55. What are different types of roter position sensors used in self-controlled synchronous motor drive.

56. Explain steady state and torque angle characteristics of synchronous motion.

57. Derive expressions for no of revolutions made by the motor from rated speed to rest

58. A 400V 8 pole 3 phase synchronous motor and its load have a total moment of inertia of 630Kg-m2.Determine the time and the number of revolutions made by it to come to stand still if rheostatic

braking is employed which gives an initial electric braking torque of 690Kg-m2.Assume a frictional torque of 1.4 Kg-m.

59. Explain what is load equalization. How do you determine the moment of inertia of a flywheel.

60. Explain the Rheostatic braking adopted in three phase synchronous machine drives

7. SUBJECT DETAILS

7.2 POWER SYSTEM ANALYSIS


7.2.2 Scope

7.2.3 Prerequisites

7.2.4 Syllabus

i. JNTU

ii. GATE

iii. IES


7.2.6 Websites


7.2.8 Journals

7.2.9 Findings and Developments

7.2.10 Session Plan




i. JNTU

ii. GATE

iii. IES


The increasing demand for electric power coupled with resource and environmental constraints creates several challenges to system planners. The need for computational aids in power system engineering led to the design of special purpose analog computers. The process of applying a computer to the solution of engineering problems involves a number of distinct steps such as problem definition, mathematical formulation, selection of a solution technique, programme design, programming etc. The relative importance of each of these steps varies from problem to problem. Moreover, all steps are closely related and play an important role in the decisions that must be made.

The objective of power system analysis and study is to plan, design and implement a power system which provides a reliable power of rated voltage and frequency at affordable cost to the customers. The power system problems are modeled as mathematical problems and solved by analytical / conventional and numerical methods. The invention of fast processing computer with the ability to deal with large databases made a revolution in this field.

The course is designed in such a way to understand and simulate the power system problems like load flow, fault analysis and stability study.

7.3.2 SCOPE

This subject enables students to find alternative solution techniques for load flow problem. This also helps in designing a power system, its operation and expansion. Enables in setting up energy control centers with on-line computers performing all signal processing through remote acquisition system.

7.3.3 PREREQUISITES

It needs complete understanding of power system modeling, analysis and various calculations and also broader understanding of optimization method and solving differential equations are necessary.

Modeling course in power system, Complex algebra, fundamental course in numerical methods and differential equations, Programming methodology using C or MATLAB

7.3.4.i SYLLABUS - JNTU

UNIT-IOBJECTIVE

This unit presents a comprehensive coverage of graph theory and formation of Y-bus.

SYLLABUS

Graph Theory: Definitions, Bus Incidence Matrix, Ybus formation by Direct and Singular Transformation Methods, Numerical Problems.

UNIT-IIOBJECTIVE

The unit gives idea for the formation of Z-bus by different methods.

SYLLABUS

Formation of ZBus: Partial network, Algorithm for the Modification of Z-Bus Matrix for addition element for the following cases: Addition of element from a new bus to reference, Addition of element from a new bus to an old bus, Addition of element between an old bus to reference and Addition of element between two old busses (Derivations and Numerical Problems).- Modification of Z-Bus for the changes in network (Problems ).

UNIT-IIIOBJECTIVE

This unit presents a comprehensive coverage of the power flow solution of an interconnected system using Gauss-Seidal method during normal operation

SYLLABUS

Power flow Studies -1 : Necessity of Power Flow Studies – Data for Power Flow Studies – Derivation of Static load flow equations – Load flow solutions using Gauss Seidel Method: Acceleration Factor, Load flow solution with and without P-V buses, Algorithm and Flowchart. Numerical Load flow Solution for Simple Power Systems (Max. 3-Buses): Determination of Bus Voltages, Injected Active and Reactive Powers (Sample One Iteration only) and finding Line Flows/Losses for the given Bus Voltages.

UNIT-IVOBJECTIVE

This unit presents a iterative techniques like NR and Fast Decoupled method for solving Non linear power flow equations

OBJECTIVE

Newton Raphson Method in Rectangular and Polar Co-Ordinates Form: Load Flow Solution with or without PV Busses- Derivation of Jacobian Elements, Algorithm and Flowchart. Decoupled and Fast Decoupled Methods.- Comparison of Different Methods.

UNIT-VOBJECTIVE

This unit covers three-phase symmetrical and unsymmetrical fault analysis.

SYLLABUS

Short Circuit Analysis-1 : Per-Unit System of Representation. Per-Unit equivalent reactance network of a three phase Power System, Numerical Problems. Symmetrical fault Analysis : Short Circuit Current and MVA Calculations, Fault levels, Application of Series Reactors, Numerical Problems.

UNIT-VIOBJECTIVE

This unit provides idea about symmetrical components and representation of power system networks, power system components. In symmetrical components for fault analysis.

SYLLABUS

Short Circuit Analysis-2 : Symmetrical Component Theory: Symmetrical Component Transformation, Positive, Negative and Zero sequence components: Voltages, Currents and Impedances. Sequence Networks : Positive,

Negative and Zero sequence Networks, Numerical Problems. Unsymmetrical Fault Analysis : LG, LL, LLG faults with and without fault impedance, Numerical Problems.

UNIT-VIIOBJECTIVEThis unit provides idea about 3 types of stabilities and methods to improve study state stability.

SYLLABUS

Power System Steady State Stability Analysis : Elementary concepts of Steady State, Dynamic and Transient Stabilities. Description of : Steady State Stability Power Limit, Transfer Reactance, Synchronizing Power Coefficient, Power Angle Curve and Determination of Steady State Stability and Methods to improve steady state stability.

UNIT-VIIIOBJECTIVE

This unit presents power system stability problems. The dynamic and transient stability using equal area criterion is discussed, and the result is represented graphically, providing physical insight into the dynamic behaviour of the machine. This unit presents a numerical solution to the non-linear differential equations

SYLLABUS

Power System Transient State Stability Analysis : Derivation of Swing Equation. Determination of Transient Stability by Equal Area Criterion, Application of Equal Area Criterion, Critical Clearing Angle Calculation.- Solution of Swing Equation: Point-by-Point Method. Methods to improve Stability - Application of Auto Reclosing and Fast Operating Circuit Breakers.

7.3.4.2 SYLLABUS – GATE

UNIT-I Not covered.

UNIT-IINot covered.

UNIT-IIIState load flow equations- Load flow solution using Gauss-Seidal Method.

UNIT-IVNewton-Raphson method, Decoupled and Fast decoupled methods.

UNIT-V & VI Symmetrical components, analysis of symmetrical and unsymmetrical faults.

UNIT-VI & VIII Concept of system stability, swing curves and equal area criterion.

7.3.4.3 IES SYLLABUS

UNIT-I Not covered.

UNIT-IINot covered.

UNIT-IIIState load flow equations- Load flow solution using Gauss-Seidal Method.

UNIT-IVNewton-Raphson method, Decoupled and Fast decoupled methods.

UNIT-V & VI Symmetrical components, analysis of symmetrical and unsymmetrical faults.

UNIT-VI & VIII Concept of system stability, swing curves and equal area criterion.


TEXT BOOKS

T1 Computer Methods in Power System Analysis, Stagg, G.W. and A.H.EI – Abiad, McGraw Hill Publishing Company.

T2 Modern Power System Analysis, I.J. Nagrath & D.P. Kothari, 2nd Edn., Tata McGraw Hill Publishing Company.

T3 Power System Analysis by P.S.R. Murthy, B.S. Publications.

REFERENCE BOOKS

R1 Power System Analysis, T.K. Nagasarkar, M.S.SukhijaR2 Power Systems Analysis, Hadi Sadat, TMHR3 Computer Modelling of Electrical Power Systems, J.Arrillaga, N.R.Watson.

7.3.6 WEBSITES

1. www.sonton.ac.uk (university of southampton)2. www.berkely.edu (University of California, Berkely)3. www.ncsu.edu (North Carolina University)4. www.manchester.ac.uk (University of Manchester)5. www.unb.ca (University of New Brun Swick)6. www.umn.edu (University of Minnesota)7. www.iitb.ac.in (IIT, Bombay)8. www.iitk.ac.in (IIT, Kanpur)9. www.iitm.ac.in (IIT, Madras)10. www.iitd.ac.in (IIT, Delhi)11. www.iitkgp.ac.in (IIT, Kharagpur)12. www.iitc.ac.in (IIT, Calcutta)13. www.iisc.ernet.in (IISc, Bangalore)14. www.nit.ernet.in (NIT, Warangal)15. www.bits-pilani.ac.in 16. www.annauniv.edu (Anna University, Chennai)17. www.iitr.ernet.in (IIT, Roorkee)18. www.rangoli.rect.ernet.in (REC, Trichy)19. www.ieee.com20. www.ieeecsss.org21. www.ece.uiuc.edu22. www.see.ed.ac.uk

23. www.amazon.com24. server.oersted.dtu.dk25. www.ecse.rpi.edu26. www.alibris.com


REGIONAL 1. Name : Prof. M Sydulu

Designation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering

NIT-Warangal – 506004.Phone number : +91-870-2431616(O)e-mail : [email protected]

2. Name : Prof..D.M.Vinod KumarDesignation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering

NIT-Warangal – 506004.Phone number : +91-870-2431616(O)e-mail : dvmk @nitw.ac.in

3. Name : Dr. Bhagwan K.MurthyDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering


4. Name : V.T. SomashekharDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering

NIT-Warangal – 506004.Phone number : +91-870-2453416 (O) e-mail : [email protected], [email protected]

5. Name : Dr. A.D.RajkumarDesignation : ProfessorDepartment : Electrical EngineeringOffice Address : Department of Electrical Engineering

University College of EngineeringOsmania University, Hyderabad-500007

Phone number : +91-040-27682382 (O)e-mail : [email protected]

6. Name : Dr. M. VijayakumarDesignation : Associate ProfessorDepartment : Electrical EngineeringOffice Address : Department of Electrical Engineering

JNTU College of Engineering, Ananthapur, A.Pe-mail : www.jntu.ac.in

7. Name : Prof. Shankarram

Designation : ProfessorDepartment : Department of Electrical EngineeringOffice Address : JNTU College of Engineering, Kukatpally, Hyderabade-mail : www.jntu.ac.in

NATIONAL


Dy. Director (Administration.), IIT - Delhi, Hauzkhas, New Delhi - 110016.Phone number : +91-11-26591250 (O) , Fax : 91-11-26862037,e-mail : [email protected]

[email protected]

2. Name : Dr. S.V. Kulkarni,Designation : Associate Professor,Department : Electrical and Electronics EngineeringOffice address : IITBombay, Powai, Mumbai - 400076, India,Phone number : +91- 22-25671098,e-mail : [email protected]


Office Address : Room No. II/211, IIT Delhi Phone number : +91 11 2659 1094 ,91 11 2659 1886

email : [email protected]

4. Name : Dr. Sivaji ChakravortiDesignation : Professor,Department : Electrical and Electronics engineering

Jadavpur University, Kolkatta - 700032, Indiaemail : [email protected], [email protected]

INTERNATIONAL


Department : School of Electrical EngineeringOffice address : Georgia Institute of Technology, USA.Phone NumberE-mail : [email protected]

2. Name : Dr. Clayton R Paul, Designation : ProfessorDepartment : Electrical and Computer Engineering,Office : School of Engineering, Mercer University, Macom,Georgia-31207,Phone Number : (912) 301-2213,Website : www.faculty.mercer.paul_cr


Department : Dept. of Electrical EngineeringOffice address : Ira A.Fulton School of Engineering, Arizona State University.

Tempe, AZPhone Number : 85287-7206E-mail : Jushan Zhang @ee.gatech.edu

4. Name : Dr. Edward Wai-chau Lo, Designation : Honorary Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice address : Department of Electrical and Electronics Engineering

University of Hongkong, Hongkong.Phone Number :Email : [email protected]

5.4.8 JOURNALS


2. Name of the Journal : IEEE Transactions on Power SystemsPublisher : IEEE Publications

3. Name of the Journal : IEE Proceedings: Part-C[Generation, Transmission & Distribution]Publisher : IEEE Publications











1. Title : Continuous Newton's Method for Power Flow Analysis Author : Milano, F.Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 50-57

2. Title : Distributed Transient Stability Simulation of Power Systems Based on a Jacobian-Free Newton-GMRES Method

Author : Ying Chen; Chen Shen; Jian WangJournal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 146-156



3. Title : Decentralized Optimal Power Flow Control for Overlapping Areas in Power Systems

Author : Hug-Glanzmann, G.; Andersson, G.Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 327-336

4. Title : A Study on the Effect of Generation Shedding to Total Transfer Capability by Means of Transient Stability Constrained Optimal Power Flow

Author : Hakim, L.; Kubokawa, J.; Yue Yuan; Mitani, T.; Zoka, Y.; Yorino, N.; Niwa, Y.; Shimomura, K.; Takeuchi, A.

Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 347-355

5. Title : Unit Commitment With Probabilistic Spinning Reserve and Interruptible Load Considerations

Author : Aminifar, F.; Fotuhi-Firuzabad, M.; Shahidehpour, M.Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 388-397

6. Title : Optimal Capacitor Allocation in a Distribution System Considering Operation Costs

Author : Jong-Young Park; Jin-Man Sohn; Jong-Keun ParkJournal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 462-468

7. Title : Reliability Evaluation for Distribution System With Renewable Distributed Generation During Islanded Mode of Operation

Author : Atwa, Y. M.; El-Saadany, E. F.Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 572-581

8. Title : Distribution Transformer Losses Evaluation: A New Analytical Methodology and Artificial Neural Network Approach

Author : Leal, A. G.; Jardini, J. A.; Magrini, L. C.; Ahn, S. U.Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : May 2009,Volume: 24, Issue: 1, Page(s): 705-712







7.3.10 SESSION PLAN

Sl.No.

Topics in JNTU Syllabus

Modules and Sub ModulesLecture


UNIT – I – POWER SYSTEM NETWORK MATRICES – 1 (No. of Lectures – 09)

1Introduction to subject

Introduction to subject L1T1-Ch1 (P:1-5)T3-Ch1 (P:1-5)

2 Graph Theory Definitions L2 T1-Ch3 (P:28-30)

GATE

3 Incidence matrices

Element node incidence matrix, bus incidence matrix, branch path incidence matrix

L3T1-Ch3 (P:28-34)T3-Ch3 (P:17-20)R1-Ch6 (P:218-220)

Basic cut-set incidence matrix, augmented cut-set incidence matrix, basic loop incidence matrix, augmented loop incidence matrix

L4

T1-Ch3 (P:28-42)T3-Ch3 (P:20-24)R1-Ch6 (P:218-220)R2-Ch9 (P:34-75)

4 Y-Bus formation

Singular transformationL5L6


Non-singular transformationL7L8


5 Numerical problems Numerical problems L9


GATE

UNIT – II – POWER SYSTEM NETWORK MATRICES – 2 (No. of Lectures – 07)

6 Formation of Z-bus Introduction L10


7Algorithm for formation of bus impedance matrix

Addition of branchL11L12

T1-Ch4 (P:81-85)T3-Ch3 (P:81-85)R2-Ch9 (P:369-372)

Addition of linkL13L14

T1-Ch4 (P:85-89)T3-Ch4 (P:60-66)R2-Ch9 (P:372-375)

8 Modification of Z-bus

Modification of Z-bus L15 T1-Ch4 (P:89-92)T3-Ch4 (P:66-69)R1-Ch6 (P:249-256)R2-Ch9 (P:375-377)

9 Numerical problems Numerical problems L16

T1-Ch4 (P:92-104) T3-Ch3 (P:70-96)R1-Ch6 (P:256-258)R2-Ch9 (P:377-381)

UNIT – III – POWER FLOW STUDIES – 1 (No. of Lectures – 08)

10Necessity-Data for power flow studies

Introduction to Load flow studies-advantagesData required for LFS

L17

T2-Ch6 (P:184-188)T3-Ch5 (P:98-101)R1-Ch4 (P:81-83)R1-Ch7 (P:266-268)R2-Ch9 (P:189-195)R3-Ch4 (P:81-86)

GATEIES

11State load flow equations

Power flow equations L18

T2-Ch6 (P:196-204)T3-Ch5 (P:101-105)R1-Ch7 (P:268-276)R2-Ch6 (P:208-209)R3-Ch4 (P:86-87)

12Load flow solution using Gauss-Seidal Method-flowchart

Introduction to Gauss-Seidal methodGauss-Seidal Power flow solution

L19


Problem L20T2-Ch6 (P:209-212)R1-Ch7 (P:278-281)R2-Ch6 (P:213-220)

Algorithm and Flowchart for LFS using Gauss-Seidal method

L21T2-Ch6 (P:205-209)T3-Ch5 (P:108-109)R2-Ch6 (P:213-220)

13 Acceleration factorImproving rate of convergence using acceleration factor

L22


14LFS with and without PV buses

Algorithm modification when PV buses are also present

L23T2-Ch6 (P:207-212)T3-Ch5 (P:105-109)R1-Ch7 (P:283-289)R2-Ch6 (P:209-212)

Problem without PV bus, Problem with PV bus

L24

UNIT – IV – POWER FLOW STUDIES – 2 (No. of Lectures – 11)

15 Newton-Raphson method in polar and Rectangular co-ordinates-flowcharts

Introduction to NR method L25


GATEIES

NR power flow solution in Polar Co-ordinates

L26 T2-Ch6 (P:214-218)T3-Ch5 (P:112-115)R1-Ch7 (P:296-298)R2-Ch6 (P:232-235)R3-Ch4 (P:89-94)

NR Algorithm and flowchart for LFS in Polar Co-ordinatesProblem

L27L28


NR power flow solution in Rectangular co-ordinates

L29


NR Algorithm and flowchart for LFS in Rectangular coordinates

L30

T2-Ch6 (P:221-222)R1-Ch7 (P:300-301)R2-Ch6 (P:201-208)R3-Ch4 (P:89-98)

16Representation of PV buses

Algorithm modification when PV buses are also present

L31


Problem without PV busProblem with PV bus

L32


17Decoupled and Fast decoupled methods

Decoupled LFS and fast decoupled LFS

L33


FDLF Algorithm and flowchart for LFS, Problem

L34


18Comparison of different methods

Comparison of load flow studies L35


UNIT – V – SHORT CIRCUIT ANALYSIS – 1 (No. of Lectures – 05)

19 Per unit systemRepresentation per unit equivalent reactance network of 3-phase power system, Problems

L36L37


GATEIES

20 Symmetrical fault analysis

Short circuit current and MVA calculation

L38 T2-Ch4 (P:99-125)T2-Ch4 (P:327-329)


Fault level calculations L39

Applications of series reactor L40

UNIT – VI – SHORT CIRCUIT ANALYSIS – 2 (No. of Lectures – 08)

21Symmetrical component theory

Representation of positive, negative and zero sequence of a given power system components

L41

T2-Ch10 (P:369-370)T3-Ch7 (P:217-221)

R1-Ch10 (P:381-385)R2-Ch10 (P:399-405)

GATEIES

22 Sequence networksRepresentation of positive, negative and zero sequence of a given network

L42T2-Ch10 (P:370-390)R1-Ch10 (P:385-397)R2-Ch6 (P:406-432)

23Unsymmetrical fault analysis (LG,LL,LLG faults) using Z bus

Introduction to Unsymmetrical faults and symmetrical components

L43

T2-Ch11 (P:397-399)T3-Ch7 (P:219-224)

R1-Ch10 (P:398-399)R2-Ch10 (P:432)

Sequence impedance of Y-connected loads and transmission lines

L44

T2-Ch10 (P:377-380)T3-Ch7 (P:214-225)

R1-Ch10 (P:388-395)R2-Ch10 (P:407-410)

Sequence impedance of synchronous machine and transformer

L45

T2-Ch10 (P:381-389)T3-Ch7 (P:227-231)

R1-Ch10 (P:389-394)R2-Ch10 (P:410-414)

Sequence network of loaded generator, Problem

L46

T2-Ch10 (P:386-393)T3-Ch7 (P:226-227)

R1-Ch10 (P:394-396)R2-Ch10 (P:418-420)

LG fault analysis using symmetrical components

L47

T2-Ch11 (P:398-402)T3-Ch7 (P:231-235)

R1-Ch10 (P:399-406)R2-Ch10 (P:421-422)

LL and LLG fault analysis using symmetrical components

L48

T2-Ch11 (P:402-414) T3-Ch7 (P:235-244)

R1-Ch10 (P:406-413)R2-Ch10 (P:423-432)

UNIT – VII – POWER SYSTEM STEADY STATE STABILITY ANALYSIS (No. of Lectures – 04)

24

Elementary idea of steady state, Dynamic and Transient stabilities

Modes of operation of power systems L49

T2-Ch12 (P:42-435)T3-Ch8 (P:257-263)

R1-Ch11 (P:433-435)R2-Ch11 (P:460-461)

GATEIES

25 Power angle curve Dynamics of a synchronous machinePower angle curve

L50 T2-Ch12 (P:435-444)T3-Ch8 (P:260-262)

R1-Ch11 (P:440-448)R2-Ch11 (P:464-469)

Problem L51T2-Ch12 (P:444-454)R1-Ch11 (P:449-451)R2-Ch11 (P:469-471)

26Determination of steady state stability

Calculation of steady state stability limit and synchronizing coefficient

L52

T2-Ch12 (P:454-460)T3-Ch8 (P:260-262)

R1-Ch11 (P:472-476)R2-Ch11 (P:471-476)

UNIT – VIII – POWER SYSTEM TRANSIENT STATE STABILITY ANALYSIS (No. of Lectures – 07)

27Determination of transient stability by equal area criterion

Application to sudden increase in power input

L53

T1-Ch10 (P:365-369)T2-Ch12 (P:459-465)T3-Ch8 (P:262-269)

R1-Ch11 (P:443-446)R2-Ch11 (P:486-490)

GATEIES28

Critical clearing angle calculation

Effect of clearing time on stability, Problems

L54

T2-Ch12 (P:466-470)T3-Ch8 (P:269-274)

R1-Ch11 (P:447-451)R2-Ch11 (P:492-497)

Sudden loss of one of parallel lines L55T2-Ch12 (P:468-470)T3-Ch8 (P:274-276)

R1-Ch11 (P:451-453)

Sudden short circuit on one of parallel lines- calculation of t

c and

critical clearing anglea) at the sending endb) at the receiving end

L56

T2-Ch12 (P:470-475)T3-Ch8 (P:274-280)

R1-Ch11 (P:492-504)R2-Ch11 (P:453-456)

29

Methods of improving stability-Auto reclosing circuit breakers

Methods of improving stability-Auto reclosing circuit breakers

L57

T2-Ch12 (P:470-475)T3-Ch8 (P:277-284)

R1-Ch11 (P:478-482)R2-Ch11 (P:492-510)

30Simulation of swing equation using numerical methods

Numerical solution of swing equation by point by point method

L58T2-Ch12 (P:480-505)T3-Ch8 (P:277-303)

R1-Ch11 (P:457-467)R2-Ch11 (P:504-510)

Problem L59


UNIT – I1. Form the network matrices Zloop using non-singular transformation for the network connections:

ELEMENT P-R1 1-2 (1)2 1-2(2)3 1-34 2-45 3-5

SelfBus code Impedance1-2 0.61-3 0.53-4 0.51-2(2) 0.42-4 0.2

MutualBus code Impedance1-2(1) 0.11-2(1) 0.2 (JNTU May 09)

2. Prove Ybr =KYbusK’ using non-singular transformation? (JNTU May 09)

3. What is primitive network matrix and represent its forms? Prove Y bus =At[y]A using singular transformation? (JNTU Nov 08)

4. Form Ybus for the network by direct inspection method: Element Positive sequence reactanceE-A 0.04E-B 0.05A-B 0.04B-C 0.03A-D 0.02C-F 0.07D-F 0.10 (JNTU May 09)

5. Form the Ybus for the given network: Element Positive sequence reactance1-2 j1.02-3 j0.42-4 j0.23-4 j0.23-1 j0.84-5 j0.08

6. i. What do you understand by “branch-path incidence matrix K”? And what are the elements of the matrix K? And what is the nature of this matrix? What is the relation between the branch-path incidence matrix K and the submatrix A

b of the bus incidence matrix A, (A

b is of dimensions b × (n-l).

ii. Taking node ‘O’ as the reference, write down the branch-path incidence matrix K for the Figure 1 given below. (Take 1-2-3-5 as tree).

(JNTU Sep 06)

7. i. Define the following terms with suitable examples each: a. Basic Cutset Incidence Matrix b. Basic Loop Incidence Matrixc. Branch Patch incidence Matrixd. Node incidence Matrix.e. Augmented Basic Cutset incidence matrix.

ii. Derive the relationship between loop impedance matrix, primitive network impedance matrix and Basic loop incidence matrix. (JNTU Aug 06, Apr 05, 04, Dec 02)

8. i. Deduce an expression for the formation of YBus

using singular transformation y. YBus

=AtyA where y is

the primitive admittance matrix.

ii. Derive the expression for Bus admittance and impedance matrices by singular transformation.(JNTU Aug 06, Nov 03, Apr 06, 05, 04, 03, 02, 01)

9. Derive an expression for Zloop

for the oriented graph shown below

(JNTU Aug 06, Apr 05, 04, 03, Nov 03)

10. i. For the network shown below, draw its graph and mark also a tree. Give the total number of edges (i.e. elements), nodes, buses and branches for this graph. Write also its nodal equations and determine the elements of Y

Bus matrix directly by inspection.

ii. For the same network, write the loop equations and hence determine the elements of Zloop

matrix directly by inspection. Values shown are currents and admittances.

(JNTU Aug, Apr 06, Nov 03)

11. For the network shown in figure below, draw its graph and mark a tree.How many trees will this graph have? Mark the basic cut sets and basic loops and form the bus incidence matrix A, Branch path incidence matrix K and also the basic loop incidence matrix.

(JNTU Aug 06, Apr 06, 05, 03)

12. i. Define the following terms with suitable example: Basica tree b. branches c. Links d. co-tree e. loop.

ii. Write the relation among the number of nodes, number of branches, number of links and number of elements.

iii. For the graph given in figure below, draw the tree and the corresponding co-tree. Choose a tree of your choice, and hence write the cutest schedule.

(JNTU Apr 04, 03)

13. i. For the power system network shown in figure below, draw thea. Oriented graph b. Tree and co-tree of the corresponding graph also show the basic/1oops and basic cut sets for the same.

(JNTU Apr 06)ii Hence write down the basic cut set incidence matrix.

14. Write abouti. Oriented graph and relevent matricesii. Cut-set schedule and tie set schedule (JNTU Apr 06, 01)

15. For the given network, draw the graph and ai. Tree write cut set schedule for a choosen tree branch voltages set.

ii. The incidence matrix is given below as : (JNTU Apr 05, 01)Branches 1 2 3 4 5 6 7 8

Draw oriented graph.16. Derive the relationship between bus admittance matrix, bus incidence matrix and primitive admittance

matrix. (JNTU Apr 05, 04, 3, Dec 02, IES 00 )

17. For the sample network shown in figure below, formThe incidence matrices A^, A, K, B, B^, C and C^ and verify the followingi. AbKt = Uii. Bl = Al Ktiii. C^ Bt = U

(JNTU May 05, Nov, Apr 03)

Retain node 1 as the reference, and take 1,2,5 as tree

18. For the graph shown in figure below selecting tree T (2,4,5,6)i. Write the fundamental loop matrix C and the fundamental cut set matrix B. Verify the relation

BCT = 0 and Cb = -B1t.ii. Write the augmented incidence matrix and incidence matrix A, by choosing (4) as reference node.

Arranging matrix A as [Ab:A1] corresponding to the tree T(2,4,5,6) and verify B1 = - Ab-1A1.

(JNTU Apr 05, Nov 03)

19. For the given Network draw the graph and tree. Write the cut set schedule, for a chosen tree branch set.(JNTU Apr 05)

20. Select for the sample shown below a tree. Retain node 1 as the reference and form the network matrices Y

bus and Z

loop by singular transformations. (JNTU Apr 04, 01)

Self MutualElement number Bus Code Impedance Bus Code Impedance

p-q Zpq, pq r-s Zpq, rs1 1-2(1) 0.62 1-3 0.5 1-2(1) 0.13 3-4 0.54 1-2(2) 0.4 1-2(1) 0.25 2-4 0.2

The impedance data for the sample network is given in the table below :

21. i. Explain the following terms.a. Basic loops b. cut-set c. basic cut-set d. loopby taking an oriented connected graph. What is the relation between basic loop and link and basic-cut-set and the number of basic cut-sets and the number of branches.

ii. Show the basic loops and the basic cut sets of the graph shown below and verify the relation asked in (i). (Take 1 -2 -3 -4 as tree) (JNTU Apr 04, 03)

22. i. What is the element node incidence matrix Ã? And what are the elements of this matrix? What is the dimensions of this matrix Ã?

ii. What is bus-incidence matrix A? and what is the dimensions of this matrix?iii. For the graph shown below, write down A and Ã matrices. (Take 1-2-3-4 as tree) (JNTU Apr 04)

23. i. The rows of the bus incidence matrix A are arranged according to a particular tree and the matrix A is partitioned into sub matrices Ab of dimension bx( n-l) and A1 of dimensions lx(n-l) , where the rows of Ab correspond to branches and rows of A1 correspond to links. Show the above partitions for the matrix A, for the following sample network. Also form the element node incidence matrix Ã.

ii. For the oriented connected graph obtain the Bus incidence matrix A, Branch path incidence matrix K

and basic cut-set matrix B (JNTU Apr 04)

24. For the system shown in figure below, form the bus incidence matrix A and Branch path incidence

matrix K and also predetermine the basic cut set incidence matrix B and the basic loop incidence matrix C and hence show that (i) Abkt = U, (ii) Bl = Alkt. Take 1, 5, 4 as tree (JNTU Nov 03)

25. The positive sequence reactances for the network shown in figure below is given in table. Designate the elements A- B, and D - F as inks and node G as the references bus Form

i. The incidence matrices ii. The network matrices Y

Bus, Y

Br and Z

loop by singular transformations (JNTU Nov 03)

Positive sequence reactances of sample network.

Element ReactanceG-A 0.04G-B 0.05A-B 0.04B-C 0.03A-D 0.02C-F 0.07D-F 0.10

26. i. What does basic loop incidence matrix C represent? What are the entries of this matrix and how are they determined?

ii. Explain briefly about Augmented loop incidence matrix . (JNTU Apr 03)iii. Obtain oriented connected graph for the given power network shown below. Hence obtain the C and .

27. For the following graph, form the necessary incidence matrices and hence verify the following relations: a. Ab Kt=U b. Bl=Al Kt c. Cb=-Blt d.

Assume spanning tree consisting of the elements 1, 2, 4. (JNTU Dec 02)

28. The transpose of the bus incidence matrix of a power system network is given by

i. Draw its oriented graphii. Obtain B, matrices iii. Prove the following relations: (JNTU Dec 02)

a. b. c. d.

29. Define the incidence matrices and verify the following relations for the

network shown in fig.1. Take 1 as ground bus

a. b. c. d. (JNTU Dec

02)

30. Write short notes on:i. Z

Loop matrix

ii. Types of frames of references and their performance equations. (JNTU Dec 02)

31. i. Prove that ZBus

= KTZBRK

. (JNTU Mar 02, Dec 02, 01)ii. Determine Z

Loop for the following network using Basic loop incidence matrix.

32. For the system shown in fig.1. form Bus incidence matrix A and branch path incidence matrix K and also predetermine basic cut-set incidence matrix C from A and K matrix. Take 1, 2, 3 as tree.

(JNTU Nov 01)

33. Obtain the oriented graph of the network whose fundamental cut-set matrix is given below :Twigs Links (JNTU Nov 01)

34. i. Derive loop admittance matrix from the augmented admittance matrix Y^BR (JNTU Nov 01)ii. For the network shown in Fig. 3 obtain Zbus = Kt ZBR K by non singular transformations.

35. Consider the system shown in figure below. It shows a transmission network with series reactances of lines shown in fig. The line charging and shunt admittances are neglected

i. By choosing appropriate tree for the graph write for B and C matrices. Write the incidence matrix A with (6) as reference node

ii. Very BCT = 0 and deduce the fundamental cut set matrix form the matrix A.iii. Compute Y

Bus matrix with ground as reference (JNTU Nov 00)

36. i. Find bus impedance matrix for the system whose reactance diagram is shown in fig. All impedances are in p.u.

ii. Explain briefly about bus incidence matrix with an illustration. (JNTU Dec 04)

37. For the Y-bus matrix of a 4-bus system given in per unit, the buses having shunt elements are

a. 3 and 4 b. 2 and 3 c. 1 and 2 d. 1,2 and 4 (GATE 09)

38. Fig. below shows a d.c. resistive network and its graph is drawn aside. A ‘proper tree’ chosen for analysing the network will contain the edges. (GATE 94)a) ab, bc, ad b) ab, bc, ca c) ab, bd, cd d) ac, bd, ab

39. The positive and zero sequence impedance data for the sample power system shown in figure is given in table below. For this sytem.

i. Draw the positive sequence diagram and oriented connected graph.ii. Neglecting resistance, from positive sequence network matrices Ybus, Zbus, YBR, ZBR, Zloop and

Yloop by singular transformations.iii. Repeat (ii) using non singular transformationsiv. Repeat (iii) including resistance.

Element Positive sequenceZero Sequence Element Mutual ImpedanceImpedance Impedance

Generator A 0.0 + j 0.25 0.0 + j 0.1Generator B 0.0 + j 0.25 0.0 + j 0.1Generator C 0.0 + j 0.25 0.0 + j 0.1Line A-B 0.03 + j 0.13 0.08 + j 0.45Line B-C (N) 0.05 + j 0.22 0.13 + j 0.75 Line B-C (S) 0.08 + j 0.48Line B-C (S) 0.05 + j 0.22 0.13 + j 0.75

Line C-D 0.02 + j 0.11 0.07 + j 0.37

40. Using the relations between inter connected and primitive network variables prove followingi. A

bKt = U ii. B

l= A

lKt .

41. Derive the expression for branch admittance and branch impedance matrices by singular transformations. .

42. By non singular transformations show YBR = Y1

43. By using non singular transformations show the following. i. Z

BR = Z

1 - Z

2 Z

4-1 Z

3ii. Z

BR = A

b Z

bus A

bt

44. For the oriented graph shown in figure, select the tree T(6, 7, 1, 4, 5) write B, C matrices and verify BCT = 0. Write the incidence matrix A with 6 as reference node and derive B from A.

45. Consider the linear graph shown in figure which represents a 3 bus transmission system with all shunt admittances at a bus lumped together. Each transmission line has a series impedance of 0.02 + j 0.08 and a half line charging admittance of j 0.02. Zero is the ground bus.

a. Compute Ybus

and Zbus

analytically; b. Verify Zbus

Ybus

= U

46. The system impedance data for the system shown in figure is given in table below. Line 1-0 and 2-0 represent the transient reactances of the generators connected at buses 1 and 2 respectively.

From bus To bus R X1 4 0.15 0.601 5 0.05 0.202 3 0.05 0.202 4 0.10 0.402 5 0.05 0.203 4 0.10 0.401 0 - 0.252 0 - 1.25

47. For the oriented graph select the tree T (6, 7, 8, 9) and write B, C matrices,

Verity the orthogonomality choosing ground as Deference bus, write the matrix A.

UNIT – II

1. Write the algorithm for the formation of bus incidence matrix for a branch case and form the Zbus for the given network connections. Element Bus code Impedance1 1-2 0.22 1-4 0.43 2-3 0.4 (JNTU May 09)

2. a. Explain merits and demerits of building Zbus algorithm.b. Write step-by-step algorithm for Zbus building for a network containing no mutual and no phase shifting

transformers. (JNTU May 09)

3. Explain modification of the bus impedance matrix for changes in the network. (JNTU May 09)

4. Using the method of building algorithm find the bus incidence matrix for the network connection given:

Element Bus code impedance1 1-2 j0.22 2-3 j0.53 2-1 j0.154 3-1 j0.3 (JNTU May 09)

6. Derive expression for a partial network adding a link to form Zbus. (JNTU Nov 08)

7. Build Zbus for the 3-bus system connection given as: element bus code impedance

1 1-2 j0.12 1-2 j0.253 1-3 j0.14 2-3 j0.1 (JNTU Nov 08)

8. If an impedance of j1.5 pu is connected between bus-3 and ground of the network Z bus given below, compute the new Zbus(all values are in pu):

(JNTU Nov

08)

9. i. Derive the bus impedance matrix elements, when each element is added one by one into a partial network by considering (i) Adding a new element without creating a new bus. (ii) Adding a new element with creating a new bus. Assume mutual impedance between the added element and the elements in the partial network.

ii. Develop the model of a phase shifting transformer deriving necessary expressions.(JNTU Sep 06, Dec 02, 01)

10. Form YBus

using singular transformation for the network shown. (JNTU Sep 06, Apr 04)

11. i. What is primitive network?ii. For the following network, write the network matrix Y

Bus by singular transformation. The impedances

are given in figure are in p.u. (JNTU Sep 06, Apr 04)

12. Describe the procedure of modification of existing Zbus

by adding branch from new bus (p) to ref node, from new bus (p) to existing bus (k) , form existing bus (k) to ref node and between existing buses (j) and (k). (JNTU Sep, Apr 06, 03, Nov 03)

13. Describe the method of Ybus

formation by direct inspection and by singular transformation. Bring out the advantages of Y

bus over Z

bus with suitable examples.(JNTU Sep 06, Nov 03, Mar 02, Dec 02)

14. What are the advantages of Zbus

building algorithm? Explain what is primitive network, primitive admittance matrix and primitive impedance matrix. Explain by giving an example.

(JNTU Sep 06, Apr 03)

15. i. Write a detail note on tap-changing and regulating transformer. ii. Explain the necessity of transformer modelling for power system studies.(JNTU Apr 06, Nov 03)

16. Figure shows the one line diagram of a 4-bus system. Impedances in p.u. are indicated in the figure. i. Find Y

Bus assuming that the line shown dotted is not connected

ii. What modifications need to be carried out in YBus

if the line shown dotted is connected.(JNTU Apr 06, 05, 04, 03)

17. Describe the procedure of modification of Zbus

by adding mutually coupled branch from existing buses (p) and (k). (JNTU Apr 06)

18. i. Two branches connected between buses 2-3 and 3-1 having impedances equal to j0.25 pu are coupled through mutual impedance Zm = j0.15 pu. Find the nodal admittance matrix for the mutually coupled branches and write the corresponding nodal admittance equations.

ii. What is primitive admittance and impedance matrix. Bring out the significance of system admittance matrix. (JNTU Apr 06)

19. i. Explain why often use Bus admittance matrix rather Bus impedance matrix in the load flow studies.ii. Figure 2 shows the singe line diagram of a simple 4-Bus system. Table gives the line impedances

identified by the busses on which these terminate. The shunt admittances at all busses is assumed negligible. (JNTU Apr 06)a. Find Y

Bus assuming the line shown dotted is not connected

b. What modifications need to be carried out in YBus

if the line shown dotted is connected.

20. Write short notes on: Modelling of off-nominal transformer settings. (JNTU May 05, Dec 02, Mar 02)

21. How bus impedance matrix is developed by step by step method? Describe the method with algorithm.(JNTU Apr 05, 04, 03, 01, Nov 03)

22. Impedances connected between various buses are as follows:X

10 = j1.25, X

30 =j1.25, X

12= j0.25, X

23 = j0.4, X

24 = j0.125, X

43 = j0.2, where ‘0’ is reference node. All

impedances are in pu. Determine bus impedance matrix for the network connecting above impedances. Preserve all buses. (JNTU Apr 05, Nov 03)

23. Discuss the method of modelling a phase shifting transformer in load flow studies. Derive relevant equations that are necessary to modify the elements of Y

Bus. (JNTU Apr 05, Nov 03, 01)

24. Find the Y Bus using singular transformation for the system shown in figure below

and Y = dia [ Y10

Y20

Y30

Y40

Y34

Y23

Y12

Y24

Y13

] (JNTU Apr 05, 04, 03)

25. Describe the procedure of modification of Z bus by adding and removing the coupling branch from existing bus (p) to new bus (q) and from existing bus (p) to reference. (JNTU Apr 05)

26. Describe the procedure of modification of Z bus by adding mutually coupled branch from existing bus (p) to new bus (q) and by removing the same from existing bus (p) and (k). (JNTU Apr 05)

27. i. Two branches connected between buses 2-3 and 3-1 having impedances equal to j0.25 pu are coupled through mutual impedance Z

m = j0.15 pu. Find the nodal admittance matrix for the mutually coupled

branches and write the corresponding nodal admittance equations.ii. What is primitive admittance and impedance matrix. Bring out the significance of system admittance

matrix. (JNTU Apr 05)

28. i. Prove that when there is no mutual coupling, the diagonal and off-diagonal elements of the admittance Y

Bus can be computed from

Yii = S

j Y

ij

and Yij = -Y

ijwhere Y

ij is the sum of the admittance of all the lines connecting buses i and j.

ii. Consider the linear graph shown below, which represents a 3-bus transmission system with all the shunt admittance lumped together. Each line has a series impedance of (0.02 + J0.08) and half line charging admittance of J0.02,a. Compute Y

Bus by inspection

b. Compute ZBus

analyticallyc. Verify Z

Bus YT

Bus = U. (JNTU Apr 04, 03, Mar 02)

29. A four bus power system is shown in figure given below:

i. Find the bus incidence matrix A for the four bus system shown in the figure. Take ground as reference. The reactances of generators are .2 p.u.

ii. Find also the primitive admittance matrix for the system. It is given that all the lines are characterized by a series impedance of 0.1 + j 0.7 ohm/km and a shunt admittance of j0.35 x 10-5 m mhos/km.

(JNTU Nov 04)30. Modify the impedance matrix for a network connecting following impedances to include the addition

of Zb = 0.25 pu connected between buses 1 and 4 so that it couples through mutual impedance j0.15 pu

to the branch impedance already connected between buses 1 and 2. Impedances of network are : X

10=X

30=j1.25, X

12=j0.25, X

23=j0.4, X

24=j0.125, X

43=j0.2 where ‘0’ is a reference node. All

impedances are in pu. (JNTU Apr 04)

31. i. Three bus system having reference node ‘4’, comprises the line impedances in pu as follows: Z

14 = j1.0, Z

12 = j0.2, Z

24 = j1.25, Z

23 = j0.05. Find Z

bus for the system by the Z

bus building algorithm.

ii. What are the features and merits of admittance matrix over the impedance matrix in solving the power system problems? (JNTU Apr 04)

32. Discuss the pie (p) – mathematical modelling of off-nominal tap ratio transformer of figures (1) and (2). (JNTU Apr 03, Dec 02)

33. i. Explain representation of an element in admittance form and impedance form. ii. For the system shown below, form Y

Bus. (JNTU Apr 03)

(1)

(2)

(3)

j0.2 j0.2 j0.5

j0.15 j0.15 j0.1

34. For the system shown in figure, obtain YBus

by direct inspection method. Take bus(1) as references. The element impedances are indicated in p.u. (JNTU Apr 03)

(1) (3)

(2)

j0.1

j0.4

j0.5

35. i. Derive the expression for elements of modified bus impedance matrix when a mutually coupled element is to be removed. (JNTU Apr 03)

ii. The ZBus

matrix of a power system network is given by:

choosing bus 3 as reference bus, the network is shown in fig. Modify the elements of ZBus

matrix by removing the line between the buses 3 and 4 (JNTU Dec 02)

36. Consider that for a given network Z bus has been formulated upto a certain stage, now explain the z bus building algorithm for the following modifications.

i. A new branch is connected between the oldbus to the reference busii. A new branch is connected between two old busses.iii. A new branch is connected between two new busses. (JNTU Nov 02)

37. Consider that for a given network Z bus has been formulated upto a certain stage, now explain the Z bus building Algorithm for the following modifications.

i. A new branch is added from a new bus to the reference.ii. A new branch is added from a new bus to an old bus. (JNTU Nov 02)

38. i. Form the Y Bus using singular transformation for the network shown in Fig.

ii. A power system consists of 4 buses. Generators are connected at buses 1 and 3, whose reactances are j

0.2 and j 0.1 respectively. The transmission lines are connected between buses 1-2, 1-4, 2-3 and 3-4 have reactances of j 0.25, j 0.5, j 0.4, j 0.1 respectively. Find the bus admittance matrix (i) by direct inspection. (ii) using bus incidence matrix and primitive admittance matrix. (JNTU Dec 02)

39. A three bus system has a transmission line each between a pair of buses. The reactances of lines between buses 1-2, 1-3, and 2-3 respectively are j 0.2, j 0.4, j 0.4 respectively. There is a mutual impedance between the elements 1-3 and 2-3 having a value of j 0.1. Determine the bus impedance matrix, by adding elements one by one. (JNTU Dec 02)

40. Find the bus admittance matrix using singular transformation matrix for the following network:

Derive the formula used. (JNTU Dec 02)

41. Compute the bus admittance matrix for the power system shown in fig., (i) by direct inspection method (ii) using singular transformation matrix. Derive formulae used. (JNTU Dec 02)

42. Determine the bus impedance matrix for the system shown in fig. by adding element by element. Take

bus 1 as reference bus. Determine the bus impedance matrix for the system shown in fig. by adding element by element. Take bus 1 as reference bus. (JNTU Dec 02)

43. i. Zbus

for the system shown, is given below using ground as reference

If a second transmission line TL2, which has a self impedance of 0.2 and a mutual of 0.1 with TL1 is added form Z

bus.

ii. If a newly added transmission line TL2 is removed, form the resultant Zbus

(Data : each generator : 0.25each transmission line : self of 0.2and mutual : 0.1) (JNTU Jan 01)

44. Using the building algorithm, construct the bus impedance matrix Zbus

for the network shown below. Choose 3 as the reference bus. The system data is given below :

Mutual coupling between 2-4(1) and 2-4(2) may be taken as 0.1. (JNTU Jan 01)

45. Form Zbus

for the network shown in fig. All values on P.U. (JNTU Jan 01)

46. Write short notes on:i. Phase shifting transformerii. Removal of a link in Z

Bus with no mutual coupling between the element deleted and other elements in

the network. (JNTU Jan 01)

47. A 3 bus network is shown in fig. Determine BUS impedance matrix of the network matrix use of Z bus building algorithm. (JNTU Oct 02)

48. The network shown in the given figure has impedance in p.u. as indicated. The diagonal element Y22

of the bus admittance matrix Y

BUS of the network is (GATE 05)

a) - j 19.8 b) + j 20.0 c) + j 0.2 d) - j 19.95

49. The Z matrix of a 2-port network as given by

The element Y22 of the corresponding Y matrix of the same network is given by

a) 1.2 b) 0.4 c) -0.4 d) 1.8 (GATE 04)

50. The bus impedance matrix of a 4-bus power system is given by

A branch having an impedance of j0.2 Ohms is connected between bus 2 and the reference. Then the values of Z22,new and Z23,new of the bus impedance matrix of the modified network are respectively.a) j0.5408W and j0.4586W b) j0.1260W and j0.0956Wc) j0.5408W and j0.0956W d) j0.1260W and j0.1630W (GATE 03)

51. For the Y-bus matrix given in per unit values, where first, second, third and fourth row refers to bus 1, 2, 3 and 4 respectively, draw reactance diagram. (GATE 01)

52. For the network given below, obtain bus admittance matrix (Ybus

) using data given :

Lines between nodes Impedance P.U. Half of the charging Admittance1 - 2 0.0 + j 0.05 j 1.251 - 3 0.0 + j 0.02 j 0.52 - 3 0.0 + j 0.02 j 0.5

Shunt reactor at node Impedance1 - 2 0.0 + j 2.0 (GATE 98)

53. The single line diagram of a network is shown below. The hye series reactance is 0.001 PU per KM and shunt susceptance is 0.0016 PU per KM. Assemble the bus admittance matrix (Y

bus) of the

network, neglecting the line resistance. (GATE 94)

54. A sample power system network is shown in fig. The reactances marked are in p.u. The p.u. value of

Y22 of the Bus admittance Matrix (YBus) is (GATE 91)

i. j 10.0ii. j 0.4iii. - j 0.1iv. - j 20.0

55. Normally ZBus

matrix is a (IES 04)i. Null matrix ii. Sparse matrix iii. Full matrix iv. Unity matrix

56. The bus admittance matrix of a power system is given as (IES 03)

The impedance of line between bus 2 and 3 will be equal toi. + j 0.1 ii. - j 0.1 iii. + j 0.2 iv. - j 0.2

57.

In the network as shown above, the marked parameters are p.u. impedances. The bus-admittance matrix of the network is (IES 03)

i. ii.

iii. iv.

58. YBUS

as used in load flow study, and ZBUS

as used for short circuit study are : (IES 03)i. the same ii. inverse of each other iii. are not related to each other

59. The YBUS matrix of a 100-bus interconnected system is 90% sparse. Hence the number of transmission lines in the system must bei. 450 ii. 500 iii. 900 iv. 1000 (IES 02)

60. Draw the reactance diagram of the system whose bus admittance matrix is given below. First, second, third and fourth rows refer to buses 1, 2, 3, 4 respectively.

(IES 01)

61. Compute bus admittance matrix, primitive admittance matrix, and bus incidence matrix in a 3-bus power system.Bus Code Admittance1 - ground y12 - ground y23 - ground y31 - 2 Y42 - 3 Y53 - 1 Y6Y4, Y5, Y6 are mutually compled with each others. (IES 00)

62. For the power system with the following line data compute the bus admittance matrix with four digit accuracy.Bus-code Line Impedance HLCA Off nominal trans ratio1 - 2 0.05 + j 0.12 j 0.025 -2 - 3 0.0 + j 0.4 - 1.053 - 4 0.075 + j 0.25 j 0.02 -4 - 3 0.045 + j 0.45 j 0.015 -1 - 4 0.015 + j 0.05 - - (IES 99)

63. A power system network consists of three elements 0 - 1, 1 - 2 and 2 - 0 of per unit impedances 0.2, 0.4 and 0.4 respectively. Its bus impedance matrix is given by (IES 97)

a) b)

c) d)

64. Discuss the advantages of using YBUS model of power system network for load-flow analysis. (IES 97)

65. Consider the network shown in the following figure : (IES 96)The bus numbers and impedances are marked. The bus impedance matrix of the network is

a) b)

c) d)

66. The bus admittance matrix of the network shown in the given figure, for which the marked parameters are per unit impedance, is (IES 95)

a) b) c) d)

UNIT – III

1. a. Give classification of buses in load flow studies.b. What is slack bus? How do you select a slack bus in a given system? (JNTU May 09)

2. Why direct simulation of load flow is not possible? and mention data required for load flow solution?(JNTU May 09)

3. The YBus of a 5-bus system is (5×5)matrix. The system has an off nominal tap ratio transformer between buses 3 and 5 as shown in figure 3 if the transformer outage takes place, how are the Y BUS

elements are modified. (JNTU May 09)

4. Develop load flow equation suitable for solution by:a. Gauss-Seidel methodb. Newton-Raphson (Polar form) method using nodal admittance approach. (JNTU May 09)

5. Derive the basic equations for load flow studies and also write the assumptions and approximations to get the simple equations. (JNTU Nov 08)

6. The converged load flow solution is available how do you determine the slack bus complex power injection and system total loss? (JNTU Nov 08)

7. Explain modeling of transformer, transmission line, loads and generators for a load flow study. And derive general load flow equations. (JNTU Nov 08)

8. Write short notes on the following:i. Data for power flow studies.ii. Merits and demerits of using polar and rectangular coordinates in load flow studies.iii. Choice of Acceleration factors. (JNTU Feb 07)

9. The load flow data for the power system shown in figure is given in the following tables:

Bus code p - q Impedance Zpq1-2 0.08 + j0.241-3 0.02 + j0.062-3 0.06 + j0.18Generation Load

Bus code Assumed bus Megawatts Megavars Megawatts Megavarsvoltage

1 1.05 + j00 0 0 02 1.0 + j0 20 0 50 203 1.0 + j0 0 0 60 25

The voltage magnitude at bus 2 is to be maintained at 1.03 p.u. The maximum and minimum reactive power limits of the generator at bus 2 are 35 and 0 megavars respectively. With bus 1 as slack bus, obtain voltage at bus 3 using G. S. method after first iteration. (Assume Base Mva = 50)

(JNTU Feb 07, Nov 06, 04)

10. i. Explain the load flow solution using G-S method with the help of a flow chart. ii. How do you classify system variables in terms of state, input and output variables, in power flow

studies? (JNTU Feb 07, Nov, Mar 06, May 04)

11. i. What are acceleration factors? Explain their importance in power flow studies.ii. Describe load flow solution with P.V buses using G-S method.

(JNTU Nov 06, 05, May 04, 03)

12. Discuss the advantages and disadvantages of finding Ybus

byi. Singular transformation using graph theory.ii. Directly from the network.

Give illustration with necessary example. (JNTU Mar 06, May 04, 03)

13. i. The transmission line is a 230 KV, 200 km line having the following data. Find the Y-bus matrix for the two bus system. Express all values in p.u. on 230 K.V and 300 MVA bases.

R = 0.074 ohm/km; WL = 0.457 ohm/km; 0.277 x 106 ohm/km.

ii. Classify the various types of buses and explain the necessity of load flow studies.(JNTU Mar 06)

14. i. Draw flow chart for load flow solution by Gauss-Siedel iterative method using Ybus.

ii. What are the P- V buses? How are they handled in the above method. (JNTU Mar 06)

15. A 2-bus system has been shown in figure 1. Determine t he voltage at bus 2 by G.S method after 2 iterations.Y

21 = Y

22 = 1.6. / -800 p.u;

Y21

= Y12

= 1.9. / 1000 p.u;V

1 = 1.6. / 00. (JNTU Mar 06)

16. Write short notes on the following i. Data for power flow studies.ii. Merits and demerits of using polar and rectangular coordinates in load flow studies.iii. Choice of Acceleration factors. (JNTU Nov 05)

17. The data for 2-bus system is given below.S

G1 = unknown; S

D1 = unknown

V1 = 1.0 ∟00 p.u.; S1 = To be determined

SG2 = 0.25 + jQ

G2 p.u; SD

2 = 1 + j 0.5 p.u. The two buses are connected by a transmission line of p.u.

reactance of 0.5 p.u. Find Q2 and V2. Neglect shunt susceptance of the tie line. Assume |V2| = 1.0.

Perform two iterations using G. S. method. (JNTU Nov 05)

18. What is slack bus? Justify (JNTU May 05)

19. Consider the 3-bus system shown in figure. The p.u line reactances are indicated on the figure; the line resistances are negligible. The magnitude of all the 3-bus voltages are specified to be 1.0 p.u. The bus powers are specified in the following table.

Bus real demand reactive demand Real generation Reactive generation1 P

D1 = 1.0Q

D1 = 0.6 P

G1 = ? Q

G1(unspecified)

2 PD2

= 0 QD2

= 0 PG2

= 1.4QG2

(unspecified)3 P

D3 = 0 Q

D3 = 1.0 PG3 = 0 Q

G3(unspecified)

Carry out the load flow solution using G..S method upto one iteration, taking bus 1 as slact bus. (JNTU Nov 04)

20. i. How do you classify the buses in power system and what is its necessity. ii. Derive static load flow equations. (JNTU May 04, 02, Nov 02)

21. i. How do you formulate power flow problem.ii. How do you classify system variables in terms of state, input and output variables, in power flow

studies. (JNTU May 03)

22. Develop load flow equations suitable for solution by Gauss-Seidal method (JNTU May 05)

23. Mention the unspecified quantities of slack bus (JNTU Apr 03)

24. What is the information obtained from load flow studies (JNTU Jun 02)

25. Why two quantities are to be specified at each bus. (JNTU Jun 02)

26. Give a flow chart for conducting a load flow study of a power system using Gauss-Seidal method in the Y

bus frame (JNTU Jun 02)

27. If converged load flow solution is available how do you determine the slack bus complex power injection and the system total loss (JNTU Nov 02)

28. Give the classification of various buses in a load flow study (JNTU Jan 01)

29. Explain with equations, Gauss-seidal method of load flow study (JNTU Jan 01)

30. i. Explain the treatment of PV buses in load flow using Gauss-Seidal method with flow chart.ii. State and explain load flow problem (JNTU Nov 99)

31. Explain in brief the procedure for formulation of Y -Bus using singular transformation Derive the necessary equations.

32. Starting from first principles develop the equations for real and reactive bus powers. 33. Explain the G-S method for solution of non linear algebraic equations.

34. The Gauss Seidel load flow method has following disadvantages. Tick the incorrect statement.i. Unreliable coverage ii. Slow convergenceiii. Choice of slack bus effects convergence iv. A good initial guess for voltages is essential for convergence (GATE 06)

35. For the given network in Figure, obtain the bus admittance matrix (YBUS

) using the data given:

Lines between nodes Impedance p.u. Half of line charging Admittance1 – 2 0.0 + j 0.05 j 1.251 – 3 0.0 + j 0.02 j 0.502 – 3 0.0 + j 0.02 j 0.50Shunt reactor at node Impedance1 – 2 0.0 + j 2.0 (GATE 98)

36. Discuss the advantages of using Ybus

model of power system network for load-flow analysis. (IES 97)

UNIT – IV

1. Explain significance of slack bus? How voltage controlled bus is handled in N-R (polar form).(JNTU May 09)

2. Derive the expression for diagonal and off-diagonal elements of Jacobin matrix of N-R (Polar form) method. (JNTU May 09)

3. Derive necessary expressions for the off-diagonal and diagonal elements of the sub-matrices J1, J2, J3

and J4 for carrying out a load flow study on power system by using N-R method in Polar form.(JNTU May 09)

4. a. What is decoupled load flow? What are the advantages of such load flow solution?b. Distinguish between decoupled load flow solution and fast decoupled load flow solution

(JNTU May 09)

5. Perform one iteration of FDLF method for the system shower in figure 4:

Slack Bus-1: V = 1.05 +j 0.0P - V Bus -2: |V2| = 1.03 p.u. : P2 = 0.5 p.u.; 0.1 < Q2 > 0.3Load Bus -3: P3 = 0.6 p.u., Q3 = 0.25 p.u. (JNTU Nov 08)

6. Derive necessary expressions for the off-diagonal and diagonal elements of the sub-matrices J1, J2, J3

and J4 for carrying out a load flow study on power system by using N-R method in Polar form.

7. Draw the flow chart of decoupled method and explain. (JNTU Nov 08)

8. i. Describe the Newton-Raphson method for the solution of power flow equations in power systems deriving necessary equations. (JNTU Feb 07, Nov 06, Mar 06)

ii. What are P-V Buses? How are they handled in the above method.

9. i. Write a detailed note on tracking state estimation of power systems.ii. What are the difficulties encountered in state estimation and explain how these difficulties are

overcome? (JNTU Feb 07)

10. Give the general form of load flow equation to be solved in Newton- Rapshon method. Explain in detail, the approximations in Newton - Rapshon method to arrive into Decoupled methods.

(JNTU Feb 07)

11. For the system shown in figure, find the voltage at the receiving end bus at the end of first iteration. Load is 2 + j0.8 p.u. Voltage at the sending end (slack) is 1+ j0p.u. Line admittance is 1.0 – j4.0 p.u. Transformer reactance is j0.4 p.u. Use the Decoupled load flow method. Assume VR = 1Ð6 0.

(JNTU Feb 07)

12. A sample power system is shown in diagram. Determine V2 and V

3 by N.R method after one iteration.

The p.u. values of line impedances are shown in figure. (JNTU Feb 07, Nov 06)

13. Develop the equations for determining the elements of the H and L matrices in fast Decoupled method from basics. State the assumptions that are made for faster convergence.(JNTU Feb 07, Nov 04)

14. For the network shown in fig, obtain the complex bus bar voltages at bus (2) at the end of first iteration, using Fast Decoupled method. Line impedances are in p.u. Given Bus (1) is slack bus with. V

1 = 1.0Ð00,

P2 + jQ

2 = 5.96 + j1.46

|V3| = 1.02 P

3 = 2.0 p.u.

Assume V2

0 = 1Ð00 and V30 = 1.02Ð00. (JNTU Nov 06, 04)

15. For the system shown in figure3, find the voltage at the receiving end bus at the end of first iteration. Load is 2 + j0.8 p.u. Voltage at the sending end (slack) is 1+ j0p.u. Line admittance is 1.0 - j4.0 p.u. Transformer reactance is j0.4 p.u. Use the Decoupled load flow method. Assume VR = 1Ð00.

(JNTU Nov 06)

16. Consider the three bus system. The p.u line reactances are indicated on the figure. The line resistances are negligible. (JNTU Nov 06)

The data of bus voltages and powers are given below

Bus No Type Latest Voltages Generation DemandP Q P Q

1 Slack 1 ∟00 - - - -

2 PQ 1.01 ∟-80 0.6 0.4 0.5 0.33 PQ 0.97 ∟-100 - - 0.7 0.2

Determine the load flow solution to be solved using Decoupled method for one iteration.

17. i. Derive fast - Decoupled power flow analysis algorithm and give steps for implementation of this algorithm.

ii. State merits and demerits of this method. (JNTU Nov 06, 05, 02)

18. i. Obtain the Decoupled load flow model starting from Newton Raphson method. (JNTU Mar 06)ii. What are the assumptions made in fast decoupled method to speed up the rate of convergence ?

19. Using data given below, obtain V3 using N.R..method after first iteration as shown in the figure.

Bus code p-q Impedance zpq1-2 0.08 + j0.24 p.u1-3 0.02 + j0.062-3 0.06 + j0.18

Generation LoadBus code Assumed bus Megawatts Megavars Megawatts Megawars

1 1.05 + j0 p.u 0 0 0 02 1.0 + j0 20 0 50 203 1.0 + j0 0 0 60 25 (JNTU Mar 06)

20. Formulate the Newton-Raphson method for the solution of power flow equations deriving necessary

(JNTU Mar 06)

21. Carry out one iteration of load flow solution for the system shown by Fast-Decoupled methodas shown in the figure3. Take Q limits of generator 2 as Qmin = 0, Qmax = 5Bus 1 slack bus Vspecified = 1.05 00.Bus 2 PV bus | V |specified = 1.00 p.u. , PG = 3 p.u.Bus 3 PQ bus PD = 4 p.u., QD = 2 p.u. (JNTU Nov 05)

22. Find 2 and Q2 for the system shown in figure4 use. N. R. method upto one iteration.(JNTU Nov 05)

23. Develop the power flow model using Decoupled method and explain the assumptions made to arrive at the Fast Decoupled load flow method. Draw the flow chart and explain. (JNTU Nov 04)

24. i. Derive the Power flow equations and therefore explain Newton Raphson method of load flow solution.ii. Explain the terms ‘P-Q, ‘P-V’, and slack buses for a Power system and indicate their significance.

(JNTU May 04)

25. i. Deduce necessary relations to evaluate bus voltages and line flows using Newton Raphson method. Explain the computer algorithm.

ii. Explain how the voltage controlled buses are dealt with. (JNTU Nov 04)

26. i. Discuss the algorithm for the Newton Raphson method for load flow solution with P.V. buses also included in the power system.

ii. Derive the necessary expressions for Jacobian matrix elements for N-R method in Polar form.(JNTU Nov 03)

27. The figure below shows a three bus power system. Line impedances are given in p.uBus 1 PQ P

D = 60; Q

D = 25

Bus 2 PV PG = 20; P

D = 50; Q

D = 20

Bus 3 Slack

Carry out one iteration of load flow solution by Fast-Decoupled load flow method.(JNTU Nov 04)

28. i. Derive the Power balance equations in a power system and there from explain the N R method of load flow analysis. Draw the flow chart giving the sequence of analysis. Show that the Polar Coordinate representation is advantages over the rectangular coordinates.

ii. Explain the advantages of using Bus Admittance matrix in load flow studies. (JNTU Mar 04)

29. Among the various methods of solving power system equation discuss the various factors upon which a particular method is selected for our approach. (JNTU Nov 04)

30. The sample system with the per unit impedance of lines based on 100MVA base is shown in figure. The load on bus 3 is 2.0 + j1.0, and its voltage magnitude is to be held constant at 1.0 per unit by means of the synchronous condenser at bus 2. The maximum and minimum limits of the reactive

power to be supplied by the condenser are 0.5 and –0.1 respectively. With bus 1 as slack having voltage of 1.05"0op.u. make a load - flow study using Fast – Decoupled method.(JNTU Nov 04)

31. Draw and explain the flow chart for N-R method of load flow solution in rectangular form with necessary Equations. (JNTU Nov 04)

32. Consider the single line diagram of a Power system shown in fig. Take bus 1 as slack bus and the YBUS matrix is given below: (JNTU Nov 04)

YBUS

=

Scheduled generation and loads are as follows:

Bus No.Generation Load Assumed Bus

VoltagesMW MVAR MW MVAR1 0 0 0 0 1.04+j0.02 0 0 250 150 1.0+j0.03 100 70 50 20 1.0+j0.0

Using Newton-Raphson method, obtain the bus voltages at the end of 1st iteration.

33. i. Explain briefly what you understand by load flow solution. Obtain the mathematical model for the above study using Newton Raphson method. Use polar coordinate method.

ii. Draw a flow chart for the above method and explain the major steps involved. (JNTU Nov 03)

34. Explain clearly with a detailed flow chart the computational procedure for load flow solution using decoupled method deriving necessary equations. (JNTU Nov 03)

35. Obtain the necessary equations for the load flow solution using N-R method. What is Jacobian matrix? Derive the necessary equations for computing all the elements of the above matrix using rectangular coordinates. (δ & w). (JNTU Nov 03)

36. Give a neat flow chart for N-R method of solving load flow equations using rectangular coordinates. Explain clearly the major steps involved in the solution (i) what P.V. suses are not present and (ii) when P. V. buses are present. (JNTU Nov 03)

37. Explain with a flow chart and necessary equations how Newton Raphson method is applied to conduct load flow studies for a power system having voltage controlled buses and load buses. Use rectangular

coordinates. Derive the expressions for the elements of Jacobian matrix in the above method.(JNTU Nov 03)

38. Compare the performance of decoupled and fast- Decoupled method for load flow solution using nodal admittance approach for the formulation of load flow equations. (JNTU May 03)

39. Explain with a flow chart, the computational procedure for load flow solution using fast decoupled method. (JNTU May 03)

40. Comment on the following statements.i. Computational procedure in load flow equations solution depends upon type of bus.ii. The power flow equations will never permit us to solve for the individual phase angles 1 and 2, but

only these differences, δ0- δ

2.

iii. All the generation variables cannot be specified a priori. (JNTU May 03)

41. Write about notes on the following. (JNTU May 03)i. Data for power flow studies.ii. Merits and demerits of using polar and rectangular coordinates in load flow studies.

42. i. Define and explain the power flow problem. (JNTU Nov 02)ii. Explain the necessity of load flow studies in power systems.

43. A 250 MVA, 11 KV, 3 phase generator is connected to a large system through a transformer and a line as shown in figure below.

Equivalent SystemThe parameter, on 250 MVA base, are as follows:Generator : X

1 = X

2 = 0.15 p.u., X

0 = 0.1 p.u.

Transformer : 11/200 kV, 250 MVA X

1 = X

2 = X

0 = 0.12 p.u.

Line : X1 = X

2 = 0.25 p.u., X

0 = 0.75 p.u.

Equivalent system : X1 = X

2 = X

0 = 0.15 p.u.

i. Draw the sequence network diagram for the system and indicate the p.u. reactance values.ii. Find the driving point impedance of node 2.iii. Find the fault MVA for a single line to ground fault at node 2. Assume the pre fault voltages at all the

nodes to be 1.0 p.u. (JNTU Nov 02)

44. i. Explain clearly with a flow chart the computational procedure for a load flow solution using Fast Decoupled load flow method. (JNTU Nov 02)

ii. Explain how the decoupling and logical simplification of FDLF algorithm is achieved?

45. i. Compare GS and NR methods with reference to load flow problem bringing out their advantages and disadvantages.

ii. Classify various types of buses in a power system for load flow studies. Justify the classification.(JNTU Nov 02)

46. i. Explain clearly with a flow chart the computational procedure for a load flow solution using Decompled Newton method.

ii. Mention the advantages of the DLF as compared to NR method. (JNTU Nov 02)

47. i. Explain about the data required for power flow studies. (JNTU Nov 02)ii. Describe the Newton-Raphson method for the solutions of power flow equations in power systems.

48. i. Briefly compare Newton Raphson method and Fast Decoupled method of solving power flow problem.ii. Justify the assumptions made in Newton Raphson method to arrive at Decoupled method.

(JNTU Nov 02)

49. The bus admittance matrix of a sample Power system is (1) (2) (3)

YBus

(1) [ -5 = j30 1-j10 4-j20 ](2) [ 1 - j10 -5 = j30 1-j10 ](3) [ 4 - j20 1-j104 -5 + j308]

Bus data areBus No. Type P

GQ

GP

LQ

L

1. P - V 2.9034 - - -2. P - Q - - 4.0089 1.79153. Slack - - - -the latest solution isV

1 = 1.05 ∟4.6960

V2 = 0.9338 ∟-8.80

V3 = 1.0 ∟00

Determine the load flow equation to be solved for voltage correction using Decoupled method.

50. Consider the three bus power system shown in Fig. The PU reactances are indicated with resistance neglected. The magnitude of the three bus voltages are specified to be 1.0 pu. The bus powers are specified in the following table:-

Bus Real Demand Reactive Demand Real Generation Reactive Generation1 P

D1=1.0 Q

D1=0.6 P

G1=? Q

G1=unspecified

2 PD2

=0.0 QD2

=1.0 PG2

=1.4 QG2

=unspecified3 P

D3=1.0 Q

D3=1.0 P

G3=0.0 Q

G3=unspecified

Carry out the decoupled load flow solution. (JNTU Mar 00)

51. i. Classify various types of buses and briefly explain the method of handling in load flow studiesii. Develop load flow equations suitable for solution using NR method using polar coordinates. Draw the

flow chart (JNTU Mar 99)

52. Carry out one iteration of load flow solution for the system shown by Fast – Decoupled method. Take Q limits of generator 2 as Q

min = 0, Q

max=5

Bus 1 Slack bus Vspecified

= 1.05?0?.Bus 2 PV bus |V|

specified = 1.00 p.u., P

G = 3 p.u.

Bus 3 PQ bus PD = 4 p.u., Q

D = 2 p.u. (GATE 03)

53. For the network shown in figure with bus 1 as the slack bus use the following methods to obtain one iteration for the load flow solution (GATE 00)

i. Newton Raphson using YBus

.ii. Fast decoupled method.

Line No Between buses Line Impedance Half line charging Admittance

1. 1-2 0 + j0.1 02. 2-3 0 + j0.2 03. 1-3 0 + j0.2 0

BUS DATA

BUS Type Generator Load Voltage ReactiveMagnitude Power Limit

NO P Q P Q Qmin

Qmax

1 Slack - - - - 1.0 - -2. PV 5.3217 - - - 1.1 0 5.32173. PQ - - 3.6392 0.5339 - - -

54. Find analytical solution to load flow problem for a two bus system having one slack and one load bus (GATE 99)

55. The single line diagram of a network is shown in figure below. The line series reactance is 0.001 p.u. per km and shunt susceptance is 0.0016 pu per km. Assemble the bus admittance matrix (Y

Bus) of the

network, neglecting the line resistance. (GATE 94)

56. The elements of each row of a YBUS matrix for load flow studies in power system and upto zero.i. alwaysii. if the shunt admittances at the buses are ignorediii. if mutual couplings between transmission lines are absentiv. if both (ii) and (iii) are satisfied (IES 06)

57. Write load flow equations for a three bus system having one slack, one generator, and a load bus in rectangular form (IES 02)

58. What are the reasons for diverging load flow solutions? (IES 00)

59. Develop necessary equations and describe the load flow solution using gauss seidel method. (IES 99)

60. A single-phase load of 100 KVA is connected across lines bc of a 3-phase supply of 3.3 kv. Determine symmetrical components of line currents. (IES 98)

61. For the Ybus matrix given in pu values. Draw the reactance diagram Ybus = J -6 2 2.5 0 1 bus 2 -10 2.5 4 2 bus 2.5 2.5 -9 4 3 bus 0 4 4 -8 4 bus

If the line (2)-(4) is deleted due to line outage, give the modified Ybus

62. Derive equations for elements of Jacobian using i. Rectangular coordinatesii. Polar coordinates

UNIT – V

1. a. Prove that Zpu(new) = Zpu(old) × (JNTU May 09, Nov 08)

b. Obtain pu impedance diagram of the power system of figure 5. Choose base quantities as 15 MVA and 33 KV.Generator: 30 MVA, 10.5 KV, X′′ = 1.6 ohms.Transformers T1 & T2: 15 MVA, 33/11 KV, X = 15 ohms referred to HVTransmission line: 20 ohms / phaseLoad: 40 MW, 6.6 KV, 0.85 lagging p.f.

2. For the system shown in figure 5. Find short circuit capacity at bus 3.

3. a. What are the advantages of p.u system.b. For the network shown in figure 5b draw p.u impedance diagram. (JNTU May 09, Nov 08)

4. Draw the pu impedance diagram for the system shown in figure 5. Choose Base MVA as 100 MVA and Base KV as 20 KV. (JNTU Nov 08)

5. a. Prove that Base impedance =

b. Obtain pu impedance diagram of the power system of figure 5b. Choose base quantities in generator circuit.Generator: 20 MVA, 11 KV, X”= 0.1 puTransformer: 25 MVA, 11/33 KV, X = 0.1 puLoad: 10 MVA, 33 KV, 0.8 pf lag. (JNTU Nov 08)

6. i. Derive the expressions for bus voltages, line currents when a three phase symmetrical fault through a fault impedance occurs at a particular bus, using bus impedance matrix.

ii. A three phase fault with a fault impedance of 0.16 p.u. occurs at bus 3, for which ZBUS

is give by:

Compute the fault current, the bus Voltages, and the line currents during the fault. Assume prefault bus voltages 1.0 per unit. (JNTU Feb 07, Mar 06)

7. i. Develop the performance equations in impedance form using 3-Φ representation for finding fault voltages and fault currents when a fault occurs at a bus.

ii. The per unit ZBUS matrix for a power systems is given by 1 2 3

ZBUS

=

A three phase fault occurs at bus 3 through a fault impedance of j 0.19 p.u. ohms. Calculate the fault current, bus voltages and line currently during the fault. (JNTU Mar 06)

8. Derive the expressions for fault current voltages at the bus ‘p’ where the fault current, voltages at the other buses during fault. Current through the elements when a three-phase to-ground fault occurs at bus ‘p’, using fault impedance Bus Impedance matrices in phase Component form. (JNTU Mar 06)

9. Write the procedure to be followed to calculate the voltage and current during symmetrical fault using Thevenin’s Theorem. (JNTU Nov 05)

10. For a three phase symmetrical fault on a balanced power system using matrix notation derive the expression for. (JNTU Nov 04)

i. Current in the faulted busii. Current at any other busiii. Voltage at any bus excluding the faulted bus

11. Write the three phase representation of power system for short circuit studies and briefly explain.(JNTU Nov 04)

12. Discuss the effect of a star-delta transformer on the above fault current with fault occurring on either side of this transformer. (JNTU Nov 04)

13. i. A generating station A has a short circuit capacity of 1000 MVA. Another station B has a short circuit capacity of 650 MVA. They are operating at 11KV. Find the short circuit MVA. If they are interconnected by a cable of 0.5 ohm reactance per phase.

ii. In what respect the fault calculations for an alternator terminals are different from the fault calculations for a fault in a power system network. (JNTU Nov 04)

14. i. Discuss the behavior of a 3 synchronous generator subjected to symmetrical three phase short circuit. Hence define the several reactances of the synchronous machine and their time constants.

ii. Explain how is the knowledge of these reactances and their time constants are useful?(JNTU Nov 03)

15. A synchronous generator is rated 100 MVA, 11KV, Xd = 0.2 p.u. The generator is connected to a step-

up transformer with ratings of 150 MVA, 12 KV(delta)/132 KV (star), X = 0.09 p.u. Compute fault current in amps for three-phase fault at H.T. terminals of the tranformer. (JNTU May 03)

16. i. Sketch the waveform of a stator current of a synchronous generator when subjected to a 3-phase short circuit at its terminals and explain the salient features of this waveform.

ii. Three 6.6 KV alternators of rating 2 MVA, 5 MVA and 8 MVA having per unit reactances of 0.08, 0.12 and 0.16 respectively are connected to a common bus. From the bus, a feeder cable of reactance of 0.125 ohm connects to a sub-station. Calculate the fault MVA, if a 3-phase symmetrical fault occurs at the sub-station. (JNTU May 03)

16. i. Discuss the effect of fault impedance on the fault current.

ii. A 3-phase, 25 MVA, 11KV, alternator with X0 = 0.05 p.u, X1 = X

2 = 0.15 p.u is earthed through a

reactance of 0.333 ohms. Calculate the fault current for a single line to ground fault. Derive the formulate employed. (JNTU May 04)

17. i. Derive an expression to calculate the fault current phase and line voltages in a network of an unloaded generator for line to ground fault on phase “A”. (JNTU Nov 02)

ii. Draw the connection of sequence networks for single line to ground fault through impedance “Zf”18. i For a three phase symmetrical fault on a balanced power system using matrix notation derive the

expression for (i) Current expression for (ii) Current at any other bus (iii) Voltage at any bus excluding the faulted bus.

ii. Write the three phase representation of power system for short circuit studies and briefly explain.(JNTU Nov 02)

19. Write short note on the assumptions made in short circuit studies. (JNTU Nov 02)

20. The p.u parameters for a 500 MVA machine on its own base are:inertia, M=20 p.u ; reactance, X=2 p.uThe p.u values of inertia and reactance on 100 MVA common base, respectively, arei) 4, 0.4 ii) 100, 10 iii) 4, 10 iv) 100, 0.4 (GATE 05)

21. A 75 MVA , 10 kV synchronous generator has Xd = 0.4 p.u. The Xd value (in p.u) to a base of 100

Mva, 11kV isi) 0.578 ii) 0.279 iii) 0.412 iv) 0.44 (GATE 01)

22. In the power system circuit diagram shown in figure the current limiting reactor X is to be chosen such that the feeder breaker rating does not exceed 425 MVA. The system data is as follows:Feeder transformer reactance : 10% on 50 MVA base.The generating source A, B, C have individual fault levels of 1000 MVA with respective generator breakers open. Ignore pre fault currents and assume 1.0 P.U. voltages throughout before fault. Assume common base of 1000 MVA. (GATE 96)

23. A single line diagram of a power network is shown in figure

The system data is given in the table below:

Element Positive Sequence Negative Sequence Zero SequenceGenerator G 0.10 0.12 0.050

Motor M1 0.05 0.06 0.025Motor M2 0.05 0.06 0.025Transformer T1 0.07 0.07 0.070Transformer T2 0.08 0.08 0.080Line 0.10 0.10 0.100Generator ground reactance is 0.5 P.U.

i. Draw sequence networksii. Find fault currents for a line to line fault on phases B and C at point q. Assume 1.0 P.U. per fault

voltage throughout. (GATE 96)

UNIT – VI

1. A balanced 200 V, 3 phase supply feeds balanced resistive load as shown in figure. If the resistance Rbc is disconnected. Determine Ia, Ib and Ic and symmetrical components of Ia, Ib and Ic.

(JNTU May 09)

2. A 400 V balanced 3 phase supply is connected to a delta connected resistive load as shown in figure 6. Determine symmetrical components of Ia, Ib, Ic. (JNTU May 09)

3. A generator having a solidly grounded neutral and rated 50 MVA, 30 KV has positive, negative and zero sequence reactances of 0.25, 0.15 and 0.05 pu respectively. What reactance must be placed in the generator neutral to limit the fault current of a LG fault to that for a 3 phase fault. (JNTU May 09)

4. a. Pabc is 3 phase power in a circuit and P012 is power in the same circuit in terms of symmetrical components. Show that Pabc = P012.

b. The line currents in a 3 phase supply to an un balanced load are respectively Ia = 10 + j20; Ib = 12 - j10; Ic = -3 - j5 Amp. phase sequence is abc. Determine the sequence components of currents.

(JNTU May 09)

5. For the system shown in figure 6. A a LL fault occurs at point F. Find fault current.

(JNTU Nov 08)

6. Develop the expressions for the following matrices which are used for shunt fault analysis for a Line-to-Line fault occurring on conventional phases.

i. Fault admittance matrix in phase and sequence component form.ii. Derive the formulae used. (JNTU Nov 06)

7. Develop the necessary matrices ofi. Fault admittance matrix is phase and sequence component form. ii. Fault impedance matrix in sequence component form for a three phase fault at a bus in a power system,

for short circuit studies. (JNTU Nov 06)

8. Derive the expressions for fault Current at the buses and lines, Voltages at the faulted bus and at other buses when a single? Line-to-ground fault occurs at a bus on conventional phase ‘a’, using fault impedance and Bus impedance matrices, in sequence component form. (JNTU Nov 06)

9. Develop the necessary matrices ofi. Fault admittance matrix in phase and sequence component form.ii. Fault impedance matrix in sequence component form for a three phase fault at a bus in a power system,

for short circuit studies. (JNTU Mar 06)

10. Develop the expressions for fault admittance matrix in phase Component form for a double-line-to-ground fault occurring on conventional phases. (JNTU Mar 06)

11. A 25 MVA 11Kv three phase synchronous generator has a sub transient reactance of 20%. The generator supplies two motors over a transmission line with transformers at both ends of the line as shown in the one Line diagram of figure2. The motors each rated 7.5 MVA and 15 MVA at 10Kv. Each motor has Sub transient reactance of 20% based on its rating. The three phase transformers each rated 30 Mva 8/121 Kv are delta-star connected have a leakage reactance of 10%. The transmission line has a reactance of 100 ohms. Assume negative sequence reactance of the motor to be same as sub transient reactance. Assume zero sequence reactance of generator as 0.06 p.u. A current limiting reactor of 2.5 ohm each are connected in the neutral of generator and motor number 2. The zero sequence reactance of transmission line is 300 ohms. The system is on no load at the rated voltage. Draw the positive, negative and zero sequence network choosing generator rating as the base.

(JNTU Mar 06)

12. Give a step by step procedure of analyzing a L-G fault on a power system by bus impedance matrix method and explain. (JNTU Nov 04)

13. i. Draw and explain how zero sequence networks are represented for 3 phase transformers with different winding connections.

ii. Briefly explain the representation of a three phase star connected neutral grounded synchronous generator in the positive, negative and zero sequence networks. (JNTU Nov 04)

14. Derive the expression for the fault current for a line to line and ground fault (LLG). Draw the sequence network connection also. (JNTU Nov 04)

15. Three 6.6 KV, 3 phase, 10 MVA alternators are connected to a common bus. Each alternator has a positive sequence reactance of 0.15 p.u. The negative and zero sequence reactances are 75% and 30% of positive sequence reactance. A single line to ground fault occurs on the bus. Find the fault current if

i. All the alternator neutrals are solidly grounded. ii. One alternator neutral is solidly grounded and the other two neutrals are isolated. iii. One alternator neutral is grounded through 0.3 ohm resistance and the other two neutrals are isolated.

(JNTU Nov 04)

16. i. A generator with grounded neutral has sequence impedances of Z1, Z

2 and Z

0 and generated emf E. If a

single line to ground fault occurs on terminals of phase “A”, Find Vb, V

c. Assume Z

f = 0.

ii. Write short notes on zero sequence networks for two winding transformers. (JNTU Nov 04)

17. i. Show that positive and negative sequence currents are equal in magnitude but out of phase by 180o in a line to line fault. Draw a diagram showing interconnection of sequence networks for this type of fault.

ii. A 3 phase 37.5 MVA, 33 KV alternator having X1 = 0.18p.u., X

2 = 0.12p.u., and X

0 = 0.1p.u., based on

its rating is connected to a 33 KV overhead line having X1 = 6.3 ohms, X

2 = 6.3 ohms and X

0 = 12.6

ohms per phase. A line to ground fault occurs at the remote end of the line. The alternator neutral is solidly grounded. Calculate fault current. (JNTU Nov 04)

18. The figure represents a sample power system.

Each generator is rated 100 MVA, XI = X

2 = 15%, X

0 = 5%

Each transformer is rated 150 MVA, X1 = X

2 = X

0 = 8%. Transmission line has X

1 = X

2 = 15% and X

0

= 4% on 100 MVA base. Calculate fault currents in the line if there is L - G fault at bus(2).(JNTU May 03)

19. i. Discuss the effect of fault impedance on the fault current. (JNTU Nov 02)ii. A 3-phase, 25 MVA, 11 KV, alternator with X

0=0.05 p.u, X

1=X

2=0.15 p.u is earthed through a

reactance of 0.333 ohms. Calculate the fault current for a single line to ground fault. Derive the formulae employed.

20. i. A 25 MVA: 13.2 KV alternator with solidly grounded neutral has a sub transient reactance of 0.25 p.u. The negative and zero sequence reactance are 0.35 p.u and 0.1 p.u respectively. A single line to ground fault occurs at the terminals of unloaded alternator. Determine the fault current.

ii. Explain the equal area criterion, how this is useful in obtaining stability limit. (JNTU Nov 02)

21. Write short note on the symmetrical components. (JNTU Nov 99)

22. Three identical star connected resistors of 1.0 pu are connected to an unbalanced 3 phase supply. The load neutral is isolated. The symmetrical components of the line voltages in pu are: Vab

1 = X∟θ

1,

Vab2 = X∟θ

2. If all calculations are with the respective base values, the phase to neutral sequence

voltages are

i.

ii.

iii.

iv. (GATE 06)

23. i. Develop the inter connection of sequence networks for a line to line fault. Derive the necessary expressions.

ii. For the figure shown below compute the fault current for a LG fault at P. (GATE 01)

24. A synchronous generator is connected to an infinite bus through a lossless double circuit transmission line. The generator is delivering 1.0 p.u power at a load angle of 300 when a sudden fault reduces the peak power that can be transmitted to 0.5 p.u. After clearance of fault, the peak power that can be transmitted becomes 1.5 p.u. find the critical clearing angle. (GATE 01)

25. A three phase star connected alternator is rated 30 MVA, 13.8 kV and has the following sequence reactance values:X

1 = 0.25 p.u.; X

2 = 0.35 p.u. and X

0 = 0.10 p.u.

The neutral of the alternator is solidly grounded. Determine the alternator line currents when a double line to ground fault occurs on its terminals. Assume that the alternator is unloaded and is operating at rated voltage when the fault occurs. (GATE 95)

26. A single line diagram of a power system is shown in figure, where the sequence reactances of generator (G), synchronous motor (M) and transformers (T1, T2) are given in per unit. The neutral of the generator and transformers are solidly grounded. The motor neutral is grounded through a reactance X

n = 0.05 per unit. Draw the positive, negative and zero sequence networks with reactance

values in per unit on a 100 MVA, 13.8 kV base in the zone of the generator. The prefault voltage is 1.05?20 per unit. Calculate the per unit fault current for a three phase to ground fault at bus ’d’. The system data are as follows:G – 100 MVA; 13.8 kV; X

1 = 0.15; X

2 = 0.17; X

0 = 0.05

T1, T

2 – 120 MVA; 13.8kV/138kV?/Y; X = 0.12

M – 100 MVA; 13.8 kV; X1 = 0.2, X

2 = 0.21, X

2 = 0.21, X

0 = 0.1; X

n = 0.05

Line X – X1 = X

2 = 20 Ohms; X

0 = 60 Ohms (GATE 92)

27. A 3 Phase, star connected generator supplies a star connected inductive load through a transmission line. The star point of the load is grounded and the generator neutral is ungrounded. The load reactance is j 0.5 pu per phase and the line reactance is j 0.1 pu per phase. The positive, negative and zero sequence reactances of the generator are j 0.5, j 0.5 and j 0.05 pu respectively. (GATE 92)

28. For the system shown in the diagram given above, what is a line to ground fault on the line side of the transformer equivalent to ?

i. A line-to-ground fault on the generator side of the transformerii. A line to line fault on the generator side of the transformeriii. A double line to ground fault on the generator side of the transformeriv. A 3-phase fault on the generator side of the transformer (IES 06)

29. A three phase are connected synchronous generator with a grounded neutral is operating on no load at rated voltage. With the usual notation develop the necessary algorithm for computing fault current and voltages of the healthy phases following.

i. A single line to ground faultii. Line-line fault at the machine terminals. (IES 98)

UNIT – VII

1. A 275 KV transmission line has following line constants. (JNTU May 09)A = 0.85 50, B = 200 750

The line delivers 150 MW with |VS| = |VR| = 275KV . Determine synchronizing power coefficient.

2. A 3 phase 50 Hz transmission line is 200 Km long. The line parameters are r = 0.1 ohm /Km; x = 0.25 ohm/km; y = 3 × 10-6 mho / Km. The line is represented by nominal π model. If |VS| = |VR| = 200KV determine steady state stability limit. (JNTU May 09)

3. A salient pole synchronous generator is connected to an infinite bus via a line. Derive an expression for electrical power output of the generator and draw p-δ curve. (JNTU Nov 08)

4. A generator supplies 1.0 pu power to an infinite bus as shown in figure 7. The terminal voltage and infinite bus voltage are 1.0 pu. All the reactances are on a common base. Determine steady state stability limit:

a. when both lines are in b. when one line is switched off (JNTU Nov 08)

5. a. Define steady state stability.b. Two turbo alternators with ratings given below are connected via a short line.

Machine 1: 4 pole, 50 Hz, 60 MW, 0.8 pf lag.Moment of inertia 30, 000 kg-m2

Machine 2: 2 pole, 50 Hz, 80 MW, 0.85 pf lag.Moment of inertia 10,000 kg-m2.Calculate the inertia constant of single equivalent machine on a base of 200 MVA.(JNTU Nov 08)

6. a. Define steady state stability limit.b. Derive steady state stability limit of a line with generalised circuit constants of A, B, C and D if

sending end and receiving end voltages are VS and VR. (JNTU Nov 08)

7. A 3 phase 50 Hz transmission line is 200 Km long. The line parameters are r = 0.1 ohm /Km; x = 0.25 ohm/km; y = 3 × 10-6 mho / Km. The line is represented by nominal π model. I f |VS| = |VR| = 200KV determine steady state stability limit.

8. i. Define the following terms : (JNTU Feb 07, Nov 06, May 04)a. Steady state stability limitb. Dynamic state stability limitc. Transient state stability limit

ii. List the assumptions made in the transient stability solution techniques.iii. Derive the expression for steady state stability limit using ABCD parameters.

9. i. Discuss the methods to improve steady state and transient state stability margins.ii. What is equal area criterion? Explain how it can be used to study stability? Select any suitable

example. (JNTU Feb 07, Nov 02)

10. i. What is power system stability? Define stability limit of the system.ii. Why transient state stability limit is less than steady state stability limit? Explain?iii. Draw diagrams to illustrate the application of equal area criterion to study transient stability when a

fault on one of the parallel lines of a two circuit line feeding an Infinite bus. The fault is very close to the sending end bus and is subsequently cleared by the opening of faulted line. Mark the accelerating and decelerating areas in the diagram. (JNTU Nov 05)

11. i. Distinguish between steady state, transient state and dynamic stability.ii. Derive the power angle equation of a single machine connected to infinite bus.iii. Explain the following terms (i) transfer reactance (ii) Inertia constant. (JNTU Nov 04)

12. i. Give details of assumptions made in the study of steady state and transient stability solution techniques.

ii. Give important difference between steady state, dynamic state and transient state stability studies.iii. Give the list of methods to improve transient state stability limits. (JNTU May 04)

13. i Derive a swing equation of a single machine connected to infinite bus.ii. Explain the following terms: (i) Transfer reactance (ii) Inertia constant.iii. Draw a diagram to illustrate the application of equal area criteria to study transient stability when there

is a sudden increase in the input of generator. (JNTU Nov 03)

14. i. Write a short notes on methods of improving stability of power system.ii. A generator operating at 50 Hz delivers 1 p.u power to an infinite bus through a transmission circuit in

which resistance is neglected. A fault takes place reducing the maximum power tranferable to 0.3 p. where as before the fault this power was 2.0 p.u. and after the clearance of the fault it is 1.5 p.u.. By the use of equal area criterion determine the critical clearing angle. (JNTU Nov 03)

15. Derive the swing equation from first principle. (JNTU May 03)

16. i. What do you understand by stability limit, steady state stability limit, Transient stability limit.ii. Distinguish between steady state stability and Dynamic stability.iii. What do you understand by critical cleaning time and Critical cleaning angle. Derive the expression for

critical cleaning angle for a synchronous machine connected to infinite bus system when a 3 phase fault occurs and it is cleared by opening of circuit breakers. (JNTU Nov 02)

17. Clearly explain what you understand by stability. Distinguish between steady state and Transient stability. (JNTU Nov 02)

18. i. Derive the power angle equation of a single machine connected to infinite bus.ii. Explain the following terms (i) transfer reactance (ii) Inertia constant.

19. Derive the expression for steady state stability limit using ABCD parameters. (GATE 02)

20. A generator is delivering rated power of 1.0 per unit to an infinite bus through a lossless network. A three phase fault under this condition reduces P

max 100 per unit. The value of P

max before fault is 2.0

per unit and 1.5 per unit after fault clearing. If the fault is cleared in 0.05 seconds, calculate rotor angles at intervals of 0.05 sec from t = 0 sec to 01 secs. Assume H = 7.5 HJ/MVA and frequency to be Hz. (GATE 92)

21. The steady state stability limits for round rotor and salient pole 3-phase synchronous generator are attained at the values of power angle

i. = /2, and = /2, respectively ii. < /2, and < /2, respectivelyiii. < /2, and = /2, respectively iv. = /2, and < /2, respectively (IES 06)

22. The inertia constant of a machine is 2.5 magajoules/Mva at the rated speed. The system frequency is 50Hz. What is the inertia constant M expressed in pu-sec2/electrical degree (OU Apr 03)

23. Write the factors affecting steady state stability limit. (OU May 05)

UNIT – VIII

1. a. What are the assumptions made in deriving swing equation.b. Explain point by point method of determine swing curve. (JNTU May 09)

2. a. Explain point by point method of solving swing equation.b. Explain methods of improving transient stability. (JNTU May 09)

3. A 50 Hz, 500 MVA, 400 KV generator (including transformer) is connected to a 400 KV infinite bus bar through on inter connector. The generator has H = 2.5 MJ/MVA. Voltage behind transient reactance 420 KV and supplies 460 MW. The transfer reactance between generator and bus bar under various conditions are Prefault = 0.5 pu; During fault = 1.0 pu; Post fault = 0.75 pu. Calculate swing curve using ∆T = 0.05 sec, with fault cleared at 0.1 secs. The period of study is 0.2 secs. (JNTU May 09)

4. a. Explain the methods of improving transient stability.b. A single machine supplies power to an infinite bus over a double circuit line. Discuss transient

stability of the system when one of the circuit is suddenly switched off. (JNTU May 09)

5. A synchronous generator represented by a voltage source of 1.0 pu in series with a transient reactance of j 0.15 pu and inertia constant of 2.5 MJ/MVA is connected to an infinite bus through a line of reactance of j 0.3 pu. The infinite bus is represented by a voltage source of 1.0 pu in series with a reactance of j 0.2 pu. The generator is supplying an active power of 1.0 pu when a 3 phase fault occurs at its terminals. If the fault is cleared in 100 milli seconds. Determine system stability by plotting swing curve. Take ∆t = 0.05 secs. (JNTU Nov 08)

6. a. Explain point by point method of solving swing equation.

b. Explain methods of improving transient stability. (JNTU Nov 08)

7. a. What are the assumptions made in deriving swing equation.b. Explain point by point method of determine swing curve. (JNTU Nov 08)

8. For the system shown in figure 8, a 3 phase fault occurs at the middle of one of the transmission lines and is cleared by simultaneous opeining of circuit breakers at both ends. If initial power of generator is 0.8 pu, determine the critical clearing angle. (JNTU Nov 08)

9. i. What are the factors that affect transient stability?ii. What are the methods used to improve the transient stability limit?iii. Write some of the recent methods for maintaining stability? (JNTU Feb 07, Nov 06, Mar 06)

10. i. A generator operating at 50Hz delivers 1 p.u. power to an infinite bus through a transmission circuit in which resistance is neglected. A fault takes place reducing the maximum power transferable to 0.3 p.u. where as before the fault this power was 2.0 p.u. and after the clearance of the fault it is 1.5 p.u.. By the use of equal area criterion determine the critical clearing angle.

ii. Derive the formula used in the above problem. (JNTU Feb 07, Nov 06, 05)11. i. Derive and explain the concept of equal area criterion for stability analysis of a power system.

ii. Discuss why i. Transient stability limit is lower than steady state stability limit ii.the use of automatic reclosing circuit breakers improves system stability

(JNTU Feb 07, Nov 06, May 04, 03)

12. i. Discuss the general considerations and assumptions that are taken into account while studying transient stability. (JNTU Feb 07, Nov 05)

ii. Discuss the various techniques adopted to improve transient stability limit.

13. Draw the diagrams to illustrate the application of equal area criterion to study transient stability for the following cases :

i. A switching operation causing the switching out of one of the circuits, of a double circuit line feeding an infinite bus.

ii. A fault on one of the parallel circuits of a two circuit line feeding an infinite bus. The fault is very close to the sending end bus and is subsequently cleared by the opening of faulted line.(JNTU Nov 06)

14. Write a short notes on methods of improving stability of power system. (JNTU Nov 06, 05)

15. i. What are the methods of improving transient stability.ii. A generator is delivering 1.0 p.u. power to infinite bus system through a purely reactive network. A

fault occurs on the system and reduces the output to zero. The maximum power that could be delivered

is 2.5 p.u.. When the fault is cleared, original network conditions exist again. Compute critical clearing angle. (JNTU Nov 06)

16. i. Discuss the various factors that affects the transient stability of a power system. (JNTU Mar 06)ii. Discuss how equal area criterion can be employed for determining critical clearing angle.

17. i. What are the factors that affect transient stability?ii. What are the methods used to improve the transient stability limit ?iii. Write some of the recent methods for maintaining stability? (JNTU Mar 06)

18. i. What is swing curve? Explain its significance and applications.ii. What is equal are criterion? Explain its significance and applications.iii. Discuss the limitations of equal area criterion of methods of stability study. (JNTU Nov 04)

19. What is equal area criterion of Transient stability? How is it used to estimate the stability of a machine when a fault on the system connected to it is cleared after a few cycles by the circuit breakers.

(JNTU Nov 04)

20. A generator operating at 50Hz delivers 1.0pu power to an infinite bus through a transmission circuit in which resistance is ignored. A fault takes place reducing the maximum power transferable to 0.5pu. Whereas, before fault, this power was 2pu and after the clearance of the fault it is 1.15pu. By the use of equal area criterion determine the critical clearing angle. (JNTU Nov 04)

21. Discuss the general considerations and assumptions that are taken into account while studying transient stability. (JNTU Nov 04)

22. Write the state variable formulation of swing equations. (JNTU May 04)

23. Discuss the various techniques adopted to improve transient stability limit. (JNTU May 04)

24. List the assumptions made in the transient stability solution techniques. (JNTU Nov 03)

25. Derive the equal area criterion of stability and explain clearly how you can determine the stability limit of a synchronous motar when there is a sudden change in the mechanical load on the motar.

(JNTU Nov 02)

26. i. Derive the swing equation of a synchronous machine swinging against an infinite bus. State theassumptions made

ii. Indicate how wil you apply equal area criterion:a. to find the maximum additional load that can be suddenly added.b. In a two circuit transmission system, sudden loss of one circuit. (JNTU Nov 99)

27. For which one of the following types of motors, is the equal-area criterion for stability applicable?i. Three-phase synchronous motor ii. Three-phase induction motoriii. D.C. series motor iv. D.C. compound motor (IES 06)

28. A large generator is delivering 1.0 pu power to an infinite bus through a transmission network. The maximum powers which can be transferred for pre-fault, fault and post-fault conditions are 1.8 pu, 0.4 pu and 1.3 pu respectively. Find critical clearing angle. (IES 01)

29. Discuss why?i. Transient stability limit is lower than steady state stability limitii. The use of automatic reclosing circuit breakers improve system stabilityiii. A salient pole machine is more stable than a cylindrical rotor machine terminal voltage of the generator

(Eg) is held at 1.0 p.u and the voltage of infinite bus (E1) at 1.0 p.u. (IES 00)

30. An alternator with negligible damping is connected to an infinite bus. Write down its swing equation in usual form. How inertia constant H is defined here? Deduce the equal area criterion condition.

(IES 00)31. Consider the power system the values marked are per unit reactances and per unit voltages. The

generator was delivering 1.0 p.u. Power before a three phase fault occurs at P. The fault was cleared by opening the circuit breakers and isolating the faulty line in 5 cycles. generator has an inertia constant of 4.0 p.u.Using point by point method, with time interval of 0.05 sec. obtain the swing curve for a period of 0.2 sec.Assume f =50 Hz. (IES 99)

32. The maximum powers for pre-fault, during fault and post fault conditions are 1.5, 0.375 and 1.125 pu respectively. If d0=300, critical=670, calculate the value of acceleration or deceleration when d=750

(OU Nov 02)

33. Mention the applications of equal area criterion and its limitations (OU May 05)

34. List the factors that effects the transient stability of a power system (OU Jan 01)

35. i. Explain how the solution for swing equations obtained by point by point methodii. Station A transmits 50MW of power to station B through a tie line. The maximum steady state capacity

of the tie line is 100MW. Determine the allowable sudden load that can be switched on with out loss of stability (OU May 05)

36. State list of methods to improve transient stability (OU Apr 03)

37. What is swing curve and what are the equations used to solve a swing equation using step-by-step method. (OU Apr 03)

38. Find critical clearing angle using the following data. Initial power transfer 1 pu, maximum power limits under prefault, during fault and post fault conditions 2, 0.5 and 1.5 pu respectively

39. Discuss the procedure for solving the swing equation using point by point meyhod

40. How can the transient stability of a system be improved? Discuss the traditional as well as new approaches to the problem

41. 37. Plot the swing curve up to a time of 0.5 seconds for the system of problem shown in the fig below for i. Sustained faulti. Fault cleared by opening the circuit breakers at both ends of faulted line in 0.1 secondsinfinite bus

42. The system shown in fig above is provided with automatic reclosing circuit brakers. The fault is cleared by opening the circuit breakers of the faulted line in 0.1 seconds. The circuit breakers reclose after allowing a time of 0.2 seconds for the de-ionozation of the arc. Plot the swing curve upto a time of 0.5 seconds.

43. Two large generators A and B are connected through a network as shown below. The generator A has an inertia constant of 1.76 MJ/MVA on 100 MVA base and X’d=0.5 pu. The generator B has an inertia conatant of 14.1 MJ/MVA on 100 MVA base and X’’d=0.12pu. The reactances in the fig are also on 100 MVA and rated voltage base

i. Find the equivalent inertia constant to represent this two machine systemii. A three phase fault occurs on middle of one of the parallel circuits. Find the transfer reactance for

prefault, during fault and post fault conditions.iii. If Pi=0.60pu, EA=1.1pu, EB=1.0 pu, find the critical clearing angle for the above fault condition. Draw

power angle curves and show the accelerating and decelerating areas. For this system also plot the swing curves for a time of 0.5 seconds for a. Sustained faultb. Fault cleared in 0.1 seconds Pi=0.5pu, EA=1.05pu, EB=1.0pu

44. A 3-phase 50MVA, 50HZ generator has an angular momentum of 0.05MJs/elect degree and is loaded to 0.8pu. It is feeding an infinite bus through a transmission system.

7. SUBJECT DETAILS

7.2 POWER SYSTEM OPERATION AND CONTROL


7.2.2 Scope

7.2.3 Prerequisites

7.2.4 Syllabus

i. JNTU

ii. GATE

iii. IES


7.2.6 Websites


7.2.8 Journals


7.2.10 Session Plan




i. JNTU

ii. GATE

iii. IES


The main objective is to provide the students with an overview of the engineering and economic matters involved in designing, operating and controlling the power generation and transmission of a large scale, inter connected power system.

This subject is committed to the study of i. Analytical methods of arriving at the optimal operating strategies which must meet the minimum

standards of reliability i.e. continuity of supply and the problems in power systems like unit-commitment and load scheduling.

ii. Automatic control of power output of generators to maintain the scheduled frequency and automatic control of reactive power demand to maintain the desired voltage profile at the load end.

This course is introduced to enable the student master the process of simulation and modelling of the power system components and application of the simulation concepts learnt.

7.4.2 SCOPE

This subject is useful to train the under graduate in the latest techniques of analaysis of large scale power systems which is a similar need exists in the industry where a practising power system engineer is constantly faced with the challenge of the rapidly advancing field.

7.4.3 PREREQUISITES

The student is expected to have prior knowledge in circuit theory and electrical machines with special emphasis on laplace transforms, linear differential equations. Knowledge of optimization techniques, basic power systems and a first course in control theory is highly desirable.

7.4.4.i. SYLLABUS – JNTU

UNIT-I OBJECTIVE

The main objective of this unit is to study the analytical methods of arriving at the optimal strategies in power systems which must meet the minimum standards of reliability. It mainly focuses the attention on optimal allocation of real power at generator buses for minimizing the cost of generating real power (thermal stations).

SYLLABUS

Optimal operation of generators in all thermal power stations, heat rate curve, cost curve, incremental fuel and production costs, input and output characteristics, optimum generation allocation with line losses neglected.

UNIT-IIOBJECTIVE

The main objective of this unit is to focus the attention on optimal allocation of real power at generator buses including the effect of transmission line losses for minimizing the cost of generating real power (thermal stations).

SYLLABUS

Optimum generation allocation including the effect of transmission line losses, loss coefficients, general transmission line loss formula.

UNIT-IIIOBJECTIVE

This unit presents minimization of operating cost of hydrothermal system which is a dynamic optimization problem and the systematic coordination of the operation of a system of hydroelectric generation plants which is usually more complex than the scheduling of an all - thermal generation system.

SYLLABUS

Optimal scheduling of hydrothermal system: Hydro electric power plant models, scheduling problems, short term hydro thermal scheduling problem.

UNIT-IVOBJECTIVE

The objective of this unit is to study the modelling of synchronous generator in transient and steady state modes which are required for stability analysis of the power system and to acquire the knowledge on the modelling of prime-mover and excitation controllers which are used for the regulation of frequency and terminal voltage respectively for the purposes of stability analysis of the power systems.

SYLLABUS

Modelling of turbine, generator and automatic controllers : modelling of turbine: first order turbine model, block diagram representation of steam turbines and approximate linear models.

Modelling of generator ( steady state and transient models) : description of simplified network model of a synchronous machine (classical model), description of swing equation ( no derivation) and state-space ii-order mathematical model of synchronous machine.

Modelling of governor : mathematical modelling of speed governing system - derivation of small signal transfer function.

Modelling of excitation system : fundamental characteristics of an excitation system, transfer function, block diagram representation of IEEE type-1 model

UNIT-VOBJECTIVE

The objective of this unit is to acquire the knowledge on importance of frequency control, automatic load frequency control mechanism of single area system whose role is to maintain desired megawatt output of a

generator unit and assist in controlling the frequency of the larger interconnection. This unit also presents the analysis of ALFC loop in terms of static and dynamic responses.

SYLLABUS

Necessity of keeping frequency constant.

Definition of control area, single area control, block diagram representation of an isolated power system, steady state analysis, dynamic response, uncontrolled case.

UNIT-VIOBJECTIVE

The objective of this unit is to acquire the knowledge of frequency control of interconnected areas or power pools as today power systems are tied together with neighbouring areas to gain many advantages in brief mutual assistance, which are more important than those of isolated areas.SYLLABUS

Load frequency control of two area system, uncontrolled case and controlled case, tie line bias control.

UNIT-VIIOBJECTIVE

The objective of this unit is to acquire the knowledge on PI control for the single area system to yield zero steady state error and economic dispatch control.

SYLLABUS

Proportional plus integral control of single area and its block diagram representation, steady state response, load frequency control and economic dispatch control.

UNIT-VIIIOBJECTIVE

The objective of this unit is to study the compensation of the reactive power in power systems, some of the characteristics of power systems and their loads which deteriote the quality of supply and to identify those which can be corrected by compensation i.e by generation or absorption of a suitable quantity of reactive power.

SYLLABUS

Overview of reactive power control, reactive power compensation in transmission systems, advantages and disadvantages of different types of compensating equipment for transmission system, load compensation, specifications of load compensator, uncompensated and compensated transmission lines, shunt and series compensation.

7.4.4.2 GATE SYLLABUS

UNIT-IEconomic operation.

UNIT-IIEconomic operation.

UNIT-IIINot covered.

UNIT-IVSwing equation.

UNIT-VNot covered in syllabus, but asked questions from load frequency control.

UNIT-VINot covered in syllabus, but asked questions from tie line control.

UNIT-VIINot covered in syllabus, but asked questions from load frequency control.

UNIT-VIIIVoltage control.

7.4.4.3 IES SYLLABUS

UNIT-IOptimal system operation.

UNIT-IIOptimal system operation.

UNIT-IIINot covered in syllabus, but asked questions from hydro electric stations.

UNIT-IVSwing equation.

UNIT-VLoad frequency control.

UNIT-VILoad frequency control.

UNIT-VIILoad frequency control.



TEXT BOOKS

T1 Electrical Power Systems, C.L.Wadhwa, 3rd Edn., New Age International (P) Ltd, 1998.

T2 Modern Power System Analysis, I.J. Nagrath and D.P. Kothari, 2nd Edn., Tata Mc Graw-Hill Publishing Company Ltd.

REFERENCE BOOKS

R1 Power system analaysis, Hadi Sadat, Tata Mc Graw Hill Edition.

R2 Power System Dynamics: Stability and Control, K.R. Padiyar, 2nd Edn., B.S. Publications.

R3 Computer Modelling of Electrical Power Systems, J. Arrillaga, C.P. Arnold and B.J. Harker, 2nd Edn, John Wiley & Sons Publishers.

7.4.6 WEB SITES

1. www.sonton.ac.uk (university of southampton)2. www.berkely.edu (University of California, Berkely)3. www.ncsu.edu (North Carolina University)4. www.manchester.ac.uk (University of Manchester)5. www.unb.ca (University of New Brun Swick)6. www.umn.edu (University of Minnesota)7. www.iitb.ac.in (IIT, Bombay)8. www.iitk.ac.in (IIT, Kanpur)9. www.iitm.ac.in (IIT, Madras)10. www.iitd.ac.in (IIT, Delhi)

7.4.7 EXPERTS’ DETAILS

INTERNATIONAL

1. Name : Dr. B.F. WoolenbergDesignation : Professor

Department : Director of Graduate Studies,Office address : Center for Electric Energy, Director of University of Minnesota,Phone No. :Email : [email protected].

2. Name : Dr. Arthur R.Bergen,Designation : Professor

Department : Department of Electrical Engineering and Computer SciencesOffice address : University of California, BerkelyPhone No. :Email : www.eecs.berkely.edu

3. Name : Dr.M.S.Ei-MoursiDesignation : Professor

Department : Department of Electricla nd Computer EngineeringOffice address : University of New Brun Swick, Frederiction, NB E3B 5A3, CanadaPhone No. :Email : [email protected]

4. Name : Dr. B.TyagiDesignation : Professor

Department : Department of Electrical EngineeringOffice address : Harcourt Butler Technological Institute, Kanpur – 208016, IndiaPhone No. :Email : [email protected]

NATIONAL

1. Name : Dr. D.P. KothariDesignation : Professor

Department : Centre for Energy Studies,Office address : Deputy Director (Admin), IIT, DelhiPhone No. :Email : www.iitd.ac.in

2. Name : Dr. I.J.NagrathDesignation : Professor

Department : Department of Electrical EngineeringOffice address : Deputy Director, BITS, PilaniPhone No. :Email : www.bits-pilani.ac.in

REGIONAL

1. Name : Dr. A.V.R.S. SarmaDesignation : Associate Professor

Department : Department of Electrical and Electronics EngineeringOffice address : College of Engineering, Osmania University

Phone No. :Email : [email protected]

2. Name : Dr. B.V. Sankar Ram Designation : Professor and HOD

Department : Department of Electrical and Electronics EngineeringOffice address : JNTU, Kukatpalli, HyderabadPhone No. :Email : [email protected]

7.4.8 JOURNALS


2. Name of the Journal : IEEE Transactions on Power DeliveryPublisher : IEEE Publications

3. Name of the Journal : IEEE Journal on Computer Application in PowerPublisher : IEEE Publications

4. Name of the Journal : Power Engineering JournalPublisher : IEEE Publications

5. Name of the Journal : IEEE transactions on Power and EnergyPublisher : IEEE Publications

6. Name of the Journal : IEEE transactions on Power Apparatus and SystemsPublisher : IEEE Publications

7. Name of the Journal : IEEE Transactions on Automatic Control

Publisher : IEEE Publications

8. Name of the Journal : Electrical IndiaPublisher : Chary Publications Pvt Ltd

9. Name of the Journal : Electrical Engineering UpdatesPublisher : Institution of Engineers (India) Publishers

10. Name of the Journal : Journal of Institution of Engineers, India.

Publisher : Institution of Engineers (India) Publishers


1. Title : Supply Shortage Hedging: Estimating the Electrical Power Margin for Optimizing Financial and Physical Assets With Chance-Constrained Programming

Author : Zorgati, R.; van Ackooij, W.; Apparigliato, R.Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 533-540


http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=59

2. Title : Frequency-Adaptive Power System Modeling for Multiscale Simulation of Transients

Author : Feng Gao; Strunz, K.Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 561-571

3. Title : Maiden Application of Bacterial Foraging-Based Optimization Technique in Multi area Automatic Generation Control

Author : Nanda, J.; Mishra, S.; Saikia, L.C.Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 602-609

4. Title : A Refined Hilbert–Huang Transform With Applications to Interarea Oscillation Monitoring

Author : Laila, D.S.; Messina, A.R.; Pal, B.C.Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 610-620

5. Title : Determination of Capacity Benefit Margin in Multiarea Power Systems Using Particle Swarm Optimization

Author : Ramezani, M.; Haghifam, M.-R.; Singh, C.; Seifi, H.; Moghaddam, M.P.

Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 631-641

6. Title : A Proposal for Concurrent Estimation of Static and Dynamic Nonlinearity of ADC

Author : Vora, S.C.; Satish, L.Journal : IEEE Transactions on Power Delivery Vol., Year & Page No. : April 2009, Volume: 24, Issue: 2, Page(s): 524-530

7. Title : A Novel Single-Phase Adaptive Reclosure Scheme for Transmission Lines With Shunt Reactors

Author : Jiale Suonan; Wenquan Shao; Guobing Song; Zaibin JiaoJournal : IEEE Transactions on Power DeliveryVol., Year & Page No. : April 2009, Volume: 24, Issue: 2, Page(s): 545-551

8. Title : A Practical Guide to Harmonic Frequency Interference Affecting High-Voltage Power-Line Carrier Coupling Systems

Author : Zorgati, R.; van Ackooij, W.; Apparigliato, R.Journal : IEEE Transactions on Power DeliveryVol., Year & Page No. : April 2009, Volume: 24, Issue: 2, Page(s): 630-641

9. Title :Author : Zorgati, R.; van Ackooij, W.; Apparigliato, R.Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 533-540

10. Title : Analytical Description of the Load-Loss Asymmetry Phenomenon in Three-Phase Three-Limb Transformers

Author : Escarela-Perez, R.; Kulkarni, S.V.; Alvarez-Ramirez, J.; Kaushik, K.Journal : IEEE Transactions on Power DeliveryVol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 695-702

11. Title : A Hybrid Winding Model of Disc-Type Power Transformers for Frequency Response Analysis

Author : Shintemirov, A.; Tang, W.H.; Wu, Q.H.Journal : IEEE Transactions on Power Delivery




















Vol., Year & Page No. : May 2009, Volume: 24, Issue: 2, Page(s): 730-739


SESSION PLAN

Sl.No.




UNIT-I – ECONOMIC OPERATION OF POWER SYSTEMS – 1 (No. of Lectures – 05)

1Optimal operation of generators in all thermal power stations

Introduction L1T1-Ch19 (P:646)T2-Ch7 (P:242)R1-Ch7 (P:257)

GATEIES

2

Heat rate curve Cost curve Incremental fuel and production costsInput and output characteristics

Heat rate curve Cost curve Incremental fuel and production costsInput and output characteristics

L2T1-Ch19 (P:)649T2-Ch7 (P:243)R1-Ch7 (P:267)

3Optimum generation allocation with line losses neglected

LagrangianCoordination Equation

L3T1-Ch19 (P:650)T2-Ch7 (P:245)R1-Ch7 (P:264)

Problems on optimum generation allocation with line losses neglected

L4T1-Ch19 (P:657)T2-Ch7 (P:246)R1-Ch7 (P:272)

Problems on optimum generation allocation with line losses neglected

L5T1-Ch19 (P:658)T2-Ch7 (P:249)R1-Ch7 (P:276)

UNIT – II – ECONOMIC OPERATION OF POWER SYSTEMS – 2 (No. of Lectures – 06)

4

Optimum generation allocation including the effect of transmission line losses

Penalty factorIncremental transmission lossExact coordination equation

L6T1-Ch19 (P:661, 653)T2-Ch7 (P:260)R1-Ch7 (P:275) GATE

IESProblems on optimum generation allocation with line losses

L7T1-Ch19 (P:659)T2-Ch7 (P:263)R1-Ch7 (P:278)

5General transmission line loss formulaLoss coefficients

Derivation of transmission loss formula Assumptions

L8T1-Ch19 (P:669)T2-Ch7 (P:265)R1-Ch7 (P:289)

Problems on B-Coefficients L9T1-Ch19 (P:670)T2-Ch7 (P:267)R1-Ch7 (P:293)

Exercise problems L10T1-Ch19 (P:680)T2-Ch7 (P:284)R1-Ch7 (P:297)

Exercise problems L11T1-Ch19 (P:681)T2-Ch7 (P:281)R1-Ch7 (P:300)

UNIT – III – HYDROTHERMAL SCHEDULING (No. of Lectures – 05)

6 Optimal scheduling of hydrothermal system:

IntroductionLong range hydro scheduling

L12 R3-Ch7 (P:242)

Sl.No.




Hydroelectric power plant models

Short range hydro scheduling Incremental water rate versus power output.

7 Scheduling problemsTypes of scheduling problemsScheduling energyProblems

L13 R3-Ch7 (P:243) IES

8Short term hydro-thermal scheduling problem

Fundamental systemMathematical formulation

L14T2-Ch7 (P:276)R6-Ch7

Solution technique AlgorithmHydro thermal system with hydraulic constraints

L15T2-Ch7 (P:277)R6-Ch7

Problem on hydro thermal scheduling

L16T2-Ch7 (P:285)R6-Ch7

UNIT – IV – MODELLING OF TURBINE, GENERATOR AND AUTOMATIC CONTROLLERS(No. of Lectures – 12)

9

Modeling of turbine: First order turbine modelBlock diagram representation of steam turbines

Small signal transfer function L17T2-Ch8 (P:295)R2-Ch4 (P:113)R3-Ch7 (P:229)

10Approximate linear models

Tandem compound single and double reheat turbines Cross compound single and double reheat turbinesBlock diagram representations

L18R2-Ch4 (P:132)R3-Ch7 (P:232)

11

Modeling generator: Description of simplified network model of synchronous machine

Introduction Modelling of synchronous machine

L19T2-Ch4 (P:94)R2-Ch7 (P:232)R3-Ch7 (P:231)

12Description of swing equation

Description of swing equation, swing equation for multi-machine system, for machines swinging coherently, for non coherent machines, problems on swing equation

L20T2-Ch12 (P:436)R2-Ch2 (P:10)

GATEIES

13States space II-order mathematical model of synchronous machine

Generator load model, derivation and block diagram representation

L21T2-Ch12 (P:435)R2-Ch2 (P:43)

GATEIES

14 Modeling governor Block diagram representation of automatic load frequency and

L22 T2-Ch8 (P:292)R2-Ch4 (P:114) GATE

Sl.No.




voltage control loops of synchronous generatorSmall signal analysis

R3-Ch7 (P:239)IES

15

Mathematical modeling of speed governing systemDerivation of small signal transfer function

Functional diagram Block diagram representation of speed governor system

L23T2-Ch8 (P:321)R2-Ch4 (P:136)R3-Ch7 (P:240)

GATEIES

16

Excitation system modeling :Fundamental characteristics of excitation system

Objective of excitation systemSome definitionsFunctioning of the exciterExciter ceiling voltageExciter responseDC, AC and static excitation systemsFunctional block diagram of excitation control system

L24R2-Ch4 (P:119)

17 Transfer function

Terminal voltage transducer and load compensatorExciters and voltage regulators Excitation system stabilizer and transient gain reduction Power system stabilizer

L25 R2-Ch4 (P:115)

Excitation system standard block diagramDC excitation system, derivation of transfer functionAC excitation system, saturation characteristics

L26 R2-Ch4 (P:117)

Static excitation systemBrushless excitation

L27R2-Ch4 (P:125)R3-Ch7 (P:237)

18Block diagram representation of IEEE type-1 model

Mathematical model of the system

L28R2-Ch4 (P:141)R3-Ch7 (P:242)

UNIT – V – SINGLE AREA LOAD FREQUENCY CONTROL (No. of Lectures – 05)

19 Necessity of keeping frequency constant

IntroductionGovernor characteristics Load frequency problemSchematic diagram of L-F and Q-V regulators of turbo generator Cross coupling between control loops

L29 T1-Ch20 (P:682, 685)T2-Ch8 (P:320)R1-Ch12 (P:527)

IES

Sl.No.




20 Definition of control area, single area control Block diagram representation of isolated power system

Reasons for limits on frequencyTurbine speed governing systemBlock diagram model of load frequency control

L30T1-Ch20 (P:686-691)T2-Ch8 (P:293)R1-Ch12 (P:532)

21 Steady state analysis

Steady state analysis L31T2-Ch8 (P:297)R7-Ch12 (P:466)

Problems on load frequency control

L32T1-Ch20 (P:696)T2-Ch8 (P:300)R1-Ch12 (P:469)

GATEIES

22Dynamic response Uncontrolled case

Problems on dynamic response L33 T2-Ch8 (P:325) IES

UNIT – VI – TWO AREA LOAD FREQUENCY CONTROL (No. of Lectures – 04)

23

Load frequency control of two area systemUncontrolled case and controlled case

Mathematical modeling of load frequency control of two area systemSynchronizing coefficient Static response (Uncontrolled case)

L34

T2-Ch8 (P:307)R7-Ch12 (P:545)

GATEIES

Dynamic response (Uncontrolled case)The Controlled caseArea control errorChange in tie line power due to step load change in area -1

L35T2-Ch8 (P:301)R1-Ch12 (P:547)

Composite block diagram representation of two area load frequency controlProblems on two area load frequency control

L36T2-Ch8 (P:311)R1-Ch12 (P:548)

24 Tie line bias control

Tie line loading frequency characteristicsTie line bias control of two area and multi area systems Summary of tie line frequency control

L37T1-Ch20 (P:685)R1-Ch12 (P:549)

UNIT – VII – LOAD FREQUENCY CONTROLLERS (No. of Lectures – 04)

25

Proportional plus integral control of single area and its block diagram representation, steady state response

Control area conceptArea control errorDynamic response of load frequency controller with and without integral control action.

L38

T2-Ch8 (P:303)

IES

26

Load frequency control and economic dispatch control

Load frequency control and economic dispatch control

L39T2-Ch8 (P:305)

IES


L40T2-Ch8 (P:324) GATE

IES


L41T2-Ch8 (P:325) GATE

IES

UNIT – VIII – REACTIVE POWER CONTROL (No. of Lectures – 11)

27Overview of reactive power control

Overview of reactive power control

L42T1-Ch10 (P:222)T2-Ch5 (P:158, 173)

28

Reactive power compensation in transmission systemsAdvantages and disadvantages of different types of compensating equipment for transmission systems

Generation and absorption of reactive power Types of compensators Reactive power injection Static VAR generator Rotating VAR generatorObservations Shunt capacitors and reactors

L43 T2-Ch5 (P:175)GATE

IES

Series capacitors Comparison between series and shunt capacitors Transmission lines CablesTransformers

L44T1-Ch10 (P:225)T2-Ch5 (P:177)

GATEIES

Tap changing transformers Problem

L45T1-Ch10 (P:229)T2-Ch5 (P:177)

GATEIES

Combined use of tap-changing transformers and reactive power injection Problem

L46 T2-Ch5 (P:178)GATE

IES

Booster transformers Phase shift transformersProblemOver all view on advantages and disadvantages of different types of compensating equipment for transmission system

L47T1-Ch10 (P:231) GATE

IES

Problems on reactive power L48 T1-Ch10 (P:233) GATE

UNIT – VII – LOAD FREQUENCY CONTROLLERS (No. of Lectures – 04)

generation and absorption T2-Ch5 IES

29Load compensationSpecifications of load compensator

Power factor correction Improvement of voltage regulation Load balancing

L49 T1-Ch21 (P:694)

Study of voltage regulation using short circuit capacity Problem

L50 T1-Ch21 (P:701)

30Uncompensated transmission lines

Uncompensated transmission lines

L51 T1-Ch21 (P:706)

Symmetrical LineRadial line with asynchronous load

L52 T1-Ch21 (P:710)

31Compensated transmission linesShunt compensation

Compensation of linesSurge impedance compensation Compensation by sectioning Line length compensation

L53 T1-Ch21 (P:714, 723) IES

32 Series compensation

Effect of series compensation on surge impedance loading Comparison between shunt and series compensation

L54 T1-Ch21 (P:714) IES

Active shunt compensator V-curves for the condenser Condenser out putUse of condenser for HVDC line Static compensators

L55 T1-Ch21 (P:725) IES

Thyristor controlled reactorBasic circuits Control of Basic TCR 3-Phase arrangement of TCRSteady state performance

L56 T1-Ch21 (P:727) IES

Thyristor switched capacitors Saturated reactors FACTSStatic condenser Advanced thyristor controlled series compensation Thyristor controlled phase shifting transformer

L57 T1-Ch21 (P:733, 737)

IES

Problems on reactive power control

L58T1-Ch10 (P:702)T2-Ch5 (P:243, 245)

GATEIES


1. Title : Economic Consequences of Alternative Solution Methods for Centralized Unit Commitment in a day-ahead Electricity Markets

Author :Journal : IEEE Transactions on Power SystemsVol., Year & Page No. : May 2008, Volume: 23, Issue: 2

2. Title : Voltage and Reactive Power Control in Systems with Synchronous Machine Based Distributed Generation

Author : FA Viawan and D. KarlssonJournal : IEEE Transactions on Power SystemsVol., Year & Page No. : April 2008, Volume: 23, Issue: 2

3. Title : Dual Function Neuron External Controller for a Static VAR Compensator

Author : G.K. Venayagamoorthy and S.R. JettiJournal : IEEE Transactions on Power SystemsVol., Year & Page No. : April 2008, Volume: 23, Issue: 2

4. Title : Optimal Reactive Compensator in Power Systems Under Assymetrical and non-sinusoidal Conditions

Author : T.V. Sekara, J.C. Mikulovic and Jeddar DjurisicJournal : IEEE Transactions on Power SystemsVol., Year & Page No. : April 2008, Volume: 23, Issue: 2

5. Title : Decoupled Voltage and Frequency Controller for Isolated Asynchronous Generators Feeding 3-phase Four Wire Loads

Author : G.K. Kasal and B. SinghJournal : IEEE Transactions on Power SystemsVol., Year & Page No. : April 2008, Volume: 23, Issue: 2












UNIT – I

1. Describe in detail, with suitable examples, the methods of optimum scheduling of Generation of power from a thermal station. (JNTU May 09)

2. a. Define in detail the following:i. Control variables ii. Disturbance variables iii. State variables.

b. Draw incremental fuel cost curve. (JNTU May 09)

3. A constant load of 300 MW is supplied by two 200 MW generators 1 and 2, for which the respective incremental fuel costs are:

With power PG in MW and costs C in Rs/hr. Determine:a. The most economical division of load between the generators.b. The saving in Rs./ day there by obtained compared to equal load sharing between two generators.

(JNTU May 09)

4. Incremental fuel costs in rupees per megawatt hour for two units are given by and

the maximum and minimum loads on each unit are to 25MW and 120MW,

respectively. Determine the incremental fuel cost and the allocation of load between units for minimum cost when the loads are:a. 100MW b. 150MW (JNTU May 09)

5. a. Explain how the incremental production cost of a thermal power station can be determined.b. Explain the various factors to be considered in allocating generation to different power stations for

optimum operation. (JNTU May 09)

6. a. Describe in detail, with suitable examples, the methods of optimum scheduling of generation of power from a thermal station.

b. What is Production cost of power generated and incremental fuel rate?c. Write the expression for hourly loss of economy resulting from error in incremental cost representation.

(JNTU May 09)

7. Explain optimal load flow solution without inequality constraints. (JNTU May 09)

8. Discuss optimal power flow problems with and without inequality constraints. How are these problems solved? (JNTU May 09)

9. Draw the flow chart for obtaining optimal scheduling of generating units by neglecting the transmission losses. (JNTU May 09)

10. a. Explain the significance of equality and inequality constraints in the economic allocation of generation among different plants in a system.

b. Derive the condition for economic scheduling of generators in a plant. (JNTU May 09)

11. a. State what is meant by base-load and peak-load stations. Discuss the combined hydroelectric and steam station operation.

b. Discuss about the incremental fuel cost and production cost. (JNTU Nov 08)

12. i. Derive an expression for optimal allocation of generators with in a power plant.

ii. The incremental fuel inputs for a two unit steam plant are given by = 0.08p1 + 15 Rs/Mw - Hr.

= 0.08p2 + 20 Rs/Mw - Hr.

Find the loss in operating economy if the two units share a load of 300 MW equally instead of operating in an optimum way. (JNTU Feb 08, 07)

13. i. Explain the following terms with reference to power plants: Heat input power output curve, Heat rate input, Incremental input, Generation cost and Production cost.

ii. What are the methods of scheduling of generation of steam plants? Explain their merits and demerits?(JNTU Feb 08, Nov 07)

14. i. Derive the conditions to be satisfied for economic operation of a loss less power system.ii. 150 MW, 220 MW and 220 MW are the ratings of three units located in a thermal power station. Their

respective incremental costs are given by the following equations:

= Rs(0.11p1 + 12)

= Rs(0.1p3 + 13)

= Rs(0.095p2 + 14)

Where P1, P2 and P3 are the loads in MW. Determine the economical load allocation between the three units, when the total load on the station is i. 350 MW ii. 500 MW.

(JNTU Feb 08, Nov 06, 05, 03)

15. i. Explain in detail the terms production costs, total efficiency, incremental efficiency and incremental rates with respect to thermal power plant.

ii. Give step by step procedure for computing economic allocation of generation in a thermal station.(JNTU Feb 08, Mar 06, Apr 05)

16. Incremental fuel cost in Rupees per mega watt hour for two units comprising a plant are given by the following equations.

Assume that both units are operating at all times, that total load varies from 40 to 200 MW and the maximum and minimum loads on each unit are to be 125 and 20 MW respectively. Find the incremental fuel cost & the allocation of loads between units for the minimum cost of various total loads. Derive the formula used. (JNTU Nov 07)

17. i. Explain how the incremental production cost of a thermal power station can be determined.ii. Explain the various factors to be considered in allocating generation to different power stations for

optimum operation. (JNTU Mar 06, Apr 05, Nov 07, 04, 03, Oct 02)

18. i. Describe in detail, with suitable examples, the methods of optimum scheduling of generation of power from a thermal station.

ii. What is Production cost of power generated and incremental fuel rate?iii. Write the expression for hourly loss of economy resulting from error in incremental cost representation.

(JNTU Nov 07, 06)

19. i. What is an incremental fuel cost? How is it used in thermal plant operation? ii. Name the components of production cost and explain.

(JNTU Feb 07, Mar 06, Nov 07, 05, 04)

20. Discuss about the optimum generator allocation without line losses.(JNTU Feb 07, Nov 04, Apr 04)

21. i. Explain the significance of equality and inequality constraints in the economic allocation of generation among different plants in a system

ii. Derive the condition for economic scheduling of generators in a plant. (JNTU Nov 06, Mar 06)

22. Write short notes on: Physical interpretation of co-ordination equation. (JNTU Nov 06, 04, 03, Mar 06)

23. The incremental fuel costs for two plants are given by ; .

Where C is in and P is in MW. If both units operate at all time and maximum and minimum load on each unit are 100 MW and 20 MW respectively. Determine the economic operating schedule of the plant for loads of 40 MW, 120 MW and 180 MW. (JNTU Nov 04)

24. i. A power System consists of two, 125 MW units whose input cost data are represented by the equations:C1 = 0.04 P12 + 22 P1 + 800 Rupees/hourC2 = 0.045 P22 + 15 P2 + 1000 Rupees/hourIf the total received power PR = 200 MW. Determine the load sharing between units for most economic operation.

ii. Discuss the general problem of economic operation of large interconnected areas.(JNTU Nov 04, 03)

25. What are the methods of scheduling of generation of steam plants? Explain their merits and demerits?(JNTU Nov 04)

26. i. Derive the coordination equations for economic scheduling including the effect of network losses in a purely thermal system and explain the -iteration method of sulving them with the help of flow chart.

ii. What is load factor and state the criterion for economic operation of power system.(JNTU Nov 04)

27. A power System consists of two, 125 MW units whose input cost data are represented by the equations:C1 = 0.04 P12 + 22 P1 + 800 Rupees/hourC2 = 0.045 P22 + 15 P2 + 1000 Rupees/hourIf the total received power PR = 150 MW. Determine the load sharing between units for most economic operation. (JNTU Nov 03)

28. Explain the terms:

i. Heat rate curve ii. Cost curve iii. Incremental fuel cost iv. Incremental production cost. (JNTU Nov 02, Apr 04, Oct 02, IES 93)

29. A load centre is at an equidistant from the two thermal generating stations G1 and G2 as shown in the figure. The fuel cost characteristics of the generating stations are given by F1= a + bP1 + cP12 Rs/hourF1= a + bP2 + 2cP22 Rs/hourWhere P1 and P2 are the generation in MW of G1and G2 respectively.For most economic generation to meet 300 MW of load, P1and P2, respectively, are i. 150, 150 ii. 100, 200 iii. 200, 100 iv. 175, 125 (GATE 05)

30. Incremental fuel costs (in some appropriate unit) for a power plant consisting of three generating units are IC1 = 20 + 0.3 P1

IC2 = 30 + 0.4 P2

IC3 = 30Where P1 is the power in MW generated by unit i, for i = 1, 2 and 3. Assume that all the three units are operating all the time. Minimum and maximum loads on each unit are 50 MW and 300 MW respectively. If the plant is operating on economic load dispatch to supply the total power demand of 700 MW, the power generated by each unit is i. P1 = 242.86 MW; P2= 157.14 MW; and P3= 300 MWii. P1 =157.14 MW; P2 = 242.86 MW; and P3= 300 MWiii. P1 = 300.0 MW; P2 = 300.0 MW; and P3= 100 MWiv. P1 = 233.3 MW; P2 = 233.33 MW; and P3= 233.4 MW (GATE 03)

31. A power system has two generators with following cost curvesGenerator 1: C1 (PG1) = 0.006 PG12 + 8PG1 + 350 (Thousand Rs/ hr)Generator 2: C2 (PG2) = 0.009 PG22 + 7PG2 + 400 (Thousand Rs/ hr)The generator limits are 100 Mw PG1 650 Mw 50 Mw PG2 500 MwA load demand of 600 Mw is supplied by the generator in an optimal manner. Neglecting losses in the transmission network determine optimal generation of each generator (GATE 01)

32. In a power system the fuel inputs per hour of plants 1 and 2 are given asF1 = 0.20P12 + 30P1 + 100 Rs/ hrF2 = 0.25 P22 + 40 P2 + 150 Rs/ hrThe limits of generators are 20 < P1 < 80 Mw 40 < P2 < 200 MwFind the economic operating schedule of generation, if the load demand is 130 MW, neglecting transmission losses. (GATE 98)

33. The incremental cost characteristics of two generators delivering 200 MW are as follows

For economic operation, the generations P1 and P2 should be i. P1=P2=100 MW ii. P1=80MW, P2=120MW

iii. P1= 200 MW, P2=0 MW iv. P1=120 MW, P2=80 MW (GATE 00)

34. The fuel inputs of plants 1 and 2 are given as F1 = 0.2P12 + 40 P1 + 120 Rs/ hr F2 = 0.25P22 + 30 P2 + 150 Rs/ hrDetermine the economic operating schedule and the corresponding cost of generation if the maximum and minimum loading of each machine is 100 MW and 25 MW, the demand is 180MW and transmission losses are neglected. If the load is equally shared by both units, determine the saving obtained by loading the units as per incremental cost. (IES 03)

35. The cost function of a 50 MW generator is given by (Pi is the generator loading) F(Pi) = 225 + 53 Pi + 0.02 Pi 2 When 100% loading is applied, the incremental fuel cost (IFC) will be i. Rs. 55 per MWh ii. Rs. 55 per MW iii. Rs. 33 per MWh iv. Rs. 33 per MW (IES 00)

36. The incremental generating costs of generating costs of two generating units are given by IC1 = 0.1 X +10 Rs./MWhIC2 = 0.15 Y + 18 Rs./MWhWhere X and Y are power (in MW) generated by th e two units. For a total demand of 300MW, the value (in MW) of X and Y will be respectively.i. 172 and 128 ii. 128 and 172 iii. 175 and 125 iv. 200 and 100 (IES 97)

37. The incremental cost characteristic of the two units in a plant areIC1 = 0.1 P1 + 8.0 Rs./MWhIC2 = 0.15 P2 +3.0 Rs./MWhWhen the total load is 100 MW, the optimum sharing of load is P1 P2i. 40 MW 60 MWii. 33.3 MW 66.7 MWiii. 60 MW 40 MWiv. 66.7 MW 33.3 MW (IES 96)

38. Consider the following three incremental cost curves.PG1 = - 100 + 50 IC1 - 2 (IC1)2 PG2 = - 150 + 60 IC2 - 2.5 (IC2)2PG3 = - 80 + 40 IC3 - 1.8 (IC3)2Where IC s are in Rs/ Mwh and PGS are in MW. The total load at a certain hour of the day is 400 MW. Neglect transmission loss and find optimum values of generation. i.e. PG1, PG2 and PG3. (IES 95)

39. The incremental fuel cost for two generating units are given by I C1 = 25 + 0.2 PG1

I C2 = 32 + 0.2 PG2

where PG1 and PG2 are real power generated by the units. The economic allocation for a total load of 250 MW, neglecting transmission loss is given by i. PG1 = 140.25 MW, PG2 = 109.75 MW ii. PG1 = 109.75 MW, PG2 = 140.25 MWiii. PG1 = PG2 = 125 MWiv. PG1 = 100 MW, PG2 = 150 MW (IES 95)

40. A constant load of 300 Mw is supplied by two 200 MW generators, 1 and 2 for which the respective

incremental fuel costs are , with

parameters P in MW and costs F in Rs/ hr. Determine

i. The most economical division of load between the generators (IES 94)ii. The saving in Rs/ day there by obtained compare the equal load sharing between generators.

41. A power plant has three units with the following input-output characteristics:Q1=0.002 P12 + 0.86 P1+ 20 tons/hourQ2=0.004 P22 + 1.08 P2 + 20 tons/hourQ3=0.0028 P32 + 0.64 P3 + 36 tons/hourWhere P1, P2 and P3 are the generating powers in MW. The fuel cost is Rs 25 per ton. The maximum and minimum possible generation for each unit are 120 MW and 39 MW respectively. Find the optimal scheduling for a total load of 200 MW. (IES 91)

UNIT – II

1. a. Explain with diagram the physical interpretation of co-ordination equation.b. Give various uses of general loss formula and state the assumptions made for calculating Bmn

coefficients. (JNTU May 09)

2. A simple two-plant system have the IC’s are dC1 / dPG1 = 0.01 PG1 + 2.0dC2 / dPG2 = 0.01 PG2 + 1.5 and the total load on the system is distributed optimally between two stations as PG1 = 60MW and PG2 = 110MW, corresponding l = 2.6 and the loss coefficients of the system are given as P Q Bpq1 1 0.00151 2 -0.00152 2 0.0025Determine the transmission loss. (JNTU May 09)

3. A power system is operating an economic load dispatch with a system λ of 60 Rs./MWh. If raising the output of plant-2 by 100kW (while the other output kept constant) results in increased power losses of 12 kW for the system. What is approximate additional cost per hour, if the output of this plant is increased by 1MW. (JNTU May 09)

4. a. Incremental fuel cost in Rupees per mega watt hour for two units comprising a plant are given by the following equations.

Assume that both units are operating at all times, that total load varies from 40 to 200 MW and the maximum and minimum loads on each unit are to be 125 and 20 MW respectively. Find the incremental fuel cost & the allocation of loads between units for the minimum cost of various total loads. Derive the formula used.

b. Discuss the costs associated with hydro plants. (JNTU May 09)

5. a. Explain with diagram the physical interpretation of co-ordination equation.b. Give various uses of general loss formula and state the assumptions made for calculating Bmn

coefficients. (JNTU May 09)

6. a. Derive the conditions to be satisfied for economic operation of a loss less power system.b. 150 MW, 220 MW and 220 MW are the ratings of three units located in a thermal power station. Their

respective incremental costs are given by the following equations:dc1/dp1 = Rs(0.11p1 + 12);dc3/dp3 = Rs(0.1p3 + 13)dc2/dp2 = Rs(0.095p2 + 14)Where P1, P2 and P3 are the loads in MW. Determine the economical load allocation between the three units, when the total load on the station isi. 350 MW ii. 500 MW. (JNTU Nov 08)

7. Give algorithm for economic allocation of generation among generators of a thermal system taking into account transmission losses. Give steps for implementing this algorithm, and also derive necessary equations. (JNTU Nov 08)

8. The equations of the input costs of three power plants operating in conjunction and supplying power to a system network are obtained as follows: C1 = 0.06 P2

1 + 15 P1 + 150 Rupees/hourC2 = 0.08 P2

2 + 13 P2 + 180 Rupees/hourC3 = 0.10 P2

3 + 10 P3 + 200 Rupees/hour.The incremental loss-rates of the network with respect to the plants 1, 2 and 3 are 0.06, 0.09 and 0.10 per MW of generation, respectively. Determine the most economical share of a total load of 120 MW which each of the plants would take up for minimum input cost of received power is Rupees per mMWH. (JNTU Nov 08)

9. The incremental production cost of two plants are given by :(IPC)1 = (0.07)P1 + 16Rs./MWh(IPC)2 = (0.08)P2 + 12Rs./MWh.The loss coefficients of the system are given by B11 = 0.001; B12 = B21 = -0.005 and B22 = 0.0024. The total load to be met is 150 MW, determine economic operating schedule if the transmission line losses are coordinated and the losses are included but not co-ordinated. (JNTU Feb 08)

10. What is incremental transmission loss and derive the general transmission loss formula.(JNTU Feb 08)

11. The incremental costs in Rs. Per M.W-Hr. for two units in a plant are given by

;

The minimum and maximum generation on each unit are to be 20 MW and 125 MW respectively. Determine the economic allocation between the units for a total load of 150 MW.

(JNTU Feb 08)

12. Develop the loss formula coefficients for a two plant system. State the assumptions made.(JNTU Nov 07)

13. The transmission loss coefficients in p.u. on a base of 100 MVA are given by

14. The three plants, A, B and C supply powers of PA = 100MW, PB = 200MW, PC= 300MW, into the network. Calculate the transmission loss in the network in MW and the incremental losses with respect to plants A, B, C. (JNTU Nov 07)

15. Give algorithm for economic allocation of generation among generators of a thermal system taking into account transmission losses. Give steps for implementing this algorithm, and also derive necessary equations. (JNTU Nov 07, 04)

16. Discuss the various constraints to be considered for economic load dispatch problem.i. Discuss and define the loss formula coefficients.ii What is the objective in economic scheduling? (JNTU Feb 07, Nov 06, 05)

17. The equations of the input costs of three power plants operating in conjunction and supply power to a system network are obtained as follows:C1 = 0.06P12 + 15 P1 + 150 Rupees/ hourC2 = 0.08P22 + 13 P2 + 180 Rupees/ hourC3 = 0.10P32 + 10 P3 + 200 Rupees/ hourThe incremental loss-rates of the network with respect to the plants 1, 2 and 3 are 0.06, 0.09 and 0.10 per MW of generation, respectively. Determine the most economical share of a total load of 120 MW which each of the plants would take up for minimum input cost of received power is Rupees per MWH.


18. Assuming any relevant data and notation, derive the transmission loss formula.(JNTU Feb 07, Nov 04, Apr 04)

19. Give various uses of general loss formula and state the assumptions made for calculating Bmn

coefficients. (JNTU Nov 06)

20. i. The incremental costs for two generating plants are IC1 = 0.1 P1 + 20 Rupees/MW hourIC2= 0.1 P2+ 15 Rupees/MW hourWhere P1 and P2 are in MW. The loss coefficients (Bmn) expressed in MW-1 unit are B11 = 0.001, B22 = 0.0024, B12 = B21 = - 0.0005. Compute the economical generation scheduling corresponding to the Lagrangian multiplier = 25 Rs. / MW hr and the Corresponding system load that can be met with. If the total load is 150 MW, taking 5% change in the value of λ, what should be the value of λ in the next iteration?

ii. What are the assumptions made in deriving the loss coefficients? (JNTU Mar 06, Nov 04, 02)

21. i. Describe the need for co-ordination of different power stations.ii. What are Bmn coefficients and derive them. (JNTU Nov 05)

22. The incremental fuel costs for two plants are given by

;

The system is operating at the optimum condition with p1 = p2 = 100MW and = 0.2. Find

the penalty factor of plant 1 and the incremental cost of received power. (JNTU Nov 03, 02)

23. Discuss in detail the optimum load dispatch problem of two identical generators connected through a transmission link by considering the transmission losses into account.

(JNTU Nov 02, Apr 04, Oct 02, IES 93)

24. The fuel inputs to two plants are given byF1 = 0.015P1

2 + 16P1 + 50 and F2 = 0.025P1

2 + 12P2 + 30.

The loss coefficients of the system are given by B11 = 0.005; B12=-0.0012 and B22 = 0.002. The load to be met is 200 Mw. Determine the economic operating schedule and the corresponding cost of generation if the transmission line losses are coordinated. (JNTU Nov 02)

25. A system consists of two plants connected by a tie line and a load is located at plant 2. When 100 MW are transmitted from plant 1, a loss of 10MW takes place on the tie-line. Determine the generation schedule at both the plants and the power received by the load when l for the system is Rs.25 per Megawatt hour and the incremental fuel costs are given by the equations :

= 0.03P1 + 17 Rs/M whr = 0.06P2 + 19 Rs/Mw-hr (JNTU Nov 02)

26. In terms of power generation and Bmm coefficients, the transmission loss for a two-plant system is (Notations have their usual meaning). (IES 00)i. P1

2B11 + 2 P1P2B12 + P2

2B22 ii. P1

2B11 - 2 P1P2B12 + P22B22

iii. P22B11 + 2 P1P2B12 + P1

2B22 iv. P1

2B11 + P1P2B12 + P2

2B22

27. The power generated by two plants are:P1 = 50 MW, P2 = 40 MW, the loss coefficients are B11 = 0.001, B22 = 0.0025 and B12 = -0.0005 then power loss will be i. 5.5 MW ii. 6.5 MW iii. 4.5 MW iv. 8.5 MW (IES 97)

28. If 100 MW is transmitted from Plant-1 to the load

a transmission loss of 10 KW incurred. Find the required generation for each plant and the power received by the load when the system cost is Rs. 25/MWh. The incremental fuel costs fro two plants are

,

(IES 96)

29. The incremental cost characteristic of a two plant system are IC1 = 1.0 P1 + 85 Rs/MWhIC2 = 1.0 P2 + 72 Rs/MWh

Where P1 and P2 are in MW. The loss coefficient matrix in MW is given by

Compute the optimal scheduling with λ=150 Rs/MWh. The load on the system is 30 MW. For an improved value of λ with 10% change write the coordination equations. (IES 92)

UNIT – III

1. a. Explain about spinning reserve in hydro power plants.b. Explain about co-ordination in hydro thermal system. (JNTU May 09)

2. Using dynamic programming method, how do you find the most economical combination of the units to meet a particular load demand? (JNTU May 09)

3. Write the advantages of operation of hydro thermal combinations. (JNTU May 09)

4. Determine the daily water used by hydro plant and daily operating cost of thermal plant with the load connected for total 24 hrs from the given data. The load connected, PD = 400MWGeneration of thermal plant, PGT = 200MWGeneration of hydro plant, PGH = 300MW. (JNTU May 09)

5. Discuss optimal power flow procedures with its inequality constraints, and how to handle dependent variables with penalty function. (JNTU May 09)

6. Discuss the Dynamic programming method to solve Unit commitment problem in power systems.(JNTU May 09)

7. Explain: long range hydro scheduling, deriving necessary expressions. (JNTU May 09)

8. Derive the co-ordination equation for the optimal scheduling of hydro-thermal interconnected power plants. (JNTU May 09)

9. Explain the problem of scheduling hydro - thermal power plants. What are the constraints in the problem? (JNTU May 09)

10. Define the cost function of power flow problem with control variables and explain a method to obtain the solution. (JNTU Nov 08)

11. Write short notes on:a. Equations of Load flow. B. Solving of Load flow equations. (JNTU Nov 08)

12. Define the lagrangian function for optimization of power flow solution with controlled variables and using the gradient method obtain the solution. (JNTU Nov 08)

13. Explain the problem of scheduling hydro - thermal power plants. What are the constraints in the problem? (JNTU Feb 08)

14. Derive the co-ordination equation for the optimal scheduling of hydro-thermal interconnected power plants. (JNTU Feb 08)

15. Discuss the costs associated with hydro plants. (JNTU Nov 07)

16. Write short notes on:i. Equations of Load flow.

ii. Solving of Load flow equations. (JNTU Feb 07, Nov 07, 05)

17. Develop load flow equation suitable for solutions by Gauss Seidel method using Nodal admittance approach (JNTU Feb 07, Nov 07, 06, 02)

18. Explain: long range hydro scheduling, deriving necessary expressions. (JNTU Feb 07, Nov 06)

19. State what is meant by base-load and peak-load stations. Discuss the combined hydro electric and steam station operation. (JNTU Mar 06, Nov 05, 03)

20. Explain in detail the short term hydro thermal scheduling. (JNTU Nov 04, 02)

21. Develop load flow equation suitable for solutions by Newton-Raphson method using nodal admittance approach. (JNTU Nov 02)

22. Explain Hydro-thermal scheduling problem. (JNTU Nov 02)

23. Describe optimal scheduling of Hydro thermal system without considering losses.(JNTU Nov 02)

24. Differentiate between long range hydro scheduling and short range hydro scheduling.

25. Write in detail about economic co-ordination of power generation among hydro and thermal plants.

26. Discuss the optional power flow problem formulation and discuss their solution by successive LP methods

27. A hydro electric station has to operate with a mean head of 50 m. It makes use of water collected over a catchment area of 200 km2 over which the average annual rainfall is 420 cm with a 30% loss due to evaporation. Assuming the turbine efficiency as 85% and the alternator efficiency as 80% calculate the average power that can be generated. (IES 93)

28. Explain long range and short range Hydro-scheduling problems.

29. Explain hydro electric plant models with diagrams.

30. Derive the condition for best efficiency in hydro thermal system using langrangian method.31. A hydro plant and a steam plant are to supply a constant load of 80 MW for 1 MWK (168h). The unit

characteristics are Hydro plant: q = 250 + 10PH acre-ft/h

0 < PH < 90 MW Steam plant: Hs = 50 + 11PS + 0.02 PS2

11.25 < PS < 45 MW Solve for TS* ,the run time of steam plant.

32. Explain the Dynamic-programming solution to the hydrothermal scheduling problem.

33. Reformulate the optimal hydro thermal scheduling problem considering the inequality constraints on the thermal generation and water storage employing penalty functions. Find out the necessary equations and gradient vector to solve the problem.

34. If there are three unitsUnit 1 : Min = 150 MW

Max = 600 MWH1 = 510 + 7.2 P1 + 0.00142 P12 MBtu/h

Unit 2 : Min = 100 MWMax = 400 MWH2 = 310 + 7.85 P2 + 0.00194 P22 MBtu/h

Unit 3 : Min = 50 MWMax = 200 MWH3 = 78 + 7.97 P3 + 0.00482 P32 MBtu/h

Fuel Cost 1 = 1.1 R/MbtuFuel Cost 2 = 1.0 R/MBtuFuel Cost 3 = 1.2 R/MbtuConstruct a priority list for the units.

35. Explain the significance of patton’s Security function. Explain the Security constrained unit commitment and startup considerations.

36. Find the optional generation schedule for a typical day, where in load varies in threes steps of 8 hours each as 8MW, 12MW and 6MW respectively. There is no water inflow into the reservoir of the hydro plant. The initial water storage in the reservoir is 120 m3/s and final water storage is 80 m3/s. Basic head is 35m, e = 0.0075, Reservoir is rectangular. Non effective water discharge be assumed as 3 m3/s. IFC of thermal plant is (1.5 PGT + 36) Rs/Hr. Transmission losses neglected.

37. Determine the most economical units to be committed for a load of 9 MW. Let the load changes be in steps of 1 MWUnit No. Capacity (MW) Cost Curve Parameters (d=0)

Min Max a(Rs/MW2) b(Rs/MW)1 1 12 0.776 23.52 1 12 1.67 26.53 1 12 2.60 30.04 1 12 2.50 32.0

UNIT – IV

1. Two generating stations A and B of capacities 20MW and 10MW and speed regulation of 2% and 3% respectively. Two stations are connected through are inter connector and motor generator set. The set is connected to bus bar of A and has a capacity of 3 MW and full load slip of 4%. Determine the load of the inter connector when there is load of 8MW on bus bar B due to its own consumers but A has no external load. (JNTU May 09)

2. Briefly explain swing equation with simplified diagram. (JNTU May 09)

3. A 80 MVA synchronous generator operates on full load at a frequency of 50Hz. The load is suddenly reduced to 40 MW. Due to time lag in the governor system, the steam valve begins to close after 0.3 secs. Determine the change in frequency that occurs in this time. H=4 KW -/KVA of generator capacity.

(JNTU May 09)

4. a. Explain the necessity of maintaining a constant frequency in power system operation.b. Two generators rated 200 MW and 400 MW are operating in parallel. The droop characteristics of

their governors are 4% and 5% respectively from no load to full load. Assuming that the generators are operating at 50 Hz at no load, how would a load of 600 Mw be shared between them? What will be the system frequency at this load? Assume free governor operation. Repeat the problem if both the governors have a droop of 4% (JNTU May 09)

5. Obtain the power flow solution without inequality constraints by minimizing the appropriate cost function. (JNTU May 09)

6. Making suitable assumptions, derive the T.F. of syn generator and the steam turbineset.(JNTU Nov 08)

7. a. Derive the model of a speed governing system and represent it by a block diagram.b. A 100 MVAsynchronous generator operates on full load at a frequency of 50 Hz. The load is suddenly

reduced to 50 MW. Due to time lag in the governor system, the steam valve begins to close after 0.4 secs. Determine the change in frequency that occurs in this time. H=5 KW-s/KVA of generator capacity. (JNTU Nov 08)

8. a. Explain the necessity of maintaining a constant frequency in power system operation.

b. Two generators rated 200 MW and 400 MW are operating in parallel. The droop characteristics of their governors are 4% and 5% respectively from no load to full load. Assuming that the generators are operating at 50 Hz at no load, how would a load of 600 Mw be shared between them? What will be the system frequency at this load? Assume free governor operation. Repeat the problem if both the governors have a droop of 4%. (JNTU Nov 08)

9. With a neat diagram, explain briefly different parts of a turbine speed governing system.(JNTU Feb 07, Nov 02)

10. i. Derive the model of a speed governing system and represent it by a block diagram. ii. A 100 Mva synchronous generator operates on full load at a frequency of 50 Hz. The load is suddenly

reduced to 50 MW. Due to time lag in the governor system, the steam valve begins to close after 0.4 secs. Determine the change in frequency that occurs in this time. Given H=5 Kw-s/Kva of generator capacity. (JNTU Feb 07, Mar 06, Nov 06, 05, 04, 03, 02, IES 95)

11. Derive the generator load model and represent it by a block diagram. (JNTU Mar 06)

12. i. Describe the various blocks of IEEE Type-1 excitation system and develop the mathematical model of the system. (JNTU Apr 05, 04, 03 Nov 03)

ii. Explain IEEE type-1 model of an excitation system and hence derive the transfer function.(JNTU Aug, Apr 06, Jan 05, 03, 01, Mar, Dec 02)

13. i. Explain about the various performance requirements of excitation system.ii. Explain the elements of an excitation system. (JNTU Apr 06)

14. Explain the turbine model and represent as a block diagram and obtain transfer function of the models.(JNTU Apr 06, 04, Jan 03, Dec 02)

15. i. Explain the turbine speed governing mechanism and hence derive the transfer function of speed governing system. (JNTU Apr 06, 05, 03, Nov 03)

ii. Explain what is meant by Cross-coupling between control loops.

16. Explain the characteristics of an excitation system and develop a transfer function of first order for the same. (JNTU Aug 06, Apr 06, 05, 04, 03, Nov 03, Dec 02, Jan 03, 02, 01)

17. What is an exciter ? Why it is necessary for Synchronous Generator? (JNTU Apr 06, 05)

18. Explain the turbine model and hence discuss transfer functions of reheat and non-reheat models. (JNTU Apr 05, 03, Nov 03)

19. With the help of a neat sketch, explain operation of various components of a fly ball speed Governor system. (JNTU Apr 04)

20. Explain the mathematical model of a Generation-load model and hence derive the transfer function.(JNTU Apr 04)

21. i. Derive the small signal transfer function of Generator–Governor model. Explain various time constants in it and their significance.

ii. How a steam turbine can be modeled using an approximate linear model. (JNTU Apr 04)

22. Derive the transfer function of speed-governing mechanism and hence derive the transfer function.(JNTU Apr 04)

23. Explain the functions of an excitation and develop the block diagram for voltage regulator scheme. Develop the transfer function model of each block. (JNTU Apr 04, 03, Nov 03)

24. What are all the feed back control systems that are provided for a synchronous Generator? Explain their importance and how they are independent from each other. (JNTU Nov 03)

25. i. Explain the necessity of speed-governing system, develop the mathematical model and derive the transfer function. (JNTU Apr 04)

ii. Draw the block diagram of the excitation system and hence develop the transfer function.(JNTU Mar 02, Dec 02)

26. Clearly explain how a synchronous generator is modeled for steady state analysis. Draw the phasor diagram and obtain the power angle equation for a non salient pole synchronous generator connected to an infinite bus. Sketch the power angle curve. (JNTU Mar 02, Apr 03)

27. Explain the steady-state modelling of a synchronous machine. (JNTU Mar 02, Dec 02)

28. A 2-pole 50 Hz, 11 KV turbo alternator has a ratio of 100 MW, pf 0.85 lagging. The rotor has a moment of inertia of 10,000 kgm2.Calculate H and M. (JNTU Dec 04)

29. Explain any two types of excitation systems of a generator with relevant diagrams. State the requirements of a good excitation systems.

30. Three generators are feeding a load of 100 MW. The details of the generators are Rating(MW) Efficiency (%) Regulation(p.u.) on 100 MVA baseGenerator- 1 100 20Generator-2 100 30Generator-3 100 40In the event of increased load power demand, which of the following will happen?

a. All the generators will share equal powerb. Generator-3 will share more power compared to Generator-1c. Generator-1 will share more power compared to Generator-2d. Generator-2 will share more power compared to Generator-3 (GATE 09)

31. A lossless power system has to serve a load of 250 MW. There are two generators (G1 and G2) in the system with cost curves C1 and C2 respectively defined as follows:

C1 (PG1) = PG1 + 0.055 x PG12

C2 (PG2) = 3PG2 + 0.03 x PG22

Where PG1 and PG2 are the MW injections from generator G1 and G2 respectively. Then the minimum cost dispatch will be a. PG1 = 250 MW; PG2 = 0 MW b. PG1 = 150 MW; PG2 = 100 MWc. PG1 = 100 MW; PG2 = 150 MW d. PG1 = 0 MW; PG2 = 250 MW (GATE 09)

32. For 800 MJ stored energy in the rotor at synchronous speed, what is the inertia constant H for a 50 Hz, four pole turbo-generator rated 100 MVA, 11 kV? (IES 05)a. 2.0 MJ/MVA b. 4.0 MJ/MVA c. 6.0 MJ/MVA d. 8.0 MJ/MVA

33. Two 200 MVA alternators operate in parallel. The frequency drops in the first machine from 50 Hz at no load to 48 Hz at full load, whereas in case of the other machine, the frequency drops from 50 Hz to 47 Hz under the same conditions :

i. How the two machines will share a total load of 300 MW ?ii. Determine the maximum load at unity power factor which can be delivered by the two machines

without overloading any of them. (IES 03)

34. An alternator with negligible damping is connected to an infinite bus. Write down its swing equation in usual form. How inertia constant H is defined here ? (IES 00)

35. Describe swing equation for i. Multi machine system; ii. for machines swinging coherently.

36. Describe the swing equation for non coherent machines.

37. Given KE= 1.0, VR Max= 8.0; SE Max= 0.9; SE 0.75 Max= 0.50 (all in p.u.), find Ax and Bx.

38. Using exciter model with VR= Vrcs= 0.05, find KE self so that Efd = 1.0 when Ax = 0.1 and Bx = 0.6 (all pu)

39. The generator is driven by hydro turbine and is delivering a constant power load. The governor input is

determined from differential equation . The permanent speed droop is deglected

in modelling the governor. For the system to be stable shown that , where ,

40. A generator equipped with static excitation system is on no load. The system is initially is steady state with EFD = VT = 1.0. Obtain the response of EFD for a step increase in Vref by 0.3 p.u. for two cases. T1do= 4S; ii. T1do= 1.5S.Excitation system data: KA = 300; T = 0.0285; TB = 15S; EFD Max = 5.0, EFD Min = -5.0; TF= 1.5S

i. KF = 0.0; TC = 1S (NO TGR)ii. KF = .0.0; TC = 1S (no ESS only TGR)iii. KF = 0.03; TC = 10S (NO TGR, only ESS)iv. KF = 0.03, TC = 1S (TGR and ESS are included)

41. Using IEE type-1 exciter model with KE= 1.0 SE= 0 and TE= 0.5 Sec, compute response of Efd for a constant input of VR= 1.0. Use initial value of Efd= 0 (all pu). (T3-Ch4)

42. Two generating stations A and B have full load capacities of 500 MW and 210 MW respectively. The inter-connector connecting the two stations has a motor-generator set (plant C) near station A of full load capacity 50 MW. Percentage changes of speeds of A, B and C are 5, 4 and 2.5 respectively. The loads on bus bars A and B are 250 MW and 100 MW respectively. Determine the load taken by Set C and indicate the direction in which the energy is flowing.

UNIT – V

1. Discuss in detail the dynamic response of load frequency control of an isolated power system with a neat block diagram. (JNTU May 09)

2. Explain the dynamic response in load frequency control of an isolated power system under controlled case. (JNTU May 09)

3. a. Explain the concept of “control area” in the load frequency control of a power system.b. Show how the steady state error of frequency in a typical load frequency control of a power system is

reduced to zero. (JNTU May 09)

4. a. Obtain the dynamic response of load frequency control of isolated power system for first order approximation.

b. Obtain the dynamic response of load frequency controller with and without integral control action.(JNTU May 09)

5. a. Write notes oni. Control area concept. ii. Area control error. (JNTU May 09)

b. Explain proportional plus integral control for load frequency control for a single area system.

6. Define area control error “ACE” in a power system. Discuss how the “proportional plus Integral” control system is implemented to minimize the “Integral of ACE with time” for a step load disturbance.

(JNTU Nov 08)

7. The following data is available for an isolated area, capacity 4000MW, frequency 50Hz, operating load 2500MW, speed regulation constant 2HZ/pu MW. Inertia constant = 5secs. 2% of change in load takes place for 1% change in frequency. Find

a. Largest change in step load if steady state frequency is not to exceed by more than 0.2Hzb. Change in frequency as a function of time after a step change in load. Derive the formula used.

(JNTU Nov 08)

8. A control area has a total rated capacity of 10,000MW. The regulation R for all the units in the area in 2Hz/pu MW. A 1% change in frequency causes a 1% change in load. If the system operates at half of the rated capacity and the load increases by 2% (JNTU Nov 08)

a. Find the static frequency drop b. If the speed governor loop were open, what would be the frequency drop. Derive the formula used.

9. The following data is available for an isolated area, capacity 4000MW, frequency 50Hz, operating load

2500MW, speed regulation constant 2HZ/pu MW. Inertia constant = 5secs. 2% of change in load takes place for 1% change in frequency. Find

i. Largest change in step load if steady state frequency is not to exceed by more than 0.2Hzii. Change in frequency as a function of time after a step change in load. Derive the formula used.

(JNTU Feb 08)

10. Obtain the dynamic response of load frequency control of isolated power system for first order approximation. (JNTU Feb 08)

11. i. What are the disadvantages in a power system if the frequency is not maintained constant.ii. Explain how the variation of load effects the frequency of a power system. (JNTU Feb 08, 07)

12. A control area has a total rated capacity of 10,000MW. The regulation R for all the units in the area in 2Hz/pu MW. A 1% change in frequency causes a 1% change in load. If the system operates at half of the rated capacity and the load increases by 2%

i. Find the static frequency dropii. If the speed governor loop were open, what would be the frequency drop.

Derive the formula used. (JNTU Feb 08, Nov 06)

13. Explain the necessity of maintaining a constant frequency in power system operation.

Write notes on i. control area concept. ii. area control error(JNTU Feb 08, 07, Mar 06, Nov 06, 05, 03)

14. Two generators rated 200 MW and 400 MW are operating in parallel. The droop characteristics of their governors are 4% and 5% respectively from no load to full load. Assuming that the generators are operating at 50 Hz at no load, how would a load of 600 Mw be shared between them? What will be the system frequency at this load? Assume free governor operation. Repeat the problem if both the governors have a droop of 4%. (JNTU Feb 08, 07, Nov 07, 06, 05, 03, Mar 06)

15. Show how the steady state error of frequency in a typical load frequency control of a power system is reduced to zero. (JNTU Nov, Feb 07, Mar 06)

16. Draw the block diagram representation of load frequency control. (JNTU Nov 07)

18. Two generators rated 200 MW and 400 MW are operating in parallel. The droop characteristics of their governors are 4% and 5% respectively from no load to full load. The speed changers are so set that the generators operate at 50 Hz sharing the full load of 600 MW in the ratio of their ratings. If the load reduces to 400 MW, how will it be shared among the generators and what will be the system frequency? Assume free governor operation. (JNTU Feb 07, Nov 03, 02)

19. i. Develop the mathematical model of hydraulic value actuator in load frequency control problems.ii. Two generators rated 200Mw and 400Mw are operating in parallel. The droop characteristics of their

governors are 4% and 6% respectively from no-load to full-load. Assuming that the generator are operating at 50Hz, how a load of 500Mw be shared between them.

(JNTU Aug, Apr 06, 03, Nov 03)

20. Two generators are supplying power to a system. Their ratings are 50 and 500Mw respectively. The frequency is 50Hz and each generator is half loaded. The system load is increased by 110Mw and as a result frequency drops to 49.5Hz. What must be the individual regulations if two generators should increase their turbine powers in properties to their ratings? Also express the regulation in p.u.Hz and p.u.Mw. (JNTU Apr 06, 03)

21. Give a complete block diagram representation of Load-frequency control of an isolated power system? Explain various time constants in the block diagram? (JNTU Apr 05, 04, 03)

22. With first order approximation explain the dynamic response of an isolated area for load frequency control. (JNTU Nov 05, 04, 02, Mar 06, Apr 05)

23. Draw the schematic diagram showing the speed changer setting, governor and steam admission valve and indicate how steam input is regulated with the change in load. Derive the T.F. of the above system.

(JNTU Nov 06, 05)

24. Explain the functions of various blocks of automatic load frequency control problems (JNTU Apr 05, 03, Nov 03)

25. i. With a neat block diagram explain the load frequency control for a single area system.

ii. Two generators rated 250 MW and 500 MW are operating in parallel. The droop characteristics are 4% and 6% respectively. Assuming that the generators are operating at 50 Hz at no load, how would a load of 750 MW be shared. What is the system frequency? Assume free governor action.

(JNTU Nov 04, 03, 02)

26. With a neat block diagram explain the steady state analysis of an isolated power system.(JNTU Nov 04, 02)

27. What is load frequency problem? Briefly explain the various frequency control strategies used to regulate the power system frequency. (JNTU Nov 04)

28. Two generators rated 300 MW and 400 MW are operating in parallel. The droop characteristics of their governors are 4% and 6% respectively from no load to full load. The speed changers of the governors are set so that a load of 400 MW is shared among the generators at 50 Hz in the ratio of their ratings. What are the no load frequencies of the generators. (JNTU Nov 04, 02)

29. Why we need to maintain frequency and voltage of power system at rated values? If not, explain the consequences? (JNTU Nov 03)

30. Two generators rated 200 MW and 400 MW are operating in parallel. The droop characteristics of their governors are 4% and 5% respectively from no load to full load. The speed changers are so set that the generators operate at 50 Hz sharing the load of 600 MW in the ratio of their ratings. If the load reduces to 400 MW, how will it be shared among the generators and what will the system frequency be? Assume free governor operation. The speed changers of the governors are reset so that the load of 400 MW is shared among the generators fat 50 Hz in the ratio of their ratings. What are the no load frequencies of the generators? (JNTU Nov 02)

31. i. Discuss in detail the importance of load frequency problem.ii. With a neat diagram explain the process of speed Governing System. (JNTU Nov 02)

32. The power system has two synchronous generators. The Governor-turbine characteristics corresponding to the generators are P1 = 50 (50 - f), P2 = 100(51 -f)Where f denotes the system frequency in Hz, and P1 and P2 are, respectively, the power outputs (in MW) of turbines 1 and 2. Assuming the generators and transmission network to be lossless, the system frequency for a total load of 400 MW is i. 47.5 Hz ii. 48.0 Hz iii. 48.5 Hz iv. 49.0 Hz (GATE 01)

33. For a synchronous generator connected to an infinite bus through a transmission line, how are the change of voltage (∆V) and the change of frequency (∆f) related to the active power (P) and the relative power (Q)?i. ∆V is proportional to P and ∆f to Q ii. ∆V proportional to Q and ∆f to Piii. Both ∆V and ∆f are proportional to P iv. Both ∆V and ∆f are proportional to Q

(IES 07)

34. Two generators rated 200 MW and 400 MW having governor droop characteristics of 4% and 5% respectively are operating in parallel. If the generators operate on no load at 50 Hz, the frequency at which they would operate with a total load of 600 MW is

i. 48.5 Hz ii. 47.69 Hz iii. 46.82 Hz iv. 49.04 Hz (IES 02)

35. The speed regulation parameter R of a control area is 0.025 Hz/Mw and the load frequency constant D is 2 Mw/Hz. The area frequency response characteristics (AFRC) is ____i. 42.0 MW/Hz ii. 40 MW/Hz iii. 20 MW/Hz ii. 2 MW/Hz (IES 01)

36. Two alternators each having 4% speed regulation are working in parallel. Alternator ‘1’ is rated for 12 MW and alternator ‘2’ is rated for 8 MW. When the total load is 10 MW, the loads shared by alternators 1 and 2 would be respectively.i. 4 MW and 6 MW ii. 6 MW and 4 MW iii. 5 MW and 5 MW iv. 10 MW and zero (IES 00)

37. Two generators rated at 200 MW and 400 MW are operating in parallel. Both the governors have a drop of 4%, when the total load is 300 MW. They share the load as (suffix ‘1’ is used for generator 200 MW and suffix ‘2’ is used for generator 400 MW)i. P1 = 100 MW and P2 = 200 MW ii. P1 = 150 MW and P2 = 150 MWiii. P1 = 200 MW and P2 = 100 MW iv. P1 = 200 MW and P2 = 400 MW (IES 99)

38. The combined frequency regulation of machines in area of capacity 1500 MW and operation at a nominal frequency of 60 kHz is 0.1 pu on its own base capacity. The regulation in Hz/MW will bei. 0.1/1500 ii. 60/1500 iii. 6/1500 iv. 60/150 (IES 97)

39. Two synchronous generators are supplying a common load. Generator 1 has a no load frequency of 51.5 Hz and regulation of 1 MW/Hz. The total load 2.5 MW at .8 pf logging.

i. At what frequency, are the generators supplying this load and how much power is supplied by each generator?

ii. An additional load of 1 MW is attached to this system. What will be the new frequency and power generation of each alternator?

iii. How much is governor set point of generator set point of generator 2 to be adjusted to bring the system frequency at 50Hz for 3.5 MW system load? (IES 97)

40. The following data pertain to two alternators working in parallel and supplying a total load of 80 MW:Machine 1: 40 MVA with 5% speed regulationMachine 2: 60 MVA with 5% speed regulation. The load sharing between machines 1 and 2 will be: (IES 97)

i. ii. 40 MW 40 MW iii. 30 MW 50 MW iv. 32 MW 48 MW

41. Two 200 MvA alternators operated in parallel. The frequency drops in the first machine from 50Hz at no load to 48 Hz at full load. Where as in case of the other machine, the frequency drops from 50 Hz to 47Hz under the same conditions

i. How the two machines will share a load of 300 Mwii. Determine the maximum load at unity power factor which can be delivered by the two machines

without overloading any of them (IES 96)

42. A 100 MvA synchronous generator operates on full load of a frequency of 50Hz. The load is suddenly reduced to 50Mw. Due to time lag in governor system, the steam value begins to close after 0.4 seconds. Determine the change in frequency that occurs in this time. Given H = 5 Kw - S/ KvA of generator capacity. (IES 95)

43. The following two synchronous machines are operating in parallel.Machine A 50 MW 6% speed regulationMachine B 50 MW 3% speed regulation

i. Determine the load taken by each machine for a total load of 80 MW when the speed changers are set to give rated speed at 100% rated output.

ii. The speed changers of machine A is so adjusted that 80MW is equally shared. Find the output of machine. A for rated speed and also its percentage speed at no load. (IES 92)

44. Two generators rated at 170MW and 250MW are operating in parallel. The governor settings on the machines are such that they have 4 and 3 percent droops. Determine

i. Load taken by each machine for a total load of 200 MWii. The percentage adjustment in no load speed to be made by the speeder motor if the machines are to

share the load equally.

45. A 210 MVA, 50Hz turbo alternator operates at no load at 3000 rpm. A load of 75 MW is suddenly applied to the machine and steam valves to the turbine commence to open after 1 sec due to time lag in governor system. Assuming inertia constant H of 5 KW-Sec per KVA of generator capacity, calculate the frequency to which the generated voltage drops before the steam flow commences to increase to meet the new load.

46. Two generating stations A and B are of capacities 20 MW and 10 MW and speed regulation 2% and 3% respectively. The two stations are connected through an inter connector and a motor generator set. The set is connected to bus bars of A and has a capacity of 3 MW and full load slip of 4% Determine the load on the inter connector when there is a load of 8 MW on B bus bars due to its own consumer but A has no external load.

47. In the expression for ∆YE(S) assume at t=0 and increment ∆PC = 1.0 is applied. Assume the speed governor is on test, operating open loop, so that as an independent input, we may assume that ∆F(S) = 0 Find the increment in the steam value opening ∆YE(t) and sketch response.

48. A standard figure for R is 0.05 P.U. This relates fractional changes in frequency to fractional changes in ∆Pt(S). Thus we have ∆w/∆w0= -0.05 ∆Pt, where ∆Pt in per unit.

i. Suppose that the frequency changes from 50 Hz to 49 Hz. Find increase in Pt.ii. What change in frequency would cause the Pt to charge from 0 to 1.

49. A turbine generator set is operating open loop. The turbine output is 500MW at 3600 rpm system parameters are R = 0.01 rad/MW-sec, Tsg = 0.001 Sec and Tt = 0.1 Sec. Suppose now the output increase to 600 MW. Find now the turbine speed.

50. A 300 MVA synchronous generator operates on full load of a frequency of 50 Hz. The load is suddenly reduced to 38 MW. Due to time lag in the governor system the steam valve begins to close after 0.8 sec. Determine the change in frequency that occurs in this time. Given H = 6 KW-S/KVA of generator capacity.

51. Two generators 2000 MW and 400 MW are operating in parallel. The droop characteristics of their governors are 4% and 5% respectively from no load to full load. The speed changers are so set that the generators operate at 50 Hz sharing the load of 600 MW in the ratio of their ratings. If the load reduces

to 400 MW. How will it be shared among the generators and what will the system frequency be ? changers of governors are reset so that the load of 400 MW shared among the generators for 50 Hz in the ratio of their ratings. What are the no load frequencies of the generators.

52. Two generators rated 400 MW and 800 MW are operating in parallel. The droop characteristics of their governors are 6% and 7% respectively from no load to full load. Assuming that the generators are operating at 50 Hz at no load, how would a load of 950 MW be shared between them ? What will be the system frequency at this load ? Assume free governor operation. Repeat the problem if both the governors have a droop characteristics of 7%.

53. Two generators rated at 120MW and 250MW are operating in parallel. The governor settings on the machines are such that they have 4 and 3 percent droops.Determine i) the load taken by each machine for a total load of 200 MW, ii) the percentage adjustment in the no load speed to be made by the speeder motor if the machines are to share the load quality.

54. A 210 MVA, 50Hz turbo alternator operates at no load at 3000 rpm. A load of 75 MW is suddenly applied to the machine and steam values to the turbine commence to open after 1 Sec due to time lag in governor system. Assuming inertia constant H of 5 KW-Sec per KVA of generator capacity, calculate the frequency to which the generated voltage drops before the steam flow commences to increase to meet the new load.

55. Two generating stations A and B are of capacities 20 MW and 10 MW and speed regulation 2% and 3% respectively. The two stations are connected through an inter connector and a motor generator set. The set is connected to bus bars of A and has a capacity of 3 MW and full load slip of 4% Determine the load on the inter connector when there is a load of 8 MW on B bus bars due to its own consumer but A has no external load.

UNIT – VI

1. a. What is area control error? What are the control strategies?b. For two-area load frequency control with gain blocks, derive an expression for steady values of change

in frequency and tie line power for simultaneously applied unit step load disturbance inputs in the two areas. (JNTU May 09)

2. a. Explain the operation of two generating stations connected by a tie line. b. Two generating stations A & B have full load capacities of 500 MW and 210 MW respectively. The

inter connector connecting the two stations has a motor-generator set (Plant ‘C’) near station A of full load capacity of 50 MW. Percentage changes of speed of A, B and C are 5, 4 and 2.5 respectively. The loads on bus bars A and B are 250 MW and 100 MW respectively. Determine the load taken by set C and indicate the direction in which the energy is flowing. (JNTU May 09)

3. a. Explain load frequency control problem in a Multi-area power system.b. Derive an expression for steady-state change of frequency and tie-line power transfer of a two-area

power system. (JNTU May 09)

4. Give a typical block diagram for a two-area system inter connected by a tie line and explain each block. Also deduce relations to determine the frequency of oscillations of tie line power and static frequency drop. List out assumptions made. (JNTU May 09, Nov 08)

5. a. What is load frequency control problem in 2-area power system? Why is it essential to maintain constant frequency in an inter-connected power system?

b. Explain the power frequency characteristics of an inter-connected power system?(JNTU Nov 08)

6. Draw the block diagram for two-area load frequency control with integral controller blocks, and explain each block. (JNTU Nov 08)

7. i. Explain load frequency control problem in a Multi-area power system.ii. Derive an expression for steady-state change of frequency and tie-line power transfer of a two-area

power system. (JNTU Feb 08, Feb 07, Nov 06, 05)

8. Draw the block diagram for two-area load frequency control with integral controller blocks, and explain each block. (JNTU Feb 08)

9. Give a typical block diagram for a two-area system inter connected by a tie line and explain each block. Also deduce relations to determine the frequency of oscillations of tie line power and static frequency drop. List out assumptions made. (JNTU Feb 08, 07, Mar 06, Nov 07, 06, 05, 04, 02)

10. Explain the operation of two generating stations connected by a tie line. (JNTU Feb 08, Nov 03)

11. Two generating stations A and B have full load capacities of 500 MW and 210 MW respectively. The inter connector connecting the two stations has a motor-generator set (Plant ‘C’) near station A of full load capacity of 50 MW. Percentage changes of speed of A, B and C are 5, 4 and 2.5 respectively. The loads on bus bars A and B are 250 MW and 100 MW respectively. Determine the load taken by set C and indicate the direction in which the energy is flowing. (JNTU Feb 08, Nov 03)

12. Two power stations A and B each have regulation of 0.1 p u and stiffness K of 1.0 p. u. The capacity of system A is 1350 MW of B 1150 MW. The two systems are interconnected through a tie line and are initially at 60 Hz. If there is 100 MW load change in system A, calculate the change in the steady-state values of frequency and power transfer P12 with the participation of governor control.

(JNTU Nov 07, 04)

13. For two-area load frequency control with integral controller blocks, derive an expression for steady values of change in frequency and tie line power for simultaneously applied unit step load disturbance inputs in the two areas. (JNTU Nov 07)

14. Two power stations A B are inter connected by tie line and an increase in load of 250 MW on system B causes a power transfer of 150 MW from A to B. When the tie line is open the frequencies of system A is 50 c/s and of system B is 49.5c/s. Determine the values of KA and KB which are the power frequency constants of each generator. (JNTU Nov 07, 06)

15. What is load frequency control problem? Why is it essential to maintain constant frequency in an inter-connected power system? (JNTU Nov 07, 06, 05, 04)

16. For two-area load frequency control with gain blocks, derive an expression for steady values of change in frequency and tie line power for simultaneously applied unit step load disturbance inputs in the two areas. (JNTU Nov 06, Mar 06)

17. Explain the power frequency characteristics of an inter-connected power system?(JNTU Nov 05)

18. What is area control error? What are the control strategies? (JNTU Mar 06)

19. Two power systems A and B are inter connected by a tie line and have power frequency constants KA and KB per Hz. An increase in load of 500 MW on system ‘A’ causes a power transfer of 300 MW from ‘B’ to ‘A’. When the tie line is opened the frequency of system ‘A’ is 49 HZ and of system ‘B’ 50 Hz. Determine the values of KA and KB, deriving any formulae used. (JNTU Apr 05, Nov 03)

20. Two power stations A and B are inter connected by tie line and an increase in load of 250 MW on system B causes a power transfer of 100 MW from A to B. When the tie line is open the frequencies of system a is 60 c/s and of system B is 59.5 c/s. Determine the values of KA and KB which are the power frequency constants of each generator. (JNTU Nov 04)

21. Two power stations A and B each have regulation (R) of 0.1 p u (on respective capacity bases) and stiffness K of 1.0 p. u. The capacity of system A is 1500 MW and of B 1000 MW. The two systems are interconnected through a tie line and are initially at 60 Hz. If there is 100 MW load change in system A, calculate the change in the steady-state values of frequency and power transfer P12 (with and without the participation of governor control). (JNTU Nov 03)

22. Explain tie line bias control of two-area power system. (JNTU Nov 02)

23. For two-area frequency control employing integral of area control error, obtain an expression for steady values of change in frequency for unit step disturbance in one of the areas. Assume both areas to be identical, comment upon the stability of the system for parameter values given below:Tsg = 0.4s; Tt = 0.5s; Tps = 20s; Kps = 100; R= 3; Ki=1; b = 0.425; a12 =1; 2 T12 = 0.05.

(JNTU Nov 02)

24. Discuss the importance of optimal two area load frequency control with suitable analysis(JNTU Nov 02)

25. With a neat composite block diagram of 2-area load frequency control, explain how the tie line power and frequencies are changing. (JNTU Nov 02)

26. What is meant by load frequency control of two area system? (JNTU Nov 02)

27. Develop mathematical modeling of load frequency control of two area system. (JNTU Nov 02)

28. Explain the linear mathematical model of 2-area power system.

29. Draw a block diagram to represent a two area system showing all necessary details and explain the various blocks.

30. Which of the following are the advantages of interconnected operation of power systems?i. Less reserve capacity requirement.ii. More reliability.iii. High power factor.iv. Reduction in short-circuit level.Select the correct answer using the codes given below:Codes:i. 1 and 2 ii. 2 and 3 iii. 3 and 4 iv. 1 and 4 (IES 98)

31. Consider a power system with two plants S1 and S2 connected through a tie line as shown in figure.

When the load frequency control of the system is considered, the ‘Flat tie-line control’ system is preferred over the ‘Flat frequency regulation system’, because

i. It is advantageous to control the frequency from any one particular plant without disturbing the other one during load-swings on either S1 or S2 areas

ii. This ensures that only the more efficient plant’s input is controlled for load variation in any areaiii. Only the tie line is required to absorb the load-swingsiv. The load-change in a particular area is taken acare of by the generator in that area. (IES 97)

32. The synchronizing coefficient between two areas of a 2-area power system is (symbols have usual meanings).

i. ii. iii. iv. (IES 95)

33. A power system consists of 2 areas (Area 1 and Area 2) connected by a single tieline. It is required to carry out a loadflow study on this system. While entering the network data, the tie-line data (connectivity and parameters) is inadvertently left out. If the loadflow program is run with this incomplete data

i. The load flow will converge only if the slack bus is specified in Area 1ii. The load flow will converge only if the slack bus is specified in Area 2iii. The load flow will converge if the slack bus is specified in either Area 1 or Area 2iv. The load flow will not coverage if only one slack bus is specified. (GATE 02)

34. Two power systems A and B each having a regulation (R) of 0.05 p.u of their respectively capacity bases and a stiffness (damping coefficient) of 0.75 p.u are connected through a tie line, initially carrying no power. The capacity of the system A is 2000 MW and that of system B is 3000 MW. It there is an increase in load of 200 MW in system A, What is the change in the steady state and power transfer. (GATE 97)

35. Explain the tie line power participation in load frequency and Q-V regulators.

36. An inter connector with inductive reactance of 25 Ohms and negligible resistance has two units of generations with voltages of 33 KV and 30 KV at its ends. A load of 6 MW is to transferred form 33 KV to 30 KV side of inter connector. Determine the power factor of the power transmitted and other necessary conditions when between two ends.

37. For two-area frequency control employing integral of area control error, obtain an expression for steady values of change in frequency for unit step disturbance in one of the areas. Assume both areas to be identical, comment upon the stability of the system for parameter value’s given below. The time constants of speed governor turbine and power system are 0.4, 0.5, 20 secs respectively, Power system gain constant = 100; Regulation =3 ; Ki=1; b=0.425, a12 = 1; 2 π T12=0.05.

38. Consider two turbine generator units connected by a tie line operating in the steady state. Suppose that ∆PD1 = a1 u(t) and ∆PD2 = a2 u(t) where u(t) is unit step function. Calculate and compare the steady state change in frequency in two cases.i. T12 = 0, ii. T12 > 0

39. For two area system

PAGO = PADO = 1000 MWPBGO = PBDO = 10,000MWRA = 0.015 rad/Sec/MWRB = 0.0015 rad/Sec/MWBy the above values the scheduled tie line flow between the two areas is 0 MW. A sudden change of load of 10 MW occurs in area A. Determine ACE in each area, the change in frequency, and the appropriate control signals that will be provided to the supplementary control.

40. For R = 0.01 PU for area 1, 0.002 PU for area 2, D = 0.8 PU for area 1, 1.0 for area 2. Base MVA = 500 for area 1, 500 for area 2. A load change of 100MW (0.2 PU) occurs in area1. What is the new steady state frequency and what change in tie line flow? Assume both areas were at nominal frequency 50 Hz to begin?

41. Suppose that the generating unit 2 in two area control has a very large moment of inertia. Approximate it by a infinite bus i.e. ∆f2 = 0) and show that the block diagram for generating unit 1 reduces to the same form as the block diagram in single area control.

42. For R and D values of area 1, 0.01 PU and 0.8 PU, and of area 2, 0.02 PU and 1 PU resolve for the 100 MW load change in area 1 under the following conditions.Area 1 : Base MVA = 2000 MVAArea 2 : Base MVA = 500 MVASolve for load change of 100 MW occurring in area 2 with R values and D values mentioned above and base MVA for each area is 500 MVA.

43. A 2-GW control area (1) is inter connected with a 10-GW area (2). The 2-GW area has system parameters R = 2.4 Hz/PU MW, Pr = 2000 MW, D = 8.33 x 10-3 PU MW/Hz normal operating load = 1000 MW. Area 2 has same parameters, but in terms of the 10-GW base. A 20-MW load increase takes place in area 1. Find static frequency drop and tie line power change.

44. A two area system connected by a tie line has the following parameters on a 100 MVA base. Area 1 2Speed regulation R1=0.05R2= 0.0625Frequency-sens load co-efficient D1=0.6 D2= 0.9Inertia constant H1=5 H2= 4Base power 1000 MVA 1000 MVAGoverner time constant Tg1=0.2 sec Tg2=0.3 secTurbine time constant TT1=0.5 sec TT2=0.6 secThe units are operating in parallel at the nominal frequency of 60 Hz. The synchronizing power co-efficient is computed from the initial operating conditions and is given to be PS=2 per unit. A load

change of 187.5 MW occurs in area 1. Determine the new steady state frequency and the change in tie-line flow.

45. Two power systems A and B are inter connected by a tie line and have power frequency constants KA and KB per Hz. An increase in load of 600 MW on system ‘A’ causes a power transfer of 285 MW from ‘B’ to ‘A’. When the tie line is opened the frequency of system ‘A’ is 48 Hz and of system ‘B’ 50 Hz. Determine the values of KA and KB deriving any formula used.

46. Two power stations A and B each have regulation (R) of 0.2 Pu (on respective capacity bases) and stiffness K of 1.0 P.u. The capacity of system A is 1456 MW and of B is 958 MW. The two systems are interconnected through a tie line and are initially at 50 Hz. If there is 120 MW load change in system A, Calculate the change in the steady state values of frequency and power transfer P12 (with and without the participation of governor control).

UNIT – VII

1. Explain proportional plus integral control for load frequency control for a single area system.(JNTU Feb 08, 07, Mar 06, Nov 06, 05, 03)

2. Obtain the dynamic response of load frequency controller with and without integral control action. (JNTU Feb 08, Mar 06, Nov 06, 05, 02)

3. Draw the block diagram of a power system showing the governor, turbine and syn. generator, indicating their transfer functions. For a step disturbance of ΔPD, obtain the response of “increment in frequency”, making suitable assumptions.

i. Without proportional plus integral controller, andii. With proportional plus integral control. (JNTU Feb 08, Nov 07, 06, 05, Mar 06)

4. Discuss the merits of proportional plus integral load frequency control of a system with a neat block diagram. (JNTU Nov 04, 02)

5. Discuss the importance of combined load frequency control and economic dispatch control with a neat block diagram. (JNTU Nov 04)

6. Load frequency control uses (IES 99)i. proportional controllers alone ii. integral controllers aloneiii. both proportional and integral controllers iv. either proportional or integral controllers

7. Load frequency control is achieved by properly matching the individual machines’si. reactive powers ii. generated voltages iii. turbine inputsiv. turbine and generator ratings (IES 98)

8. In the load-frequency control system with free governor action, the increase in load-demand under steady conditions is met

i. only by increased generation due to opening of steam valveii. only by decrease of load-demand due to drop in system frequency iii. partly by increased generation and partly by decrease of load-demandiv. partly by increased generation and partly by increased generator excitation. (IES 96)

9. In the single area control system we have following data Tp=10 Sec., Tg=Tt=0, Kp=100Hz/pu Mw, D = 3hz/pumw, PD = 0.1 pu Mw, Ki = 0.1. Compute the time error caused by a step disturbance of magnitude given above. Prove in particular that the error is reduced by increasing the given Ki. Express the error in seconds and cycle if the system frequency is 50Hz.

10. Find the expression for dynamic response of change in frequency for a step change in load for the single area control system with integral control under assumptions that Tg 0, Tt 0 and damping constant B 0. Also find the response when the system is uncontrolled.

11. For an isolated power system with following data Pr = 100 Mw, PD0 = 50Mw, H = 5.0 sec., R = 2.5 Hz/Pv MW. If load would increase 1 per unit for 1 per best frequency increase, find the static frequency change for the controlled case when the load is increased by 10 Mw. Estimate the critical magnitude of integral controller gain.

12. A single area system has the following data area capacity = 4000 Mw, operating load frequency f = 50Hz, H = 5 sec., D = 2.5% and % change in load for 1%. Change in frequency find

i. Frequency response and static frequency error in the absence of secondary loop (integral control) it a step increase of 80Mw, in load occurs.

ii. Find critical value of Ki of integral controller is used.13. The time constant of the governing systems of steam turbine is 0.2 seconds. While that of turbine is 2

seconds. H = 5 sec., D = 4% (Hz/Pv Mw). Load changes by 1% for 1% change in frequency. The rated capacity is 1500 Mw and f = 50Hz. Find static frequency error for step change in load. If integrated controller is used.

14. Discuss the merits of proportional plus integral load frequwency control of system with neat block diagram.

15. Discuss the importance of combined load frequency control and economic dispatch control with a neat block diagram.

16. A 210MVA 50 Hy urbo alternator operates at no load at 3000 r.p.m. A load of 75 MW is suddenly applie to the machine and the steam valves to the turbine commence to open after 1 sec due to the time lag in the governor system. Assuming interial constant H are 5KW-sec per kVA of generator capacity. Calculate the frequency to which the generated voltage drops before the steam flow commences to increase to meet the new load.

17. Explain what do you understand by control area and control area error.

18. Find the primary ALFC loop parameters for a control area having the following data : Control area capacity = 10000 MWNormal operating load = 5000 MWInertia constant H = 5 secondsRegulation D = 3 Hz / pa MWAssume that load frequency dependency is linear and 1% change in frequency corresponds to 1% change in load.

19. The following data is available for an isolated area. Capacity 4000MW, frequency 50Hz. operating load 2500 MW. Speed regulation constant 2 HZ/Pu. MW inertia constant H=5 seconds 2% change is

lead for 1% change is frequency. Find (a) largest change instep load if steady state frequency is not change by more than 0.2 HZ (b) change is frequency as a function of time after a step change in load.

20. A single area system has the following data; area capacity = 4000 MW operating load frequency f = 50Hz, H = 5 seconds, D = 2.5% & 1% change in load for 1% change in frequency. Find (a) frequency response and static frequency error in the absence of secondary loop (integral control) if a step increase of 80MW is load occurs (b) critical Ki of integral controller is used.

21. The time constant of the governing systems of steam turbine is 0.2 seconds while that of turbine is 2 seconds. H = 5 seconds D = 4% (Hz/Pu.MW) load changes by 1% for 1% change in frequency. The rated capacity is 1500 MW and f=5 Hy (a) Find an equation expressing ∆F (s) is term of step change ∆PD is load and various system parameter. (b) find largest step change in load if frequency is not to change by more than 1% in steady state and integral controller is not used (c) static frequency error for this Step change in load if integral controller is used.

22. Two generating stations A and B have full load capacities of 200 MW and 75 MW respectively. The inter connector connecting the two stations has an induction motor / synchronous generation (plant C) of full load capacity 25 MW. Percentage changes of speeds of A, B and C are 5, 4 and 3 respectively. The loads on bus bars A and B are 75MW and 30 MW respectively. Determine the load taken by the set C and indicate the direction in which the energy is flowing.

23. Find the sttic frequency drop if the load is suddenly increased by 25 MW on a system the following data. Rated capacity Pr=500 MWOperating Caapcity PD=250 MWInertia constant H=5 secGovernor regulation D=2Hz/PUMWFrequency f=50HzAlso find the additional generation.

UNIT – VIII

7. a. Explain about the losses that occur due to VAR flow in power systems.b. Explain how the generators act as VAR sources in a power network. (JNTU May 09)

8. What is load compensation? Discuss its objectives in power system. (JNTU May 09)


8. A three-phase induction motor delivers 500 hp at an efficiency of 0.91, the operating power factor being 0.76 lagging. A loaded synchronous motor with a power consumption of 100 KW is connected in parallel with the induction motor. Calculate the necessary kVA and the operating power factor of the synchronous motor if the overall power factor is to be unity. (JNTU May 09)

7. Two substations are connected by two lines in parallel with negligible impedance, but each containing a tap-charging transformer of reactance 0.18 p.u. on the basis of its rating of 200 MVA. Find the net absorption of reactive power when the transformer, taps are set to 1:1.1 and 1:0.9 respectively. Assume p.u., voltages to be equal at the two ends and at sub-station. (JNTU May 09)

8. Explain reason for variations of voltages in power systems and explain any one method to improve voltage profile. (JNTU May 09)

7. a. With a neat phasor diagrams explain the reactive power balance and its eect on system voltage.b. The load at the receiving end of a three-phase, over-head line is 25 MW, power factor 0.8 lagging, at a

line voltage of 33 kV. A synchronous compensator is situated at the receiving end and the voltage at both ends of the line is maintained at 23 kV. Calculate the MVAr of the compensator. The line has resistance 5 ohm per phase and inductive reactance 20 ohm per phase. (JNTU May 09)

8. What is load compensation? Discuss its objectives in power system. (JNTU May 09)

7. a. Discuss in detail about the generation and absorption of reactive power in power system components.b. A load of (15 +j10) MVA is supplied with power from the busbars of a power plant via a three phase

110 kV line, 100 km lagging. The transmission line is represented by -model and has the following parameters. R= 26.4 ohms, X = 33.9 ohms, B = 219 × 10-9 mho Voltage across the power plant bus bars V1 = 116 kV. Find the power consumed from the power plant bus bars. (JNTU May 09)

8. What is a static compensator? Explain with diagrams working principle of various types of static compensators. (JNTU May 09)


8. What is load compensation? Discuss its objectives in power system. (JNTU Nov 08)

7. a. Write short notes on compensated and uncompensated transmission linesb. Explain briefly about the shunt and series compensation of transmission systems.

8. A three(S)phase transmission line has resistance and inductive reactance of 25 and 90 respectively. With no load at the receiving end a synchronous compensator there takes a current lagging by 900, the voltage at the sending end is 145 kV and 132 kV at the receiving end. Calculate the value of the current taken by the compensator. When the load at the receiving end is 50 MW, it is found that the line can operate with unchanged voltages at sending and receiving ends, provided that the compensator takes the same current as before but now leading by 900. Calculate the reactive power of the load.

(JNTU Nov 08)7. (a) Write short notes on compensated and uncompensated transmission lines(b) Explain briefly about the shunt and series compensation of transmission sys-tems. [8+8]8. Explain clearly what do you mean by compensation of line and discuss brieflydi_erent methods of compensation. Nov 08

7. (a) Explain about the losses that occur due to VAR flow in power systems.(b) Explain how the generators act as VAR sources in a power network.8. What is a static compensator? Explain with diagrams working principle of varioustypes of static compensators. Nov 08

1. A 11 KV supply busbar is connected to an 11/132 kV, 100 MVA, 10 per cent reactance, transformer. The transformer feeds a 132 kV transmission link consisting of an overhead line of impedance (0.014 + j0.04) p.u. and a cable of impedance (0.03 + j0.01) p.u. in parallel. If the receiving end is to be maintained at 132 kV when delivering 80 MW. 0.9 p.f. lagging calculate the power and reactive power carried by the cable and the line. All p.u. values relate to 100 MVA and 132 kV bases.

(JNTU Feb 08)

2. What is load compensation? Discuss its objectives in power system. (JNTU Feb 07, Nov 07, 06)

3. i. Explain about the losses occurred due to VAR flow in power systems. ii. Explain how the generators are acted as VAR sources in a power network.

(JNTU Feb 08, 07, Mar 06, Apr 05, Nov 07, 06, 05, 04)

4. Explain clearly what do you mean by compensation of line and discuss briefly different methods of compensation. (JNTU Feb 08, 07, Nov 07, 06, 04, 03)

5. A three-phase induction motor delivers 500 hp at an efficiency of 0.91, the operating power factor being 0.76 lagging. A loaded synchronous motor with a power consumption of 100 KW is connected in parallel with the induction motor. Calculate the necessary KVA and the operating power factor of the synchronous motor if the overall power factor is to be unity. (JNTU Feb 08, Mar 06, Nov 05, 04)

6. What is a static compensator ? Explain with diagrams working principle of various types of static compensators. (JNTU Feb 08, Nov 03, 04)

7. i. Discuss in detail about the generation and absorption of reactive power system components.ii. A load of (15 + j10) MVA is supplied with power from the busbars of a power plant via a three phase

110 KV line, 100 km lagging. The transmission line is represented by p-model and has the following parameters.R=26.4 ohms, X = 33.9 ohms, B = 219 x 10-9 ohm. Voltage across the power plant bus bars V1 = 116 kV. Find the power consumed from the power plant bus bars. (JNTU Nov 07, 03, 02)

8. Find the rating of synchronous compensator connected to the tertiary winding of a 132 KV star connected, 33 KV star connected, 11 KV delta connected three winding transformer to supply a load of 66 MW at 0.8 power factor lagging at 33 KV across the secondary. Equivalent primary and tertiary winding reactances are 32 ohm and 0.16 ohm respectively while the secondary winding reactance is negligible. Assume that the primary side voltage is essentially constant at 132 KV and maximum of nominal setting between transformer primary and secondary is 1:1.1. (JNTU Nov 07, 06, 03)

9. A three-phase transmission line has resistance and inductive reactance of 25 and 90 respectively. With no load at the receiving end a synchronous compensator there takes a current lagging by 900, the voltage at the sending end is 145 kV and 132 kV at the receiving end. Calculate the value of the current taken by the compensator. When the load at the receiving end is 50 MW, it is found that the line can operate with unchanged voltages at sending and receiving ends, provided that the compensator takes the same current as before but now leading by 900. Calculate the reactive power of the load.

(JNTU Nov 07, 05)

10. A three phase transmission line has resistance and inductive reactance (line to neutral) of 25 ohms and 85 ohms. With no load at the receiving end but with a synchronous compensator there taking a current lagging by 900, the voltage at the sending end is 145 KV and 132 KV at the receiving end. Calculate the value of the current taken by the compensator. When the load at the receiving end is 50 MW, it is found that the line can operate with unchanged voltages at sending and receiving ends, provided that the compensator takes the same current as before but now leading by 900. Calculate the power factor of the load. (JNTU Feb 07, Nov 04)

11. i. Write short notes on compensated and uncompensated transmission lines.ii. Explain briefly about the shunt and series compensation of transmission systems.

(Feb 07, Mar 06, Nov 05, Nov 04)12. Explain reason for variations of voltages in power systems and explain any one method to improve

voltage profile. (JNTU Feb 07, Nov 04, 03)

13. With a neat phasor diagrams explain the reactive power balance and its effect on system voltage.(JNTU Nov

06)

14. i. With a neat phasor diagrams explain the reactive power balance and its effect on system voltage.ii. The load at the receiving end of a three-phase, over-head line is 25 MW, power factor 0.8 lagging, at a

line voltage of 33 kV. A synchronous compensator is situated at the receiving end and the voltage at both ends of the line is maintained at 23 kV. Calculate the MVAr of the compensator. The line has resistance 5 ohm per phase and inductive reactance 20 ohm per phase. (JNTU Nov, Mar 06)

15. A load of (66+j60) MVA at the receiving end is being transmitted via a single circuit 220 KV line, having resistance of 21 ohms and reactance of 34 ohms. The sending end voltage is maintained at 220 KV. The operating conditions of power consumers require that at this load voltage drop across the line should not exceed 5 percent. In order to reduce voltage drop, standard single phase, 66 KV, 40 KVAR capacitors are to be switched in series in each phase of the line. Determine the required number of capacitors, rated voltage and installed capacitors of the capacitor tank. The losses in the line are neglected. (JNTU Mar 06, Nov 03)

16. i. What does on mean by load compensation? (JNTU Mar 06, Nov 04)ii. With neat diagrams discuss shunt and series compensation. (JNTU Apr 05)iii. What are the specifications of load compensator? (JNTU Mar 06, Nov 02)

17. i. Describe the effect of thyristor-controlled static shunt compensators to meet reactive power requirement in the power systems.

ii. Compare the technical advantages of static compensator over synchronous condenser. (JNTU Nov

05)

18. Describe the necessity of connecting synchronous compensators and shunt capacitors in a power system. (JNTU Nov 04)

19. Two substations are connected by two lines in parallel of negligible impedance, each containing a transformer of reactance 0.18 p.u and rated at 120 MVA. Calculate the net absorption of reactive power when the transformer taps are set to 1:1.15 and 1:0.85 respectively i.e. tap changer is used. The p.u. voltages are equal at the two ends and are constant in magnitude. (JNTU Nov 04)

20. Two substations are connected by two lines in parallel with negligible impedance, but each containing a tap-charging transformer of reactance 0.18 p.u. on the basis of its rating of 200 MVA. Find the net absorption of reactive power when the transformer, taps are set to 1:1.1 and 1:0.9 respectively. Assume p.u., voltages to be equal at the two ends and at sub-station. (JNTU Nov 04)

21. i. Describe the effect of connecting shunt reactors connected in high voltage transmission system.ii. Describe the features of saturated reactor compensator with its V/I characteristics.(JNTU Nov 04)

22. A long transmission line has the constants A=0.97 1Ð20, B=84Ð750 find the additional reactive power requirement at the receiving end to meet a load of 63 MW at 0.8 p.f. lagging, when both the sending end and receiving and voltages are to be maintained at 132 kV. (JNTU Nov 04)

23. Explain the operations of synchronous condenser and mention its applications in power systems and derive the expression for capacity of the synchronous condenser. (JNTU Nov 04)

24. i. Explain how transformers are used to control the flow of real and reactive power in the power system network.

ii. Explain the combined use of Tap-changing transformers and reactive power injection in a power system. (JNTU Mar 06, Nov 05)

25. A 400 KV line is fed through an 132/400 KV transformer from a constant 132 KV supply. At the load end of the line the voltage is reduced by another transformer of normal ratio 400/132 KV. The total impedance of line and transformers at 400 KV is (50 + j100) ohm. Both transformers are equipped with tap-changing facilities which are so arranged that the product of the two off-nominal setting is unity. If the load on the system is 250 MW at 0.8 p.f. lagging, calculate the settings of the tap-changers required to maintain the voltage of the load bus bar at 132 KV. (JNTU Nov 03)

26. Explain with diagrams, the operations of a fixed capacitor and thyristors controlled reactor.(JNTU Nov

03)

27. i. Describe the effect of connecting series capacitors in the transmission system.ii. A single circuit three-phase 220 KV line runs at no load. Voltage at the receiving end of the line is 210

KV. Find the sending end voltage, if the line has resistance of 20.5 ohms, reactance of 81.3 ohms and the total susceptance as 5.45 x 10-4 mho. The transmission line is to be represented by p-model.

(JNTU Nov 02)

28. Discuss the advantages and disadvantages of different types of compensating equipment for transmission systems. (JNTU Nov 02)

29. Discuss the effect of compensation on the maximum power transfer in a transmission line. (JNTU Nov

04)

30. What is static VAR compensator? Where it is used? Also state merits of static VAR compensator over other methods of voltage control (JNTU Apr 05)

31. A 3-phase 50 Hz transmission line has the following constants A=0.99Ð1620, B=50Ð73.70 find the MVAR rating on no load and full load of a synchronising phase modifier to maintain a sending and receiving voltages at 70 KV. and 66 KV respectively, when the line is delivering a load of 24 MVA, 0.8 pf lag

32. A shunt reactor of 100 MVAr is operated at 98% of its rated voltage and at 96% of its rated frequency. The reactive power absorbed by the reactor is;i. 98 MVAr ii. 104.02 MVAr iii. 96.04 MVAr iv. 100.04 MVAr

(GATE 98)

33. A factory draws 100 kW at 0.7 p.f laggging from a 3-phase, 11 kV supply. It is desired to raise the p.f. to 0.95 lagging using series capacitors. Calculate the rating of the capcitor required. (GATE 97)

34. In a 400 kV network, 350 kV is recorded at a 400 kV bus .The reactive power absorbed by a shunt rated for 50 MVAR ,400 kV connected at the bus is (GATE 94)i. 61.73 MVAR ii. 55.56 MVAR iii.45 MVAR iv. 40.5 MVAR

35. The power factor of an industrial 3 phase load of 490 KW is to be improved from 0.7 lagging to 0.97 lagging by connecting loss free delta connected capacitors across 6.6 KV, 50 Hz supply. The cost of suitable capacitors and control gear is Rs.200 per KVAR and annual tariff charge is 120 Rs. Per KVA maximum demand. The annual interest and depreciation charges are 15 per cent calculate.

i. The total KVAR rating of capacitors required. ii. The required value of capacitance per phaseiii. The net annual saving (GATE 92)

36. The combined effect of series and shunt compensation on transmission lines in terms of degree of series compensation (Kse), degree of shunt compensations (Ksh), and surge impedance of uncompensated line (Z0) is given by which one of the following equations?

i. ii.

iii. iv. (IES 04)

37. A three phase inductive compensator (TCR) has an inductance of L Henry per phase and negligible resistance. It is controlled by a pair of anti-parallel SCRs in each phase. The triggering angle is varied to get the required compensation. The supply voltage is V volts per phase. Derive the expressions for the rms voltage and corresponding rms current per phase of the compensator.

(IES 99)

38. To improve the power factor in three-phase circuits, the capacitor bank is connected in delta to make i. capacitance calculation easy ii. capacitance value smalliii. the connection elegant iv. the power factor correction more effective

(IES 99)

39. Describe the drawbacks of the thyristor controlled reactor (TCR) used for VAR control. (IES 98)

40. Comment on the statement “It is not possible to achieve simultaneously both unity pf and Zero voltage regulation”.

41. Discuss the problem associated with charging long uncompensated line and suggest the method to overcome this problem.

42. A radial long uncompensated line with constant sending end voltage is terminated through a synchronous load. Derive an expression for maximum power transfer when termination is through a variable resistance. Hence discuss the voltage instability problem.

43. Discuss the effect of series and shunt compensation of lines on the surge impedance loading of the lines. If shunt compensation is 100%, what happens to SIL and voltage profile.

7. SUBJECT DETAILS

7.2 NON-CONVENTIONAL SOURCES OF ENERGY


7.2.2 Scope

7.2.3 Prerequisites

7.2.4 Syllabus

i. JNTU

ii. GATE

iii. IES


7.2.6 Websites


7.2.8 Journals


7.2.10 Session Plan




i. JNTU

ii. GATE

iii. IES

7.5.1 OBJECTIVE AND RELEVANCE:

In a span of time situated about one hundred to one hundred and fifty years ago, people would have completed their daily routine work without moving more than ten kilometers from where they lived. The reason is obvious as the daily needs like cooking, lighting, eating, heating, etc. were largely met from resources within this radius. In today’s era of information technology, the earth has been reduced to a global village where people from one remote corner exchange necessary information with friends, relatives, business partner situated several thousand kilometers across the globe. In fact, the three great challenges facing mankind in the new millennium are preservation of peace, eradication of poverty and conversation of our environment. Undoubtedly, each of the aforesaid goals is intertwined with questions of sources of energy, their demand and supply, access and harnessing.

Truly the measure of development in any society in these days is synonymous with quantum of energy consumption. This is why energy has been recognized as a critical input parameter for national development. Modern day energy demands are still met largely from fossil fuels like coal, oil and natural gas. Besides coal, natural gas, electricity from hydro and nuclear energy are considered to be commercial energy sources.

It is a fact that most developing countries are passing through the initial stages of industrialization. Naturally, their energy consumption is growing at a greater rate in comparison to the developed countries. During 1990-2000, conventional energy consumption of the Asia Pacific countries has increased by 32.5 percent compared with 11 percent growth of the world consumption. In spite of the higher rate of growth of energy consumption, the present per capita energy consumption in the developing countries is much lower in comparison to the developed countries. It is also a fact that the energy input to the economy of developing countries is still at a very low level and a large section of the increasing population in many of these countries does not have access to commercial energy and electricity. It is also expected that their demand for energy will continue to grow at high rates for a number of decades to come. Therefore, a priority of developing countries is to ensure that supply of energy does not become a constraint to their economic growth.

7.5.2 SCOPE

This subject enables students to find alternative energies with different technology for small and medium power consumers. This also helps in knowing the future energies for man kind. Enables in setting up energy centers for community based dual-fuel generating plants.

7.5.3 PREREQUISITES

The knowledge of electrical energy and its applications are very much essential. The electric power generation with various sources like Hydel, Thermal, Nuclear plants operations and principles are required.

7.5.4.1 JNTU SYLLABUS

UNIT – I OBJECTIVETo learn about role and potential of new and renewable sources, and also about sun, solar radiation condition and instruments used for measuring solar radiation.

SYLLABUS

PRINCIPLES OF SOLAR RADIATION : Role and potential of new and renewable source, the solar energy option, Environmental impact of solar power, physics of the sun, the solar constant, extraterrestrial and terrestrial solar radiation, solar radiation on titled surface, instruments for measuring solar radiation and sun shine, solar radiation data.

UNIT – II OBJECTIVE

In this unit students can learn the different types of solar energy collectors.

SYLLABUS

SOLAR ENERGY COLLECTION: Flat plate and concentrating collectors, classification of concentrating collectors, orientation and thermal analysis, advanced collectors.

UNIT – III OBJECTIVE

To know about different solar energy storage devices and its applications.

SYLLABUS

SOLAR ENERGY STORAGE AND APPLICATIONS : Different methods, Sensible, latent heat and stratified storage, solar ponds. Solar Applications- solar heating/cooling technique, solar distillation and drying, photovoltaic energy conversion

UNIT – IV OBJECTIVE

To know about sources and potential of wind energy, different wind mills and their characteristics.

SYLLABUS

WIND ENERGY : Sources and potentials, horizontal and vertical axis windmills, performance characteristics, Betz criteria.

UNIT – V OBJECTIVE

To know about principles of bio-conversions with different methods and economic aspects.

SYLLABUS

BIO-MASS : Principles of Bio-Conversion, Anaerobic/aerobic digestion, types of Bio-gas digesters, gas yield, combustion characteristics of bio-gas, utilization for cooking, I.C. Engine operation and economic aspects.

UNIT – VI OBJECTIVE

To know about resources, different types of geothermal wells and harnessing of geothermal energy.

SYLLABUS

GEOTHERMAL ENERGY : Resources, types of wells, methods of harnessing the energy, potential in India.

UNIT – VII OBJECTIVE

To know about different principles of converting OTEC, tidal and wave energy conversion.

SYLLABUS

OCEAN ENERGY : OTEC, Principles utilization, setting of OTEC plants, thermodynamic cycles. Tidal and wave energy: Potential and conversion techniques, mini-hydel power plants, and their economics.

UNIT – VIII OBJECTIVE

To know about different types of thermal energy conversions and their applications. And also fuel cells, principles of paradise loss in thermodynamic aspects.

SYLLABUSDIRECT ENERGY CONVERSION: Need for DEC, Carnot cycle, limitations, principles of DEC. Thermo-electric generators, seebeck, peltier and joul Thomson effects, Figure of merit, materials, applications, MHD generators, principles, dissociation and ionization, hall effect, magnetic flux, MHD accelerator, MHD Engine, power generation systems, electron gas dynamic conversion, economic aspects. Fuel cells, principles, faraday’s law’s, thermodynamic aspects, selection of fuels and operating conditions.

7.5.4.ii SYLLABUS - GATE

Not applicable.

7.5.4.iii SYLLABUS – IES

Not applicable.


TEXT BOOKS

T1 Renewable energy resources/ Tiwari and Ghosal/ Narosa.T2 Non-Conventional Energy Sources /G.D. Rai

REFERENCE BOOKS

R1 Renewable Energy Sources /Twidell & WeirR2 Solar Energy /SukhameR3 Splar Power Engineering / B.S Magal Frank Kreith & J.F Kreith.R4 Principles of Solar Energy / Frank Krieth & John F Kreider.R5 Non-Conventional Energy / Ashok V Desai /Wiley Eastern.R6 Non-Conventional Energy Systems / K Mittal /WheelerR7 Renewable Energy Technologies /Ramesh & Kumar /NarosaR8 Non-Conventional Energy Resources / B H Khan - TMHR9 Renewable Energy Systems / D Mukhergee & S Chakrabarti - New Age Int.R10 Non-Conventional Energy Resources / D S Chauhan & S K Srivastava - New Age Int.

7.5.6 WEBSITES

1. www.ieee.org2. www.solarenergy.com3. www.photovoltagsystem.com4. www.worldenergy.org5. www.energy.ca.gov6. www.waterpower.hypermart.net7. energy.sourceguidw.com8. www.renewableenergy/com9. www.renewablenergyaccess.com/rea10. www.iredaltd.com11. www.homepower.com



Designation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering


2. Name : Prof..D.M.Vinod KumarDesignation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering

NIT-Warangal – 506004.Phone number : +91-870-2431616(O)e-mail : dvmk @nitw.ac.in

3. Name : Dr. Bhagwan K.MurthyDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering


4. Name : V.T. SomashekharDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : Department of Electrical and Electronics Engineering

NIT-Warangal – 506004.Phone number : +91-870-2453416 (O) e-mail : [email protected], [email protected]

5. Name : Dr. A.D.RajkumarDesignation : ProfessorDepartment : Electrical EngineeringOffice Address : Department of Electrical Engineering

University College of EngineeringOsmania University, Hyderabad-500007

Phone number : +91-040-27682382 (O)e-mail : [email protected]

6. Name : Dr. M. VijayakumarDesignation : Associate ProfessorDepartment : Electrical EngineeringOffice Address : Department of Electrical Engineering

JNTU College of Engineering, Ananthapur, A.Pe-mail : www.jntu.ac.in

7. Name : Prof. Shankarram

Designation : ProfessorDepartment : Department of Electrical EngineeringOffice Address : JNTU College of Engineering, Kukatpally, Hyderabade-mail : www.jntu.ac.in

NATIONAL


Dy. Director (Administration.), IIT - Delhi, Hauzkhas, New Delhi - 110016.Phone number : +91-11-26591250 (O) , Fax : 91-11-26862037,e-mail : [email protected], [email protected]

2. Name : Dr. S.V. Kulkarni,Designation : Associate Professor,Department : Electrical and Electronics EngineeringOffice address : IITBombay, Powai, Mumbai - 400076, India,

Phone number : +91- 22-25671098,e-mail : [email protected]


Office Address : Room No. II/211, IIT Delhi Phone number : +91 11 2659 1094 ,91 11 2659 1886

email : [email protected]

4. Name : Dr. Sivaji ChakravortiDesignation : Professor,Department : Electrical and Electronics engineering

Jadavpur University, Kolkatta - 700032, Indiaemail : [email protected], [email protected]

INTERNATIONAL


Department : School of Electrical EngineeringOffice address : Georgia Institute of Technology, USA.Phone NumberE-mail : [email protected]

2. Name : Dr. Clayton R Paul, Designation : ProfessorDepartment : Electrical and Computer Engineering,Office : School of Engineering, Mercer University, Macom,Georgia-31207,Phone Number : (912) 301-2213,Website : www.faculty.mercer.paul_cr


Department : Dept. of Electrical EngineeringOffice address : Ira A.Fulton School of Engineering

Arizona State University. Tempe, AZPhone Number : 85287-7206E-mail : Jushan Zhang @ee.gatech.edu


University of Hongkong, Hongkong.Phone Number :Email : [email protected]

7.5.8 JOURNALS



3. Name of the Journal : IEE Proceedings: Part-C [Generation, Transmission & Distribution]












1. Title : Reactive Power and Voltage Control in Distribution Systems With Limited Switching Operations

Author : Liu, M. B.; Canizares, C. A.; Huang, W. Journal : IEEE Transactions on Power Systems Vol., Year &Page No. : May 2009, volume 24, Issue 2, Page(s): 889-899

2. Title : A Direct Load Control Model for Virtual Power Plant ManagementAuthor : Ruiz, N.; Cobelo, I.; Oyarzabal, J.Journal : IEEE Transactions on Power Systems Vol., Year &Page No. : May 2009, volume 24, Issue 2, Page(s): 959-966

3. Title : Micro combustion - Thermonic power generation: feasibility, design and initial results

Author : Chumbo Zhang, Khali Najafi, Luis P. Bernal, Peter D. Washabaugh

Journal : Proc. The 12th International Conference on Solid State Sensors, Actuators and Micro Systems

Vol., Year &Page No. : June 8-12, 2003

4. Title : “Recent developments of thermo-electric power generatin”Author : Luan Weiling and T.U. ShantungJournal : Chinese Science Bulletin Vol., Year &Page No. : Vol. 49, No. 12, 2004, pp. 1212-1219

5. Title : Construction and Performance Analysis of A Parabolic Trough Concentrator

Author : H.V. KumarJournal : Proc. of 26th NREC-2002, Coimbatore Vol., Year &Page No. : pp. 195-199, Jan. 2003.



6. Title : Interfacing Renewable Energy Sources to the Utility Grid Using a Three-Level Inverter

Author : Alepuz, S.; Busquets-Monge, S.; Bordonau, J.; Gago, J.; Gonzalez, D.; Balcells, J.

Journal : IEEE Transactions on Industrial Electronics Vol., Year &Page No. : Volume 53, Issue 5, Oct. 2006 Page(s):1504 - 1511

7. Title : Novel Identification Method of Stator Single Phase-to-Ground Fault for Cable-Wound Generators

Author : Yan Gao; Xiangning Lin; Qing Tian; Pei LiuJournal : IEEE Transactions on Energy ConversionVol., Year &Page No. : Volume 23, Issue 2, June 2008 Page(s):349 - 357

7.3.10 SESSION PLAN

Sl. No. Topics in JNTU Syllabus Modules and Sub modules Lecture

No.Suggested Books with

Page Nos. Remarks

UNIT – I – PRINCIPLES OF SOLAR RADIATION (No. of Lectures – 07)

1

Principles of Solar Radiation:Role and potential of new and renewable source

Objectives and Introduction to NCSE Role of new and renewable sources and examplesPotential of new and renewable sources and examples

L1

T2-Ch1 (P:1-44)

2

The solar energy option, Environmental impact of solar power

Solar energy and its importance Solar energy option Advantages and disadvantages of solar power on environments

L2

T2-Ch1 (P:1-44)R2-Ch1R8-Ch1

3

Physics of the sun,The solar constant

Physics of the sun and some important terms and their definitionsSome important derivations related solar constant

L3

T2-Ch1 (P:1-44)

4 Extraterrestrial and terrestrial solar radiation

Extraterrestrial and terrestrial solar radiation L4 T2-Ch2 (P:47-49)

5

Solar radiation on tilted surface

Solar radiation on horizontal surface and derivation L5 T2-Ch2 (P:49-53)

Solar radiation on tilted surface and derivation L6 T2-Ch2 (P:49-53)

6

Instruments for measuring solar radiation and sunshine,Solar radiation data

Different types of instruments for measuring solar radiation Solar radiation data and its important L7

T2-Ch2 (P:66-69)

UNIT – II – SOLAR ENERGY COLLECTION (No. of Lectures – 09)

7

Solar Energy Collection:Flat plate and concentrating collectors

Introduction.Physical principles of the conversion of solar radiation into heat

L8T2-Ch3 (P:73)

Flat plate collectors L9 T2-Ch3 (P:76-86)Transmissivity of cover system L10 T2-Ch3 (P:87-90)Energy balance equation and collector efficiency L11 T2-Ch3 (P:91-93)

Thermal Analysis of flat plate collectors and useful heat gained by the fluid

L12T2-Ch3 (P:94-101)

8

Classification of concentrating collectors

concentratingcollector- Focusing Type L13 T2-Ch3 (P:102-110)

concentratingcollector- Non-Focusing Type L14 T2-Ch3 (P:102-110)

Advantages and disadvantages of concentrating and flat plate type collectors

L15T2-Ch3 (P:111-112)

9Orientation and thermal analysis,Advanced collector

Performance analysis of a CPC collector L16

T2-Ch3 (P:112-120)

UNIT – III – SOLAR ENERGY STORAGE AND APPLICATIONS (No. of Lectures – 08)

10Solar Energy Storage And Applications : Different methods

IntroductionSolar energy storage systems

T2-Ch16 (P:779-780)

11 Sensible, latent heat, andstratified storage

Sensible heat storage L17 T2-Ch16 (P:804-809)Latent heat storage L18 T2-Ch16 (P:810-816)Electrical storage Chemical storage

L19 T2-Ch16 (P:789-793) (P:794-795)



Page Nos. Remarks

12Solar ponds Introduction

Principle of operation Description

L20T2-Ch4 (P:138-145)

13

Solar Applications- solar heating/cooling technique, solar distillation andDrying

Heating and cooling techniques L21 T2-Ch5 (P:151-167)Solar distillation anddrying L22

T2-Ch5 (P:195-207)

14

Photovoltaic energy conversion.

IntroductionSolar cells Principle operation Cell, Modules, Panels and Arrays

L23L24

UNIT – IV – WIND ENERGY (No. of Lectures – 13)

15

Wind Energy : Sources and potentials

IntroductionBasic Principles L25

T2-Ch6 (P:227-261)

Maximum power L26Force on the blades and thrust on turbines L27

Lift and drag L28Numerical examples L29Wind data and energy estimation L30Basic components of WECS L32Classification of WEC systems L33

16Horizontal and vertical axis windmills

Horizontal axis windmills L34 T2-Ch3 (P:262-263)Vertical axis windmills L35 T2-Ch3 (P:263-284)

17Betz criteria Design consideration of horizontal axis

m/c’s L36 T2-Ch3 (P:73-123)

Continued …. L37 T2-Ch3 (P:73-123)18 Performance characteristics Performance characteristics L38 T2-Ch3 (P:112-120)

UNIT – V – BIO-MASS (No. of Lectures – 06)

19 Bio-Mass : Principles of Bio-Conversion,

Photosynthesis process Biofuels L39 T2-Ch7 (P:324-326)

20 Anaerobic/aerobic digestion Biomass conversion technologies L40 T2-Ch7 (P:311-322)

21 Types of Bio-gas digesters, gas yield

Classifications of biogas plants L41 T2-Ch7 (P:337-340)

22 Combustion characteristics of bio-gas

Combustion Characteristics of biogas L42 R1-Ch11, T2-Ch7, R8-Ch8

23 utilization for cooking, I.C. Engine operation

IC Engine operation L43 T2-Ch7 (P:417-418)

24 Economic aspects. Economic aspects. L44 T2-Ch7 (P:385-391)UNIT – VI – GEOTHERMAL ENERGY (No. of Lectures – 04)

25 Geothermal Energy Resources

Introduction Origin and distribution L45 T2-Ch8 (P:439-442)

26 Types of wells Different types of wells L46 T2-Ch8 (P:445-461)

27 Methods of harnessing the energy

Different methods of harnessing the energy L47 T2-Ch8 (P:476-484)

28 Potential in India. Potential in India. L48 T2-Ch8 (P:487-490)UNIT – VII – OCEAN ENERGY (No. of Lectures – 05)

29 Ocean Energy: OTEC, Principles utilization,

Introduction OTEC Principle, construction L49 T2-Ch9 (P:495-497)

30 Setting of OTEC plants, Setting of OTEC plants, L50 T2-Ch9 (P:497-510)31 Thermodynamic cycles. Thermodynamic cycles. L51 T2-Ch9 (P:510-512)32 Tidal and wave energy: Origin and nature L52 T2-Ch9 (P:510-533)



Page Nos. Remarks

Potential and conversion techniques,

Conversion technologies

33 Mini-hydel power plants, and their economics

Mini-hydel power plants, and their economics L53 T2-Ch9 (P:533-537)

UNIT – VIII – DIRECT ENERGY CONVERSION (No. of Lectures – 07)

34Direct Energy Conversion :Need for DEC, Carnot cycle

IntroductionDECCarnot cycle

L54T2-Ch13 (P:698-707)

35 Limitations, Principles of DEC

Advantages and disadvantages of DEC L55 T2-Ch13 (P:709-710)

36

Thermo-electric generators, seebeck, peltier and joul Thomson effects, Figure of merit, materials, applications,

Thermo-electric generators SeebeckPeltier Thomson effectsFigure of meritMaterialsApplications

L56

T2-Ch13 (P:709-722)

37

MHD generators, principles, dissociation and ionization, hall effect, magnetic flux, MHD accelerator,

MHD generatorsPrinciplesDissociation and ionization hall effectMagnetic fluxMHD accelerator

L57

T2-Ch12 (P:661-677)

38

MHD Engine, power generation systems, electron gas dynamic conversion,

MHD Enginepower generation systemselectron gas dynamic conversion L58

T2-Ch12 (P:678-694)

39 Economic aspects. Economic aspects. L59 T2-Ch12 (P:695-696)

40

Fuel cells,Principles, Faraday’s law’s, Thermodynamic aspects, Selection of fuels and operating conditions.

IntroductionPrinciple and lawsTypesSelection of fuels Operating conditions

L60

T2-Ch12 (P:561-590)


1. Title : Response of Speed wind Turbines to frequency disturbancesAuthor : Andreas Sumper Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : February 2009,Volume: 24, Issue: 1

2. Title : Frequency Regulation Contribution through Variable Speed Wind Energy Conversion Systems

Author : Juan Manciel Mauricio Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : February 2009, Volume: 24, Issue: 1

3. Title : Kinetic Energy of Wind Trubine Generators for System Frequency Support

Author : Ping-Kwan Keung Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : February 2009, Volume: 24, Issue: 1

4. Title : Sheduling of Head-Sensitive Cascaded Hydro Systems: A Non Linear Approach

Author : J.P.S. Catalao Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : February 2009, Volume: 24, Issue: 1

5. Title : Worst case Robust Profit in Generation Self scheduling Author : Rabih A JabrJournal : IEEE Transactions on Power SystemsYear, Vol. & page No. : February 2009, Volume: 24, Issue: 1

6. Title : Radial Power Flow Tolerance Analysis by Interval constraint Propagation

Author : Alfredo Vaccaso Journal : IEEE Transactions on Power SystemsYear, Vol. & page No. : February 2009, Volume: 24, Issue: 1








UNIT – I

1. i. What is meant by renewable energy source? Explain in brief these resources with reference to Indian context. (JNTU Nov 08)

ii. What are the different methods to improve the efficiency of electrical motors and drives?

1. i. What are the various renewable sources of energy? Compare solar energy with other forms emphasizing on merits and demerits.

ii. Explain different methods to improve the power factor in electrical applications. (JNTU Nov 08)

1. i. Briefly explain the following: (JNTU Nov 08)i. Energy Planning. ii. Energy Efficiency.

ii. Explain what are energy efficient electric motors. How do they differ from conventional motors?

1. i. Bring out the importance of solar energy in comparison to other types of renewable energy resources.ii. What are pie charts? Explain their significance in energy audit with a suitable example.

(JNTU Nov 08)

1. i. Explain in detail different kinds of renewable energy resources.ii. Discuss the availability, prospects and economic feasibility of each.iii. Elaborate on the comprehensive approaches to Energy Management. (JNTU Feb 08)

3. i. What are ultimate energy sources? (JNTU Feb 08)ii. Discuss the factors, which affect the efficiency of electrical systems. How can they be improved?

4. Define the terms: (JNTU Feb 08)

i. Solar Altitude angle ii. Beam angleiii. Zenith angle iv. Solar azimuth angle

5. i. Briefly explain the following: (JNTU Feb 08, Nov 07, 02)a. Energy Planning b. Energy Efficiency

ii. Explain what are energy efficient electric motors. How do they differ from conventional motors?

6. Calculate the angle made by beam radiation with the normal to a flat collector on December 1 at 9.00AM, solar time for a location at 28035’ N. The collection is tilted at an angle of latitude plus 100, with the horizontal and is pointing due south. (JNTU Feb 08)

7. i. Bring out the importance of solar energy in comparison to other types of renewable energy resources.ii. What re pie charts? Explain their significance in energy audit with a suitable example.

(JNTU Feb 08)

8. i. List out the reasons for variation in solar radiation reaching the earth than received at the outside of the atmosphere.

ii. Define Hour angle and Zenith angle (JNTU Feb 08)iii. Calculate the sunset hour angle and day length at a location latitude of 350N, on February 14.

9. i. What are the prospects of various renewable energy resources in India?ii. Describe the general principles of Energy management with suitable examples.

(JNTU Nov 07, 04, 03)

10. What is pyrheliometer? With neat sketch, explain about the method of measuring solar radiation using Angstrom compensation pyrheliometer. (JNTU Nov 07, 02 May 04)

11. i. Discuss the need for development of renewable energy resources. (JNTU Nov 07, May 03)ii. What do you understand by energy management and what is its role in industry.

12. What is the difference between a pyrheliometer and a pyranometer? Describe the principle of operation of Eppley pyranometer. (JNTU Nov 07, May 03)

13. i. List out Various non -Conventional Sources of energy. (JNTU Nov 07, May 03)ii. Briefly explain the advantages of renewable sources of energy.iii. Explain briefly the causes of low power factor and how it can be corrected?

14. i. Write short notes on the following: (JNTU Nov 07, 03)a. Solar constant b. Local solar time c. Surface azimuth angle.

ii. Determine the local solar time and declination at a location latitude 23°152 N, longitude 77°302 E at 12.30 IST on June 19. Equation of time correction is given from standard table to be = – (12 012 2 ).

15. i. What do you mean by renewable energy sources? (JNTU Nov 04, 02)ii. Explain various sources of energy briefly.

16. i. What are ultimate energy sources? (JNTU Nov 04, 02)ii. What are the differences between renewable and conventional energy sources.

17. Bring out the importance of solar energy in comparison to other types of renewable energy resources.(JNTU May 04)

18. i. What are the differences between renewable and conventional energy sourcesii. List out the consequences of low power factor on electrical appliances. (JNTU May 04)

19. What are the various renewable sources of energy? Compare solar energy with other forms emphasizing on merits and demerits. Explain different methods to improve the power factor in electrical applications. (JNTU May 04, 03)

20. i. Explain the need of paying attention on renewable energy systems in India. ii. Discuss the importance of planning and leading an energy management programme in an organization.

(JNTU Nov, May 03)

21. What is meant by renewable energy source? Explain in brief these resources with reference to Indian context. What are the different methods to improve the efficiency of electrical motors and drives?

(JNTU Nov, May 03)

22. Calculate the angle made by beam radiation with the normal to a flat collector on December 1 at 9.00AM, solar time for a location at 28°352 N. The collection is tilted at an angle of latitude plus 10°, with the horizontal and is pointing due south. (JNTU Nov 03)

23. Write down the equations for estimation of average solar radiation and determine the monthly average daily global radiation on a horizontal surface for June 22, at the latitude of 10°N, if constant “a” and

“b” are given as equal to 0.30 and 0.51 and the ratio (JNTU Nov 03)

24. i. List out the reasons for variation in solar radiation reaching the earth than received at the outside of the atmosphere. (JNTU Nov 03)

ii. Define Hour angle and Zenith angleiii. Calculate the sunset hour angle and day length at a location latitude of 35°N, on Feb. 14.

25. i. List out various non-Conventional Sources of energy (JNTU Nov 02)ii. Briefly explain the advantages of renewable sources of energy

26. Explain clearly the Beam and diffuse radiation. (JNTU Nov 02)

27. Discuss in detail about the following:i. Sunshine recorderii. Solar radiation on tilted surfaces. (JNTU Nov 02)

28. Discuss in detail about solar radiation geometry. (JNTU Nov 02)

29. Explain the various types of non-Conventional Sources of energy

30. What are the prospects of various renewable energy resources in India?

31. Explain the need of paying attention on renewable energy systems in India.

32. Discuss the need for development of renewable energy resources. What do you understand by energy management and what is its role in industry.

33. Explain in detail Energy Efficiency

34. Explain natural energy currents on earth.

35. What do you mean by primary to end use

36. Describe the general principles of Energy management with suitable examples.

37. Mention the merits of renewable sources of energy

38. Discuss the importance of planning and leading an energy management program in an organization.

39. Explain solar radiation scattering.

40. Write the procedure to estimate solar radiation on Horizontal surfaces.

41. Write the procedure to estimate solar radiation on Tilted surfaces.

42. Explain terrestrial and extra terrestrial solar radiation.

43. Explain clearly the Beam and diffuse radiation.

44. Discuss in detail about the following:i. Sunshine recorder ii. Solar radiation on tilted surfaces.

45. Write solar radiation geometry.

UNIT – II

2. Explain the following with sketch: (JNTU Nov 08)i. Flat plate arrays of solar cell modulesii. Solar cell connecting arrangementsiii. Explain with a neat sketch, the operation of a central tower receiver system for power generation.

2. i. Explain clearly the Beam and diffuse radiation. (JNTU Nov 08)ii. Explain the Construction and operation of solar pond for electric power generation with a line diagram.

2. i. List out different models of solar cells.ii. Explain any two models of solar cells in details with diagrams. (JNTU Nov 08)

2. Explain the operation and working of the following with neat sketch.i. Solar module. ii. Cylindrical parabolic concentrator. (JNTU Nov 08)

2. Explain the following with neat sketches:i. Eppley pyranometerii. Sun shine recorder. (JNTU Feb 08)

1. i. Explain working grid connected wind turbine generator with neat sketch.ii. How do you select a suitable electric generator for wind turbine. (JNTU Feb 08)

2. Calculate the angle made by beam radiation with the normal to a flat collector on December 1 at 9.00 A.M., solar time for a location at 28035’N. The collection is tilted at an angle of latitude plus 100, with the horizontal and is pointing due south. (JNTU Feb 08)

2. i. List out the reasons for variation in solar radiation reaching the earth than received at the outside of the atmosphere.

ii. Define Hour angle and Zenith angle. (JNTU Feb 08)iii. Calculate the sunset hour angle and day length at a location latitude of 350N, on February, 14.

1. What are different types of solar energy collectors? Explain any two in detail.(JNTU Nov 07, May 04)

2. Explain in detail about the different approaches of thermal electric conversion system from solar energy (JNTU Nov 04, 02)

3. Write brief notes on the following: (JNTU Nov 04, May 03)i. Central receiver system ii. Solar farms

4. i. With a neat sketch, explain the working of liquid flat plate collector. (JNTU May 04)ii. What are the various losses encountered and explain a method to evaluate these losses.

5. i. What are various types of concentrating collectors? (JNTU May 03)ii. Explain line focusing collectors in detail with a neat diagram

6. Explain point focusing collector with a neat sketch. What are advantages and disadvantages of concentrating collectors? (JNTU May 03)

7. Explain the following : i. Eppley pyranometer ii. Solar radiation data (JNTU Nov 02)

8. Derive the necessary equations for thermal analysis of flat plate collector and useful heat gained by the fluid. (JNTU Nov 02)

9. Explain flat plate collectors in detail with the help of a neat sketch. (JNTU Nov 02)

10. For which type of heating is solar energy best suited?

11. What is the average range of solar radiation received on earth’s surface during a day?

12. What are the main advantages of flat plate solar collector?

13. What is the approximate value of concentration ratio obtained from a CPC collector?

14. Name three collectors requiring one axis sun tracking?

15. What range of temperature a paraboloidal dish collector may attain?

16. With the help of schematic diagram, explain the working of solar water heating?

17. Explain the principle of conversion of solar energy into heat?

18. What are the main components of a flat-plate solar collector, explain the function of each.

19. How solar air collectors are classified? What are the main application of a drier?

20. Enumerate the different types of concentrating types collectors. Describe a collector used in power plant for generation of electrical energy.

21. Why orientation is needed in concentrating types collectors? Describe the different methods of sun tracking.

22. What are the advantages and disadvantages of concentrating collectors over a flat-plate collectors.

23. Derive the necessary equations for thermal analysis of flat plate collector and useful heat gained by the fluid.

24. Explain central receiver system and solar farms.

25. What are various types of concentrating collectors.

UNIT – III

3. i. Distinguish clearly between the following wind turbine Generation (WTG) units.i. Constant speed constant frequency WTG unit. ii. Variable speed constant frequency WTG unit.

ii. Describe the main applications of wind energy, giving neat sketches. (JNTU Nov 08)

3. i. Why a tall tower is essential for mounting a horizontal axis wind turbine?ii. Why should be a rotor of Darrieus type be located at a height?iii. A wind turbine has rotor diameter of 15m. The wind speed is 7m/s. Assume normal temperature and

air pressure. Energy utilization factor is 0.7. Efficiency of WTG unit is 35%. Calculate the electrical power delivered. (JNTU Nov 08)

1. In a wind turbine, the cambered aerofoil blades are subjected to a wind velocity of 10m/s. Take air density = 1.225kg/m3, the plan form area of wing = 0.1 m2. the lift and drag coefficients as 1.4 and 0.01 respectively. Calculate : a. lift force b. drag forcec. resultant force d. aerodynamic coefficient (JNTU Feb 08)

1. With line diagram, explain how power can be generated from photovoltaic cells. (JNTU Feb 08)

2. List advantages and limitations of photovoltaic solar energy conversion. (JNTU Feb 08)

3. i. What is the principle of solar photovoltaic power generation? ii. Discuss in detail about the main components of a PV system.iii. What are the Applications of solar photovoltaic system? (JNTU Nov 04)

4. Explain the following with sketch: (JNTU Nov 04)i. Flat plate arrays of solar cell modulesii. Solar cell connecting arrangementsiii. Explain with a neat sketch, the operation of a central tower receiver system for power generation.

5. i. Discuss in detail about the solar cell principles. (JNTU May 04)ii. Derive the expression for calculating conversion efficiency and power output of a solar cell.

6. Advantages and limitations of photovoltaic solar energy conversion. (JNTU May 04)

7. Explain the following: (JNTU May 03)i. Solar cell ii. Solar module iii. Parabolic cylindrical concentrator

8. Derive the expression for calculating conversion efficiency and power output of a solar cell.(JNTU May 03)

9. With line diagram, explain a basic photovoltaic system for power generation. (JNTU May 03)

10. i. Explain photo voltaic cells in detail with diagrams (JNTU May 03)ii. What are advantages and disadvantages of solar cells

11. Explaining all necessary features, formulate the expression for calculating temperature distribution and collection efficiency of a solar pond. (JNTU Nov 02)

12. With the help of schematic diagram, explain solar passive space cooling system through ventilation.

13. With the help of schematic diagram explain solar process steam system.

14. What is the main advantage of using a glass cover in a box type cooker?

15. What is the maximum temperature obtained in a solar furnace?

16. What are the main advantages and disadvantages of a solar furnace?

17. What is the purpose of double layer of flazing in a greenhouse?

18. What features of solar energy make it attractive for use in irrigation water pump?

19. With the help of schematic diagram, explain the working of solar thermal water pump?

20. With the help of schematic diagram, explain the working of distributed collectors solar thermal electric power plant.

21. Give a neat diagram of a central tower receiver power plant and explain its operation. Give the details of an operation plant if such a plant exists any where in the world.

22. Classify the methods of solar energy storage. Describe thermal energy storage system.

23. Describe in brief, the different energy storage methods used in the solar system.

24. What is principle collection of solar energy used in a non-convective solar pond? Describe a non-convective solar pond for solar energy collection and storage?

25. What are the main applications of a solar pond? Describe briefly.

26. Write short notes on :i. Maintenance of stable density gradient in a solar pond ii. Heat extraction method from a solar pond.iii. Chemical energy storage method.iv. Hydrogen storagev. Electro-magnetic energy storage

27. Explain solar pond with neat figure.

28. Explain the following:i. P.V. Cell ii. P.V. Module iii. P.V. Array

29. What are advantages and disadvantages of solar cells.

UNIT – IV

3. i. Enumerate the advantages and disadvantages of wind power.ii. Write short notes on potential wind power in India.iii. List few companies manufacturing WEC devices. (JNTU Nov, Feb 08)

4. i. What is the basic principle of OTEC? Discuss the advantages of the closed cycle system over open cycle system.

ii. The efficiency of power plant working on OTEC system is very less. However, the secondary advantages make it commercially attractive. Discuss. (JNTU Nov 08)

3. i. Why a tall tower is essential for mounting a horizontal axis wind turbine?ii. Why should be a rotor of Darrieus type be located at a height?

iii. A wind turbine has rotor diameter of 15m. The wind speed is 7m/s. Assume normal temperature and air pressure. Energy utilization factor is 0.7. Efficiency of WTG unit is 35%. Calculate the electrical power delivered. (JNTU Nov 08)

1. i. Enumerate the advantages and disadvantages of wind power.

ii. Write short notes on potential wind power in India.

iii. List few companies manufacturing WEC devices. (JNTU Feb 08, Nov 07, May 03)

2. i. Explain the working of grid connected wind turbine generator with neat sketch.

ii. How do you select a suitable electric generator for wind turbine? (JNTU Feb 08, May 03)

3. In a wind turbine, the cambered aerofoil blades are subjected to a wind velocity of 10m/s. Take air

density = 1.225 kg/m3, the plan form area of wing = 0.1 m2. The lift and drag coefficients as 1.4 and

0.01 respectively. Calculate :

a. lift force b. drag force c. resultant force d. aerodynamic coefficient. (JNTU Feb 08)

4. i. Explain planetary winds and local winds.

ii. Derive an expression for power available in wind.

iii. Discuss the advantages and disadvantages of wind energy conversion systems. (JNTU Feb 08)

2. Discuss the methods of harnessing wave energy. (JNTU Feb 08)

5. i. Describe the working of a vertical axis Savonius Rotor with a neat sketch.

ii. What are the advantages and disadvantages of Savonius rotor. (JNTU Nov 07)

6. i. Explain the concept of Darrieus rotor principle.

ii. Describe the working of vertical axis Darrieus type vertical axis machine with a neat sketch.

(JNTU Nov 07)

7. i. Describe the main considerations in selecting site for locating wind generators

ii. Describe in detail the basic components of wind electric system. (JNTU Nov 04)

8. i. With a neat sketch explain the function of the different components of a horizontal axis type aero

generator.

ii. Explain the following terms and their significance.

a. Solidity ratio b. Tip speed ratio. (JNTU Nov 04)

9. Explain the following terms: (JNTU Nov 04)

i. torque coefficient ii. yaw control iii. blade design iv. types of turbine towers.

10. Explain the following: (JNTU Nov 04)

i. Savonius rotor ii. cut in speed iii. cut off speed iv. yaw and pitch control.

11. i. Derive an expression for power Coefficient of Wind energy conversion system.ii. Prove that in case of horizontal axis wind turbine maximum power can be obtained when interference

factor is 1/3. (JNTU May 04)

12. i. What control arrangements are used with a wind mill when the speed of wind exceeds the rated speed?

Illustrate your answer with neat sketch.

ii. Explain with neat sketch a suitable windmill for water pumping. (JNTU May 04, 03)

13. i. Discuss the advantages and disadvantages of horizontal and vertical axis wind mill.

ii. What methods are used to overcome the fluctuating power generation of windmill?

(JNTU May 04, 03)

14. i. How are WEC systems classified? Discuss in brief. (JNTU May 04)

ii. Discuss the advantages and limitations of wind energy conversion systems.

15. Wind at 1 standard atmospheric pressure and 15 deg.C has a velocity of 15 m/s. Calculate:

i. total power density in the wind streamii. the maximum obtainable power densityiii. the total power andiv. the torque and axial thrust (JNTU Nov 03)

Given: turbine diameter = 120m and turbine operating speed = 40 rpm at maximum efficiency.

Propeller type wind turbine is considered.

16. Wind at 1 standard atmospheric pressure and 15 deg.C temperature has a velocity of 10 m/s. The

turbine has diameter of 120m and its operating speed is 40 rpm at maximum efficiency. Calculate:

i. the total power density in the wind stream

ii. the maximum obtainable power density assuming efficiency = 40%

iii. the total power produced in kw and the torque and axial thrust (JNTU Nov 03)

17. In a wind turbine, the cambered aerofoil blades are subjected to a wind velocity of 10m/s. Take air

density = 1.225 kg/m3, the plan form area of wing = 0.1 m2. The lift and drag coefficients as 1.4 and

0.01 respectively. Calculate: (JNTU Nov 03)

i. lift force ii. drag force

iii. resultant force iv. aerodynamic coefficient

18. i. Why a tall tower is essential for mounting a horizontal axis wind turbine? (JNTU Nov 03)

ii. Why should be a rotor of Darrieus type be located at a height?

iii. A wind turbine has rotor diameter of 15m. The wind speed is 7m/s. Assume normal temperature and

air pressure. Energy utilization factor is 0.7. Efficiency of WTG unit is 35%. Calculate the electrical

power delivered. (JNTU Nov 03)

19. i. Describe the different schemes for wind electric generation. (JNTU May 03)

ii. Describe the generator control system.

20. Briefly explain the following: (JNTU May 03)

i. Upwind & down wind location of towers.

ii. Wind direction & speed measurement.

21. Describe the followings: (JNTU May 03)

i. wind energy storage ii. solar and wind interconnected system

22. i. What are the factors to be considered in design of wind turbine and explain.

ii. Describe the following: (JNTU May 03)

a. power control b. over speed control

23. Describe the main considerations in selecting site for wind generators. (JNTU Nov 02)

24. Explain with neat sketch construction and working of wind mill for water pumping.(JNTU Nov 02)

25. Describe in detail the basic components of wind electric system. (JNTU Nov 02)

26. Explain the operation and control of horizontal axis wind turbine generator unit with neat sketch.(JNTU Nov 02)

27. i. Explain planetary winds and local winds. (JNTU Nov 02)ii. Derive an expression for power available in wind.

28. i. Neatly draw different types of rotor for vertical axis wind machine. (JNTU Nov 02)ii. Explain power-velocity characteristics of wind turbine

29. i. What are the latest developments in wind generated electrical plants? (JNTU Nov 02)ii. Explain the variation of power coefficient with tip speed ratio.

30. Explain planetary and local winds.

31. How do we select site for wind power generation.

32. Classify wind energy conversion systems.

33. Explain horizontal axis type aero generator with neat figure.

34. Explain wind mill for water pumping with neat figure.

35. What methods are used to overcome the fluctuating power generation of windmill?

36. Explain Up-wind & down wind location of tower.

37. Explain wind direction & speed measurement.

38. Wind at 1 standard atmospheric pressure and 200C has a velocity of 16 m/s. Calculate:i. total power density in the wind stream ii. the maximum obtainable power densityiii. the total power and iv. the torque and axial thrust

Given: turbine diameter = 100m and turbine operating speed = 35 rpm at maximum efficiency. Propeller type wind turbine is considered.

39. What are the basic components of wind electric system.

40. Derive an expression for power available in wind.

41. A wind turbine has rotor diameter of 12m. The wind speed is 6.5m/s. Assume normal temperature and air pressure. Energy utilization factor is 0.75. Efficiency of WTG unit is 34%. Calculate the electrical power delivered.

42. What control arrangements are used with a wind mill when the speed of wind exceeds the rated speed? Justify with neat sketch.

UNIT – V

5. Discuss the methods of harnessing wave energy. (JNTU Nov 08)

5. Discuss the various wave energy conversion devices. (JNTU Nov 08)

1. i. What are the different inputs which produce Biogas? List out the factors affecting bio-digestion.ii. Give a neat sketch of Biogas production plant for domestic use for a family of 5-6 persons.iii. Explain “Energy Plantation” and state its advantages and disadvantages.


2. i. What are the methods for obtaining energy from Bio-mass? Explain in brief.ii. Describe the operation of Bio-gas plant with a neat sketch. (JNTU Feb 08)

2. i. What are the different inputs which produce Biogas? List out the factors affecting bio-digestion?ii. Give a neat sketch of Biogas production plant for domestic use for a family of 5-6 persons.

iii. Explain “Energy Plantation” and state its advantages and disadvantages. (JNTU Feb 08)

3. i. How are biogas plants classified? Explain the batch type and floating drum type of bio-digesters with sketch.

ii. What are the advantages and disadvantages of floating drum plant?iii. Enumerate the advantages and disadvantages of fixed dome type plant. (JNTU Feb 08, Nov 07)

4. i. What is meant by anaerobic digestion? What are the factors, which affect bio-digestion? Explain briefly.

ii. What is a community biogas plant? What are the main problems encountered in its operation?(JNTU Nov 07)

5. i. What is the difference between biomass and Biogas? (JNTU Nov 07, 04)ii. What are the techniques suggested for maintaining the biogas production?iii. What is community biogas plant? What are the main problems encountered in its operation?

6. i. With a help of a neat sketch explain the working principle of any one type of biogas plant? ii. What are the techniques suggested for maintaining the biogas production? Explain. iii. What are the main applications of biogas. (JNTU Nov 04, 03)

7. Calculate:i. Steam required. ii. Heat rate.iii. Plant efficiency and iv. Cooling water rate. (JNTU Nov 04)

8. i. Explain with a neat sketch of a bio-gas plant for producing biogas by ‘Anaerobic Fermentationii. Calculate

a. The volume of a biogas digester suitable for the output of four cows.b. The power available from the digester. Retention time is 14 days, temperature 300C, dry matter consumed 2kg/day. biogas yield 0.24 m3 kg-1, burner efficiency 0.6, methane proportion 0.8 given the heat of combustion of methane as 28MJ/m3. (JNTU Nov 04)

9. i. What is community biogas plant? What are the main problems encountered in its operation?ii. How biogas can be used as a fuel in I.C engine? Explain the working of such engine with neat sketch.

(JNTU May 04)

10. i. How bio-gas can be utilized in Spark ignition engine? Explain with neat sketch. (JNTU May 04)ii. What is meant by anaerobic digestion? What are the factors which affect biodigestion? Explain briefly.

11. i. How are biogas plants classified? Explain the dome with a sketch type plant. (JNTU May 04)ii. What are the various phases of anaerobic digestion in a Biogas plant? Discuss them in brief.

12. i. What are the techniques suggested for maintaining biogas production? Explain.ii. How biogas plants are classified? Explain continuous and batch type of plants with advantages and

disadvantages of each one. (JNTU May 04)

13. What is meant by anaerobic digestion? What are the factors, which affect biodigestion? Explain briefly? (JNTU Nov 03, 02)

14. i. How are biogas plants classified? Explain the batch type and floating drum type of biodigesters with sketch.

ii. What are the advantages and disadvantages of floating drum plant?iii. Enumerate the advantages and disadvantages of fixed dome type plant. (JNTU Nov 03)

15. Explain in detail the various principal routes of Bio mass energy conversion to useful energy?(JNTU Nov 03, 02)

16. Explain the constructional details and working of KVIC (Khadi Village Industries Commission) digester.

17. i. What is meant by wet fermentation and dry fermentation? (JNTU May 03)ii. What are the main problems in straw fermentation? How they are minimised?

18. Explain the concept of hot dry rock geothermal power plant. (JNTU May 03)

19. What is a community biogas plant? What are the main problems encountered in its operation?(JNTU May 03)

20. With a help of a neat sketch explain the working principle of any one type of biogas plant? Also enumerate the advantages of using community biogas plants. (JNTU May 03)

21. How the gasifiers classified? Explain briefly about Fluidised Bed Gasifiers? (JNTU Nov 02)

22. Explain the origin of Bio-mass energy in detail. Explain the difference between bio mass energy resources and fossil fuel. (JNTU Nov 02)

23. How are biogas plants classified? Explain continuous and batch type plants. (JNTU Nov 02)

24. Explain with neat sketch Deena Bhandu Bio-gas plant.

25. Explain the effect of Dung Loading on gas production.

26. Classify the bio-gas plants and explain each of them.

27. What are the advantages & dis-advantages of floating drum plant.

28. What are the advantages & dis-advantages of fixed drum plant?

29. Explain with neat sketch KVIC digester.

30. Write in details of commonly used bio-gas plaints in India.

31. Write the constructional details of KVIC digester.32. How do you extract bio-gas from plant wastes?

33. How do you select a site for a bio-gas plant?

34. What are the advantages of energy plantation?

35. Classify the bio-mass gasifiers & explain each of them.

36. Write chemistry of the gasification process.

37. What are the applications of gasifier.

UNIT – VI

6. i. Explain with neat sketches the energy extraction techniques from tidal wavesii. A tidal power development has total installed generation of 7500 MW operating at a maximum head of

8 m. The minimum head at the end of cycle of generation is 2.5 m after 5 hours. Assume two cycles of generation in 24 hr. The generated power decreases linearly from 7500 MW to zero. The turbine and generator have efficiencies of 93% and 97%, respectively. The length of embankment is 20 km. Calculate:i. Quantity of water flowing through the turbines a maximum output in m3/s.ii. Surface area of reservoir in km2.iii. Wash behind the embankment at maximum reservoir capacity.iv. Energy delivered per year at a load factor of 0.8. (JNTU Nov 08)

6. i. Explain various devices for tidal energy extractionii. What are the advantages and limitations of tidal energy? (JNTU Nov 08)

6. i. What are the factors affecting the suitability of site for the tidal power plants?

ii. Bring out a detailed classification of tidal power plants and describe one of them briefly drawing a sketch.

iii. Calculate the theoretical maximum power and the actual power output of a tidal electric power plant when the basin size is 10 km x 30 km and the tidal range is 4 meters. State, with reasons, the value of assumed efficiency. (JNTU Nov, Feb 08)

6. i. With reference to typical examples, explain the nature and magnitude of energy possessed by ocean tides.

ii. The observed difference between the high and low water tide is 0.85meters, for a proposed tidal site. The basin area is about 0.5sq. Km which can generate power for 3 hours in each cycle. The average available head is assumed to be 8 meters and the overall efficiency of generation to be 75%. Calculate the power in HP at any instant and the yearly power output. (JNTU Nov 08)

1. i. Explain the advantages and disadvantages of Geothermal energy over the other forms of energy.ii. What are the applications of Geothermal energy in the field of Agriculture? iii. Explain briefly the possible sources of Geothermal pollution? How these are avoided?

(JNTU Feb 08)

2. i. What are the sub classifications of hydrothermal convective system?ii. Describe a liquid dominated system or wet steam field.iii. A hot water geothermal plant of the total flow type, receives water at 2500C. The pressure at turbine

inlet is 10 bar. The plant uses a direct contact type condenser that operates at 0.3 bar. The turbine has a polytropic efficiency of 70%. For a cycle, net output of 10MW. Calculate:a. The hot water flow rate,b. The condenser cooling water flow rate,c. Cycle efficiency andc. Plant heat rate (JNTU Feb 08, Nov 07, 04)

3. i. Explain the concept of hot dry rock geothermal power plant.ii. Calculate the useful heat content per square kilometer of dry rock granite to a depth of 7km. Take the

geo-thermal temperature gradient at 300C/km, the useful temperature as 1500C above the surface temperature. Density of rock is 2700kg per m3 and specific heat of rock is 820 J/kg/k.

(JNTU Feb 08, Nov, May 04)

4. i. Explain Hot Dry rocks (petrothermal) resources of geothermal energy and how they can be exploited as a source of energy.

ii. Explain vapour dominated hydrothermal power plant with neat sketch and its representation on T-S diagram.

iii. Describe various disadvantages and operational problems associated with geothermal energy.(JNTU Feb 08, Nov 07, May 04)

5. i. Describe a Binary cycle system for liquid dominated system.ii. What are the limitations of a flashed steam system?iii. What are the advantages of double flash system? (JNTU Nov 07, 02)

6. i. Describe a vapour dominated or dry steam field.ii. A vapour dominated system of 100MW capacity uses saturated steam with a shut off pressure of 30 bar

and enters turbine at 5.0 bar and condenses at 0.15 bar. Polytropic efficiency of turbine is 80%, generator - turbine combined mechanical and electrical efficiency is 90% water output temperature from cooling tower is 200C. and reinjection occurs prior to cooling tower. Calculate:a. Steam required b. Heat rate c. Plant efficiency and d. Cooling water rate.(JNTU Nov 07)

7. Explain briefly the advantages and disadvantages of Geothermal energy forms?(JNTU Nov 04, 03, 02, May 04)


and enters turbine at 5.0 bar and condenses at 0.15 bar. Polytropic efficiency of turbine is 80%, generator – turbine combined mechanical and electrical efficiency is 90% water output temperature form cooling tower is 200C. and reinjection occurs prior to cooling tower. (JNTU Nov 04)

9. A 100 MW vapour – dominated system uses saturated steam from a well with a hut-off pressure of 25 N/m2 and steam enters the turbine polytropic efficiency at 80% and the turbine generator combined mechanical and electrical efficiency is 90%. The cooling tower exists at 200C. Calculate the necessary steam in Kg/hr, cooling water flow, plant efficiency and the heat rate: if rejection occurs prior to the cooling tower. (JNTU May 04)

10. i. Explain the origin of geothermal energy.ii. Calculate the initial temperature, and heat content per square kilometer above 400C, of an aquifer of

thickness 0.5km, depth 3km, porosity 5%, under sediments of density 2700kg m-3, specific heat capacity 840 J kg-1 K-1, temperature gradient 300C km-1, and the surface temperature is 100C. Also estimate the time constant for useful heat extraction at a rate of 100 liters /sec / sq. km.

(JNTU May 04)

11. i. What are the prospects of Geothermal energy in Indian context? (JNTU Nov 03)ii. Explain the schematic and thermodynamic cycle of any one type of geothermal power plant.

12. i. Show the cross-section of the earth and temperature of different depths. (JNTU Nov 03)ii. Explain how geothermal energy is used for power generation. iii. Derive an expression to estimate the energy content of a hot dry rock geo-thermal resource, assigning

linear variation of temperature. Hence obtain an expression for the time constant of a geo-thermal well.

13. Write a short note on prospects of Geothermal energy in context of India. (JNTU May 03)

14. Explain the schematic and thermodynamic cycle of any one type of geothermal power plant.(JNTU May 03)

15. Draw the schematic diagram of geothermal preheat hybrid system and explain. (JNTU May 03)

16. Explain the main applications of Geothermal energy? (JNTU Nov 02)

17. i. Define a Geothermal source.ii. Classify Geothermal sources.

18. What are the sub classification of hydrothermal convective system ? Describe a vapour dominated or dry steam field.

19. A 100 MW vapour-dominated system as uses saturated steam from a well with a shunt off pressure of 28 kg/cm2 a steam enters the turbine at 5.6 kg/cm2 a and condenses at 0.14 kg/cm2 a. The turbine poytropic efficiency is 0.82 and the turbine - generator combined mechanical and electrical efficiency is 0.90. The cooling tower exist is at 210C. Calculate the necessary steam, kg/hr, and m3/min; the cooling water flow, kg/hr, and the plant efficiency and heat rate, kcal/kwh, if reinjection occurs prior to the cooling tower.

20. What are the limitations of a flashed steam system?

21. What are the limitations of a flashed steam system? What are the advantages of double flash system?

22. Describe a Binary cycle system for liquid dominated system.

23. Describe the main types of turbines in brief, which may be used for Geothermal energy conversion.

24. What are the advantages and disadvantages of Geothermal energy forms?

25. What are the main applications of Geothermal energy?

26. What are the possible sources of Geothermal pollution? How these are avoided?

27. Give a brief note on prospects of Geothermal energy in context to India.

28. Explain hot dry rocks resources of geo-thermal energy.

UNIT – VII


and enters turbine at 5.0 bar and condenses at 0.15 bar. Polytropic efficiency of turbine is 80%, generator - turbine combined mechanical and electrical efficiency is 90%, water output temperature from cooling tower is 200C and reinjection occurs prior to cooling tower. Calculate:i. Steam required. ii. Heat rate. iii. Plant efficiency and iv. Cooling water rate.

(JNTU Nov 08)7. i. Describe a Binary cycle system for liquid dominated system.

ii. What are the limitations of a flashed steam system?iii. What are the advantages of double flash system? (JNTU Nov 08)

7. i. Explain Hot Dry rocks (petrothermal) resources of geothermal energy and how they can be exploited as a source of energy. (JNTU Nov 08)


iii. Describe various disadvantages and operational problems associated with geothermal energy.

5. Explain in brief the energy potential of ocean waves and methods of harnessing the wave energy.(JNTU Nov, Feb 08)

1. i. Draw the schematic diagram and explain the Open cycle OTEC system. What are the operational difficulties encountered in OTEC plants?

ii. Find the quantity of water to be pumped to OTEC plant working with surface water at 270 C and with cold water at 80 C at a depth of 600 m from the surface to obtain 1.0MW of energy. Assume the density of ocean water as 1010 kg/m3 and the specific heat of water as 4200 J/kg K.

(JNTU Feb 08, Nov 07, 08, May 04)2. i. Explain with neat sketches the basic principle of tidal power generation. What are the limitations of

each method.ii. A tidal project has installed capacity of 2176MW in 64 units each of 34MW rated output. The head at

rated output is 5.52m. The embankment is 6.4 km long. Assume 93% efficiency for both turbine and generators. The generation is 5 hours twice a day. Calculate:a. The quality of water flowing through each turbine.b. The surface area of reservoir behind the embankment. (JNTU Feb 08, Nov 03)

3. Derive expressions for power and energy from the waves. What are the limitations and advantages of wave energy conversion? (JNTU Feb 08)

6. i. How are tides formed? Show by sketches the methods of harnessing the energy potential associated with ocean tides.

ii. In any estuary, which is being developed for tidal power generation during the tide cycle the observed difference between the high and low water of the tide was 4.3m. It is estimated that the estuary’s area is 0.45 sq. km which can generate power for 3 hours in each cycle. Assuming the average available head to be 5m. and the overall efficiency of generation to b 65% calculate : i. The power in KW at any instant and ii. The total energy in the year (ρ = 1025 kg/m3 for sea water). (JNTU Feb 08)

4. i. Explain the operation of a closed cycle OTEC plant with neat diagram. ii. Estimate the amount of electrical energy obtained from an OTEC plant working with surface water at

270 C and with a temperature difference of 15o C. Assume the density of ocean water as 1010 kgim3, specific heat of water as 4200 J/kg K, turbine efficiency 0.75, generator efficiency 0.96 and diameter of tube 60 cm. The velocity of water is limited to 0.2 m/s. (JNTU Feb 08, May 04)

5. Discuss the methods of harnessing wave energy. (JNTU Feb 08, Nov 07)

6. i. What are the factors affecting the suitability of site for the tidal power plants?

ii. Bring out a detailed classification of tidal power plants and describe one of them briefly drawing a sketch.

iii. Calculate the theoretical maximum power and the actual power output of a tidal electric power plant when the basin size is 10 km x 30 km and the tidal range is 4 meters. State with reasons, the value of assumed efficiency. (JNTU Feb 08)

7. i. Draw a neat layout diagram of a typical OTEC plant showing salient features and explain the principle of operation.

ii. In a Claude’s cycle of OTEC conversion producing 100 KW power, warm water at 270C is admitted into flash-evaporator, where a pressure corresponding to saturation temperature of water at 25 0C is maintained. Saturated vapor is then sent through a turbine having a polytropic efficiency of 80%. The pressure in the direct contact condenser is maintained at a value corresponding to saturation temperature of water at 150C by means of deep sea cold water at 130C. Calculate.a. Turbine mass flow rate of vaporb. Mass flow rate of deep sea cold water.c. Mass flow rate of warm water.d. Gross cycle efficiency on the basis of energy available from warm surface water.Also explain the reasons of obtaining low value of efficiency. (JNTU Feb 08)

2. i. What are the sub classifications of hydrothermal convective system?ii. Describe a liquid dominated system or wet steam field.iii. A hot water geothermal plant of the total flow type, receives water at 2500C. The pressure at turbine

inlet is 10 bar. The plant uses a direct contact type condenser that operates at 0.3 bar. The turbine has a polytrophic efficiency of 70%. For a cycle, net output of 10MW. Calculate : i. The hot water flow rate,ii. The condenser cooling water flow rate,iii. Cycle efficiency and iv. Plant heat rate. (JNTU Feb 08)

8. Explain in brief the energy potential of ocean waves and methods of harnessing the wave energy.


10. i. Explain the operation of single pool modulated tidal system. What are its advantages compared to unmodulated system.

ii. In spite of the attractiveness of tidal power generation, discuss why tidal schemes are not being developed in the world as fast as one would like to talk about them. (JNTU Feb 08, May 04)

11. i. Explain the operation of a closed cycle OTEC system.ii. Discuss its advantages and disadvantages compared to open cycle OTEC plant. (JNTU Nov 07)

12. i. Describe the difference between spring tides, neap tides, high tide, and low tide.ii. Discuss the possible reasons why energy output in double-effect generation is usually lower than for

single-effect generation. (JNTU Nov 07, May 04)

13. i. Show by sketches the method of harnessing the energy potential associated with ocean tides.ii. A tidal power station has 24 generators each of 10 MW operating at a maximum head of 13.5m. It

generates for two 6 hour periods per day. Calculate the basin capacity in m3, and annual energy production. Assume 93% efficiencies. (JNTU Nov 07)

14. i. What is the basic principle of OTEC? Discuss the advantages of the closed cycle system over open cycle system. (JNTU Nov 07, 04, 03)

ii. The efficiency of power plant working on OTEC system is very less. However, the secondary advantages make it commercially attractive. Discuss.

15. Discuss the advantages and limitations of wave energy conversion. (JNTU Nov 07)

16. i. Explain with neat sketches the energy extraction techniques from tidal waves ii. A tidal power development has total installed generation of 7500 MW operating at a maximum head of

8 m. The minimum head at the end of cycle of generation is 2.5 m after 5 hours. Assume two cycles of generation in 24 hr. The generated power decreases linearly from 7500 MW to zero. The turbine and

generator have efficiencies of 93% and 97%, respectively. The length of embankment is 20 km. Calculate: a. Quantity of water flowing through the turbines a maximum output in m3/s.b. Surface area of reservoir in km2.c. Wash behind the embankment at maximum reservoir capacity.d. Energy delivered per year at a load factor of 0.8. (JNTU Nov 07)

17. i. What is the basic principle of OTEC? Discuss the advantages of the closed cycle system over open cycle system.

ii. The efficiency of power plant working on OTEC system is very less. However, the secondary advantages make it commercially attractive. Discuss. (JNTU Nov 07)

18. Describe the following schemes for tidal generation, with suitable figures:i. Ebb generation;ii. Flood generation;iii. Two-way generation;iv. Single-basin scheme;v. Two-basin scheme. (JNTU Nov 07, 04)

19. i. How energy is obtained from oceans ? Explain in detail (JNTU Nov, May 04)ii. Find the quantity of water to be pumped to OTEC plant to obtain 1 MWe working with surface water

at 270C and with a temperature difference of 150C. Assume the density of ocean water as 1010kg/m3, specific heat of water as 4200KJ/ kg, turbine efficiency is 0.75, generator efficiency is 0.96 and diameter of the tube is 60cm.

20. Derive expressions for power and energy from the waves. What are the limitations and advantages of wave energy conversion? (JNTU Nov, May 04)

21. i. Explain various devices for tidal energy extraction (JNTU Nov 04)ii. What are the advantages and limitations of tidal energy?

22. i. With a schematic diagram, explain briefly the working of open cycle OTEC plantii. What are its advantages and limitations of open system over closed cycle system?(JNTU Nov 04, 03)

23. Discuss the problems associated with the generation of power from ocean waves and describe with sketches the various methods of converting ocean wave energy into power. (JNTU Nov, May 04)

24. i. What are the different methods of getting power from tides? Describe them with neat sketches?ii. Calculate the theoretical maximum power and the reasonable obtainable power output of a tidal power

plant when the basin size is 10 km x 25 km and the tidal range is 3 meters.Assume a suitable efficiency value to take into account the frictional loss and inefficiencies in turbines and generators, state clearly this assumed value. (JNTU May 04, Nov 04)

25. Explain with neat sketches the following wave energy conversion devices. (JNTU Nov 04)i. Salter duck ii. Cockerell raft iii. Oscillating water column.

26. i. Classify tidal power plants in detail. (JNTU Nov 04)ii. What are the differences in tidal power developments?

27. Discuss the advantages and limitations of wave energy conversion. (JNTU Nov 04, 03)

28. With neat sketches explain the working of wave energy conversion machines (JNTU Nov 04, 03)

29. i. What are the main disadvantages of Claude’s cycle of OTE conversion system? ii. How these draw backs are removed in Anderson’s cycle. (JNTU May 04)

30. Discuss the various wave energy conversion devices. (JNTU May 04)

31. i. Show by sketches the method of harnessing the energy potential associated with ocean tides.

ii. A tidal power station has 24 generators each of 10 MW operating at a maximum head of 13.5m. It generates for two 6 hour periods per day. Calculate the basin capacity in m3, and annual energy production. Assume 93% efficiencies. (JNTU May 04)

32. Explain in brief the energy potential of ocean waves and methods of harnessing the wave energy.(JNTU Nov 03, May 04)

33. Explain the operation of a closed cycle OTEC plant with neat diagrams. (JNTU Nov, May, 03)

34. How are ocean waves formed? Explain with a schematic diagram how this energy can be tapped.(JNTU Nov 03)

35. i. With reference to typical examples, explain the nature and magnitude of energy possessed by ocean tides.

ii. The observed difference between the high and low water tide is 0.85meters, for a proposed tidal site. The basin area is about 0.5sq. Km which can generate power for 3 hours in each cycle. The average available head is assumed to be 8 meters and the overall efficiency of generation to be 75%. Calculate the power in HP at any instant and the yearly power output. (JNTU Nov 03)

36. i. Explain the working of ocean thermal energy conversion (OTEC) plant. (JNTU Nov 03)ii. Discuss the various equipment for the establishment of an off shore OTEC system.

37. i. How are tides formed? Show by sketches the methods of harnessing the energy potential associated with ocean tides. (JNTU Nov 03)

ii. In any estuary, which is being developed for tidal power generation during the tide cycle the observed difference between the high and low water of the tide was 4.3m. It is estimated that the estuary’s area is 0.45 sq. km which can generate power for 3 hours in each cycle. Assuming the average available head to be 5m, and the overall efficiency of generation to be 65%, calculate:a. The power in kW at any instant andb. The total energy in the year (r = 1025 kg/m3 for sea water).

38. i. Explain the various components of Tidal power plants. Discuss the single basin retaining dam tidal power generation method.

ii. A tidal power plant of simple single basin type, has basin area of 30 x 106 m2. The tide has a range of 12m. The turbine, however, stops operating when the head on it falls below 3m. Calculate the energy generated in one filling or emptying process, kWH, if the turbine generator efficiency is 75%.

(JNTU Nov 03)

39. Explain the various components of Tidal power plants. Discuss the single basin retaining dam tidal power generation method. (JNTU May 03)

40. Draw the schematic diagram and explain the Open cycle OTEC system. What are the operational difficulties encountered in OTEC plants? (JNTU May 03)

41. Explain with neat sketches the basic principle of tidal power generation. What are the limitations?(JNTU May 03)

42. Classify tidal power plants in detail (JNTU Nov 02)

43. Explain simple single pool tidal system with neat diagrams (JNTU Nov 02)

44. How energy is obtained from oceans? Explain in detail (JNTU Nov 02)

45. Explain various devices for tidal energy extraction. (JNTU Nov 02)

46. Describe the principle of total flow concept. Compare it with other system. (JNTU Nov 02)

47. How do you classify tidal power plants.

48. Describe single pool tidal system.

49. What are the various devices for tidal energy extraction.

50. Write in brief : i. Spring tide ii. Heat tide iii. High tide iv. Low tide

51. What are the various types of converting ocean wave energy in to power.

52. What do you mean by single & double effect generation.

53. Explain single basin & two basin schemes.

54. Write in brief : i. Scatter duck ii. Cockerell Raft iii. Oscillating column

55. Derive the expression for power & energy from wave energy.

56. What are the limitation and advantages of wave energy conversion?

57. Explain the operation of a closed cycle OTEC plant with neat diagrams.

58. The efficiency of power plant working on OTEC system is very less. However, the secondary advantages make it commercially attractive. Discuss.

59. How are tides formed? Show by sketches the methods of harnessing the energy potential associated with ocean tides.

UNIT – VIII

8. i. What are the different inputs which produce Biogas? List out the factors affecting bio-digestion.ii. Give a neat sketch of Biogas production plant for domestic use for a family of 5-6 persons.iii. Explain “Energy Plantation” and state its advantages and disadvantages. (JNTU Nov 08)

6. i. Explain the operation of single pool modulated tidal system. What are its advantages compared to unmodulated system.

ii. In spite of the attractiveness of tidal power generation, discuss why tidal schemes are not being developed in the world as fast as one would like to talk about them. (JNTU Feb 08)

1. i. Explain Hot Dry Rocks (petrothermal) resources of geothermal energy and how they can be exploited as a source of energy.


iii. Describe various disadvantages and operational problems associated with geothermal energy. (JNTU Feb 08)

1. Discuss the principle of MHD generation.

2. Derive the equations for the voltage and power output of an MHD generator.

3. An MHD generators has the following parameters.Plate area = 0.20 m2Distance between plates = 0.4 m2Flux density = 2 Wb/m2Average gas velocity = 1000 m/sConductivity of the gas = 10 mho/mCalculate the open circuit voltage and maximum power output.

4. With the following specifications for an MHD generator calculate (i) open circuit voltage and (ii) maximum power output.Plate area = 0.1 m2Distance between plates = 0.5 m2Flux density = 3 Wb/m2

Average gas velocity = 103 m/sGaseous conductivity = 10 mho/m

5. How MHD systems are classified ? Describe them in brief.

6. Describe an MHD open cycle system. What are the main advantages of an MHD power generation.

7. Describe an MHD closed cycle system, with its advantages amd disadvantages.

8. What are important factors to be considered while selecting materials for an MHD generators. Give names of the materials for electrodes and generator duct.

9. What are the various losses associated with operation of MHD Faraday generator.

10. Write short notes on :i. Materials for MHD Generatorii. Seedingiii. Super-conductivityiv. Gas-conductivity

11. What is Seebeck Thermo electric effect ?

12. How Seebeck coefficients vary with temparature ?

13. Describe briefly a thermoelectric power generator ?

14. Define figure of Merit for a thermoelectric generator ?

15. Derive the expression for efficiency of a thermoelectric generator.

16. The absolute thermoelectric ower of two materials (A and B) varies with the temparature as SA = 6 x10-9 T and SB = 4 x 10-9 T where T is Kelvins and aSA and SB are in voltys/ Kelvin. The materials are joined to form thermo couple whose hot and cold junctions are maintained at 300 and 100C, respectively. The materials have a negligible electrical resistivity and thermal conductivity.

i. Find the emf produced by the thermocouple.ii. If a current of l = 0.5 A is supplied to an external electrical device, find the power produced.iii. Find the Peltier heat rates absorbed and rejected at the junctions.iv. Find the thomson heat rates between the heat rates absorbed and those rejected is equal to the power

produced in (b).v. Find the efficiency of the system and compare it with a Carnot system operating between the same two

temperatures.

17. A thermocouple is composed of two materials. The thermoelectric power of each material is independent of temperature. The hot and cold junctions are at TH = 500 K and TC = 300K, respectively. Using the values SA = 2 x 10-4 V/K, SB = 4 x 10-4V/K, R = 100 ohms, and K (thermal conductance) = 3.33 x 10-7 W/K.

i. Find the open circuit voltage (i.e. the emf) of the thermocouple.ii. Find the short-circuit current of the device.iii. Find the figure of merit of the system.iv. Determine the optimum load resistance required to achive maximum efficiency and find this

efficiency.

18. Compute the figure of merit of the materials of a thermoelectric system with the following properties.

19. i. Describe the operation of thermionic converter.ii. Derive the expression for thermal efficiency of thermoelectric generator and prove that the optimum

value of M that gives the maximum thermal efficiency is

where , Z = figure of merit

and

20. A thermoelectric generator that will operate between 30 and 5000C is to be constructed of n-p semi-conductor with the following properties.

For this system that is designed to produce 500 W at highest possible thermal efficiency, find the number of element pairs, the maximum possible thermal efficiency, and the maximum possible power output. Assume that the cross-sectional area and length of n-leg are 1 cm2 and 1 cm respectively and that of p leg is 1 cm.

21. A thermoelectric generator operates between the temperature limits of 100 and 3000C. The cross-sectional area of n-type is 1 cm2 and the length is 1 cm. Using the optimum value for the product of internal resistance and overall thermal conductance (i.e. RK). Calculate the maximum geerator efficiency and the efficiency for maximum power. Also calculate the power output for both the cases.The following properties may be used.

22. A thermoelectric generator operates between 250 and 5500C. The average value of the Seebeck coefficient is 400 x 10-6 V/K, the generator resistance is 0.004 ohms and the thermal conductance is 0.035 W/k-m. Find the open circuit voltage, the maximum power output, and thermal efficiency for maximum power output.

23. Write short notes on i. Thermoelectric effectsii. Seebeck, Peltier and Thomson effectsiii. Multistage thermoelectric generatorsiv. Selection of Thermoelectric materialsv. Figure of merit of a thermoelectric generator.

7. SUBJECT DETAILS

7.2 ELECTRICAL DISTRIBUTION SYSTEMS


7.2.2 Scope

7.2.3 Prerequisites

7.2.4 Syllabus

i. JNTU

ii. GATE

iii. IES


7.2.6 Websites


7.2.8 Journals


7.2.10 Session Plan




i. JNTU

ii. GATE

iii. IES


Now a days interconnected Power System is complex and vary in sizes and configurations. The technical analysis of transmission line is done to know its performance. An Electric Power System consists of large equipments like generators, transformers and associated transmission and distribution network short circuits, voltage fluctuations and other abnormal conditions often occur on a power system which leads to heavy faults resulting damage to the power apparatus. The transmission and distribution systems are similar to man’s circulatory system. The transmission system may be compared with arteries in capillaries. They serve the same purpose of supplying the ultimate consumer in the city with the life-giving blood of civilization electricity. Hence it is mandatory for an Electrical Engineer to be aware of importance and operation of Distribution System.

5.5.2 SCOPE

This subject provides the knowledge of Distribution System of various Power System elements. Distribution System is that part of Power System which distributes power to the consumers for utilization. This leads to understand how either a Distribution System or electric substation is to be maintained for smooth functioning. It also makes one to know about protection of various elements from both internal faults like earth fault, short circuit faults etc. and external faults like lightning faults, power factor improvement and voltage control.

5.5.3 PREREQUISITES

It requires knowledge of Power systems, Network theory, Electrical machines, Prime movers, electrical and mechanical design of transmission lines and applied mathematics.

5.5.4 JNTU SYLLABUS

UNIT - IOBJECTIVE

Explains the general concepts about Distribution System different types of factors and loads.

SYLLABUS General : Introduction to Distribution systems, an overview of the role of computers in distribution system planning-Load modeling and characteristics: definition of basic terms like demand factor, utilization factor, load factor, plant factor, diversity factor, coincidence factor, contribution factor and loss factor-Relationship between the load factor and loss factor - Classification of loads (Residential, Commercial, Agricultural and Industrial) and their characteristics.

UNIT -IIOBJECTIVE

This unit is meant for explaining different types of distribution feeders and their voltage levels.

SYLLABUS

Distribution Feeders and Substations : Design consideration of Distribution feeders: Radial and loop types of primary feeders, voltage levels, feeder-loading.Design practice of the secondary distribution system.

UNIT - IIIOBJECTIVE

This unit mainly dealt with rating of substations, location of sub stations.

SYLLABUS

Location of Substations : Rating of a Distribution Substation, service area with primary feeders. Benefits derived through optimal location of substations.

UNIT – IVOBJECTIVE

This unit explains about system analysis of voltage drop and power loss calculations. SYLLABUS

Voltage drop and power loss calculations : Derivation for volt-drop and power loss in lines, manual methods of solution for radial networks, three-phase balanced primary lines, non-three-phase primary lines.

UNIT-VOBJECTIVE

This unit explains about protection of Distribution System and different types of protective devices.

SYLLABUS

Protective devices and coordination : Objectives of distribution system protection, types of common faults and procedure for fault calculation.

UNIT-VIOBJECTIVE

This unit explains about co-ordination of different protective devices.

SYLLABUS

Protective Devices: Principle of operation of fuses, circuit reclosers, line sectionalizer and circuit breakers. Coordination of protective devices : General coordination procedure. UNIT-VIIOBJECTIVE

This unit explains about capacitive compensation for power factor control.

SYLLABUS

Capacitive compensation for power factor control: Different types of power capacitors, shunt and series capacitors, effect of shunt capacitors (Fixed and switched) power factor correction, capacitor location. Economic justification. Procedure to determine the best capacitor location.

UNIT-VIIIOBJECTIVE

This unit explains about equipment for voltage control and line drop compensation.

SYLLABUS

Voltage control : Equipment for voltage control, effect of series capacitors, effect of AVB/AVR, line drop compensation.

5.5.3.ii SYLLABUS – GATE

UNIT-ILoad modeling and characteristics

UNIT-IINIL.

UNIT-IIINil.

UNIT-IVSystem Analysis

UNIT-VProtective devices.

UNIT-VINil

UNIT-VIICapacitive compensation for power factor control.


5.5.3.iii SYLLABUS – IES

UNIT-ILoad modeling and characteristics

UNIT-IINil

UNIT-IIINil

UNIT-IVSystem Analysis

UNIT-VProtective devices.

UNIT-VINil

UNIT-VIICapacitive compensation for power factor control.



TEXT BOOKS

1. Electric Power Distribution system, Engineering by Turan Gonen, MC Graw Hill Book Company

2. Principles of Power System by V.K.Mehta, Rohit Mehta.3. A Text Book on Power System Engineering by Soni Gupta, Bhatnagar. REFERENCES

1. Electric Power distribution by A.S.Pabla, Tata Mc Graw Hill Publishing Company, 4th Edition, 1997.

2. A Course in Electrical Power by J.B. Gupta.

3. Electric Power Generation, Transmission and Distribution by S.M.Singh.

5.3.6 WEBSITES

1. www.ntu.ac.sg2. www.utoronto.ca3. www.ee.washington.edu4. www.esca.com5. www.ne.ac.sg6. www.iitm.ac.in7. www.iitb.ac.in8. www.iitk.ac.in9. www.annauniv.edu10. www.vjti.ac.in.11. www.ieeecss.org12. www.ieee.com13. www.iee.com14. www.google.com



Designation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : NIT-Warangal – 506004.Phone No. : +91-870-2431616(O)Email : [email protected]

2. Name : Prof. D.M.Vinod KumarDesignation : ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : NIT-Warangal – 506004.Phone No. : +91-870-2431616(O)Email : dvmk @nitw.ac.in

3. Name : Dr. Bhagwan K.MurthyDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : NIT-Warangal – 506004.Phone No. : +91-870-2431616(O)Email : [email protected]

4. Name : V.T. SomashekharDesignation : Associate ProfessorDepartment : Electrical and Electronics EngineeringOffice Address : NIT-Warangal – 506004.Phone No. : +91-870-2453416 (O) Email : [email protected], [email protected]

5. Name : Dr. A.D.RajkumarDesignation : ProfessorDepartment : Electrical EngineeringOffice Address : University College of Engineering, Osmania University, Hyderabad-500007Phone No. : +91-040-27682382 (O)Email : [email protected]

6. Name : Dr. M. VijayakumarDesignation : Associate ProfessorDepartment : Electrical EngineeringOffice Address : JNTU College of Engineering, Ananthapur, A.PEmail : www.jntu.ac.in

mailto:[email protected]

7. Name : Prof. ShankarramDesignation : ProfessorDepartment : Electrical EngineeringOffice Address : JNTU College of Engineering, Kukatpally, HyderabadEmail : www.jntu.ac.in

NATIONAL


Dy. Director (Administration.), IIT - Delhi,Hauzkhas, New Delhi - 110016.

Phone No. : +91-11-26591250 (O) , Fax : 91-11-26862037,Email : [email protected], [email protected]

2. Name : Dr. S.V. Kulkarni,Designation : Associate Professor,Department : Electrical and Electronics EngineeringOffice address : IIT, Bombay, Powai, Mumbai - 400076, India,Phone No. : +91- 22-25671098,Email : [email protected]


Office Address : Room No. II/211, IIT Delhi Phone No. : +91 11 2659 1094 ,91 11 2659 1886

Email : [email protected]

4. Name : Dr. Sivaji ChakravortiDesignation : Professor,Department : Electrical and Electronics engineeringOffice Address : Jadavpur University Kolkatta - 700032, IndiaEmail : [email protected], [email protected]

INTERNATIONAL

1. Name : Gary S. MaryDesignation : ProfessorDepartment : School of Electrical EngineeringOffice address : Georgia Institute of Technology, USA.Email : [email protected]

2. Name : Dr. Clayton R Paul, Designation : ProfessorDepartment : Electrical and Computer Engineering,Office Address : School of Engineering, Mercer University, Macom, Georgia-31207,Phone No. : (912) 301-2213,website : www.faculty.mercer.paul_cr

3. Name : Jushan ZhangDesignation : Associate ProfDepartment : Dept. of Electrical EngineeringOffice address : Ira A.Fulton School of Engineering, Arizona State University. Tempe, AZPhone No. : 85287-7206Email : Jushan Zhang @ee.gatech.edu


University of Hongkong, Hongkong.Phone No. :Email : [email protected]

5.3.8 JOURNALS



3. Name of the Journal : IEE Proceedings: Part-C [Generation, Transmission & Distribution]











5.5.9 FINDINGS AND DEVELOPMENTS

1. Title : General Public Exposure by ELF fields of 150-36/11kV substations in Urban environment

Author : W.Joseph, L.Verlock, L.MartensJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 495

2. Title : Computerised Analysis of grounding plates in multilayer soilsAuthor : J.Ma, F.P. DawalibiJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 650

3. Title : Minimum distance of Lightning Protection Between Insulator String and Line Surge Arrester in Parallel

Author : J.He, J.Hu, Y.Chen, S.ChenJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 656

4. Title : A Multi Purpose Balanced Transformer for Railway Traction Applications

Author : Z.Zhang, B.Wu, J.Kang, L.LuoJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 711

5. Title : Optimal Cost Benefit for the location of Capacitors in Radial Distribution System

Author : H.M.Khodr, A.Vale, C.RamosJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 787

6. Title : Analytical Study of Voltage Magnification Transients Due to Capacitor switching

Author : A.Kalyuzhny, S.Zissu, D.SheinJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 797

5.5.10 SESSION PLAN


No. Suggested Books

UNIT – I – GENERAL CONCEPTS (No. of Lectures – 09)

1

Introduction to Distribution System, an overview of the role of computers in Distribution System planning

Introduction to Distribution System L1 T1-Ch1 (P:3-17)T3-Ch1 (P:3-5)R1-Ch2 (P:1-25)R2-Ch10 (P:313-316)R3-Ch3 (P: 25-42)

An overview of the role of computers in Distribution System planning

L2L3

2 Load modeling and characteristics

Demand factor utilization factor, load factor, plant factor L4 T1-Ch2 (P:37-54)

T2-Ch3 (P:41-68)T3-Ch8 (P:96-157)R1-Ch2 (P:26-74)R2-Ch11 (P:245-314)R3-Ch4 (P: 43-63)

GATEIES

Diversity factor, coincidence factor, contribution factor and loss factor L5

Relationship between the load factor and loss factor L6

3 Classification of loads and their characteristics

Residential, commercial loads L7 T1-Ch2 (P:55-66)T2-Ch3 (P:41-68)T3-Ch8 (P:108-157)R1-Ch2 (P:26-74)R2-Ch11 (P:245-314)R3-Ch4 (P: 43-63)

Agricultural and Industrial loads L8

Problems L9

UNIT – II – DISTRIBUTION FEEDERS (No. of Lectures – 06)

4 Design considerations of distribution feeders

Radial loop types of primary feeders

L10L11


Voltage levels, feeder loading L12

5Basic design practice of the secondary distribution system

Basic design practice of the secondary distribution system

L13L14


Problems L15

UNIT – III – SUBSTATIONS (No. of Lectures – 05)

6 Location of Substations

Rating of distribution substation L16 T1-Ch4 (P:174-201)T2-Ch25 (P:565-585)T3-Ch15 (P:489-497)R1-Ch4 (P:156-162)R2-Ch17 (P:513-537)R3-Ch18 (P:383-394)

Service area with in primary feeders L17L18

Benefits derived through optimal location of substations

L19L20

UNIT – IV – SYSTEM ANALYSIS (No. of Lectures – 10)

7 Voltage drop and power loss calculations

Voltage drop and Power Loss calculations L21


GATEIES

Derivation for voltage drop in lines L22L23

Derivation for Power loss in lines L24L25

Manual methods of solution for radial networks

L26L27

3-phase balanced primary lines L28L29

Problems L30

UNIT – V – PROTECTION (No. of Lectures – 05)

8 Protection of Distribution System

Objective of distribution system protection L31 T1-Ch10 (P:528-531,

545-561)T2-Ch17 (P:395-421)T2-Ch18 (P:422-459)T3-Ch14 (P:470-483) GATE

IES

Types of common faults and procedure for fault calculations

L32L33

9 Protective DevicesPrinciple of operation of fuses, circuit reclosures line sectionalizer and CB

L34L35


UNIT – VI – CO-ORDINATION (No. of Lectures – 04)

10 Co-ordination of protective devices

Objective of co-ordination of protective devices L36 T1-Ch10 (P:531-545)


General co-ordination procedure L37L38

Co-ordination between different protective devices

L39L40

UNIT – VII – COMPENSATION FOR POWER FACTOR IMPROVEMENT (No. of Lectures – 09)

11 Compensation for power factor improvement

Capacitive compensation for power factor control L41


GATEIES

Different types of power capacitors, shunt and series capacitors, effect of shunt capacitors (Fixed and switched)

L42L43

Power factor correction capacitor allocation

L44L45

Economic justification L46L47

Procedure to determine the best capacitor location L48

Problems L49UNIT – VIII – VOLTAGE CONTROL (No. of Lectures – 07)

12 Voltage control

Equipment for voltage control L50T1-Ch9 (P:452-492)T2-Ch15 (P:374-386)T3-Ch11 (P:418-427)R1-Ch4 (P:168-178)R2-Ch16 (P:494-512)R3-Ch18 (P:383-394)

GATEIES

Effect of series capacitors L51L52

Effect of AVB/AVR L53L54

Line drop compensation L55L56


1. Title : High Frequency Loss in Unjacketed distribution Cable and Its Effects on PD Measurement

Author : C.Xu, S.A. BoggsJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 495

2. Title : New distortion and Unbalance Indices Based on Power Quality Analyzer Measurements

Author : P.Salmeron, R.s. HerreraJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 501

3. Title : Experimental evaluation of EMTP-based current transformer models for protective relay transient study

Author : M. KazunovicJournal : IEEE Transactions on Power DeliveryVol., Year & Page No. : Vol.9, No.1, PP 405-413, Jan. 1994.

4. Title : The laboratory investigation of a digital system of the protection of transmission lines

Author : W.D. Breingan, T.F. Gallen and M.M. ChenJournal : IEEE Transactions on Power SystemsVol., Year & Page No. : Vol.98, No.2, PP 350-368, April 1979.

5. Title : Effect of Voltage Profile in Distribution Transformer - losses and Energy Savings

Author : V.Saravanan, P.S. KannanJournal : S.Kannan at National Conference on Emerging Trends in Electrical

Engineering and Power Drives (NACPED - 05), Tirunelveli, Tamil Nadu,

Vol., Year & Page No. : PP : 103.

6. Title : Extended fault Location formation for Power Distribution SystemAuthor : R.H. Salim, M.RosenerJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 508

7. Title : Effect of Neutral Path Power Losses on Apparent Power Definitions : A Preliminary Study

Author : S.Pajic, A.E. EmannuelJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 517

8. Title : A New Digital Feed Circuit protection Using directional ElementAuthor : M.M.EissaJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 531

9. Title : Fault Classification and Faulted-Phase Selection Based on the Initial Current Traveling wave

Author : X.Dong, W.Kong, T.CuiJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 552

10. Title : Reactive Compensation using STATCOMAuthor : K.Prem Kumar N.SateeshJournal : NCAEE - 2005, BIHER, ChennaiVol., Year & Page No. : PP : 276-283.

11. Title : A Morphological Scheme for In rush Identification in Transformer Protection

Author : Z. Lu, W.H.Tang, T.Y.Ji,, QH. WnJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 560

12. Title : Response Bounds of Indoor Power Line Communication System with Cyclo-stationary Loads

Author : S.Barnada, A.Msolino, M.TucciJournal : Power Delivery, IEEE TransactionVol., Year & Page No. : Apr. 2009, Volume: 24, Page(s): 596


UNIT-I

1. a. What is the need for mathematical models to represent the system? Name the different operations research techniques used by planners, for planning a distribution system. (JNTU May 09)

b. Discuss about the three factors which affect the distribution system planning in the near future.

2. a. Explain how the load growth in a distribution system can be obtained.b. A distribution substation experiences an annual peak load of 3,500kW. The total annual energy

supplied to the primary feeder circuits is 107kWh. Findi. the annual average factorii. The annual load factor (JNTU May 09)

3. a. Explain load modeling and its characteristics. (JNTU May 09)b. Write in detail about commercial and agricultural loads and their respective characteristics.

4. a. Explain briefly by the factors affection system planning. (JNTU May 09)b. With neat block diagram explain the function of current distribution system planning process.

5. a. List out and explain the various control functions in distribution automation.b. The annual peak load input to a primary feeder is 2000 Kw. A computer program which calculates

voltage drops and copper looses shows that the total copper loss at the time of peak load is ΣI 2R= 100 Kw. The total annual energy supplied to the sending end of feeder is 5.61x106 Kwh, Theni. Determine the annual loss factorii. Calculate the total annual copper loss energy and its value at $ 0.03/Kwh.

6. a. Explain the following:i. coincidence factor ii. contribution factor iii. loss factor (JNTU May 09)

b. Write in detail about Residential and industrial loads and their respective characteristics.

7. Draw the schematic view of a distribution system planning and explain the role of computer in distributions system planning. (JNTU May 09, Mar 06)

8. a. Explain the characteristics of different types of load models b. Assume that the annual peak load of a primary feeder is 2,000kW, at which the power is 80kW per

three phase. Assuming an annual loss factor of 0.15, determinei. the average annual power lossii. the total annual energy loss due to the copper losses of the feeder. (JNTU May 09, Nov 05)

9. Discuss the objectives of distribution system planning (JNTU May 09)

10. a. What is meant by the term load? How loads can be classified?b. Define : Demand, load duration curve and Annual load duration curve. c. Explain how maximum demand and average demand can be obtained from daily demand variation

curve. (JNTU May 09, Nov 08, 07, Mar 06)

11. Draw a block diagram in flow chart form for a typical distribution system planning process and explain the techniques for distribution planning. (JNTU Nov 08, Mar 06)

12. a. Discuss the effect of load factor and diversity factor on the cost of generation in a power system.b. Assume that the annual peak-load input to a primary feeder is 200kW. The total copper loss at the time

of peak-load is 100kW. The total annual energy supplied to the sending end of the feeder is 5.61x10 6

kW H. Determine. i. The annual loss factorii. The total annual copper loss energy and its value at Rs.1.5 per kWh.

(JNTU May 09, Nov 08, 07, 05, Mar 06)

13. Discuss the objectives of distribution system planning. (JNTU Nov 08, 05)14. a. Derive the relationship between the load and loss factors.

b. The input to a sub transmission system is 87.6 x 106 kWh annually. On the peak-load day of the year, the peak is 25,000kW and the energy input that day is 3 x 105 kWh. Find the load factors for the year and for the peak-load day. (JNTU Nov 08, Mar 06)

15. a. Explain briefly the classification of Loads. (JNTU Nov 08, 05)b. A power supply is having the following loads.

Type of load Maximum demand in kW

Diversity of Group Demand Factor

Domestic 1,500 1.2 0.8Commercial 2,00 1.1 0.8Industrial 10,000 1.25 1.0

If the overall system diversity factor is 1.35, determinea. Maximum demand b. Connected load of each type

16. Why loads are classified in distribution systems and how they are classified? Also explain their different characteristics. (JNTU Nov 08)

17. a. What is meant by load modeling and give their characteristics? (JNTU Nov 08)b. Define the following:

i. Coincidence factor ii. Load factoriii. Loss factor iv. Contribution factor.

18. a. Prove that approximate formula for loss factor(FLS) = 0.3FLD + 0.7FLD, where FLD = load factor.b. The annual average load is 1241 kW and monthly peak load is 3600kW. Find the load factor and loss

factor by using approximate formula. (JNTU Nov 08)

Examine the present trend for the future distribution system planning. (JNTU Nov 07)

19. a. Explain how the load growth in a distribution system can be obtained.b. A distribution substation experiences an annual peak load of 3,500kW. The total annual energy

supplied to the primary feeder circuits is 107 kWh. Find i. The annual average powerii. The annual load factor (JNTU Nov 07, 05, Mar 06)

20. a. What is the need for mathematical models to represent the system? Name the different operations research techniques used by planners for planning a distribution system.

b. Discuss about the three factors which affect the distributions system planning in the near future. (JNTU Mar 06)

21. Explain the various factors affecting the distribution system planning.(JNTU May 09, Mar 06, Nov 05)

22. a. Draw a schematic single line diagram of the electrical power system and explain its typical parts in detail.

b. What are the types of basic distribution system and explain. (JNTU Jan 04)

23. a. Write in detail about commercial and agricultural loads and their respective characteristics. b. What is the role of computers in distribution system planning? (JNTU Jan 04)

24. a. The central role of the computer in distribution planning-Explain?b. What are the various factors effecting the distribution system planning? (JNTU Oct 03)

25. a. Define, i. demand factor ii. Utilization factor iii. Diversity factor iv. Coincidence factorv. Loss factor.

b. The data is given is table 1 for the NL & NP’s load curve, note that the peak occurs at 5 pm. Determine the following.

i. The loss contribution factorii. The diversity factor for the primary feeder.iii. The diversified maximum demand of the load group.iv. The coincidence factor of the load group. (JNTU Oct 03)

26. a. Give the relationship between load factor and loss factor?b. Assume that the riverside distribution substation of the NL & NP company supplying Ghost town,

which is a small city, experiences an annual peak load of 3500KW. The total annual energy supplied to the primary feeder circuits 10,000000 KWH. The peak demand occurs in July or August and is due to air-conditioning load. i. Find the annual average demandii. Find the annual load factor. (JNTU Oct 03)

27. a. Explain the role of computers in distribution system planning and explain about automation.b. Define the following: Coincidence factor, Maximum demand, Plant Factor, Utilization factor, Loss

Factor, Average Demand, Diversity factor and Load Factor. (JNTU Jan 03)

28. a. Explain the importance of the distribution system. (JNTU Jan 03)b. There are four consumers of electricity having different load requirements at different time as follows:

Maximum Demand

Consumer 1 2kW at 9 p.m. 1.6 kW at 8 p.m. 15% load factor

Consumer 2 2kW at 12 p.m. 1 kW at 8 p.m. 500W Average Load

Consumer 3 8kW at 5 p.m. 5 kW at 8 p.m. 25% load factor

Consumer 4 4kW at 5 p.m. -- 1kW Average Load

Determine i. Diversity factor, ii. The load factor and average load of each consumer and iii. The average load and load factor of the combined load.

29. a. Mention distribution system models and explain about the system planning in the future. b. The annual peak load input to a primary feeder is 200kW. It is calculated that total copper loss at the

time of peak load is ∑I2R=100kW. The total annual energy supplied to the sending end of the feeder is 5.61 x 106kWh. i. Determine the annual loss factor and ii. calculate the total copper loss energy and its value at Rs.0.03/kWh. (JNTU Jan 03)

30. a. Derive the expression for the relation between the load and loss factors. b. Define primary feeder loading and give various factors affecting he design of it. (JNTU Jan 03)

31. a. Draw the block diagram of a typical distribution system planning process. (JNTU Mar 02)b. What are the factors to be considered for Distribution system planning in the future.

32. Define the following terms : a. Demand b. Utilization factor c. Plant Factor d. Load factor e. Demand Factorf. diversity factor g. coincidence Factor h. Load Diversity i. contribution Factorj. Loss Factor (JNTU Mar 02)

33. a. Explain the distribution system planning process with neat block diagram. b. Explain the factors affecting the distribution system planning in the future. (JNTU Apr 03)

34. a. Explain the role of computer in distribution system planning.b. What are the different types of load? And explain their characteristics. (JNTU Apr 03)

35. a. Explain the role of computers in Distribution System planning b. Derive the relationship between the load factor and loss factor.

c. Discuss the characteristics of the following categories of loads : Residential, Commercial, Agricultural and Industrial Loads.

36. Whys is the load on apower station variable? What are the effects of variable laod on the operation of he power station?

37. What do you understand by theload curve? What informations are conveyed by aload curve?

38. Define and explain the importance of the following term in generation:i. Connected Load ii. Maximum demand iii. Demand factor iv. average load

39. Explain the terms load factor and diversity factor. How do these factors influence the cost of generation?

40. Explain how load curves help in the selection of size and number of generating units.

UNIT – II

1. What are the various factors that are to be considered in selecting a primary feeder rating? Describe the arrangement with suitable diagram. (JNTU May 09)

2. a. Explain with neat sketches radial type and loop type sub transmission systems.b. What are the various factors that influence the voltage levels in the design and operation of the

distribution system? Explain.

3. a. Derive the relationship between the load and loss factors for three different cases when. i. Load is steady ii. For very short lasting peak. (JNTU May 09)

b. Annual peak load input to a primary feeder is 2000 kw at which the power loss is total copper loss at the time of peak load is ΣI2R = 100 Kw. The total annual energy supplied to the sending end of the feeder is 5.61 x 106 Kwh. Determine i. Annual Loss factor ii. Total annual copper loss energy and its value Rs 1.50/Kwh.

4. a. With neat sketches explain the various types of sub transmission systems.b. How the rating of distribution substation can be calculated. Explain taking a general case with ‘n’ no.

of feeders. (JNTU May 09)

5. a. Define the terms : (i) feeder and (ii) Distributor.b. State the differences between primary and secondary distribution lines as regards to voltage used, load

carried, number of conductors and size of insulators. (JNTU May 09)

6. a. How do you apply the concept of ABCD constants to radial feeders. b. Derive an equation for receiving end voltage. (JNTU May 09, Nov 07, Mar 06)

7. Draw the one line diagram of radial type primary feeder and mention the factors that influences the selection of primary feeder. (JNTU May 09, Nov 08, 07, 05)

8. What are the various factors that are to be considered in selecting a primary feeder rating? Describe the arrangement with suitable diagram. (JNTU Nov 08, 05, Mar 06)

9. a. What are the various factors that influence the voltage levels in the design and operation of th distribution system?

b. A 3 phase radial express feeder has a lone to line voltage of 22.0 kv at the receiving end, a total impedance of 5.25 + j10.95Ω/phase, and a load of 5 MW with a lagging power factor of 0.90. Determine the following : i. The line to neutral and line to line voltages at the sending end. ii. The load angle. (JNTU Nov 08, 07)

10. Give the various loading and voltage level factors that influence the design and operation of primary feeders. (JNTU Nov 08, Mar 06)

11. a. Assume that the service area pf a given feeder is increasing as a result of new residential developments. Determine the new load and area that can be served with the same percent voltage drop if the new feeder voltage level is increased to 34.5 kV from the previous voltage level of 12.47kV.

b. Discuss in detail the factors which influence the selection of primary feeder rating. (JNTU Nov 08)

12. a. Explain radial type primary feeder with neat diagram. b. Assume that feeder has a length of 2 miles and that the new feeder uniform loading has increased to 3

times the old feeder loading. Determine the new maximum length of the feeder with the same percent voltage drop if the new feeder voltage level is increased to 34.5kV from the previous voltage level of 12.47kV. (JNTU Nov 08)

13. a. Draw and explain one line diagram of typical primary distribution feeder. (JNTU Nov 08)b. Draw and explain one line diagram of secondary network of the distribution feeder.

14. a. What is meant by express feeder and give its importance in operation of radial type primary feeder?b. Explain different connection diagrams of radial primary feeder. (JNTU Nov 08)

15. Derive the equations for voltage drop and power loss in a radial feeder with uniformly distributed load. (JNTU Nov 07, 05)

16. What are the various factors that are to be considered in selecting a primary feeder rating? Describe the arrangement with suitable diagram. (JNTU Mar 06)

17. Explain various types of radial primary feeders with diagrams. (JNTU Nov 05)

18. a. What are the benefits derived through optimal location substations.b. Write about the design of secondary distribution system. (JNTU Jan 04)

19. a. Give the one-line diagram of typical distribution system? (JNTU Oct 03)b. Explain different substation bus-schemes? Give merits & demerits of any two schemes?

20. a. Draw the one-line diagram of typical primary distribution feeders and give the various and interrelated factors affecting the selecting on a primary feeder ratings.

b. Give some of the aspects affected by the primary feeder voltage levels in design and operation of distribution system. (JNTU Jan 03)

21. Draw the different substation bus schemes and explain its advantages and disadvantages.(JNTU Mar 02)

22. What are the different substation Bus-Schemes and mention its advantages and disadvantages. (JNTU Apr 03)

23. a. Explain the design considerations of Redial & Loop types of primary distribution feeders. b. Explain the basic design practice of the secondary distribution system.

24. Write short notes on the following : a. Distribution transformersb. 3-wire d.c. distribution.c. Primary distribution.

25. What do you understand by distributions system?

26. Draw a single line diagram showing a typical distribution system.

27. Define and explain the terms : feeder, distributor and service mains.

28. Discuss the relative merits and demerits of underground and overhead systems.

29. Explain the following systems of distribution : i. Radial system ii. Ring Main system iii. Interconnected systems

30. Discuss briefly the design considerations in distribution system.

31. With a neat diagram, explain the complete a.c. system for distribution of electrical energy.

32. Describe briefly the different types of d.c. distributors.

33. What are the advantages of a doubly fed distributor over singly fed distributor?

34. Derive an expression for the voltage drop for a uniformly loaded distributor fed at one end.

35. What is the purpose of interconnector in a d.c. ring main distributor?

36. Explain 3-wire d.c. system of distribution of electrical power.

37. What are the advantages of 3-wire distribution over 2-wire distribution.

38. Explain the use of rotary balancer in a 3-wire d.c. distribution system.

39. What is a booster? With a neat diagram, explain how it can be used on a feeder.

40. Show with a neat diagram how unbalanced loads in a 3-wire d.c. system cause unequal voltages on the two sides of the neutral.

UNIT – III

1. How do you analyse a substation service area with ‘n’ primary feeders(JNTU May 09, Nov 08, 07, 05, Mar 06)

2. a. What are the various substation bus schemes? Explain them with neat sketches.b. What are the advantages and disadvantages of switching schemes of

i. Single bus ii. Double bus double breaker? (JNTU May 09)

3. a. Explain radial feeders with uniformly distributed loadb. What is primary feeder loading? Explain factors affecting the loading in terms of

i. Design and ii. Decisions for feeder routing. (JNTU May 09)

4. a. Compare the various switching schemes by clearly mentioning the advantages and the disadvantages of each. (JNTU May 09)

b. Explain the Rectangular-Type Development and Radial- Type Development in case of feeders.

5. a. Compare the radial ,loop and ring main primary distribution systems on the basis of load ,reliability of supply and economy. (JNTU May 09)

b. How do you optimally locate the substations and explain the benefits derived from optimal location.

6. Explain the procedure for the location of a substation. Enumerate the various factors affecting the selection of site for a substation. (JNTU May 09)

7. Give detailed analysis of square shaped and hexagonal shaped distribution substation areas. (JNTU Nov 08, Mar 06)

8. a. What are the various factors that are to be considered in selecting substation location. b. Compare the four and six feeders patterns. (JNTU May 09, Nov 08, 05, Mar 06)

9. a. Explain the various factors to be considered to decide the ideal location of substation.b. Explain how to decide the rating of a distribution substation. (JNTU Nov 08, 05)

10. Compute percent voltage drop of substation service area supplied with ‘n’ primary feeders. Assume load is uniformly distributed. (JNTU Nov 08)

11. Calculate % voltage drop of hexagonally shaped area of distribution substation. (JNTU Nov 08)

12. Discuss the benefits, which are derived through optimal location of substations. (JNTU Nov 08)

13. a. Compare the service area of the four and six feeder distribution system when, i. Thermally limitedii. voltage drop limited.

b. derive the equation for K constrant in substation design? (JNTU Oct 03)

14. a. Explain the rectangular type development of the distribution feeder. (JNTU Mar 03)b. Compare the 3-phase balanced network with two-phase plus neutral (open-wye) laterals.

15. a. Explain the development of radial feeder with uniformly distributed load. (JNTU Mar 03)b. Compare the 3-phase balanced network with 1-phase two-wire with ungrounded neutral laterals.

16. a. What is voltage square rule and area-coverage principle and explain them with an example.b. Explain the radial type primary feeder with neat diagrams. (JNTU Jan 03)

17. Draw a single line diagram showing a typical distribution system.

18. Define and explain the terms : feeder, distributor and service mains.

19. Discuss the relative merits and demerits of underground and overhead systems.

20. Explain the following systems of distribution : i. Radial system ii. Ring Main system iii. Interconnected systems

21. Discuss briefly the design considerations in distribution system.

22. With a neat diagram, explain the complete a.c. system for distribution of electrical energy.

23. Describe briefly the different types of d.c. distributors.

24. What are the advantages of a doubly fed distributor over singly fed distributor?

25. Derive an expression for the voltage drop for a uniformly loaded distributor fed at one end.

26. What is the purpose of interconnector in a d.c. ring main distributor?

27. Explain 3-wire d.c. system of distribution of electrical power.

28. What are the advantages of 3-wire distribution over 2-wire distribution.

29. Explain the use of rotary balancer in a 3-wire d.c. distribution system.

30. What is a booster? With a neat diagram, explain how it can be used on a feeder.

31. Show with a neat diagram how unbalanced loads in a 3-wire d.c. system cause unequal voltages on the two sides of the neutral.

32. Write short notes on the following : i. Ring main distributorii. Current distribution in a 3-wire d.c. systemiii. Balancers

33. What is the importance of minimum potential on the distributor?

34. Why is 3-wire d.c. distribution preferred to 2-wire d.c. distribution?

35. Which points of d.c. ring main should be connected through interconnector?

36. Can we use compound generator as a booster?37. Why do we use a balancer set?

38. Can exact balance of voltages to obtained with a balancer set?

39. How does a.c. distribution differ from d.c. distribution?

40. What is the importance of load power factors in a.c. distribution?

UNIT – IV

1. a. Derive an expression for voltage drop and power loss for uniformly radial type distribution load.b. A 3 phase distribution line has resistance and reactance per phase of 15 ohm and 20 ohms respectively.

If the sending end voltage is 33 Kv and regulation of the line is not to exceed 10 %. Find the maximum power in Kw which can be transmitted over the line. Find also the KVAR supplied by the line when delivering the maximum power. (JNTU May 09)

2. a. Explain single phase two wire unigrounded levels to calculate voltage drop and power loss.b. Consider three phase three wire 240 V secondary system with balanced laods at A,B and C. Determine

the following:i. Calculate the total voltage drop

ii. calculate real power per phase for each loadiii. Reactive power per phaseiv. KVA o/p and load power factor of distribution transformer. (JNTU May 09)

3. a. Derive the voltage drop equation for anon uniform distributed load. (JNTU May 09)b. A single phase feeder circuit has total impedance of (1+j3)Ω and VR = 2400∟00V and Ir = 500∟-300,

respectively. Find i. Power factor of the load ii. Load P.F. for which the drop is maximum.

4. a. Derive an expression for voltage drop in a three phase ac distributor. (JNTU May 09)b. Electrical energy is supplied to a consumer from a substation at a distance of 250m.If the power

required by the consumer is three phase 100KW at 415 v unity pf and resistance of single conductor of the connecting cable is 0.1/1000Ω/m,calculate. i. the voltage at the bus bar of the substation ii. the power lossi nthe cable.

5. a. Prove the power loss due to the load currents in the conductors of single-phase lateral ungrounded neutral case is 2 times large than one in the equivalent three phase lateral.

b. Prove the power loss due to load currents in the conductors of the single-phase two-wire ungrounded lateral with full capacity neutral is 6 times large than the one in the equivalent three phase –wire lateral.

(JNTU Nov 08, 07, 05)

6. Consider the single phase radial distributor shown in the following figure 5

The magnitude of load currents, p.f.s and distances are indicated in the figure. The resistance and reactance of each wire are 0.1 ohm and 0.2 ohms per km respectively. It is required to maintain voltage at point B as 230 00 Volts, find

a. Voltage drop in the three sectionsb. Total voltage drop in the feederc. supply voltage, current and power factord. KVA output of supply

The p.f. angles of individual loads are w.r.t. voltage at point B. (JNTU May 09, Nov 08, 05, Mar 06)

7. a. In terms of resistance and reactance of the circuit, derive the equation for load power factor for which voltage drop is minimum.

b. An unbalanced 3-phase star connected load is connected to a balanced 3-phase, 4-wire source. The load impedances ZR, ZY, and ZB are given as, 70 300, 85 -400 and 50 350 ohms per phase respectively and the phase ‘R’ line voltage has an effective value of 13.8 KV. Use the line to neutral voltage of phase ‘R’ as the reference and determine the line and neutral currents and total real and reactive powers. (JNTU Nov 08, Mar 06)

8. a. Prove the power loss due to load currents in the conductors of the 2-phase, 3 wire lateral with multi-grounded neutral is approximately 1.64 times larger than the one in the equivalent 3-phase lateral.

b. Consider the three phase, 3 wire 240V secondary system with balanced loads at A, B and C as shown in figure Determine:

i. The voltage drop in one phase of lateralii. The real power per phase for each loadiii. The reactive power per phase for each load. (JNTU May 09, Nov 08, 05)

9. A 1-Φ feeder circuit has total impedance (1+j3) ohms, receiving end voltage is 11kV and current is 50∟-300 A. Determine:

a. p.f. of load b. load p.f. for which the drop is maximumc. load p.f. for which impedance angle is maximum and derive the formula used. (JNTU Nov 08)

10. a. Write about non - three phase primary lines.b. Consider the 3 - phase, 3 wire 240 V secondary system with balanced loads at A, B and C as shown in

figure. Determine the following:

i. Calculate the total voltage dropii. Calculate the kVA output and load p.f. of the distribution transformeriii. Calculate total power per phase for each load. (JNTU Nov 08)

11. Derive an approximate voltage drop & power loss equation of primary feeder and give the condition for load p.f. at which voltage drop is maximum. (JNTU Nov 08)

12. a. Derive an approximate voltage-drop equation of primary feeder and give the condition for load power factor at which voltage drop is maximum

b. Consider a single-phase, 2-wire secondary distributor of length ‘I’ meters from the distribution transformer. At a length of ‘l1’ meters from source, a load of ‘I1’ amps with a p.f. of cos Φ1 (lag) is tapped. At a length of ‘l2’ meters from first load, a second load of I2 amps with a power factor cos Φ2

(lead) is taped. At a length of ‘l3’ meters from second load, a third load of ‘I2’ amps with a UPF is

tapped. If resistance and reactance and reactance of each wire are r and x ohms/meter respectively, derive approximate voltage drop equation in the distributor. (JNTU Nov 07)

13. a. What are the different types of manual methods used for the solution of radial networks and explain in detail.

b. Write about non-three phase primary lines. (JNTU Jan 04)

14. Compare the 3-phase balanced wire with unbalanced wires in i. 1-phase ungrounded ii. Line-line ungrounded iii. Line-ground system. Derive the voltage drop & power loss equations. (JNTU Dec 03)

15. a. Explain various factors affecting the primary feeder voltage levels?b. Explain the uniformly loaded radial feeder? Give the equation for voltage drop & power loss in terms

of feeder length. (JNTU Oct 03)16. a. Derive the equation for the voltage drop and power loss for the radial feeder with uniformly distributed

load. (JNTU Mar 03)b. compare the 3-phase balanced network with 1-phase two-wire with uni-grounded neutral laterals.

17. a. Derive the equation for the voltage drop and power loss for the radial feeders with non-uniformly distributed load.

b. Explain the different fault that occurs in distribution system. (JNTU Mar 03)

18. a. Derive the equation for voltage drop and power loss when a radial feeder is having non-uniformly distributed load. (JNTU Apr 03)

b. What are the different non e-phase primary lines considered for distribution system.

19. a. Explain the difference between a 3-phase balanced and non 3-phase primary lines.b. A 3-phase radial feeder has receiving end voltage of 33.0 KV (L-L) and total impedance of (5.25+j

10.95) ohms/phase of a load of 5 MW with a lagging power factor of 0.85 is supplied. Determine he sewing end phase and lien voltages and the load angle.

20. What is a sub-station? Name the factors that should be taken care of while designing and erecting a substation.

21. Discuss the different ways of classifying the sub-stations.

22. Give comparison of outdoor and indoor sub-stations.

23. What is a transformer sub-station? What are the different types of transformer sub-stations? Illustrate your answer with a suitable block diagram.

24. Draw the layout the schematic connection of a pole-mounted sub-station.

25. Draw the layout of a typical underground sub-station.

26. Write a short note on the sub-station equipment.

27. What are the different types of bus-bar arrangements used in sub-stations? Illustrate your answer with suitable diagrams.

28. What are terminal and through sub-stations? What is their purpose in the power system?

29. Draw the key diagram of typical 66/11 KV sub-station.

30. Draw the key diagram of a typical 11 KV / 400 V indoor sub-station.

31. What is the need of a sub-station in the power system?

32. Why are pole-mounted sub-stations very popular?

33. Where we erect a terminal sub-station?

34. Why do we use isolators on both sides of circuit breaker?

35. What is the utility of instrument transformers in sub-stations.

UNIT – V

1. a. What are the different types of common faults that occur in a distribution system? Explain them with proper line diagram.

b. Explain the principle of operation of fuses. (JNTU May 09)

2. a. Explain the significance of fuse in protecting the distribution system.b. Explain the procedure for general coordination. (JNTU May 09)

3. a. What are Automatic line sectionalizers? Explain the purpose and advantages of using them?b. What is the main objective of Distribution system protection? Explain in detail. (JNTU May 09)

4. a. What are the objectives of distribution system protection. (JNTU May 09)b. Explain in detail about line sectionalizers.c. Explain the principle of operation of circuit breakers employed for distribution systems.

5. a. What are the main objectives of distribution protection? Discuss.b. The per unit values of positive, negative and zero sequence reactance’s of a network at fault are 0.08,

0.07 and 0.05 respectively. Determine the fault current if the fault is double line to ground. (JNTU May 09, Nov 08, 05, Mar 06)

6. a. Explain the principle of operation of line sectionalizer. b. Explain the coordination procedure between fuse and circuit breaker. (JNTU May 09)

7. a. What are the types of common faults that occur in a distribution system?b. Considering a typical example, describe the procedure for fault current calculations in a distribution

system, mentioning the assumptions to be made for the analysis. (JNTU May 09)

8. a. What are the objectives of Distribution system protection.b. Explain about the operation of a Fuse. (JNTU Nov 08)

9. Describe the principle of operation of: (JNTU Nov 08)a. Fuses b. Circuit Breakers c. Line Sectionalizer d. Circuit Recloser.

10. a. Discuss the procedure for fault current calculation in following faults:i. 3-phase fault. ii. Single Line-Ground fault (JNTU Nov 08)

b. Explain about the operation of a circuit breaker.

11. a. What are the objectives of Distribution system protection.b. What are the advantages and disadvantages of fuses. (JNTU Nov 08)

12. Explain the principle of operation of circuit Reclosure (JNTU Nov 07)

13. a. What are the main objectives of distribution protection? Discuss. (JNTU Nov 07, Mar 06)b. The per unit values of positive, negative and zero sequence reactances of a network at fault are 0.08,

0.07 and 0.05 respectively. Determine the fault current if the fault is double line to ground.

14. a. What are the types of common faults that occur in a distribution system? Explain them with proper line diagram

b. Considering a typical example, describe the procedure for fault current calculations in a distribution system mentioning the assumptions to be made for the analysis. (JNTU Nov 05)

15. Explain the principle of operation of fuse. (JNTU Nov 05)

16. a. Write in detail about the operation of the line sectionaliser.b. What are the objectives of distribution system protection?c. Explain about general coordination procedure. (JNTU Jan 04)

17. Explain the different types of faults in distribution system occurs. Derive necessary equations. (JNTU Dec 03)

18. a. Explain the objectives of distribution system protection.b. Explain about the coordination of protective devices. (JNTU Mar 03)

19. Discuss the different types of bus-bar arrangements

20. a. Discuss the various common faults that occur in a distribution system.b. Explain the working of a line sectionalizer.c. Explain briefly the necessity of coordination of projection devices in a distribution system.

21. What is the difference betweeni. a switch and circuit ii. A fuse and circuit breaker?

22. Explain the various methods of accommodating high-voltage switchgear.

23. What are the limitations of a fuse?

24. Why do we use C.T. in the relay circuit?

25. What is the necessity of bus-bar?

26. Why do we use isolators on both sides of the circuit breaker?

27. Why are isolators not opened on load?

28. Which faults ___________ symmetrical of unsymmetrical ________ are more frequency in power system and why?

29. Suddenly a circuit carries a current 20 times the normal current. Is there possibility of short-circuit or overload?

30. What is a 3-phase unsymmetrical fault? Discuss the different types of unsymmetrical faults that cn occur on a 3-phase system.

31. Discuss the ‘symmetrical components method’ to analyse an unbalanced 3-phase system.

32. Express unbalanced phase currents in a 3-phase system in terms of symmetrical components.

33. What do you understand by positive, negative and zero sequence impedances? Discuss them with reference to synchronous generators, transformers and transmission lines.

34. Derive an expression for fault current for single line-to-line fault by symmetrical components method.

35. What do you understand by sequence networks? What is their importance in unsymmetrical fault calculations?

36. Write short notes on the following : i. Positive sequence networkii. Negative sequence networkiii. Zero sequence network.

37. Why is 3 phase symmetrical fault more severe than a 3 phase unsymmetrical fault?

38. Do the sequence components physically exist in a 3-phase system?

39. Why do we prefer to analyse unsymmetrical faults by symmetrical components method?

40. The positive sequence network of a power system is similar to the negative sequence network. What do you infer form it.

UNIT – VI

1. a. Explain the principle of operation of line sectionalizers.b. Discuss briefly the general coordination procedure. (JNTU May 09)

2. a. Explain briefly secondary system fault current calculation fori. single phase 120/240V three wire secondary serviceii. Three phase 240/120 star/delta or delta/delta four wire secondary.

b. Explain the fault calculations involved in the following type of faults.i. Three phase grounded or ungrounded fault.ii. Phase to phase grounded fault. (JNTU May 09)

3. a. Explain in detail how the coordination of various protective devices helps in improving system performance. (JNTU May 09)

b. List out the fault calculations involved in any two types of faults which occur in distribution System.

4. a. What is the need for coordination ? Explain in detail. (JNTU May 09)b. Explain the overall coordination procedure employed for protection of distribution systems.

5. a. Explain the principle of operation of line sectionalizer.b. Explain the coordination procedure between fuse and circuit breaker. (JNTU Nov 08, Mar 06)

6. a. What are the over current protective devices applied to distribution systems? Explain any one. b. Explain the salient points in general co-ordination procedure. (JNTU Nov 08)

7. a. Explain Fuse-Fuse coordination.b. Explain Fuse-Recloser coordination. (JNTU Nov 08)

8. a. What is the data required for the general coordination procedure?b. Explain Fuse-Fuse coordination. (JNTU Nov 08)

9. Explain the coordination procedure between two fuses. (JNTU Nov 07, 05)

10. a. Discuss about the principle of operation of fuses and circuit reclosures.b. What is the necessity of improving distribution systems and what are remedial measures used in the

distribution systems. (JNTU Jan 04)

11. What is meant by co-ordination in protecting devices? Give the necessity? Explain the co-ordination between i. Fuse-to-fuse ii. Fuse-to- Recloser operation. (JNTU Dec 03)

12. Explain the co-ordination procedure among the following : a. Fuse to circuit breaker b. Fuse to Fuse (JNTU Jun 02)

13. a. Explain the principle of operation of circuit reclosures and line sectionalizer (JNTU Jun 02)b. Explain line drop compensator.

14. Explain the following protective devices in detail. (JNTU Apr 03)a. Fuse b. Circuit Breaken c. Automatic Circuit Reclosere d. Automatic line sectionalize

15. a. Explain the coordination procedure between two fusesb. Explain the coordination procedure between reclosure fuse. (JNTU Apr 03)

16. Explain about Automatic Circuit Relcosers.

17. Explain about Automatic Line sectionalizers.

18. Explain about Automatic Circuit Breakers .

19. What is the objective of Distribution System Protection

20. Explain about coordination of protective devices.

21. Explain about Fuse-to-Fuse coordination.

22. Explain about Recloser - to - recolser coordination.

23. Explain about Recloser – to – fuse coordination.

24. Explain about Recloser to substation transformer high voltage side fuse coordination.

25. Explain about fuse-to-circuit breaker coordination.

26. Explain about recloser-to-circuit breaker coordination.

27. Explain about circuit breaker-to-circuit breaker coordination.

28. Explain about circuit breaker-to-sectionalizer coordination.

29. Explain about fuse-to-secionalizer coordination.

30. Explain about secionalizer-to-sectionalizer coordination.

UNIT – VII

1. a. Explain the computerized method to determine the economic power factor. b. A feeder supplies an industrial consumer with a cumulative load of

i. Induction motor totaling 200HP which runs at an average efficiency of 89% and a lagging average p.f. of 0.85.ii. Synchronous motors totaling 100HP with an average efficiency of 85% and iii. a heating load of 100kW. The industrial consumer plans to use the synchronous motors to correct its overall power factor. Determine the required p.f. of the synchronous motors to correct the overall p.f. at peak load to a. Unity b. 0.95 lag (JNTU May 09)

2. a. Write short notes on comparisons of series and shunt compensation.b. How do you determine the best capacitor location? Explain. (JNTU May 09)

3. a. Explain the practical procedure to determine best capacitor location. (JNTU May 09)b. Verify that the loss reduction with two capacitors bank is

4. a. Write short notes on power factor correction.b. Explain the practical procedure to determine the Best Capacitor Location. (JNTU May 09)

5. a. What are the effects of shunt and series capacitors in distributions systems?b. Explain the procedure employed to determine the best capacitor location. (JNTU May 09)

a. Explain the effect of shunt compensation on distribution system.b. a 3-phase substation transformer has a name plate rating of 7250 KVA and a thermal capability of

120% of the name plate rating. If the connected load is 8816 KVA with a 0.85 pf lagging p.f. determine the following. i. The KVAR rating of the shunt capacitor bank required to decrease the KVA load of the

transformer to its capability level. ii. The power factor of the corrected level. (JNTU May 09, Nov 07)

6. A 3-phase transformer rated 7000 KVA has a over load capability of 125% of the rating. If the connected load is 1150KVA with a 0.8 pf (lag), determine the following :

a. The KVAR rating of shunt capacitor bank required to decrease the KVA load of the transformer to its capability level (JNTU May 09, Nov 08, 05, Mar 06)

b. The p.f. of the corrected levelc. The KVAR rating of the shunt capacitor bank required to correct the load p.f. to unity.

7. Write detailed notes on the following:a. Loss reduction due to capacitor compensation.b. With the help of a phasor diagram, show how a series capacitor boosts the voltage? What are the

drawbacks of this method? (JNTU Nov 08)

8. a. Write notes on need for maintaining good voltage profile in power systems and need to improve power factor.

b. 3-Phase, 500H.P, 50Hz, 11KV star connected induction motor has a full load efficiency of 85% at lagging p.f of 0.75and is connected to a feeder. If it is desired to correct the p.f of 0.9 lagging load, determine the:i. The size of the capacitor bank in KVAR. (JNTU Nov 08)ii. The capacitance of each unit if the capacitors are connect in delta as well as star.

9. a. Write notes on loss an over excited synchronous machine improves power factor?b. A feeder supplies an industrial consumer with a cumulative load of

i. Induction Motors totaling 300HP which runs at an average efficiency of 89% and lagging average p.f. of 0.85

ii. Synchronous Motors totaling 100HP with an average efficiency of iii. A heating load of 100 KW. The industrial consumer plans to use the synchronous motors to correct is overall p.f. Determine the required p.f. of the synchronous motors to correct the overall p.f. at peak load to a. unity b. 0.96 lagging. (JNTU Mar 06, Nov 05)

10. a. Compare and explain the role of shunt and series capacitors in P.F. correction.b. A 400V, 50 cycles three phase line delivers 207 KW at 0.8 p.f. (Lag). It is desired to bring the line p.f.

to unity by installing shunt capacitors. Calculate the capacitance if they are i. Star connected ii. Delta connected (JNTU Nov 05)

Explain the computerized method to determine the economic power factor. (JNTU Nov 05)

11. a. What procedure implemented for determining the best capacitor location.b. What is the effect of shunt capacitors in power factor control? (JNTU Jan 04)

12. Assume that a 2400V single-phase circuit feeds a load of 360kW measured by a wattmeter at a lagging load factor and the load current is 200A. if it is desired to improve the power factor. Determine the following :

13. a. The uncorrected power factor and reactive load.b. The new corrected power factor after installing a shunt capacitor bank with a rating of 300 KVAR.

(JNTU Dec 03)

14. a. Explain the necessity of shunt & series capacitors in distribution system with phasor diagram.b. Explain the switched & fixed capacitors operation in D.S. (JNTU Dec 03)

15. Give optimal procedure for capacitor installation.a. Assume that a three phase 400-HP, 60 Hz, 4160V wye-connected induction motor has a full-load

efficiency of 90 percent, a logging power factor of 0.75 and is connected to a feeder. If it is desired to correct the power factor of the load to a lagging power factor of 0.92 by connecting three capacitors a the load, determine the following:

b. The rating of the capacitor bank in kilowatts.c. The capacitance of each unit if the capacitors are connected in delta, it microfarads.d. The capacitance of each unit if the capacitors are connected in wye in microfarads. (JNTU Dec 03)

16. Explain time series approach of forecasting. (JNTU Jun 02)

17. a. Write the steps in time series analysis. b. Explain the effect of series capacitor. (JNTU Jun 02)

18. a. Write step-in-selecting the optimal location of capacitor.b. Write short notes on calculation of voltage dip due to motor starting. (JNTU Jun 02)

19. Assume that 500 HP, 50Hz, 3300 V Wye connected induction motor has a full load efficiency of 88% a lagging pf of 0.30 and is connected to a feeder. If it is desired to correct the pf of C.S. by connecting three capacitors at the load. Determine the following:

a. The rating of the capacitor bank, in VARb. The capacitance of each unit if the capacitors are connected in delta. c. The capacitance of each unit of the capacitors are connected ion star. (JNTU Jun 02)

20. a. Explain in detail the effect of shunt and series capacitors in distribution system. (JNTU Apr 03)b. List out the Economic benefits obtained because of the optimal location of capacitors.

21. Why is there phase difference between voltage and current in an a.c. circuit? Explain the concept of the power factor.

22. Discuss the disadvantages of a lower power factor.

23. Explain the causes of low power factor of the supply system.

24. Discuss the various methods for power factor improvement.

25. Derive an expression for the most economical value of power factor which may be attained by a consumer.

26. Show that the economical limit to which the power factor of a load can be raised is independent of the original value of power factor when the tariff consists of a fixed charge per kVA of maximum demand plus a flat rate per kWh.

27. Write short notes on the following : i. Power factor improvement by synchronous condenser. ii. Importance of p.f. improvementiii. Economics of p.f. improvement.

28. what is the importance of power factor in the supply system?

29. Why is the power factor not more than unity?

30. What is the effect of low power factor on the generating stations?

31. Why is unity power factor not the most economical p.f.?

32. Why a consumer having low power factor is charged at a higher rates.

33. What are the effects of series and shunt capacitors.

34. What are the applications of capacitors.

35. Explain Economic justification for capacitors.

36. Explain practical procedure to determine the best capacitor location.

37. Explain a mathematical procedure to determine the optimum capacitor allocation.

38. What are the power capacitors.

39. Explain capacitor tank rupture considerations.

40. Explain dynamic behavior of distribution systems.

UNIT – VIII

1. a. How an AVB can control voltage? With the aid of suitable diagram explain its function.b. Briefly write the various methods adopted for voltage control. (JNTU May 09)

2. Write short notes on: (JNTU May 09)a. Power factor correction b. Effect of AVB/AVR c. Line drop compensation

3. a. What are various ways to improve the overall voltage regulation. (JNTU May 09)b. Explain the methods to calculate the voltage dips due to voltage fluctuations in distribution systems.

4. a. How an AVR can control voltage? With the aid of suitable diagram explain its function.b. Briefly explain about line drop compensation. (JNTU May 09)

5. a. Write a short notes on any two methods of voltage control?b. “Voltage Control and p.f. correction why are they necessary in power systems? What are the

disadvantages of low voltage and low p.f. of the system?(JNTU May 09, Nov 08, 07, 05, Mar 06)

6. a. Briefly explain the line drop compensation and voltage control. (JNTU Nov 08, 05)b. How an AVB can control voltage? With the aid of suitable diagram explain its Function.

7. a. Write short notes on any two methods of voltage control?b. Voltage control and p.f. correction are necessary in power systems? Explain. What are the

disadvantages of low voltage and low p.f. of the system? (JNTU Nov 08, Mar 06)

8. a. Briefly explain the line drop compensation on voltage control. (JNTU Nov 08)b. Write the ways to improve the distribution system overall voltage regulation?

9. a. Why we need to control the voltage of power system? Explain in detail.b. Compare and explain the role of shunt and series capacitor in voltage control.

(JNTU May 09, Nov 07, 05, Mar 06)

10. a. How do the shunt capacitor and reactors control the voltage? List the disadvantages of using a shunt capacitor for voltage control.

b. With the help of a phasor diagram, show how a series capacitor boosts the voltage? What are the drawbacks of this method? (JNTU Nov 05)

11. Write a short notes on the following:a. Modern lightening arrestersb. Radial and loop type of primary feeders.c. Types of power capacitors. (JNTU Jan 04)

12. Explain i. Line-drop Competition ii. Voltage Fluctuation iii. AVR/AVB (JNTU Dec 03)

13. a. Explain the line drop compensation with neat diagram.b. Explain the Radial and Loop type primary feeders. (JNTU Apr 03)

14. Discuss the importance of voltage control in the modern power system.

15. What re the various methods of voltage control in a power systems

16. Describe with the aid of neat sketch the construction and working of a Tirril regultor.

17. Explain the construction and working of Brown-Boveri regulator with a neat sketch.

18. Describe the off-load tap changing transformer method of voltage control. What are the limitations of the method?

19. Explain with a neat sketch:

i. on-load tap-changing transformer ii. Auto transformer tap-changing

20. What do you understand by induction regulators? Describe single phase and three phase inductance regulators.

21. Describe the synchronous condenser method of voltage control for a transmission line. Illustrate your answer with a vector diagram.

22. Voltage control equipment is generally located at more than one point. Why?

23. Tap-changing is generally performed on load. Why?

24. Why do we use overshooting the mark principle in automatic voltage regulators?

25. Explain about quality of service and voltage standards.

26. Explain about voltage control.

27. Explain about feeder voltage regulators.

28. Explain about line drop compensation

29. Explain about voltage fluctuations.

30. What are the limitations of voltage control.


The main objective of this lab is to make students to get lot of knowledge in circuit simulation and synthesis. It can be a good guide for real time implementation of any project or circuit ideas. The approach taken in each experiment is started with the basic theory of circuit model and the necessary data. The circuit is simulated for various time/frequency responses. This lab deals equally the basic philosophy of building systems for both the power engineer and signal engineer. It covers most of the modeling of basic electrical and electronics circuits, power system and control system problems.

6.2.2 SCOPEAutomation of industries is growing since the advent of microprocessors. To meet this rapid growth one has to be conversant with programming and simulation of the system problem. By doing this lab course one could look him/her as research and development engineer, moreover simulation is very much needed to know many pros and cons of implementing any control or design idea.

At the minimal the scope is laid in doing many research projects in their academics or even sponsored.

6.2.3 PREREQUISITES

A basic knowledge about the following subjects is required.

Network theory, Control systems, Power Electronics, Computer Methods in Power Systems, LDIC and Power System Modelling and Analysis Computer proficiency in Microsoft windows and ‘C’ language also required.

PREAMBLE

This lab covers the experiments in Network theory, Control systems, Power Electronics and Computer Methods in Power Systems subjects. The JNTU has given the following experiments in the syllabus. The students are advised to go through the theory part in the mentioned suggested books.

6.2.4 SYLLABUS – JNTU

EXPERIMENT NO. 1Pspice simulation of transient response of RLC circuits.i. Response to Pulse inputii. Response to step inputiii. Response to sinusoidal input (JNTU Sl.No.1)

OBJECTIVEThe objective is to study the operation and characteristics of R-L-C series circuit for a different input signals

PREREQUISITESKnowledge on transient response of 1st and 2nd order RLC circuits for various sources

DESCRIPTIONi. Introduction to Experiment-30 minii. Writing program for given circuitiii. Simulation of the circuit with PSPICEiv. Experimental determination of the output voltage waveforms across different components in the circuit for various inputs and their variation with time.

APPLICATIONSThe analysis of different types of test signals is used in control systems analysis and design to know the performance of the any systems.

EXPERIMENT NO. 2

Analysis of three-phase circuit representing the generator transmission line and load. Plot three phase currents & neutral current using PSPICE. (JNTU Sl.No.2)

OBJECTIVE To analyse the 3-phase circuit representing generation, transmission & load and to plot 3-phase currents and neutral current for balanced and unbalanced loads.

PREREQUISITESKnowledge on balanced and unbalanced 3-phase systems and generator modelling subject to requirement.

DESCRIPTIONi. Introduction to Experiment-30 minii. Writing program for given circuitiii. Simulation of the circuit with PSPICEiv. Observation and analysis of 3 phase currents and neutral current for a balanced and unbalanced loads for a forgiven range of cycles

APPLICATIONSThe analysis of balanced and unbalanced loads with 3-phase supply is used for finding 3-phase power and power factor in each phase.

EXPERIMENT NO. 3 APspice simulation of single-phase full converter using RL & E load

OBJECTIVE

The objective is to study the output waveforms of single phase full-converter using thyristors at various load conditions.

PREREQUISITES1-phase Full converter-operational principal, Waveforms, Expression for average value of output for RL & E Loads

DESCRIPTIONi. Introduction to Experiment-30 minii. The critical calculationsiii. Writing program for given circuitiv. Simulation of the circuit with PSPICEv. Observation and analysis the output of rectifier and inverter operations for delay angle less than 90

degrees and greater than 90 degrees respectively.

APPLICATIONSDesign and testing of the single-phase full-wave controlled rectifier which is used to control power flow in many applications (e.g., power supplies, variable-speed dc motor drives, and input stages of other converters)

EXPERIMENT NO. 3B

Pspice simulation of single-phase AC voltage controller using RL & E loads. (JNTU Sl.No.3)

OBJECTIVE The objective is to analyse the operation of single phase AC voltage controller with RL& E loads and plot the output voltages at different load conditions

PREREQUISITESSingle-phase AC voltage controller operational principal, Waveforms, Expression for average value of output for RL & E loads

DESCRIPTIONi. Introduction to Experiment-30 minii. Theoretical calculationsiii. Writing program for given circuitiv. Simulation of the circuit with PSPICEv. Observation and analysis of the output voltage at different load conditions

APPLICATIONSDesign and testing of the AC voltage controllers which are used for domestic and industrial heating, transformer tap changing, lighting control, speed control of single phase and 3 phase AC devices and starting of induction motors.

EXPERIMENT NO. 4Pspice simulation of DC circuit for determining Thevenin’s equivalent

OBJECTIVEThe objective is to write a PSPICE program to find the thevenin’s equivalent for a given circuit.

PREREQUISITESKnowledge on KCL, KVL and theoretical calculations of thevenin’s theorem.

DESCRIPTIONi. Introduction to Experiment-30 minii. Theoretical calculationsiii. Writing program for given circuitiv. Simulation of the circuit with PSPICEv. Comparison between theoretical results and practical results

APPLICATIONSi. It is used to find out the equivalent resistance between any two nodes and voltage across the load for complicated networksii. It is used to find power dissipation in electrical networks

EXPERIMENT NO. 5 APspice simulation of Resonant pulse commutation circuit (JNTU Sl.No.4)

OBJECTIVE The objective is to study and analyse the working of resonant pulse commutation circuit for the given load conditions.

PREREQUISITESKnowledge on Resonant pulse commutation circuit operating principle, output wave forms.

DESCRIPTIONi. Introduction to Experiment-30 minii. Theoretical calculationsiii. Writing program for given circuitiv. Simulation of the circuit with PSPICEv. Observation and analysis of the capacitor voltage, capacitor current and load currentvi. Experimental determination of turn-off time.

APPLICATIONSDesign and testing of Resonant pulse commutation circuit which is used to turnoff the thyristor by forced commutation principle in various power electronic based systems

EXPERIMENT NO. 5BPspice simulation of Buck chopper

OBJECTIVE The objective is to study and analyze the operation of buck chopper for required load conditions.

PREREQUISITESKnowledge on buck chopper operating principle, output wave forms and design

DESCRIPTIONi. Introduction to Experiment-30 minii. Theoretical calculations

iii. Writing program for given circuitiv. Simulation of the circuit with PSPICEv. Observation and analysis of the Capacitor Voltage, Load Current, and Filter currentvi. Experimental determination fourier coefficients of the input currents

APPLICATIONSDesign and testing of DC/DC chopper which are used in high voltage DC transmission system. These are used where the DC regulated supply is required.

EXPERIMENT NO. 6Pspice simulation of single phase Inverter with PWM control. (JNTU Sl.No5)

OBJECTIVE The objective is to study and analyse the operation of single phase inverter with PWM control

PREREQUISITESKnowledge on single phase Inverter with PWM control operating principle, output wave forms.

DESCRIPTIONi. Introduction to Experiment-30 minii. The critical calculationsiii. Writing program for given circuitiv. Simulation of the circuit with PSPICEv. Observation and analysis Output voltage waveforms and Fourier Coefficients of output voltage

APPLICATIONSDesign and testing of the single-phase full-bridge inverter which is used to control power flow in any applications (e.g., ac and dc power supplies, and input stages of other converters)

EXPERIMENT No. 7Pspice simulation of OP AMP Based Integrator & Differentiator circuits

OBJECTIVEThe objective is to study the operation of OP AMP Based Integrator & Differentiator circuits

PREREQUISITESKnowledge of OP AMP Based Integrator & Differentiator

DESCRIPTIONi. Introduction to Experiment-30 minii. Writing program for given circuitiii. Simulation of the circuit with PSPICEiv. Experimental determination of the output voltage waveforms across different components in the circuit

for various inputs and their variation with time.

APPLICATIONS : 1. Differentiator and integrators are used in PI, PD and PID controllers2. Integrators are used in delta modulation circuit in digital communications3. Integrators are used in A/D converters.

EXPERIMENT No. 8Circuit analysis using MATLAB

OBJECTIVE: The objective is to study the operation of given circuit

PREREQUISTE:Knowledge of Matlab And Series RLC Circuit

DESCRIPTION: Explaining the program

Designing the circuitSimulating the circuitVerifying the results.

APPLICATION1. To analyze the performance of different converters without using hardware setup.2. To understand the design concept of converter circuits.3. To design suitable filter circuit for the different kind of loads.4. The behavior of the converter circuit for R, RL and RLC circuits.

EXPERIMENT No. 9Simulation of Dynamical System (Single area and two area power system)

OBJECTIVE: The objective is to study the dynamic behavior of single area and two area system using MATLAB Simulink toolbox.

PREREQUSITE: Knowledge of single area and two area power systems

DESCRIPTION : Explaining the program Using simulink designing the circuit Simulating verifying the results.

APPLICATION:To observe change in frequency as function of the time for a step change in load

EXPERIMENT No.10Stability Analysis (Bode, Root Locus, Nyquist Plot) of LTI System Using MATLAB

OBJECTIVE: The objective is to determine the stability of a given system upto 5th order by plotting root locus, bode plot and nyquist plot using MATLAB.

PREREQUSITE: Knowledge of bode, root locus, nyquist plot

DESCRIPTION :

Explaining the program Writing the program Simulating verifying the results.

APPLICATIONS

Root locus technique is used to find the stability of system in time domain analysis. Bode and nyquist techniques are used to find stability of the system in frequency domain. All these methods are applicable for linear systems only.

EXPERIMENT NO.11Linear System Analysis (Time Domain Analysis, Error Analysis) Using MATLAB

OBJECTIVE: The objective is to find the time domain analysis of a system using MATLAB

PREREQUISITE: Knowledge on TIME DOMAIN ANALYSIS

DESCRIPTION : Explaining the program Debug and run the program

Analyze the time response obtained.

APPLICATIONS :Transfer function analysis used to find the performance analysis of physical systems e.g., Generators, Motors, and many more which has been using in electrical and electronics application.

EXPERIMENT NO. 12Transfer Function Analysis Of A Given Circuit Using Matlab

OBJECTIVE: The objective is to carry out transfer function analysis of the given electrical circuit using MATLAB.

PREREQUISITE: Knowledge on transfer function

DESCRIPTION : Explaining the program Writing the transfer function Simulating the transfer functionVerifying the results.

APPLICATION :The transfer function analysis is used to find the stability of system in time domain analysis. All the methods are applicable for linear systems only.


1. Pspice for circuits and electronics using PSPICE, M.H. Rashid, M/s. PHI Publications.2. Pspice A/D user’s manual, Microsim, USA.3. Pspice reference guide, Microsim, USA.4. Power Electronics ,Circuits, Devices and Applications, M.H. Rashid, 2nd Edn., M/s. PHI Private

Limited.5 Power System Analysis, Hadi Saadat,Tata Mc- Graw Hill Edition6. Modern Power System Analysis, I.J. Nagrath and D.P. Kothari, 2nd Edn.,Tata MGraw – Hill

Publishing Company Ltd.7. MATLAB user’s manual, Mathworks, USA.8. MATLAB, Control System tool box, Mathworks, USA.9. SIMULINK user’s manual, Mathworks, USA.10. EMTP User’s Manual.


REGIONAL1. Name : V.T. Somashekhar

Designation : Asst. Prof. Department : Department of Electrical EngineeringOffice Address : NIT, Warangal – 506004Phone Number : 0870-245416Email : [email protected]

2. Name : Dr. Bhagwan K.MurthyDesignation : Assoc. ProfessorDepartment : Department of Electrical EngineeringOffice Address : NIT, Warangal – 506004Phone Number : 0870-2431616Email : [email protected]

3. Name : Dr. M.Vijay KumarDesignation : Assoc. ProfessorDepartment : Dept. of Electrical Engg.Office Address : JNTU College of Engg., Ananthapur, A.P.Phone Number :Email : [email protected]

4. Name : Prof. DhanvanthriDesignation : Head of EEE DepartmentDepartment : EEE DepartmentOffice Address : Bharat Engg. College, HyderabadPhone Number : 9849052608Email :

5. Name : Prof. A.D.RajkumarDesignation : ProfessorDepartment : Electrical Engineering DepartmentOffice Address : University College of Engineering, Osmania University-500007Phone Number : 040-27682382.Email :

NATIONAL

1. Name : Prof. S.S. MurthyDesignation : ProfessorDepartment : Electrical Engineering DepartmentOffice Address : Room.No.II/235a, IIT Delhi, Houszkhas, DELHIPhone Number : 1112659663Email : [email protected]

2. Name : Prof. T.K.BhattacharyaDesignation : Associate ProfessorDepartment : Dept. of Electrical Engg,Office Address : IIT, Kharagpur-721302Phone Number : 91-3222-283040Email : [email protected],

INTERNATIONAL

1. Name : Prof. Ramakrishna GokarajuDesignation : ProfessorDepartment : Dept. of Elec.Engg.,Office Address : Room 3B33, 57, campus Drive, Saskatchewan, S7N5A9, Canada,Phone Number : 306-906-5385Email : [email protected].

2. Name : Ernet. A.MendrelaDesignation : Professor

Department : Dept. of Elect& computer Engg.,Office Address : Luisiana state University, Baton Range,LA70803-5901Phone Number : 225-578-5239

Documents

4EEE-09-10-1 sem