EDS Handout

8/12/2019 EDS Handout

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HANDOUT

ACADEMIC YEAR: 2012-2013

ELECTRICAL DISTRIBUTION SYSTEMS

CLASS : IV B.TECH-I SEM

NAME OF THE STAFF MEMBER: Mrs K.LALITHA, Asst.Prof., EEE

IMPORTANCE OF DISTRIBUTION SYSTEMS:

Distribution system is one part of the Electric Power system.It is very near to the customers

compared to the generation and transmission systems.Therefore distribution system planning

starts at the consumer level.System planning is essential to assure the growing demand for

electricity which is both technically adeuate and reasonably economic.The ob!ective of the

distribution system planning is to assure the growing demand for electricity,in terms of

increasing growth rates and high load densities in an optimum way and reasonably economical.

OBECTIVES OF ELECTRICAL DISTRIBUTION SYSTEMS:

The ob!ective is to guide the students about the distribution system which is the part of anElectrical Power System and is the most important from the customer point of view. The proper

planning of distribution system ensures reliable and economic power.

PRESCRIBED TE!T BOOKS AND REFERENCE BOOKS

1.TE!T BOOKS:

T1" #Electric Power Distribution System, Engineering$"by Turan %onen,&c

%raw"hill 'oo( )ompany.

T2" Electric Power Distribution " by A.S.Pabla, Tata &c %raw"hill Publishing

company,*thedition ,+-.

2.REFERENCES:


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R1" .Electrical Power Distribution and Automation by S. Sivanagar!u, .San(ar,

Dhanpat /ai 0)o,1223.

R2". Electrical Power Distribution Systems by .4amara!u,/ight Publishers.

3. "UIDANCE ON URLS RELATED TO THE SUBECTS:

en.wikipedia.org/wiki/Electric_power_distribution

www.cfroundtable.org/meetings/060206/eaton.pdf

#.SESSION PLANS $ REVISION SCHEDULE:

In the beginning of the every ne5t class the previous topic will be reviewed for a while,

besides, after completing one unit again entire unit will be reviewed in a class for one period.

%. A& ASSI"NMENT:

Assignments will be given on the topic so far completed in the unit.

B& TUTORIALS:Tutorials will be arranged according to the Instructions received from the

6ead of the Department.

'.DISTRIBUTION OF SESSONAL MARKS:

The performance of the student will be evaluated for +22

mar(s in the sub!ect #Electrical Distribution Systems7. As per the 89T: curriculum, the

distribution shall be 12 mar(s for Internal evaluation and ;2 mar(s for the end semester

descriptive type e5amination.

In internal evaluation ,there will be two ob!ective tests for the duration of 12

minutes each and descriptive type tests for duration of 2 minutes.


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(. ATTENDANCE:

Attendance will be called for the students in the beginning of the every class.

LESSON PLAN

UNIT

NO.TOPICS TO BE COVERED

NO. OF

PERIODS

RE)UIRED REFERENCE

BOOKS


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I

+.+ Introduction to Distribution systems

+.1 =oad modelling and characteristics

+.> ?actors

+.* /elationship between the load factor and loss factor.

+.@ )lassification of loads

1

1

>

+

1

T+,/1

II

1.+ Design )onsiderations of Distribution ?eeder

1.1/adial and loop types of primary feeders

1.> oltage levels,feeder loading

1.*Design practice of the secondary distribution

system,problems

>

1

1

>

T1

III

>.+=ocation of Substations

>.1 /ating of distribution substation

>.> Service area within primary feeders

>.* 'enefits derived through optimal location of substations

1

1

1

*

T+

IV

*.+ oltage drop and power loss calculations

*.1 Derivation for voltage drop and power loss in lines,

*.> &anual methods of solution for radial networ(s,

*.* Three phase balanced primary lines

1

>

>

1

T+

@.+ Procedure for fault calculations

+

*

+

+


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V

@.* Protective Devices

@.@ Principle of operation of ?uses,)ircuit /eclosures,

line sectionaliBes and circuit brea(ers.

>

T+,/+

VI

3.+ )oordination of Protective Devices

3.1 %eneral coordination procedure

*

* T+

VII

-.+ )apacitive compensation for power"factor control

-.1 Different types of power capacitors, shunt and series

capacitors,

-.> Effect of shunt capacitor

-.* Series )ompensation

-.@ Power factor correction

-.3 Economic !ustification

-.- Procedure to determine the best capacitor location.

+

>

+

+

1

1

>

Cadhwa

VIII

oltage )ontrol

Euipment for voltage control

Effect of series capacitors

Effect of A'A/

=ine drop compensation.

+

>

1

1

+

T+


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Total classes ;2

=esson Plan may change as per the convenience.

ASSI"NMENT )UESTIONS

UNIT-I:

+FaG E5plain how the load growth in a distribution system can be obtained.

FbG A distribution substation e5periences an annual pea( load of >,@22 (C. The

total annual energy supplied to the primary feeder circuits is +2- (Ch. ?ind

i. the annual average powerii. the annual load factor

1 FaGDiscuss why loads are classified in distribution systems and how they are classifiedH

FbGE5plain the different load characteristics and their modeling.

>FaGE5amine the present trend for the future distribution system planning. FbG E5plain the various factors affecting the distribution system planning.

UNIT-II

+FaG 6ow do you apply the concept of A')D constants to radial feeders. ;J

FbG Derive an euation for receiving end voltage

.1 FaG Discuss the basic differences between radial and loop types of primary distri"

bution feeders.FbG E5plain their basic design considerations.FcG The annual input to a sub " transmission system is ;-322&wh. 22&wh. ?ind the load factor for the year and for the pea( load day.

>.Discuss in detail the factors which influence the selection of primary feeder

/ating


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UNIT-III:

+ FaG A > " K, *.+3( wye grounded feeder main has * copper conductors with

an euivalent spacing of +.2 m between phase conductors and a lagging load

power factor of 2.. Determine the L($ constant of the main feeder. =et r M+.@2>m and 5M2.-*@3 m. Also calculate the percent voltage drop in the

main if a lumped sum load of @22 (A with a lagging p.f. of 2. is connected

at the end of +m long feeder main.

FbG =ist out the benefits obtained from optimal location of substations.

1 aG )ompare four and si5 feeder patterns.

FbG &ention the various factors that are to be considered in selecting the location of substation.

>. 6ow do you analyse a substation service area with Ln$ primary feeders.

UNIT- IV:

+.Show that power loss due to load currents of the two phase, > wire lateral withfull capacity neutral is e5actly eual to 1.1@ times larger than the one in which

euivalent three phase lateral is used.

Also prove that D pu,1K M 1.+ N Dpu,>K for the above system.

.

1.Derive the e5pression for voltage drop and power loss for > phase balanced systemand non"three phase system. )ompare both of them.

*. %ive a detailed analysis of suare shaped and he5agonal shaped distribution sub"

station areas.

UNIT-V:

+.Chat are the different types of over current protective devices and e5plain theirmerits and demerits.

1.FaG Chat are the types of common faults that occur in a distribution systemHE5plain them with proper line diagram.

FbG )onsidering a typical e5ample, describe the procedure for fault current calcu"

lations in a distribution system, mentioning the assumptions to be made forthe analysis.

>.Discuss the procedure for fault current calculation in following faults

FaG >"phase fault.


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FbG Single =ine"%round fault.

FcG Double =ine"%round fault.

FdG =ine " =ine fault.

UNIT-VI:

+FaG E5plain the principle of operation of line sectionaliBer

FbG E5plain the coordination procedure between fuse and circuit brea(er.

1FaG E5plain the salient points in general co"ordination procedure.FbG E5plain ?use"/ecloser coordination.

UNIT-VII:

+FaG Cith the help of a phasor diagram, show how a series capacitor boosts thevoltageH Chat are the drawbac(s of this methodH

FbG A synchronous motor having a power consumption of @24C is connected in

parallel with a load of 1224C a lagging p.f of 2.;. If the combined load has

a power actor of 2., what is the value of leading reactive 4A supply by themotor and at what p.f is it wor(ing

1FaG E5plain the effect of shunt compensation on distribution system.FbG A >"phase substation transformer has a name plate rating of -1@24A and a

thermal capability of +12O of the name plate rating. If the connected load is

;;+34A with a 2.;@pf lagging p.f., determine the followingi. The 4A/ rating of the shunt capacitor ban( reuired to decrease the

4A load of the transformer to its capability level.

>FaG 'riefly e5plain the economic !ustification for capacitors installation .

FbG Cith the help of a phasor diagram, show how a series capacitor boosts the

voltageH Chat are the drawbac(s of this methodHii. The power factor of the corrected level.

UNIT- VIII:

+.A >"phase transformer rated -2224A and has a over load capability of +1@O ofthe rating. If the connected load is ++@24A with a 2.; pf FlagG, determine the

following

FaG The 4A/ rating of shunt capacitor ban( reuired to decrease the 4A loadof the transformer to its capability level,

FbG the p.f. of the corrected level

1FaG Crite short notes on any two methods of voltage control


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FbG #oltage control and p.f. correction why these are necessary in power systems

Chat are the disadvantages of low voltage and low p.f. of the system

>.FaG Describe the operation of A/A' with neat diagram.

FbG E5plain the basic functions of booster transformer and how it increases the

line voltage.

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