07/11/14 P.K.PATTANAIK 1

PRESENTATION ON 1.ELEMENTS OF SUB-STATION EQUIPMENTS

2.BASIC POWER SYSTEM CONCEPTS

byP.K.PATTANAIK

1. Kindly switch OFF/ Keep your Mobile phone in Vibration

mode .

2. Please interact with no CROSS TALK.

3. Kindly allow one to (speak/ ask queries) at a time.

4. Please maintain silence during presentation.

House Keeping ……

Thanks in ADVANCE for maintaining/ to maintain the HOUSE KEEPING RULES

1. Introduction

2. Acquaintance to Sub- Station Equipments

i. Working Principle

ii. Significance to Protection Scheme

iii.Name plate Study

iv.Updated technology in present Practice

3. Sub-Station Lay out/ Electrical Concepts

4. OPEN SESSION

5. Conclusion

Out Line ……

Thousands mile of journey starts from FIRST STEP

Skeleton Chart

Human being Protection system

DC +

DC -

SECONDARY

PROTECTION

ELECTRICAL PROTECTION SYSTEM

SUB STATION MAIN EQUIPMENTS

Equipments Functions

Lightning Arrester Discharges the lightning and switching surge Voltage to Earth

Wave trap Traps the high frequency signals to the system equipments

Isolator Air dis-connection of circuit for safety maintenance

Earth Switch Discharges voltage on Dead line

Circuit Breaker Auto disconnection of circuit for fault or abnormal condition

Current Transformer

Transforms current from High to Low for control and protection circuit

PotentialTransformer

Transforms voltage from High to Low for control and protection circuit

Lightning Arrester

Surge Arrestor / Lightning Arrestor

Modern surge arrestors :-

1. Metal Oxide Varistor (MOV)- ZnO2 Blocks with grain of 10μm dia.

2. Confirms IEC 60099-4 / IS 3070 with safety Vent and LCM ( Leakage Current Monitor)

3. Metal Oxide Varistor (MOV) is highly nonlinear in nature, which has sharply kinked voltage-current characteristics.

NAME PLATE STUDY ( LA)

Particulars Rating / Value

Make/Model

Sl No / Year

System Voltage 220 Kv

NDC 10 KAp

System BIL 1050KVp

MCOV 168 KV

LD Class 3

Approx. weight 135 KG

Frequency ( Hz) 50

Rated Voltage 198 KV

1. MCOV :- Maximum Continuous

Operating Voltage

2. BIL :- Basic Insulation Level

3. NDC:- Nominal Discharge Current

4. LD Class :- Line Discharge Class

5. Rated Voltage:- (system voltage x

√ 2)

√ 3

WAVE TRAP Particulars Value

Continuous Current Rating at 50 0 C ambient

1250 Amp

Max. Symmetrical Short Circuit Current For 1 Sec

31.5 KA

Rated Inductance 0.5 H

Blocking Range 150-500 KHz

Mounting Suspension

Basic Insulation Level 32.37 KVp

Standard Nominal Discharge Current for 8/20 micro Sec. Wave impulse

10 KA

Rated Voltage of Arrestor 6 KV

Tuning Broad Band

Visual Corona Extinction Voltage

156 KV

No of Turns in Main coil 28 (2 in Parallel

WAVE TRAP Working Function

ISOLATORS

Particulars Rating / Value

Particulars Rating / Value

Make Type

Voltage (KV) 245 Current ( Amp) 2000

STC (KA-Sec-KAp)

40-3-100 Impulse ( KVp) 1050

PF Voltage ( KV )

460 Frequency ( Hz) 50

DC Voltage (V) 220 AC Voltage ( V) 415

Operating Device MOM Year

Name Plate Study

Isolators/ Dis-connector

Modern Isolators :- 1. Single Break motorized type – Proper Gripping due to dragging each

other.2. One contact – provides 100% confirmed status. 3. Interlock scheme from Numerical Micro-processor Relay. 4. Operates on OFF load or EQUI-POTENTIAL Concept.

LOCKING OF ISOLATOR IN END POSITION

Switch Gear/ Circuit Breaker

UP TO 36 KV ( VCB ) 1. Quick Restoring of Dielectric

strength of Gap

2. Short gap needs lesser Control Mechanism

3. Low Weight

72 KV to 800 KV ( SF6 Filled Spring Mechanism)

4. SF6 (electronegative in nature with high quenching property and high dielectric strength

5. Spring- Spring mechanism takes less space and simple mechanism .

*CIGRE 1994:-Tech Report 83:-CIGRE analyzing worldwide Circuit Breaker advises the use of spring operating mechanism in order to ensure the highest reliability.

VCB

Circuit Breaker

420 kV SF6 GCBWith SP/Pneumatic Mechanism

Switch Gear/ Circuit Breaker

800 KV SF6 LIVE TANK

400 KV SF6 Gas Breaker

Switch Gear/ Circuit Breaker

CB with Composite Insulator CB with PIR and Graded Capacitor

Circuit Breaker Name Plate StudyParticulars Rating / Value Particulars Rating / Value

Make Rated Lightening impulse with Stand voltage

650 KVp

Type Rated short Circuit Breaking Current 31.5 KA

Rated Voltage 145 KV Rated Operating pressure 15.5 KG/cm2 - g

Rated Frequency 50 HZ First pole to Clear factor 1.5

Rated Normal Current

3150 A Rated Duration of short Circuit current 31.5 KA , 3 Sec

Rated Closing Voltage

220 V DC Rated Line Charging Breaking Current Rated SF6 Gas pressure

50 A

Rated Opening Voltage

220V DC Rated Voltage and frequency for Aux. Circuit

415 VAC , 50 HZ

GAS PRESSURE SF6

6.0 bar at 20 0

cRated operating Sequence 0-0.3S-CO-3Min-CO

Total weight with Gas

2000 KG Gas weight 9 KG

Sl. No. STD. IEC 56

Month / Year of Manufacturing

Circuit Breaker Name Plate StudyRated Lightning withstand voltage:- Peak value of standard voltage surge 1.2/50 μs that the insulation of a device can withstand. The meaning of this is “ in 1.2 micro second the voltage reaches its peak value and in 50 micro second it decays to the half of this value

1st pole to clear factor:- For 3 phase circuit breakers, arc extinction in 3 pole does not become simultaneous, for which the recovery voltage of the pole, first to extinguish the arc is of the order of 1.2 to 1.5 times the phase voltage and called First Pole to Clear Factor and defined as the ratio of the Voltage between the (healthy phase and faulty phase) to (Normal phase voltage)

Operating cycle :- The possible operational sequence of the breaker between the close and opening operation is called Operating cycle . This information is important for the choice of the breaker whether suitable for auto reclosing system or not. General operating cycle is as ( O-10s-CO-3min-CO for normal operation and O-0.3s-CO-3min-CO for auto re-close condition

Short-time Current Rating:- The circuit breaker must be capable of carrying short-circuit current for a short period while another circuit breaker (in series) is clearing the fault. The rated short-time current is the rms value (total current, both A.C and D.C components) of the current that the circuit breaker can carry safely for a specified short period

Transient Recovery Voltage (TRV) or Re-striking voltage:-For the AC circuit breaker , for the case of current interruption even after current becoming zero, certain voltage appears across the contacts, which is transient in nature and called TRV or Re-striking Voltage.

Instrument Transformer ( CT, PT)

Current Transformer Principle

I2

I1

Current sensor

Voltage Transformer Principle

Magnetic circuit (core)

U1 U2

Voltage sensor

Secondary Windings

Primary Windings

CVT Principle

OUT DOOR S/S CTs (Live Tank CT)

Live Tank CT Dead Tank CT U Shape

Voltage Transformer CVT

Capacitor elements

Capacitor column

Insulating oil

Insulator flange

Secondary terminal box

Inductance

MV Transformer

Oil expansion device

Damping circuit

Combined CT and PT unit

Optic Fiber CT

Current Transformer Principle

CT NAME PLATE STUDY Particulars Rating / Value Particulars Rating / Value

Make Type

Ref. Standard IS 2705-1992 HSV/NSV 245/ 220 KV

BIL 1050/460 KV S.T.Current 40/ 1 KA/Sec

Frequency 50 HZ Wt. Of Oil 350 KG

Making Capacity 100 KAp TOTAL WEIGHT 1200 KG

Sl. No/YEAR

P1

C1P2

C2

S1 S2 S3

RATIO 400-200-100/1-1-1-1-1

PRI/SEC CURRENT (A) 400/1 200/1 100/1

PRI. CONN. P1C1– P2C2 C1-C2 C1-C2

SEC. CONN.

CORE 1 1S1-1S3 1S1-1S3 1S1-1S2

CORE2 2S1-2S3 2S1-2S3 2S1-2S2

CORE3 3S1-3S3,S’ 3S1-3S3,S’ 3S1-3S2,S’

CORE4 4S1-4S3 4S1-4S3 4S1-4S2

CORE5 5S1-5S3 5S1-5S3 5S1-5S2

CORE 1 2 3 4 5

OUT PUT* - - 40 - -

ACC. CLASS* PS PS 0.5 PS PS

ISF/ALF* - - ≤ 5 - -

Vk (V) Min* 1200 1200 - 1200 1200

I exc@Vk *(mA) Max * 25 25 - 25 25

Rct at 75 0 C Max* 5 5 - 5 5

* AT 400/1 AND 200/1 RATIO ONLY

CT NAME PLATE STUDY

CVT NAME PLATE STYUDY Particulars Rating / Value Particulars Rating / Value

Make Sl. No.

Type Rated Voltage 220/√3 KV

Highest System Voltage 245 KV Rated Insulation Level 245/460/1050 KV

Total Creepage 6125 min. nom.mm Rated Frequency 50 HZ

Wt of Oil 140 KG Standard IEC : 60186/ IS : 3156

Total Weight 750 KG HV ( Pri) Capacitance 4840 pF

Int. V ( Sec ) Capacitance 48400 pF Equip. Cap ( Cn ) for PLCC

4400 + 10 % - 5 % pF

Nom. Intermediate Volt. 20/√3 KV Temp. category - 5 to 55 0 C

Total Thermal Burden 750 VA Class of Insulation A

1 ph solidly earth Connection Suitable for hot Line Washing

Month / Year of Manufacturing

Voltage Divider ratio 220/√3 KV/20/√3 KV

Voltage Factor 1.2 Continuous / 1.5 for 30 Sec

G.A Drg. No.

Rated Sec. Voltage Terminal Marking Rated burden VA Acc. Class

110/√3 V , 110/√3 V (1a-1n), (2a-2n) 150, 150 0.5, 0.5

110/√3 V 3a-3n 50 3P

CVT NAME PLATE STUDY

Polarity and connection.Star connection circuit IR = I , angle( 0 ) IY = I, angle (-120) IB = I, angle (120) IR+ IY+ IB= IN

CT Circuit Connection Principle

R

R

By

Application of Instrument Transformers

DC +

DC -

SECONDARY

PROTECTION

ELECTRICAL PROTECTION SYSTEM

600/1 A

2400 A 4800A

4 A 4A

0 A

FAULT OUTSIDE Differential ZONE

1200/1A

132Kv

66Kv

600/1A

2400 A 4800A

4A 4A

8A

1200/1A

132KV 66Kv

FAULT INSIDE DIFFERENTIAL ZONE

PROTECTION PHILOSOPHY ( WHY)

1. Safety to Equipments and working personnel

2. To minimize damage and interruption

3. To prevent the Electric Failure

4. Loss of revenue due to outage

5. Inconvenience to the consumers

6. High Down time for repair / replacement

If No…. Then What…

Circuit Breaker

TripCoil

CircuitBreakerMecha-

nism

DC-System

ProtectionEquipment

CT

VT

TE

Protection System

Fault Clearance System

The Fault Clearance System

1. What is Relay?A device which detect intolerable or unwanted

conditions within the assigned area.A watchman or watchdog for the

equipment/areaSilent sentinels to power system.

2. How relays are differentiated?Functional categoriesInput quantitiesOperating PrinciplesPerformance Characteristics.

3. What are functional types?Protective relay.Monitoring relay.Reclosing relay.Regulating relay.Synchronising relay.

4. What are various input type?Voltage, Current, Temperature, Flow, Vibration, Pressure.

PROTECTION DEVICES

PROTECTION DEVICE FOR GRID SUB STATION

Self-supervision

Setting groups

Programmable logic

Adaptive schemes

Multiple protection characteristics

Communication capability

Instrumentation features

FEATURES OF NUMERICAL RELAYS

ADDITIONAL FEATURES

State-of-the-art-technology Simple design Operational flexibility Low relay burden Reduction of panel size & wiring Reduced commissioning time Reduced testing time Fault disturbance recording & analysis Sequence of events recording

PROTECTION SYSTEM

132KV BUS

132 KV D/C TR. LINE

Generation Evacuation

220 KV BUS

11KV BUS

132/11KV T/F

LINKAGE TO GRID

220 KV LINEGenerator protection

Line protection

T/F Protection

Bus Bar Protn.

LBB

STATOR E /F

GEN. DIFF.

OVER ALL DIFF.

INTER TURN

Reverse Power

Field Failure

T/F INTERNAL PROT.: Buchholz ,Wdg. Temp. , Oil temp. & PRV trip/alarm

GENERATOR PROTECTION

TRASFORMER PROTECTION

Differential element

100MVA , 220/66 KV

Yy0

262.5A

00

875A

00

400/1 1200/1

REF HV

REF LV

400/1 1200/1

Differential zone

HV REF ZONE

LV REF ZONE

BACK UP O/C & E/F

Over fluxing

Buchholz, WT, OT, & PRV alarm / trip

BUS FAULT

BUS BAR PROTECTIONBUS-1

BUS-2

BUS BAR PROTECTIONZONE-1

BUS BAR PROTECTIONZONE-1

ZONE-2

X X

X XX

X

XX

X

X

XX

A B C D

LINE PROTECTION

Z1Z2Z3

Z1

Z2

Z3

Event Logger

Disturbance recorder

Fault Locator

Numerical relays

IED ( Intelligent Electronics Device)