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Agenda

Extension of existing ( OLD) BUS BAR PROTECTION

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

TIME SYNCHRONISATION OF RELAYS

DISTRUBANCE RECORD WORK STATION

TEST PLUGS & TEST EQUIPMENTS

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HV Application: Busbar Protection

Kirchhoffs Principle applied to a healthy system

I = 0

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

I1 = I2 + I3I1 - I2 - I3 = 0

I1 I3I2

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Without Busbar Protection (1)

F2F1

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

There are fewer faults on busbars than on other parts of the power system

No dislocation of system due to accidental operation of busbar protection.

Slow fault clearance.Busbar faults at F1 and F2 are cleared by remote time delayed protection oncircuits feeding the faults:

Time Delayed Overcurrent orTime Delayed Distance Protection

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Busbar Faults Are Usually Permanent

CAUSES : Insulation failures Circuit breaker failures Falling debris Isolators operated outside their ratings Safety earths left connected

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

urrent trans ormer a ures

THEREFORE :Circuit breakers should be tripped and locked

out by busbar protection

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Busbar Protection must be:

RELIABLE

Failure could cause widespread damage to the substation

STABLE

False tripping can cause widespread interruption ofsupplies to customers

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

DISCRIMINATING

Should trip the minimum number of breakers to clear thefault

FAST

To limit damage and possible power system instability

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1 Breaker Scheme

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

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1 Breaker Bus Protection

87

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

87

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Double Bus Protection

Z1

Z3

Z2

Z4

BS

BC1 BC2F1 F2 F3 F4

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

BCM1

BCM2

FM1

FM2

FM3

FM4

BSM

Z1Z3

ZCK

Z2Z4

ZCK

Z1 Z2 Z4Z3 ZCK

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Effect of C.T. Location onBusbar Protection Performance

Circuitprotection

Interlockedovercurrentrelay

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

Busbarprotection

protection

Busbarprotection

Overlapping C.T.s

Circuitprotection

Busbarprotection

Interlockedovercurrentrelay

All C.T.s on line sideof circuit breaker

All C.T.s on Busbar sideof circuit breaker

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High Impedance Protection

Simple system to apply andextend.

High sensitivity for phase and

earth faults.

Extremely stable for externalfaults.

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

CT requirements: Equal ratiosClass X

May require stabilising resistors,RST.

May require non-linear resistors

(Metrosils).

RST

METROSIL

87

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Isolator Auxiliary Switches

R

M

A B C D

Auxiliary switches should :1) Close before the isolator

closes

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

a b c d

rm

Buswires

2) Open after the isolatoropens

In order to maintain stabilityon switching.

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Differential Relay CircuitABCN

Zone bus wires

95X

95X

95X

Bus wire short contacts

Supervisionrelay

95

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

Stabilising

resistors

87 87 87

v v v

Metrosil

resistors

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Typical Trip Relay Arrangement

Double Busbar System

In Out

CSS - M1

CSS - M2

87M1 - 1

87M2 - 1

-

M1 RM2

a1

c196E

96D2

96D1

-+87CH - 1

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

CSS - R

b1

c2

D.C. Buswires

80T

96H2

96H1

96G

96F2

96F1

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Single Bus Protection

F1 F2 F3 F4

Z2Z1

BS

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

FM1

FM2

FM3

FM4BSM

Z1

ZCK

Z2

ZCK

ZCKZ1 Z2

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Double Bus Protection

Z1

Z3

Z2

Z4

BS

BC1 BC2F1 F2 F3 F4

ALSTOM 2010. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to anyparticular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, withoutexpress written authority, is strictly prohibited.

BCM1

BCM2

FM1

FM2

FM3

FM4

BSM

Z1Z3

ZCK

Z2Z4

ZCK

Z1 Z2 Z4Z3 ZCK