LBB & BUSBAR

LBB & BUSBAR PROTECTIONLBB & BUSBAR PROTECTIONLBB & BUSBAR PROTECTIONLBB & BUSBAR PROTECTIONPREPARED BYPREPARED BY

GOPALA KRISHNA PALEPUGOPALA KRISHNA [email protected], [email protected],

Mobile:9440336984Mobile:9440336984

NOMINICLATURENOMINICLATURE

LBB : Local Breaker Backup Relay.

BFR : Breaker Failure Relay.BFR : Breaker Failure Relay.

CBF : Circuit Breaker Failure Relay.

ANSI Code : 50Z or 50BF.

This is Current Operated Relay.

BASICS OF LBB/BFR PROTECTIONLOCALLOCAL BREAKERBREAKER BACKUPBACKUP PROTECTIONPROTECTION

A PROTECTION WHICH IS DESIGNED TO CLEAR A SYSTEMFAULTY BY INITIATING TRIPPING OTHER CIRCUIT BREAKER(S) INTHE CASE OF FAILURE TO TRIP OF THE APPROPRIATE CIRCUITBREAKER.

IN MODERN NETWORKS THE CRITICAL FAULT CLEARINGTIME MAY BE LESS THAN 200ms. HENCE, IF THE FAULT IS NOTTIME MAY BE LESS THAN 200ms. HENCE, IF THE FAULT IS NOTCLEARED DUE TO FAILURE OF THE PRIMARY PROTECTIVE RELAYSOR THEIR ASSOCIATED CIRCUIT BREAKER, A FAST ACTING BACK-UP PROTECTIVE RELAY MUST CLEAR THE FAULT.

THERE ARE TWO BASIC FORMS.

REMOTE BACK-UP.

LOCAL BACK-UP.

REMOTEREMOTE BACKBACK--UPUPPROVIDES BACK-UP PROTECTION FOR THE BOTH THEPROVIDES BACK-UP PROTECTION FOR THE BOTH THE

RELAYS (MAIN-1 & MAIN-2) AND BREAKERS AT REMOTESUBSTATION.

LOCALLOCAL BACKBACK--UPUPLOCAL BACK-UP PROTECTION CAN BE DEVIDED INTO TWOCATAGORIES.RELAY BACK-UPBREAKER BACK-UP

RELAY BACKRELAY BACK--UPUP

DUPLICATE PRIMARY PROTECTION. i.e ONE IS NON SWITCHED

DISTANCE PROTECTION AND ANOTHER IS SWITCHED DISTANCE

SCHEME OR OTHER WISE BOTH SCHEMES CHARECTERSTICS ARE

DIFFERENT (QUADRALATERAL, MHO CIRCULAR, TAMOTO & OPTICAL )

OR DIFFERENT MANUFACTURERS(ABB, ALSTOM, SIEMENS, EASUN

REYROLL, SEL, GE, NXT PHASE OR BASLER) OR DIFFERENT METHODS (i.e

ELECTROMECHANICAL, STATIC, NUMERICAL{MICROPROCESSOR &DSP}).ELECTROMECHANICAL, STATIC, NUMERICAL{MICROPROCESSOR &DSP}).

IF MAIN-1 & MAIN-2 ARE NUMERICAL RELAYS BOTH SHOULD BE

SEPARATE CHARECTERESTICS AND SEPARATE MODELS AND ALL

FEATURES SHOULD BE AVAILABLE IN BOTH SCHEMES AND BOTH

RELAYS SHOULD BE 100% REDENDENCY IN ALL ASPECTS.

TO INCREASE THE SECURITY, THE CIRCUIT BREAKER HAS TWO

TRIP COILS, ONE IS CONNECTED TO MAIN-1 PROTECTION AND ANOTHER

IS CONNECTED TO MAIN-2 PROTECTION.

BREAKER BACKBREAKER BACK--UPUP

BECAUSE OF THE HIGH COST OF HIGH VOLTAGE CIRCUIT

BREAKERS, IT IS NOT FEASIBLE TO DUPLICATE THEM.

IN CASE OF A BREAKER FAILURE THE OTHER CIRCUIT BREAKERS

CONNECTED TO THE SAME BUS AS THE FAULTED BREAKER MUST THERE

FORE BE TRIPPED.

LBB/BFR FLOW CHART

MAIN PROTECTIONOPERATED

YESTRIP MAIN

BREAKER

FAULT CLEARED

YESRESET

BREAKER FAILURE

SCHEME

YES INITIATEBFR

WAIT FOR FAULT

CLEARENCE

AND

NO

TRIPBACK-UP/Adjacent

BREAKERS

The Breaker Failure Protection (LBB/BFR) can operate single-stage/two-stage.

RETRIP

stage.When used as single-stage protection, the Bus trip command is given tothe adjacent Circuit Breakers if the protected feeder Breaker fails.When used as two-stage protection, the first stage can be used torepeat the trip command to the relevant feeder Breaker, normally on adifferent trip coil, if the initial trip command from the feeder protectionis not successful. The second stage will result in a Bus trip to theadjacent Breakers, if the command of the first stage is not successful.

LBB/BFR TIME CO-ORDINATION CHART

FAULT OCCURS

NORMAL

NORMAL CLEARING TIME

NORMAL

CLEARING

BREAKER

INTURUPTING TIME

PROTECTIVE RELAY

FOR EX: DISTANCE RELAY

BREAKER FAILURE RELAY START

MARGIN

RESETTING TIME OF THE

CURRENT MEASURING UNITS

SET TIME OF THE TIME MEASURING UNIT TRIPPING

RELAY

TIME

BACK-UP BREAKER

INTERUPTING TIME

MARGIN

~30ms ~60ms <12ms

INOPERATIVE

BREAKER

BREAKER FAILURE RELAY START

TOTAL CLEARING TIME OF THE BREAKER FAILURE RELAY

MAXIMUM FAULT CLEARING TIME BEFORE SYSTEM INSTABILITY

LBB/BFR LOGIC

PHASE L1

PHASE L2/E

PHASE L3

CURRENT INPUTS

~

|||

A/DCONVERTER

&I > ISET

I > ISET

PHASE CURRENT SET POINT

&> 1

LED

(PHASE START)

ALARM RELAY

(PHASE START)

ALARM RELAY|||EARTH CURRENT SET POINT

CIRCUIT BREAKER FAILURE INITIATE

BINARY INPUT

OUT PUT OF DISTANCE RELAY ORSHORT CIRCUIT CURRENT RELAY

TIMING/OUTPUT STAGE

TIME STAGE T1

& LED

TRIP T1 RELAY

LED

(EARTH START)

ALARM RELAY

(EARTH START)

0 1

0 1

TIME STAGE T2

TIME STAGE T2SWITCHED OFF

&

&

&

O

> 1

LEDCB FAILURE

INITIATE

LED

TRIP T2RELAY

ALARM T1

RELAY

LED

CBIP Guidelines on ProtectionLBB/ BFR PROTECTION COMMENTSLBB/ BFR PROTECTION COMMENTS

In the event of any CB fails to trip on receipt ofcommand from Protection relays, all CBs connected to

GENERALGENERAL

command from Protection relays, all CBs connected tothe Bus section to which the faulty circuit Breaker isconnected are required to be tripped with minimumpossibly delay through LBB Protection.

This Protection also Provides coverage for faultsbetween CB and CT which are not cleared by otherprotections.protections.

CBIP Guidelines on ProtectionRECOMMENDATIONS FOR LBB/BFR PROTECTIONRECOMMENDATIONS FOR LBB/BFR PROTECTION

i) In all new 400KV and 220KV Substations as well asGenerating Stations Switch Yard, it must beprovided for each Circuit Breaker.provided for each Circuit Breaker.

ii) For existing Switch Yards, it is considered a must at400KV level and also 220KV Switch Yards havingmultiple feed.

iii) In case of radially fed 220KV Substations, Provisioniii) In case of radially fed 220KV Substations, Provisionof LBB Protection is desirable but not essential.

CBIP Guidelines on ProtectionLBB/BFR REQUIREMENTSLBB/BFR REQUIREMENTS

i) Have Short Operation and Drop off times.

ii) Have 3 Phase Current elements with facility forPhase wise initiation.

iii)have current setting range such that these can be setminimum 200mA for Line and 50mA for generators(for 1A CT for secondary).

iv) Have one common associated timer with adjustablesetting.

REQUIREMENTS OF CIRCUIT BREAKERSREQUIREMENTS OF CIRCUIT BREAKERSREQUIREMENTS OF CIRCUIT BREAKERSREQUIREMENTS OF CIRCUIT BREAKERS

� Operating Time

� Breaking Capacity

� Stuck Breaker Probability

� Operating Sequence / Duty cycle

CBIP Guidelines on ProtectionLBB/BFR OPERATIONLBB/BFR OPERATION

� The Breaker Failure Protection (LBB/BFR) canoperate single-stage/two-stage.

�When used as single-stage protection, the Bus trip�When used as single-stage protection, the Bus tripcommand is given to the adjacent Circuit Breakers ifthe protected feeder Breaker fails.

�When used as two-stage protection, the first stagecan be used to repeat the trip command to therelevant feeder Breaker, normally on a different tripcoil, if the initial trip command from the feedercoil, if the initial trip command from the feederprotection is not successful. The second stage willresult in a Bus trip to the adjacent Breakers, if thecommand of the first stage is not successful. (This isMore recommended)

CBIP Guidelines on ProtectionLBB/BFR SPECIAL COMMENTSLBB/BFR SPECIAL COMMENTS

(i) The relay is separate for each breaker and is to beconnected in the secondary circuit of the CTsassociated with that particular breaker.

(ii)For line breakers, direct tripping of remote endbreaker(s) should be arranged on operation of LBBprotection.

For transformer breakers, direct tripping ofbreaker(s) on the other side of the transformershould be arranged on operation of LBB protectionshould be arranged on operation of LBB protection

(iii) For lines employing single phase auto reclosing,the LBB relays should be started on a single phasebasis from the trip relays.


(iv) The CT sec core may be separate core, if available.

Other wise it shall be Clubbed (in series) with Main-1

or Main-2 protection.

(v)It is considered a good practice to have DC circuits ofGr.A and Gr. B protections and relay independent.

(vi) LBB cannot operate without proper initiation. It isgood practice to provide redundant trip output andbreaker fail input where other forms of redundancydoes not exist.does not exist.

(vii) Separation should be maintained betweenprotective relay and CB trip coil DC circuit so thatshort circuit or blown fuse in the CB circuit will notprevent the protective relay from energizing the LBBscheme.


(viii) In addition to other fault sensing relays the LBBrelay should be initiated by Bus bar protection, sincefailure of CB to clear a bus fault would result in theloss of entire station if BFP relay is not initiatedloss of entire station if BFP relay is not initiated

(ix) Tripping logic of the bus bar protection schemeshall be used for LBB protection also.

(x) For breaker-fail relaying for low energy faults likebuchholz operation, special considerations may haveto be given to ensure proper scheme operation byto be given to ensure proper scheme operation byusing C.B. contact logic in addition to currentdetectors.

CBIP Guidelines on ProtectionLBB/BFR SETTING CRITERIALBB/BFR SETTING CRITERIA

(i) Current level detectors should be set as sensitive asthe main protections

A general setting of 0.2 A is commonly practiced forLines and Transformers

(ii) Timer setting should be set considering breakerinterrupting time, current detector reset time and amargin. Generally a timer setting of 200 ms has beenfound to be adequate.found to be adequate.

LBB/BFR connections during STATIC RelaysLBB/BFR connections during STATIC Relays

CT CORE-5: Main-1 Distance Relay & Fault Locator are inseries.

CT CORE-4: Main-2 / Backup Relay, LBB/BFR & DisturbanceRecorder are in series.

CORE-5

IN CASE OF LINE

1-5

2C

B

FAULTFAULTLOCALOCA--TORTOR

21 L1 /21 L1 /87 L187 L1

forforLineLine

P2

P1

CORE-4

IN CASE OF LINE

LineLine

LBBLBBBFRBFR

21 L2 /21 L2 /87 L287 L2ForForLineLine

DISTDISTRECREC

P1

P2

P1

LBB/BFR connections during NUMERICAL RelaysLBB/BFR connections during NUMERICAL Relays

1. Fault Locator is inbuilt feature in both Distance Schemes.2. Disturbance Recorder is also inbuilt feature in both Distance

Schemes.3. Most of the Utilities are not accepting the LBB is Inbuilt feature of

Main-1 or Main-2/ BU Protection. But Accepting Inbuilt feature ofBUSBAR Protection.BUSBAR Protection.

CORE-5

P2

1-5

2C

B

21 L1 /21 L1 /

87 L187 L1CORE-5

CORE-4

P1

P2

P1

forfor

LineLine

LBBLBBBFRBFR

21 L2 /21 L2 /

87 L287 L2

ForFor

LineLine

NEXT DEVELOPMENTNEXT DEVELOPMENT 1. LBB is now Part of BUSBARProtection Relay, ForDistributed Architecture orCentralised Architecture.

2. In case of DistributedArchitecture, CT connections,Binary Input & Output

CORE-5

21 L1 OR

87 L1

1-5

2C

B

P2

P1 Binary Input & OutputConnections are up to BAY /Peripheral Unit and BU/PU toBUSBAR is Fiber Optic Link

3. In case of CentralisedArchitecture I, V, BI & BO toCentral Unit.

CORE-4

CORE-2

C

E

ABB Network Partner AG REL531

21 L2 OR

87 L2

50 Z + 87BBLBB IS INBUILTCENTRALISED

P1

P2

P1

P2

CORE-1 FIBEROPTIC

OR

C

E

50Z +87BBCENTRAL UNITLBB IS INBUILT

BUSBAR

ABB Network Partner AG

CENTRALISED

BUSBAR

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

ABB Network Partner AG REL 316*4

C

E

BU/PU

P1

P2

P1

NEXT DEVELOPMENTNEXT DEVELOPMENT

1. ABB is developed the New Concept i.e2. CT connections are up to Main-1 Protection & Main-1 to Bay Unit and

BAY UNIT to BUSBAR is Fiber Optic Link. (Numerical DistributedArchitecture) and

3. Similarly for Main-2 Protection.4. The CB and Isolator Status Given to Bay Unit.4. The CB and Isolator Status Given to Bay Unit.

CORE-5

21 L1 / 87L1

FO FO

BAY UNIT CENTRAL UNIT

1-5

2C

B

P2

P1

CORE-4

21 L2 / 87L2

FO FO

BAY UNIT CENTRAL UNIT

P2

P1

CORE-1

NEXT DEVELOPMENT FOR REDUNDANT BUSBAR PROTECTION FOR DISTRIBUTED OR CENTRALISED ARCHITECTURENEXT DEVELOPMENT FOR REDUNDANT BUSBAR PROTECTION FOR DISTRIBUTED OR CENTRALISED ARCHITECTURE

1-5

2C

B

P2

CORE-1

CORE-2

OROR

P1

P2

P1

P2

CORE-2 FIBEROPTIC

CORE-1

C

E

50Z +87BBCENTRAL UNITLBB IS INBUILT

BUSBAR


BU/PU

FIBEROPTIC

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16


C

E

P2

P1

P2

P1

RECENT DEVELOPMENTRECENT DEVELOPMENT

1. New Relay Introduced i.e Breaker Management Relay.2. In this LBB (50Z) + A/R (79) + Check Syn (25)+ O/C&E/F

(67/51/50) are Inbuilt features.3. This is connected to Centralised Unit Through Fiber Optic or CT

Connections are in Series to BUSBAR.

CORE-2P2

P1

BMR

FO

1-5

2C

B

CORE-1P2

P1

BMR

FO

INITIATION TO LBB / BFRINITIATION TO LBB / BFR

1. 21L1 & 21L2 Operation will operate 1-Ph Trip Relays (186-R,Y,B & 286-R,Y,B). These Relays will

energise the trip coils of the Circuit Breaker and initiate the LBB Relay.

2. 87T1 & 87T2 & Other Relays will operate Master Trip Relays / High Speed Trip Relays (86Gr-A,

86Gr-B). These Relays will energise the trip coils of the Circuit Breaker and initiate the LBB Relay.

3. BUSBAR Relays will operate Master Trip Relays / High Speed Trip Relays (96-BB). These Relays will

energise the trip coils of the Circuit Breaker and initiate the LBB Relay.

4. Incase of Transfer Bus System or Bypass Isolator System initiation of LBB is selection of Normal /4. Incase of Transfer Bus System or Bypass Isolator System initiation of LBB is selection of Normal /

Transfer switch Position.

LBB / BFR Tripping LogicLBB / BFR Tripping Logic

When LBB Operated following Output Operations will Taken Place.� To Main-1 Disturbance Recorder.

� To Main-2 Disturbance Recorder..

� To 86 Gr-A Bi-Stable relay.

� To 86 Gr-B Bi-Stable relay.� To 86 Gr-B Bi-Stable relay.

� To 87BUSBAR Output Relays ( 96BB1 and/or 96BB2).

� Direct Trip Ch-1 to Other end.

� Direct Trip Ch-2 to Other end.

� To Annunciation.

� To SER / RTU.

� Incase of ONE & HALF CB System, Central/ Tie LBB Having Duplicate Tripping Logics for

2 sides of Main Bays.

MAIN-1 (21L1) PROTECTION OPERATED

21 MAIN-1

TO LBBTO TC-1

+VE -VE

R PHASE

186 R1

186 R2

TO LBBTO TC-1

TO TC-2

TO LBBTO TC-1

TO TC-2

TO TC-1

TO TC-2

TO TC-1

TO TC-2

Y PHASE

186 Y1

186 Y2

BINARY OUTPUT

TO TC-2

TO LBBTO TC-1

TO TC-2TO TC-1

TO TC-2

B PHASE

186 B1

186 B2

MAIN-2 (21L2) PROTECTION OPERATED

21 MAIN-2

TO LBBTO TC-1

+VE -VE

R PHASE

286 R1

286 R2

TO LBBTO TC-1

TO TC-2

TO LBBTO TC-1

TO TC-2

TO TC-1

TO TC-2

TO TC-1

TO TC-2

Y PHASE

286 Y1

286 Y2

BINARY OUTPUT

TO TC-2

TO LBBTO TC-1

TO TC-2TO TC-1

TO TC-2

B PHASE

286 B1

286 B2

86 GA (MASTER TRIP RELAY) OPERATION

21L1:MAIN-1

+VE

-VERESET

OPERATED

PB

TO ANN

OPERATED

TO CL I/L

TO LBB

TO TC-1

TO SER

OTHER PROTECTIONS

87T1:MAIN-1

TO TC-2

TO M1 DR

TO M2 DR

86 GA MASTER TRIP RELAY

86 GB (MASTER TRIP RELAY) OPERATION

21L2:MAIN-2

+VE

-VERESET

OPERATED

PB

TO ANN

OPERATED

TO CL I/L

TO LBB

TO TC-1

TO SER

OTHER PROTECTIONS

87T2:MAIN-2

TO TC-2

TO M1 DR

TO M2 DR

86 GB MASTER TRIP RELAY

96 BB (MASTER TRIP RELAY) OPERATION

87 BUSBAR

TO D/T-1

+VE

-VERESET

OPERATED

PB

FO

R S

ING

LE

BU

S S

YS

TE

M,

ON

E &

HA

LF

CB

SY

ST

EM

,D

OU

BL

E C

B &

DO

UB

LE

BU

S S

YS

TE

M

& R

ING

MA

IN B

US

SY

TE

M

TO D/T-1

TO CL I/L

TO LBB

TO TC-1

TO D/T-2

TO ANNUN

TO SER

FROM LBB

FO

R S

ING

LE

BU

S S

YS

TE

M,

ON

E &

HA

LF

CB

SY

ST

EM

,D

OU

BL

E C

B &

DO

UB

LE

BU

S S

YS

TE

M

& R

ING

MA

IN B

US

SY

TE

M

TO TC-2

TO M1 DR

TO M2 DR

96 BB MASTER TRIP RELAY

FO

R S

ING

LE

BU

S S

YS

TE

M,

ON

E &

HA

LF

CB

SY

ST

EM

,D

OU

BL

E C

B &

DO

UB

LE

BU

S S

YS

TE

M

& R

ING

MA

IN B

US

SY

TE

M

LBB Operation & Output(SINGLE BUS / DOUBLE BUS / QUAD BUS SYSTEM)

INITIATION

186 R186 Y

186 B 50X

LBB / BFR

TIMER

186 B

286 R286 Y

286 B

86 GR-A

86 GR-B

96 BB

+VE

TO D/T CH-1

TO D/T CH-2

TO ANNUN

TO MAIN1 DR

TO MAIN2 DR

TO SERTO 86 GR-A

-VE50X

TO 86 GR-A

TO 86 GR-B

TO BUSBAR

TO 96 BB

LBB Operation & Output(TRANSFER BUS / BYPASS ISO SYSTEM)

INITIATIONINITIATION

186 R186 Y

186 B 50X

LBB / BFR

TIMER

186 B

286 R

286 Y

286 B

86 GR-A

86 GR-B

96 BB

+VE

TO D/T CH-1

TO D/T CH-2

TO ANNUN

TO MAIN1 DR

TO MAIN2 DR

TO SERTO 86 GR-A

-VE50X

+VE

N TN T..

TO 86 GR-A

TO 86 GR-B

TO BUSBAR

+VE . In case of Feeder bay / Transformer Bay

+VE

N TN T.In case of Transfer Bay for Transfer Bus System initiation to that LBB

In case of Bus Coupler Bay for Bypass ISO System initiation to that LBB+VE

N TN T.

LBB Operation & Output(ONE&HALF CB SYSTEM)

INITIATIONINITIATION

186 R186 Y

186 B +VE -VE50X1

LBB / BFR

TIMER

186 B

286 R286 Y

286 B

86 GR-A

86 GR-B

96 BB

+VE

TO D/T CH-1

TO D/T CH-2

TO ANNUN

TO MAIN1 DR

TO MAIN2 DR

TO SERTO 86 GR-A

-VE

TO D/T CH-1

TO D/T CH-2

-VE50X2

TO 86 GR-B

TO BUSBAR

TO D/T CH-2

TO ANNUN

TO MAIN1 DR

TO MAIN2 DR

TO SERTO 86 GR-A

TO 86 GR-B

TO BUSBAR

IN THIS 2 NOS TRIPPING AUXILIARY RELAYSPROVIDED FOR MAIN CB & TIE CB.IN CASE OF TIE LBB, ONE FOR BUS-1 MAIN

CB & OTHER FOR BUS-2 MAIN CB.

LBB/BFR PROTECTION

2-52CB 3-52CBBUS-1 BUS-2

LINE1 AT/F-1

1-52CB

50Z 50Z

� LBB/BFR IS LOCAL BREAKER BACKUP PROTECTION/ BREAKER FAILURE RELAY.� 1No LBB RELAY IS PROVIDED FOR EACH BREAKER.� LBB IS CURRENT OPERATED RELAY.� LBB RELAY IS ENERGISED WHEN MASTER TRIP RELAY(86-A OR/AND 86-B OR/AND 96)

OPERATES OR SINGLE PHASE TRIP RELAYS OPERATES AND GIVEN SIGNAL TO BREAKER FOR TRIP.

50ZT

BREAKER FOR TRIP. � LBB RELAY TIME DELAY IS PROVIDED.� LBB RELAY OPERATES WHEN THE BREAKER IS UNDER TROUBLE/ FAILS TO OPERATE. � AFTER ENERGISED THE LBB RELAY AND TIME DELAY COMPLETES, EVEN CURRENT IS

THERE THIS THINKS BREAKER FAIL TO OPERATE AND GIVEN SIGNAL AS PER SCHEME DESCRIBED NEXT PRESENTATION.

� NEW CONCEPT: Normally the CT connections for LBB/BFR relay is in series with Main-2 Protection.In case of Numerical Distributed LBB/BFR and Centralized Bus-Bar System, the CT connections forBus-Bar are terminated at LBB/BFR and Centralized Bus-Bar is interconnected by Fiber-Optic cable.

1-52 CB LBB/BFR OPERATION

86

86

--AA

BB

ABBABBREL521REL521MAINMAIN--11

ABBABB

86

86

--AA

BB

86

86

--BB


86

86

--BB

BUSBAR-1

PROTECTION (96-BB )

OPTD

AND BUSBAR-1

ISOLATED

DIRECT TRIP 1&2

VIA CARRIER TO

OTHER END

50Z

TO 96-ZT TRIP RELAY

OF TIE CB(2-52CB)

BUS-1 BUS-2

1-52CB 3-52CB2-52CB

TC-1 TC-2

ISOLATED

TC-1TC-2

Breaker Failure Relay of the Main Circuit Breaker Trips the 1. Connected Bus Bar Protection, 2. Tie Circuit Breaker 96/50Z Relay &

3. Remote End Circuit Breaker through Carrier Tripping.



86

86

--AA

ABBABBRET521RET521MAINMAIN--11

ABBABBREL316REL316MAINMAIN--22 8

68

6--BB


TO 96-BB TRIP RELAY

OF LINE CB(1-52CB)

DIRECT TRIP 1&2

VIA CARRIER

TO OTHER END

TO 96-BB TRIP RELAY

OF AT/F(ICT) CB (3-52CB)

INTER TRIP TO

LVCB & TBCCB

50ZT

BUS-1 BUS-2

1-52CB 3-52CB2-52CB

TC-1 TC-2

OF LINE CB(1-52CB) OF AT/F(ICT) CB (3-52CB)

Breaker Failure Relay of the Tie Circuit Breaker Trips the 1. Both Sides Main Circuit Breakers and 2. Remote End Circuit Breakers through carrier Tripping

( In case of Transformer, LV Circuit Breaker)


86

86

--AA

BB


ABBABB

86

86

--AA

BB

86

86

--BB


86

86

--BB

BUSBAR-2 (96 BB)

PROTECTION OPTD

AND BUSBAR-2

ISOLATED

INTER TRIP TO

LV CB & TBC CB

50Z

TO 96-ZT TRIP RELAY

OF TIE CB(2-52CB)

BUS-1 BUS-2

1-52CB 3-52CB2-52CB

TC-1 TC-2 TC-1TC-2

ISOLATED

Breaker Failure Relay of the Main Circuit Breaker Trips the 1. Connected Bus Bar Protection 2. Tie Circuit Breaker 96/50Z Relay &

3. Remote End Circuit Breaker ( In case of ICT, LV CB)

DISTRIBUTED LBB & NUMERICAL CENTRALISED BUS BAR PROTECTION

BUS-1

1-5

2

4-5

2

7-5

2

10

-52

13

-52

OR OR

(REB 500) ABB (7 SS 52) SIEMENS (MICOM P740) AREVA

12

-52

45

-52

78

-52

10

11

-52

13

14

-52

BUS-2

3-5

2

6-5

2

9-5

2

12

-52

15

-52

OR OR

LBB/BFR PROTECTION

1-52CB 2-52CBBUS-1 BUS-2

LINE1

50Z 50Z

� THE ABOVE SYSTEM IS DOUBLE BUS AND DOUBLE BREAKER SYSTEM.

� THE ABOVE CONFIGUARATION IS UTILISED IN 765KV SYSTEM.

� IN THIS SYSTEM EACH CIRCUIT BREAKER HAVING SEPARATE LBB.

� BREAKER FAILURE RELAY OF THE 1-52 CIRCUIT BREAKER TRIPS THE

CONNECTED BUS, 2-52 CIRCUIT BREAKER, AND REMOTE END CIRCUIT

BREAKER.

� SIMILARLY BREAKER FAILURE RELAY OF THE 2-52 CIRCUIT BREAKER

TRIPS THE CONNECTED BUS, 1-52 CIRCUIT BREAKER, AND REMOTE END

CIRCUIT BREAKER.

� INCASE OF TRANSFORMER THE REMOTE END BREAKER MEANS IV

CIRCUIT BREAKER.


BUS-1

1-5

2

3-5

2

5-5

2

-52

-52

OR

(REB 500) ABB (7 SS 52) SIEMENS

1 3 5 7-

9-

BUS-2

2-5

2

4-5

2

6-5

2

8-5

2

10

-52

OR

NEED/NECESSICITYNEED/NECESSICITY

� BUSBAR Protection is provided for high speed sensitive

clearance of BUSBAR faults by tripping all the Circuit

Breakers connected to faulty bus.

� A BUSBAR Protection is a Protection to protect BUSBARs at� A BUSBAR Protection is a Protection to protect BUSBARs at

Short-Circuits and Earth-faults. In the “childhood” of electricity

no separate Protection was used for the BUSBARs. Nearby

line protection were used as back-up for BUSBAR Protection.

� In its absence fault clearance takes place in zone-II of

Distance Relay by remote end tripping.

� With increasing Short-Circuit Power in the network separate

BUSBAR Protections have to be installed to limit the damage

at primary faults. A delayed tripping for BUSBAR faults can

also lead to instability in nearby generators and total system

collapse.

NEED/NECESSICITYNEED/NECESSICITY

� The earliest form of BUS Protection was that provided by

the relays of circuits (i.e. Lines , Transformers, Reactors &

Capacitor Banks) over which current was supplied to a

BUS. In other words the BUS was included within the back-

up zone of these relays. This method was relatively slowup zone of these relays. This method was relatively slow

speed, and loads tapped from the lines would be interrupted

unnecessarily, but it was otherwise effective. Some

preferred this method to one in which the inadvertent

operation of a single relay would trip all the connections to

the BUS.

� This Means Slow And Unselective Tripping And Wide

Spread Black Out.

EFFECT OF DELAYED CLEARENCEEFFECT OF DELAYED CLEARENCE

� Greater damage at fault point.

� Indirect shock to connected equipments like shafts of Generatorand windings of Transformer.

PRINCIPLE OF OPERATIONPRINCIPLE OF OPERATION

� The Principle of Operation of Bus bar protection is Kirchoff’s

Current Law. i.e. Sum of the Currents Entering in to the Node isCurrent Law. i.e. Sum of the Currents Entering in to the Node isequal to Sum of the Currents Leaving the node. Here Node Means

BUSBAR.

CAUSES OF BUS ZONE FAULTSCAUSES OF BUS ZONE FAULTS

� Deterioration of Insulating Material.

� Flashover of insulators due to lightning or

System Over Voltages.System Over Voltages.

� Wrong application of /or failure to remove

temporary earth connections.

� Short circuits caused by birds, monkeys,

vermin and the like.vermin and the like.

� Short circuits caused by construction

machinery.

BASICS OF BUS BAR PROTECTIONBASIC THEORY

EXTERNAL FAULT

KIRCHOFF’s CURENT LAW STATES THAT THE SUM OF THE CURRENTS ENTERING A GIVEN NODE MUST BE EQUAL TO THE CURRENTS LEAVING THAT NODE

INTERNAL FAULTIF

I6

I4

I2

I5

I3

I1

I6

I4

I2

I5

I3

I1

IF

IF

IF= I6= I1+I2+I3+I4+I5 IF= I1+I2+I3+I4+I5+I6

RECOMMENDATIONSRECOMMENDATIONS

� Must have as short tripping time as possible.

� Must be able to detect internal faults.

� Must be absolutely stable at external faults. External faults are

much more common than internal faults. The magnitude ofmuch more common than internal faults. The magnitude of

external faults can be equal to the stations maximum breaking

capacity, while the function currents can go down to

approximately 2% of the same. The stability factor there fore

needs to be at least 50 times i.e. 20. CT-saturation at external

faults must not lead to mal-operation of the BUSBAR

Protection.

� Must be able to detect and trip only the faulty part of the

BUSBAR system.

� Must be secure against mal-operation due to auxiliary contact

failure, human mistakes and faults in the secondary circuits

etc.

TYPES OF BUSBAR PROTECTION SCHEMESTYPES OF BUSBAR PROTECTION SCHEMES

�� HIGHHIGH IMPEDENCEIMPEDENCE BUSBARBUSBAR PROTECTIONPROTECTION:

High Impedance Differential Protection has traditionally been provided by

Electromechanical Relays and associated stabilising resistances connected

across the Current Transformer secondary bus wires of the Protected zone,

i.e. the Measuring Circuit comprises a High impedance stabilising Resistori.e. the Measuring Circuit comprises a High impedance stabilising Resistor

(Metrosil) connected across the circulating current arrangement of all the

CT’s in parallel. The resulting Scheme is economical, simple in concept and

easily extendable to cover additional circuits. It has an added advantage that

low fault current settings can be achieved whilst retaining through fault

stability. Application of this type of scheme can however sometimes be

limited by the need for CTs on each circuit to be of the same ratio and by the

knee point voltage required to achieve fast operating times. The Value ofknee point voltage required to achieve fast operating times. The Value of

Stabilising Resistor chosen such that the voltage drop across the relay circuit

is insufficient to operate the relay for faults outside the protection zone.

The High-impedance protection scheme, on the other hand, is a good

Solution for single BUSBAR arrangements, 1 ½ breaker systems or ring

BUSBARS, providing that appropriate dedicated CT cores are available For

this use alone.

TYPES OF BUSBAR PROTECTION SCHEMESTYPES OF BUSBAR PROTECTION SCHEMES

�� MEDIUM/MODERATE IMPEDENCE BUSBAR PROTNMEDIUM/MODERATE IMPEDENCE BUSBAR PROTN:

This is effectively combination of the normal plain

circulating current High-Impedance and Stabilised

percentage biased differential scheme. This relay actspercentage biased differential scheme. This relay acts

as Medium Impedance Protection during internal faults

& but Low Impedance Protection during load and

external faults.

Although heavy through fault currents may produce a

different current that exceeds the differential pick-up

setting, stabilizing current prevents tripping. Thesetting, stabilizing current prevents tripping. The

requirements made on the primary CT’s are

subsequently less stringent than for a simple High-

Impedance Scheme.

LOW IMPEDANCE PROTECTIONLOW IMPEDANCE PROTECTION

�� PHASEPHASE COMPARISIONCOMPARISION BUSBARBUSBAR PROTECTIONPROTECTION:

This operates on the principle that any BUSBAR fault will becharacterised by all current flows towards the protected BUSBARS

and phase coincidence and is checked for positive and negativehalf cycles. In addition the non coincidence is used for as ahalf cycles. In addition the non coincidence is used for as ablocking signal.

However under low fault level conditions, it is possible for someload flow to continue. To prevent this from stabilising the

Protection, a fault load current of Highest rated outgoing circuit isnormally selected i.e. pick-up level is set above the load current.

The differential current can also be included in the phaseThe differential current can also be included in the phasecomparison , there by further improving stability.

The Main advantage of this scheme is that, it is not necessary forthe current transformers on each circuit to be equal ratio. Also thecurrent transformers may be lower output than those required for

High-Impedance Schemes.

LOW IMPEDANCE BUSBAR PROTECTIONLOW IMPEDANCE BUSBAR PROTECTION

�� PERCENTAGEPERCENTAGE BIASEDBIASED DIFFERENTIALDIFFERENTIAL PROTECTIONPROTECTION:

This Protection is known as current comparison with current

restraint, biased or percentage differential relaying. The operatingcurrent is the Phasor sum of all feeder currents and the restraintcurrent is the arithmetic sum. A trip command is given when

operating current is greater than its pickup level and the stabilisingoperating current is greater than its pickup level and the stabilisingfactor the ratio of operating current to restraint current.

in case of CTs ratios differ, the currents have to be balanced byusing interposing CTs (Aux ratio matching CTs). In this load bias

take care for any matching errors.

where as High-Impedance protection the scheme is inherentlystable during CT saturation, in this scheme special measures muststable during CT saturation, in this scheme special measures mustbe taken to ensure the protection remains stable during CT

saturation. In this scheme check feature can be included.

This type incorporates a stabilising resistor to ensure through fault

stability at high fault levels. This can limit the minimum size ofcurrent transformer that will be required to ensure high speed

performance.

VOLTAGE DIFFERENTIAL RELAY WITH LINEAR COUPLERSVOLTAGE DIFFERENTIAL RELAY WITH LINEAR COUPLERS

The problem of CT saturation is eliminated at its source by air-core CTscalled linear couplers. These CTs are like bushing CTs but they have noiron in their core, and the number of secondary turns is much greater.The secondary-excitation characteristic of these CTs is a straight linehaving a slope of about 5 volts per 1000 ampere-turns.

Contrasted with conventional CTs, linear couplers may be operatedContrasted with conventional CTs, linear couplers may be operatedwithout damage with their secondaries open-circuited. In fact, verylittle current can be drawn from the secondary, because so much of theprimary magneto-motive force is consumed in magnetizing the core.

The linear couplers are connected in a series of all CTs & to Voltage-Differential circuit. For normal load or external-fault conditions, the sumof the voltages induced in the secondaries is zero, except for the verysmall effects of manufacturing tolerances, and there is practically nosmall effects of manufacturing tolerances, and there is practically notendency for current to flow in the Differential Relay.

When a BUS fault occurs, the Voltages of the CTs in all the sourcecircuits add to cause current to flow through all the secondaries and thecoil of the Differential Relay. The Differential Relay, necessarily requiringvery little energy to operate, will provide high-speed Protection for arelatively small net voltage in the Differential Circuit.

SUMMATION CTs METHOD SUMMATION CTs METHOD

In practical application of the schemes, Summation CurrentTransformers (one per main set of CTs) are normally used. Thesesummation CTs have a tapped primary to which the three phasesof the Main CTs are connected, the secondary of the summationCTs providing single-phase output.CTs providing single-phase output.

The Advantages of summation CTs are.

1. Single Relay is used for all three phases.

2. A Definite bias is available for all types external faults.

3. Lead burden on Main CTs is less, provided these CTs arelocated Judiciously.

4. Secondary Cabling is reduced.

5. Aux switch requirement in Double BUSBAR arrangement is5. Aux switch requirement in Double BUSBAR arrangement isreduced.

TheThe MainMain DrawbacksDrawbacks areare

1. The setting for Various types of faults is different, needingcareful analysis.

2. Bias effect is less for Phase faults than for Earth faults.

NUMERICAL BUSBAR PROTECTIONNUMERICAL BUSBAR PROTECTION

� In this two Models of BUSBAR Protections are offered.

1. Centralised Architecture.

2. Distributed Architecture.

� The following are the advantages in this Numerical BUSBAR Protection

1. LBB, EFP and other Protections are inbuilt feature.

2. Ratio Matching Transformers are not required. They can be2. Ratio Matching Transformers are not required. They can beprogrammable.

3. Isolator selection is required and these are to be wired to Bay unit as abinary input & selection relays are not required for zone segregation.

4. One Unit is sufficient, for any no of Zones of BUSBAR Protection.

5. In Distributed Architecture Communication between Bay Unit to CentralUnit is Fiber Optic connection.

6. Check Zone feature like Over-all Differential Protection & Over CurrentStarter Protection is in built function. Recently rate of fall of VoltageStarter Protection is in built function. Recently rate of fall of Voltagefunction also inbuilt function.

7. Current comparison, CT supervision, CT open circuit & CT SaturationDetection is also inbuilt feature.

8. Disturbance Recorder and Event Recorders are inbuilt feature.

9. Distributed Architecture is more convenient, it can be accommodated inrespective Bay C&R Panels and very easy for expansion.

Traditionally Two Distinctive ArchitecturesTraditionally Two Distinctive Architectures((CENTRALISED & DECENTRALISEDCENTRALISED & DECENTRALISED))

52 52 52

Distributed Bus Protection

52 52 52

Centralized Bus Protection

52

DAU

52

DAU

52

DAU

CU

52 52 52

CU

• Fits better new installations

• Perceived less reliable

• Slower

CU

copper

fiber

copper

• Fits better retrofit installations

• Perceived more reliable

• Potentially faster

DIFFERENCE BETWEEN BUSBAR SCHEMES

DETAILS HIGH IMPEDENCE BUSBAR PROTECTIONPERCENTAGE BIASED LOW

IMPEDENCE BUS BAR PROTECTION

PRINCIPLE

THE CURRENTS ENTERING AND LEAVING THE BUSBAR ARECOMPARED CONTINUOSLY. IT INVOLVES CHOOSING OFIMPEDENCE HIGH ENOUGH STABLISE THE RELAY FORHEAVY EXTERNAL FAULTS. THIS IS CIRCULATING CURRENTPRINCIPLE.

IT HAS DIFFERENTIAL AND BIAS SETTING. THERESULTANT BIAS IS PROPOTIONAL TO ARITHMATICSUM OF ALL CURRENTS, WHEREAS THE OPERATINGCURRENT IS VECTOR SUM OF ALL CIRCUITCURRENTS.

IT REQUIRES ALL IDENTICAL CT RATIO’s & TURNS RATIO.LOW RESISTANCE OF SECONDARY WINDING. Class X for

IT CAN WORK WITH CTs OF UNEQUAL RATIOS ALSO.FREE OF ANY NEED OF MATCHED CT

CTs

LOW RESISTANCE OF SECONDARY WINDING. Class X forall CT Cores.MINIMUM KNEE POINT VOLTAGE OF 300-500V.LOWMAGNETISING CURRENT (FEW MILLIAMPS).

FREE OF ANY NEED OF MATCHED CTCHARACTERESTIC OR RATIOs LOW LEAKAGEREACTANCE OR RESISTANCE. OTHER PROTECTIVERELAYS CAN BE INCLUDED IN THE SAME CIRCUIT.

BURDEN

IMPOSES COMPARATIVELY HIGH BURDEN ON CTs.AUXILIARY CTs REDUCE THE PERFORMANCE OF THESCHEME

IMPOSES LESS BURDEN ON CTs. AUXILIARY CTsHAVE NO EFFECT ON PERFORMANCE OF SCHEME.

CT

SATURATION

OPERATION OF SCHEME EVEN WHEN CTs GET SATURATEDDURING INTERNAL FAULTS.

OPERATION OF SCHEME EVEN WHEN CTs GETSATURATED DURING INTERNAL FAULTS. INSENSITIVETO CT SATURATION.

UTILISATION

IT IS GOOD SOLUTION FOR SINGLE BUSBARARRANGEMENTS, ONE & HALF BREAKER SYSTEMS OR RINGBUSBAR SYSTEMS.

MOST SUITABLE FOR DOUBLE AND MULTIPLE BUSBARSYSTEMS ( WITH OR WITHOUT TRANSFER BUS).

OPERATING

TIME

BASIC OPERATING TIME EXCLUDING RELAY TIME IS 15 – 20mS.

DETECTS FAULTS WITH IN 1 –2 mS AND INITIATESTRIPPINGWITH IN 5-7 mS.

STABILITY INABILITY TO COPE WITH INCREASING FAULT CURRENT. STABLE FOR INFINITE FAULT LEVEL.

PERFORMAN

CE

HIGHLY SENSITIVE FOR INTERNAL FAULTS AND COMPLETELYSTABLE FOR EXTERNAL FAULTS.

HIGHLY SENSITIVE FOR INTERNAL FAULTS ANDCOMPLETELY STABLE FOR EXTERNAL FAULTS.

ADDITIONAL

PROTECTION

THIS RELAY REQUIRES CHECK ZONE FEATURE. THE TRIPCOMMAND IS ONLY GIVEN WHEN BOTH ADISCRIMINATING & CHECK ZONE SYSTEM OPERATES.

THIS RELAY HAS IN BUILT CHECK ZONE FEATURE (NOSEPARATE CHECKZONE FEATURE) i.e. OVERCURRENT STARTING RELAY PROVIDED.

CHECK ZONE FEATURECHECK ZONE FEATURE

Mal-operation of BUSBAR Protection can resultin wide spread system failure. It is thereforeconsidered judicious to monitor its operation bysome form of check relay.some form of check relay.

In case of High Impedance Relay the settingcalculations is quite high and some times lowsettings can be adopted. In this factor of safetyis more. This may be possibility for mal-is more. This may be possibility for mal-operation from design point of view. Theprovision of a check feature is therefore purely ameasure against mal-operation caused byexternal agencies.

CHECK ZONE FEATURECHECK ZONE FEATURE

TheThe idealideal checkcheck featurefeature shouldshould possesposses thethe followingfollowing characteristicscharacteristics::

1. Check feature should be provided by a Relay which is physically differentfrom the Main Relay.

2. It should pick-up for all types of faults that the Main Protection is capable ofdetecting.detecting.

3. The check feature should be at least as fast if not faster than MainProtection for given type of fault.

4. The source which feeds the Check Relay should be Physically Differentfrom what feeds the Main Protection.

5. The Check feature should operate only for faults within the Main Zone/Zonesof Protection and not for external faults.of Protection and not for external faults.

6. A separate cores of CTs for Check Relay is added with the ratios same asfor the Main Relay.

7. Check Relay can be connected irrespective of CT isolator selection in caseof Double Bus, Triple Bus & Quad Bus for all circuits, this is called overallCheck zone and in case Single Bus and 1-1/2 CB system same as MainRelay.

TRIPPING LOGICTRIPPING LOGIC

The TRIP command is only given when both a discriminating/Main Zone and Check-Zone system Operates.

To Zone-1 Trip Relays

+ve

Check zone Relay output

Main zone-1 Relay output

To Zone-2 Trip Relays

Main zone-2 Relay output

TRIPPING LOGICTRIPPING LOGIC

incase of Single Bus System and One and Half Breaker system the output ofMain Relay and Check Relay is transferring to Main Tripping Relays & checkTripping Relays respectively. The outputs of these Tripping Relays are

parallel for Tripping and series incase of interlocks.87 BB1

96 BB1

+ve FromDC Source-1

Main zoneRelay output

To Circuit BreakerClosing interlockTrip Coil R-PhTrip Coil Y-PhTrip Coil B-Ph

-ve FromDC Source-1

Check zone Relay output

+ve FromDC Source-2

87 BB2

96 BB2

-ve FromDC Source-2

CBIP Guidelines on ProtectionSPECIAL COMMENTSSPECIAL COMMENTS

i) DC Supply for Bus Bar protection shall be independentfrom feeder.

ii) Faults between CB & CT shall be cleared from one side byopening of CB on Bus Bar Protection Operation.opening of CB on Bus Bar Protection Operation.

iii) However clearing of Fault from other side shall be throughBreaker Failure Protection.

iv) 3–ph trip relays shall be provided for each CB which shallalso initiate LBB/BFR Protection.

v) in case of existing SS where CTs are different ratios, biasedtype Differential Protection/ Numerical Bus Bar Protectionis recommended.is recommended.

vi) Length of secondary leads should be kept as minimum aspossible.

vii)Where lead runs are excessive, an increase in wire size oruse of parallel conductors are meant to reduce leadresistance.

CBIP Guidelines on ProtectionREQUIREMENTSREQUIREMENTS

i. It shall be 3-ph type and operate selectively for each bus bar section.

ii. It shall operate on Differential Principle and provide independent zonesof protection for each bus.

iii. It shall provide zone indication.

iv. It shall be stable for through fault conditions up to maximum 40KA faultiv. It shall be stable for through fault conditions up to maximum 40KA faultlevel.

v. For applications where BUS Differential Protection sensitivity has to beset below load current, as may be a case with use of concretestructures, it is recommended that a separate check zone is provided,other wise separate check zone is not essential. Check zone, if provided,shall be of High Impedance type.

vi. It shall incorporate continuous supervision for CT secondary against anypossible open circuits. In case of detection of open circuiting of CTsecondary, after a time delay, the effected zone of protection shall bepossible open circuits. In case of detection of open circuiting of CTsecondary, after a time delay, the effected zone of protection shall berendered inoperative and alarm initiated.

vii. It shall be include DC supply supervision.

viii. Include adequate number of high speed tripping relays.

ix. whenever CT switching is involved the scheme shall include necessaryCT switching relays and have provision for CT switching incompletealarm.

x. It shall be include IN/OUT switching facility for each zone.

CBIP Guidelines on Protection

� C.T wire supervision relays should be set with a sensitivity suchthat they can detect C.T secondary open circuit even in case ofleast loaded feeder.

� BUSBAR Differential Protection should have overall sensitivity

SETTING CRITERIASETTING CRITERIA

� BUSBAR Differential Protection should have overall sensitivityabove heaviest loaded feeder current unless a separate checkzone has been provided.

� In case where faults currents are expected to be low, theprotection should be sensitive enough to take care of suchexpected low fault current.

� In case of voltage operated High Impedance type Protection, thevoltage setting should be above expected voltage developedvoltage setting should be above expected voltage developedacross the relay during maximum through fault currentcondition.

� In case of current operated relays for stability under throughfault condition, external resistance is to be set such that voltagedeveloped across relay and resistance combination is below thevoltage required for forcing required relay operating current.

HIGH IMPEDENCE BUSBAR PROTECTION

87BBM2

52 CIRCUIT

96 BBM2 : BUSBAR MAIN2 TRIPPING RELAY

52 CIRCUIT BREAKERTRIP COIL

- VEA varistor is normally applied

87BBM1

+ VE96 BBM1 : BUSBAR

MAIN1 TRIPPING RELAY

A varistor is normally applied

across the relay input terminals

to limit the voltage to a value

safely below the insulation

voltage of the secondary circuits

LOW IMPEDENCE BUSBAR PROTECTION

+VE

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TRIPPING

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VOLTAGE-DIFFERENTIAL BUSBAR

PROTECTION

Vd

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SUMMATION CT METHOD

3 3 3 3 3 3 3 3 3 3 3 3

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3 3 3UUUUUUUUU UUUUUUUUU

3 3 3UUUUUUUUU3 3 3

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SUMMATION METHOD DIFFERENTIAL RELAY SUMMATION METHOD DIFFERENTIAL RELAY –– 87BB87BB

UUUUUUUUU UUUUUUUUU UUUUUUUUU UU UUUUUUUUU UU

METHOD - 1 METHOD - 2

DOUBLE BUS- HIGH IMPEDENCEBUS-1

BUS-2

U

UU

UU

UU UU UU

87 B

BC

UU UU UU

87 B

BM

-2

BUS-2

UU

UU

87 B

BM

87 B

BM

-1

ISOLATORSELECTION

ISOLATORSELECTION

ISOLATORSELECTION

ISOLATORSELECTION

DOUBLE BUS- LOW IMPEDENCEBUS-1

BUS-2

U

U

UU UU UU UU

87 B

BM

-2

UU

UU

87 B

BM

87 B

BM

-1ISOLATORSELECTION

ISOLATORSELECTION

ISOLATORSELECTION

ISOLATORSELECTION

LOW IMPEDANCE RELAY HAVING INBUILT CHECK FEATURE

DOUBLE BUS- NUMERICAL CENTRALISEDBUS-1

BUS-2

U

U

UU UU UU UU

UU

UUCENTRALISED NUMERICAL BUSBAR HAVING NUMERICAL ALGORITHAM FORISOLATOR SELECTION, ZONE SELECTION, OVER ALL DIFFERENTAIL PROTECTION ASCHECK ZONE, OVER CURRENT STARTER AS CHECK ZONE, CT SUPERVISION, CT

OPEN CIRCUIT & CT SATURATION ETC FEATURES ARE INBUILT.

87 CENTRALISED NUMERICAL BUSBAR PROTECTION RELAY

DOUBLE BUS- NUMERICAL DISTRIBUTEDBUS-1

BUS-2UU UU UU UU

BUS-2

BAY BAY BAY BAY

UU

87 DISTRIBUTED NUMERICAL BUSBAR PROTECTION RELAY

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

FO FO FO FO

BAY

UNIT

LBB

FO

DOUBLE BUS- DUPLICATE PROTECTIONBUS-1

BUS-2UU UU UU UU

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBBUU

87 DISTRIBUTED

NUMERICAL BUSBAR PROTECTION RELAY

LBB LBB LBB LBB

87 DISTRIBUTED


LBB


BUS-2

UUU

UU UU UU UU

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

UU UU UU UU

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBB

BAY

UNIT

LBBUU

UU

BAY

UNIT

LBB

87 DISTRIBUTED


LBB LBB LBB

87 DISTRIBUTED


LBBLBB LBB LBB LBB LBBLBB


BUS-2

UUUU

UUUU

MAIN2PROT

MAIN1PROT

UU

UU

MAIN1PROT

MAIN2PROT

UU

UU

MAIN1PROT

MAIN2PROT

UU

UU

MAIN1PROT

MAIN2PROT

UU

BAY UNIT

BAY UNIT

BAY UNIT

BAY UNIT

BAY UNIT

BAY UNIT

BAY UNIT

BAY UNIT

87 DISTRIBUTED


87 DISTRIBUTED


BAY UNIT

BAY UNIT

DOUBLE BUS WITH TB- HIGH IMPEDENCEBUS-1

BUS-2

U

UU

UU UU UU UU

UUUU

UU

87BB

UU87BB

CHECK

UU UU UU UU

UU

UU

87BBBUS2

87BBBUS3

87BBBUS1

89A

89B

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

DOUBLE BUS WITH TB- LOW IMPEDENCEBUS-1

BUS-2

U

UU

UU UU UU UU

UUUU

UU

87BB

UU

87BBBUS2

87BBBUS3

87BBBUS1

89A

89B

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

DOUBLE BUS WITH TB- NUMERIC(1)BUS-1

BUS-2

U

UU

UU UU UU UU

UUUU

UUUU

89A

89B

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION

89A

89B

89C

ISOLATORSELECTION


BUS-2

U

UU

UU UU UU UU

UUUU

UUUU

89A

89B

89C

89A

89B

89C

89A

89B

89A

89B

89C

89A

89B

89C

87 BB DISTRIBUTED NUMERICAL BUSBAR

PROTECTION

BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT


BUS-2

U

UU

UU UU UU UU

UUUU

UUUU

89A

89B

89C

89A

89B

89C

89A

89B

89A

89B

89C

89A

89B

89C

87 BB NUMERICAL CENTRALISED BUSBAR

PROTECTION

ONE AND HALF CB SYSTEM – HIGH IMPEDANCE

87BB187BB1--MAIN1 BB1 PROTECTIONMAIN1 BB1 PROTECTION

BUS-1

52

52

52

-52

-52

-52

-52

87BB187BB1--MAIN2 BB1 PROTECTIONMAIN2 BB1 PROTECTION1

-52

2-5

2

1-CT

3-CT

4-5

25

-52

4-CT

6-CT

7-5

28

-52

7-CT

9-CT

10

-11

-52

10-CT

12-CT

13

-1

4-5

2

13-CT

15-CT

16

-1

7-5

2

16-CT

18-CT

19

-2

0-5

2

19-CT

21-CT

UU

UU

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3-5

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3-CT

6-5

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6-CT

9-5

2

9-CT

12

-52

12-CT

15

-52

15-CT

18

-52

18-CT

21

-52

21-CT

87BB287BB2--MAIN1 BB2 PROTECTIONMAIN1 BB2 PROTECTION 87BB287BB2--MAIN2 BB2 PROTECTIONMAIN2 BB2 PROTECTION

UU UU UU UU UU UU UU

ONE AND HALF CB SYSTEM – LOW IMPEDANCE

87 87 –– BB1 BUS BARBB1 BUS BAR--1 PROTECTION1 PROTECTION

BUS-1

52

-52

-52

-52

-52

52

52

1-C

T

7-5

28

-52

7-C

TC

T

10

-11

-52

10

-CT

CT

13

-1

4-5

2

13

-CT

CT

16

-1

7-5

2

16

-CT

CT

19

-2

0-5

2

19

-CT

CT

CT

2-5

21

-52

4-5

25

-52

4-C

TC

T

87 87 –– BB2 BUS BARBB2 BUS BAR--2 PROTECTION2 PROTECTION

BUS-2

9-5

2

9-C

T

12

-52

12

-CT

15

-52

15

- CT

18

-52

18

-CT

21

-52

21

-CT

3-C

T

3-5

2

6-5

2

6-C

T


BUS-1

1-5

2

4-5

2

7-5

2

10

-52

13

-52

OR OR

(REB 500) ABB (7 SS 52) SIEMENS (MICOM P740) AREVA

12

-52

45

-52

78

-52

10

11

-52

13

14

-52

BUS-2

3-5

2

6-5

2

9-5

2

12

-52

15

-52

OR OR

LATEST DEVELOPMENT IN NUMERICAL DISTRIBUTED BUS BAR PROTECTION

ABBABB SIEMENSSIEMENS AREVAAREVA

BUSBAR

PROTECTION

CENTRAL UNIT


c

E

1

2

3

4

9

10

11

12


BAY UNIT

LINE

PROTECTION

TRANSFORMER

21 L1 21 L2 21 L1 21 L2 21 L1 21 L2

C

E



5

6

7

8

13

14

15

16

C

E

PROTECTION

DESCRIPTION

1. IN THIS NO SEPARATE CORE IS REQUIRED FOR EITHER BUSBAR PROTECTION OR LBB / BFR.

2. CENTRALISED BUSBAR IS CONNECTED FROM BAY UNIT OR LBB OR BFR THROUGH FIBRE OPTIC.

3. BAY UNIT / BFR / LBB IS CONNECTED FROM MAIN-1 & MAIN-2 OF LINE PROTECTION OR MAIN &

BACKUP PROTECTION OF TRANSFORMER THROUGH FIBRE OPTIC FOR REDUNDANCY TO BAY UNIT.

4. THE CURRENT DATA IS TRANSFERED TO BAY UNIT TO BUSBAR CENTRAL UNIT FROM LINE /

TRANSFORMER PROTECTIONS FOR NUMIRICAL ALGORITHAM OF LBB & BUSBAR CENTRAL UNIT AND

IT WILL OPERATE FOR INTERNAL FAULTS AND DOES NOT OPERATE FOR THROUGH / EXTERNAL

FAULTS.

87 T1 87 T2 87 T1 87 T2 87 T1 87 T2

C

E

NUMERICAL BUSBAR SCHEME INCL LBB/BFR/CBF

(DECENTRALISED & CENTRALISED ARCHITECTURE)

BU /PUBU /PU

(REB 500) ABB

DECENTRALISED CONCEPTDECENTRALISED CONCEPT CENTRALISED CONCEPTCENTRALISED CONCEPT

FOFO

BU / PUBU / PU

(7 SS 52) SIEMENS

FOFO

(REB 670) ABB

(487B) SEL

OROROROR

BU / PUBU / PU

(MICOM P743) AREVA

LBB INBUILT FEATURELBB INBUILT FEATUREBU / PU TO BUSBARBU / PU TO BUSBAR

DIGITAL COMMUNICATIONDIGITAL COMMUNICATION

FOFO

(MICOM P746) AREVA

LBB INBUILT FEATURELBB INBUILT FEATURE


(DECENTRALISED CONCEPT- DUPLICATE )

BU / PUBU / PU

(REB 500) ABB

DECENTRALISED CONCEPTDECENTRALISED CONCEPT

FOFO(REB 500) ABB

DECENTRALISED CONCEPTDECENTRALISED CONCEPT

BU / PUBU / PU

FOFO

BU / PUBU / PU

OR

OR

(7 SS 52) SIEMENSFOFO

OR

OR

(7 SS 52) SIEMENS

BU / PUBU / PU

BU / PUBU / PU

FOFO

BU / PUBU / PU

OR

(MICOM P743) AREVA

BU / PU TO BUSBARBU / PU TO BUSBARDIGITAL COMMUNICATIONDIGITAL COMMUNICATION

FOFO

OR

(MICOM P743) AREVA

BU / PU TO BUSBARBU / PU TO BUSBARDIGITAL COMMUNICATIONDIGITAL COMMUNICATION

BU / PUBU / PU

FOFO

LBB INBUILT FEATURELBB INBUILT FEATURE LBB INBUILT FEATURELBB INBUILT FEATURE


(CENTRALISED CONCEPT - DUPLICATE)

CENTRALISED CONCEPTCENTRALISED CONCEPT CENTRALISED CONCEPTCENTRALISED CONCEPT

(REB 670) ABB

(487B) SEL

(REB 670) ABB

(487B) SEL

LBB INBUILT FEATURELBB INBUILT FEATURE LBB INBUILT FEATURELBB INBUILT FEATURE

(MICOM P746) AREVA

(MICOM P746) AREVA

PROTECTION OF RING BUS SYSTEM

UU UU

87

BB

2

87 BB3FEEDER4 FEEDER3

UU

UU8

7 B

B2

87

BB

4

UU

UU

UU UU

FEEDER187 BB1

FEEDER2

87

BB

4

BUS BAR PROTECTION

INITIATE ALL CBs TRIP UNITS CONNECTED TO THIS BUS AND OPERATE.

TO TRIP COIL-1 CONCERNED BAY CB


TO CLOSE CIRCUIT INTERLOCK OF CONCERN CB

DIRECT TRIP SEND CHANNEL-1 TO OTHER END


BU

SB

US

--1

1

TO EVENT RECORDER ( SOE/ SCADA )

TO DISTURBANCE RECORDER OF MAIN-1

INITIATE ALARM (ANNUNCIATION COME)

TO LBB/BFR INITIATION


FROM LBB/BFR TO BUS BAR TRIPPING

INITIATE ALL CBs TRIP UNITS CONNECTED TO THIS BUS AND OPERATE.



BU

SB

US

TO EVENT RECORDER ( SOE/ SCADA )



TO CLOSE CIRCUIT INTERLOCK OF CONCERN CB



INITIATE ALARM (ANNUNCIATION COME)

TO LBB/BFR INITIATION


FROM LBB/BFR TO BUS BAR TRIPPINGBU

SB

US

--2

2

87 BUSBAR PROTECTION TRIPPING SCHEME87 BUSBAR PROTECTION TRIPPING SCHEME

HIGH SPEEDHIGH SPEED

TRIP RELAYTRIP RELAY

(96BB) FOR (96BB) FOR

BAY1BAY1



(96BB) FOR (96BB) FOR

BAY2BAY2

BAY1 CR PANELBAY1 CR PANEL

TRIP FROM 50 LBB

TO START 50 LBB

BAY2 CB PANELBAY2 CB PANEL

TRIP FROM 50 LBB

TO START 50 LBB

FO

R S

ING

LE

BU

S S

YS

TE

MBAY2BAY2



(96 BB) FOR (96 BB) FOR

BAY3BAY3




BAY4BAY4

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

87 BUSBAR

FO

R S

ING

LE

BU

S S

YS

TE

M



(96BB)FOR (96BB)FOR

BAY5BAY5




BAY6BAY6

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

+VE BUSBAR PANEL

FO

R S

ING

LE

BU

S S

YS

TE

M

96 BB (MASTER TRIP RELAY) OPERATION96 BB (MASTER TRIP RELAY) OPERATION

87 BUSBAR

TO D/T-1

+VE

-VERESET

OPERATED

PB

FO

R S

ING

LE

BU

S S

YS

TE

M,

ON

E &

HA

LF

CB

SY

ST

EM

,D

OU

BL

E C

B &

DO

UB

LE

BU

S S

YS

TE

M

& R

ING

MA

IN B

US

SY

TE

M

TO D/T-1

TO CL I/L

TO LBB

TO TC-1

TO D/T-2

TO ANNUN

TO SER

FROM LBB

FO

R S

ING

LE

BU

S S

YS

TE

M,

ON

E &

HA

LF

CB

SY

ST

EM

,D

OU

BL

E C

B &

DO

UB

LE

BU

S S

YS

TE

M

& R

ING

MA

IN B

US

SY

TE

M

TO TC-2

TO M1 DR

TO M2 DR


FO

R S

ING

LE

BU

S S

YS

TE

M,

ON

E &

HA

LF

CB

SY

ST

EM

,D

OU

BL

E C

B &

DO

UB

LE

BU

S S

YS

TE

M

& R

ING

MA

IN B

US

SY

TE

M

96 BB (MASTER TRIP RELAY) OPERATION96 BB (MASTER TRIP RELAY) OPERATION

TO D/T-1

+VE

-VERESET

OPERATED

PB

FO

R S

INL

E B

US

AN

D T

RA

NS

FE

R B

US

SY

ST

EM

FO

R D

OU

BL

E B

US

SY

ST

EM

FO

R D

OU

BL

E B

US

& B

YP

AS

S I

SO

SY

ST

EM

DO

UB

LE

BU

S &

TR

AN

SF

ER

BU

S S

YS

TE

M

TR

IPP

LE

BU

S &

TR

AN

SF

ER

BU

S S

YS

TE

M &

(DO

UB

LE

BU

S W

ITH

CB

SE

CT

ION

AL

ISE

R)

BUSBARRELAYS

ISOLATORSELECTION

87 A 89 A

87 B 89 B TO D/T-1

TO CL I/L

TO LBB

TO TC-1

TO D/T-2

TO ANNUN

TO SER

IF BUS-1 IS OPERATED THE FEEDERS CONNECTED TO BUS BAR-1WILL BE OPTD BASED ON

FO

R S

INL

E B

US

AN

D T

RA

NS

FE

R B

US

SY

ST

EM

FO

R D

OU

BL

E B

US

SY

ST

EM

FO

R D

OU

BL

E B

US

& B

YP

AS

S I

SO

SY

ST

EM

DO

UB

LE

BU

S &

TR

AN

SF

ER

BU

S S

YS

TE

MT

RIP

PL

E B

US

SY

TE

MT

RIP

PL

E B

US

& T

RA

NS

FE

R B

US

SY

ST

EM

&

QU

AD

BU

S S

YT

EM

(DO

UB

LE

BU

S W

ITH

CB

SE

CT

ION

AL

ISE

R)

FROM LBB

87 B 89 B

87 C 89 C

TO TC-2

TO M1 DR

TO M2 DR


BAR-1WILL BE OPTD BASED ON

THE ISOLATOR SELECTION. SIMILARLY FOR BUS-2 & BUS-3 & FOR ANY NO OF BUSES, EXCEPT 1.ONE AND HALF CB SYSTEM,2.DOUBLE CB SYSTEM & 3.RING BUS SYTEM. FO

R S

INL

E B

US

AN

D T

RA

NS

FE

R B

US

SY

ST

EM

FO

R D

OU

BL

E B

US

SY

ST

EM

FO

R D

OU

BL

E B

US

& B

YP

AS

S I

SO

SY

ST

EM

DO

UB

LE

BU

S &

TR

AN

SF

ER

BU

S S

YS

TE

MT

RIP

PL

E B

US

SY

TE

MT

RIP

PL

E B

US

& T

RA

NS

FE

R B

US

SY

ST

EM

&

QU

AD

BU

S S

YT

EM

(DO

UB

LE

BU

S W

ITH

CB

SE

CT

ION

AL

ISE

R)

87BB87BB--1 BUSBAR PROTECTION TRIPPING SCHEME1 BUSBAR PROTECTION TRIPPING SCHEME

HIGH SPEED

TRIP RELAY

(96BB) FOR

BAY1

HIGH SPEED

TRIP RELAY

(96BB) FOR

BAY4


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

FO

R O

NE

& H

AL

F C

IRC

UIT

BR

EA

KE

R S

YS

TE

M

BAY4

HIGH SPEED

TRIP RELAY

(96 BB) FOR

BAY7

HIGH SPEED

TRIP RELAY

(96 BB) FOR

BAY10

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

87 BUSBAR

FO

R O

NE

& H

AL

F C

IRC

UIT

BR

EA

KE

R S

YS

TE

M

87 BB-1

HIGH SPEED

TRIP RELAY

(96BB)FOR

BAY13

HIGH SPEED

TRIP RELAY

(96 BB) FOR

BAY16

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

+VE BUSBAR PANEL

FO

R O

NE

& H

AL

F C

IRC

UIT

BR

EA

KE

R S

YS

TE

M

87BB87BB--2 BUSBAR PROTECTION TRIPPING SCHEME2 BUSBAR PROTECTION TRIPPING SCHEME

HIGH SPEED

TRIP RELAY

(96BB) FOR

BAY3

HIGH SPEED

TRIP RELAY

(96BB) FOR

BAY6


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

FO

R O

NE

& H

AL

F C

IRC

UIT

BR

EA

KE

R S

YS

TE

M

BAY6

HIGH SPEED

TRIP RELAY

(96 BB) FOR

BAY9

HIGH SPEED

TRIP RELAY

(96 BB) FOR

BAY12

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

87 BUSBAR

FO

R O

NE

& H

AL

F C

IRC

UIT

BR

EA

KE

R S

YS

TE

M

87 BB-2

HIGH SPEED

TRIP RELAY

(96BB)FOR

BAY15

HIGH SPEED

TRIP RELAY

(96 BB) FOR

BAY18

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB


TRIP FROM 50 LBB

TO START 50 LBB

+VE BUSBAR PANEL

FO

R O

NE

& H

AL

F C

IRC

UIT

BR

EA

KE

R S

YS

TE

M

UTILISATION RECOMMENDATIONSUTILISATION RECOMMENDATIONS

� BUSBAR protection must be provided in all new 400kVand 220kV Substations as well as Generating StationSwitchyards.

� For existing Substations, provision of BUSBAR Protectionis must & considered at 400kV level and at 220kV level.is must & considered at 400kV level and at 220kV level.

� In case of radially fed 220kV Substations, having morethan one bus it is desirable to have BUSBAR Protection,but it is an Option.

� Redundant / Duplicate Busbar Protection to be providedFor Substations of High strategic importance i.e. 765KVor 400KV Systems.or 400KV Systems.

� Dedicated Protections invariably employ separate DCcircuits and CT cores. They send trip impulses toseparate trip coils and use separate isolator positionauxiliary contacts. Cross tripping of both trip coils is alsodone.

DISTRIBUTED ARCHITECTURE DISTRIBUTED ARCHITECTURE (CONNECTION DIAGARAM)(CONNECTION DIAGARAM)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16


1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16


BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT

PERIPHERALUNITS

BAYUNIT

BAYUNIT

C

E


ABB Network Partner AG REL 316*4 ABB Network Partner AG REL 316*4

C

E

C

E

CE

NT

RA

LU

NIT

S

CE

NT

RA

LU

NIT

S

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

C

E

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

C

E

BAYUNIT

BAYUNIT

BAYUNIT

BAYUNIT

PERIPHERALUNITS

BAYUNIT

BAYUNIT

STAR CONNECTION TOPOLOGYSTAR CONNECTION TOPOLOGY

TOSHIBA Bay unit is accepting 2Bays in one. So One Bay unit is for one Dia or 2 Adjacent Bays

DISTRIBUTED ARCHITECTURE DISTRIBUTED ARCHITECTURE (CONNECTION DIAGARAM)(CONNECTION DIAGARAM)

Tx

Rx

Tx

Tx

Rx

Tx

Tx

Rx

Tx

Tx

Rx

Tx

RxRx Rx Rx

Tx

Rx

Tx

Tx

Rx

Tx

Tx

Rx

Tx

Tx

Rx

TxTx

Rx

Tx

Rx

Tx

Rx

Tx

Rx

REDUNDANT RING TOPOLOGYREDUNDANT RING TOPOLOGY

FUNCTIONS OF DISTRIBUTED BUSBAR BAY UNIT BAY UNIT

FUNCTIONS & PROTECTIONSFUNCTIONS & PROTECTIONS

CENTRAL UNIT CENTRAL UNIT

FUNCTIONS & PROTECTIONSFUNCTIONS & PROTECTIONS

1. Breaker Failure Protection (LBB)

2. End Fault Protection (EFP)

3. Over Current Protection (OC)

1. Breaker Failure Protection (LBB)

2. Neutral Current Detection (Io)

3. Disturbance Recorder (DR)3. Over Current Protection (OC)

4. Pole Discrepancy Protection (PD)

5. Under Voltage Protection (U)

6. Disturbance Recorder (DR)

7. Event Recorder (ER)

8. Fault Recorder (FR)

9. Alarms

3. Disturbance Recorder (DR)

4. Event Recorder (ER)

5. Fault Recorder (FR)

6. Alarms

7. Programmable LEDs

8. Communication to BU

(Owner Based Protocol)9. Alarms

10. Programmable LEDs

11. Human Machine Interface (HMI)

12. Measurements

13. Communication to CU (Owner Based Protocol)

9. Communication to SAS

(IEC 61850 Protocol)

10. Check Zone Busbar

11. Remote HMI

12. Measurements

13. Test Generator

BENEFITS OF DISTRIBUTED BUSBAR 1. Improved Functionality – Optional

Functions.

2. Less Space Required – Aux relays

not required for Isolator selection.

3. We can save the 96 Relay – Thiscan be possible to configure in Bay

11. On Line Alarms.

12. On Line Event Lists.

13. Ethernet Connection (TCP/IP).

14. Connection to SAS/SCS.

15. Disturbance Recorder Transfer.can be possible to configure in Bay

Unit.

4. Easily Expandable.

5. Reduced Copper Wiring – Savingof cable 60%.

6. Software CT matching.

7. Reduced no of Spare parts – Aux

15. Disturbance Recorder Transfer.

16. Data Archiving (Disturbance / Events).

17. Access to Remote Disturbance

data.

18. Disturbance Analysis.

19. Synchronous System events.

20. Remote Support.7. Reduced no of Spare parts – Aux

CTs and CT switching Relays.

8. Easy changeable parameters at

site.

9. Continuous self Supervision.

10. Less Cost for Maintenance.

20. Remote Support.

21. Signal Simulation.

22. Upgrading functionality.

23. Measurement in BU & CU.

TYPES OF BUSBAR PROTECTION RELAYSDISTRIBUTED ARCHITECTURE CENTRALISED ARCHITECTURE

MAKE MODEL BAY UNIT CENTRAL UNIT MAKE MODEL CENTRAL UNIT

ABBREB

500ABB

REB

670C


1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16


C

500 670

AREVAMICOM

P 741/3AREVA

MICOM

P 746

SIEMENSSIPROTEC

7 SS 52GE

UR

B 90

EE

B 90

ANDRITZDRS

BBSEL

SEL

487 B

HITACHIGRB

100

ERL

PHASE

B-PRO

4000

RECOMMENDATIONS FOR 400KVRECOMMENDATIONS FOR 400KV

� In Case of Centralised Architecture BUSBAR

Protection, Stand alone LBB is preferable.

� In Case of Distributed Architecture BUSBAR

Protection, LBB is configured in Bay Unit,Protection, LBB is configured in Bay Unit,

BUSBAR Protection is configured in Central

Unit and tripping Logic is to be duplicated i.e.

one tripping Logic Through FO and another

through Hardwiring.

� In case of Redundant or Duplicate BUSBAR� In case of Redundant or Duplicate BUSBAR

Protection Distributed Architecture need not

require redundant/ Duplicate trip logic. The

Tripping Logic from CU to BU is FO and BU to

Master trip Relay & Trip Coil.

MODIFICATIONS REQUIRED IN DISTRIBUTED BUSBAR MODIFICATIONS REQUIRED IN DISTRIBUTED BUSBAR

� The Connection between BU & CU Redundant

communication.

� Bay Unit can communicate to Dual/ Twin CUs in

Star Topology.

� The Connection between BU & CU Redundant and

one is Star Topology communication and another is

Redundant Ring Topology Communication.

� Always Preferable Fail Safe Mode.

� When ever FO Communication Problem, CU is giving

Alarm and BB is blocked (out of service). This can beAlarm and BB is blocked (out of service). This can be

modified. The value before failure has to be taken

and BB is to be in service. Now a days all Relays are

61850 Communication, when failure, the Analog data

from Main Relays and Digital Data from BCU and

tripping can be extend through BCU / Main Relays.

LBB & BUSBAR

Documents

circuit breaker failure

associated circuit breaker

faulty circuit breaker

appropriate circuit

feeder protection

protection relays

singlestage protection

faulted breaker