BREAKER FAILURE PROTECTION - etouches · PDF fileBreaker Failure Protection 30th Annual Hands‐On Relay School March 11 ‐15, 2013 Brent Carper, PE Engineering Manager Relay Application

Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013

Brent Carper, PEEngineering Manager

Relay Application Innovation, Inc.

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Brent Carper, PEEngineer ing Manager

brent .c@relayappl icat ion.com

BREAKER FAILURE PROTECTION

30th Annual

HANDS-ONRELAY SCHOOL

March 11 - 15, 2013

Protection System Failures and Breaker Failures

BF Protection versus BF Relaying

BF Relay Schemes and Logic

Special BF Situations

BF Setting Calculation Exercise

Impacts from Changing Technology

Testing and Maintenance of BF Schemes

Primar y Reference:

C37.119 -2005 IEEE Guide for Breaker Fai lure Protect ion of Power C i rcuit Breakers

OUTLINE




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Protection System Failures Relay fai lure

Settings fai lure

Control system fai lure

CT/PT fai lure

Battery system fai lure

Catastrophic control house fai lure (fire)

Breaker Failures Fails to tr ip

Trips too slow

Fails to interrupt fault current

Fails to interrupt load current

Flashover when open

Fails to close

Auxil iary contact problems

Catastrophic fai lure

PROTECTION FAILURE

Breaker Failure Protection

versus

Breaker Failure Relaying




3

BREAKER FAILURE PROTECTIONBY COORDINATION

T A B


T A B




4


T A B

Advantages: Simple – No ext ra equipment

Simple – No r isk of misoperat ion

Ul t imate protect ion. Covers ALL fa i lures , not just Breaker Fai lure ( fa i lure of breaker, re lay, set t ings, cont rols and wi r ing , bat ter y, etc . )

Disadvantages: Slow

May not be poss ible for the backup re lay ing at [A ] to see a l l faul ts


Conclusions: Common pract ice for D is tr ibut ion, but typ ical ly not suf f ic ient for Transmiss ion.

There is “Breaker Fa i l Protect ion” even though there is not “Breaker Fa i l Re lay ing” .

Breaker fa i lure protect ion is bui l t - in to good protect ion pract ices.

T A B




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[A ] can probably back up [B] and see a minimum faul t a l l the way at the end of the l ine .

[M] may not be able to fu l ly back up the feeder breakers for an end of l ine faul t .

E x a m p l e : A s s u m e 2 0 0 A l o a d p e r f e e d e r s e c t i o n , a n d 8 0 0 A m i n i m u m f a u l t c u r r e n t a t t h e e n d o f l i n e .

[ A ] h a s 4 0 0 A m a x l o a d a n d n e e d s t o p i c k u p o n a n 8 0 0 A f a u l t .

[ M ] h a s 1 0 0 0 A m a x l o a d , s o i t c a n n o t b e s e t t o p i c k u p o n a n 8 0 0 A f a u l t .


T A B

T

2

3

4

5

M

1

IEEE EXAMPLE

1A 2 5

3

7 8

4

6 C

Load

Load

Load

A

B C




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IEEE EXAMPLEPROPER CLEARING

1A 2 5

3

7 8

4

6 C

Load

Load

Load

A

B C

IEEE EXAMPLEBREAKER FAILURE

1A 2 5

3

7 8

4

6 C

Load

Load

Load

A

B C




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IEEE EXAMPLEREMOTE BACKUP

1A 2 5

3

7 8

4

6 C

Load

Load

Load

A

B C

Advantages: Complete ly independent of

Substat ion B .

Disadvantages: Slow – system instabi l i ty

Slow – vo l tage d ips

Wide area outage

May not be poss ible for the backup re lay to see a l l fau l ts

IEEE EXAMPLEBREAKER FAILURE RELAYING

1A 2 5

3

7 8

4

6 C

Load

Load

Load

A

B C




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IEEE EXAMPLEBREAKER FAILURE RELAYING

1A 2 5

3

7 8

4

6 C

Load

Load

Load

A

B C

BFR on breaker [3] detects breaker failure condition

BFR t r ips a Lockout re lay

Lockout re lay (86) t r ips breakers [2 ] , [5 ] , and [7 ]

Lockout re lay b locks c lose of [2 ] , [5 ] , and [7 ]

What else?

Transfer Tr ip to breaker [4 ]

Cancel rec lose of [4 ]

BREAKER FAILURE RELAYING

21Z1

5062

86BF

21Z2

87B

86B

BFI

21Z2

67G

67G

01

trip allbkrs on bus

trip alladjacent bkrs

DTT/RC toremote bkrs




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21P

5062

86BF

21B

87B

86BBFIBFI

BF

I


21B

87B

21P

21B

21P

87B

BF1

BF2

BF3

1 2 3




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1. Basic Breaker Failure Scheme

2. 50BF Torque Control

3. Breaker Re-Trip Logic

4. BFI Control Timer

5. BFI Seal- In

6. Minimal Current Scheme

7. Timer Bypass Scheme

8. Dual Timer Scheme

9. Special Schemes

BREAKER FAILURE LOGIC

BASIC BREAKER FAILURE SCHEME

Four Parts to a Breaker Failure Scheme: Fault Detector (50) or other Failure Detectors

Initiator Circuit (BFI)

Logic and Timers (62)

Output Circuit (BFT)




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50BF TORQUE CONTROL

BREAKER RE-TRIP LOGIC




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BFI CONTROL TIMER

BFI SEAL-IN




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MINIMAL CURRENT SCHEME

TIMER BYPASS SCHEME

N o t e : T h i s l o g i c i s f o r i l l u s t r a t i v e p u r p o s e s o n l y . N o t i n t e n d e d a s a c o m p l e t e s c h e m e . T h e t i m e r b y p a s s s c h e m e s h o u l d b e s u p e r v i s e d b y a f a u l t d e t e c t o r , w h i c h m a y n o t b e c o m p a t i b l e w i t h t o r q u e c o n t r o l l e d 5 0 B F .




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EXAMPLE BE1-50BF LOGIC

Use fast BF timer for multi -phase faults (L-L, L-L-G, 3P)

Use slower BF timer for single-phase faults (SLG)

Multi-phase faults have larger impact on system stabil ity, and may require fast breaker failure t imes.

Single-phase faults are more common.

Dual t imer allows fast BFT for the multi -phase fault, but keeps the security of a slower BFT for the most common fault scenario.

DUAL TIMER SCHEMES




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Voltage dif ferential

Frame leakage detection

Breaker dif ferential

IPO breakers

Redundant breakers

SPECIAL SCHEMES

Logic

Fault or Load Current Detector Pickup

Other Breaker Failure Detectors

Set Timers

BF SETTINGS




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CALCULATING BF SCHEME TIMERS

MARGIN

BF TIMERSETTING

CONTROL TIMERSETTING

REMOTE END BACKUP BREAKEROPERATE TIME

TTCHANNELTIME

BFROUTPUT

RELAYTIME

50FDP/U

BFIINPUT

P/U

MAX CRITICAL CLEARING TIM

EBY COMPANY POLICY

CRITICAL CLEARING TIM

ECALCULATED BY STUDY

86BFOPERATE

TIME

LOCAL BACKUP BREAKEROPERATE TIME

FAULT

PROTECTIVE RELAYOPERATE TIME

BREAKEROPERATE TIME

NORMAL CLEARING TIME

50FDRESET

PROPER

OPER

ATION

FAULT CLEARED

Digital Relay BF Protection: Faster, Better, Cheaper, More Solved transient stability problems previously unsolvable

Better protection against wide-area and cascading outages

Protect against all breaker failure modes, not just one or two

Can be more secure if designed well

Most uti l ities moving away from Stand-Alone BF Relays Some utilities (not many) are reversing the trend and going back to stand alone

Breaker Failure Relays

Reduce misoperations “unscheduled maintenance tests”

Use longer maintenance cycles for BF protection systems

IMPACT OF CHANGING TECHNOLOGY




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21P

BF

86BF

21B

87B

86BBFIBFI

BF

I


21P

BF

86BF

21B

87B

86BBFI

BF

I

BF

BF

I




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21P

BF

86BF

21B

87B

86BBFI

BFI

BF


21P

BF

86BF

21B

87B

86B

BFI

BF

I

BF

BF

I

BF




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21B

87B

21P

21B

21P

87B

BF1

1 2 3

BF1

BF3

BF2

BF2

BF2

BF2

BF3

BF3

BF1

Digital Relay Timing and Logic Precise timing eliminates relay misoperations due to calibration drift

Precise timing and logic allows reducing “design margins”

Digital Relay I/O Sensitive BFI inputs (transients, DC grounds)

Solid state relay outputs (sneak circuits)

Digital Relay Protective Elements Used to be limited to a 50FD

Now we can use 50L and other sensitive detectors that may pick up a lot

Solution: Consider using other elements to help add Security, not just Sensitivity(negative sequence, voltage elements, synch check and frequency elements, etc.)





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Challenges from Complexity Elaborate/exotic BF logic

Wide variety of BF schemes, even in the same model of relay at the same utility

May have more than one BF scheme in a single relay

May have more than one BF scheme for single breaker

Solution: Engineering Standardization

Solution: Documentation (written setting descriptions, logic diagrams, and test plans)

Challenges with Integrated BF May not be able to disable all BFI’s

May not be able to disable all BFT’s

Trend is to completely eliminate all hardwired BFT and lockout relays (IEC 61850)

Solution: Design with test switch to relay input that disables the BFI and/or BFT. Especially important for BFTT or 61850.


Challenges with BF Protection Dif f icu l t to test intent ional ly

Easy to test unintent ional ly

TESTING AND MAINTENANCEOF BREAKER FAILURE PROTECTION




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There is a dif ference between testing the BF Relay

and testing the BF Relaying System

Many ut i l i t ies per form maintenance test ing of the BF Relay, but are not test ing the ent i re Breaker Fai lure Protect ion System.

Good maintenance pract ices (and NERC compl iance requirements ) are to test the Protect ion System:

Maintenance program for the BF Relay

Maintenance program for CT’s/PT’s

Maintenance program for the Battery and DC system

Maintenance of the BFR Protection System must include: Rolling lockout relays and tripping breakers

Best practice: simultaneous functional test (clear the bus)

TESTING AND MAINTENANCEOF BREAKER FAILURE PROTECTION

Brent CarperProtection & Integration [email protected]

BREAKER FAILURE PROTECTION

Brent Carper, PEEngineering [email protected]

Documents

BREAKER FAILURE PROTECTION - etouches · PDF fileBreaker Failure Protection 30th Annual Hands‐On Relay School March 11 ‐15, 2013 Brent Carper, PE Engineering Manager Relay Application