Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
1
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
2
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
3
BREAKER FAILURE PROTECTIONBY COORDINATION
T A B
BREAKER FAILURE PROTECTIONBY COORDINATION
T A B
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
4
BREAKER FAILURE PROTECTIONBY COORDINATION
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
BREAKER FAILURE PROTECTIONBY COORDINATION
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
5
[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 .
BREAKER FAILURE PROTECTIONBY COORDINATION
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
6
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
7
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
8
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
9
BREAKER FAILURE RELAYING
21P
5062
86BF
21B
87B
86BBFIBFI
BF
I
BREAKER FAILURE RELAYING
21B
87B
21P
21B
21P
87B
BF1
BF2
BF3
1 2 3
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
10
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)
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
11
50BF TORQUE CONTROL
BREAKER RE-TRIP LOGIC
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
12
BFI CONTROL TIMER
BFI SEAL-IN
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
13
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 .
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
14
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
15
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
16
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
17
IMPACT OF CHANGING TECHNOLOGY
21P
BF
86BF
21B
87B
86BBFIBFI
BF
I
IMPACT OF CHANGING TECHNOLOGY
21P
BF
86BF
21B
87B
86BBFI
BF
I
BF
BF
I
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
18
IMPACT OF CHANGING TECHNOLOGY
21P
BF
86BF
21B
87B
86BBFI
BFI
BF
IMPACT OF CHANGING TECHNOLOGY
21P
BF
86BF
21B
87B
86B
BFI
BF
I
BF
BF
I
BF
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
19
IMPACT OF CHANGING TECHNOLOGY
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.)
IMPACT OF CHANGING TECHNOLOGY
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
20
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.
IMPACT OF CHANGING TECHNOLOGY
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
Breaker Failure Protection30th Annual Hands‐On Relay SchoolMarch 11 ‐ 15, 2013
Brent Carper, PEEngineering Manager
Relay Application Innovation, Inc.
21
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]