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3
CIRCUIT BREAKER FAIL IMPLEMENTATION
Circuit Breaker Failure Protection is implemented in the CB FAIL & P.DEAD column of the relevant settings group.
3.1
CIRCUIT BREAKER FAIL TIMERS
The circuit breaker failure protection incorporates two timers, CB Fail 1 Timer and CB Fail 2 Timer, allowing
configuration for the following scenarios:
●
Simple CBF, where only CB Fail 1 Timer is enabled. For any protection trip, the CB Fail 1 Timer is started, and
normally reset when the circuit breaker opens to isolate the fault. If breaker opening is not detected, the CB
Fail 1 Timer times out and closes an output contact assigned to breaker fail (using the programmable
scheme logic). This contact is used to back-trip upstream switchgear, generally tripping all infeeds
connected to the same busbar section.
●
A retripping scheme, plus delayed back-tripping. Here, CB Fail 1 Timer is used to issue a trip command to a
second trip circuit of the same circuit breaker. This requires the circuit breaker to have duplicate circuit
breaker trip coils. This mechanism is known as retripping. If retripping fails to open the circuit breaker, a
back-trip may be issued following an additional time delay. The back-trip uses CB Fail 2 Timer, which was
also started at the instant of the initial protection element trip.
You can configure the CBF elements CB Fail 1 Timer and CBF Fail 2 Timer to operate for trips triggered by
protection elements within the device. Alternatively you can use an external protection trip by allocating one of the
opto-inputs to the External Trip DDB signal in the PSL.
You can reset the CBF from a breaker open indication (from the pole dead logic) or from a protection reset. In these
cases resetting is only allowed if the undercurrent elements have also been reset. The resetting mechanism is
determined by the settings Volt Prot Reset and Ext Prot Reset.
The resetting options are summarised in the following table:
Initiation (Menu Selectable)
CB Fail Timer Reset Mechanism
Current based protection
The resetting mechanism is fixed (e.g. 50/51/46/21/87)
IA< operates AND IB< operates AND IC< operates AND IN< operates
Sensitive Earth Fault element
The resetting mechanism is fixed.
ISEF< Operates
Non-current based protection (e.g. 27/59/81/32L)
Three options are available:
●
All I< and IN< elements operate
●
Protection element reset AND all I< and IN< elements operate
●
CB open (all 3 poles) AND all I< and IN< elements operate
External protection
Three options are available.
●
All I< and IN< elements operate
●
External trip reset AND all I< and IN< elements operate
●
CB open (all 3 poles) AND all I< and IN< elements operate
3.2
ZERO CROSSING DETECTION
When there is a fault and the circuit breaker interrupts the CT primary current, the flux in the CT core decays to a
residual level. This decaying flux introduces a decaying DC current in the CT secondary circuit known as
subsidence current. The closer the CT is to its saturation point, the higher the subsidence current.
The time constant of this subsidence current depends on the CT secondary circuit time constant and it is generally
long. If the protection clears the fault, the CB Fail function should reset fast to avoid maloperation due to the
subsidence current. To compensate for this the device includes a zero-crossing detection algorithm, which ensures
that the CB Fail re-trip and back-trip signals are not asserted while subsidence current is flowing. If all the samples
within half a cycle are greater than or smaller than 0 A (10 mS for a 50 Hz system), then zero crossing detection is
asserted, thereby blocking the operation of the CB Fail function. The zero-crossing detection algorithm is used
P54A/B/C/E
Chapter 8 - CB Fail Protection
P54xMED-TM-EN-1
185
Содержание P4A
Страница 2: ......
Страница 20: ...Contents P54A B C E xviii P54xMED TM EN 1 ...
Страница 27: ...CHAPTER 1 INTRODUCTION ...
Страница 28: ...Chapter 1 Introduction P54A B C E 2 P54xMED TM EN 1 ...
Страница 38: ...Chapter 1 Introduction P54A B C E 12 P54xMED TM EN 1 ...
Страница 39: ...CHAPTER 2 SAFETY INFORMATION ...
Страница 40: ...Chapter 2 Safety Information P54A B C E 14 P54xMED TM EN 1 ...
Страница 52: ...Chapter 2 Safety Information P54A B C E 26 P54xMED TM EN 1 ...
Страница 53: ...CHAPTER 3 HARDWARE DESIGN ...
Страница 54: ...Chapter 3 Hardware Design P54A B C E 28 P54xMED TM EN 1 ...
Страница 86: ...Chapter 3 Hardware Design P54A B C E 60 P54xMED TM EN 1 ...
Страница 87: ...CHAPTER 4 SOFTWARE DESIGN ...
Страница 88: ...Chapter 4 Software Design P54A B C E 62 P54xMED TM EN 1 ...
Страница 99: ...CHAPTER 5 CONFIGURATION ...
Страница 100: ...Chapter 5 Configuration P54A B C E 74 P54xMED TM EN 1 ...
Страница 120: ...Chapter 5 Configuration P54A B C E 94 P54xMED TM EN 1 ...
Страница 121: ...CHAPTER 6 CURRENT DIFFERENTIAL PROTECTION ...
Страница 122: ...Chapter 6 Current Differential Protection P54A B C E 96 P54xMED TM EN 1 ...
Страница 149: ...CHAPTER 7 AUTORECLOSE ...
Страница 150: ...Chapter 7 Autoreclose P54A B C E 124 P54xMED TM EN 1 ...
Страница 207: ...CHAPTER 8 CB FAIL PROTECTION ...
Страница 208: ...Chapter 8 CB Fail Protection P54A B C E 182 P54xMED TM EN 1 ...
Страница 219: ...CHAPTER 9 CURRENT PROTECTION FUNCTIONS ...
Страница 220: ...Chapter 9 Current Protection Functions P54A B C E 194 P54xMED TM EN 1 ...
Страница 244: ...Chapter 9 Current Protection Functions P54A B C E 218 P54xMED TM EN 1 ...
Страница 247: ...CHAPTER 10 VOLTAGE PROTECTION FUNCTIONS ...
Страница 248: ...Chapter 10 Voltage Protection Functions P54A B C E 222 P54xMED TM EN 1 ...
Страница 261: ...CHAPTER 11 FREQUENCY PROTECTION FUNCTIONS ...
Страница 262: ...Chapter 11 Frequency Protection Functions P54A B C E 236 P54xMED TM EN 1 ...
Страница 268: ...Chapter 11 Frequency Protection Functions P54A B C E 242 P54xMED TM EN 1 ...
Страница 269: ...CHAPTER 12 MONITORING AND CONTROL ...
Страница 270: ...Chapter 12 Monitoring and Control P54A B C E 244 P54xMED TM EN 1 ...
Страница 300: ...Chapter 12 Monitoring and Control P54A B C E 274 P54xMED TM EN 1 ...
Страница 301: ...CHAPTER 13 SUPERVISION ...
Страница 302: ...Chapter 13 Supervision P54A B C E 276 P54xMED TM EN 1 ...
Страница 312: ...Chapter 13 Supervision P54A B C E 286 P54xMED TM EN 1 ...
Страница 323: ...CHAPTER 14 DIGITAL I O AND PSL CONFIGURATION ...
Страница 324: ...Chapter 14 Digital I O and PSL Configuration P54A B C E 298 P54xMED TM EN 1 ...
Страница 336: ...Chapter 14 Digital I O and PSL Configuration P54A B C E 310 P54xMED TM EN 1 ...
Страница 337: ...CHAPTER 15 FIBRE TELEPROTECTION ...
Страница 338: ...Chapter 15 Fibre Teleprotection P54A B C E 312 P54xMED TM EN 1 ...
Страница 354: ...Chapter 15 Fibre Teleprotection P54A B C E 328 P54xMED TM EN 1 ...
Страница 355: ...CHAPTER 16 ELECTRICAL TELEPROTECTION ...
Страница 356: ...Chapter 16 Electrical Teleprotection P54A B C E 330 P54xMED TM EN 1 ...
Страница 366: ...Chapter 16 Electrical Teleprotection P54A B C E 340 P54xMED TM EN 1 ...
Страница 367: ...CHAPTER 17 COMMUNICATIONS ...
Страница 368: ...Chapter 17 Communications P54A B C E 342 P54xMED TM EN 1 ...
Страница 439: ...CHAPTER 18 CYBER SECURITY ...
Страница 440: ...Chapter 18 Cyber Security P54A B C E 414 P54xMED TM EN 1 ...
Страница 457: ...CHAPTER 19 INSTALLATION ...
Страница 458: ...Chapter 19 Installation P54A B C E 432 P54xMED TM EN 1 ...
Страница 469: ...5 2 CASE DIMENSIONS 60TE E01409 Figure 197 60TE case dimensions P54A B C E Chapter 19 Installation P54xMED TM EN 1 443 ...
Страница 471: ...CHAPTER 20 COMMISSIONING INSTRUCTIONS ...
Страница 472: ...Chapter 20 Commissioning Instructions P54A B C E 446 P54xMED TM EN 1 ...
Страница 513: ...CHAPTER 21 MAINTENANCE AND TROUBLESHOOTING ...
Страница 514: ...Chapter 21 Maintenance and Troubleshooting P54A B C E 488 P54xMED TM EN 1 ...
Страница 530: ...Chapter 21 Maintenance and Troubleshooting P54A B C E 504 P54xMED TM EN 1 ...
Страница 531: ...CHAPTER 22 TECHNICAL SPECIFICATIONS ...
Страница 532: ...Chapter 22 Technical Specifications P54A B C E 506 P54xMED TM EN 1 ...
Страница 558: ...Chapter 22 Technical Specifications P54A B C E 532 P54xMED TM EN 1 ...
Страница 559: ...APPENDIX A ORDERING OPTIONS ...
Страница 560: ...Appendix A Ordering Options P54A B C E P54xMED TM EN 1 ...
Страница 565: ...APPENDIX B SETTINGS AND SIGNALS ...
Страница 566: ...Appendix B Settings and Signals P54A B C E P54xMED TM EN 1 ...
Страница 790: ...Appendix B Settings and Signals P54A B C E B224 P54xMED TM EN 1 ...
Страница 835: ...APPENDIX C WIRING DIAGRAMS ...
Страница 836: ...Appendix C Wiring Diagrams P54A B C E P54xMED TM EN 1 ...
Страница 849: ......