P74x/EN OP/Na7
Operation
(OP) 5-
16
MiCOM P741, P742, P743
OP
1.3.3
Circuit Breaker Fail (CBF)
The detailed logic of the circuit breaker failure element follows.
1.3.3.1 Distributed Tripping, Control and Indication Elements (Peripheral Units)
As the P74x scheme has been designed for use as either a centralised or distributed
scheme, the hardware corresponds to one circuit breaker and can accommodate 1 or 2 trip
coils:
•
1 main trip coil
•
1 back-up trip coil
Furthermore these can be either 3 single-phase trip coils or 1 three-phase trip coil. These
can be combined for example 3 single-phase trip coils on the main system and 1 three-
phase trip coil for the back-up system.
Note:
- The backtrip order (coming from the Central Unit) is always given to
the relay 1, 2 and 3 even if the CBF is disabled in the Peripheral
Units.
- The retrip has to be done using the PSL.
1.3.3.2 Circuit Breaker Fail Reset Criteria
1.3.3.2.1 Overcurrent Criterion
One of the most common causes of busbar mal-tripping is error introduced in the back
tripping of adjacent sections. To prevent such an error it is possible to condition the
operation of 50BF protection only when there is presence of a significant current i.e. a short-
circuit on the concerned feeder. This confirmation is provided by the
I
> threshold which is set
by default at 1.2 times the nominal rated current of the CT and/or by the threshold setting of
residual current
I
N
> set by default to 0.2 times the rated current.
1.3.3.2.2 Undercurrent reset Criterion
The criterion normally used for the detection of a circuit breaker pole opening is the
disappearance of the current i.e. undercurrent element. This function is generally preferred
above other elements due to its very fast response time. In P74x this method of detection is
utilised and has the threshold
I
<.
See figure 8, part
for phase A.
Note:
The same algorithm is used for the other phases.
This Undercurrent elements have an I< threshold, which is used to supervise that each
circuit breaker has opened correctly, when commanded to do so. By use of the I< threshold,
it is possible to ensure that all load and fault current has been ruptured, ensuring that no
arcing remains across the circuit breaker primary contacts. Optionally, the user can decide to
include 52a supervision in the breaker fail logic (see chapters 1.3.3.2.3 and 1.3.3.2.4).
The first function is to compare the current sample to the I< threshold and check for the
following sequence:
•
positive value of the current
•
no current (below the threshold)
•
negative value of the current
•
no current (below the threshold)
•
positive value of the current
•
…
Содержание P741
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Страница 6: ...P74x EN IT Na7 Introduction MiCOM P741 P742 P743 ...
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Страница 18: ...P74x EN TD Na7 Technical Data MiCOM P741 P742 P743 ...
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Страница 32: ...P74x EN GS Na7 Getting Started MiCOM P741 P742 P743 ...
Страница 69: ...Settings P74x EN ST Na7 MiCOM P741 P742 P743 ST SETTINGS Hardware Suffix J and K Software Version 51 ...
Страница 70: ...P74x EN ST Na7 Getting Started MiCOM P741 P742 P743 ...
Страница 72: ...P74x EN ST Na7 Settings ST 4 2 MiCOM P741 P742 P743 ST ...
Страница 115: ...Operation P74x EN OP Na7 MiCOM P741 P742 P743 OP OPERATION Hardware Suffix J and K Software Version 51 ...
Страница 116: ...P74x EN OP Na7 Operation MiCOM P741 P742 P743 ...
Страница 120: ...P74x EN OP Na7 Operation OP 5 4 MiCOM P741 P742 P743 OP ...
Страница 136: ...P74x EN OP Na7 Operation OP 5 20 MiCOM P741 P742 P743 OP FIGURE 8 CB FAIL LOGIC ...
Страница 165: ...Application Notes P74x EN AP Na7 MiCOM P741 P742 P743 AP APPLICATION NOTES Hardware Suffix J and K Software Version 51 ...
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Страница 289: ...Programmable Logic P74x EN PL Na7 MiCOM P741 P742 P743 PL 7 55 PL P741 PROGRAMMABLE SCHEME LOGIC ...
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Страница 297: ...Programmable Logic P74x EN PL Na7 MiCOM P741 P742 P743 PL 7 63 PL P743 PROGRAMMABLE SCHEME LOGIC ...
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Страница 299: ...Programmable Logic P74x EN PL Na7 MiCOM P741 P742 P743 PL 7 65 PL ...
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Страница 302: ...P74x EN MR Na7 Measurements and Recording MiCOM P741 P742 P743 ...
Страница 323: ...Firmware Design P74x EN FD Na7 MiCOM P741 P742 P743 FD FIRMWARE DESIGN Hardware Suffix J and K Software Version 51 ...
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Страница 351: ...Firmware Design P74x EN FD Na7 MiCOM P741 P742 P743 FD 9 27 FD ...
Страница 352: ...Commissioning P74x EN CM Na7 MiCOM P741 P742 P743 CM COMMISSIONING Hardware Suffix J and K Software Version 51 ...
Страница 353: ...P74x EN CM Na7 Commissioning MiCOM P741 P742 P743 ...
Страница 428: ...Maintenance P74x EN MT Na7 MiCOM P741 P742 P743 MT MAINTENANCE Hardware Suffix J and K Software Version 51 ...
Страница 429: ...P74x EN MT Na7 Maintenance MiCOM P741 P742 P743 ...
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Страница 450: ...Troubleshooting P74x EN TS Na7 MiCOM P741 P742 P743 TS TROUBLESHOOTING Hardware Suffix J and K Software Version 51 ...
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Страница 475: ...P74x EN SC Na7 SCADA Communications MiCOM P741 P742 P743 ...
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Страница 501: ...P74x EN SG Na7 Symbols and Glossary MiCOM P741 P742 P743 ...
Страница 511: ...P74x EN SG Na7 Symbols and Glossary SG 14 10 MiCOM P741 P742 P743 SG Logic Gates ...
Страница 512: ...Installation P74x EN IN Na7 MiCOM P741 P742 P743 IN INSTALLATION Hardware Suffix J and K Software Version 51 ...
Страница 513: ...P74x EN IN Na7 Installation MiCOM P741 P742 P743 ...
Страница 515: ...P74x EN IN Na7 Installation IN 15 2 MiCOM P741 P742 P743 IN ...
Страница 528: ...Installation P74x EN IN Na7 MiCOM P741 P742 P743 IN 15 15 IN FIGURE 6 P742 40TE REAR VIEW ...
Страница 533: ...P74x EN VH Na7 Firmware and Service Manual Version History MiCOM P741 P742 P743 ...
Страница 542: ...APPENDIX A WIRING DIAGRAMS ...
Страница 543: ...Appendix A Wiring Diagrams P74x P74x EN M Na7 ...
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