Operation
P74x/EN OP/Na7
MiCOM P741, P742, P743
(OP) 5-
9
OP
FIGURE 4: SENSITIVE EARTH FAULT BLOCKING CHARACTERISTIC
For an external phase fault the SDEF protection will be disabled by the blocking command
as long as the '
I
biasPh>Cur.' threshold remains exceeded.
It can be seen that for an internal phase to phase fault the bias current will be sufficient to
enable the SDEF blocking order. The SDEF protection is then blocked and no trip issued
from this element irrespective of SDEF setting thresholds being exceeded. As the main
phase differential protection is always active, it is able to react to the fault and issue a trip
command accordingly.
For an external phase to phase fault the SDEF will be disabled via the blocking order.
The sensitive differential earth fault protection is delayed by 20ms to prevent any
maloperation during CT saturation condition.
Important note: SDEF should only be used when all the CTs are of the same standard
1.2.4
Threshold coherency.
The measuring elements have several level detectors for differential current. Upon starting,
the protection reacts to any setting inconsistency in the detection of these levels' specific
order.
The differential protection is blocked until the thresholds [I
D
>1and I
D
>2] and [I
D
N>1and
I
D
N>2] are set in the correct sequence.
The thresholds must be set so that:
(
I
D
>1)
(
I
D
>2) , (
I
D
>1)
(
I
DCZ
>2) and (
I
DN
>1)
(
I
DN
>2), (
I
DN
>1)
(
I
DNCZ
>2)
Summary of Contents for P741
Page 2: ......
Page 4: ......
Page 6: ...P74x EN IT Na7 Introduction MiCOM P741 P742 P743 ...
Page 8: ...P74x EN IT Na7 Introduction IT 1 2 MiCOM P741 P742 P743 IT ...
Page 18: ...P74x EN TD Na7 Technical Data MiCOM P741 P742 P743 ...
Page 30: ...P74x EN TD Na7 Technical Data TD 2 14 MiCOM P741 P742 P743 TD ...
Page 32: ...P74x EN GS Na7 Getting Started MiCOM P741 P742 P743 ...
Page 70: ...P74x EN ST Na7 Getting Started MiCOM P741 P742 P743 ...
Page 72: ...P74x EN ST Na7 Settings ST 4 2 MiCOM P741 P742 P743 ST ...
Page 116: ...P74x EN OP Na7 Operation MiCOM P741 P742 P743 ...
Page 120: ...P74x EN OP Na7 Operation OP 5 4 MiCOM P741 P742 P743 OP ...
Page 136: ...P74x EN OP Na7 Operation OP 5 20 MiCOM P741 P742 P743 OP FIGURE 8 CB FAIL LOGIC ...
Page 166: ...P74x EN AP Na7 Application Notes MiCOM P741 P742 P743 ...
Page 234: ...P74x EN PL Na7 Programmable Logic MiCOM P741 P742 P743 ...
Page 290: ...P74x EN PL Na7 Programmable Logic PL 7 56 MiCOM P741 P742 P743 PL ...
Page 291: ...Programmable Logic P74x EN PL Na7 MiCOM P741 P742 P743 PL 7 57 PL ...
Page 292: ...P74x EN PL Na7 Programmable Logic PL 7 58 MiCOM P741 P742 P743 PL ...
Page 294: ...P74x EN PL Na7 Programmable Logic PL 7 60 MiCOM P741 P742 P743 PL ...
Page 295: ...Programmable Logic P74x EN PL Na7 MiCOM P741 P742 P743 PL 7 61 PL ...
Page 296: ...P74x EN PL Na7 Programmable Logic PL 7 62 MiCOM P741 P742 P743 PL ...
Page 298: ...P74x EN PL Na7 Programmable Logic PL 7 64 MiCOM P741 P742 P743 PL ...
Page 299: ...Programmable Logic P74x EN PL Na7 MiCOM P741 P742 P743 PL 7 65 PL ...
Page 300: ...P74x EN PL Na7 Programmable Logic PL 7 66 MiCOM P741 P742 P743 PL ...
Page 302: ...P74x EN MR Na7 Measurements and Recording MiCOM P741 P742 P743 ...
Page 324: ...P74x EN FD Na7 Firmware Design MiCOM P741 P742 P743 ...
Page 344: ...P74x EN FD Na7 Firmware Design FD 9 20 MiCOM P741 P742 P743 FD FIGURE 10 P74x SYSTEM OVERVIEW ...
Page 351: ...Firmware Design P74x EN FD Na7 MiCOM P741 P742 P743 FD 9 27 FD ...
Page 353: ...P74x EN CM Na7 Commissioning MiCOM P741 P742 P743 ...
Page 429: ...P74x EN MT Na7 Maintenance MiCOM P741 P742 P743 ...
Page 431: ...P74x EN MT Ma7 Maintenance MT 11 2 MiCOM P741 P742 P743 MT ...
Page 451: ...P74x EN TS Na7 Troubleshooting MiCOM P741 P742 P743 ...
Page 453: ...P74x EN TS Na7 Troubleshooting TS 12 2 MiCOM P741 P742 P743 TS ...
Page 475: ...P74x EN SC Na7 SCADA Communications MiCOM P741 P742 P743 ...
Page 499: ...P74x EN SC Na7 SCADA Communications SC 13 24 MiCOM P741 P742 P743 SC ...
Page 501: ...P74x EN SG Na7 Symbols and Glossary MiCOM P741 P742 P743 ...
Page 511: ...P74x EN SG Na7 Symbols and Glossary SG 14 10 MiCOM P741 P742 P743 SG Logic Gates ...
Page 513: ...P74x EN IN Na7 Installation MiCOM P741 P742 P743 ...
Page 515: ...P74x EN IN Na7 Installation IN 15 2 MiCOM P741 P742 P743 IN ...
Page 528: ...Installation P74x EN IN Na7 MiCOM P741 P742 P743 IN 15 15 IN FIGURE 6 P742 40TE REAR VIEW ...
Page 533: ...P74x EN VH Na7 Firmware and Service Manual Version History MiCOM P741 P742 P743 ...
Page 542: ...APPENDIX A WIRING DIAGRAMS ...
Page 543: ...Appendix A Wiring Diagrams P74x P74x EN M Na7 ...
Page 559: ......