GE P742

P74
x/EN AP/Na7
Application Notes
(AP) 6
-2 MiCOM P74
1, P742, P743
AP
6.5 Topology processing 33
6.5.1 Single bar or double bus with bus sectionaliser 33
6.5.2 Double bus with one CT bus coupler 34
6.5.3 Double bus with two CT bus coupler 35
6.5.4 CTs on one side of bus coupler, CB closes before status acquisition. 38
6.5.5 CTs on both sides of bus coupler, CB closes before status acquisition. 39
6.5.6 CTs on one side of bus coupler, CB closed and fault evolves between CT and CB
(even for switch onto fault). 39
6.5.7 CTs on both sides of coupler, CB closed and fault evolves between CT and CB. 42
7. UNDERTAKING A NUMERICAL DIFFERENTIAL BUSBAR
PROTECTION PROJECT 44
7.1 Check list 44
7.2 General Substation information 45
7.3 Short Circuit Levels 45
7.4 Switchgear 46
7.5 Cubicle specifications 46
7.6 Substation Architecture 47
8. STANDARD CONFIGURATIONS 48
9. APPLICATION OF NON PROTECTION FUNCTIONS 60
9.1 Function keys 60
9.2 Differential current display 61
10. CT REQUIREMENTS 62
10.1 Notation 62
10.2 87BB Phase CT Requirements 62
10.2.1 Feeders connected to sources of significant power (i.e. lines and generators) 62
10.2.2 Out of service feeders or those with low power contribution (low infeed) 62
10.2.3 CT Specification according to IEC 185, 44-6 and BS 3938 (British Standard) 63
10.3 87BB Sensitive Differential Earth Fault CT Requirements 64
10.4 Support of IEEE C Class CTs 64
11. AUXILIARY SUPPLY FUSE RATING 66