8-6 F60 Feeder Protection System GE Multilin8.2 FAULT LOCATOR 8 THEORY OF OPERATION8For BG faults:(EQ 8.8)For CG faults:(EQ 8.9)For AB and ABG faults:(EQ 8.10)For BC and BCG faults:(EQ 8.11)For CA and CAG faults:(EQ 8.12)where K0 is the zero sequence compensation factor (for the first six equations above)For ABC faults, all three AB, BC, and CA loops are analyzed and the final result is selected based upon consistency of theresultsThe element calculates the distance to the fault (with m in miles or kilometers) and the phases involved in the fault.The relay allows locating faults from delta-connected VTs. If the FAULT REPORT 1 VT SUBSTITUTION setting is set to “None”,and the VTs are connected in wye, the fault location is performed based on the actual phase to ground voltages. If the VTsare connected in delta, fault location is suspended.If the FAULT REPORT 1 VT SUBSTITUTION setting value is “V0” and the VTs are connected in a wye configuration, the faultlocation is performed based on the actual phase to ground voltages. If the VTs are connected in a delta configuration, faultlocation is performed based on the delta voltages and externally supplied neutral voltage:(EQ 8.13)If the FAULT REPORT 1 VT SUBSTITUTION setting value is “I0” and the VTs are connected in a wye configuration, the fault loca-tion is performed based on the actual phase to ground voltages. If the VTs are connected in a delta configuration, fault loca-tion is performed based on the delta voltages and zero-sequence voltage approximated based on the zero-sequencecurrent:(EQ 8.14)where Z SYS0 is the equivalent zero-sequence impedance behind the relay as entered under the fault report setting menu.V A V AB= , I A I AB K0 I0A, I AF I AB I ApreB–=⋅+=V A V AC= , I A I AC K0 I0A, I AF I AC I ApreC–=⋅+=V A V AA V AB–= , I A I AA I AB–=V A V AB V AC–= , I A I AB I AC–=V A V AC V AA–= , I A I AC I AA–=V A13--- V N V AB V CA–+( )=V B13--- V N V BC V AB–+( )=V B13--- V N V CA V BC–+( )=V A13--- V AB V CA–( ) Z SYS0I0–=V B13--- V BC V AB–( ) Z SYS0I0–=V B13--- V CA V BC–( ) Z SYS0I0–=
