FEEDER POWER SOURCE PROVIDING OPEN FEEDER DETECTION FOR A NETWORK PROTECTOR BY SHIFTED NEUTRAL

摘要

A feeder power source (1) for a network power system (10) includes a network transformer (12) having a delta three-phase primary winding (18) and a three-phase secondary winding (72); a three-phase primary feeder (6) electrically connected to the delta three-phase primary winding; a three-phase secondary bus (77) electrically connected to the three-phase secondary winding; and a three-phase electrical switching apparatus (4) structured to open and close the three-phase primary feeder. A network protector (62) includes a network relay (64) and a three-phase circuit breaker (76) structured to open and close the three-phase secondary bus. A first circuit (2;20;34) is electrically connected between at least one phase of the three-phase primary feeder and ground, and is structured to unbalance shunt impedance to the three-phase primary feeder ground. A second circuit (40) detects a shift in system neutral (N) and detects that the three-phase primary feeder is opened by the three-phase electrical switching apparatus.