Safe processing method for active voltage reduction of ground fault phase of non-effective grounding system

摘要

A safe processing method for active voltage reduction of a ground fault phase of a non-effective grounding system, for use in safe processing of a ground fault of a neutral point non-effective grounding generator or power distribution network. Windings (As, Bs, Cs) at a non-effective grounding system side of a transformer are separately provided with multiple shunting taps (1, 2, 3, 4, 5); when a single-phase ground fault occurs, a shunting tap of the fault phase winding is selected to be short circuited to ground directly or short circuited to ground by means of impedance (Z), so as to reduce the fault phase voltage, so that the fault point voltage is lower than a ground arc continuous burning voltage to meet a long-term non-stop safe operation requirement. The method can eliminate an instantaneous single-phase ground fault, suppress a permanent single-phase ground fault current, limit a rising amplitude of a non-fault phase voltage, reduce the risk of non-fault phase insulation breakdown, reduce personal safety and equipment security risks, effectively prevent the occurrence of power outages, and improve power supply reliability and security.