Fault disappearing judgement of single phase grounding in neutral point non-effective grounding system based on adjustable resistor

摘要

In the distribution network, it is important to determine whether single phase grounding fault has disappeared in time. The reason is that accurate determination contribute to improving safety of system operation and reliability of power supply. This paper proposed a method to judge the disappearance of single phase ground fault based on neutral point non-effective grounding system by means of adjustable resistor. When single phase grounding occurs, forcibly grounding the fault phase at the busbar could reduce fault point voltage and reduce high residual voltage hazard. Then adjust the value of adjustable resistor at the busbar grounding branch, and then monitor the trend of grounding branch current to determine if the fault has disappeared. Simulation results show that the proposed method can accurately and timely judge whether single phase grounding fault disappears.