Feeder Selection Method of Single-Phase High Impedance Grounding Fault in SRGS

When a single-phase high impedance grounding fault (HIGF) occurs in power grid with small resistance grounding system (SRGS), the overcurrent protection does not work, which may expand the fault range and evolve into a more serious fault. In this paper, a HIGF feeder selection method is proposed to solve this problem. Firstly, the zerosequence equivalent model of single-phase grounding fault in SRGS is established, and the features of single-phase low resistance grounding fault and that of single-phase HIGF are compared. Then, the characteristics of feeder zero sequence current (ZSC) is analyzed, and the correlation between neutral resistance current (NRC) and feeder ZSC is discussed. Finally, the correlation coefficient between NRC and each feeder ZSC is calculated, and the faulty feeder is selected according to the difference of correlation coefficient. Simulation results show that the proposed method is effective and robust to noise.