High impedance fault line selection method for resonant grounding system based on wavelet packet analysis

Abstract

Distribution network resonant grounding system of high resistance grounding fault handling has been a research focus, due to the uncertainty of the weak fault current, fault occurrence time, affected by the circuit parameters and random factors such as reason, has been a lack of reliable high resistance grounding fault line selection method. According to the fault characteristics of single phase high impedance grounding of resonant grounding system, wavelet packet analysis and energy entropy are combined to analyze the transient zero sequence current, set the energy entropy be the transient characteristic of single phase high resistance ground fault, so we can analyze the uncertainty of transient fault quantitatively. Analyzing the law of energy entropy distribution of zero sequence current transient signal, and defining the mean energy entropy is to calculate the complexity of signal energy, then proposing a fault model classification method based on average energy entropy. Single-phase high resistance earth fault can be divided into 2 fault types, and according to the different fault types, using different algorithms for fault line selection, finally use simulation data to prove the correctness and feasibility of the method.