Abstract:In order to avoid a failure in the single-phase automatic reclosing device’s permanent fault, in view of the high voltage transmission lines, single-phase grounding fault based on instantaneous fault and permanent fault phase voltage characteristic analysis reveals that from the principle of the secondary arc combustion phase it is obviously different from two kinds of fault voltage of the signal energy distribution. Based on this, the single-phase fault using wavelet packet energy spectrum is put forward to identify the nature of the method. Theoretical analysis and a large quantity of electromagnetic transient program EMTP - RV results show that the method can more accurately simulate the actual fault, and has good practical application value.