Abstract：In order to solve the problem of the difficulty of the fault line selection for single phase to ground fault, a small current grounding fault line selection strategy based on wavelet theory and fault transient signal is proposed.Firstly, the method determines whether the grid occur a ground fault according to that whether the grid zero-sequence voltage occurssa sudden sharp rise, and the time point of a ground fault based on the time of modulus maxima of the zero-sequence voltage occurs.Secondly, the line current data before and after the failure within a cycle is extracted to conduct wavelet decomposition.Finally, the fault line is determined through analyzing and comparing the results of current wavelet decomposition.The effectiveness of the method has been validated in multiple field instances, which is an effective method for fault line selection.

Keyword：petersen coil;small current grounding;fault line selection;wavelet decomposition;