The application of wavelet analysis in identifying transformer magnetizing inrush current

Based on wavelet analysis, the power transformer magnetizing inrush current can be identified. Wavelet analysis can detect the characteristics of the abrupt change signal and B spline wavelet can analyze sample data generated by simulating. The Lipschitz index which means the abrupt level of the signal can be got through analyzing and comparing local maxima of the corresponding signal wavelet coefficients. The magnetizing inrush current can be separated from the fault current by Lipschitz index. The analysis shows that the Lipschitz index of fault current is higher than that of inrush current, thus it is advisable to determine the threshold of a Lipschitz exponent to identify inrush current. The results of simulation verify validity and feasibility of the proposed method.