High-impedance fault detection utilizing a Morlet wavelet transform approach

An application of Morlct wavelets to the analysis of high-impedance fault generated signals is proposed in this paper. With the time-frequency localization characteristics embedded in wavelets, the time and frequency infoolmation of a waveform can be presented as a visualized schemc. Different from the fast Fourier transform, the wavelet transfoim approach is more cfficient in monitoring fault signals as timc varies. The proposed method has becn applied to discriminate the high-impedance faults from the normal switching events, and to examine the faults undcr various grounds including Portland cement, wet soil and grass. Tcsting rcsults have demonstrated the practicality and advantages of the proposcd method for thc applications.