Wavelet as a diagnostic tool for fault classification and identification in underground power cable

In this paper, a diagnostic technique based on the wavelet transform (WT) for identifying and classifying different fault types is developed. In general, the wavelet transform provides multiresolution type analysis with variable window size; thus better suited for such analysis. Variable window sizes provide good resolution in the time and frequency domains; thus helping not only in identifying the fault, but also in localizing it. Three types of cables are used in this study; a normal cable, a shorted cable, and a cable with holes. Wavelet transformation is then applied to the impedance in each case, with various windowing to eliminate possible interference. The identification is then carried out by examining the resulting impedance magnitude. This study reveals that the wavelet transform is a better tool for fault identification and classification.