Application of the continuous wavelet transform to intermittent high impedance ground fault detection in MV networks

Application of the wavelet transform (WT) to design of a single phase-to-ground protection algorithm that could be applied to medium voltage (MV) relay design in overhead and cable transmission lines is presented. The algorithm concept is based on the phase comparison between wavelet coefficients of zero sequence voltage and current signals. The idea was tested for signals generated in the physical model of the MV network. The results obtained are presented and the advantages as well as the limitations of the algorithm presented are discussed.