The most suitable mother wavelet for steady-state power system distorted waveforms

The proliferation of nonlinear load in the electric power system leads to steady-state waveform harmonic distortion. Since harmonic distortion has harmful effects on the electric power system, there is a need to analyze and hence accurately measure their values which is an issue of great concern especially in a deregulated environment. Conventional Fourier based analyzing tools have some limitations concerning frequency and time resolutions. Although wavelet transform overcomes these limitations, it suffers from the problem of spectral leakage which is related to the choice of the wavelet family and the mother wavelet used in the analysis. In order to minimize these errors, this paper presents an approach to select the most suitable wavelet family and the most suitable mother wavelet to achieve accurate measurement of steady-state harmonic distortion using the discrete wavelet transform (DWT). The proposed algorithm is simple and proves to be accurate when applied to two cases of different distortion level.