Distance protection using a novel phasor estimation algorithm based on wavelet transform

This paper presents a novel phasor estimation algorithm, which combines the filtering characteristics of the maximal overlap discrete wavelet transform (MODWT) and the least error square (LES) algorithm. Time and frequency response of the designed filters are compared to the ones of traditional discrete Fourier transform (DFT) filters. The obtained results indicate that the designed filters have time responses compatible half cycle DFT-based filters, with the advantage that their frequency responses are close to the ones of full cycle DFT-based filters. According to these characteristics, the designed filters may be used in secure high-speed distance protection.