A wavelet-based method to detect, locate, quantify and identify slight deviations of amplitude and phase in power systems

Abstract

Amplitude deviation (AD) and phase deviation (PD) are the important compositions of power quality disturbance (PQD). To analyze PQD deeply, this paper introduces a wavelet-based method for detecting, localizing, separating, quantifying and identifying slight AD and PD. The following are the distinctive features of the method: complex biorthogonal wavelet with the shortest smoothing filter (Haar filter), fast but shift-invariant wavelet transform (WT) at a few scales, automatically separated AD and PD in WT-domain, direct relationship between the WT coefficients and the magnitudes of AD and PD, simple binary feature victor and binary-decimal conversion identifying process. All the novel features make the method simple, correct and fast.