Detector of Power Quality Disturbance Signal with Random Phase Offset

Abstract

The wavelet- or wavelet packet-based power quality disturbance (PQD) signal detection is highly sensitive to random phase offset owing to their shift-variant characteristics, which has not yet been well discussed in the literature. In this letter, we newly define the wavelet packet transform modulus (WPTM), introduce the two WPTM metrics (MV and RMS) with an optimum factor k modifying conventionally defined universal threshold, and present a WPTM-based PQD detector using those metrics that is robust against severe channel conditions with random phase offset. Simulation results verify that the presented method greatly reduces false edge detection rate (FER) (< 10%), while maintaining a high detection rate (DR), when compared to existing wavelet- or wavelet packet-based methods.