The Study of Generalized S-Transform in Power Quality Disturbances Analysis

A new method based on generalized S-transform (GST) is presented for detecting and identifying power quality disturbances (PQDs). The GST formula of discrete time series is deduced firstly, and then nine kinds of typical PQDs are formed for GST analysis. As a result of GST analysis, three voltage-based characteristics, one frequency-based characteristic as well as one phase-based characteristic are extracted. According to the comparison of identification validity between GST and S-transform( ST) made in this paper, GST shows its advantage that it can detect not only voltage instantaneous varies, but also PQDs phase variation. Furthermore, the approach is proved to be quite viable for inter-harmonics detection.