Power System Disturbance Recognition Using Wavelet and S-Transform Techniques

Power quality issues have been a source of major concern in recent years due to extensive use of power electronic devices and non-linear loads in electrical power system and consequently sensitive detection and accurate classification of power disturbances have become very much necessary. To monitor electrical power quality disturbances, short time discrete Fourier transform (STFT) is most often used. But for non- stationary signals, the STFT does not track the signal dynamics properly due to the limitations of a fixed window width chosen a priori. This paper presents a new approach for power quality analysis using a modified wavelet transform, known as S-transform and the analysis of several power quality problems using both S-transform as well as discrete wavelet transform validates the superiority of S-transform.