Detection, classification and localization of power system impulsive transients using S-transform

Power quality issues have been of a great concern in recent years due to extensive use of power electronic devices and non-linear loads in electrical power system. In order to monitor electrical power quality disturbance, short time discrete Fourier transform (STFT) is most often used. But in case of non-stationary signals, STFT does not track the signal dynamics properly due to limitations of a fixed window width chosen a priori. By using wavelet transform, disturbances in electrical power system can only be detected and localized, but for sake of classification, standard multi-resolution analysis or other classification techniques must be used. This paper presents a new approach for power quality analysis along with classification using a modified wavelet transform, known as S-transform. Case studies for detection and classification several complex power quality disturbances for impulsive transients using S-transform have been corroborated in this paper and the results contained in this paper validate superiority of S-transform over wavelet transform.