Power quality analysis using linear time-frequency distribution

This paper presents the implementation of linear time-frequency distribution (TFD) techniques to analyze power quality signals. The power quality signals are swell, sag, interruption, transient, harmonic, interharmonic, notching and normal voltage based on IEEE Std. 1159-1995. The time-frequency analysis techniques selected are spectrogram and Gabor transform. From the time-frequency representation (TFR) obtained, the signal parameters are estimated to identify the signal characteristics. Identified signal characteristics that are used as input to a classifier includes the average of root mean square (RMS) voltage, total waveform distortion, total harmonic distortion and total nonharmonic distortion and duration of swell, sag, interruption and transient. From the linear time-frequency analysis techniques used, the optimal technique is chosen in terms of accuracy, computation complexity and memory size.