Identification of power quality disturbances using the MATLAB wavelet transform toolbox

This paper presents an approach that is able to provide the detection and location in time as well as the identification of power quality problems present in both transient and steady-stable signals. The method was developed by using the discrete wavelet transform (DWT) analysis. The given signal is decomposed through wavelet transform and any change on the smoothness of the signal is detected at the finer wavelet transform resolution levels. Later, the energy curve of the given signal is evaluated and a relationship between this energy curve and the one of the corresponding fundamental component is established. The paper shows that each power quality disturbance has unique deviations from the pure sinusoidal waveform and this is adopted to provide a reliable classification of the type of disturbance.