Application of Wavelet Transform for Monitoring Short Duration Disturbances in Distribution Systems

This paper presents features that characterize power quality disturbances from recorded voltage waveforms using wavelet transform. The concept of Discrete Wavelet Transform for feature extraction of power quality disturbance signals has been incorporated as a powerful tool for detecting and classifying power quality disturbances like Sag, Swell and Interruption and decomposed up to 4 levels using Db4 wavelet. The Multiresolution analysis is used to classify and quantify the power quality disturbances which obtained by plotting the standard deviations of the decomposed signal at different resolution level. The clear information for detection of power quality disturbances are obtained by plotting the entropy of the decomposed signal at different levels.