Comparison between Wavelet Packet Transform and M-band Wavelet Packet Transform for Identification of Power Quality Disturbances

Due to large incorporation of nonlinear loads in the present day distribution system, the voltage and currents are significantly distorted. This distortion of an electrical signal results in large economic loss and loss of data. Therefore all over the world more and more attention is paid to Power Quality (PQ) problems identification and its solutions. It is very much essential to correctly identify PQ disturbance to derive the appropriate compensation strategies.This paper focuses on the identification of the PQ disturbances such as voltage sag, voltage swell, and voltage sag with harmonics, voltage swell with harmonics, momentary interruption, flicker, transients and harmonics using M-band Wavelet Packet Transform (M-band WPT). These PQ problems are simulated in MATLAB environment as per their IEEE 1159-2009 standard definition. Detection of PQ disturbances is carried out using a statistical parameter RMS_wpt computed for each decomposition coefficient of conventional WPT and M-band WPT. Finally the results obtained using both the mathematical tools are compared and concluded.