Practical application of wavelet to power quality analysis

Abstract

This paper presents a computational algorithm for identifying power frequency variations, sub-harmonics, integer harmonics and inter-harmonics, by using wavelet-based transform. The continuous wavelet transform (CWT) using the complex morlet wavelet is adopted to detect the harmonic frequencies presented in a power signal. The frequency detection algorithm is developed from the wavelet ridges and scalogram. A necessary condition is established to discriminate adjacent frequencies. The instantaneous frequency identification approach is applied for the determination of frequencies components presented in a power signal. An algorithm based on the discrete stationary wavelet transform (SWT) is developed to determine the amplitudes of the harmonic frequencies presented in the power signal from the coefficients computed by the CWT.