Analysis of harmonics using S-Transform

摘要

This paper introduces the method for evaluating the harmonic contents of power system waveform. The disturbed signal is split into many frequency sub-bands in Frequency domain, where the disturbing time and level can be identified. The aliasing problem which presents in Discrete Wavelet Transform (DWT) can be restored using Lifting Wavelet Transform which ensures perfect reconstruction property of the signal and the lack of time invariance property in LWT can be restored by up sampling the filter coefficients in stationary wavelet transform. The S-Transform (ST), is evolved from the ideas of wavelet transform, and is based on a moving and scalable localizing Gaussian window whose characteristics are superior to earlier types of the transforms. A comparative analysis will be done with results obtained from the S-Transform and conventional methods for different measuring conditions and Simulation results are given.