Non-stationary signals' analysis in power systems. A time-frequency approach

In this paper, a brief presentation of the state of the art in Fourier-like domains applied to power quality analysis is made, together with the main results obtained until now with a wavelet approach. Definitions of Walsh immittance, of network' topology in other than sinusoidal spaces and relations between Fourier, windowed-Fourier, Walsh, Gabor and wavelet transforms are presented. The paper is intended to be a guide to power systems engineers that could be overwhelmed by notions coming from such a rapidly developing new area (wavelets) or from the already "mythical" Fourier analysis.