PurposeThe purpose of this paper is to compare the accuracy of tracking the amplitude and frequency changes of non‐stationary electric signals.Design/methodology/approachShort‐time fourier transform (STFT) and S‐transform algorithms were applied to analyze non‐stationary signals originating from switching of capacitor banks in a power system.FindingsThe S‐transform showed possibilities of sharp localization of the basic component, and allowed improvement of tracking dynamism the transient components in comparison to STFT.Practical implicationsS‐transform is a better tool for the analysis of non‐stationary waveforms in power systems and its properties can be used for diagnostic and power quality applications.Originality/valueThe dynamic tracking of the changes in time and frequency of real‐like signals originating from a power system are investigated in this paper.