Leonowicz, ZTime-Frequency Analysis of Distorted Electric Signals using a Complex Space-PhasorWe consider applying non-parametric and parametric methods for calculation of time-frequency representation of non-stationary electric waveforms. Space phasor is applied as a complex representation of 3-phase signals and visualization of the spectrum of positive and negative-sequence components. We compare the uncertainty of measurements using described time-frequency representations, as well as a widely used Fourier techniques. Proposed methods allow tracking instantaneous frequency as well as magnitude of non-stationary signals in power systems. Possible applications in diagnosis and power quality area are targeted.EEEIC20082008-01-04