Application of modified Wigner distribution method to voltage flicker-generated signal studies

With the time–frequency localization characteristics embedded in Wigner distribution, the time and frequency information of a waveform can be both integrally presented. Yet, due to the cross-term problem, the inspection performance is often affected. Therefore, in this study, with the assistance of a window function design, we have proposed a modified Wigner distribution method and applied to voltage flicker-generated signal analysis. This approach not only effectively reserves the merits of Wigner distribution and short-time Fourier transform, but also highly decreases the probability of cross-term occurrence. In order to confirm the feasibility of the method, it has been tested to inspect several voltage flicker-generated signals collected from both simulated waveforms and field measurements. Test results support the feasibility of the method for the application investigated.

► The approach increases the frequency resolution and solves the cross-terms problem.
► The method reserves the merits of Wigner distribution and short-time Fourier transform.
► It is able to realize the time–frequency visualization of flicker signals.
► It can be embedded to analyze other industry interferences and electric power disturbances.