Welch periodogram analysis of the leakage current on insulator model under wetted contaminated conditions for flashover prediction

This work is devoted to study the dielectric performances of a plane model wetted and contaminated by salt solutions having different conductivities. This insulator model simulates the 1512 L outdoor insulator which is greatly used by the Algerian Company of Gas and Electric Power (SONELGAZ). In this paper, we present signal processing results obtained through leakage current waveforms in order to predict the insulator flashover. These investigations were achieved after calculations operated on the leakage current energy by using the Welch frequency spectrum analysis. This frequency representation is performed on leakage current waveforms during the electric discharges activity appearing on the polluted plane surface. Reported results showed that the occurrence of electric discharges induced a progressive evaporation of the electrolytic solution and that this evaporation became stronger with the increase of pollution level.