Leakage current patterns on artificially polluted composite insulators

This paper presents results and analyses of different leakage current (LC) waveforms on porcelain, RTV coated and polymeric composite insulators during the clean fog pollution testing under laboratory conditions. The resulting LC waveforms recorded with different time lapses after contamination, are compared both in, time and frequency domains. Flashover voltage measurements are also presented. The waveforms become deformed from sinusoidal shape as voltage level increases. A neural network is trained to recognize the patterns and to evaluate their third harmonic content. The results are compared with fast Fourier transform (FFT) analyses of the patterns