The use of wavelets for the monitoring and diagnostic of surface state of HV polluted insulators

In order to ensure the continuity and the quality of electrical energy distribution, the diagnostic of polluted insulators is of utmost importance. For this purpose, a new performance monitoring methodology is proposed in this paper. Once acquisition of the applied voltage and the leakage current signals is carried out on a plan insulator model under uniform and non-uniform pollutions, the continuous (CWT) and discrete (DWT) wavelet transforms are performed. In case of a uniform pollution, the CWT with its time-scale analysis allows to characterize the state of the insulator surface by detecting the apparition of electrical discharges from the applied voltage waveform. While for a non-uniform pollution configuration, the DWT through its multi-resolution analysis allows us to predict the occurrence of the partial arcs phenomenon on the insulator surface based on the leakage current waveform. Through this work, the effectiveness of the wavelet technique has been highlighted as a new tool for the diagnostic and monitoring of polluted insulators performance.