Partial discharge detection as a tool to infer pollution severity of polymeric insulators

This paper deals with the analysis of partial discharge characteristics of silicone rubber insulators, with the aim to develop a better diagnostic tool to identify the pollution severity of outdoor insulators. In this work, laboratory-based pollution performance tests are carried out on silicone rubber insulators under ac voltage at different pollution levels and relative humidity conditions, using sodium chloride as a contaminant. Partial discharge (PD) is acquired through an innovative PD detection system which is able to collect PD waveforms beside PD patterns. Time domain and frequency domain characteristics of PD pulses at different surface pollution conditions are studied. Statistical parameters of PD patterns are also evaluated in order to achieve a quantitative assessment of pollution severity of polymeric insulators. The results on silicone rubber insulators show that the pollution severity of outdoor polymeric insulators could be identified from the partial discharge pattern analysis.