Analysis of the pollution accumulation and flashover characteristics of field aged 110kV composite insulators

This paper takes the composite insulator being operated in a certain 110kV power network in China as the sample, tests and analyzes the pollution depositing rules and flashover performance of it. Test results indicate that the equivalent salt deposit density (ESDD) and non-soluble deposit density (NSDD) on the upper and lower surface of composite insulators energized running voltage is different. The ratio of the ESDD and NSDD of upper surface to that of lower surface is 0.76 and 0.46 separately. The structure and shape of polymeric insulators have influence on the pollution deposit levels and non-uniform degree. The dispersion of the pollution flashover voltage of naturally polluted composite insulators is great. Under the same condition, the pollution flashover voltage of naturally polluted composite insulators is higher about 50% than that of artificially polluted composite insulators. The difference of hydrophobicity, component of contamination and non-uniform degree of pollution are the main reason that caused the pollution flashover voltage of naturally polluted composite insulators is higher than that of artificially polluted composite insulators.