A study on probabilistic assessment of contamination flashover of high voltage insulator

Insulation design against insulator contamination has been made so far by using the traditional deterministic method. In this method, the maximum contamination severity is first assumed. Then, a certain margin is counted between the withstand voltage obtained from actual tests and the target operating voltage. However, both contamination severity and the withstand voltage are probabilistic variables. In the present paper, as a first step in this probabilistic approach, a risk-of-failure study of 800 kV transmission line insulation was made by treating contamination severity and degree of wetting as probabilistic variables.>