Probabilistic assessment of insulator failure under contaminated conditions

This study presents a probabilistic approach, based on the finite element method (FEM), to model insulator flashover and calculate the failure risk of insulators under contaminated conditions. In the proposed method, the voltage distribution along the insulator surface is estimated by FEM and the random turn wheel is utilised to describe the stochastic propagation of arc along the insulator surface as well as in the air. This basis is used to obtain the probability of insulator flashover for different contaminations, separately. Then, from the simulation results, the probability density function of flashover in terms of pollution can be determined based on the Kolmogorov–Smirnov test. The proposed model is verified by comparing the associated results with those of the literature, in which the reliability and accuracy of the presented method are approved. Finally, having the cumulative distribution function of insulation strength and probability density function of pollution stress, the failure risk is calculated, in which the results can be used to predict the annual outage rate of transmission lines.