A Probabilistic Method to Assess the Risk of Contamination-Induced Insulator Flashover

When wetted by heavy fog, light rain, or condensation, the contamination that accumulates over time on the surface of an insulator can form a conductive pathway that may result in flashover, consequences of which include insulator damage and unexpected power outages. Rain or manual washing can remove built-up contamination from an insulator’s surface, reducing the risk of contamination-induced flashover. However, regularly washing all insulators may be infeasible for electric power companies with large service territories. To inform long-term risk mitigation efforts, we propose a probabilistic method to assess the rate of contamination-induced insulator flashover using site-specific air quality model (AQM) and rainfall data. The model accounts for uncertainty in the amount of accumulated deposition on the surface of an insulator and in the flashover voltage of the contaminated insulator. We demonstrate one possible implementation of the method for two hypothetical insulators—one ceramic and one polymer—at an example site. The proposed method can also be adapted for short-term asset risk management.