Prediction of flashover voltage based on leakage current under AC operating voltage

In this paper, a model to predict the AC flashover voltage of contaminated suspension insulators was presented. The prediction method is based on the maximum leakage current under AC operating voltage. Three kinds of widely used suspension insulators were tested in various contamination statuses such as pollution layers with different ESDD, different composition of the conductive components, different NSDD and different pollution distribution statuses to simulate the contamination statuses in nature. Effective ESDD was proposed and calculated. Influences of contamination statuses to maximum leakage current and flashover voltage were studied. Then, the relationships between flashover voltage and leakage current in these statuses are presented. Finally, considering the difference of insulator profiles, a new parameter is defined and a model to estimate the flashover voltage based on this parameter is developed. The model could be used to all kinds of suspension insulators in different contamination statuses and was validated by the test results.