A comparative study on DC flashover characteristics of iced insulators with various electrial test methods

In this paper, the DC flashover characteristics of iced insulator strings were explored in the multi-functional artificial climate chamber through four methods, namely, the average flashover voltage method, the minimum flashover voltage method, the maximum withstand method and the 50% withstand method, with the typical DC porcelain insulator strings and composite insulators. The results indicated that the average flashover voltage and the minimum flashover voltage obtained respectively by the average flashover voltage method and the minimum flashover voltage method were in normal distribution; the 50% flashover voltages gained by the two test methods mentioned above were about 8.0%~9.8% and 3.8%~5.9% higher than that gained by the 50% withstand method respectively, which justified the feasibility of employing the U-curve method and the average flashover voltage method to study the flashover characteristics of iced insulators and their affecting factors.