Analysis of causes of outdoor insulators damages on HV and UHV transmission lines in China

In this paper the statistical analysis for the causes of outdoor insulation accidents of AC and DC high-voltage transmission lines in China were described. This paper focuses on lightning strike, pollution flashover, icing, birds-caused damage, and other factors which may damage the safe operation of power transmission lines. This paper also analyzes the service situation of insulators, the reasons of damages as well as the development tendency of insulators with different types in transmission lines.