Effects of electric field distribution on icing and flashover performance of 220 kV composite insulators

The energized icing of composite insulators has been studied by the researchers around the world, but not much about the effects of electric field distribution on their icing and flashover performance. For this purpose, the ice accretion and flashover performance of 220 kV composite insulators with two shed configurations on occasions of different electric field distributions considering the effect of grading rings are analyzed in this paper. The test results indicate that the intensity and homogeneous distribution of electric field have positive effects on the appearance, density and weight of ice; the improvement of electric field distribution after installing grading ring has more effects than the icing characteristics, such as quality, density as well as appearance of ice, on flashover voltages of ice-covered composite insulators; the icing flashover voltages are increased by the improvement of electric field distribution and the increasing ranges of icing flashover voltage were relied on shed configuration. Icing accumulation patterns have less effect on flashover performance of composite insulators with alternatediameter or widely spaced shed configurations.