Flashover performance of HVDC iced insulator strings

Based on artificial icing test results, it was found that the dc flashover voltage of iced insulator strings was non-linear with different string lengths. An experimental formula of flashover voltage on iced insulators of different string lengths is introduced in this paper. Icing tests were carried out on different kinds of insulators including DC antifog, double-shed and three-shed insulators. Under serious ice conditions, the DC flashover voltages of the different types of insulator strings were very close. The flashover voltage of energized iced strings was a little higher than that of de-energized ones. Index Terms--Iced insulator string, dc flashover, flashover, overhead line.