Icing Flashover Performance of HVDC Transmission lines

Based on the data of artificial icing test for insulators, the DC flashover performance of ice-coated long insulator strings is presented. Research results show that the DC flashover voltage of insulator strings is nonlinear with respect to strings length. According to test results an experimental formula of ice-coated insulators’ flashover voltage varying with string length is put forward; and comparative tests of DC icing flashover voltages for different kinds of insulators, including DC anti-fog, double-shed and three-shed types of insulators as well as composite insulators are carried out, under serious icing condition the icing flashover voltages of different shed types of insulators are very close. The string length of insulators designed for ice-coated area of HVDC transmission lines and the measures to prevent the icing flashover are given.