Abstract:

Aiming at the few investigation of 220 kV icing composite insulator with four sheds at home and abroad, this paper analyzed the influence of icicle length and grading ring parameter, position on the electric field distribution of 220 kV icing composite insulator with four sheds with using the finite element analysis software Ansoftmaxwell. The results show that: （1） under the icing condition, when the gap between wet iced and large shed is 1 mm, the composite insulator bridged with icicle will not discharge when its large sheds, but it will have discharge risk under over voltage when the composite insulator is not bridged with icicle； （2） grading ring can significantly improve the electric field distribution between high voltage side and the first large shed； （3） the electric field distribution of the gap between high voltage terminal and nearby icicle can match best when grading ring’s vertical distant from fitting connection point is 0 mm, its outer diameter is 306 mm and pipe diameter is 36 mm.

Key words: icing, four sheds, composite insulator, length of icicle, grading ring, simulation analysis