Electrical performance of composite insulators under icing conditions

Due to the substantial advantage compared to porcelain and glass insulators, Composite insulators have been widely accepted in electric power utilities worldwide. Compared with porcelain and glass insulators, the flashover performance of composite insulators is superior under the contaminated condition, whereas their icing flashover performance should be investigated further. As shown in previous studies, many factors influence the flashover performance of composite insulators under icing conditions. In order to figure out the factors that influence the flashover performance of insulators, experiments were carried out on icecovered energized and de-energized composite insulators under icing condition. The results show that the flashover performances of composite insulators are superior under energized condition compared with de-energized condition. Under energized condition, when icing is light, the flashover performance of different shed configurations is decided by creepage distance. When icing is moderate, the flashover performance of insulator is influenced by water freezing conductivity, shed configuration, creepage factor, and so on. When icing is heavy, most of the sheds are bridged and the configuration of the last few sheds near the high voltage end have important effect on the flashover performance.