Electric field estimation of 220kV and 400kV polymeric insulators using ANSYS-LF used in transmission lines

Polymeric insulators are important components in a power system network. Failure of a single polymeric insulator poses serious threat to reliability of electrical utilities. Polymeric insulator due to its organic nature, degrades when various stresses act on it. This degradation eventually cause flashover, shortening its service life span. The degradation expedites when they work under contaminated conditions. Electric field distribution analysis is critical to access the failure of an insulator. If electric field reaches a critical value, it may result in flashover and eventually failure of the insulator. The present work concentrates on modeling of 220kV and 400kV polymeric insulators using ANSYS-LF software. Electric field evaluation was carried out on these insulators with and without corona disc. Results indicate that with insertion of the corona disc, there is a decrease in E-field values at the triplen junction which is below the threshold value. This is the prime factor which inhibits the occurrence of flashover, thereby improving its service lifespan under contaminated conditions. Further practical scenarios such as bird pecking, brittle fracture are studied. The studies highlight sharp increase in electric field values due to reduction in creepage distance. These studies will help the design engineer to select the suitable profile of the insulator to suit harsh environment.