The pollution flashover of ac energized post type insulators

This paper investigates the application of a theoretical model to predict the flashover of practical post type insulators. In particular, the model is applied to two 132 kV designs with different profiles and leakage path lengths. It is found that arc shortening due to inter-shed and inter-rib flashover and arc movement results in a significant deterioration of the pollution performance of the insulator. The theoretical results are confirmed by salt fog tests and field experience.