Source strength impact analysis on insulator flashover under contaminated conditions

A mathematical model that considers the source-insulator interaction is presented for modeling flashover of outdoor insulators under contaminated conditions. The model is applied to suspension and post type insulators with wettable surfaces. Several IEEE test cases of practical power systems have been evaluated using PowerWorld
^®
to estimate the source strength. Results included in this paper show that significant difference exists in the probability of flashover in actual power systems when compared to laboratory results using sources that satisfy international standards. It is found in this paper that flashover in service can occur at much lower levels of contamination than predicted by international standards.