Modeling flashover of composite insulators under contaminated conditions

This paper presents a theoretical model for evaluating flashover performance of composite insulators under contaminated conditions. The model introduces several new features when compared with existing models such as, the formation of dry bands along the surface, variations in surface wettability and insulator shape. The model draws heavily from experimental measurements of flashover voltage and surface resistance measured under wet conditions of composite insulators with housings made from silicone rubber, ethylene propylene rubber and epoxy, as well as electric field computations. The model has been used to illustrate the dominant role played by shape and housing material in the flashover process.