The pollution flashover of AC and DC energised cap and pin insulators: the role of shortening of the arc

This paper investigates the application of theoretical models to predict the flashover of practical cap and pin insulators. It is found that the arc constants vary with pollution severity and that this variation can be attributed to the arc across the dry bands not following the insulator surface, but taking shorter routes. This analysis is done for AC and DC energised cap and pin insulators by comparing the results obtained, using the appropriate theoretical models, with test data