Resistance of pollution in equivalent electric circuit of flashover

In flashover-modelling literature, researchers only take into account, the resistance of the pollution on the insulator, assuming that the current takes part in its totality and that the geometrical shape of its lines in the pollution does not have an influence on the phenomenon. In the paper, and after presentation of the equivalent electric circuit of flashover used in the literature, an experimental study and physical analysis are presented concerning this assumption in two sets of laboratory models: multidirectional models and circular-sector models. The results obtained allow us to confirm first that the form of the pollution and the distribution of leakage current lines are indispensable to flashover modelling; and secondly that flashover criteria and critical conditions in the literature are unjustified.