Dynamic arc modeling of DC flashover under contaminated conditions

A dynamic model which explains the contamination flashover of insulators is developed. It takes into account the instantaneous changes in the parameters of arc propagation. This model is based on the concepts summarized in the review paper by F.A.M. Rizk (1981) and the dynamic features reported in a paper by S. Anjana and C.S. Lakshminarasimha (1989), where Mayr´s equation is used to calculate the instantaneous change in the arc parameters. The arc propagates when the net input energy to the arc is sufficient to sustain it. The arc gradient E_arc is calculated either from analog models, such as the electrolytic tank, or from the relationship E _arc=I_arc×R_arc . The flashover voltage is computed for a post and suspension insulator with uniform pollution layer (worst-case condition). The influence of arc parameters such as arc density, initial arc length, and arc resistance is discussed