Pollution flashover calculation model based on characteristics of AC partial arc on top and bottom wet-polluted dielectric surfaces

A double-arc model, which considers the differences between characteristics of AC partial arcs on top and bottom surfaces, was proposed for predicting the flashover voltage of polluted insulators in this paper. The arc constants parameters, the arc reignition criteria, as well as the radii of arc columns in the proposed model were determined by measuring partial arcs on the top and bottom wet-polluted surfaces of a triangular glass plate separately. A "Π" type glass model was made to investigate the partial arc propagation process by using an ultra-high speed camera. It has been found that the arc length increased linearly with leakage current amplitude, the ratio of arc length increments on top and bottom surface was related to salt deposit density (SDD) rather than leakage current. Based on above-mentioned researching results, the double arc calculation model was established, and the calculated results were in good agreement with the experimental results.