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A new dynamic 3D FEM model of arc propagation on cap-and-pin polluted insulator to predict DC flashover voltage

Mathematical models are an essential element in the calculation of the outage rate of overhead lines due to pollution level. Several dynamic and static models have been proposed to explain the mechanisms underlying the propagation of arc on polluted surfaces. Dynamic approaches are more realistic since most of the parameters involved in the arc development process tend to change instantaneously with time. The aim of this work is to improve the dynamic DC flashover model by refining the residual resistance calculation using threedimensional Finite Element Method (3DFEM) model of the pollution layer. This model which depicts a real cap-and-pin insulator surface is implemented by COMSOL Multiphysics software. The calculated resistance is then introduced in an iterative dynamic model which is based on resistive electrical circuit model and electrical field propagation criterion. Besides the flashover voltage, the simulation results allow us to determine various arc characteristics evolution versus time such as leakage current, arc velocity, and arc voltage. The Flashover voltage simulation results provided by the model are quite satisfactory compared to static model reported in the literature.