Electro-thermal dynamic model using the analytical arc parameters for the prediction of the critical flashover condition on the HVDC polluted insulator

This study presents the improved flashover dynamic model based on both, impedance criterion for the discharge propagation and energy balance criterion for estimating the discharge elongation. One main contribution is to study the electro-thermal model of flashover polluted insulators in DC case enabling to predict the instantaneous changes of the discharge characteristics such as leakage current, discharge temperature, arc resistance and the temporal evolution of their analytics parameters (A, N). To demonstrate the efficiency of the developed model, the authors applied it for flat plat insulators polluted only with NaCl and with mixed pollution (NaCl with insoluble materials). The recommended dynamic approach includes directly the temperature in the dynamic study of the flashover phenomenon since it is an essential parameter involved in the development of the discharge which has not been treated in the earlier studies for dynamic model. Of particular interest, it is important to note that both critical electrical parameters current (I-cr) and voltage (V-cr) calculated using the presented model are in good agreement with those of the experimental one.