Simulation model of flashover process on insulator string exposed to the impulse voltages

The paper deals with a mathematical simulation model for the prediction of flashover voltages of suspension insulator string during the high voltage impulse voltage tests, when various shapes of impulse voltages are applied. The physical background of the streamer-leader flashover process with assumptions and constrains needed for mathematical simulations is described. The approximation of electric field distribution during the flashover process is carried out by finite element method calculation. After that, the final computer algorithm is proposed and verified on real experimental measurements in the high voltage laboratory. The realized computer program allows to calculate the flashover voltage for various shapes of impulse voltages and moreover, to take into consideration an influence of pollution layer on insulator surface. Presented comparison with experimental measurement confirms that the proposed simulation model can give reasonable accurate values of flashover voltages which are sufficient for test engineers.