FEM-based computation of flashover condition for a special three-electrode spark gap design

Three-electrode spark gaps are used in cases when controlled high-speed switching of heavy currents and high voltages is needed. In this paper the procedure for calculating the flashover condition for a special shape of a three-electrode spark gap is presented. The flashover condition is determined by the flashover voltage of the insulating medium and the electrical field intensity between the electrodes. The impact of the shape and the position of the third electrode, as well as the voltage connected to it, on the electrical field intensity, and consequently the fulfillment of the flashover condition has been analyzed