Triggered three-electrode spark gaps

Comparative analysis of the characteristics for the gas insulated three-electrode spark gaps and vacuum insulated three-electrode spark gaps is presented in this paper. The experimental part of this paper includes the testing of spark gap models. Two spark gap types were tested: one having the third electrode inside the main electrode and one having a separate third electrode, both being insulated by vacuum or gas (under pressure, providing the same operating voltage as for a vacuum insulated spark gap). Both types of spark gaps were theoretically sized in the optimal way. Several characteristic are determined experimentally: (1) the influence of the gas and vacuum insulation parameters on the spark gap functioning and (2) the influence of the rate of rise and injected energy of the triggering pulse on the spark gap functioning. Two types of gases were applied: SF/sub 6/ gas, N/sub 2/ gas and three vacuum (residual) pressures: 10/sup -1/ Pa, 10/sup -4/ Pa, and 10/sup -6/ Pa. Also, three electrode materials were used: copper, steel and tungsten. The spark gap switching time and delay time are measured.