Experimental study of the voltage recovery characteristics of spark gap switch with different gases

This study uses a two-pulse method to determine the insulation recovery times of gas spark gap switch with different gas types applied in high power accelerator with water dielectric pulse forming line. Under the breakdown voltage of 450kV (the vacuum diode voltage is about 200kV), current 30kA, recovery characteristics of H2, N2, SF6 were studied. The recovery percentages of gas breakdown voltage and vacuum diode voltage were given. The results show that hydrogen has the best recovery characteristic. At a pulse interval of 8.8ms, recovery percentages of both gas breakdown voltage and vacuum diode voltage exceed 95%; for SF6, N2 with the interval of 25ms and 50ms, 90% voltage recovery percentages are obtained. The experiments also prove that the repetitive rate of high power accelerator with pulse forming line is mainly restricted by the gas switch repetitive rate; recovery percentages of the vacuum diode voltage and gas switch breakdown voltage are consistent; hydrogen switch can be employed for high repetitive rate high power accelerator with pulse forming line.