200 kV small gas switches with low inductance

A small tri-electrode gas switch and a small two-electrode gas switch are designed. Experiments for self-breakdown voltages of two-electrode gas switches and operating voltages of tri-electrode gas switches have been carried out in different conditions. The inductances of these switches have also been tested. The experimental results show the relation between self-breakdown voltages and gas pressures (0~0.30 MPa, relative) is nearly linear. The self-breakdown voltage of two-electrode gas switches with 11.9 mm gap and full of 0.25 MPa SF6 is up to 190 kV. The self-breakdown voltage by linear extrapolation can be up to 210 kV while the gap is 11.9 mm and inner SF6 pressure is 0.30 MPa. Operating voltages for tri-electrode gas switches with 11 mm total gap can be ranged from 90 kV to 200 kV by adjusting inner SF6 pressure from 0 to 0.30 MPa. Short circuit experiments reveal that the inductance of the two-electrode switch is about 20 nH and the one of the tri-electrode switch is about 22 nH. Thus the results tested for inductances are close to the values calculated.