Multiple-arc 100 kV 2.0 MA solid-dielectric switch

Problems arising during the development and operation of a 100 kV multiple-arc solid-dielectric closing switch for use in fast low-inductance switching applications are discussed. The switch has been operated at peak currents up to 2.0 MA and for a pulse length of 70 ¿s. The arc voltage is about 200 V and the switch inductance is 5 nH. Breakdown is achieved at any voltage using a high-current triggering system to rupture the main insulation in a time of 1.4 ¿s with a standard deviation of 0.15 ¿s. A theoretical model of the breakdown process based on an electromagnetically driven shock wave passing through the main insulastion is proposed which gives good agreement between theory and experiment. Tests on a similar 40 kV swich suggest that the maximum performance can be probably extended to about 8.0 MA for short pulse times and up to 1000°C at lower currents.