Insulation structure design of the UV-preionization gas switch

Abstract

The insulation structure of the UV-preionization gas switch for LTDs (Linear Transformer Drivers) has been designed in this study. The surface discharge along the gas switch chamber surface problem has been studied to ensure the gas switch can be charged to 200 kV DC. Meanwhile, the structure of the gas switch ought to be designed compact, in order to lower the overall inductance of the UV-preionization gas switch for LTD. It has been found that surface discharge is most likely to occur at the connection part of the solid dielectric, the electrodes and the air according to the electric field intensity simulation by a two-dimensional electrostatic solver. Polycarbonate (PC) has been selected as the insulator for the gas switch by analyzing the electric field distortion extent and the machinery strength of the various kinds of insulators. A surface discharge experiment has been designed. The experiment measures the surface discharge voltage in various distinct conditions of the surface roughness, the surface discharge distance and the gas pressure etc. In analogy to the air breakdown voltage empirical formula (U=f(pd)), we fitted the surface discharge voltage formula for the product of surface discharge distance and the gas pressure. The chamber surface has been grooved since the surface discharge distance has to be lengthened. It has been found that the measure of raising the grooving width is more effective than the measure of raising the grooving length in preventing the surface discharge when comparing the experimental results of these two different grooving methods.