Electrical breakdown of vacuum insulation at cryogenic temperature

An experiment on the breakdown of vacuum insulation was performed for the development of cryocables and other cryogenic electrical apparatus. The influence of conditioning, pressure, gap spacing, electrode material and voltage waveshape on the breakdown voltage of vacuum insulation was measured at room temperature and at cryogenic temperature respectively. The results indicate that cooling the high-voltage sphere electrode enhances the breakdown strength of vacuum insulation, and that in general, almost all effects of electrical breakdown of vacuum insulation at room temperature are reproduced at cryogenic temperature at somewhat higher voltage. The close correlation between the low-temperature and room-temperature breakdown voltages of large vacuum gaps is explained from the point of view of microparticle-initiated breakdown theory.>