Vacuum surface flashover characteristics of micro-stack insulators under nanosecond pulses

In this paper, micro-stack insulators with different ratios of insulator-to-metal (I/M) and embedded micro-stacks are studied using nylon as an insulating layer and conductive silver adhesive applied as a conductive layer. The electric field of insulators with a micro-stack structure is simulated. The results show that the electric field strength decreases and the dielectric strength improves near the cathode triple junction following an increase of the I/M ratio when the micro-stack insulators have the same conductive layers. The optimal ratio is found to be 0.61 at which point the dielectric strength increases by 2.1 times. In addition, the dielectric strength of insulators was compared while the surface has been ground along two different directions respectively. the result was found to be better when the surface is polished along the Y axis direction than X axis. The experimental results can provide a technical reference for the preparation, structural design and mechanism exploration of the micro-stack insulators.