Partial discharge activity in electrical insulation for high temperature superconducting (HTS) cables

This paper discusses electrical insulation characteristics of liquid nitrogen (LN₂) / polypropylene (PP) laminated paper composite insulation system for the practical electrical insulation design of high temperature superconducting (HTS) cables. Partial discharge (PD) inception, propagation and breakdown (BD) characteristics under ac voltage application were obtained and discussed at atmospheric and pressurized conditions. Experimental results were analyzed quantitatively and revealed that void- type discharge was categorized as an important form of discharge to characterize the transition of PD activity leading to BD.