Cryogenic Electrical Insulation and its Advantage

This paper summarizes the cryogenic electrical insulation with polymers and its interesting features. At cryogenic temperature, polymers show high electric strength, extremely higher ac treeing inception voltage, low tanδ, no thermal and chemical degradation, no water tree degradation, very limited space charge injection and resulting high short-circuit treeing inception voltage, etc. Based on these features, we can call polymer at cryogenic temperature as “super electrical insulator". Water is an enemy of electrical insulation at room temperature, but at cryogenic temperature it is frozen and becomes an electrical insulation material. A paper-ice composite insulation system shows superior electrical insulation performance compared with conventional paper- liquid nitrogen system and is expected to be one of good candidates for cryogenic electrical insulation system.