The Electrical Insulation Characteristics for a HTS Cable Termination

A research on several characteristics such as volume breakdown and surface discharge of insulators for a termination of power transmission class high temperature superconducting (HTS) cable was performed. In this paper, we investigated the surface discharge of glass fiber reinforced plastic (GFRP) in the air, nitrogen gas (GN
₂
) and cryogenic nitrogen gas (CGN
₂
) media. The breakdown characteristics of these media were also studied. Experimental results revealed that flashover voltage greatly depends on pressure, temperature, the kinds of insulating media and voltages. However, it is shallowly affected by shape and material of electrode. The breakdown voltage of liquid nitrogen (LN
₂
), GN
₂
and CGN
₂
deeply depends on the shape and dimension of electrode, kinds of voltages and pressure. Moreover, the breakdown voltage of CGN
₂
and flashover voltage of GFRP in the CGN
₂
is also influenced by temperature and vapor-mist density of the gas