Electric field analysis of insulating spacers for a superconducting gas-insulated transmission line

An essential component of the new superconducting power cable concept called Superconducting Gas Insulated Line (S-GIL) is the insulating spacer that ensures the position in the center axis of the cylindrical, grounded cryostat. The material choices and the design topologies for the insulating spacers are presented for both the rigid and flexible cables. The choice of the material for insulating spacers depends on the cryogen used as the coolant and the dielectric medium as well as several mechanical considerations including whether the cryostat is rigid or flexible. Electric field analysis using finite element method was conducted for maximum electric field for various combinations of spacer material and cryogen. The analysis allows selection of appropriate material for the insulating spacers depending on the cryogen used, which in turn depends of the specific application of superconducting cables and the operating temperature.