Characterization of a Superconducting Gas Insulated Cable Under AC and DC Voltages

Performance of the insulation system of several model cables of Superconducting Gas Insulated Line (SGIL) was characterized under ac, dc ramp, and steady-state dc conditions. Experimental challenges in achieving the steady-state dc conditions under cryogenic conditions are discussed in the context of the large time constant. Experimental data on the limiting surface flashover voltages at room temperature and 77 K in the pressurized helium gas environment of S-GIL are presented. The results led to the conclusion on the promise of S-GIL for high ampacity and power density applications of electric transport platforms using medium voltage direct current power systems. The results showed that the S-GIL designs are suitable for applications of 10–30 kV dc power systems on electric aircraft and ships.