Termination cryostat for HTS power cable

In Korea the High Temperature Superconductor (HTS) power cable development project has been ongoing since July, 2001 with the basic specifications of 22.9kV, 50MVA and cold dielectric type as the first 3-year stage. The cryogenic system of the HTS cable is composed of FITS cable cryostat, termination and refrigeration system. Termination of HTS cable is a connecting part between copper electrical cable at room temperature and HTS cable at liquid nitrogen temperature. In order to design the termination cryostat, it is required that the conduction heat leak and Joule heating on the current lead be reduced, the cryostat be insulated electrically and good vacuum insulation be maintained during long time operation. The AC has been considered as an important parameter for the design of current lead for the HTS cable termination. Heat loads calculations on the copper AC current lead have been performed by analytical and numerical method and the feasibility study for the other candidate materials has also been executed. Since the resistance of the AC current lead has been affected by the skin effect, higher heat loads were generated in AC current lead compared to the DC current lead. The brass current lead generates higher heat load than copper current lead in both PLC and DC current lead.