Investigation of an Optimum Structure for Mechanical Butt Joint of a Stacked HTS Cable With a Metal Jacket

Mechanical butt joint of a high-temperature superconducting (HTS) cable with a metal jacket has been investigated for a remountable HTS magnet where parts can be mounted and demounted iteratively to allow a superconducting magnet for a fusion reactor to be assembled and repaired. In this study, an optimum structure to achieve relatively uniform contact pressure distribution on joint surface in the mechanical butt joint was suggested by structural analysis. Then, joint resistance in mechanical butt joint of a stacked BSCCO 2223 cable with copper jacket was evaluated experimentally using an experimental setup established based on the structural analysis, to confirm effect of decreasing joint resistance by the joint structure. The results showed that the structure can reduce joint resistance to 140 nΩ for the BSCCO 2223 cable having 1 kA of critical current at liquid nitrogen temperature.