Fabrication and Critical Current Evaluation for HTS Twisted Cables Consisting of Soldered-Stacked-Square (3S) Wires

Abstract

High temperature superconducting (HTS) conductors or cables can be considered as a significant candidate in various large-current HTS applications. To develop large-current HTS conductors or cables, HTS wires of small square dimension have been suggested and studied in our group, and the wire is named Soldered-Stacked-Square (3S) wires. Based on 3S (2+10c)-wires composed of two HTS tapes and ten copper tapes, a novel HTS twisted cable structure named “2mm-7-cable” including seven (2+10c)-wires was firstly proposed in this study. This structure is most similar to the cable in conduit conductor (CICC) structure of low temperature superconductor (LTS). To begin with, we introduced the fabrication process of the 2mm-7-cables, including preparation of soldered-stacked-square (3S) wire, winding copper wire process, twisting and cabling process. Then, their critical current performance was evaluated experimentally. The test results of critical current show that when the voltage-lead is directly connected to the surface of the (2+10c)-wire after removing the copper wires of both ends, the measured resistance of 2mm-7-cable will be greatly reduced. And the summation of the critical currents of seven (2+10c)-wires are almost identical to the one of the 2mm-7-cable. Thus, the feasibility of the fabrication method for the novel HTS twisted cable is partially verified in this study.