Critical Current Analysis of a Three-Slot Cable by Using of YBCO Tapes

Stacking tapes is one of the methods to increase the transport current of a superconducting cable. A three-slot cable (TSC) by using twisted stacked YBCO tapes is presented in this article. The YBCO tapes embedded in the slot generate an axial strain. Excessive strain leads to a degradation of the critical current. The strain equation is used to obtain the critical twist pitch, which is verified by embedding the tapes into some formers with different twist pitches. For a cable with a diameter of 6 mm and a YBCO tape width of 3 mm, the calculated critical twist pitch is about to 86 mm, which is consistent with the experimental result. Since the magnetic field generated by the stacked tapes causes critical current degradation, the Kim model is used to investigate the critical current of the proposed TSC. Calculation results for different stacking thicknesses compared with experimental results, the maximum error is found to be about 6%. In this article, the critical current of TSC cable is investigated to provide data for future applications of twisting multiple TSC cables to make cable-in-conduit conductors for a high magnetic field and high-current scenarios.