Study on critical current of a flexible quasi-isotropic HTS conductor with high engineering current density

This paper presents a flexible quasi-isotropic High Temperature Superconducting (HTS) conductor with high engineering current density. The conductor consists of three components: the inner core is a twisted quasiisotropic strand (Q-IS) with a circular cross section achieved by symmetrically stacking four sub-stacks of HTS wires and four arc aluminum fillers, the middle component consists of copper layers constructed by copper wires spirally winding around the inner core, and the outer component consists of HTS layers constructed by HTS wires spirally winding around the middle section, which is similar to the manufacturing method used for HTS cable or CORC cable. After the three-dimensional finite-element simulation model of the proposed HTS conductor is established, the dependence of the magnetic field and critical current distributions on the twisting pitch of the inner Q-IS and the winding pitch of the outer HTS cable layers are analyzed. Consequently, the model HTS conductor is designed and fabricated, and the critical current of this HTS conductor is measured in liquid nitrogen. The results show that the simulated results are in good agreement with the experimental ones. It is predicted that this type of HTS conductor has potential applications in fusion magnet and power transmission.