Design of Practical Superconducting DC Power Cable With REBCO Coated Conductors

The authors proposed an innovative superconducting dc power cable using the longitudinal magnetic field effect, i.e., a significant enhancement of the critical current density of a superconductor in a parallel magnetic field. It was expected that a cable with a high current-carrying capacity could be realized with REBa₂Cu₃O_7-σ (REBCO) coated conductors. However, the critical current density in most commercial coated conductors does not increase but slightly decreases with increasing parallel magnetic field. Nevertheless, the critical current density in the parallel magnetic field is remarkably higher than that in a normal in-plane magnetic field, and it is possible to construct a dc cable with a higher current-carrying capacity using this characteristic in comparison with conventional superconducting cables. In this paper, we propose a new design of dc power cable suitable for present commercial coated conductors. The optimal condition of the cable is discussed.