Effects of HTS Tape Arrangements on AC Loss in Self-Shielding DC HTS Cable With AC Ripple Current

Critical current and ac loss of high-temperature superconducting (HTS) tapes are two important factors for the application of ac HTS power cables. Generally, the current in the dc HTS cable is a combination of main dc current and ac ripple current due to the use of rectifier. The ac ripple current distribution without proper adjusting would be nonuniform in each layer especially when the dc HTS cable layer increases; it may lead to high ac loss and poor transmission capacity. In order to understand the ac ripple current sharing among dc HTS cable layers, the inductance matrix of the cable layers was deduced based on the geometry configuration of a self-shielding dc HTS cable. In this paper, in addition to the uniform current design principle, a self-shielding dc HTS cable is also designed with the HTS tape arrangements of each layer optimized by taking the ratios of ac ripple current amplitude to critical current in each layer as equal for minimizing the ac loss. According to the design configuration and deduced inductance matrix, current in each layer and ac loss are calculated. The results show that it is necessary to use the optimized design in the dc HTS cable design and the equal ratio design is better than the uniform current design.