Design and Experimental Research on Self-Shielding DC HTS Cable Model With Large Current Capacity

DC high-temperature superconducting (HTS) cable has advantages over the ac HTS cable in the power transmission due to its zero Joule loss, higher current capacity, and controllability. To minimize the magnetic field influence and critical current degradation in dc HTS cable, we have ever proposed a new structure of dc HTS cable that is, self-shielding dc HTS cable which has interleaved winding configuration. In this paper, in order to solve the difficulty of current lead connection with HTS layer in the cable terminal with multilayers, we put forward a new kind of terminal configuration which can make the current in each layer being controlled individually and avoid soldering in terminal as well as be convenient for installing and disassembly. With this kind of terminal connection method, a dc HTS model cable with eight layers and 1900 mm in length is fabricated and tested in liquid nitrogen temperature. Uniform current distribution among layers is realized by adjustable resistance connecting with each layer. The experimental results show that the critical current degradation of self-shielding dc HTS cable is only 7% compared with the critical current in self-field while the traditional structure of dc HTS cable is about 20%, which indicates that the self-shielding cable can promote the current capacity effectively with lower critical current degradation and save more HTS tapes in the application of power transmission. So, this kind of cable with a thinner insulation layer is suitable for mid- and low-voltage situations, especially for industrial and ship situations where large current and low voltage are required.