Critical Current and Current Feeding Test of a 200-Meter High Temperature Superconducting DC Power Cable System

A 200-m high-temperature superconducting (HTS) dc power cable was constructed in 2009 and since then, we have performed six cooling cycle tests to evaluate its performance. Current feeding test is one of the most important issues for this evaluation. This cable has a three-layer coaxial structure. The inner two layers are used as positive (+) polarity, and only one layer in the outmost is used as negative (-) polarity for dc electric energy power, respectively. In the summer of 2014, we started the sixth cooling cycle test on the 200-m cable. After cooling down to liquid nitrogen temperature, we applied a dc transport current to the 200-m cable. In this paper, we will present the current feeding test in the 200-m cable together with the critical current measurements. The critical currents of HTS tapes are enhanced in the assembled cable compared with the manufacturer's specifications. No degradation occurred after the cooling cycles.