Development of YBCO HTS cable with low AC loss

Abstract

High temperature superconducting (HTS) cables using YBCO tapes are expected to be more economical because AC losses will be much smaller than conventional cables. To reduce AC loss, 10 mm wide YBCO tapes were divided into five strips using a YAG laser. Using narrower strips and optimizing the space between the strips were effective in reducing AC loss. A 1 m conductor was fabricated, and AC loss was 0.048 W/m at 1 kA and 50 Hz. Based on the successful AC loss reduction in the 1 m conductor, we will fabricate a 10 m HTS cable with a three-layer HTS conductor, electrical insulation, and a one-layer HTS shield and cupper protection layer for overcurrent. In addition, we have developed a prototype of the HTS cable joint that can withstand an overcurrent condition of 31.5 kA for 2 s.