Critical Current of the HTS Winding Wound With 12 mm YBCO HTS Tape

Wide 12-mm high-temperature superconducting (HTS) tapes are being used for HTS windings. The critical current of an HTS winding with a 12-mm HTS tape is calculated in this paper, with consideration of the nonuniform current distribution at the cross-section of the HTS tape. To calculate the nonuniform current distribution, the cross-section of the HTS tape is divided into small elements. The current at each element is calculated by using the I_c - B relation and n-value, which are measured in this paper. A pancake winding wound with a 12-mm YBCO tape is constructed and tested to confirm the validity of the proposed calculation method. The minimum critical current of the 12-mm YBCO tape is 240 A, and the number of turns of the pancake winding is 100 turns. The results of test indicate the need to consider the nonuniform current distribution in the calculation of the critical current of a pancake winding using the 12-mm HTS tape. Unlike the 4-mm HTS tape, the 12-mm HTS tape shows that the current is limited at the innermost turn of the pancake winding.