Development of assembled current lead prepared by the TFA-MOD processed YBCO tapes

HTS current lead have been prepared by the TFA-MOD processed YBCO tapes. A current lead unit is composed of 6 bundles stacked by 4 YBCO tapes, Cu end caps and a pair of stainless steel boards. The YBCO tape is 5 mm in width and around 130 μm in overall thickness. The YBCO superconducting layer with 1.5 μm is formed on oxide buffered layers on Hastelloy substrate tape. The critical current of 24 YBCO tapes ranges from 145 A to 166 A at 77 K and self-field. The YBCO current lead is assembled from the 4 current lead units in parallel. The transport current of 10 kA at 77 K was stably carried with no voltage generation on the YBCO tapes of the assembled current lead for 10 minutes. Rogowski coils were attached on 4 current lead units to evaluate current distribution of them. The current unbalance of 930 A occurred between 4 units at transport current of 10 kA.