Application of IPTs to HTS cable conductor for uniform current distribution between their layers

Multi-layer HTS cables are apt to experience unequal current distribution among their layers, which is a main reason of the occurrence of ac losses. In this study, the application of IPTs, which are known to control the impedance among paths of a circuit using a magnetic shield effect, were proposed to solve the problems of HTS cables. A 2 layer HTS cable conductor and IPTs were fabricated using Bi-2223/Ag tapes with a 115 A critical current. The inner layer of the HTS cable conductor was composed of 10 HTS tapes with a pitch length of 18 cm and the tapes of the outer layer were placed straightly without winding pitch. Applying various magnitudes of currents to IPTs, we investigated the current sharing performance between layers of the HTS cable conductor. The applied current was distributed uniformly into the layers successfully. In addition, the performance of IPTs was examined under various conditions for the practical application in detail. From the results, the application of IPTs to HTS cables was considered to be a useful method to reduce ac losses.