Influence of transport modes on AC loss characteristics of cylindrical single-layer conductors consisting of various HTS tapes

In high temperature superconducting (HTS) cable applications, AC loss is always a critical issue and an obstacle to the commercialization, and the cables are usually composed of conductors with cylindrical structure. To study the effect of the magnetic field distribution with noncircular shape on AC losses, four hexagonal single-layer conductors are prepared using BSCCO, YBCO, and YBCO-NiW tapes. Besides the BSCCO and YBCO conductors, conductors consisting of YBCO-NiW tape are tested with the Ni-W located in two positions that is the inside and the outside of the conductor. Moreover, we achieve the magnetic field of the noncircular shapes through various transport modes. The results show that AC losses of all conductors get a minimum in the simultaneous mode which means the six tapes of the conductor are energized together. For the BSCCO, YBCO, and NY conductor, the AC loss of the tape strongly depends on transport modes and the cylindrical configuration can obviously decrease AC loss. However for the YN conductor, the transport mode dependence is quite weak and the cylindrical configuration can hardly decrease AC loss. Furthermore, the AC losses of the YBCO conductor is optimal, and the AC loss of the YN conductor is the greatest because of the hysteresis loss of the NiW layers located outside of the conductor.