Experimental Investigation of AC Loss Characteristics under HTS Cable Electromagnetic Conditions

In a high-temperature superconducting (HTS) multi-layer AC cable, each layer of HTS tape is twisted cylindrically and exposed to the AC magnetic field produced by the AC transport current in the other layers. The magnetic field consists of a circumferential magnetic field and a longitudinal magnetic field. The magnetic field of each layer serves as an external magnetic field to the other layers. We measured the AC losses in twisted cylindrical samples comprising single layers of HTS cable transporting AC currents in external circumferential and longitudinal magnetic fields. The amplitude and direction of the combined magnetic fields were controlled via modifying the balance between the circumferential and longitudinal magnetic fields. We investigated the influence of the twist angle, and amplitude and direction of the magnetic field on the AC loss characteristics.