Design study of model cable conductor by using HoBCO thin film tape

As a fundamental development of RE-123 cable conductor, the electromagnetic and mechanical properties of multi-layer spiral cable conductors using HoBCO thin film tapes were studied. The critical current of the HoBCO tape shows 95% performance at the 180 MPa tensile stress. Self magnetic field simulation of a 4-layer spiral cable conductor was carried out. AC loss calculation of the conductor with current capacity of 3 kA was also performed. The AC loss was calculated less than 0.5 W/m, which shows the possibility of low AC loss of HoBCO cable conductor. In the calculation, it was found that the gap between thin film tapes in the cable conductor makes an important role in reducing AC losses. Based on these design studies, fabrication of model cable conductor was performed. Several kinds of 1 m multi-layer spiral conductors and a 7 m 4-layer spiral conductor were made by using HoBCO tape and dummy tape. The stranding machine was especially applied to the 7 m 4-layer dummy cable conductor.