Investigation of AC loss and current distribution in co-axially assembled cable conductor of multiple HTS tapes

Numerical studies on characteristics of the inter-layer current distribution and the AC losses in co-axial multi-layer cable conductors with superconducting magnetic shields were performed by using the model developed by our previous study. The inter-layer current distribution and AC loss dependencies on the twist pitches, the diameter and the numbers of the superconducting layers of the cables were investigated. The analytical results showed that the magnetic field produced by the shielding currents strongly affected the current distribution and the AC losses of the cable. Based on the model, the optimized cable structures to achieve the uniform current distribution and to reduce the AC losses were studied. Examples of the optimized structures obtained by our model were presented and compared with those obtained by the conventional electric circuit model.