Evaluation of AC losses in cable conductors using thin superconducting tapes with non-uniform Jc distribution

The critical current density (Jc) in the YBCO superconducting layer in the typical coated conductor is known to be not uniform along a lateral direction of its cross section. Non-uniformity of Jc values in a superconducting layer is the dominant factors of the AC loss characteristics together with its geometrical shape and arrangement in an actual power device. In this study, we investigated the AC loss properties on the cable conductors using thin superconducting tapes with non-uniform Jc distributions through the numerical calculations. A rectangular cross sectional tape with large aspect ratio AR (>103) of its cross section and non-uniform Jc values along a tape width were used as the strand for assembling the single-layer cable conductors. Several tape strands were arranged on a cylindrical former, in a parallel way to the conductor length. Numerical calculation of magnetic field distributions and loss values under AC current transmission were performed, by taking into account the locally-varying Jc values in a tape strand and geometrical factors of conductors. The influence of non-uniformity of Jc values along a tape width on loss under AC current transmission in the cable conductors was discussed.