J model for studying AC magnetization loss in 3D cable structures

Flux penetration and AC loss are among the key problems in the application of high-temperature superconductors (HTSs). Through simulation, the value and distribution of AC loss in HTS equipment can be evaluated and optimized in the design stage, so as to ensure the reliability and stability of the equipment. At present, there are many algorithms for AC loss calculation that can be simplified to a two-dimensional model, but for the case of three-dimensional structure such as cable in a spiral structure, there are still some problems such as difficult meshing, difficult convergence, and low efficiency. In this paper, an upgrade of the two-dimensional J model to a three-dimensional J model is proposed, permitting effective calculation of the flux penetration and AC loss in the CORC cable. The reliability of the method is verified by comparing the calculated results with the analytic model and with experimental results. At present, this method can efficiently calculate a 3D CORC model with a total of 15 superconducting tapes in five layers. Also discussed is the feasibility of upgrading to calculate larger models.