Three-Dimensional Numerical Study on Transport AC Loss of Soldered-Stacked-Square-Twisted (3S-T) Wire

High-temperature superconducting (HTS) soldered-stacked-square (3S) wire has been proposed as a novel potential structure for the second generation HTS wire. Twisted method is an available way to decrease the anisotropy and improve the performance of 3S wire in high field application. This paper presents a three-dimensional numerical model based on H-formulation for the 3S-twisted (3S-T) wire. AC loss is evaluated as an important parameter when 3S-T wire is applied in alternating current or magnetic field circumstances. Three different structures of 3S-T wires are considered, and the validity of the general model is verified by the corresponding experimental results. The results show that there is no significant eddy loss existing in the 3S-T wire. Moreover, if more HTS tapes are contained in 3S-T wires, the current distribution will be closer to elliptical shape and the current phase in different YBCO layers will be changed. The transport AC loss can be slightly reduced through the twisted method. The work in this paper will be helpful to understand the electromagnetic characteristics of 3S-T wire.