Numerical modelings of superconducting wires for AC loss calculations

Superconducting properties of superconducting wires as well as the influenc e of their composite structure and twisting should be taken into account fo r their numerical modeling for AC loss calculations. Furthermore, complicat ed electromagnetic conditions in electrical apparatuses under which superco nducting wires an used influence their AC loss properties; superconducting wires carry their transport current and are exposed to the external magneti c field whose direction and magnitude vary spatially. A series of numerical models of superconducting tapes based on the finite element method has bee n developed. In each model, some of the above-mentioned factors that could influence the AC loss properties are taken into account. The models are for mulated with the current vector potential and the scaler magnetic potential (T-Omega method). Superconducting property is given by the E-J characteris tic represented by a power law. The current distributions in non-twisted an d twisted superconducting tapes carrying their transport current and/or exp osed to the external magnetic field are calculated with these models to est imate their AC loss. The current distribution in a short piece of supercond ucting tape exposed to AC magnetic field is also calculated. (C) 1998 Elsev ier Science B.V. All rights reserved.