Influence of the multilayer HTS-cable conductor design on the current distribution

The work presents the basic principles of the multilayer cable conductor de sign to achieve the maximum current-carrying capacity and the minimum losse s in a superconductor and constructive cable elements. The multilayer condu ctors of two to ten layers are analyzed. The results show that the traditio nal core design with alternative winding directions from layer to layer is useful only for two-layer conductor. The conductor with more layers must ha ve either the layers wound in one direction but with different pitch length s or two layer groups wound with different pitch lengths. Only for these ca ses, the balanced design can be realized and current distribution will be u niform. In such balanced design, the interlayer electrical voltage and as a result, the coupling losses, are absent and interlayer electrical insulati on is not needed. The recommendations to achieve the maximum critical curre nt as a function of conductor dimensions are derived. (C) 1998 Elsevier Sci ence B.V. All rights reserved.