A Multilayer Three-Phase Coaxial HTS Cable With Large Capacity and Low Loss

With the challenge of space size in urban densely populated areas and the increase in power demand, three-phase coaxial high temperature superconducting (HTS) cable has an attractive prospect in its compact structure and low loss. In order to minimize the proximity-effect among conductors of the same phase when the layers per phase increase, a new structure of cable composed of many three-phase groups is proposed, which decomposes the superconducting layers into many magnetically independent three-phase groups. Each three-phase group contains three-phase conductors composed of one or two layers per phase. The ac losses between the proposed and conventional HTS cables are compared by means of an analytical solution. The result shows that the new architecture greatly reduces the ac loss, and the efficiency of reducing loss is enhanced with the increase of layers. Therefore, the proposed cable is expected to replace the copper cables in some mid- or low-voltage levels and high-current conditions.