Numerical analysis of AC loss in a transposed high-Tc superconducting cable conductor

Abstract

Underground power transmission cables are mainly used in populated cities. They will become more popular in order to cope with the continuous increase in power demand. As underground space is already dense with facilities, it will be even more difficult to construct new tunnels for power cables. To make cables more compact is one of the important theme in cable technology. High temperature superconducting (HTS) materials have a potential to realize compact and high-capacity underground power cables because of their high critical current density, which is more than 1, 000 times larger than the operating current density of conventional power equipment. Since HTS power cables require liquid nitrogen cooling system, it is important to understand AC loss characteristics and to reduce the loss produced by FITS materials carrying alternative current.
High temperature superconductors have I-V characteristics well represented by a power law. Such non-linear characteristics as well as complicated conductor structures make it difficult to estimate AC losses by theoretical approaches. Numerical methods are promising for quantitative analysis of the problem. We have already developed a new algorithm to deal with superconductors having power law I-V characteristics using finite element method. Using this code, we analyzed current distribution and AC loss characteristics of a transposed HTS cable conductor consisting of round wires, and discussed the effect of their transposition.