Evaluation of the joint of superconducting tapes for railway feeder cable

Abstract

Developing superconducting cable for railway power transmission should lead to increased regeneration efficiency, reduced power loss, equalization of load between substations. In order to realize a kilometer-class superconducting feeder cable, on-site joint technique between superconducting feeder cables is required. For joining superconducting cables at railway construction sites, we conducted solder joining of superconducting tapes and its evaluation in the laboratory. We performed electromagnetic analysis of the joints by the finite element method in order to obtain a prospect of the optimum conditions of the solder joining. The target value of the joint resistance to 10−7 Ω class will be achieved by the solder joining regardless of the solder thickness and the joint length. Referring to the analysis results, mechanical and electrical properties measurement of the joined superconducting tape was conducted. From the results of the tensile and bending test, it is found that the solder joined superconducting tape with the lap length of more than 20 mm achieve the mechanical and electrical targets. These results are being utilized for cable joining at railway construction sites.