Current transfer length in individual superconducting tape and quasi-isotropic superconducting strand

• Published in: Fusion engineering and design 2021-12, Vol.173, p.112861, Article 112861
• Main Authors: Pi, Wei, Ma, Yuantong, Tian, Binyi, Meng, Yiran, Shi, Qingmei, Dong, Jin, Wang, Yinshun
• Format: Article
• Language: English
• Subjects: Copper; Current transfer length; Electric fields; High temperature; HTS tapes; Lap joints; Quasi-isotropic superconducting strand; Soldering; Superconductivity; Terminals; Three soldering methods
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2021.112861

•The QI-S strand could be applied to superconducting cable or high-energy physical magnets.•The current transfer length of the QI-S strand is analyzed by three-dimensional simulation. The centrosymmetric distribution of current and the curve of surface current integral value with distance are obtained.•The length of the current transfer from copper terminal to superconducting region is obtained by measuring the resistance between voltage taps in the experimental sample.•The current transfer lengths of the individual superconducting tape under the front and reverse contact situation are analyzed. The simulation results of front contact are compared with the calculated values of analytical method.•The current transfer length of the QI-S strand could be used for the connecting segment of the superconducting cable. In the practical applications, superconducting cable should be connected to the power supply by copper terminals. The lap joint between the superconducting cable and copper terminals has some significant effects on the current transfer length (CTL). Firstly, three kinds of soldering methods for an individual high temperature superconducting (HTS) tape are modeled and its CTL is calculated. Then, the distributions of electric field and current along a quasi-isotropic superconducting strand are simulated. Lastly, the CTL of a quasi-isotropic strand is measured by the distribution of electric potential along the strand. The results of simulation and experiment indicate different soldering methods have great influence on the CTL of the superconducting tape/strand.