The Study Of Soldering And Parallel Connection Of The YBCO Tapes

Since having higher critical current density and weaker anisotropy, the YBCO superconducting tape has been widely used in various fields. Withing the advent of electrical equipment which is produced by YBCO tapes, such as the superconducting magnets, superconducting cables and superconducting current leads, the higher performance requirements of YBCO tapes is needed. Limited to the preparation technology of YBCO superconducting tapes, we faced the problem that higher length and larger current-carrying capacity is required during the using of YBCO high temperature superconducting tapes. By soldering and parallel connecting with the YBCO superconducting tapes, we can solve these problems. The experimental analysis was carried out in this paper on the soldering technique of joints, and we did the experiments and simulations on the parallel connecting of the YBCO superconducting tapes.First, this paper introduced the characteristics of the YBCO superconducting tapes. The method of measuring the critical current of the superconducting tape was introduced by comparing two methods which are commonly used, the four-probe method and the non-contact methods. The thermal strain of YBCO tape that caused by the changing of temperature was measured experimental. We analyzed the effect of bending and tensile stress on the critical current of YBCO tapes, introduced the anisotropy of YBCO superconducting tapes by measuring the critical current in magnetic field,.Then the soldering joint of YBCO superconducting tape was studied. The soldering technique of YBCO joints was studied by comparing the resistances of joints with different soldering methods and different soldering length. At the same time, the experiments were carried out on the performance of YBCO soldering joints.We measured the thermal strain of soldering joints during the cooling process, analyzed the influence of the bending and tensile stresses on the critical current of the soldering joints, and the anisotropic of YBCO soldering joints under magnetic field.Finally, experiments and simulations were carried on the parallel of YBCO tapes. Respectively we took the electrical simulations and experiments on the parallel circuit of YBCO superconducting tapes under arranged horizontally and stacking arrangement, analyzed the self-regulating phenomenon of current in parallel circuit. The ANASYS software was used to analysis the changing of magnetic field of the YBCO superconducting tapes under parallel, and the minimum spacing was analyzed to reducing the attenuation of the critical current of YBCO tapes. According to the self-regulating phenomenon of current in parallel, the damaged superconducting tapes were repaired in experiments.