Study of stacks of HTS-2 tapes as the main element of high-current superconducting wires for large-scale electromagnetic systems

This article is studying high-current wires based on high-temperature superconductors of the second generation (2G HTS) for large-scale winding of electromagnetic systems. A short overview of the main directions of development of highcurrent 2G HTS wires is given. Mathematical model and measuring equipment for studying the characteristics of highcurrent 2G HTS wires are presented. The results of theoretical and experimental studies of the critical current of the primary current-carrying elements of high-current wire stacks of 2G HTS tapes as a function of the number of tapes in the stack are analyzed. There had been described the technology for joining 2G HTS tapes into a single stack and the results of studies of the influence of tensile deformation on the critical current of 2G HTS tapes in stacks. The results of the development and research of the critical current of a prototype of a high-current VSS (V-Shape with Stacks) wire are presented. A two-stage scheme for the formation of multi-tape stacks for wire is proposed, in which, at the first stage, soldered stacks containing a limited number of tapes (3‒10 tapes) are formed, followed by the formation and soldering of the final stack. The results of overload resistance tests on a manufactured prototype of a VSS-type wire are presented. The prototype withstood an overload of 1.7 times of the critical current without changing its initial characteristics.