Influence of Cabling on Current Characteristics of Round MgB2 Wires With Different Design

MgB 2 superconductors are currently considered as a prospective for different applications, in particular for use in high-current superconducting electrical power lines. The MgB 2 superconductors are rather sensitive to the strain that unavoidably occur during a cabling process, that is why a standard cabling machine should be adapted for minimization of strain before fabrication of cables based on MgB 2 wires. We performed the comparative study of critical current gradation of two round ex situ MgB 2 wires during the fabrication the model 18-strand cable. Both wires were produced by the Columbus superconductor and differ by mechanical properties, matrix composition, and initial critical current. Our cabling machine was previously modified for minimization of strain on the base of calculations of strains dependencies on bending and twisting of MgB 2 wires. Mechanical properties of MgB 2 wires were analyzed as well. The changes of critical currents of both wires during the 18-strand cable fabrication and insulation were measured. The results of calculations, critical currents tests, and mechanical properties are presented and discussed.