Abstract
Thermomagnetic instability in superconducting wires composing multi-strand cables is a problem in development of cables with large current capacity. This paper clarifies quench property of AC superconducting wires in distributed magnetic field which is applied to strands in the cable, and stabilization of the AC superconducting wires considering the effect of the longitudinal magnetic field or fraction of copper embedded in the strand.
First, the degradation of quench current of CuNi/NbTi superconducting wires in distributed magnetic field is exhibited with simple test samples. Second, the quench property of the strand in a (6+1)3 cable and the optimal twist pitch of the cable for high stabilization are discussed. Last, the effect of copper on the quench property of the strand and the appropriate fraction of the copper for the suppression of the quench current degradation in the distributed magnetic field are discussed.
