Coupling Loss Time Constant Calculation of Cable-in-Conduit Conductor Considering Electromagnetic Load Cycle

On the International Thermonuclear Experimental Reactor superconducting fusion device, the Nb
₃
Sn composite strands have been applied to cable-in-conduit conductor to meet the impact of the magnet field about 12 T. The strain of the Nb
₃
Sn-based conductor main due to Lorentz forces leads to the change of coupling loss time constant. However, the effect exploration of contact properties considering electromagnetic load cycle on coupling loss time constant is insufficient. In order to calculate coupling loss accurately and quickly, a new calculation model of coupling loss time constant was presented in this paper, which is expressed in three parameters, i.e., cabling sequence ratio, contact resistance, and void fraction with electromagnetic force cycle. In this model, not only cabling sequence ratio was established, but also contact resistance and void fraction considering strain resulted from electromagnetic load cycle were obtained. Compared with numerical calculation using Gandalf and traditional method, the error of coupling loss calculated with the combination of cabling sequence ratio, contact resistance, and void fraction under electromagnetic load cycle is smaller, which is closer to the engineering measured value.