Electromagnetic Field Analyses of REBCO Roebel Cables Wound Into Coil Configurations
We have been developing a model for numerical electromagnetic field analyses of REBCO Roebel cables wound into coil configurations, considering their three-dimensional structure. Electromagnetic field analyses were carried out for one-turn circular closed loop of a Roebel cable, one turn circular closed loop of a Roebel cable at the end of a stack of Roebel-cable loops which simulated a solenoid coil of a finite length, and an infinite solenoid coil wound with a Roebel cable. From the temporal evolution of the current distribution in the Roebel cables, ac losses were calculated. We studied the ac loss characteristics of Roebel cables in different locations in coils. The influence of the gap between turns on ac losses was discussed.