Numerical simulation of current distribution in cable-in-conduit conductor for ITER TF coil

The critical current of a cable-in-conduit conductor (CICC) for an ITER TF coil was measured using the SULTAN test facility. It was found that a non-uniform current distribution was established due to a non-uniform joint resistance. To evaluate the critical current performance accurately, we used a solder-filled joint. To study the effect of this solder-filled joint on the current distribution, we used a lumped circuit model and a distributed circuit model for the conductor and the joint, respectively, and combined the two to develop a new analysis model. This enabled us to solve the distributed circuit equation using only a few iterations, resulting in considerable reduction of the calculation time. Simulation results showed that, although the current distribution was non-uniform due to the ramping current, it improved at the current sharing temperature. This indicated that the solder-filled joint effectively improved the current distribution.