Experiment of current imbalance in superconducting cable strands

Superconducting cables which are composed of many superconducting strands have the problem of current imbalance. This causes the cables to quench at a current level below its design value. This paper proposes two different methods to solve the imbalance problem, one of which uses current lead resistance and the other one iron core. The current imbalance mechanism is investigated by using Ag sheathed Bi-2223 high temperature superconducting wires. The approach compares two different connection methods for superconducting wires and it shows that the contact resistance is the one important factor that causes current imbalance. The current imbalance correction method using iron core in liquid nitrogen was also experimented.