Experimental investigation on current imbalance of stranded conductors

Multiple-stranded superconducting cable conductors have an essential problem-the so called current imbalance phenomenon. Generally, it is said that the current imbalance problem is caused by the inductance imbalance among strands. However, it does not explain why the inductance imbalance is generated in a symmetrically assembled strand and what is the main factor of current imbalance. In such a situation, the authors have experimentally investigated about the current imbalance problem using several experimental coils. Experimental results show that the current imbalance is strongly dependent on the magnetic coupling coefficient among the strands. In addition, it is also shown that the inductance distribution between the strands strongly depends on the cabling formation.