Current measurements of the individual strands in CICC magnet

Abstract

Non-uniform current distribution in CICC (Cable-In-Conduit Conductor) is one of the major concerns for developing a successful magnet system. The three-strand CICC magnet has been constructed in KAIST (Korea Advanced Institute of Science and Technology) for the study of current non-uniformity. The magnet is equipped with a forced flow supercritical helium system at variable temperature to simulate the various thermohydraulic conditions of superconducting tokamak. Each strand of the magnet has its own shunt resistor to measure the current it carries during the de and ac operations. This paper describes an experimental apparatus and some current measurement results of the individual CICC strands. The unbalanced current distribution has been obtained directly from the shunt resistor voltage data. The surface contact resistance of the superconducting strands was small enough to allow current redistribution inside the conduit rather than at the terminal joints of the magnet.