Test Set-Up to Study Current Distribution in AC Multistrand Superconducting Cables

Non—uniform current distribution among strands is believed to be a main cause of current degradation in multistrand superconducting cables at non—steady state conditions. To understand the phenomena the best way is the direct measurement of the current in each strand or subcable. The special test set-up to study current distribution in AC superconducting cables for commercial frequency use was developed. It permits to measure currents in six strands or subcables by two methods (pick-up coils and Hall sensors) at frequencies from 0 to 120 Hz and at currents from hundreds to thousands amperes. Detailed descriptions of experimental set-up, calibration, measurement procedures and some results of study of current redistribution in three multistrand superconducting cables are presented in this paper. It was found that current distribution among subcables is determined by the joint resistances with current leads.