Relation between impedance distribution and current imbalance in an insulated multi-strand superconducting cable conductor

We have been investigating the current imbalance problem comparing the calculated result obtained by the measurement of inductance distribution in multi-strand superconducting cable conductor using high accuracy LCR meter and the measured actual current distribution in it. So far, the measurement of inductance and that of actual current had been carried out at 1 kHz and at few Hz, respectively. As a result, the experimental result did not agree well with the calculated one. It was estimated that the discrepancy between both results was due to the error in the inductance measurement. So, this time, we have carried out inductance measurement more precisely at 100 Hz, and, we have also measured actual current at wider frequency range. From these results, it is concluded that the current distribution is very sensitive to the inductance distribution. Particularly, in multi-stranded conductors with higher magnetic coupling among the strands, such as a large scale and multi twisted cable conductor, the current distribution shows a very dynamic change with the frequency