Analysis of inductance coefficients in multistrand cables: analytical, numerical, and experimental results

The evaluation of electrical coupling parameters in multistrand cables is a fundamental prerequisite for the calculation of current distribution and ac-losses in superconducting cables. The theoretical evaluation of these parameters requires a detailed description of the cable geometry. A code for the geometric description of generic multistrand multistage cables and for the calculation of the strand self- and mutual inductance coefficients has been developed. An extensive measurement campaign using straight and wound twisted multistage copper cables has been performed in order to validate the numerical model. An indirect measurement method has been used for the evaluation of the self-inductances of the wires in the straight cable. These results build a database that can be used to validate several numerical codes written in recent years for the analysis of electrical coupling parameters in superconducting cables.