Parametric estimation study of interstrand conductance in multi-strand superconducting cables

Interstrand conductance is a key parameter to understand the current distribution and stability events in multi-strand superconducting cables. In this paper, a new approach employing the parameter estimation method from system identification theory is applied to estimate the interstrand conductance from existing current distribution model based on experimental data of voltage differences at cable ends. Based on transient voltage measurements at cable ends this method estimates interstrand conductance conveniently and accurately under different conditions (temperature, cable length, cable compaction, etc.). The details of interstrand conductance between all combinations of sub-cables at different cabling stages were obtained. The influence of mechanical load on interstrand conductance was also studied. The experimental data sheds new light on how the mechanics of cable compaction and movement under simulated Lorentz load affects the electrical parameters, namely the interstrand conductance. The data are useful input for cable stability simulations and AC loss estimation, and the experimental method can be used to better characterize cables prior to magnet winding. (c) 2007 Published by Elsevier Ltd.