Electrical coupling parameter reconstruction from system model in multistrand superconducting cables

Current distribution in multistrand superconducting cables has substantial influence on stability. Any analysis of current distribution requires knowledge of the electrical coupling parameters, (e.g., self and mutual inductances, and the interstrand contact conductance). In this paper, a new approach that reconstructs the parameters from distributed parameter circuit model of multistrand superconducting cable is proposed. The strand currents are measured by experiment and treated as known conditions. The unknown parameters are then extracted from the partial differential equations that describe the current distribution. The desired results are found to be the minimum norm least squares solution that best fit the system equations and minimize errors. A code is developed to implement this reverse identification process. The results are validated by substituting the reconstructed parameters to the system equations for simulation and then comparing with current distribution experiments. The parameters are also compared with those from conventional experimental methods, (e.g., DC four-point method to measure interstrand conductance). This method, using parametric identification theory, provides a way to evaluate the electrical coupling parameters in multistrand superconducting cables under different conditions (current density and frequency, mechanical loads, etc.). The calculated parameters can be used in analysis of current distribution and cable stability.