HTS Current Lead With Varying Cross-Sectional Area for Superconducting Magnet Systems

A HTS (High temperature superconductor) current lead, which provides an electrical connection between a power supply and a superconducting magnet, needs to be designed to minimize the heat leakage transferred to the cold end to save the cooling power of the superconducting magnet system. Since the heat leakage of the HTS current lead can be reduced not only through the material properties of the metal lead but also through structural analysis, we will introduce study results of the shape design method of a metal lead. We performed a numerical analysis based on a segment algorithm using the general solution of temperature distribution and heat leakage to mathematically express the design method. The results of the simulation revealed that the heat leakage at the cold end of the vapor cooled HTS current lead is determined by conduction, Joule heating and vapor cooling, thus demonstrating that liquid helium consumption can be reduced by adjusting the perimeter and hydraulic diameter of the metal lead. Based on these results, we performed a numerical analysis of the temperature distribution and heat leakage on a metal lead with an axially varying cross-sectional area. After the design, the metal lead was manufactured with the proposed method and applied to a 5 T class superconducting magnet system to evaluate the performance of the system. We compared the evaluation results to the simulation results to verify the feasibility of the proposed numerical analysis method. The study confirmed that the proposed metal lead design method can be applied to the superconducting magnet system to save cooling power.