Investigation of Quenching Phenomena at the Joint between AC Superconducting Cable and Normal Conducting Plate and Optimization of Joint

通过三维数值分析和实验研究了交流超导电缆与正常导体板连接处的失超现象，并对其连接处进行了优化。本文的主要工作如下：1.交流超导电缆与正常导体板连接处三维电流分布分析方法的研究通过对外加电流和涡流的分别计算，提出了一种分析具有集肤效应的导体板连接处三维电流分布的新方法。2.工频下导体板连接处电流分布的测量采用改进的探针法测量导体板表面的电流分布。由于探头的输出信号很小（μ V级），所以采用零差法。3.接头优化通过考察接头形状和尺寸对电流集中度的影响，研究了接头的最佳接头。4.实验验证产生了最佳接头，并通过实验确定了最佳接头在不淬火的情况下流过的最大电流。

The quenching phenomena at the joint between ac superconducting cable and normal conducting plate is investigated and its joint is optimized by carrying out 3-D numerical analysis and experiments. The results obtained can be summarized as follows :1.Development for Analyzing 3-D Current Distribution at the Joint between AC Superconducting Cable nnd Normal Conducting PlateA new method for analyzing 3-D current distribution in the joint having such remarkable skin effect is developed by calculating impressed current and eddy current separately.2.Measurement of Current Distribution at Joint under Commercial FrequencyThe current distribution on the surface of the copper plate is measured using the modified probe method which is developed by us. As the output signal of the probe is very small (mu V order), homodyne method is used. The reason why the quenching occurs at the commercial frequency is also clarified by experiment.3.Optimization of JointThe optimal joint is investigated by examining the effects of the shape and dimension of joint on the concentration of current.4.Experimental VerificationThe optimal joint is produced, and the maximum current which flows in the optimal joint without quenching is clarified by experiment.