Design Concepts and Experimental Results of Superconductor for Field Windings of 70mw Class Superconducting Generator

AC losses and critical currents of three types of superconductors were measured to evaluate the characteristics of the superconductors which are designed to meet the requirements for the field windings of a 70MW class superconducting generator with low response excitation system. The superconductors used for the test are compacted stranded cables composed of Cu-CuNi-NbTi strands, and have the same cable size. The cross sectional structure of the strands and matrix ratios for tested cables are different. This paper presents the results of the experiment and design concepts of the superconductor for the 70MW class generator.