AC-LOSSES IN A SUPERCONDUCTOR FOR THE QUICK RESPONSE TYPE 70-MW CLASSSUPERCONDUCTING GENERATOR

We have been developing a 70MW class model generator aiming at a 200MW class pilot machine. The superconductor developed for the field windi ng of the generator has a configuration of double stranded cable, cons isting of NbTi, Cu, and CuNi. Then, for the purpose of decreasing intr a-strand A.C. losses, a strand with additional Cu-0.5wt%Mn fins in the Cu sheath has been developed. We carried out the test, and analytical approach of the A.C. losses. Then, we compared the cable of additiona l fins in the Cu sheath with the cable without fin. The results show t hat both eddy current losses and coupling losses in the strands were c onsiderably reduced by the additional fins in the Cu sheath.