AC losses in a superconductor for the quick response type 70 MW class superconducting generator

Abstract

We have been developing a 70MW class model generator aiming at a 200MW class pilot machine. The superconductor developed for the field winding of the generator has a configuration of double stranded cable, consisting of NbTi, Cu, and CuNi. Then, for the purpose of decreasing intra-strand A.C. losses, a strand with additional Cu-0.5wto/~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 additional fins in the Cu sheath with the cable without fin. The results show that both eddy current losses and coupling losses in the strands were considerably reduced by the additional fins in the Cu sheath.