This review paper describes the author's view of superconductor applications for electric power system, who was one of the planners of MITI/AIST Project of R & D on Power Applications of Superconductor Technology. In the near future, the power system in Japan will require critically new technologies to overcome the foreseenable difficult problems. Considering the system character, the first step to introduce superconductor technology in the power system should be to “superconductorize” the existing apparatuses in the system, with some analogy to biological evolution. According to a general way to commercialize new technology, the R & D of superconducting generators, which will increase not only generating efficiency but also system stability enormously, are under way, steadily step by step, by the Project team. These R & D works are believed to lead us in the future to “totally superconductorized power system, ” which has the highest efficiency, reliability, stability, availability and economy.
The application of superconducting technologies to electric power apparatuses is very important from the viewpoint of not only the promotion of energy and resources saving but also the improvement of power system stability. Super-GM was established in September, 1987 in order to proceed the research and development (R & D) on application of superconducting technologies to power apparatuses and Super-GM R & D project, which is sponsored by New Energy and Industrial Technology Development Organization (NEDO) under the Moonlight Project of Industrial Science and Technology, Ministry of International Trade and Industry, started from FY 1988 for a scheduled period of eight years. As to R & D on superconducting generator, the basic designs and analyses of 70MW class model machines and the research on element techniques concerning superconducting field winding, structural materials of multi-cylindrical rotor, warm damper, rotating cooling characteristics, helium transfer coupling and air gap armature winding of superconducting generator were conducted in FY 1988 and 1989, and many basic results were obtained. At present, R & D step is proceeding steadily from the research on element techniques to the examinations for manufacturing techniques using partial models such as field winding model, multi-cylindrical roter model, rotating cooling model, helium transfer coupling model and armature winding model for the manufactures and demonstration tests of 70MW class model machines. In this paper, the current situation of R & D on superconducting generator carried out by Super-GM is presented.
The application of a direct numerical analysis to the superfluid phenomena is attempted. The propagation of a second sound wave and the evolution of a finite amplitude thermal wave into a shock wave are simulated by applying the finite difference scheme to the two-fluid equation for superfluid helium (He II). Typically three types of thermal shock waves, that is to say, a front shock, a back shock and a double shock, are well simulated. The results, however, suggested necessity for introducing the effect of the interaction of a flow field with a tangled mass of quantized vortices to the governing equation in the breakdown state. The effect is taken into account on the basis of the Gorter-Mellink mutual friction formula modified to include an unsteady feature for the simulation of the propagation of a thermal shock, and of a steady heating.