Superconducting technologies for next-generation electric power equipment; Jisedai denryoku kiki wo sasaeru chodendo gijutsu

This paper introduces mainly superconducting technologies used in a superconducting magnet energy storage (SMES) system, a fusion machine, and a superconducting generator as next-generation power equipment using superconduction. A superconducting coil uses suitably a force-cooled conductor constructed by a large number of stranded superconducting cables put in stainless steel tubes, with super-critical helium pressure-fed into clearances between cables and tubes. A super high-speed response magnetization type generator operates in direct current normally, but when a disturbance has occurred in a power system, it functions to suppress power oscillation by executing the so-called super high-speed response magnetization. In that event, the variable magnetic field is added onto the superconductor in association with variation in the magnetic field current. This variable magnetic field generates AC loss, and temperature rise due to the loss quenches the superconducting coil. Prevention of this event requires reduction in the loss. It is necessary to arrange properly a high-resistant layer of CuNi midway a loop made of superconducting filaments in a superconducting cable and copper. A proper arrangement was made possible by applying electromagnetic field analysis to the finite element method. 8 figs., 1 tab.