[1] Furukawa Elect Corp Ltd, Telecomun & Energy Labs, 6 Yawatakaigan Dori, Ichihara, Chiba 2908555, Japan
[2] Kyoto Univ, Dept Elect Engn, Nishikyo Ku, Kyoto 6158510, Japan
[3] Fujikura, Energy Technol Res Dept, Adv Technol Lab, 1440 Mutsuzaki, Sakura, Chiba 2858550, Japan
[4] Showa Cable Syst Co Ltd, Superconductor Technol Ctr, Chuo Ku, 1-1 Minami Hashimoto 4 Chome, Sagamihara, Kanagawa 2520253, Japan
[5] Sumitomo Elect, Superconduct Technol Div, Konohana Ku, 1-1-3 Shimaya, Osaka 5540024, Japan
[6] Tokyo Elect Power Co Holdings, TEPCO Res Inst, Tsurumi Ku, 4-1 Egasaki Cho, Yokohama, Kanagawa 2308510, Japan
[7] Japanese Elect Wire & Cable Makers Assoc, Japan Natl Comm IEC TC90 Superconduct, Chuo Ku, Konwa Bldg,1-12-22 Tsukiji, Tokyo 1040045, Japan