Papers by Author: Yutaka Yamada

Abstract: Many technical problems need to be developed in order that a high temperature superconducting (HTS) cable will use in a real power network. A second-generation HTS tape (YBCO coated conductor) has potential of making its AC loss lower than that of a BSCCO tape because the superconducting layer of a YBCO tape is thinner than that of a BSCCO tape. Moreover, cost of a YBCO tape will become less than that of a BSCCO tape in future because quantity consumed of costly component (such as silver) in a YBCO tape is less than that in a BSCCO tape. Considering these, an HTS power cable that using YBCO tapes will become an economical choice compared with a conventional XLPE cable or a BSCCO HTS cable. HTS power cables using YBCO tapes have been developed in the Japanese national projects. HTS conductors were fabricated by Furukawa and YBCO tapes were manufactured by ISTEC SRL and Chubu Electrical Power Company, and these properties were measured.

Abstract: In the present 5-year national project since 2003, the development of YBCO coated conductors (CC) has advanced rapidly. The high performance processing group of SRL-ISTEC and Fujikura Ltd. has been working on the long tape of the PLD-YBCO superconductor on the IBAD-Gd2Zr2O7 buffered substrate tape. Very recently the SRL group achieved the highest value on the product of Ic x L in the world, 51,940 Am (212 m x 245 A). Fujikura Ltd. also realized the longest buffered substrate tape of 500m long IBAD tape and obtained a 200 m long coated conductor with Ic value of 88 A. In the low cost processing group using MOD, CVD and so on, the high Ic value of 525 A was obtained by SRL using the TFA-MOD method on the IBAD substrate. The 45m long TFA-MOD tape was also obtained with the Ic value of 155 A by Showa Electric Wire and Cable Company. Similarly 100- 200 m class long tapes were also obtained by the MOCVD (Chubu Power Electric Company) and PLD-HoBCO processes (Sumitomo Electric Industry Ltd.). Both groups above are further developing for the final goal of 500 m long tapes with the Ic of 300 A/cm-w at the production rate of 5 m/h. Furthermore, the feasibility study for the application has started due to the above success of long tape production. Several kinds of preliminary experiments using long coated conductors are now in progress for the power applications such as (1) Power Cable, (2) Transformer, (3) Motor and so on.