Current Limiting Characteristics of Parallel-Connected Coated Conductors for High-T_c Superconducting Fault Current Limiting Transformer (HTc-SFCLT)

K.Omura, H. Kojima, N. Hayakawa, F Endo, M. Noe, H. Okubo

Abstract—We have been developing Superconducting Fault Current Limiting Transformer (SFCLT) as a superconducting transformer with current limiting function. As the Step-5 of the SFCLT project for the up-graded ratings of current and voltage, in this paper, we focused on the up-grading of current by parallel-connected YBCO coated conductors. Based on the asymmetric configuration of coated conductors, different parallel connections were tested and evaluated in terms of critical current level and current limiting characteristics under large ac current at 77 K in liquid nitrogen.

Index Terms—YBCO coated conductor, superconducting fault current limiter, superconducting transformer.

Manuscript received August 19, 2008.
This work was supported by the Grant-in-Aid for Scientific Research (S) of the Ministry of Education, Culture, Sports, Science and Technology, Japan.
K. Omura is with the Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya 464-8603, Japan (phone: +81-52-789-4443; fax: +81-52-789-3143; e-mail: oomura@okubo.nuee.nagoya-u.ac.jp).
H. Kojima, N. Hayakawa and F. Endo are with the EcoTopia Science Institute, Nagoya University, Nagoya 464-8603, Japan (e-mail: h-kojima@esi.nagoya-u.ac.jp; endo@esi.nagoya-u.ac.jp; nhayakaw@nuee.nagoya-u.ac.jp).
M.Noe is with the Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany (e-mail: Mathias.Noe@itp.fzk.de).
H. Okubo is with the Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya 464-8603, Japan (e-mail: okubo@nuee.nagoya-u.ac.jp).

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