Title :
Quench Detection and Protection of Cryocooler-Cooled YBCO Pancake Coil for SMES
Author :
Ueda, Hiroshi ; Ishiyama, Atsushi ; Muromachi, K. ; Suzuki, T. ; Shikimachi, K. ; Hirano, N. ; Nagaya, S.
Author_Institution :
Res. Center for Nucl. Phys., Osaka Univ., Ibaraki, Japan
fDate :
6/1/2012 12:00:00 AM
Abstract :
In this paper, we focus on the quench detection and protection of a cryocooler-cooled pancake coil for SMES wound with a YBCO bundle conductor composed of laminated electrically insulated YBCO-coated conductors. Because the normal-zone propagation velocity is much slower in a high-temperature superconducting (HTS) coil than in a low-temperature superconducting (LTS) coil, the detection of the non-recovering normal zone using a voltage signal is quite difficult. Quench detection is considered to be more difficult during SMES operation because of the noise of the converter or other equipment. Therefore, a quench must be detected using some other method. In the previous paper, we showed that a quench in the coil could be detected by observing the transposition of the current in the bundle conductor caused by local normal transition. In this paper, based on this quench detection method, we investigate the transposition of current and the thermal behavior during the quench detection and the dumping of the stored energy by an external resistance in coils wound with a YBCO laminated bundle conductor for SMES and determine the appropriate stabilizer thickness of the YBCO-coated conductors.
Keywords :
barium compounds; cryogenics; high-temperature superconductors; superconducting coils; type II superconductors; yttrium compounds; SMES wound; YBCO; YBCO bundle conductor; YBCO laminated bundle conductor; YBCO pancake coil; YBCO-coated conductors; cryocooler-cooled pancake coil; high-temperature superconducting coil; local normal transition; low-temperature superconducting coil; normal-zone propagation velocity; quench detection; superconducting magnetic energy storage; Conductors; Numerical simulation; Superconducting coils; Superconducting magnetic energy storage; Yttrium barium copper oxide; Normal propagation; YBCO bundle conductor; protection; stability;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2011.2174578