Title :
Quench Detection Method for Cryocooler-Cooled YBCO Pancake Coil for SMES
Author :
Ohnishi, H. ; Ishiyama, Atsushi ; Watanabe, Toshio ; Hirano, Naoki ; Nagaya, Shigeo
Author_Institution :
Dept. of Electr. Eng. & Biosci., Waseda Univ., Tokyo, Japan
Abstract :
In this study, we focus on a quench detection method for a cryocooler-cooled double pancake coil wound with an YBCO bundle conductor for superconducting magnetic energy storage. Because the local normal-zone propagation velocity is significantly slower in a high-temperature superconducting coil than that in a low-temperature superconducting coil, it is difficult to detect the local normal transition using a voltage between both coil ends. In the application of an YBCO coil for superconducting magnetic energy storage, quench detection is considered to be more difficult because of the noise of the converter or other equipment. Therefore, the normal transition and quench must be detected using some other method. A current detection method, which measures the current redistribution in the YBCO coil with hall probes, was proposed and verified to be able to determine the normal transition by the numerical simulations in the previous paper. In this study, on the basis of the current detection method, the experiments and numerical simulation were performed on a cryocooler-cooled small model double-pancake coil wound with an YBCO bundle conductor composed of four electrically insulated YBCO tapes. As the results, the current detection method was verified to be effective in detecting the local normal transition; Hall probes were used to measure the magnetic field and to estimate the current in individual YBCO tapes making up the bundle conductor.
Keywords :
barium compounds; cryogenics; high-temperature superconductors; numerical analysis; superconducting coils; superconducting magnet energy storage; superconducting tapes; yttrium compounds; Hall probes; SMES; YBa2Cu3O7-x; bundle conductor; cryocooler-cooled small model double-pancake coil; current detection method; high-temperature superconducting coil; local normal transition detection; local normal-zone propagation velocity; low-temperature superconducting coil; magnetic field measurement; numerical simulations; quench detection method; superconducting magnetic energy storage; Coils; Conductors; Current measurement; Heating; Probes; Yttrium barium copper oxide; Quench detection; YBCO bundle conductor; YBCO coil;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2012.2234180