Abstract
Excessive ohmic heating may damage superconducting wires when a quench occurs in a superconducting coil and hence it is necessary to detect the quench as fast as possible in order to protect the superconducting coil. We have proposed a new quench detecting method, which can detect an active power after a quench with high precision.
In this paper, in order to investigate the usefulness of the proposed method for HTS (High Temperature Superconducting) coils, quench detection tests of a small HIS coil are carried out and the results are presented. In general, HTS coils are not necessarily self-protective because quench propagation velocities in high Tc superconductors are slower than those in low Tc superconductors. Therefore a quench detecting method with high precision and fast response is required for HIS coils. Through the quench detection tests of a small Ag/Bi-2223 HTS coil, the usefulness of the proposed method is investigated. In addition, through the off-line quench detection tests of AC LTS (Low Temperature Superconducting) coils by the numerical simulation, the usefulness of the proposed method for AC LTS coils is also discussed.
