Study on Quench Protection Method With Regards to Normal Transition Behavior for HTS Coil

This paper presents the quench detection method with using normal transition behavior for HTS coil. If the HTS coil starts to propagate a normal zone by an initial quench, it will be recovered the superconducting state or runaway thermally. These behaviors were mainly determined by variety parameters like the magnitude of a disturbance, HTS coil size, the structure of winding wire and cooling condition. However, the first step of detection or protection for coils should be started from detecting the presence of a non-recovering normal zone. This paper classifies the initial quench behaviors of HTS wires or coils as a model of 3-type tendencies, and suggests suitable detection techniques for each tendency with using the end-to-end voltage of coil. In additional, this method is able to detect a quench without a decisive criterion used at other quench detection methods. In order to confirm the validity of the method, we used the HTS sample coil wound with YBCO tapes. This paper presents these results and the quench protection properties with fabricated detection method.