Study on Protection of HTS Coil Against Quench Due to Temperature Rise of Long Part of HTS Wires

Generally, high-temperature superconducting coated conductors (CC) are hard to be quenched by local and transient disturbances during normal operation because of the high temperature margin and high heat capacity of the conductor. However, the CCs still have possibilities of unexpected quenches originated by the appearance of local defects due to repeated mechanical stresses, and by temperature rise of the long part of the CCs due to malfunction of the cryogenic system, for example. In this work, the hot spot temperature of a CC with copper stabilizer during quench protection sequence is calculated by a numerical analysis for quenches by both of the origins mentioned above. The practical amount of the stabilizer is discussed not to over-protect but for a coil system to surely survive from sever damages caused by quenches considering quench origins.