Quench Detection for the Primary Windings of a 100-kA Superconducting Electric Transformer in the Conductor Performance Test Platform of the CRAFT

A superconducting electric transformer (SET) is a key element in the conductor performance test platform of the Comprehensive Research Facility for Fusion Technology, which has the capacity to provide around 100-kA test current for superconductor testing. Quench detectors based on voltage measurement is the considered solution for the quench detection in the primary windings (PWs) of the SET. One of the major problems to be encountered during the operation of the primary magnet systems is the expected inductive, coupled signals due to the current ramp up/down. For this case, Wheatstone bridge compensation can work. Regarding the hotspot temperature restriction, the quench detection threshold value and the holding time are given based on quench simulation results. Because the inductance of the PW is huge, the choice of dumping resistance plays a key role to ensure that the stored energy should be released safely if quench events occurred.