Commissioning and first operating phases of the W7-X quench detection system

Abstract

Abstract The quench detection system of the fusion experiment Wendelstein 7-X monitors the superconducting magnet system consisting of 50 non-planar and 20 planar coils, 14 current leads and bus bars. The commissioning phase contained the wiring check of the electrical contact between the 486 quench detection units and the superconducting magnet system, the verification of an unbroken and overlapping monitoring, the balance adjustment of the quench detection unit voltage measuring bridge and the parameterisation of the detection criteria: detection level and integration time. During the operation phases there were two unexpected fast discharges initiated through the trim-coils and a fast decay of the bootstrap current. As a result the interplay of the detection level and integration time was re-evaluated. The quench detection system worked stable over the first both operating phases of W7-X, performed from 2015 to 2018. There were no failures of the quench detection units or other parts of the quench detection system.