29th Symposium on Fusion Technology (SOFT 2016)

P2.093 Commissioning of the Wendelstein 7-X Quench-Detection-System

6 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 93

Poster E. Magnets and Power Supplies P2 Poster session

Speaker

Matthias Schneider (Max-Planck-Institut für Plasmaphysik)

Description

The Quench-Detection-System of the fusion experiment Wendelstein 7-X detects quench events within the superconducting magnet system constructed of 50 non-planar and 20 planar coils, 14 current leads and the bus bars. In the event of a quench the QD-System triggers the power supply of the magnetic system to shut down. The QD-System monitors the superconducting system by 486 Quench-Detections-Units. The first step of the commissioning phase was to check the wiring betweenthe QD-Units and the superconducting magnetic systems, current leads and bus bars.Not only the electrical connection had to be checked also the correct contacting points of all wires on the magnetic system had to be verified. The verification of the correct connecting points was important to prove the unbroken protection. The next commissioning step was to adjust the balance of the QD-Units voltage measuring bridge. Two layers of all planar and non-planar coils are monitored through this bridge. Because of design deviations an inductive difference exists between bothlayers. This asymmetry is compensated by balancing of this bridge. The superconducting sections of the current leads and bus bars are monitored by a simple voltage measuring. The last commissioning step was to parametrise the detection criteria. A quench is detected by a defined difference voltage level U > 0 and a integration time T >= 0.If both criteria are fulfilled a quench event is detected and the magnetic power supply is triggered to shut down. The paper describes the background, boundary conditions, measurement methodand results of the wire check. In detail is described the used proceeding to balance the QD-Units and the lessons learned as well as the identified and used quench detection parameters.