Data analysis of the strain gauges system of the W7-X superconducting coils

Tomarchio, Valerio; Riße, K.; Viebke, H.

doi:10.1016/j.fusengdes.2009.02.034

Cited by 12 publications

(7 citation statements)

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“…Some works have focused on the measurements of stress and strain in superconducting magnets at cryogenic temperature and under intense magnetic field during the coil excitation. To monitor the integrity of Wendelstein 7-X (W7-X) superconducting coils, Tomarchio et al [15] described the procedure adopted in the data analysis of signals produced by low-temperature strain gauges. Their results showed that the strain gauge system could measure appropriately the stress levels in the coil casings during self-field operation in a cold testing environment.…”

Section: Introductionmentioning

confidence: 99%

Strain-based quench detection for a solenoid superconducting magnet

Wang

Guan

2012

Supercond. Sci. Technol.

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In this paper, we present a non-electric quench detection method based on the strain gauge measurement of a superconducting solenoid magnet at cryogenic temperature under an intense magnetic field. Unlike the traditional voltage measurement of quench detection, the strain-based detection method utilizes low-temperature strain gauges, which evidently reduce electromagnetic noise and breakdown, to measure the magneto/thermo-mechanical behavior of the superconducting magnet during excitation. The magnet excitation, quench tests and trainings were performed on a prototype 5 T superconducting solenoid magnet. The transient strains and their abrupt changes were compared with the current, magnetic field and temperature signals collected during excitation and quench tests to indicate that the strain gauge measurements can detect the quench feature of the superconducting magnet. The proposed method is expected to be able to detect the quench of a superconducting coil independently or utilized together with other electrical methods. In addition, the axial quench propagation velocity of the solenoid is evaluated by the quench time lags among different localized strains. The propagation velocity is enhanced after repeated quench trainings.

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Section: Introductionmentioning

confidence: 99%

Strain-based quench detection for a solenoid superconducting magnet

Wang

Guan

2012

Supercond. Sci. Technol.

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“…This knowledge came too late to change the embedding process for the serial production to an active cooling of the winding pack during the heating process [7]. During the cold acceptance tests at CEA France and nominal current operation no special effects of load jumps could be observed [8] being in mind that the operational forces of W7-X will be 3 times higher.…”

Section: Embedding Proceduresmentioning

confidence: 99%

Experiences from design and production of Wendelstein 7-X magnets

Riße

Team

2009

Fusion Engineering and Design

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The Max-Planck-Institut für Plasmaphysik in Greifswald is building the stellarator fusion experiment Wendelstein 7-X (W7-X). The manufacturing of the W7-X superconducting magnet system, which consists of 50 non-planar and 20 planar coils, was finished in March 2008. The production was a technical challenge for the W7-X design crew as well for the manufacturer due to the complex 3 D shape of the non-planar coils and the stringent requirements for geometrical tolerances. The manufacturers had to solve several technical problems and to consider major design changes even at advanced stages of manufacture. Finally the coils are passing the acceptance tests at cryogenic temperatures at CEA Saclay with a very good performance. Results of the W7-X coil production will be given and critical production steps will be identified. Lessons will be taken from the experiences gained from design, manufacturing and test methods. The reasons for the considerable time delays will be explained.

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“…Therefore, monitoring simultaneous mechanical strain under extreme cryogenic multi eld conditions is both necessary and challenging. In such scenarios, strain is typically measured using low-temperature resistance strain gauges with temperatures ranging from room temperature (RT, ~293 K) to that of liquid helium (LHe, ~4.2 K) in several superconducting instruments [11][12][13][14][15][16][17][18][19][20]. However, cryogenics always causes a great drift thermal offset to the measurement, and the magnetic eld around the strain gauge can easily result in a magneto-resistance error [13].…”

Section: Introductionmentioning

confidence: 99%

Strain Measurement Method Based on External Symmetrical Compensation Bridge Composed of Strain Gauges with Four-Wire Configuration for a Large-Scale NbTi Superconducting Dipole Magnet Detector

Zhang,

Xin,

Gao

et al. 2023

J Low Temp Phys

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In this study, we present a strain measurement method based on an external symmetrical compensation bridge (ESCB) composed of strain gauges with a four-wire con guration. Unlike the traditional strain measurement methods, this method includes two features: rst, utilising the four-wire con guration to eliminate measurement errors that occur due to large space-varying thermal and eld imbalances of long signal wires during operation, and second, utilising two independent quarter-active sub-bridges with a four-wire con guration composed of ESCB to eliminate the errors that occur due to the large time-varying cryogenic temperature and magnetic eld. This method was used on a large-scale NbTi superconducting dipole magnet detector during the cooling, excitation, and quench tests. The strains measured using the ESCB were compared with those measured using a traditional half-active compensation bridge. The results indicated that the new method can accurately detect the strain features of a large-scale superconducting magnet. In addition, using the proposed method, spectrum analysis of strain measurements was implemented during excitation, quench onset, and post-quench. A larger amplitude at a higher frequency was clearly observed at the onset of a quench than that observed during excitation and post-quench. Thus, the dynamic strain characteristics of a superconducting magnet structure could be a candidate for predicting the quench.

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Data analysis of the strain gauges system of the W7-X superconducting coils

Cited by 12 publications

References 0 publications

Strain-based quench detection for a solenoid superconducting magnet

Strain-based quench detection for a solenoid superconducting magnet

Experiences from design and production of Wendelstein 7-X magnets

Strain Measurement Method Based on External Symmetrical Compensation Bridge Composed of Strain Gauges with Four-Wire Configuration for a Large-Scale NbTi Superconducting Dipole Magnet Detector

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