SMART conductor on round core (CORC<sup>®</sup>) wire via integrated optical fibers

Scurti, Federico; Weiss, Jeremy; Laan, D C van der; Schwartz, J.

doi:10.1088/1361-6668/abdc7f

Cited by 27 publications

(23 citation statements)

References 44 publications

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“…Indeed, Rayleigh-scattering based fibers were used to detect the temperature change with a high spatial resolution in the millimeter range [46]. Fibers have been also integrated into a REBCO conductor architecture and demonstrated strain sensing capabilities as well as thermal perturbation detection and localization with higher spatial resolution than voltage taps [15,50,51]. More R&D development will be necessary for employment of Rayleigh distributed sensors in superconducting magnets.…”

Section: Fiberoptic Diagnosticsmentioning

confidence: 99%

Advancing Superconducting Magnet Diagnostics for Future Colliders

Marchevsky¹,

Teyber²,

Lee³

et al. 2022

Preprint

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Future colliders will operate at increasingly high magnetic fields pushing limits of electromagnetic and mechanical stress on the conductor [1]. Understanding factors affecting superconducting (SC) magnet performance in challenging conditions of high mechanical stress and cryogenic temperatures is only possible with the use of advanced magnet diagnostics. Diagnostics provide a unique observation window into mechanical and electromagnetic processes associated with magnet operation, and give essential feedback to magnet design, simulations and material research activities. Development of novel diagnostic capabilities is therefore an integral part of next-generation magnet development. In this paper, we summarize diagnostics development needs from a prospective of the US Magnet Development Program (MDP), and define main research directions that could shape this field in the near future.

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Section: Fiberoptic Diagnosticsmentioning

confidence: 99%

Advancing Superconducting Magnet Diagnostics for Future Colliders

Marchevsky¹,

Teyber²,

Lee³

et al. 2022

Preprint

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“…A reference reading is recorded first when no strain and uniform temperature is applied to the FUT. By correlating the readings to the reference, one can obtain a frequency shift which linearly indicates the change of strain and temperature on the FUT [16][20] [21]:…”

Section: Optical Frequency Domain Reflectometrymentioning

confidence: 99%

“…The same technology was demonstrated to have a similar sensitivity at 77 K and room temperature in a subsequent study [14]. More recently, the OFDR technology was tested with an optical fiber embedded inside a REBCO CORC ® cable for quench detection [15] [16].…”

Section: Introductionmentioning

confidence: 95%

“…Although the fiber optic sensing shows a mixed performance for quench detection due to a stringent temporal resolution and high sensitivity to local heating [15][16][17], the distributed sensing capability of fiber optic remains attractive to address our need to identify the locations of initial flux-flow voltages in multi-tape REBCO cables and magnets.…”

Section: Introductionmentioning

confidence: 99%

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Distributed Fiber Optic Sensing to Identify Locations of Resistive Transitions in REBCO Conductors and Magnets

Luo

Ferracin

Stern

et al. 2022

IEEE Trans. Appl. Supercond.

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High-temperature superconductors such as REBa2Cu3O7-x (REBCO, RE = rare earth) can generate strong magnetic fields that are promising for applications in particle accelerators and compact fusion reactors. Traditionally, voltage taps are installed in superconducting magnets to measure the voltage signals due to resistive transitions. The voltage-tap-based diagnostics is important for the development of magnet technology as it can help pinpoint the locations in the magnet windings that limit the magnet performance. The architecture of the multi-tape REBCO cable such as CORC ® wires, however, makes it difficult to apply the voltage-tapbased diagnostics to identify the locations of resistive transitions. Distributed fiber optic sensing (DFOS) has the potential to address this issue. In this paper, we report the measurements of thermal strain along a CORC ® wire based on optical frequency domain reflectometry with a maximum spatial resolution of 0.65 mm and a temporal resolution of 10 Hz. The optical fiber is co-wound with the CORC ® wire that is epoxy impregnated. During the test, current was increased until a resistive transition occurred in the conductor. The spectrum shift of the reflected light along the fiber was recorded.The results suggested that with proper thermal isolation from the cryogen, DFOS can be used to identify the locations of resistive transitions in CORC ® wires and magnets. The results will allow a better understanding of the causes of resistive transitions in REBCO conductors and magnets, which will help improve the REBCO magnet technology.

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“…The change in spectral shifts of between −1.5 and 1.5 GHz between the terminations are thus likely caused by a combination of changes in local strain state induced by the Lorenz force on the CORC ® wire during energization and local temperature increases. A more detailed study of the origin of spectral shift signal in CORC ® cables at different conditions can be found in [34]. The much larger spectral shift at the locations of the current adapters is clearly caused by local Joule heating.…”

Section: Detection Of Ohmic Heating In Corc ® Terminations With Optic...mentioning

confidence: 99%

CORC^® wires containing integrated optical fibers for temperature and strain monitoring and voltage wires for reliable quench detection

Laan

Weiss

Scurti

et al. 2020

Supercond. Sci. Technol.

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Safe operation of large superconducting magnets wound from high-temperature superconductors (HTS) requires reliable detection of the onset of a quench. A novel method to integrate optical fibers and voltage wires within the core of multi-tape HTS CORC ® wires has been developed that allows real time monitoring of local changes in strain, temperature and of the superconducting state of the magnet windings. The ability to detect highly localized changes in temperature with Rayleigh scattering in the embedded optical fibers provides invaluable information about local heating at hot spots from which a quench may originate. Integrated voltage contacts allow accurate voltage measurements in long CORC ® wires without being affected by high current ramp rates or electromagnetic interference. They also allow detection of inductively driven redistribution of current between tapes in CORC ® wires that may occur at high current ramp rates. Continuous monitoring of temperature and voltage was used to detect the formation of local hot spots induced by a heater or by operating the CORC ® wire above its critical current. The results show that, within the boundary conditions of the experiment and the method by which the optical fibers were integrated into the CORC ® wire in this study, the speed and resolution with which hot spots can be detected with optical fibers lagged that of the integrated voltage wires. This study also shows that integrated voltage wires reliably detected the formation of a local hot spot in a 5.1 meter long coiled CORC ® wire, down to a hot spot size covering 0.1% of the conductor length and at current ramp rates as high as 2000 A s −1 . Voltage measurements thus remain an effective option for quench detection in magnets wound with HTS conductors for which current sharing between tapes allows for operation within the flux flow regime.

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SMART conductor on round core (CORC^®) wire via integrated optical fibers

Cited by 27 publications

References 44 publications

Advancing Superconducting Magnet Diagnostics for Future Colliders

Advancing Superconducting Magnet Diagnostics for Future Colliders

Distributed Fiber Optic Sensing to Identify Locations of Resistive Transitions in REBCO Conductors and Magnets

CORC^® wires containing integrated optical fibers for temperature and strain monitoring and voltage wires for reliable quench detection

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SMART conductor on round core (CORC®) wire via integrated optical fibers

Cited by 27 publications

References 44 publications

Advancing Superconducting Magnet Diagnostics for Future Colliders

Advancing Superconducting Magnet Diagnostics for Future Colliders

Distributed Fiber Optic Sensing to Identify Locations of Resistive Transitions in REBCO Conductors and Magnets

CORC® wires containing integrated optical fibers for temperature and strain monitoring and voltage wires for reliable quench detection

Contact Info

Product

Resources

About

SMART conductor on round core (CORC^®) wire via integrated optical fibers

CORC^® wires containing integrated optical fibers for temperature and strain monitoring and voltage wires for reliable quench detection