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

Luo, Linqing; Ferracin, P.; Stern, Jillian; Laan, D C van der; Wang, Xiaorong; Weiss, Jeremy; Wu, Yuxin

doi:10.1109/tasc.2022.3159507

Cited by 5 publications

(3 citation statements)

References 24 publications

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“…The experiment with the optic fiber demonstrated that the fiber can operate at 4.2 K. A successful impregnation technique will benefit future tests of the optic fiber toward identifying the hot spots along rebco cables [73] and ultimately the detection of normal transitions [74,75].…”

Section: Continue Developing Magnets Using Star® Wires Toward Higher ...mentioning

confidence: 99%

An initial magnet experiment using high-temperature superconducting STAR® wires

Wang

Bogdanof

Ferracin

et al. 2022

Supercond. Sci. Technol.

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A dipole magnet generating 20 T and beyond will require high-temperature superconductors such as Bi2Sr2CaCu2O8-x and REBa2Cu3O7-x (RE = rare earth, REBCO). Symmetric tape round (STAR®) wires based on REBCO tapes are emerging as a potential conductor for such a magnet, demonstrating a whole-conductor current density of 580 A mm-2 at 20 T, 4.2 K, and at a bend radius of 15 mm. There are, however, few magnet developments using STAR® wires. Here we report a subscale canted cosθ dipole magnet as an initial experiment for two purposes: to evaluate the conductor performance in a magnet conﬁguration and to start developing the magnet technology, leveraging the small bend radius aﬀorded by STAR® wires. The magnet was wound with two STAR® wires, electrically in parallel and without transposition. We tested the magnet at 77 and 4.2 K. The magnet reached a peak current of 8.9 kA, 78% of the short-sample prediction at 4.2 K, and a whole-conductor current density of 1500 A mm-2. The experiment demonstrated a minimum viable concept for dipole magnet applications using STAR® wires. The results also allowed us to identify further development needs for STAR® conductors and associated magnet technology to enable high-ﬁeld REBCO magnets.

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Section: Continue Developing Magnets Using Star® Wires Toward Higher ...mentioning

confidence: 99%

An initial magnet experiment using high-temperature superconducting STAR® wires

Wang

Bogdanof

Ferracin

et al. 2022

Supercond. Sci. Technol.

Self Cite

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“…The research on the bending performance of CORC cable verifies that it has good bending flexibility [19][20][21]. On the research of quenching detection, distributed optical fiber and ultrasonic detection method are used to monitor the state of CORC cable, which can ensure the safety of its operation [22,23]. The research of its axial tensile properties found that the spring structure of the CORC cable makes its tensile strain limit exceed that of HTS tape, and the tensile strain limit of the optimized cable exceeds 10 times of that of HTS tape [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Analysis on the transverse compression performance of the CORC cable

Shi¹,

Dai²,

Ma³

et al. 2022

Supercond. Sci. Technol.

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The conductor on round core (CORC) cable is considered as one of the best candidate cables for next generation fusion project due to its advantages of high current density, small cabling degradation and excellent magnetic ﬁeld performance. Nevertheless, the CORC cable will be aﬀected by huge transverse compression force during production and transportation, especially during operation in fusion project, which is the main reason that the current-carrying capacity of CORC cable will be irreversible degradation. There is little research on the transverse compression performance of CORC cables at present, and the inﬂuence rules of some cable parameters on its transverse compression performance are not clear yet. Therefore, in this paper, transverse compression tests are carried out on CORC cables of diﬀerent former sizes, materials and structure. The experimental results show that the larger the cable former size, the better its transverse compression performance. The transverse compression load limit of hollow tube former cable is larger than that of solid bar former cable. The performance of stainless steel bar former cable is similar to that of copper bar former cable. The limit value of transverse compression load of copper hollow tube former cable is larger than that of stainless steel hollow tube former cable. A 3D ﬁnite element model is also established to explain the internal reasons for the diﬀerences of current-carrying capacity decrease tendency of diﬀerent CORC cables. The research results can provide theoretical basis for the selection of former of CORC cable in the future. In addition, the inﬂuence of load block structure on the CORC cable’s transverse compression load limit is also studied in this paper. The results show that the arc block can signiﬁcantly increase the transverse compression load limit of CORC cable. The research results can provide a basis for the selection of the structure of support former when making cable in conduit conductor (CICC) and the structure of coil former when winding CORC coil magnet.

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“…In tokamaks, the large magnet inductances and fast ramp rates complicate protection with traditional sample voltage measurements. Several efforts have shifted toward temperature-based protection, including optical fibers [16][17][18][19] , active acoustic thermometry 20 , and co-wound superconducting wires optimized to act as a thermal switch [21][22][23] . Marchevsky et al 24 demonstrated quench detection in a slit ReBCO tape based on magnetic field changes associated with current redistribution, that was later demonstrated between tapes of a single CORC ® wire 25 and between cables of a CORC ® CICC 26 .…”

mentioning

confidence: 99%

Current distribution monitoring enables quench and damage detection in superconducting fusion magnets

Teyber

Weiss

Marchevsky

et al. 2022

Sci Rep

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Fusion magnets made from high temperature superconducting ReBCO CORC® cables are typically protected with quench detection systems that use voltage or temperature measurements to trigger current extraction processes. Although small coils with low inductances have been demonstrated, magnet protection remains a challenge and magnets are typically operated with little knowledge of the intrinsic performance parameters. We propose a protection framework based on current distribution monitoring in fusion cables with limited inter-cable current sharing. By employing inverse Biot-Savart techniques to distributed Hall probe arrays around CORC® Cable-In-Conduit-Conductor (CICC) terminations, individual cable currents are recreated and used to extract the parameters of a predictive model. These parameters are shown to be of value for detecting conductor damage and defining safe magnet operating limits. The trained model is then used to predict cable current distributions in real-time, and departures between predictions and inverse Biot-Savart recreated current distributions are used to generate quench triggers. The methodology shows promise for quality control, operational planning and real-time quench detection in bundled CORC® cables for compact fusion reactors.

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

Cited by 5 publications

References 24 publications

An initial magnet experiment using high-temperature superconducting STAR® wires

An initial magnet experiment using high-temperature superconducting STAR® wires

Analysis on the transverse compression performance of the CORC cable

Current distribution monitoring enables quench and damage detection in superconducting fusion magnets

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