Preliminary Tests of Pancakes From a 12 T REBCO Insulated Solenoid Magnet

Vialle, Julien; Badel, Arnaud; Tixador, Pascal; Cicéron, Jérémie; Forest, Frederick; Pasquet, Raphael

doi:10.1109/tasc.2021.3057837

Cited by 8 publications

(5 citation statements)

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“…Of course, the drawback of this solution is that identifying the defective DP is impossible if the protection triggers during a current transient. Moreover, an excellent energy efficiency, 98.6 %, was obtained over the full chargedischarge cycle of this assembly (the discharge time constant was set to 6 s, slower than the 1 s target in the final configuration [2]). The losses are AC losses and connection losses.…”

Section: A Assembly Characteristics and Test Resultsmentioning

confidence: 99%

“…For the final assembly the protection system presented in [2] will therefore be multiplied by up to 21 (Fig. 5).…”

Section: Protection Of Dps In Assembliesmentioning

confidence: 99%

“…A detection concept using pickup coils to compensate the inductive component of the signal and some of the noise during current ramps, as well as numerical low pass filtering was introduced [4]. The sensitivity of the quench detection system is in the 100 µV range, which made it possible to test a first full-scale prototype of DP at 4.2 K up to its limiting critical current (972 A with 0.18 A/s) without any degradation [2]. The test of this DP prototype under background field is presented in part II, validating the mechanical design.…”

Section: Introductionmentioning

confidence: 99%

“…This project started in 2015 and all conductor lengths were procured at that time. Considering the uncertainty on tape performances from this period in low temperature/high field and the low critical current margin of the design (14 % see [2]), it was decided to test all DPs in liquid helium to the rated current before assembly. The results of the evaluation campaign for the 21 DPs are presented part III.…”

Section: Introductionmentioning

confidence: 99%

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12 T Insulated REBCO Magnet Used as 1 MJ SMES: Protection Strategies and Preliminary Assembly Tests

Vialle

Badel

Tixador

2022

IEEE Trans. Appl. Supercond.

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In the framework of the BOSSE project, a 12 T insulated REBCO solenoid is being manufactured. This magnet will be used as a SMES with the objective to reach 1 MJ and a specific energy of 20 kJ/kg for the winding. To manufacture this solenoid and reach such performances, 21 insulated REBCO Double Pancakes (DPs) will be assembled and cooled in a liquid helium bath at 4.2 K. To validate the solenoid's electromagnetic design, a prototype DP tested in self-field up to its critical current (972 A), thanks to a sensitive protection system, was presented in a previous work. Here we present the background magnetic field test of this prototype DP which allowed to validate the coil's mechanical design. In order to validate the electromagnetic performances of the 21 DPs, each of them is tested in liquid helium up to its rated current. The performances of the 17 DPs already tested and validated will also be presented. Finally, we will present the tests and results of 2 preliminary assemblies of 3 and 5 DPs. These assemblies were tested with two different protection philosophies. The results of these tests show that an individual protection of each DP is to be preferred in order to obtain a better sensitivity on the protection signal.

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Section: A Assembly Characteristics and Test Resultsmentioning

confidence: 99%

“…For the final assembly the protection system presented in [2] will therefore be multiplied by up to 21 (Fig. 5).…”

Section: Protection Of Dps In Assembliesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

12 T Insulated REBCO Magnet Used as 1 MJ SMES: Protection Strategies and Preliminary Assembly Tests

Vialle

Badel

Tixador

2022

IEEE Trans. Appl. Supercond.

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“…The detection sensitivity increases if we adapt the threshold dynamically during the ramp based on the expected drift, which can be obtained from simulation results beforehand. This is the solution we consider for future large scale REBCO coils, and that we already used for testing numerous double pancakes in the BOSSE project [10,19].…”

Section: Conclusion and Prospectmentioning

confidence: 99%

Transient voltages and energy balance in REBCO insulated magnet: experimental and numerical studies

Vialle

Badel

Rozier

et al. 2021

Supercond. Sci. Technol.

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Different means are investigated today to protect a REBCO coil against local thermal runaway, what is commonly called a "Quench". Metal Insulated Coil or No-Insulated coil have been successfully introduced. However, these protections method may show other issues and are limited in terms of dynamics, making them impractical for fast applications. We successfully tested early detection of dissipative voltage followed by current dumping as a method to protect REBCO insulated test coils, even with engineering current density in the kA/mm2 range. Pick up coils can be used to compensate inductive coil voltage. In previous works we highlighted the presence of transient voltage due to the hysteretic current distribution in REBCO tape width, which can complicate the detection. We then developed a numerical electromagnetic model that reproduce the transient behaviour of REBCO coils. Here we study a small REBCO coil instrumented with three different pick-up coils, including a co-wound pick-up whose coupling is close to perfect. The post processing and analysis of the simulation results makes it possible to identify in the transient coil voltage the contribution due to transient losses and coil inductance variation. The resulting evaluation of the REBCO coil inductance and its variations is validated by analysis of the pick-up coil signals. From a practical point of view, this work shows the possibility to have very sensitive early detection of thermal runaway if the threshold is adjusted based on the expected coil compensated voltage drift. The interest of using isolated high-strength co-wound reinforcement tape as pick-up coil is also highlighted.

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