A numerical method for spatially-distributed transient simulation to replicate nonlinear ‘defect-irrelevant’ behaviors of no-insulation HTS coil

Kim, Geonyoung; Musso, Andrea; Bang, Jeseok; Lee, Jung Tae; Im, Chaemin; Choi, Kyeongdal; Kim, Jaemin; Breschi, Marco; Han, Ki Jin; Hahn, Seungyong

doi:10.1088/1361-6668/ac211f

Cited by 19 publications

(7 citation statements)

References 49 publications

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“…For instance, quench detection, magnet diagnostics, and instrumentation techniques [2][3][4][5][6][7][8][9][10][11][12][13][14] have been considerably studied to investigate NI REBCO magnet quench. As a result, various quench simulation models [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] have been proposed, and it has been demonstrated that they are practicable in replicating quench voltage and the corresponding current distribution to some degree. However, these simulations still struggle to reproduce module coil voltages during quench in high magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

An experimental study to investigate magnetic field and winding force-dependent contact resistance of NI REBCO coil

Bang,

Bradford,

Lee

et al. 2024

Supercond. Sci. Technol.

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This paper reports the magnetic field and winding force-dependent contact resistance, also known as characteristic resistance, of no-insulation (NI) REBCO coil. Three NI coils were wound with different winding forces (<1 kgf, 3 kgf, and 5 kgf) using the same REBCO-coated conductor, and they were tested at 4.2 K in a background field of 0, 5, 10, and 14 T. The contact resistance of each coil is measured at each field. As a result of the measurements, we draw two conclusions. First, a quadratic function for magnetic field intensity reasonably reproduces the measurement results of each NI test coil's magnetic field-dependent contact resistance, where the practical fit function's coefficients are determined depending on the winding force. Second, the contact resistance of each coil is partially inconsistent with the magnetoresistance of the electroplated material, i.e., copper, of the REBCO-coated conductor. This paper will present the measurement results in detail, discuss them with Kohler's rule, and formulate the contact resistance using winding force and magnetic field terms.

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Section: Introductionmentioning

confidence: 99%

An experimental study to investigate magnetic field and winding force-dependent contact resistance of NI REBCO coil

Bang,

Bradford,

Lee

et al. 2024

Supercond. Sci. Technol.

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“…The no-insulation (NI) winding technique [24] provides HTS coils with better thermal stability [25,26], higher current density [27,28], defect-irrelevance properties [29,30] and better mechanical integrity [31][32][33][34][35]. In recent years, the NI winding technique has facilitated quite a few breakthroughs in HTS magnet technology [28,36].…”

Section: Introductionmentioning

confidence: 99%

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

Zhong,

Wu,

et al. 2024

Supercond. Sci. Technol.

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The no-insulation (NI) winding technique is promising to be applied in the persistent-current mode (PCM) operation of high-temperature superconducting (HTS) coils to provide those advantages. To apply the NI PCM coil, its demagnetization behaviour (i.e., decay of persistent DC current) by external AC field, which occurs in maglev trains, electric machines, and other dynamic magnet systems, is essential to be understood. For this purpose, a 3D FEM model, capturing the full electromagnetic properties of NI HTS coils, is established. This work has studied three kinds of AC fields, observing the impact of turn-to-turn contact resistivity on demagnetization rates, which is attributed to current distribution modulations. Under transverse AC field, the lower contact resistivity attracts more transport current to flow in the radial pathway to bypass the ‘dynamic resistance’ generated in the superconductor, leading to slower demagnetization. Under axial AC field, the demagnetization rate exhibits a non-monotonic relation with the contact resistivity: (1) the initial decrease of contact resistivity leads to concentration of induced AC current on the outer turns, which accelerates the demagnetization; (2) the further decrease of contact resistivity makes the current smartly redistribute to avoid to flow through the loss-concentrated outer turns, thus slowing down the demagnetization. Under the rotating DC field, a hybrid of the transverse and axial fields, the impact of contact resistivity on the demagnetization rate exhibits combined characteristics of the transverse and axial components. Besides, quantitative prediction on the demagnetization rate of NI PCM coil under external AC field is instructive for practical designs and operations, which is tried by this 3D FEM model, and a comparison with experimental result is conducted.

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“…Charge-discharge cycles are performed at different ramp rates, up to 5 A/s, as well as fast discharge tests. Compared to the results reported in [13], where the same coil was operated in a liquid nitrogen bath, in this work the tests are carried out with conduction cooling, at temperatures between 4.7 K and 80 K. The coil electromagnetic behavior is assessed by measuring the magnetic field produced in its bore and the voltage signal acquired at the coil ends. The measurements are also used to retrieve, by means of a simplified lumped parameter circuit, some useful effective parameters, such as the longitudinal and radial resistances, from which the fraction of operating current flowing radially throughout the winding is estimated.…”

Section: Introductionmentioning

confidence: 99%

Analysis of a No-Insulation HTS Pancake Coil Including Multiple Resistive Joints

Musso

Bang

Bong

et al. 2022

IEEE Trans. Appl. Supercond.

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One of the technical issues in the application of High Temperature Superconducting (HTS) tapes to magnet technology is the need to wind long tape sections with uniform electric properties along the length. It has been reported that a No-Insulation (NI) coil can properly work even in the presence of defective super-conductive regions, with a minimal drop of performance as com-pared to its "defect-free" counterpart. This could open up the possibility of manufacturing coils by jointing together several tape segments of limited length, lowering the conductor cost. In this work, a single pancake NI HTS coil is wound using several tape segments cut from the same lot, jointed together. The electrical resistance of each joint is set independently, realizing either high or low resistance joints. Thus, the coil is designed to include multiple defective sections at specific locations. The coil is refrigerated by conduction-cooling, and tested at different temperatures and charging rates. The coil instrumentation allows measuring the voltage over the whole winding, as well as the magnetic field in the central bore. The measurements are used to study the defect-irrelevant behavior of the coil. A simple equivalent lumped parameter circuit is applied to derive the coil effective parameters and analyze its electromagnetic behaviour.

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A numerical method for spatially-distributed transient simulation to replicate nonlinear ‘defect-irrelevant’ behaviors of no-insulation HTS coil

Cited by 19 publications

References 49 publications

An experimental study to investigate magnetic field and winding force-dependent contact resistance of NI REBCO coil

An experimental study to investigate magnetic field and winding force-dependent contact resistance of NI REBCO coil

Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation

Analysis of a No-Insulation HTS Pancake Coil Including Multiple Resistive Joints

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