Numerical Impact of Using Different $E$ –$J$  Relationships for 3-D Simulations of AC Losses in MgB2Superconducting Wires

Escamez, Guillaume; Sirois, Frédéric; Badel, Arnaud; Meunier, G.; Ramdane, Brahim; Tixador, Pascal

doi:10.1109/tmag.2015.2480960

Cited by 6 publications

(3 citation statements)

References 16 publications

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“…This is a side effect of using a power law model, in which the dissipative voltage is never truly zero. The use of an alternative power law, such as the one proposed in [59], would lead to a strictly 0 value.…”

Section: Small-scale Insulated Coilmentioning

confidence: 99%

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Rozier

Badel

Ramdane

et al. 2019

Supercond. Sci. Technol.

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High-temperature superconducting materials have remarkable current-carrying capabilities, even when operated under high magnetic fields. Since long rare earth-barium-copper oxide (REBCO)-coated conductors are now available (thanks to improvements in the fabrication process) this material has become an attractive option for high field magnet applications. However, such extreme operating conditions require an efficient quench protection system to prevent the coil from developing damaging hot spots, which greatly depends on the winding used. We focus here on the protection of insulated HTS coils against thermal runaways that can locally destroy the magnet. We developed a transient two-dimensional (2D) axisymmetric model using a volume integral formulation based on generalization of the partial element equivalent circuit method to compute the local current density distribution inside REBCO-insulated coils and account for local performance variations. Indeed, the most interesting property of integral methods is the requirement that only active regions are meshed, which leads to a significant reduction in the size of the problem. The formulation is introduced for general 3D cases and its adaptation to 2D axisymmetric problems is detailed. The formulation has been validated thanks to a bulk magnetization benchmark, the results of which (obtained with the finite element method) were compared with our integral formulation solution. The model has also been compared with experimental data obtained on a double pancake coil. The objective is to study the effects of magnetization on the transient voltage due to dynamic current distribution when ramping up the magnet so as to be able to determine some key parameters associated with coil protection. Such an approach is developed on a small-scale test case and the transient behaviours observed are discussed.

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Section: Small-scale Insulated Coilmentioning

confidence: 99%

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Rozier

Badel

Ramdane

et al. 2019

Supercond. Sci. Technol.

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“…We refer the reader to research work dedicated to electromagnetic formulations applied to superconducting problems for a critical assessment of the H-formulation versusother formulations such as -f T or --f y H [24,25], which provide stronger ways to ensure current conservation in conducting regions. Note however that the H-formulation used in Daryl-Maxwell has been validated and benchmarked against other formulations in [26].…”

Section: Description Of the Modelmentioning

confidence: 99%

Experimental characterization of the constitutive materials of MgB₂multi-filamentary wires for the development of 3D numerical models

Escamez¹,

Sirois²,

Tousignant³

et al. 2017

Supercond. Sci. Technol.

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Today MgB2 superconducting wires can be manufactured in long lengths at low cost, which makes this material a good candidate for large scale applications. However, because of its relatively low critical temperature (less than 40 K), it is necessary to operate MgB2 devices in a liquid or gaseous helium environment. In this context, losses in the cryogenic environment must be rigorously minimized, otherwise the use of a superconductor is not worthy. An accurate estimation of the losses at the design stage is therefore mandatory in order to allow determining the device architecture that minimizes the losses. In this paper, we present a complete a 3D finite element model of a 36-filament MgB2 wire based on the architecture of the Italian manufacturer Colombus. In order for the model to be as accurate as possible, we made a substantial effort to characterize all constitutive materials of the wire, namely the E–J characteristics of the MgB2 filaments and the electric and magnetic properties (B−H curves) of nickel and monel, which are the two major non-superconducting components of the wire. All properties were characterized as a function of temperature and magnetic field. Limitations of the characterization and of the model are discussed, in particular the difficulty to extract the maximum relative permeability of nickel and monel from the experimental data, as well as the lack of a thin conductive layer model in the 3D finite element method, which prevents us from taking into account the resistive barriers around the MgB2 filaments in the matrix. Two examples of numerical simulations are provided to illustrate the capabilities of the model in its current state.

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“…Among the models used for investigating the electromagnetic behavior of superconductors, the finite-element method (FEM) based on the H formulation of Maxwell's equations combined with the power-law model of the superconductor is by far the most widely adopted approach, used by tens of research group around the world [1]. The reason of such popularity mainly resides in the easiness of implementation in the FEM program Comsol Multiphysics [2], [3], although implementations in other commercial software packages like FlexPDE [4] and Matlab [5], open-source environments like GetDP [6], and home-made FEM codes like Daryl Maxwell [7] also exist.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Modeling of Superconductors With Commercial Software: Possibilities With Two Vector Potential-Based Formulations

Grilli

Pardo

Morandi

et al. 2021

IEEE Trans. Appl. Supercond.

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In recent years, the H formulation of Maxwell's equation has become the de facto standard for simulating the time-dependent electromagnetic behavior of superconducting applications with commercial software. However, there are cases where other formulations are desirable, for example for modeling superconducting turns in electrical machines or situations where the superconductor is better described by the critical state than by a power-law resistivity. In order to accurately and efficiently handle those situations, here we consider two published approaches based on the magnetic vector potential: the T -A formulation of Maxwell's equations (with power-law resistivity) and Campbell's implementation of the critical state model. In this contribution, we extend the T -A formulation to thick conductors so that large coils with different coupling scenarios between the turns can be considered. We also revise Campbell's model and discuss it in terms of its ability to calculate AC losses: in particular, we investigate the dependence of the calculated AC losses on the frequency of the AC excitation and the possibility of using quick one-step (instead of full cycle) simulations to calculate the AC losses.

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Numerical Impact of Using Different $E$ –$J$ Relationships for 3-D Simulations of AC Losses in MgB2Superconducting Wires

Cited by 6 publications

References 16 publications

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Experimental characterization of the constitutive materials of MgB₂multi-filamentary wires for the development of 3D numerical models

Electromagnetic Modeling of Superconductors With Commercial Software: Possibilities With Two Vector Potential-Based Formulations

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Numerical Impact of Using Different $E$ –$J$ Relationships for 3-D Simulations of AC Losses in MgB2Superconducting Wires

Cited by 6 publications

References 16 publications

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Calculation of the local current density in high-temperature superconducting insulated rare earth–barium–copper oxide coils using a volume integral formulation and its contribution to coil protection

Experimental characterization of the constitutive materials of MgB2multi-filamentary wires for the development of 3D numerical models

Electromagnetic Modeling of Superconductors With Commercial Software: Possibilities With Two Vector Potential-Based Formulations

Contact Info

Product

Resources

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Experimental characterization of the constitutive materials of MgB₂multi-filamentary wires for the development of 3D numerical models