<i>n</i>-Values of commercial YBCO tapes before and after irradiation by fast neutrons

Chudý, Michal; Zhong, Zhaoyang; Eisterer, M.; Coombs, Tim

doi:10.1088/0953-2048/28/3/035008

Cited by 29 publications

(27 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the lumped-parameters and FEM models, the inhomogeneity and anisotropy of the n index are not taken into account. A constant value

ranging broadly from 20 to 45 is used instead [ 31 , 32 ]. For

, the inhomogeneity is often omitted.…”

Section: Rebco Materialsmentioning

confidence: 99%

“…The power-law formulated in terms of the voltage V along the superconductor and its DC current I takes the following form [ 31 ],

where

, with

the critical electric field ranging from 0.1 to 10 μV/cm depending on the size of the system under characterization.

is the distance between the voltage taps along the tape.…”

Section: Modeling Based On Lumped Parametersmentioning

confidence: 99%

See 1 more Smart Citation

Essential Material Knowledge and Recent Model Developments for REBCO-Coated Conductors in Electric Power Systems

2021

View full text Add to dashboard Cite

The manufacturing of commercial REBCO tapes, REBCO referring to Rare-earth barium copper oxide, has matured enough to lead to a variety of applications ranging from scientific instruments to electric power systems. In particular, its large current density with a high n index and low hysteresis losses make it a strong candidate for specific applications relying on the dependence of its resistance on current. Despite its advantages, there are still issues that remain to be addressed, such as the scarcity of experimental data for the basic characteristics of the superconductor over a wide range of temperature and applied magnetic field, the homogeneity of these characteristics along the conductor length, as well as the anisotropy of the critical current and n index with respect to the direction of the applied magnetic field. To better utilize the technology, it is therefore sensible to understand the relevancy of these issues so that one could simulate as accurately as possible the physics of the superconductor, at least the dynamics that may impact the correct operation of the superconducting device. There are different levels of modelling to achieve such a goal that can either focus on the performance of the superconductor itself, or on the whole device. The present work addresses some of the latest developments in the modelling of commercial REBCO tapes in power systems with a particular focus on the thermoelectric behavior of superconducting devices connected to external circuits. Two very different approaches corresponding to two different scales in the modelling of superconducting devices are presented: (1) analysis using equivalent models and lumped parameters to study the thermoelectric response of superconducting devices as a whole, (2) Finite Element Analysis (FEA) to compute distributed fields such as current density, magnetic flux density and local losses in tapes. In this context, this paper reviews both approaches and gives a broad variety of examples to show their practical applications in electric power systems. Firstly, they show the relevance of the technology in power systems engineering. Secondly, they allow inferring the necessary level of model details to optimize the operation of superconducting power devices in power grids. This level of details relies completely on the knowledge of some basic measurable properties of superconducting tapes (critical current and n index) and their cooling conditions.

show abstract

“…In the lumped-parameters and FEM models, the inhomogeneity and anisotropy of the n index are not taken into account. A constant value

ranging broadly from 20 to 45 is used instead [ 31 , 32 ]. For

, the inhomogeneity is often omitted.…”

Section: Rebco Materialsmentioning

confidence: 99%

“…The power-law formulated in terms of the voltage V along the superconductor and its DC current I takes the following form [ 31 ],

where

, with

the critical electric field ranging from 0.1 to 10 μV/cm depending on the size of the system under characterization.

is the distance between the voltage taps along the tape.…”

Section: Modeling Based On Lumped Parametersmentioning

confidence: 99%

Essential Material Knowledge and Recent Model Developments for REBCO-Coated Conductors in Electric Power Systems

2021

View full text Add to dashboard Cite

show abstract

“…These values were chosen to reproduce the trend of the n-value as a function of magnetic flux density and temperature [16]- [18]. b) Thermal model: The thermal model which is coupled to the electromagnetic model through the dissipating term Q = σ ∂A/∂t 2 includes temperature-dependent material properties.…”

Section: Modeling Of the Problemmentioning

confidence: 99%

Distribution of Current Density, Temperature, and Mechanical Deformation in YBCO Bulks Under Field-Cooling Magnetization

Trillaud

Berger

Douine

et al. 2018

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Abstract-Most of the latest models of HTS bulk magnetization take into account the thermal and electromagnetic coupling, but, they still lack the implementation of the mechanical deformation under strong magnetic fields. The following work tries to fill up partly the gap by proposing a model of the dependence of the electrical conductivity upon mechanical deformation during Field-Cooling magnetization. This dependence is carried out by the critical current density as a function of induced thermal and mechanical strain in the bulk. As a first approximation and bearing in mind the obvious discrepancies, a simple model inferred from HTS thin films and generic knowledge on ceramics is proposed. This first approach allows drawing some generalities on the expected thermal, magnetic and mechanical response of disk-shaped YBCO pellets during magnetization. The utter goal is to assess design parameters to insert those pellets in electrical rotatory machines.

show abstract

“…For NbTi the index N is typically above 40 at background fields below 7 tesla. In HTS materials, especially when operated at higher temperatures, the relative pinning strength is comparatively lower as compared to the thermal activation, which leads to flux creep, but extrinsic limitations on N may be just as important ([21] and references there), especially at low temperatures. The N -value in HTS conductor is often below 30 and in some cases degrades to less than 20 at a relatively low background field of 0.5 tesla.…”

Section: Conductor Requirements Challenges and Opportunitiesmentioning

confidence: 99%

Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

Parizh

Lvovsky

Sumption

2016

Supercond. Sci. Technol.

126

107

View full text Add to dashboard Cite

Magnetic Resonance Imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. In this paper, we analyze conductor requirements for commercial MRI magnets beyond traditional NbTi conductors, while avoiding links to a particular magnet configuration or design decisions. Potential conductor candidates include MgB2, ReBCO and BSCCO options. The analysis shows that no MRI-ready non-NbTi conductor is commercially available at the moment. For some conductors, MRI specifications will be difficult to achieve in principle. For others, cost is a key barrier. In some cases, the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed. The key needs include the development of, or significant improvements in: (a) conductors specifically designed for MRI applications, with form-fit-and-function readily integratable into the present MRI magnet technology with minimum modifications. Preferably, similar conductors should be available from multiple vendors; (b) conductors with improved quench characteristics, i.e. the ability to carry significant current without damage while in the resistive state; (c) insulation which is compatible with manufacturing and refrigeration technologies; (d) dramatic increases in production and long-length quality control, including large-volume conductor manufacturing technology. In-situ MgB2 is, perhaps, the closest to meeting commercial and technical requirements to become suitable for commercial MRI. Conductor technology is an important, but not the only, issue in introduction of HTS / MgB2 conductor into commercial MRI magnets. These new conductors, even when they meet the above requirements, will likely require numerous modifications and developments in the associated magnet technology.

show abstract

n-Values of commercial YBCO tapes before and after irradiation by fast neutrons

Cited by 29 publications

References 33 publications

Essential Material Knowledge and Recent Model Developments for REBCO-Coated Conductors in Electric Power Systems

Essential Material Knowledge and Recent Model Developments for REBCO-Coated Conductors in Electric Power Systems

Distribution of Current Density, Temperature, and Mechanical Deformation in YBCO Bulks Under Field-Cooling Magnetization

Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

Contact Info

Product

Resources

About