Modeling and Comparison of In-Field Critical Current Density Anisotropy in High-Temperature Superconducting (HTS) Coated Conductors

Di, Honggui; Ainslie, Mark; Raine, Mark J.; Hampshire, D.P.; Zeng, Jin

doi:10.1109/tasc.2016.2521585

Cited by 33 publications

(34 citation statements)

References 23 publications

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“…Classically, in LTS applications, the electric field criterion is given as E 0 = 10 µV/m, which is the value also used in this paper. It must be noted, however, that in some other publications [41,42], reporting HTS experiments, a criterion of 100 µV/m is used. To determine the critical current the electric field in the coil is plotted against the current in a so-called EI-curve, which is defined here as the averaged electric field against the current in the coil, as opposed to en EJ-relation that describes the local behavior.…”

Section: Sc Transition and Critical Currentmentioning

confidence: 99%

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Nugteren

Kirby

Bajas

et al. 2018

Supercond. Sci. Technol.

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This paper describes the standalone magnet cold testing of the high temperature superconducting magnet Feather-M2.1-2. This magnet was constructed within the European funded FP7-EUCARD2 collaboration to test Roebel type HTS cable, and is one of the first high temperature superconducting dipole magnets in the world. The magnet was operated in forced flow helium gas with temperatures ranging between 5 to 85 K. During the tests a magnetic dipole field of 3.1 T was reached inside the aperture at a current of 6.5 kA and a temperature of 5.7 K. These values are in agreement with the self-field critical current of the used SuperOx cable assembled with Sunam tapes (lowperformance batch), thereby confirming that no degradation occurred during winding, impregnation, assembly and cool-down of the magnet. The magnet was quenched many tens of times by ramping over the critical current and no degradation nor training was evident. During the tests the voltage over the coil was monitored in the micro-volt range. An inductive cancellation wire was used to remove the inductive component, thereby significantly reducing noise levels. Close to the quench current, drift was detected both in temperature and voltage over the coil. This drifting happens in a time scale of minutes and is a clear indication that the magnet has reached its limit. All quenches happened approximately at the same average electric field and thus none of the quenches occurred unexpectedly.

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Section: Sc Transition and Critical Currentmentioning

confidence: 99%

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Nugteren

Kirby

Bajas

et al. 2018

Supercond. Sci. Technol.

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“…For both critical current and AC loss simulations, we used J c (B, θ) values deduced from the measured I c (B, θ) shown in figure 2, by generating a three column look-up table [B radial , B axial , J c (B radial , B axial )], where B radial and B axial are the radial and axial components of the magnetic field, and using the direct interpolation method [32]. If the field angle is α, B radial =Bcos(α)=B r and B axial =Bsin(α)=B z as shown in figure 1. The B radial and B axial components of the other field angles shown in figure 7 can be calculated in a similar way, resulting in the set of components shown in table 1 for the four different assemblies.…”

Section: Methodsmentioning

confidence: 99%

Exploiting asymmetric wire critical current for the reduction of AC loss in HTS coil windings

et al. 2019

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Critical current and AC loss in coil windings are two important factors for various HTS applications. Many coated conductors exhibit asymmetry in the variation of the critical current with magnetic field angle. This asymmetry results in different coil critical current values depending on the orientation of the conductors in the coil windings. We report critical current and AC loss results at 77 K and 65 K for three hybrid coil assemblies which have a common central winding and different arrangements of the end windings. We found a difference greater than 13% in both the critical current and the AC loss results for the different arrangements. The results imply that if we wind coil assemblies smartly even using the same materials and the same design, we can not only improve critical current but also reduce AC loss significantly.

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“…2 A test circular, epoxy-impregnated HTS coil used for DC characterisation measured J c (B, θ) simply and directly as input data for the model. This type of direct interpolation can significantly improve the computational speed and convergence of the model, even when the real tape thickness is modelled, and avoids complicated data fitting while improving accuracy [22]. Another example of how to extract a J c (B, θ) relationship from experimental data can be found in [23].…”

Section: Modelling Framework For Hts Coilsmentioning

confidence: 99%

“…For the numerical simulation, the 2D axisymmetric model above is used, and the J c (B, θ) dependence of a short sample taken from the same spool of tape provided in [22] (sample SP1 in this reference) is input using the direct interpolation described above. The inner radius of the coil is 60 mm, and the distance between each superconducting layer is 190 µm.…”

Section: Assessing Coil Performancementioning

confidence: 99%

Numerical Simulation of the Performance of High-Temperature Superconducting Coils

Ainslie

Zermeño

et al. 2016

J Supercond Nov Magn

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The Bulk Superconductivity Group at the University of Cambridge is currently investigating the use of high-temperature superconducting (HTS) materials in wire and bulk form in order to increase the electrical and magnetic loadings of an axial gap, trapped flux-type superconducting electric machine. As part of this research, accurate 2D axisymmetric and 3D finite element models of superconducting coils have been developed to investigate and simulate their electromagnetic behaviour. Some of the recent advances in analysing the performance of HTS coils are highlighted, including the simulation of in-field performance and increasing the computational speed and accuracy of 3D models. Experimental and simulation results on the DC characterisation of a test circular, epoxy-impregnated HTS coil are used to interpret the effects of degradation due to epoxy impregnation from the coil's ideal performance. With this numerical modelling framework, it is possible to simulate a variety of complex devices in both 2D and 3D over a broad range of electromagnetic situations with good accuracy.

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Modeling and Comparison of In-Field Critical Current Density Anisotropy in High-Temperature Superconducting (HTS) Coated Conductors

Abstract: J. (2016) 'Modelling and comparison of in-eld critical current density anisotropy in high temperature superconducting (HTS) coated conductors.', IEEE transactions on applied superconductivity., 26 (3). 6600906 .

Cited by 33 publications

References 23 publications

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Exploiting asymmetric wire critical current for the reduction of AC loss in HTS coil windings

Numerical Simulation of the Performance of High-Temperature Superconducting Coils

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