Magnetic and Transport AC Losses in HTS Roebel Cable

Lakshmi, L. Seetha; Long, N.J.; Badcock, Rodney A.; Staines, M.P.; Jiang, Zhenan; Thakur, K.P.; Emhofer, Johann

doi:10.1109/tasc.2010.2088369

Cited by 13 publications

(18 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The AC loss results per cycle at each frequency agree very well in the high current region although there is some disagreement between the results in the low assembly-current region. This minor difference might be due to the frequency dependence of AC loss in some HTS wires [13,14], however the frequency independence of the results at higher currents confirms that the is hysteretic.…”

Section: B Coil Assembly Ac Loss Measurementmentioning

confidence: 88%

AC Loss Measurements in a Hybrid REBCO/BSCCO Coil Assembly

Jiang

Staines

Long

et al. 2017

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Wire cost and AC loss are paramount issues for the future uptake of HTS AC machines. In particular, new approaches which reduce the total manufacturing cost of HTS coils are critical to the future commercial uptake of HTS technology. Here, we present the results of AC loss measurements s of a hybrid HTS coil assembly comprising end windings (EWs) wound with BSCCO wire and a central winding (CW) wound with REBCO wire. As a cost mitigation measure, we have chosen to use REBCO wire which possesses a relatively low self-field Ic at 77 K, equating to approximately half that of the BSCCO wire.Transport AC loss measurements were made on the total coil assembly at both 77 K and 65 K, using a recently developed lockin amplifier approach. We show the AC losses in the assembly at these temperatures scale with the overall transport critical current threshold of the hybrid coil assembly. The results are then compared with a reference coil assembly having similar geometrical dimensions, and in which both the EWs and CW were wound with identical BSCCO wire. Surprisingly we observe that the AC loss of the hybrid coil is lower than that of the BSCCO coil, despite the CW of the hybrid coil employing wire a lower overall average Ic. We attribute this effect to the lower AC loss of coated conductor REBCO wire under parallel field, which is the dominant field orientation in the CW region.Based on this observation we conclude that hybrid assembly design is a good design strategy for HTS coil assemblies, enabling both wire cost and AC loss to be balanced.

show abstract

Section: B Coil Assembly Ac Loss Measurementmentioning

confidence: 88%

AC Loss Measurements in a Hybrid REBCO/BSCCO Coil Assembly

Jiang

Staines

Long

et al. 2017

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

show abstract

“…In [87] the authors manufactured a coupled cable (which is more stable against defects) by coupling the strands by means of Cu-bridges: the coupled cable showed the dominance of coupling currents at low frequencies and a saturation of loss at high field, a situation where the cable behaves as a monolithic conductor with higher loss than that of an uncoupled cable. for publication in Superconductor Science and Technology.…”

Section: Magnetization Lossmentioning

confidence: 99%

“…The Version of Record is available online at http://dx.doi.org/10.1088/0953-2048/27/9/093001In[87] Lakshmi et al analyse the frequency dependence of the magnetization loss for two types of Roebel cables: an "uncoupled cable" (where the strands are electrically insulated from each other) and a "coupled cable" (where the strands are not individually insulated and some degree of coupling is present). A very weak frequency dependence of the magnetization loss is reported for the uncoupled cable: losses decrease with frequency at low fields and increase with frequency at…”

mentioning

confidence: 99%

Roebel cables from REBCO coated conductors: a one-century-old concept for the superconductivity of the future

Goldacker

Grilli

Pardo

et al. 2014

Supercond. Sci. Technol.

249

139

View full text Add to dashboard Cite

Energy applications employing high-temperature superconductors (HTS), such as motors/generators, transformers, transmission lines and fault current limiters, are usually operated in the alternate current (AC) regime. In order to be efficient, the HTS devices need to have a sufficiently low value of AC loss, in addition to the necessary current-carrying capacity. Most applications are operated with currents beyond the current capacity of single conductors and consequently require cabled conductor solutions with much higher current carrying capacity, from a few kA to up to 20-30 kA for large hydro-generators.A century ago, in 1914, Ludwig Roebel invented a low-loss cable design for copper cables, which was successively named after him. The main idea behind Roebel cables is to separate the current in different strands and to provide a full transposition of the strands along the cable direction. Nowadays, these cables are commonly used in the stator of large generators. Based on the same design concept of their conventional material counterparts, HTS Roebel cables from REBCO coated conductors were first manufactured at the Karlsruhe Institute of Technology (KIT) and have been successively developed in a number of varieties that provide all the required technical features such as fully transposed strands, high transport currents and low AC losses, yet retaining enough flexibility for a specific cable design. In the past few years a large number of scientific papers have been published on the concept, manufacturing and characterization of such cables. Times are therefore mature for a review of those results. The goal is to provide an overview and a succinct and easy-to-consult guide for users, developers, and manufacturers of this kind of HTS cables.

show abstract

“…There have already been several reports on the magnetization loss in Roebel cables, measured at the University of Kyoto [15], Industrial Research Ltd [16], [17], [18], Ohio State University [19], [20] and KIT [21], [22], [22]. However data is at 77 K and at frequencies above 10 Hz (in most cases the angular dependence is not considered).…”

Section: Introductionmentioning

confidence: 99%

Measurement and Numerical Evaluation of AC Losses in a ReBCO Roebel Cable at 4.5 K

Nugteren

Gao

et al. 2016

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Abstract-EUCARD2 aims to research ReBCO superconducting magnets for future accelerator applications. The properties of ReBCO conductors are very different from low temperature superconductors. To investigate dynamic field quality, stability and normal zone propagation an electrical network model for coated conductor cables was developed. To validate the model two identical samples were prepared at CERN after which measurements were taken at the University of Twente and Southampton University. The model predicts that for Roebel cable, in a changing magnetic field applied in the perpendicular direction, the hysteresis loss is much larger than the coupling loss. In the case of a changing magnetic field applied parallel to the cable coupling loss is dominant. In the first case the experiment is in good agreement with the model. In the second case the data can only be compared qualitatively because the calibration for the inductive measurement is not available.

show abstract

Magnetic and Transport AC Losses in HTS Roebel Cable

Cited by 13 publications

References 12 publications

AC Loss Measurements in a Hybrid REBCO/BSCCO Coil Assembly

AC Loss Measurements in a Hybrid REBCO/BSCCO Coil Assembly

Roebel cables from REBCO coated conductors: a one-century-old concept for the superconductivity of the future

Measurement and Numerical Evaluation of AC Losses in a ReBCO Roebel Cable at 4.5 K

Contact Info

Product

Resources

About