Nexans SuperConductors GmbH

Hürth, Germany

Nexans SuperConductors GmbH

Hürth, Germany
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Fagnard J.-F.,Royal Military Academy | Elschner S.,Mannheim University of Applied Sciences | Elschner S.,Nexans SuperConductors GmbH | Bock J.,Nexans SuperConductors GmbH | And 3 more authors.
Superconductor Science and Technology | Year: 2010

We show that tubes of melt cast Bi-2212 used as current leads for LTS magnets can also act as efficient magnetic shields. The magnetic screening properties under an axial DC magnetic field are characterized at several temperatures below the liquid nitrogen temperature (77 K). Two main shielding properties are studied and compared with those of Bi-2223, a material that has been considered in the past for bulk magnetic shields. The first property is related to the maximum magnetic flux density that can be screened, B lim; it is defined as the applied magnetic flux density below which the field attenuation measured at the centre of the shield exceeds 1000. For a cylinder of Bi-2212 with a wall thickness of 5 mm and a large ratio of length over radius, Blim is evaluated to 1 T at T = 10 K. This value largely exceeds the Blim value measured at the same temperature on similar tubes of Bi-2223. The second shielding property that is characterized is the dependence of Blim with respect to variations of the sweep rate of the applied field, dBapp/dt. This dependence is interpreted in terms of the power law E = Ec(J/Jc)n and allows us to determine the exponent n of this E(J ) characteristics for Bi-2212. The characterization of the magnetic field relaxation involves very small values of the electric field. This gives us the opportunity to experimentally determine the E(J ) law in an unexplored region of small electric fields. Combining these results with transport and AC-shielding measurements, we construct a piecewise E(J ) law that spans over eight orders of magnitude of the electric field. © 2010 IOP Publishing Ltd.


Fagnard J.-F.,SUPRATECS | Elschner S.,Mannheim University of Applied Sciences | Hobl A.,Nexans SuperConductors GmbH | Bock J.,Nexans SuperConductors GmbH | And 2 more authors.
Superconductor Science and Technology | Year: 2012

This paper deals with the magnetic properties of bulk high temperature superconducting cylinders used as magnetic shields. We investigate, both numerically and experimentally, the magnetic properties of a hollow cylinder with two axial slits which cut the cylinder in equal halves. Finite element method modelling has been used with a three-dimensional geometry to help us in understanding how the superconducting currents flow in such a cut cylinder and therefore how the magnetic shielding properties are affected, depending on the magnetic field orientation. Modelling results show that the slits block the shielding current flow and act as an entrance channel for the magnetic flux lines. The contribution of the slits to the total flux density that enters the cylinder is studied through the angle formed between the applied field and the internal field. The modelled data agree nicely with magnetic shielding properties measured on a bulk Bi-2212 hollow cylinder at 77K. The results demonstrate that the magnetic flux penetration in such a geometry can be modelled successfully using only two parameters of the superconductor (constant J c and n value), which were determined from magnetic measurements on the plain cylinder. © 2012 IOP Publishing Ltd.


Dommerque R.,Nexans SuperConductors GmbH | Kramer S.,Nexans SuperConductors GmbH | Hobl A.,Nexans SuperConductors GmbH | Bohm R.,Nexans SuperConductors GmbH | And 7 more authors.
Superconductor Science and Technology | Year: 2010

In 2008/09 Nexans SuperConductors GmbH made the step from R&D activities to the production of the first non-publicly funded fault-current limiter units. In close cooperation with two customers, Applied Superconductor Limited (ASL, UK) and Vattenfall (Germany), Nexans was able to design, produce and deliver two resistive superconducting limiter devices. Both devices are designed for the medium voltage grid and were tested at the high voltage and high power lab IPH in Berlin. The superconducting components of both limiters, coils of bulk MCP BSCCO-2212, have been designed and produced by Nexans. © 2010 IOP Publishing Ltd.


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ENERGY.2009.7.3.1 | Award Amount: 4.64M | Year: 2010

The project aims at developing a unique device for electricity networks: A superconducting fault current limiter (SFCL) based on coated conductor YBCO tape (cc-tape) or 2nd Generation HTS tape. The general trend in Europe to a higher meshing of distribution networks and the rapid growing integration of renewable energy sources leads to an increase of the fault current level by every new installation. As substations ratings are coming to their limits network operators have to either decline additional installations to their grids or to upgrade if not rebuild complete substations. The SFCL provides a solution to deal with the increasing incidence and level of fault currents and will contribute to improving the performance, stability and efficiency of electricity grids. It can be applied as a new tool for grid operation and will enhance the flexibility for further grid planning. SFCL are considered to be the most attractive superconducting devices as they offer unparalleled features compared to conventional techniques such as automatic ultrafast and effective current limitation, no external trigger (fail safe), rapid self recovery and negligible impedance during operation. In contrast to conventional solutions resistive type SFCL are also suitable for higher voltage levels. So far developed SFCL prototypes based on BSCCO material are exhibiting significant AC-losses at higher currents which oppose their commercial introduction. Today, the availability of cc-tape in longer lengths at reasonable cost makes a commercial breakthrough of FCL possible with unique features such as compactness, short recovery-time, low AC-losses. Leading industrial and academic institutions from Europe have teamed up to design, build, and test the first full 3-phase cc-tape FCL worldwide. The device will be long term tested or even permanently installed in the medium voltage grid. The strong demand for this device is emphasized by the large number of electric utilities participating as partner


Bjoerstad R.,CERN | Scheuerlein C.,CERN | Rikel M.O.,Nexans SuperConductors GmbH | Ballarino A.,CERN | And 6 more authors.
Superconductor Science and Technology | Year: 2015

The strain induced critical current degradation of overpressure processed straight Bi-2212/Ag wires has been studied at 77 K in self-field. For the first time superconducting properties, lattice distortions, composite wire stress and strain have been measured simultaneously in a high energy synchrotron beamline. A permanent Ic degradation of 5% occurs when the wire strain exceeds 0.60%. At a wire strain of about 0.65% a drastic n-value and Ic reduction occur, and the composite stress and the Bi-2212 lattice parameter reach a plateau, indicating Bi-2212 filament fracturing. The x-ray diffraction measurements show that Bi-2212 exhibits linear elastic behaviour up to the irreversible strain limit. © 2015 IOP Publishing Ltd.


Stemmle M.,Nexans Deutschland GmbH | Merschel F.,RWE AG | Noe M.,Karlsruhe Institute of Technology | Hofmann L.,Leibniz University of Hanover | Hobl A.,Nexans SuperConductors GmbH
Physics Procedia | Year: 2012

This paper presents results of a study investigating a permanent grid deployment of medium voltage superconductor cables in combination with superconducting fault current limiters within a typical urban area power system. A completely new grid concept, which only becomes feasible through the use of superconductor cable systems, is shown. Further, several different cable options, including superconducting and conventional cables, are compared. © 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Guest Editors.


Stemmle M.,Nexans Deutschland GmbH | Merschel F.,RWE AG | Noe M.,Karlsruhe Institute of Technology | Hobl A.,Nexans SuperConductors GmbH
2013 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2013 | Year: 2013

In this paper the German AmpaCity project, which started in September 2011, will be introduced and the conceptual design of the main components will be described. The objective of the project is developing, manufacturing and installing a 10 kV, 40 MVA high temperature superconducting (HTS) system consisting of a fault current limiter and of a 1 km cable in the city of Essen. AmpaCity serves as a lighthouse project, since it is the first time that a one kilometer HTS cable system will be installed together with an HTS fault current limiter in a real grid application within a city center area. In addition it will be the longest installed HTS cable system worldwide. Within the project the development phase was finished in March 2013 with successfully completing the type test of the cable system. Subsequently, manufacturing of the different components for the installation has started and the system is expected to be commissioned by the end of 2013. © 2013 IEEE.


Stemmle M.,Nexans Deutschland GmbH | Merschel F.,RWE AG | Noe M.,Karlsruhe Institute of Technology | Hobl A.,Nexans SuperConductors GmbH
2013 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2013 | Year: 2013

High temperature superconducting (HTS) power cables can provide electric utilities with a new way to solve power distribution issues in densely populated urban areas. Compared to conventional cable technologies, based on copper or aluminum, HTS cables can either carry several times more power at the same voltage due to the huge current transport capacity of HTS materials which is more than 150 times that of copper, or carry the same amount of power at a lower voltage level. As long as the current carried by the cable is below the so-called critical current of the cable, HTS cables exhibit no ohmic power loss for direct currents and just very small losses for alternating currents (AC). High temperature superconductor materials typically used in cables are tapes with critical current densities of > 100 A/mm2 when cooled in liquid nitrogen. Consequently, cables made of these conductors can carry large currents within very small dimensions. In addition, HTS cables are especially suited for densely-populated areas as they do not exhibit any electromagnetic or thermal impact on the environment, and only require a very narrow right-of-way, basically limited to the cable itself. © 2013 IEEE.


Stemmle M.,Nexans Deutschland GmbH | Merschel F.,RWE AG | Noe M.,Karlsruhe Institute of Technology | Hobl A.,Nexans Super Conductors GmbH
Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference | Year: 2014

In this paper the German AmpaCity project, which started in September 2011, will be introduced and the conceptual design of the main components will be described. The objective of the project is developing, manufacturing and installing a 10 kV, 40 MVA high temperature superconducting (HTS) system consisting of a fault current limiter and of a 1 km cable in the city of Essen. AmpaCity serves as a lighthouse project, since it is the first time that a one kilometer HTS cable system will be installed together with an HTS fault current limiter in a real grid application within a city center area. In addition it will be the longest installed HTS cable system worldwide. Within the project the development phase was finished in March 2013 with successfully completing the type test of the cable system. Subsequently, manufacturing of the different components for the installation has started and the system is expected to be commissioned by the end of 2013. © 2014 IEEE.


Hobl A.,Nexans SuperConductors GmbH | Bock J.,Nexans SuperConductors GmbH | Allweins K.,Nexans Deutschland GmbH
Refrigeration Science and Technology | Year: 2012

The application of high temperature superconductors (HTS) in power engineering requires both efficient and reliable cooling. Several superconducting cables and fault-current limiters have been designed and installed by Nexans and were already thoroughly field tested. Dependent on the cooling power, temperature and pressure conditions, various solutions were realised and have resulted in different experiences during the field tests. Each system shows specific advantages and drawbacks, and in some cases improvements had been established even after commissioning or during the test period. The operating behaviour was not satisfying in all cases since high effort would be needed to ensure continuous operation and higher efficiency. A main reason is seen in the fact that the typical cooling demand is in a range of a few kW, a domain where large-series coolers are not available to date.

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