Limiteur de courant de défaut

Les limiteurs de courant de défaut sont des appareils électriques permettant de limiter la valeur du courant en cas de défaut électrique et notamment de court-circuit. Ces derniers sont en effet beaucoup plus élevés que les courants nominaux, ce qui impose de nombreuses contraintes dans le dimensionnement des autres appareils électriques d'un poste électrique. Par ailleurs, la valeur du courant de court-circuit augmente avec le nombre de centrales électriques connectées au réseau, il est donc possible que les équipements d'un poste ne soient plus adaptés aux contraintes en matière de court-circuit s'ils sont anciens. La mise en place d'un limiteur de courant peut alors permettre d'éviter d'avoir à remplacer des équipements. La manière la plus simple de limiter le courant de court-circuit est d'insérer une inductance en série avec la ligne électrique, que ce soit sous forme de bobine ou en choisissant des transformateurs ayant une impédance de court-circuit plus élevée. Toutefois cel

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Can Resistive-Type Fault Current Limiter Operate in Cryogen-Free Environment?

Bertrand Dutoit

Superconducting fault current limiters are unique devices that offer fast response to fault without need of an external triggering system. Therefore, they are interesting for industrial use, although their price is high. The principle of the resistive fault current limiter is based on the steep current-voltage characteristic of superconductors. When the current rises over the critical one, voltage on the superconductor rises steeply, and this mechanism blocks the increase of the current. Simultaneous appearance of voltage and current during this limiting period of operation generates a substantial amount of heat that is dissipated in the superconducting wire causing a rapid increase of its temperature. In this contribution, we further develop the idea that, during a limiting period, there is only a small difference between cooling by liquid nitrogen and adiabatic conditions. Using this approach, one can think about a current limiter free from a liquid coolant using a cryocooler. In this contribution, we discuss main differences in cooling conditions and test the idea on a short sample of the high-temperature superconductor REBCO conductor. We compare the behavior of identical samples cooled to the same temperature by liquid nitrogen and conduction cooled. If the realization can be achieved, the huge benefit would be an FCL with a tunable triggering current via its operating temperature.

Ieee-Inst Electrical Electronics Engineers Inc2016

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Technical and Economical Impacts on a Power System by Introducing an HTS FCL

Marten Sjöström

Fault current limiters (FCLs) can be considered as key elements in power systems using high temperature superconductors. This analysis takes into account the system benefits provided by the introduction of FCLs in various network configurations. New meshing possibilities, alternative grounding method and increase of power transmission are highlighted. It is the desire of most power system utilities to maximise transferred power and to reduce system losses to a minimum in their systems. These goals could be achieved if the system impedance could be reduced. However, such measures would increase short-circuit currents enormously and endanger equipment and people's safety. This problem could be circumvented by the installation of an FCL. FCLs are often implemented in combination with transformers but the transformer itself could also be designed having an integrated current limiting functionality.

2001

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Status of the European Union Project FASTGRID

Bertrand Dutoit, Mathias Noe, Frédéric Sirois

High voltage direct current super-grids are one attractive solution for the transmission of bulk power of renewable electricity over long distances. Their protection is still an issue and superconducting fault current limiters (SCFCL) offer attractive perspectives. However, the actual superconducting tapes are not yet properly designed for operation at high voltages (>100 kV): The electric field developed during the current limitation is still too low (approximately 50 V/m for 50 ms) and the limiter requires too long lengths of tape. The European project FASTGRID aims at improving the properties of the REBCO tapes to enhance significantly (by 2-3 times) the electric field limit and so the economical SCFCL attractiveness. We use advanced THEVA tapes. Substantial improvements are also planned on the stabilizer (shunt) layer. Several shunt ways are under investigations. Other improvement on the tape properties will be carried out, namely the increase of the normal zone propagation velocity by at least one order of magnitude, with the help of the innovative current flow diverter architecture. The optimized conductor will be used in a SCFCL module (approximate to 1.5 kA-50 kV) tested at 65 K. We will monitor the temperature along the conductor using an attached optical fibre. FAST-GRID will also develop innovative tapes based on sapphire substrate, which can tolerate very high electric fields, in the range of kilovolts per meter. Validated on the laboratory scale, this game-changing technology needs to be implemented at long lengths with an industrial process. We will provide an overview of the project and its first results.

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

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Supraconducteur à haute température

Un supraconducteur à haute température (en anglais, high-temperature superconductor : high- ou HTSC) est un matériau présentant une température critique de supraconductivité relativement élevée par r

Electrical resistance and conductance

The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrica

MSE-438: Superconducting electronics: A materials perspective

Introduction to superconducting electronic applications and their material requirements, including the fundamental phenomenology of superconductors. Key applications and their material requirements: a) magnets; b) quantum metrology; c) quantum computation.