EP1026720B1 - Self restoring current limiting device with liquid metal - Google Patents

Self restoring current limiting device with liquid metal Download PDF

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Publication number
EP1026720B1
EP1026720B1 EP20000101319 EP00101319A EP1026720B1 EP 1026720 B1 EP1026720 B1 EP 1026720B1 EP 20000101319 EP20000101319 EP 20000101319 EP 00101319 A EP00101319 A EP 00101319A EP 1026720 B1 EP1026720 B1 EP 1026720B1
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Prior art keywords
current limiting
limiting device
liquid metal
liquid
partitions
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EP20000101319
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German (de)
French (fr)
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EP1026720A1 (en
Inventor
Wolfgang Kremers
Frank Berger
Andreas Krätzschmar
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Eaton Industries GmbH
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Moeller GmbH
Kloeckner Moeller GmbH
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H87/00—Protective devices in which a current flowing through a liquid or solid is interrupted by the evaporation of the liquid or by the melting and evaporation of the solid when the current becomes excessive, the circuit continuity being reestablished on cooling

Definitions

  • the invention relates to a self-recovering current-limiting device with liquid metal according to the preamble of claim 1 or claim 7.
  • Such a current-limiting device which contains electrodes made of solid metal, which are separated by first insulating body designed as a pressure-resistant insulating housing. Within the insulating housing are formed by insulating intermediate walls and interposed second insulating body, which are designed as annular sealing discs with liquid metal partially filled, one behind the other compressor spaces, which are connected to each other via filled with liquid metal, off-center connection channels of the intermediate walls.
  • first insulating body designed as a pressure-resistant insulating housing.
  • second insulating body which are designed as annular sealing discs with liquid metal partially filled, one behind the other compressor spaces, which are connected to each other via filled with liquid metal, off-center connection channels of the intermediate walls.
  • the electrical connection of the electrodes is interrupted via the liquid metal, which leads to the limitation of the short-circuit current.
  • the connecting channels fill again with liquid metal, whereupon the current limiting device is ready for operation again.
  • a current limiting device is described with only one compressor chamber and mentioned as a medium above the liquid level vacuum, inert gas or an insulating liquid. It is known from document DE 26 52 506 A1 to use gallium alloys, in particular GaInSn alloys, in contact devices.
  • the electrodes of solid metal for connection to a protective circuit and a plurality of liquid metal partially filled compressor compartments, which are open at the top and annularly formed between insulation includes.
  • a non-conductive liquid that is immiscible and non-bondable with the liquid metal.
  • the liquid metal is displaced due to electrodynamic forces from the compressor chambers.
  • the invention is therefore based on the object to improve the current limiting behavior of a current limiting device, in particular with regard to their current limiting factor and their response time.
  • the proposed means are compared to the known current limiting devices alone under the action of a short-circuit current, the arc ignition and thus the beginning of the current limit advanced both in time and in dependence on the amount of short-circuit current.
  • the porous material of the intermediate walls sucks due to the capillary action with the non-conductive liquid, which is thus available directly on the walls of the connecting channels.
  • the area of each connecting channel is very much heated by the current racks, and it comes to the evaporation of the non-conductive liquid that has passed through the pores in this area.
  • vapor bubbles form in the connecting channel, which lead to constriction of the conductive cross section. This process develops like an avalanche, as the narrowed cross-section leads to even more heating, until finally the liquid metal itself evaporates and an electric arc is ignited.
  • the boiling point of the non-conductive liquid must be well above the heating temperature in nominal operation, but also well below the boiling point of the liquid metal. Furthermore, the non-conductive liquid must not mix or chemically bond with the liquid metal.
  • the capillary action on the nonconducting liquid is substantially greater than the capillary action on the liquid metal.
  • nonconducting liquid which additionally protects the liquid metal from adverse chemical and physical changes, in particular from oxidation; protects.
  • the nonconducting liquid is an oil, in particular an organic oil having a boiling point of 250 to 350 ° C.
  • an alcohol or a mixture of alcohols, deionized water or a mixture of deionized water and at least one alcohol is to be used with advantage as a nonconductive liquid.
  • the porous material of the intermediate walls "sucks" with the inert protective gas, which is thus available directly on the walls of the connecting channels.
  • the area of each connecting channel is very much heated by the current racks, and it comes to the escape of the protective gas, which through the Pores has entered this area.
  • gas bubbles form in the connecting channel, which lead to constriction of the conductive cross section. This process develops like an avalanche, as the narrowed cross-section leads to even more heating, until finally the liquid metal itself evaporates and an electric arc is ignited.
  • the protective gas consists of nitrogen or of a noble gas or noble gas mixture or of a mixture of nitrogen and at least one noble gas.
  • the partition walls can be advantageously produced from an open-cell foam ceramic or porous, porous mica.
  • GaInSn alloys are easy to handle due to their physiological safety.
  • An alloy of 660 parts by weight of gallium, 205 parts by weight of indium and 135 parts by weight of tin is liquid under normal pressure of 10 ° C to 2000 ° C and has sufficient electrical conductivity.
  • the current-limiting device 10 contains on both sides an electrode 1 made of solid metal, preferably copper, which is rotationally symmetrical and merges into an outer connecting conductor 2. Between The electrodes 1 are a plurality of compressor chambers 4, which are formed by a corresponding number of annular sealing disks 11 and insulating partitions 12. By a mold housing 5, the electrodes 1, the sealing discs 11 and the intermediate walls 12 are held, with known means for sealing the compressor chambers 4 and the non-positive connection of the mold housing 5 mounted elements 1, 11 and 12 are provided, but not shown for reasons of clarity are.
  • the means for sealing can be, for example, sealing rings between the sealing disks 11 and the intermediate walls 12 or electrodes 1.
  • the means for non-positive connection for example, continuous clamping screws along the two lines 3.
  • the two outer compressor chambers 4 are each bounded laterally by one of the electrodes 1 and by an intermediate wall 12.
  • the inner compressor chambers 4 are each bounded laterally by two intermediate walls 12.
  • the generally multi-part mold housing 5 and the sealing washers 11 are pressure-resistant first and second insulating body. All compressor chambers 4 are partially filled with a liquid metal 7, for example a GaInSn alloy.
  • the intermediate walls 12 are provided below the liquid level 9 with connecting channels 8.
  • the connecting channels 8 are also filled with liquid metal 7, so that there is a continuous electrically conductive connection between the electrodes 1.
  • the connecting channels 8 of adjacent intermediate walls 12 can advantageously be offset by a certain angle in order to prevent a continuous arc in the current limiting case.
  • liquid metal 7 there is a sufficiently thick layer of a non-conductive liquid 6, which can neither mix nor chemically combine with the liquid metal 7, for example an organic oil having a boiling point of about 300 ° C.
  • a non-conductive liquid 6 which can neither mix nor chemically combine with the liquid metal 7, for example an organic oil having a boiling point of about 300 ° C.
  • the partitions 12 are made of an open-porous material, such as ceramic foam. Due to the capillary action of the pores on the nonconductive liquid 6, it is partially absorbed by the intermediate walls 12, so that it also reaches the immediate area of the connecting channels 8.
  • the current limiting device 20 differs from the one described above in that an inert protective gas 16, for example argon, is located above the liquid level 9.
  • the protective gas 16 has reached the immediate area of the connecting channels 8 via the pores of the intermediate walls 12.
  • the protective gas 16 extending close to the connecting channels 8 expands due to the resulting heat, whereby an increasing constriction of the current paths and further heating of the liquid metal 7 in the connecting channels 8 takes place as a result of the part of the protective gas 16 entering the connecting channels 8 , which eventually leads to the rapid ignition of a current-limiting arc.

Description

Die Erfindung betrifft eine selbsterholende Strombegrenzungseinrichtung mit Flüssigmetall nach dem Oberbegriff des Anspruches 1 oder des Anspruches 7.The invention relates to a self-recovering current-limiting device with liquid metal according to the preamble of claim 1 or claim 7.

Aus der Druckschrift SU 922 911 A ist eine solche Strombegrenzungseinrichtung bekannt, die Elektroden aus Festmetall enthält, die durch als druckfestes Isoliergehäuse ausgebildete erste Isolierkörper getrennt sind. Innerhalb des Isoliergehäuses sind durch isolierende Zwischenwände und dazwischen angeordnete zweite Isolierkörper, die als ringförmige Dichtscheiben ausgeführt sind, mit Flüssigmetall teilweise aufgefüllte, hintereinander liegende Verdichterräume ausgebildet, die untereinander über mit Flüssigmetall ausgefüllte, außermittig angeordnete Verbindungskanäle der Zwischenwände verbunden sind. Damit besteht im Normalbetrieb über das Flüssigmetall eine durchgehende innere leitende Verbindung zwischen den Elektroden. Im Strombegrenzungsfall wird infolge der hohen Stromdichte das Flüssigmetall aus den Verbindungskanälen verdrängt. Damit ist die elektrische Verbindung der Elektroden über das Flüssigmetall unterbrochen, was zur Begrenzung des Kurzschlußstromes führt. Nach Abschaltung oder Beseitigung des Kurzschlusses füllen sich die Verbindungskanäle wieder mit Flüssigmetall, worauf die Strombegrenzungseinrichtung erneut betriebsbereit ist. In der Druckschrift DE 40 12 385 A1 wird eine Strombegrenzungseinrichtung mit nur einem Verdichterraum beschrieben und als Medium über dem Flüssigkeitsspiegel Vakuum, Schutzgas oder eine isolierende Flüssigkeit erwähnt. Es ist nach Druckschrift DE 26 52 506 A1 bekannt, bei Kontakteinrichtungen Gallium-Legierungen, insbesondere GaInSn-Legierungen zu verwenden.From the document SU 922 911 A, such a current-limiting device is known which contains electrodes made of solid metal, which are separated by first insulating body designed as a pressure-resistant insulating housing. Within the insulating housing are formed by insulating intermediate walls and interposed second insulating body, which are designed as annular sealing discs with liquid metal partially filled, one behind the other compressor spaces, which are connected to each other via filled with liquid metal, off-center connection channels of the intermediate walls. Thus, in normal operation, there is a continuous internal conductive connection between the electrodes via the liquid metal. In the current limiting case, the liquid metal is displaced from the connecting channels due to the high current density. Thus, the electrical connection of the electrodes is interrupted via the liquid metal, which leads to the limitation of the short-circuit current. After switching off or elimination of the short circuit, the connecting channels fill again with liquid metal, whereupon the current limiting device is ready for operation again. In the document DE 40 12 385 A1 a current limiting device is described with only one compressor chamber and mentioned as a medium above the liquid level vacuum, inert gas or an insulating liquid. It is known from document DE 26 52 506 A1 to use gallium alloys, in particular GaInSn alloys, in contact devices.

Aus der US-PS 3 474 339 ist eine selbsterholende Strombegrenzungseinrichtung bekannt, die Elektroden aus Festmetall zum Anschließen an einen zu schützenden Stromkreis und mehrere mit Flüssigmetall teilweise aufgefüllte Verdichterräume, die nach oben offen und zwischen Isolierungen ringförmig ausgebildet sind, enthält. Über dem Flüssigmetall lagert eine nichtleitende Flüssigkeit, die unvermischbar sowie unverbindbar mit dem Flüssigmetall ist. Im Strombegrenzungsfall und bei gleichzeitiger Druckentlastung der nichtleitenden Flüssigkeit wird das Flüssigmetall infolge elektrodynamischer Kräfte aus den Verdichterräumen verdrängt.From US-PS 3 474 339 a self-recovering current limiting device is known, the electrodes of solid metal for connection to a protective circuit and a plurality of liquid metal partially filled compressor compartments, which are open at the top and annularly formed between insulation includes. Above the liquid metal is a non-conductive liquid that is immiscible and non-bondable with the liquid metal. In the current limiting case and with simultaneous pressure relief of the non-conductive liquid, the liquid metal is displaced due to electrodynamic forces from the compressor chambers.

Bei Strombegrenzungseinrichtungen mit mehreren Verdichterräumen wird infolge der hintereinander liegenden Verbindungskanäle beim Auftreten eines Kurzschlusses durch die Anzahl der strombegrenzenden Teillichtbögen ein entsprechend hoher Spannungsabfall aufgebaut, der schließlich zur Unterbrechung des Kurzschlußstromes führt. Die bekannten Strombegrenzungseinrichtungen weisen allerdings einen zu hohen Strombegrenzungsfaktor, das heißt ein zu hohes Verhältnis zwischen Durchlaßstrom und zu begrenzendem Kurzschlußstrom, auf.In current limiting devices having a plurality of compressor compartments, a correspondingly high voltage drop is established as a result of the connection channels lying one behind the other when a short circuit occurs due to the number of current-limiting partial arcs, which ultimately leads to the interruption of the short-circuit current. However, the known current-limiting devices have too high a current limiting factor, that is, too high a ratio between the forward current and the short-circuit current to be limited.

Der Erfindung liegt daher die Aufgabe zugrunde, das Strombegrenzungsverhalten einer Strombegrenzungseinrichtung, insbesondere hinsichtlich ihres Strombegrenzungsfaktors und ihrer Ansprechzeit, zu verbessern.The invention is therefore based on the object to improve the current limiting behavior of a current limiting device, in particular with regard to their current limiting factor and their response time.

Ausgehend von einer Strombegrenzungseinrichtung der eingangs genannten Art wird die Aufgabe erfindungsgemäß durch die kennzeichnenden Merkmale der unabhängigen Ansprüche gelöst, während den abhängigen Ansprüchen vorteilhafte Weiterbildungen der Erfindung zu entnehmen sind.Starting from a current limiting device of the type mentioned, the object is achieved by the characterizing features of the independent claims, while the dependent claims advantageous developments of the invention can be seen.

Durch die vorgeschlagenen Mittel werden gegenüber den bekannten Strombegrenzungseinrichtungen allein unter der Einwirkung eines Kurzschlußstromes die Lichtbogenzündung und damit der Beginn der Strombegrenzung sowohl zeitlich als auch in Abhängigkeit von der Höhe des Kurzschlußstromes vorverlegt.The proposed means are compared to the known current limiting devices alone under the action of a short-circuit current, the arc ignition and thus the beginning of the current limit advanced both in time and in dependence on the amount of short-circuit current.

Nach der ersten Lösung saugt sich das poröse Material der Zwischenwände infolge der Kapillarwirkung mit der nichtleitenden Flüssigkeit voll, die somit direkt an den Wänden der Verbindungskanäle zur Verfügung steht. Durch einen äußeren Kurzschlußstrom wird der Bereich jedes Verbindungskanals durch die Stromengestelle sehr stark erwärmt, und es kommt zur Verdampfung der nichtleitenden Flüssigkeit, die durch die Poren in diesen Bereich gelangt ist. Dabei bilden sich im Verbindungskanal Dampfblasen, welche zur Einengung des leitfähigen Querschnitts führen. Dieser Prozeß entwickelt sich lawinenartig, da der verengte Querschnitt zu einer noch stärkeren Erwärmung führt, bis schließlich das Flüssigmetall selbst verdampft und ein elektrischer Lichtbogen gezündet wird. Hierzu muß der Siedepunkt der nichtleitenden Flüssigkeit deutlich über der Erwärmungstemperatur im Nennbetrieb, aber auch deutlich unter der Siedetemperatur des Flüssigmetalls liegen. Weiterhin darf sich die nichtleitende Flüssigkeit nicht mit dem Flüssigmetall vermischen oder chemisch verbinden. Bei der Wahl des Flüssigmetalls, der nichtleitenden Flüssigkeit und des porösen Materials ist zu beachten, daß die Kapillarwirkung auf die nichtleitende Flüssigkeit wesentlich größer als die Kapillarwirkung auf das Flüssigmetall ist.After the first solution, the porous material of the intermediate walls sucks due to the capillary action with the non-conductive liquid, which is thus available directly on the walls of the connecting channels. By an external short-circuit current, the area of each connecting channel is very much heated by the current racks, and it comes to the evaporation of the non-conductive liquid that has passed through the pores in this area. In this case, vapor bubbles form in the connecting channel, which lead to constriction of the conductive cross section. This process develops like an avalanche, as the narrowed cross-section leads to even more heating, until finally the liquid metal itself evaporates and an electric arc is ignited. For this purpose, the boiling point of the non-conductive liquid must be well above the heating temperature in nominal operation, but also well below the boiling point of the liquid metal. Furthermore, the non-conductive liquid must not mix or chemically bond with the liquid metal. When choosing the liquid metal, the non-conductive liquid and the porous material, it should be noted that the capillary action on the nonconducting liquid is substantially greater than the capillary action on the liquid metal.

Es ist von Vorteil, eine nichtleitende Flüssigkeit zu verwenden, die das Flüssigmetall zusätzlich vor nachteiligen chemischen und physikalischen Veränderungen, insbesondere vor Oxidation; schützt. Vorteilhaft ist die nichtleitende Flüssigkeit ein Öl, insbesondere ein organisches Öl mit einer Siedetemperatur von 250 bis 350 °C. Anderseits ist als nichtleitende Flüssigkeit mit Vorteil auch ein Alkohol oder ein Gemisch von Alkoholen, deionisiertes Wasser oder ein Gemisch aus deionisiertem Wasser und wenigstens einem Alkohol zu verwenden.It is advantageous to use a nonconducting liquid which additionally protects the liquid metal from adverse chemical and physical changes, in particular from oxidation; protects. Advantageously, the nonconducting liquid is an oil, in particular an organic oil having a boiling point of 250 to 350 ° C. On the other hand, an alcohol or a mixture of alcohols, deionized water or a mixture of deionized water and at least one alcohol is to be used with advantage as a nonconductive liquid.

Nach der zweiten Lösung "saugt" sich das poröse Material der Zwischenwände mit dem inerten Schutzgas, das somit direkt an den Wänden der Verbindungskanäle zur Verfügung steht. Durch einen äußeren Kurzschlußstrom wird der Bereich jedes Verbindungskanals durch die Stromengestelle sehr stark erwärmt, und es kommt zum Austritt des Schutzgases, das durch die Poren in diesen Bereich gelangt ist. Dabei bilden sich im Verbindungskanal Gasblasen, welche zur Einengung des leitfähigen Querschnitts führen. Dieser Prozeß entwickelt sich lawinenartig, da der verengte Querschnitt zu einer noch stärkeren Erwärmung führt, bis schließlich das Flüssigmetall selbst verdampft und ein elektrischer Lichtbogen gezündet wird.According to the second solution, the porous material of the intermediate walls "sucks" with the inert protective gas, which is thus available directly on the walls of the connecting channels. By an external short-circuit current, the area of each connecting channel is very much heated by the current racks, and it comes to the escape of the protective gas, which through the Pores has entered this area. In this case, gas bubbles form in the connecting channel, which lead to constriction of the conductive cross section. This process develops like an avalanche, as the narrowed cross-section leads to even more heating, until finally the liquid metal itself evaporates and an electric arc is ignited.

Es ist von Vorteil, ein Schutzgas, zu verwenden, welches das Flüssigmetall zusätzlich vor nachteiligen chemischen und physikalischen Veränderungen, insbesondere vor Oxydation, schützt. Vorteilhaft besteht das Schutzgas aus Stickstoff oder aus einem Edelgas bzw. Edelgasgemisch oder aus einem Gemisch aus Stickstoff und wenigstens einem Edelgas.It is advantageous to use a protective gas, which additionally protects the liquid metal from adverse chemical and physical changes, in particular from oxidation. Advantageously, the protective gas consists of nitrogen or of a noble gas or noble gas mixture or of a mixture of nitrogen and at least one noble gas.

Die Zwischenwände lassen sich vorteilhaft aus einer offenporigen Schaumkeramik oder aus offenporigem, porösem Glimmer herstellen.The partition walls can be advantageously produced from an open-cell foam ceramic or porous, porous mica.

Mit Vorteil ist als Flüssigmetall eine Gallium-Legierung zu verwenden. Insbesondere GaInSn-Legierungen sind einfach zu handhaben durch ihre physiologische Unbedenklichkeit. Eine Legierung aus 660 Gewichtsanteilen Gallium, 205 Gewichtsanteilen Indium und 135 Gewichtsanteilen Zinn ist bei Normaldruck von 10°C bis 2000°C flüssig und besitzt eine ausreichende elektrische Leitfähigkeit.It is advantageous to use a gallium alloy as liquid metal. In particular, GaInSn alloys are easy to handle due to their physiological safety. An alloy of 660 parts by weight of gallium, 205 parts by weight of indium and 135 parts by weight of tin is liquid under normal pressure of 10 ° C to 2000 ° C and has sufficient electrical conductivity.

Weitere Einzelheiten und Vorteile der Erfindung ergeben sich aus dem folgenden, anhand von Figuren erläuterten Ausführungsbeispielen. Es zeigen

Figur 1:
im Längsschnitt eine erste Ausführungsform der erfindungsgemäßen Strombegrenzungseinrichtung;
Figur 2:
im Längsschnitt eine zweite Ausführungsform der erfindungsgemäßen Strombegrenzungseinrichtung.
Further details and advantages of the invention will become apparent from the following, with reference to figures explained embodiments. Show it
FIG. 1:
in longitudinal section a first embodiment of the current limiting device according to the invention;
FIG. 2:
in longitudinal section a second embodiment of the current limiting device according to the invention.

Die Strombegrenzungseinrichtung 10 nach Fig. 1 enthält zu beiden Seiten je eine Elektrode 1 aus Festmetall, vorzugsweise Kupfer, die rotationssymmetrisch ausgebildet ist und in einen äußeren Anschlußleiter 2 übergeht. Zwischen den Elektroden 1 befinden sich mehrere Verdichterräume 4, die durch eine entsprechende Anzahl von ringförmigen Dichtscheiben 11 sowie von isolierenden Zwischenwänden 12 gebildet werden. Durch ein Formgehäuse 5 werden die Elektroden 1, die Dichtscheiben 11 und die Zwischenwände 12 gehalten, wobei bekannte Mittel zum Abdichten der Verdichterräume 4 und zum kraftschlüssigen Verbinden der im Formgehäuse 5 gelagerten Elemente 1, 11 und 12 vorgesehen, jedoch aus Gründen der Übersichtlichkeit nicht dargestellt sind. Die Mittel zum Abdichten können beispielsweise Dichtringe zwischen den Dichtscheiben 11 und den Zwischenwänden 12 bzw. Elektroden 1 sein. Die Mittel zum kraftschlüssigen Verbinden sind beispielsweise durchgehende Spannschrauben entlang der beiden Linien 3. Die beiden äußeren Verdichterräume 4 werden seitlich jeweils durch eine der Elektroden 1 sowie durch eine Zwischenwand 12 begrenzt. Die inneren Verdichterräume 4 werden seitlich jeweils durch zwei Zwischenwände 12 begrenzt. Das im allgemeinen mehrteilige Formgehäuse 5 und die Dichtscheiben 11 sind druckfeste erste bzw. zweite Isolierkörper. Alle Verdichterräume 4 sind teilweise mit einem Flüssigmetall 7 ausgefüllt, beispielsweise einer GaInSn-Legierung. Die Zwischenwände 12 sind unterhalb des Flüssigkeitsspiegels 9 mit Verbindungskanälen 8 versehen. Die Verbindungskanäle 8 sind ebenfalls mit Flüssigmetall 7 gefüllt, so daß zwischen den Elektroden 1 eine durchgehende elektrisch leitende Verbindung besteht. Die Verbindungskanäle 8 benachbarter Zwischenwände 12 können vorteilhaft jeweils um einen bestimmten Winkelbetrag versetzt sein, um im Strombegrenzungsfall einen durchgehenden Lichtbogen zu verhindern. Über dem Flüssigmetall 7 befindet sich eine ausreichend dicke Schicht einer nichtleitenden Flüssigkeit 6, die sich mit dem Flüssigmetall 7 weder vermischen noch chemisch verbinden kann, beispielsweise ein organisches Öl mit einer Siedetemperatur von etwa 300 °C. Oberhalb der Flüssigkeit 6 besteht in den Verdichterräumen 4 Vakuum. Die Zwischenwänden 12 bestehen aus einem offenporigen, porösen Material, beispielsweise aus Schaumkeramik. Durch die Kapillarwirkung der Poren auf die nichtleitende Flüssigkeit 6 wird diese von den Zwischenwänden 12 teilweise aufgesaugt, so daß sie auch in den unmittelbaren Bereich der Verbindungskanäle 8 gelangt. Im Kurzschlußfall verdampft ein Teil der den Verbindungskanälen 7 nahen nichtleitenden Flüssigkeit 6, wodurch in sehr kurzer Zeit eine zunehmende Verengung der Strompfade und eine weitere Erhitzung des Flüssigmetalls 7 in den Verbindungskanälen 8 stattfindet, was schließlich zum raschen Zünden eines strombegrenzenden Lichtbogens führt.The current-limiting device 10 according to FIG. 1 contains on both sides an electrode 1 made of solid metal, preferably copper, which is rotationally symmetrical and merges into an outer connecting conductor 2. Between The electrodes 1 are a plurality of compressor chambers 4, which are formed by a corresponding number of annular sealing disks 11 and insulating partitions 12. By a mold housing 5, the electrodes 1, the sealing discs 11 and the intermediate walls 12 are held, with known means for sealing the compressor chambers 4 and the non-positive connection of the mold housing 5 mounted elements 1, 11 and 12 are provided, but not shown for reasons of clarity are. The means for sealing can be, for example, sealing rings between the sealing disks 11 and the intermediate walls 12 or electrodes 1. The means for non-positive connection, for example, continuous clamping screws along the two lines 3. The two outer compressor chambers 4 are each bounded laterally by one of the electrodes 1 and by an intermediate wall 12. The inner compressor chambers 4 are each bounded laterally by two intermediate walls 12. The generally multi-part mold housing 5 and the sealing washers 11 are pressure-resistant first and second insulating body. All compressor chambers 4 are partially filled with a liquid metal 7, for example a GaInSn alloy. The intermediate walls 12 are provided below the liquid level 9 with connecting channels 8. The connecting channels 8 are also filled with liquid metal 7, so that there is a continuous electrically conductive connection between the electrodes 1. The connecting channels 8 of adjacent intermediate walls 12 can advantageously be offset by a certain angle in order to prevent a continuous arc in the current limiting case. Above the liquid metal 7 there is a sufficiently thick layer of a non-conductive liquid 6, which can neither mix nor chemically combine with the liquid metal 7, for example an organic oil having a boiling point of about 300 ° C. Above the liquid 6 there is a vacuum in the compressor chambers 4. The partitions 12 are made of an open-porous material, such as ceramic foam. Due to the capillary action of the pores on the nonconductive liquid 6, it is partially absorbed by the intermediate walls 12, so that it also reaches the immediate area of the connecting channels 8. In the event of a short circuit, a part of the connecting channels 7 evaporates close non-conductive liquid 6, which takes place in a very short time, an increasing narrowing of the current paths and further heating of the liquid metal 7 in the connecting channels 8, which eventually leads to the rapid ignition of a current-limiting arc.

Die Strombegrenzungseinrichtung 20 nach Fig. 2 unterscheidet sich von der vorstehend beschriebenen dadurch, daß sich über dem Flüssigkeitsspiegel 9 ein inertes Schutzgas 16, beispielsweise Argon, befindet. Das Schutzgas 16 ist über die Poren der Zwischenwände 12 bis in den unmittelbaren Bereich der Verbindungskanäle 8 gelangt. Im Kurzschlußfall dehnt sich durch die entstehende Wärme das den Verbindungskanälen 8 nahen Schutzgases 16 aus, wodurch infolge des in die Verbindungskanäle 8 eintretenden Teil des Schutzgases 16 in sehr kurzer Zeit eine zunehmende Verengung der Strompfade und eine weitere Erhitzung des Flüssigmetalls 7 in den Verbindungskanälen 8 stattfindet, was schließlich zum raschen Zünden eines strombegrenzenden Lichtbogens führt.The current limiting device 20 according to FIG. 2 differs from the one described above in that an inert protective gas 16, for example argon, is located above the liquid level 9. The protective gas 16 has reached the immediate area of the connecting channels 8 via the pores of the intermediate walls 12. In the event of a short circuit, the protective gas 16 extending close to the connecting channels 8 expands due to the resulting heat, whereby an increasing constriction of the current paths and further heating of the liquid metal 7 in the connecting channels 8 takes place as a result of the part of the protective gas 16 entering the connecting channels 8 , which eventually leads to the rapid ignition of a current-limiting arc.

Claims (13)

  1. A self-restoring current limiting device with liquid metal, containing electrodes (1) of solid metal for connection to a circuit to be protected and a plurality of compressor chambers (4) partially filled with liquid metal (7) and arranged in succession between the electrodes (1), which compressor chambers (4) are formed by pressure-resistant insulators (5; 11) and, held thereby, insulating partitions (12) with connecting channels (8), wherein a non-conductive liquid (6) is located above the liquid metal (7), which non-conductive liquid (6) is immiscible and non-combinable with the liquid metal (7) and the boiling temperature of which is distinctly below the boiling temperature of the liquid metal (7) and distinctly above the heating temperature under nominal conditions, characterised in that the partitions (12) consist of an open-pored, porous material and, under the influence of capillary forces in the partitions (12), the non-conductive liquid (6) borders onto the connecting channels (8).
  2. A self-restoring current limiting device according to claim 1, characterised in that the non-conductive liquid (6) is an oil.
  3. A self-restoring current limiting device according to claim 2, characterised in that the non-conductive liquid (6) is an organic oil with a boiling temperature of 250 to 350°C.
  4. A self-restoring current limiting device according to claim 1, characterised in that the non-conductive liquid (6) is an alcohol or a mixture of alcohols.
  5. A self-restoring current limiting device according to claim 1, characterised in that the non-conductive liquid (6) is deionised water.
  6. A self-restoring current limiting device according to claim 1, characterised in that the non-conductive liquid (6) is a mixture of deionised water and at least one alcohol.
  7. A self-restoring current limiting device with liquid metal, containing electrodes (1) of solid metal for connection to a circuit to be protected and a plurality of compressor chambers (4) partially filled with liquid metal (7) and arranged in succession between the electrodes (1), which compressor chambers (4) are formed by pressure-resistant insulators (5; 11) and, held thereby, insulating partitions (12) with connecting channels (8), characterised in that the partitions (12) consist of an open-pored, porous material and in that an inert protective gas (16) is located above the liquid metal (7), which inert protective gas (16) borders over the pores of the partitions (12) onto the connecting channels (8).
  8. A current limiting device according to claim 7, characterised in that the protective gas (16) is nitrogen.
  9. A current limiting device according to claim 7, characterised in that the protective gas (16) is a noble gas or a mixture of noble gases.
  10. A current limiting device according to claim 7, characterised in that the protective gas (16) is a mixture of nitrogen and at least one noble gas.
  11. A current limiting device according to any one of claims 1 to 10, characterised in that the partitions (12) consist of a foam ceramic.
  12. A current limiting device according to any one of claims 1 to 10, characterised in that the partitions (12) consist of mica.
  13. A current limiting device according to any one of the preceding claims, characterised in that the liquid metal (7) is a GaInSn alloy.
EP20000101319 1999-02-01 2000-01-22 Self restoring current limiting device with liquid metal Expired - Lifetime EP1026720B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1999103940 DE19903940C1 (en) 1999-02-01 1999-02-01 Self-recovering current limiting device with liquid metal
DE19903940 1999-02-01

Publications (2)

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EP1026720A1 EP1026720A1 (en) 2000-08-09
EP1026720B1 true EP1026720B1 (en) 2006-07-05

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DE (2) DE19903940C1 (en)

Cited By (1)

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CN109637874A (en) * 2018-11-21 2019-04-16 云南靖创液态金属热控技术研发有限公司 Liquid metal current limiter

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DE10226062A1 (en) 2002-06-12 2004-01-08 Ab Elektronik Gmbh Wide-angle sensor
DE102005050044A1 (en) * 2005-10-19 2007-05-03 Moeller Gmbh Device for current limitation

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DE383037C (en) * 1922-03-21 1923-10-09 Michael Von Hirschberg Permanent electrical fuse with mercury filling
CH273223A (en) * 1946-02-19 1951-01-31 Fkg Ag Device for limiting electrical currents.
CH308101A (en) * 1952-08-19 1955-06-30 Fkg Ag Arc-proof insulating body.
FR1503721A (en) * 1966-10-11 1967-12-01 Centre Nat Rech Scient Improvements to electrical switches for intense currents
FR2025319A5 (en) * 1969-10-27 1970-09-04 Mitsubishi Electric Corp
DE2652506A1 (en) * 1976-11-18 1978-05-24 Gec Elliott Automation Ltd Heavy current switchgear with several moving contacts - has at least one solid contact wetted on surface with liq. gallium or its alloy
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109637874A (en) * 2018-11-21 2019-04-16 云南靖创液态金属热控技术研发有限公司 Liquid metal current limiter
CN109637874B (en) * 2018-11-21 2020-01-17 云南靖创液态金属热控技术研发有限公司 Liquid metal current limiter

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DE19903940C1 (en) 2000-11-02
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