EP1267376A1 - Self actuated power switch - Google Patents

Abstract

Power switch comprises a power contact arrangement having adjustable switching pieces made from electrically conducting material. <??>Power switch comprises a power contact arrangement having adjustable switching pieces (3, 4) made from electrically conducting material. In the on-position, the switching pieces form an intermediate chamber and are mechanically and electrically connected to each other via a fused contact element (14) made from electrically conducting material having a melting point which is lower than the melting point of the material of the switching pieces. A gas source is present which releases a gas to blast the contact element. <??>Preferred Features: The gas source is a container with a gas under pressure, preferably a gas generator (15) containing a gas-producing material consisting of a fuel and an oxidizer. The fuel is made from guanidine or guanidine compound. The oxidizer is a nitrate, chlorate, perchlorate or permanganate.

Description

Technical field

The invention relates to a power switching device according to the Preamble of claim 1, which in particular for Switching fault currents is suitable.

State of the art

Known circuit breakers are used as an interruption a current, the switching pieces of the switch contact arrangement with the help of a mechanical drive from its on position moved to the off position. The one when separating the switching pieces between these are burning arcs blow through a gas from a pressure volume and at next zero crossing of the current deleted. The pressure in Pressure volume is generated by a piston, which is also is driven by the drive for the contact pieces (see e.g. B. DE-A-198 16 505). As a result, he learns from many components existing switch drive an additional load and must be dimensioned accordingly. This means that the manufacturing costs for the Drive has a noticeable impact on total costs.

Presentation of the invention

The invention is based on the object of a power switching device to create that also high fault currents can switch, but in comparison to conventional Circuit breakers are of simpler construction.

According to the invention, this object is achieved by means of the features of claim 1 having power switching device solved.

When a fault current of a certain size occurs brought the melt contact element to melt. Between the spaced-apart contact pieces is now a Arc ignited, causing movement of the contact pieces in their off position causes. For an additional one mechanical drive for separating the contact pieces can therefore to be dispensed with. As a supplier for the for blowing the Arc required gas serves a gas source, preferably a gas generator arranged in the area of the switching pieces, from the outside by means of an ignition signal or by Effect of the heat generated by the arc activated becomes.

Preferred further developments of the invention Power switching device form the subject of the dependent Expectations.

Brief description of the drawings

Fig. 1a

einen axialen Längsschnitt durch ein erfindungsgemässes Leistungsschaltgerät gemäss einem ersten Ausführungsbeispiel,

Fig. 1b

einen Schnitt entlang der Linie I-I in Fig. 1a,

Fig. 2

einen axialen Längsschnitt durch einen Bereich des Schaltergehäuses mit einem Kühlelement,

Fig. 3a

in einem vergrösserten axialen Längsschnitt den Bereich eines Schmelzkontaktelementes mit einer ersten Ausführungsform eines Auslöseelementes zum Auslösen des Schmelzvorganges,

Fig. 3b

einen Schnitt entlang der Linie III-III in Fig. 3a,

Fig. 4a

in einem vergrösserten axialen Längsschnitt den Bereich eines Schmelzkontaktelementes mit einer zweiten Ausführungsform eines Auslöseelementes zum Auslösen des Schmelzvorganges,

Fig. 4b

einen Schnitt entlang der Linie IV-IV in Fig. 4a,

Fig. 5a

einen axialen Längsschnitt durch ein erfindungsgemässes Leistungsschaltgerät gemäss einem zweiten Ausführungsbeispiel, und

Fig.5b

einen Schnitt entlang der Linie V-V in Fig. 5a.

The invention is explained in more detail below with reference to figures which merely represent exemplary embodiments. It shows purely schematically

Fig. 1a

3 shows an axial longitudinal section through a power switching device according to the invention in accordance with a first exemplary embodiment,

Fig. 1b

a section along the line II in Fig. 1a,

Fig. 2

an axial longitudinal section through a region of the switch housing with a cooling element,

Fig. 3a

in an enlarged axial longitudinal section the area of a fuse contact element with a first embodiment of a trigger element for triggering the melting process,

Fig. 3b

a section along the line III-III in Fig. 3a,

Fig. 4a

in an enlarged axial longitudinal section the area of a fuse contact element with a second embodiment of a trigger element for triggering the melting process,

Fig. 4b

a section along the line IV-IV in Fig. 4a,

Fig. 5a

an axial longitudinal section through a power switching device according to the invention according to a second embodiment, and

5 b

a section along the line VV in Fig. 5a.

Ways of Carrying Out the Invention

The purely schematically shown in Figs. 1a and 1b Power switching device 1 has a housing 2 from a electrically insulating material in which two to one Switching contact arrangement belonging, electrically conductive Switch pieces 3.4 are housed. On every contact 3,4, a flexible electrical conductor 5,6 is connected, the by an end wall 7 or 8 of the Housing 2 is passed. Each contact piece is 3.4 guided in a sliding bearing 9 or 10 made of metal, that define itself in the direction of a switching axis 11 Longitudinal axis of the housing 2 extends. The plain bearings 9,10 are in a bearing part 12 made of an electrically insulating Material stored by one on the inner wall of the housing 2 adjacent bracket 13, which is also made an electrically insulating material is surrounded.

In their switch-on position shown in FIG Switch pieces 3,4 separated from each other by a space and a bridge that bridges this gap Melt contact element 14 mechanically and electrically with one another connected. The melt contact element 14 consists of an electrically conductive material whose melting point however, is deeper than that of the material of the contact pieces 3.4. The melt contact element 14 can, for example consist of an alloy made of the same materials (e.g. Ag, Cu, Al) like the contact pieces 3, 4 and additional ones Components that lower the melting point of the alloy, is composed. But it is also possible to use the fusible contact element 14 to produce from a sintered material from a conductor material, e.g. B. Ag that with another, the melting point lowering material, e.g. B. In, endowed is exists.

In a recess in the housing 2 and the bracket 13 a gas generator 15 serving as a gas source is arranged, the opposite the fuse contact element 14 in the radial direction and is directed towards an extinguishing chamber 16 in which is also the ends of the contact pieces 3, 4 and this connecting melt contact element 14 are. The arcing chamber 16 opens via an outlet opening 17 in the housing 2, which is diametrically opposite the gas generator 15, into one external exhaust space, not shown, which preferably as a closed exhaust volume is trained to rule out the risk to persons. In this outlet opening 17 is a cooling element 18 used to cool the escaping gases.

The gas generator 15 is constructed such that it is at its Activation produces a gas that contains as much nitrogen as possible, but contains little toxic combustion products. at In one embodiment, the gas generator 15 has, for example a gas generating material consisting of a Fuel and an oxidizer. The fuel can predominantly organic nitrogen compounds, in particular Guanidine or guanidine derivatives, possibly also contain an additive such as Mg, Al, Zr, Hf or Th. The Oxidator consists essentially of, for example Nitrates, chlorates, perchlorates or permanganates. To do that ignite gas generating material, d. H. the gas generator 11 to activate is preferably a conventional one, for a suitable ignition capsule used external ignition also has a fuel and an oxidizer. The Fuel mostly contains organic nitrogen compounds, in particular guanidine or guanidine derivatives, for example, while the oxidizer essentially consists of Nitrates, chlorates, perchlorates or permanganates exist. It is advantageous to use an ignition material that ignites safely at a given temperature.

Instead of a gas generator of the type described above a so-called cold gas generator can also be used, which is a gas with a temperature of less than 100 ° C generated. An example of a suitable cold gas generator is can be found in RU-C-2 108 282.

The operation of the power switching device 1 is like follows:

Reached in the event of a fault via the contact pieces 3,4 and the fusible contact element 14 flowing current Value that is equal to or greater than the fault current for which the fusible contact element 14 is designed so heated the material of the melt contact element 14 on his Melting temperature and the melt contact element 14 melts. An arc is ignited between the contact pieces 3, 4 which results in a pressure build-up in the arcing chamber 16. The arc's pinch pressure provides one essential contribution to building this pressure, which the drives two switching pieces 3.4 apart. The latter will be guided by the slide bearing 9, 10 along the switching axis 11 moved back to their off position. This movement of the Switch pieces 3.4 is used as impact elements trained end walls 7.8 limited.

Because of the heat radiated by the arc Ignition material of the gas generator 15 to its ignition temperature warmed and ignited, causing ignition of the gas-generating Leads. The resulting extinguishing gas the arc is blown intensively, which leads to such Increasing the bow tension helps that the Fault current is cleared at the next zero crossing. It is advantageous if that from the gas generator 15th escaping gas by means of a nozzle, not shown is led to the arc column as a result of Blowing is greatly extended. With such a measure the deletion process can be effectively supported. Which hot gases forming in the extinguishing chamber 16 pass through the outlet opening 17 in the aforementioned closed Exhaust volume off.

The ignition of the gas generator 15 can instead of as described through the heat radiation of the arc also with the help an ignition signal from an external ignition circuit is generated, triggered. Such an embodiment will be described with reference to Fig. 5a.

2 shows a possible embodiment of one of Metal existing cooling element 18 shown as already described in an outlet opening 17 in the housing 2 is used and the gas generator 15 diametrically opposite lies. This cooling element 18 has several at a distance perforated disks 19 arranged from each other. there are holes 20 in adjacent disks 19 laterally offset from one another that the cooling element 18 gas flow passing through it is deflected several times and the gas is effectively cooled. Through the special training of the cooling element 18 is furthermore that of the gas flow arcs driven to the cooling element 18, where the base points of the resulting partial arcs be actively cooled.

In the plain bearings 9,10 are at certain intervals Gaps 21 are provided. The subdivision achieved thereby the slide bearing 9,10 in several spaced apart Sections prevent the contact pieces from jamming 3.4 during their shifting movement and leads to a division of the arc into several partial arcs. The latter burn with their base points on the surface the metallic plain bearing sections. The one there Burning down leads to a cooling of these base points. The mentioned subdivision of the arc and the cooling The arc base points contribute significantly to a desired one Increase in bow tension at.

The gaps 21 between the sections of the slide bearings 9, 10 can be empty, as shown in FIG. 1 a, or filled with moldings from a cooling medium. Suitable cooling media are e.g. B. rock powders such as SiO ₂ , Al (OH) ₃ , Al ₂ O ₃ and TiO ₂ and nitrogen-donating materials, for. B. guanidines and guanidine derivatives.

3a, 3b and 4a, 4b, embodiments are shown, in which the fusible contact element 14 with the aid of a trigger element 22 is melted. The trigger element 22 is preferably designed so that at its Activation by means of an ignition signal an exothermic Reaction is triggered.

Surrounds in the variant shown in FIGS. 3a and 3b the trigger element 22 the melt contact element 14 while in the embodiment according to FIGS. 4a and 4b, the trigger element 22 inside the melt contact element 14 is arranged.

Preferably, the trigger element 22 consists essentially from a combustion material that contains a fuel and a Contains oxidizer, which when an ignition temperature is reached react with each other. The large amount of heat released in the process has a melting of the melt contact element 14 for Episode.

For example, guanidines and Guanidine derivatives, while as an oxidizer preferably oxygen-rich Compounds, especially nitrates, chlorates, Perchlorates and permanganates are used. To increase the thermal yield can the fuel or Oxidator substances are mixed that together with each other enter into a thermitic reaction, e.g. B. metals and metal oxides.

To bring the burn-up mass to its ignition temperature embedded in this an ignition element 23, which is connected to an ignition circuit is connected, which is an ignition signal for triggering of the ignition element 23 is generated, as is the case with the Embodiment according to FIG. 5a will be described.

Another embodiment is shown in FIGS. 5a and 5b of a power switching device 1 according to the invention, that differs from the first embodiment according to FIGS. 1a, 1b primarily by a different arrangement of the Gas generator differs.

5a shows two gas generators 15 in the housing 2 and 15a housed in the direction of the switching axis 11 are opposite. Each gas generator 15, 15a has one passage extending in the direction of the switching axis 11 24 or 25, through which one of the electrical conductors 5 or 6 extends through and in which the assigned Switch 3 or 4 when it is moved to the off position runs. The gas generators 15, 15a have also a gas-generating material that consists of a Fuel and an oxidizer. In the gas generating Material is an ignition trigger 26 made of a suitable ignition material embedded, which via a connecting line 27 with an output of an ignition circuit shown only schematically 28 is connected. The ignition circuit is on the input side 28 to one in Fig. 5a only schematically indicated current transformer 29 connected to the measurement of through the contact pieces 3,4 and the fuse contact element 14 flowing current is used. A second output of the ignition circuit 28 is connected via a connecting line 30 to the Ignition element 23 of the trigger element 22 connected, which like described with reference to FIGS. 3a, 3b and 4a, 4b serves a Melt the melt contact element 14 trigger.

In order to bring the gas generated by the gas generators 15, 15a into the region of the arc, ie to the quenching chamber 16, 12 channels 31 are provided in the bearing part, which extend in the direction of the switching axis 11 and connect the quenching chamber 16 to cavities 32 and 32a , which are provided adjacent to the gas generators 15 and 15a in the housing 2. An insert 34 containing an extinguishing agent 33 is arranged in the extinguishing chamber 16 in the region of the outlets of the channels 31. The extinguishing agent 33 is accommodated in a chamber 35, into which the channels 31 open and which is closed off towards the melt contact element 15 by a film 36. The film 36 should be impermeable to water vapor and can consist, for example, of metal or a polymer plastic. A very fine-grained oxide powder is preferably used as the extinguishing agent 33. Materials particularly suitable for this are SiO ₂ , Al (OH) ₃ , Al ₂ O ₃ and TiO ₂ .

The operation of the power switching device 1 according to the 5a, 5b is largely identical to that of 1a, 3a and 4a described embodiments and is summarized as follows:

When monitoring the 3.4 flowing current, a rapid increase in current was found, that suggests a fault current, so generates the Ignition circuit 28 ignition signals that are sent via the connecting line 30 the ignition element 23 of the trigger element 22 for the fusible contact element 14 and via the connecting line 27 fed to the ignition triggers 26 of the gas generators 15, 15a becomes. After the melting contact element 14 has melted an arc is ignited between the contact pieces 3, 4. At the same time, the activated gas generators 15, 15a generate one Gas, which is passed through the channels 31 to the arcing chamber 16 becomes. By the pressure of the flowing into the chamber 35 Gases the film 36 is destroyed. The powder particles of the Extinguishing agent 33 are finely distributed in the arc blown and melted, giving the arc energy is withdrawn. This cools the arc. Of course, by blowing the arc additionally the effect described with reference to FIG. 1a achieved.

It is also a variant of that shown in Figures 5a, 5b Power switching device 1 possible, on the one Extinguishing agent 33 containing insert 34 is dispensed with.

In a further variant of the power switching device 1 5a, 5b is dispensed with by means of external ignition signals to activate the gas generators 15, 15a and to bring the melt contact element 15 to melt. Rather, as in the exemplary embodiment according to FIG. 1a the melt contact element 14 through the flowing Residual current heated to the melting temperature and so to Brought melting. This triggers the ignition of an ignition element (not shown in Figs. 5a and 5b) from that of Area of the melt contact element 14 through the film 36 extends to the gas generators 15, 15a. After this Igniting burns the ignition element through the film 36 through which the extinguishing agent 33 of the insert 34 is released becomes. The ignition element then ignites the Gas generator 15.15a. This variant can also be used without the one Extinguishing agent 33 containing insert 34 can be realized.

The gas needed to blow the arc can also from gas sources other than the gas generators described 15, 15a are supplied, e.g. B. of compressed gas cylinders, which is activated when the melt contact element 14 melts become.

The power switching devices according to the invention come as described 1 without an additional mechanical Switch drive off, which has a cost-saving effect. Though can switch the power switching devices 1 only once. With a suitable modular structure, however, can be achieved that a large part of the components used can be used again. The inventive Power switching devices 1 are particularly suitable for using to be connected in series with a load switch. rated currents are switched by the load switch while the power switching device 1 takes over the switching of fault currents.

LIST OF REFERENCE NUMBERS

1

Power switching device

2

casing

3.4

switching piece

5.6

electrical conductor

7.8

end wall

9.10

bearings

11

switching axis

12

bearing part

13

bracket

14

Melting contact element

15,15a

gas generator

16

extinguishing chamber

17

outlet

18

cooling element

19

perforated disc

20

hole

21

gap

22

triggering element

23

igniter

24.25

passage

26

ignition trigger

27

connecting line

28

ignition circuit

29

Power converter

30

connecting line

31

channel

32,32a

cavity

33

extinguishing Media

34

commitment

35

chamber

36

foil

Claims (18)

Power switching device (1) with a switching contact arrangement, which has two switching pieces (3, 4) made of an electrically conductive material, which can be adjusted relative to one another along a switching axis (11) from a switch-on position to a switch-off position and which are axially spaced apart by a switching distance in the switch-off position and with an arrangement for generating a gas flow directed against the electric arc that forms when the switching pieces (3, 4) separate, characterized in that in the switched-on position the switching pieces (3, 4) form a space between them and via this space bridging fuse contact element (14) are mechanically and electrically connected to one another, which consists of an electrically conductive material, the melting point of which is lower than the melting point of the material of the switching elements (3, 4), and that at least one gas source which can be activated when the fuse contact element (14) melts is available t, which, after its activation, emits a gas for blowing the arc which burns after the melting of the melt contact element (14) between the switching pieces (3, 4) and thereby causes the arc to move into its switch-off position. Power switching device according to claim 1, characterized in that the gas source is a container with a pressurized gas. Power switching device according to claim 1, characterized in that the gas source is a gas generator (15, 15a) which generates a gas after its activation. Power switching device according to claim 1, characterized in that the fuse contact element (14) consists of an alloy which is composed of the materials used for the switching elements (3, 4) and additional components which lower the melting point of the alloy. Power switching device according to claim 1, characterized in that the melt contact element (14) is made of a sintered material which consists of an electrically conductive material, in particular Ag, and another material which lowers the melting point, preferably In. Power switching device according to one of claims 3 to 5, characterized in that the gas generator (15, 15a) contains a gas-generating material consisting of a fuel and an oxidizer. Power switching device according to claim 6, characterized in that the fuel contains organic nitrogen compounds, in particular guanidine or guanidine compounds. Power switching device according to claim 6 or 7, characterized in that the oxidizer consists essentially of nitrates, chlorates, perchlorates or permanganates. Power switching device according to one of Claims 6 to 8, characterized in that the gas generator (15, 15a) contains an ignition material which serves to ignite the gas-generating material and which preferably consists of a fuel and an oxidizer. Power switching device according to claim 3, characterized in that the gas generator is a cold gas generator. Power switching device according to one of Claims 3 to 10, characterized in that the gas generator (15) is arranged in the region of an arcing chamber (16) which surrounds the ends of the switching pieces (3, 4) in their switched-on position and the melt contact element (14) is. Power switching device according to one of Claims 3 to 10, characterized in that two gas generators (15, 15a) spaced apart from one another in the direction of the switching axis (11) are provided, which are connected via channels (31) with an arcing chamber located between the gas generators (15, 15a) (16) are connected, which surrounds the ends of the switching pieces (3, 4) which are in their switched-on position and the melt contact element (14). Power switching device according to one of Claims 3 to 12, characterized by an ignition circuit (28) connected to the gas generator (15) for generating an ignition signal which activates the gas generator (15). Power switching device according to one of Claims 1 to 13, characterized in that the fusible contact element (14) is connected to a trigger element (22) which can be activated by means of an ignition signal generated by an ignition circuit (28) and which, after activation, causes the fusible contact element to melt (14) causing heat is released, the trigger element (22) preferably containing a fuel and an oxidizer. Power switching device according to claim 11 or 12, characterized in that between the gas generator (15) or the gas generators (15, 15a) and the quenching chamber (16) there is a chamber (35) lying in the flow path of the gas which contains an extinguishing agent (33 ), preferably an extinguishing powder, in particular an oxide powder. Power switching device according to claim 11 or 12, characterized in that the quenching chamber (16) is connected via a cooling element (18) to a preferably closed exhaust space. Power switching device according to one of claims 1 to 16, characterized in that the switching pieces (3, 4) are guided in slide bearings (9, 10) which extend in the direction of the switching axis (11). Power switching device according to claim 17, characterized in that the sliding bearings (9, 10) are provided with spaces (21) spaced apart from one another in the direction of the switching axis (11), which are preferably filled with a cooling medium, for example a powdered rock.

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