EP0951039A1 - Power switch - Google Patents

Abstract

An escape vent goes out from each pressure chamber (25a, 25b) to a vent volume (30a, 30b).

Description

Technical field

The invention relates to a circuit breaker, as in Power plants, substations and other facilities of the Electrical energy supply for switching on and off Operating and overcurrents are used.

State of the art

From EP-B-0 177 714 is a generic Circuit breaker known in which the pressure volume is only about the heating volume is connected to the exhaust. thats why an immediate relief of the pressure chamber at high Amperages not possible. To avoid excess pressure with large currents, the pressure chamber and heating volume must be like this be designed accordingly, so that the pressure build-up at smaller flows make only a small contribution to the extinction of the arc. With the known Generic circuit breaker is to avoid Therefore pressurize the arc space directly with the exhaust connected. A similarly constructed circuit breaker is known from EP-A-0 456 139.

In the circuit breaker according to DE-A-196 13 568 the Arc crossed by the gas flow and very effective blown, but only a part of the by Heating of the gas by the pressure built up by the arc used for blowing, so for most Areas of application a relatively large dimension additional mechanical blowing device is required.

Presentation of the invention

In contrast, the invention is based on the object Specify generic switch at which the Arc energy output, especially pinch pressure as effective as possible for blowing the arc is exploited so that even with high switching capacities and without large, high performance of the switch drive mechanical blowing devices required a quick Interruption of the circuit is guaranteed. At the same time however, the switch should be overloaded by overpressure avoided at very high currents.

This is according to the invention by the features of Claim 1 reached, which ensure that the Arc after strong pressure build-up in the extinguishing gas at least Blowing intensively over a large part of its length and is effectively cooled thereby. The connection of the Pressure chamber with the exhaust volume also ensures that overpressures are reduced quickly.

The formation of the Circuit breaker according to the invention according to claim 2, since this training is very strong thanks to the high pressure Gas flow inevitably crosses the arc and thereby dissolves and safely interrupts.

Other particularly advantageous designs are the further claims.

Brief description of the drawings

Fig. 1

einen teilweisen axialen Längsschnitt durch einen Leistungsschalter gemäss einer ersten Ausführungsform der Erfindung,

Fig. 2

einen axialen Längsschnitt durch die Abbrandschaltanordnung eines Leistungsschalters gemäss einer zweiten Ausführungsform der Erfindung, wobei in der rechten Hälfte die Schnittebene gegenüber der linken Hälfte um 45° gedreht ist,

Fig. 3a

einen axialen Längsschnitt durch die Abbrandschaltanordnung eines Leistungsschalters gemäss einer dritten Ausführungsform der Erfindung und

Fig. 3b

einen Querschnitt längs B-B in Fig. 3a.

In the drawings, several exemplary embodiments are shown, which only serve to explain the invention. Show it

Fig. 1

a partial axial longitudinal section through a circuit breaker according to a first embodiment of the invention,

Fig. 2

3 shows an axial longitudinal section through the erosion switching arrangement of a circuit breaker according to a second embodiment of the invention, the cutting plane in the right half being rotated through 45 ° with respect to the left half,

Fig. 3a

an axial longitudinal section through the erosion switching arrangement of a circuit breaker according to a third embodiment of the invention and

Fig. 3b

a cross section along BB in Fig. 3a.

Ways of Carrying Out the Invention

The one in Fig. 1, left in the on position, right in Open position, circuit breaker shown according to According to a first embodiment, a housing 1 has the a switching axis 2 is essentially rotationally symmetrical with an upper housing part 3 and a lower housing part 4, both made of metal, which by a cylindrical middle housing part 5 made of insulating material are. The housing parts 3, 4 are each with the opposite connections of the circuit breaker connected.

At the level of the middle housing part 5 there is an outside Rated current path, which are each on the upper Housing part 3 and the lower housing part 4, circumferentially spaced apart in the axial direction fixed nominal current contacts, an upper fixed Rated current contact 6 and a lower fixed Nominal current contact 7 includes and a movable Rated current contact 8 with in the circumferential direction successive, each the distance between the fixed nominal current contacts 6, 7 bridging Contact fingers. The movable nominal current contact 8 is with a switching drive, not shown, connected by which he is in the axial direction between the Switch-on position, in which he the gap between the upper fixed nominal current contact 6 and the lower bridged fixed current contact 7 and the Switch-off position, in which it from the upper fixed Nominal current contact 6 is spaced, is displaceable.

The upper housing part 3 is through a horizontal partition 9 completed down. It carries the fixed part a burn-up switching arrangement 10. In a central opening the partition 9 is the first switching piece a contact tulip 11 stored with several in the circumferential direction successive, diagonally down and against the Switching axis 2 directed, separated by slots elastic contact fingers. The contact tulip 11 opposite is a nozzle 12 surrounding the switching axis 2 made of electrical insulating material arranged in the shape of a has a funnel narrowing upwards. In one in lower housing part 4 arranged slide guide 13, which also establishes a good electrical connection as a second contact piece axially by means of the switching drive movable switching pin 14 mounted in the Switch-on position protrudes into the contact tulip 11 and from its Contact fingers is touched on the outside. The same will happen elastically deformed so that they are proportionate exert high contact pressure on switching pin 14. The Slideway 13 is anchored to a partition 15, which closes the lower housing part 4 upwards. In a The central opening of the partition 15 is the nozzle 12 attached.

In the off position, the switching pin 14 is down drawn so that its tip is below the nozzle 12. Is between the contact tulip 11 and the switching pin 14 then an arc space 16, in which between the said switching elements has formed an arc 17. The arc room 16 is of a coherent surrounded annular heating volume 18 that with it through the the contact tulip 11 from the nozzle 12 separating gap, the forms a peripheral blow slot 19, is connected. Outside is the heating volume 18 through a peripheral wall 20 made of insulating material. On the partition 15 are several, e.g. B. four distributed over the circumference Blow cylinder 21 actuated by the shift drive Blow piston 22 arranged, each with blow channels 23 with the heating volume 18 are connected. In the mouths of the Blow channels 23 in the heating volume 18 are each Check valves 24 installed.

At the top of the arc space 16, separated from the latter by the opening formed by the ends of the contact fingers of the contact tulip 11, is a pressure chamber 25, which extends through the upwardly extending contact tulip 11 and a subsequent annular cover 26 and a cap 27, both made of electrically insulating material, the latter surrounding the cover 26 at a distance and abutting the partition 9 outside it, is limited. The cover 26 and the cap 27 spaced from it form between them a return channel 28 which is rotationally symmetrical about the switching axis 2 and which leads radially outwards from the pressure chamber 25 on all sides, so that its cross section widens there continuously, and then bends downward and in the axial direction is led to the heating volume 18. A check valve 29 is installed in the mouth of the return duct 28 into the heating volume 18. A central exhaust opening 31 is provided in the cap 27 as an exhaust, which connects the pressure chamber 25 to the interior of the upper housing part 3, which serves as an exhaust volume 30. A further exhaust volume 30 ′ in the lower housing part 4 adjoins the arc space 16 below. The entire housing 1 is filled with an insulating gas, preferably SF ₆ .

The pressure chamber 25 and the return duct 28, possibly also the heating volume 18 can be several millimeters thick layer of a suitable material lined be, e.g. B. with polyoxymethylene, very high molecular weight Polyethylene, polypropylene, plexiglass, polytetrafluoroethylene, Melamine resins or other plastics that may be with strong steam-generating inclusions can be offset. There the quality requirements are not very high, too Recycled be used. If pressure chamber, return duct and possibly heating volume not as shown in electrically insulating material existing parts, but those made of metal are such Lining particularly useful as it is the Metal vapor entry into the insulating gas, which leads to a Deterioration of the dielectric properties of the same leads, significantly reduced. Furthermore, through Evaporation of the material increases the amount of gas and the gas pressure and at the same time energy is absorbed, which is both Improves the extinguishing effect.

Switching off takes place as follows:

Through the switching drive, not shown, starting from the switch-on position shown on the left, the Movable nominal current contact 8, the switching pin 14 and the Blow piston 22 moved down. Shortly after the start of this Movement separates the movable nominal current contact 8 from upper fixed nominal current contact 6, whereby the Nominal current path is interrupted and the current on the Burn-up switching arrangement 10 commutates. A little later the Switch pin 14 pulled out of the contact tulip 11. Between an arcing 17 forms in these contact pieces at the end of the switching movement through the arc space 16 extends through the movement of the switching pin 14 the switching path was opened. By the arc 17 through the blow slot 19 into the heating volume 18 radiated heat, the insulating gas becomes strong in the same heated so that there is a high pressure in the heating volume 18 developed.

The pressure build-up is supported by the movement of the Blow piston 22, which an insulating gas flow from the Blow piston 21 via the blow channels 23 into the heating volume 18 causes. If the one built up by other influences Pressure exceeds the blowing pressure, they close Check valves 24 and prevent gas from escaping from the heating volume 18 into the blowing channels 23.

Another very important contribution to pressure building in Heating volume 18 is determined by the pinch pressure of the arc 17 delivered by a rapid contraction of the same is generated in the area of the switching axis 2 and briefly a strong axial flow from the arc space 16 in the Pressure chamber 25 and a strong increase in pressure in the same evokes. This pressure is partly exerted on the Return duct 28 derived into the heating volume 18. It is it is favorable that the flow resistance in the return duct 28 thanks to the expansion of the cross section of the same and its direct management and installation-free training very low is. The check valve 29 at the mouth of the Return channel 28 in the heating volume 18 in turn prevents that the gas flows out of the heating volume 18 when the Print the one in the pressure room 25, the usual declines relatively quickly, surpasses.

With very high currents, such a high pinch pressure is generated that full recirculation of the gas into that Heating volume for mechanical and thermal overload of the Burn-up switching arrangement 10 would have to lead. Excess Pressure is therefore directly into the exhaust port 31 Exhaust volume 30 derived. The central arrangement of the Exhaust opening 31 is advantageous because it is oversized Pinch pressure primarily generates an axial pressure surge that escapes harmlessly through the exhaust opening 31, while the general pressure build-up in the pressure chamber 25 is not essential being affected. It therefore depends relatively little on the current.

After building up a high pressure in the heating volume 18 at the next zero crossing the arc 17 extinguished, by the insulating gas from the heating volume 18 for one part through the blow slot 19 and the contact tulip 11 in the Pressure chamber 25, in which the pressure at this time has already fallen sharply, and continues through the Exhaust opening 31 flows into the exhaust volume 30. Here the gas flow inevitably crosses the arc path and largely removes all ionized ones in the intersection area Gases so that there is no arc after the zero crossing can train more. On the other hand, the insulating gas flows parallel to the arc path 16 through the nozzle 12 ins further exhaust volumes 30 '.

In the burn-up switching arrangement shown in FIG. 2 according to the second embodiment of the invention Circuit breaker that is otherwise essentially the same can be constructed like the circuit breaker according to the first embodiment, corresponds in basic structure and many details of those described there Burn-up switching arrangement. However, the first contact piece next to a contact tulip 11a one of the same in Switch-off direction upstream, with it electrically conductive connected combustion ring 32a, the inside diameter is slightly larger than the diameter of the Switch pin 14. The second switching piece includes next to the axially displaceable switching pin 14 one with the partition 15 electrically contacting fixed contact tulip 11b and also a fixed one, the contact tulip 11b in Switching direction upstream, with it electrically conductive connected burn ring 32b. The two burn rings 32a, b lie against each other, in each case by a ring 33a or 33b shielded by electrically insulating material and by the circumferential blow slot 19, the one of a circumferential Wall 20 surrounded by electrically insulating material Heating volume 18 with the between the burn rings 32a, b lying arc room 16 connects, separately opposite.

Check valves 24 open into heating volume 18 closed blow channels 23, which do the same with (not connect) blow cylinders. In the axial Continuation of the arc room 16 are pressure rooms on both sides 25a, b provided laterally by annular Covers 26a, b of the contact tulips 11a, b are limited. The Covers 26a, b and the surrounding them at a distance Caps 27a, b each form one between them Return channel 28a or 28b, which is only radially outwards is guided and then bends axially and to the heating volume 18th leads back into which it via a check valve 29a or 29b opens.

The pressure chamber 25a is over several, for. B. four exhaust pipes 34a, which start on its side wall and diagonally to are directed above and outside and the return channel 28a cross, connected to an exhaust volume 30a, the Pressure chamber 25b in the same way via corresponding Exhaust pipes 34b with an exhaust volume 30b. The one on the Pressure chamber 25a is arranged on the side of the first switching element also via a central, expanding upwards Relief opening 35 in the cap 27a with the Exhaust volume 30a connected, which, however, by a rounded conical piston 36 of a pressure relief valve 37, which is pressed into the opening 35 by plate springs 38 is closed.

When switching off, the switching pin 14 is first from the Contact tulip 11a pulled. This creates an arc between these parts, which if the top of the Switch pin 14 is pulled through the erosion ring 32a of the contact tulip 11a commutates thereon. If so Tip of the switching pin 14, the further erosion ring 32b happens, the other end of the arc commutates this. The arc now connects the two burn rings 32a, b. The switch pin 14 is moved further down until he has released the pressure chamber 25b.

The heating volume 18 is essentially the same as already in connection with the first embodiment described a high pressure built up. The Pinch pressure through the double formation of pressure space and Return channel fully used. Overpressure is in the Usually through the exhaust pipes 34a and 34b, so are dimensioned in such a way that they build up a normal pressure the pressure spaces 25a, b do not prevent in the Exhaust volumes 30a, b derived. If in the pressure chamber 25a for example because of the very great strength of the electricity to be switched off the pressure rises very much, especially a strong one axial pressure surge occurs, as there is in Fig. 2 on the right shown, the pressure relief valve 37, the relief opening 35 free and thus creates additional pressure relief.

In the described embodiment, the exploitation of the Comprehensive arc energy for pressure build-up because of Arc room 16 not directly with an exhaust volume is connected, but only via the pressure spaces 25a, b. It is enclosed on all sides by spaces that build up pressure Contribute, namely the heating volume 18 and the pressure rooms 25a, b. Thanks to the latter with the exhaust volumes 30a, b connecting exhaust pipes 34a, b and the pressure relief valve 37 there is still no risk of overload.

The one shown in Figures 3a and 3b Burn-up switching arrangement according to the third embodiment of the circuit breaker according to the invention corresponds in essential, in particular in the structure and arrangement of Contact pieces, those according to the first embodiment. As for the equally trained parts of the Burn-up switching arrangement is concerned accordingly referred to the description there. The remaining parts of the Circuit breakers can according to the first Embodiment to be formed.

The main difference is that the cap 27 is continuously trained in the center and there is none Exhaust opening has. The pressure chamber 25 is similar for this as with the switch according to the second embodiment in this case five evenly distributed over the circumference Exhaust pipes 34 connected to the exhaust volume 30. In addition, each is preferably in the same number as that Exhaust pipes 34 arranged between them, according to relief openings 39 widening on the outside in the cap 27 provided the return duct 28 with the exhaust volume 30 connect. They are located in the area where the Return channel 28 from the radial in the axial direction bends and in each case in a similar manner to the switch according to the second embodiment by a flattened conical piston 40 of a pressure relief valve 41 closed, which of disc springs 42 in the Relief opening 39 is pressed.

Pressure surges that occur when the device is switched off are a central bulge 43 of the cap 27 radially deflected outside into the return duct 28. Will the pressure there too high, the pressure relief valves open for relief 41.

The specified embodiments can be in many Terms are modified without changing the scope of the Invention would leave. So z. B. heating volume and Return channel can be divided radially. Training the Switch pieces, the blowing device and the arc room can be modified very largely.

Reference list

1

casing

2nd

Shift axis

3rd

upper housing part

4th

lower housing part

5

middle housing part

6

Upper fixed nominal current contact

7

lower fixed nominal current contact

8th

Movable nominal current contact

9

partition wall

10th

Burn-up switching arrangement

11; 11a, 11b

Contact tulip

12th

jet

13

Sliding guide

14

Switching pin

15

partition wall

16

Arcing room

17th

Electric arc

18th

Heating volume

19th

Blow slot

20th

wall

21

Blow cylinder

22

Blowgun

23

Blow channel

24th

check valve

25; 25a, 25b

Pressure room

26; 26a, 26b

cover

27; 27a, 27b

cap

28; 28a, 28b

Return channel

29

check valve

30; 30a, 30b

Exhaust volume

30 '

further exhaust volume

31

Exhaust opening

32a, 32b

Burn ring

33a, 33b

ring

34; 34a, 34b

Exhaust pipe

35

Relief opening

36

piston

37

Pressure relief valve

38

Belleville washers

39

Relief opening

40

piston

41

Pressure relief valve

42

Belleville washers

43

bulge

Claims (28)

Circuit breaker with at least one erosion switching arrangement (10), which has a first contact piece and one relative to it along a switching axis (2) between a switch-on position in which it touches the first switch piece and a switch-off position in which it moves in the axial direction by a switching distance is at a distance and releases an arc chamber (16) lying between the switching pieces, comprises a switchable second switching piece, with a heating volume (18) connected to the arc space (16), with at least one exhaust, via which the arc space (16) with at least one exhaust volume ( 30; 30a, 30b) and at least one pressure chamber (25; 25a, 25b) axially connected to the arc space (16) and connected to the heating volume (18), characterized in that each pressure space (25; 25a, 25b ) an exhaust goes out, which connects it with an exhaust volume (30; 30a, 30b). Circuit breaker according to Claim 1, characterized in that the first switching piece forms an opening surrounding the switching axis (2), into which the second switching piece, touching the edge of the opening, projects in the switched-on position and which, in the switched-off position, the pressure chamber (25; 25a, 25b) connects to the arc chamber (16). Circuit breaker according to claim 2, characterized in that the first switching piece comprises a fixed contact tulip (11; 11a) with a plurality of contact fingers. Circuit breaker according to claim 3, characterized in that the contact fingers are directed at least obliquely against the switching axis (2) over at least part of their length. Circuit breaker according to one of claims 1 to 4, characterized in that the first switching element comprises a fixed erosion ring (32a) arranged upstream of its other parts in the arc space (16). Circuit breaker according to one of claims 1 to 5, characterized in that the second switching piece comprises a movable switching pin (14). Circuit breaker according to claim 6, characterized in that the second switching piece comprises a fixed sliding tulip (11b) which surrounds the switching pin (14) and is in electrically conductive contact with it at least in the closed position. Circuit breaker according to claim 6 or 7, characterized in that the second switching piece comprises a fixed erosion ring (32b) which surrounds the switching pin (14) in the switched-on position and is arranged upstream thereof in the arcing chamber (16). Circuit breaker according to one of Claims 1 to 7, characterized in that it comprises a nozzle (12) made of electrically insulating material and arranged in the arc space (16). Circuit breaker according to one of claims 1 to 9, characterized in that the heating volume (18) surrounds the arc space (16) in a ring and each has at least one blowing opening directed against the same. Circuit breaker according to claim 10, characterized in that the heating volume (18) surrounds the arc chamber (16) undivided and the blow opening is designed as a circumferential blow slot (19). Circuit breaker according to claims 5, 8 and 11, characterized in that the blow slot (19) lies between the erosion ring (32a) of the first switching element and the erosion ring (32b) of the second switching element. Circuit breaker according to one of Claims 1 to 12, characterized in that the connection of the pressure chamber (25; 25a, 25b) to the heating volume (18) is established via at least one return duct (28; 28a, 28b), which is only at least approximately radially aligned leads outside and then bends towards the heating volume (18) in an at least approximately axial direction. Circuit breaker according to Claim 13, characterized in that the cross section of the return duct (28; 28a, 28b) increases at least over part of the distance from the pressure chamber (25; 25a, 25b) to the heating volume (18). Circuit breaker according to Claim 13 or 14, characterized in that the cross section of the part of the return duct (28; 28a, 28b) adjoining the pressure chamber (25; 25a, 25b) increases. Circuit breaker according to one of claims 13 to 15, characterized in that the return channel (28; 28a, 28b) is essentially rotationally symmetrical with respect to the switching axis (2). Circuit breaker according to one of claims 13 to 16, characterized in that the return duct (28; 28a, 28b) has a check valve (29; 29a, 29b). Circuit breaker according to one of claims 1 to 17, characterized in that the connection of the arc chamber (16) with the at least one exhaust volume (30; 30a, 30b) is established only via the at least one pressure chamber (25; 25a, 25b). Circuit breaker according to one of Claims 1 to 18, characterized in that it has two pressure chambers (25a, 25b) which are separated from one another by the arc chamber (16) and are each connected to the heating volume (18). Circuit breaker according to one of claims 1 to 19, characterized in that the exhaust of at least one pressure chamber (25; 25a, 25b) comprises a plurality of eccentrically arranged exhaust pipes (34; 34a, 34b) connecting the same to the exhaust volume (30; 30a, 30b). Circuit breaker according to one of claims 1 to 20, characterized in that the exhaust of at least one pressure chamber (25) comprises a central axial exhaust opening (31) at the opposite end of the arc chamber (16). Circuit breaker according to one of claims 1 to 21, characterized in that the pressure chamber (25; 25a) is connected to the exhaust volume (30; 30a) by at least one pressure relief valve (37; 41). Circuit breaker according to Claim 22, characterized in that an overpressure valve (37) is arranged centrally at the end of the pressure chamber (25a) opposite the arc chamber (16). Circuit breaker according to Claim 13 and Claim 22 or 23, characterized in that a plurality of pressure relief valves (41) are arranged on the outside of the return duct (28). Circuit breaker according to one of claims 1 to 24, characterized in that at least part of the pressure chamber (25; 25a, 25b) and optionally the return duct (28; 28a, 28b) are lined with a plastic material. Circuit breaker according to claim 25, characterized in that the plastic material is polyoxymethylene, polyethylene, polypropylene, plexiglass, polytetrafluoroethylene or melamine resin. Circuit breaker according to one of Claims 1 to 25, characterized in that it has at least one blow cylinder (21) with a blow piston (22) which is actuated when switched off and which is connected to the heating volume (18). Circuit breaker according to one of claims 1 to 27, characterized in that a rated current switching arrangement is provided in parallel with the erosion switching arrangement (10).

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