EP1811537B1 - Interrupting chamber for a gas insulated circuit breaker - Google Patents

Abstract

The chamber has a contact arrangement held in a housing and arranged with two electric arc contacts (3, 4) that are adjustable along a symmetrical axis relative to each other. A flow space is guided at the electric arc contact (3). A compression device is guided with a fixed piston by a tubular contact, where the piston is formed in a ring shape. The piston is held at a wall of the flow space, where the wall and the piston are a part of a mounting unit (27) that is fastened at the housing.

Description

TECHNICAL AREA

The present invention relates to a switching chamber for a gas-insulated high-voltage switch according to the preamble of claim 1. The invention also relates to a switch with such a switching chamber.

A switching chamber of the aforementioned type is generally used in gas-insulated circuit breakers in the voltage range of about 70 kV and for turn-off of more than 10 kA and is with an arc extinguishing properties having insulating gas, such as based on sulfur hexafluoride and / or nitrogen and / or carbon dioxide, in the generally filled up to a few bar pressure. If these circuit breakers cause a large short-circuit current, then a considerable amount of hot arc gas is released explosively by the forming switching arc, which can be used to extinguish the switching arc. If this gas exits the switching chamber, a gas chamber surrounding the switching chamber as well as insulators involved in the construction and in the mounting of the chamber can be subjected to excessive dielectric stress. Therefore, the hot arc gases are previously cooled in dielectrically uncritical spaces of the switching chamber. When switching small currents, the accumulating amount of arc gas to extinguish the switching arc is generally not sufficient. Therefore, a Blashilfe is provided for generating extinguishing gas, which is generally designed as a piston-cylinder compression device.

STATE OF THE ART

A switching chamber of the type mentioned is described in US 4,467,158 A and has an insulating gas-filled metal container 21, in which a Interrupter unit with a contact arrangement and a piston-cylinder compression device 22 is arranged. The cylinder 28 of the compression device is designed to be movable and contains a coaxial arrangement of a drive 30 axially displaceable, hollow cylindrical contact carrier 29 to which an arcing contact assembly 41 of the contact assembly is mounted. In a switching operation of the contact carrier 29 slides with its lateral surface on the acting as a guide element of a sliding guide of the carrier 29 inner wall of an annular piston 27 of the compression device. Hereby formed, hot arc gas expands through the contact carrier 29 in a discharge space. The piston 27 and acting as a wall of the outflow space support member 24 of the piston are designed as a mounting unit. This mounting unit is attached to a supported on a hollow insulator 25 hollow power connector 26. At the power connector 26 and the support member 24 coaxially surrounding wall is mounted, which limits an arranged between the support member 24 and wall the exhaust chamber of the switching chamber radially outward.

A switching chamber with a discharge chamber is also in EP 1 403 891 A1 described. The outflow chamber surrounds an open tube section of a tubular arc contact of the switching chamber, through which hot arc gas formed by the switching arc when a large short-circuit current is switched off can explode. In the outflow chamber, the exhaust gas arc is calmed. This improves the dielectric properties of the gas. In an exhaust space surrounding the outflow space, the dielectric properties of the gas flowing out of the outflow space are further improved. After leaving the exhaust space, the gas can then be safely guided into a gas space which is highly dielectrically loaded and which surrounds the switching chamber. With such a switching chamber large Ausschaltleistungen can be achieved with small dimensions. For switching small currents, this switching chamber contains a piston-cylinder compression device. In this compression device, compressed quenching gas is formed, with which a low-energy switching arc formed when a small current is turned off is successfully blown.

An in US 4,229,627 A. described switch has two relatively displaceable switching pieces, which are arranged in a filled with insulating gas, in particular SF ₆ , housing. The housing is formed by an insulating tube and two gas-tight attached to the end faces of the insulating end plates. At the end plate, the switching piece is held stationary, whereas a designed as a pipe contact carrier of the switching piece is guided in a gas-tight manner through the end plate into the housing. Inside the housing there is provided a mounting unit fixed to the end plate, which has a carrier designed as a hollow cylinder and a piston of a compression device held stationary on the carrier for producing compressed extinguishing gas. The carrier encloses a coaxially guided around the hollow contact carrier space which communicates via openings in the contact carrier with the interior of the contact carrier and via openings in the carrier with the insulating gas-filled switching chamber housing. The contact carrier is passed through the piston and carries at a guided by the piston, free end a hollow arcing contact, which carries a foot point of a switching arc when opening the switch.

Hot arc gas formed by the arc when opening flows via the hollow arcing contact, the contact carrier and the openings provided in the contact carrier first into the space enclosed by the contact carrier and from there via the openings provided in the carrier directly into the interior of the housing. The arc gas passing from the space enclosed by the contact carrier is in this case led directly to the insulating tube of the switching chamber housing which is heavily loaded with dielectric.

US 4 182 942 A shows a gas-insulated high voltage switch, in which an interrupter unit is arranged with a contact arrangement and a piston-cylinder compression device in an insulating gas-filled metal container. In this prior art, hot exhaust gas leaving a hollow arcing contact is cooled in an outflow space and subsequently ejected into the metal container via openings in a wall bounding the outflow space.

An in EP 0 039 096 A described Blaskolbenschalter has a compression device with a compression space which is delimited by a movable blow cylinder and a ring-shaped blow piston. Through the blow piston through a tubular formed arcing contact of the switch is guided. The blow piston is fixedly held at a free end of a support tube, the piston holding end of which is tapered. The piston therefore has a circular disk-shaped annular body with two exposed end faces. In this annular body, a check valve is arranged, which connects the compression space with the compression space of a further compression device. A seal prevents hot exhaust gas passing from the arcing contact from reaching the check valve.

EP 0 398 213 A shows a Blaskolbenschalter with a arranged in a insulating gas-filled volume switching unit. When switching off, hot exhaust gas is conducted from a tubular arcing contact of the switching unit into a discharge space surrounding this contact in the region of outlet openings, from which it flows directly into the volume.

On off US 4 048 456 A known Blaskolbenschalter has a displaceable by a drive along an axis arcing contact, which is guided in two offset along the axis arranged slide bearings.

PRESENTATION OF THE INVENTION

The invention, as indicated in the claims, the object is to provide a switching chamber of the type mentioned, which is characterized by a simple structure and can be manufactured inexpensively.

In the switching chamber according to the invention, an assembly unit comprises two mold parts detachably interconnected by mating, of which the first forms the wall of a discharge space and the piston of a compression device and the second a second of two Guides wearing a sliding guide. This makes it possible that fixed parts of the switching chamber, such as the piston, the outflow space and the two guide elements of the sliding guide, are integrated into a single mounting unit. The assembly unit is prefabricated in production technology advantageously by plugging together two mold parts and is fixed in the assembly of the switching chamber in a single assembly step to a flange of a housing of the switching chamber. Characterized in that the mounting unit has two molded parts joined together by plugging, certain functional parts, such as the piston, can be molded into the mounting unit in a cost-efficient casting process and without machining.

In a preferred embodiment of the switching chamber according to the invention, the second guide element is formed from an electrically conductive bearing metal and serves to transmit power from the mounting unit to the tubular arcing contact. It is thus additionally ensured the function of power transmission from the mounting unit to the arcing contact.

If the mounting unit carries a seal which shields the second guide element from the discharge space, then the second guide element of the sliding guide is protected from hot exhaust gas.

A secure mounting of the mounting unit in the switching chamber is ensured when the first molded part is placed on a molded-on switching chamber housing the switching chamber or rigidly connected to this flange and connected non-positively with the flange. A particularly good adhesion is achieved when the second mold part is clamped by means of a screw connection between the flange and the first mold part.

Advantageously, the piston is held on a tapered portion of the wall and carries a control valve which is disposed in an area adjacent to the exhaust space outer portion of the piston. The closing of the switching chamber, the circulation of the provided in the switching chamber insulating gas favoring control valve is then deprived of the direct effect of the exhaust gas.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to drawings, an embodiment of the invention will be explained in more detail below. In this case, the single figure shows a plan view of a guided along an axis section through a portion of a switching chamber according to the invention, in which the above half of the axis of an axially symmetric contact arrangement of the switching chamber is closed and the half located below the axis opened during a turn-off becomes.

WAYS FOR CARRYING OUT THE INVENTION

The switching chamber shown in the single figure is part of a high voltage circuit breaker and can be used for example in a high voltage network with a rated voltage of 250 kV. This chamber contains a filled with a compressed insulating gas, such as based on sulfur hexafluoride or a sulfur hexafluoride gas mixture, filled and largely tubular housing 1 and a received from the switching chamber housing 1 and largely axially symmetrical contact arrangement 2. The contact assembly 2 has two arcing contacts 3, 4 of which the arcing contact 3 is arranged to be movable along the axis of symmetry 5 and the arcing contact 4 is held stationary in the housing 1. The contact 4 does not have to necessarily fixed, it may also be designed to be movable. The two arcing contacts are coaxially covered by an insulating nozzle 6. The reference numerals 7 and 8 designate two tubular rated current contacts, one of which, namely 7, is rigidly and electrically conductively connected to the arcing contact 3 by means of a cylinder bottom 9. The other rated current contact, namely 8, is electrically conductively connected to the arcing contact 4 via an unillustrated connecting element.

The rated current contact 7 forms the outer jacket of an insulating gas-filled, hollow cylinder-shaped volume, the inner wall of the arc contact 3, the right end wall of the insulating 6 and the left end wall of a fixed, annular piston 10 of a compression device 11 is formed. The volume is divided by the cylinder bottom 9 in a constant volume containing heating volume 12 and a variable volume containing compression volume 13. When switched off, the heating volume 12 communicates with a switching arc receiving arc zone 14 (lower half of the figure). The compression volume 13 communicates via a non-illustrated in the cylinder bottom 9, not shown check valve with the heating volume 12 as soon as the pressure in the compression volume 13 is higher than in the heating volume 12.

The piston 10 is held on an outer wall 15 of a toroidal outflow chamber 16. The holding force is obviously achieved in that the piston 10 and the wall 15 are integrated into a production-technically advantageous molding 17. But the holding force can also be achieved by a connecting element, such as a screw or press connection. In any case, the piston 10 carries in coaxial arrangement on its inside at least one annular guide member 18 and on its lateral surface at least one annular seal 19. The outflow chamber 16 has constant volume and is through the wall 15 to the outside and through the arcing contact 3 and a molding 20 of electrically conductive material bounded inside. To the left, the outflow space 16 is largely limited by the mold parts 17, 20 and to the right by a tapered portion 21 of the wall 15 and a guide member 18 holding portion of the piston 10. The outflow chamber 16 surrounds the tubular arcing contact 3 in a contact tube section, in the at least one gas passage 22 is formed in the pipe wall. In the wall 15 at least one opening 23 is formed, through which the outflow chamber 16 communicates with an exhaust space 24.

The exhaust space is limited by the switching chamber housing 1 to the outside and includes the outflow chamber 16 completely. To the outside, it communicates via openings 34 with a volume of gas filled with insulating gas, which is heavily loaded with dielectric during operation of a switch containing the switching chamber and contains dielectrically highly stressed insulators. To the right of the exhaust space 24 is limited by one of the leadership of the rated current contact 7 annular approach to the switching chamber housing 1 and to the left by a molded on Schaltkammergehäuse 1 or rigidly attached to this with not shown connecting means flange 25. The flange is on a the switching chamber housing 1 supporting Insulator 26 supported and carries on the side facing away from the support insulator 26 side of a mounting unit 27, which is fixed by means of a screw 28 on the flange 25.

The mounting unit 27 includes the two mold parts 17 and 20 in a coaxial arrangement, wherein the molded part 20 is arranged inside and the molded part 17 outside. The molded part 20 carries an annular guide element 29, which is optionally formed from a highly electrically conductive bearing metal. The guide element 29 forms with the arcing contact 3 a sliding guide. If the guide element 29 is designed to conduct current, then it can also ensure the current transition from the molded part 20 or the mounting unit 27 to the arcing contact 3. The molded part 20 also carries a seal 30, which prevents hot exhaust gas located in the outflow chamber 16 from being able to act directly on the guide element 29 through a narrow annular gap which is always present between the arcing contact 3 and the molded part 20. Optionally, a similar seal for protecting the guide member 18 may also be attached to the inside of the piston 10. As can be seen, the molded part 20 includes an outer flange 31 and the molded part 17 has an inner flange 32 which is offset in the axial direction to the right with respect to its end face facing the flange 25. The molded part 17 also has at its left end side female thread, which are intended to receive unspecified screws of the screw 28.

When the contact arrangement 2 of the switching chamber (upper half of the figure) is closed, the path of a large short-circuit current conducted in the switching chamber generally extends from a first power connection, not shown, via an electrically conductive section of the switch housing 1, a sliding contact 1 'held inside this section. which at the same time as a guide element of a sliding guide for the cylinder of the compression device 11, respectively. the rated current contact 7 acts, and the rated current contact 8 to a likewise not apparent second power connection. When switching off the current of the arcing contact 3 is moved by a switch drive, not shown, to the left and initially the rated current contacts 7, 8 are opened. The current commutates from the rated current contacts in a current path containing the two arcing contacts 3, 4, which now runs from the rated current contact 7, the cylinder bottom 9, the arcing contact 3 and the arcing contact 4 to the second power connection. After the separation of the arcing contacts, a switching arc is formed, which generates hot arc gas of high pressure in the arc zone 14 (lower half of the figure). Part of the hot arc gas escapes as exhaust gas into the hollow arcing contact 3 and flows through the gas passage 22 into the outflow space 16 where pressure, temperature, flow velocity and / or flow direction of the exhaust gas are changed by appropriately guiding and holding the gas flow. Gas exiting via the opening 23 into the exhaust space 24 then already has improved dielectric properties. In the exhaust chamber 24, the escaping gas further regenerates and then after leaving the exhaust space 24 via the openings 34 in the surrounding gas space to a quality sufficient to the dielectrically heavily loaded gas space and provided in the gas space and the action of the gas and the action strong electrical fields exposed parts, such as the support insulator 26 or an integrated into the switching chamber housing quenching chamber insulator to avoid electrical flashovers.

Alternatively, the current path with closed contact assembly 2 from the first power connection, not shown, via the flange 25, the mounting unit 27, the now formed as a sliding contact guide member 29, the Arc contact 3, the cylinder bottom 9 and the rated current contacts 7, 8 extend to the second power connection.

When switching off a small short-circuit current, the extinguishing gas formed in the heating volume 12 may not be sufficient for successful blowing of the switching arc. For blowing, then extinguishing gas from the compression volume 13 is used, which was generated by compression in the compression device 11 when turned off.

• das geeignete Führen und Halten des aus dem Lichtbogenkontakt 3 ausströmenden Auspuffgases durch die den Auspuffraum 16 begrenzende Wand 15,
• das Abgrenzen und Abdichten des Kompressionsvolumens 13 gegen den Auspuffraum 24 durch den Kolben 10 und die am Kolben gehaltene Dichtung 19,
• das Führen des Lichtbogenkontakts 3 mit Hilfe der Führungselemente 18 und 29,
• der Schutz des Führungselements 29 vor dem heissen Auspuffgas durch die Dichtung 30, und
• gegebenenfalls das Führen von Strom mit Hilfe des gegebenenfalls als elektrischer Gleitkontakt ausgeführten, zwischen Montageeinheit 27 und Lichtbogenkontakt 3 angeordneten Führungselements 29.

The fact that the piston 10 is held on the wall 15, a single mounting unit 27 can take over several of the incurred during operation of the switching chamber functions for which otherwise several mounting units are required. In particular, these features include:

• the suitable guiding and holding of the exhaust gas flowing out of the arcing contact 3 through the wall 15 bounding the exhaust space 16,
• the delimiting and sealing of the compression volume 13 against the exhaust space 24 by the piston 10 and the seal 19 held on the piston,
• guiding the arcing contact 3 by means of the guide elements 18 and 29,
• the protection of the guide member 29 from the hot exhaust gas through the seal 30, and
• if necessary, carrying current with the help of optionally designed as an electrical sliding contact between the assembly unit 27 and arcing contact 3 arranged guide member 29th

Another function is performed by the mounting unit by the support of a control valve 33 which is arranged on the piston 10 and controls the supply of insulating gas into the compression volume 13 when the contact arrangement 2 is closed. Because the wall 15 has a tapered section 21, the valve 33 can be arranged in an outer section of the piston 10 adjacent to the exhaust space 24 and not to the discharge space 16 become. The valve 33 is then no longer exposed to the direct action of flowing from the arcing contact 3, hot exhaust gas.

When mounting the switching chamber, the two mold parts 17 and 20 are plugged together and fixed as a mounting unit 27 on the housing flange 25 by means of the screw 28. The thickness of the outer flange 31 is slightly larger than the distance of the inner flange 32 generated by the displacement of the end face of the molding 20. Therefore, the outer flange 31 is clamped in the manufacture of the screw 28 between the flange 25 and inner flange 32 and so is a rigid attachment of the mounting unit 27 reaches the switching chamber housing 1. Before the definitive setting of the mounting member 27, a likewise designed as a mounting unit part of the contact assembly 2, which comprises the arcing contact 3, the cylinder base 9, acting as a cylinder wall rated current contact 7 and the insulating 6, inserted from the right into the switching chamber housing 1 and in the from the Figur apparent position can be brought. After installation of the fixed contacts 4 and 8 and further to the right adjoining elements, such as another exhaust chamber, and after attaching two power connectors on the housing, one of which with the apparent from the figure portion of the switching chamber housing 1 and the other with a connected by this section electrically insulated housing portion, then the switching chamber can be completed.

Characterized in that fixed parts of the contact arrangement 2, such as the piston 10, the outflow space 16, the two guide elements 18 and 29 and the seals 19 and 30 and an optionally provided on the inside of the piston 10 further seal, are integrated in a mounting unit 27, the production of the switching chamber can be simplified. The assembly unit 27 can be prefabricated in production engineering advantageous manner and subsequently arranged in the assembly of the switching chamber in a single assembly step on the flange 25 and fixed after installation and adjustment of a movable parts of the contact arrangement, such as arcing contact 3 and rated current contact 7, comprehensive assembly unit on the flange 25 ,

Due to the fact that the assembly unit 27 has two plug-in mold parts 17 and 20, certain functional parts, such as the piston 10, can be molded into the assembly unit 27 in a cost-efficient casting process. In principle, this is also possible if the mounting unit 27 only contains a shaped body. But then it may be necessary to rework this shaped body by machining.

LIST OF REFERENCE NUMBERS

1

casing

1'

sliding contact

2

Contact configuration

3, 4

Arcing contacts

5

axis

6

insulating

7, 8

Rated current contacts

9

cylinder base

10

piston

11

compression device

12

heating volume

13

compression volume

14

Arc zone

15

wall

16

outflow

17

molding

18

guide element

19

sealing ring

20

molding

21

wall section

22

Gas passage

23

opening

24

exhaust space

25

flange

26

support insulator

27

mounting part

28

screw

29

guide element

30

poetry

31

outer flange

32

inner flange

33

control valve

34

openings

Claims (6)

1. Switching chamber for a gas-insulated high-voltage switch having a housing (1) which is filled with insulating gas,
   having a contact arrangement (2) which is held in the housing (1) and has two arcing contacts (3, 4), which can be moved relative to one another along an axis (5), one (3) of which is tubular,
   a gas passage (22) which is formed in the wall of the tubular arcing contact (3),
   an outlet-flow area (16) which is passed around the tubular arcing contact (3) and has a wall (15) which is held stationary,
   an exhaust area (24) which encloses the outlet-flow area (16) and communicates with the outlet-flow area (16) via an opening (23) which is provided in the wall (15) of the outlet-flow area (16),
   a sliding guide for the tubular arcing contact (3), and
   a compression apparatus (11) with a stationary, annular piston (10), through which the tubular contact (3) is passed,
   wherein the piston (10) is held on the wall (15) of the outlet-flow area (16) and is fitted with a first guide element (18) of the sliding guide on an inner face, facing the tubular arcing contact (3), and wherein the wall (15) and the piston (10) are part of a mounting unit (27) which is attached to the switching chamber housing (1),
   characterized in that the mounting unit (27) has two mouldings (17, 20) which are detachably connected to one another by plugging them together, the first (17) of which forms the wall (15) of the outlet-flow area (16) and the piston (10) of the compression apparatus (11), and the second (20) of which is fitted with a second guide element (29) of the sliding guide.
2. Switching chamber according to Claim 1, characterized in that the second guide element (29) is formed from an electrically highly conductive bearing metal and is used to transmit current from the mounting unit (27) to the tubular arcing contact (3).
3. Switching chamber according to one of Claims 1 or 2, characterized in that the mounting unit (27) is fitted with a seal (30) which screens the second guide element (29) from the outlet-flow area (16).
4. Switching chamber according to one of Claims 1 to 3, characterized in that at least one first (17) of the two mouldings (17, 20) is placed on a flange (25), which is integrally formed on the housing (1) of the switching chamber or is rigidly connected to it, and is connected to the flange with a force fit.
5. Switching chamber according to Claim 4, characterized in that the second moulding (20) is clamped between the flange (25) and the first moulding (17), with the aid of a screw connection (28).
6. Switching chamber according to one of Claims 1 to 5, characterized in that the piston (10) is held on a tapered section (21) of the wall (15) and is fitted with a control valve (33) which is arranged in an outer section of the piston (10), adjacent to the exhaust area (24).

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