CN116195019A

CN116195019A - Improved vacuum switch tube

Info

Publication number: CN116195019A
Application number: CN202180055307.XA
Authority: CN
Inventors: F·格拉斯科夫斯基
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2020-08-14
Filing date: 2021-08-02
Publication date: 2023-05-30
Also published as: EP4176456A1; WO2022033909A1; DE102020210342A1

Abstract

The invention relates to an improved vacuum interrupter for low, medium and high voltage switching devices, to a switching device having such an improved vacuum interrupter and switching device.

Description

Improved vacuum switch tube

Vacuum switching tubes for low, medium and high voltages are known from the prior art, which have at least one fixed contact and a movable contact, which are arranged at least in a tubular structure consisting of an insulator, an end cap and a bellows (Balg) for achieving the movable contact. The vacuum interrupter interrupts the current by moving the movable contact away from the first position, i.e. away from the fixed contact, thereby reaching a separation distance in which the movable contact contacts and thus electrically contacts the fixed contact, which prevents ignition or re-ignition of the arc between the contacts, i.e. between the movable contact and the fixed contact. This separated position of the moving contact and the fixed contact is referred to as a second position. The vacuum interrupter switches the current through the moving contact away from, i.e. close to, the fixed contact from a second position in which the moving contact is separated from and thus electrically insulated from the fixed contact, to a first position in which the moving contact is in contact with and thus electrically contacted with the fixed contact.

Here, low voltage means a voltage range of up to 1kV, medium voltage means a range between 1kV and 52kV, and high voltage means voltages of 52kV and 52kV or more.

Such a vacuum interrupter is known, for example, from DE 38 32 493 A1.

Due to the mechanical and electrical requirements for such vacuum switching tubes, they are expensive to manufacture and are more sensitive than, for example, gas-insulated switches. In particular, conventional vacuum switching tubes require significantly higher contact forces, in particular when short-circuit currents are switched on. This results in a higher risk of the contacts being soldered, bonded together in relation to the fixed contact and the movable contact. The drive of the vacuum interrupter must therefore perform a so-called separation strike in order to ensure separation of the contacts with a high probability. Such separation impact results in a dielectric weak point at the contact.

Disclosure of Invention

The object of the present invention is to eliminate these disadvantages of the prior art and to provide an improved vacuum interrupter.

The above-mentioned technical problem is solved by a vacuum interrupter according to independent claim 1 and a vacuum interrupter from its dependent claims as well as a switching device having one or more such vacuum interrupter and a switching apparatus having one or more such switching devices.

One embodiment relates to a vacuum interrupter for low, medium and high voltage switchgear, having one or more insulators, a moving contact flange, a moving contact lever, a moving contact bushing arrangement and a fixed contact flange, wherein the vacuum interrupter

-a movable contact point is provided for the purpose of,

having mating contacts for moving contacts

a) The moving contact has a convex geometry on the side facing the mating contact and the mating contact has a concave geometry on the side facing the moving contact, or

b) The moving contact has a concave geometry on the side facing the mating contact, and the mating contact has a convex geometry on the side facing the moving contact,

wherein the respective concave geometry and the respective convex geometry each have mutually cooperating contact areas, such that in the closed switch position, i.e. the first position, the contact areas of the convex geometry and the concave geometry are in surface contact, in particular the mutually contacting surfaces are configured complementarily to each other and allow a current flow with a low resistance. In this case, the respective contact areas do not have surfaces which extend only perpendicularly to the symmetry axis of the vacuum interrupter, because of the convex and concave geometry of the respective contacts (i.e. the moving contact and the mating contact).

The contact areas of the concave geometry are arranged in grooves formed by the concave geometry, into which the contact areas of the convex geometry are inserted when the contact areas are in contact with each other. Thus, the contact areas of the concave geometry and the convex geometry are arranged within the concave geometry in the first position. With this arrangement, when the switch is shifted from the second position to the first position, i.e. when the switch is turned on, the contact with the convex geometry is centered on the concave geometry, i.e. the moving contact is centered on the mating contact or the mating contact is centered on the moving contact, when the switch is shifted from the separated position to the closed position, in which an electrical contact is made.

Furthermore, when switching on, i.e. when switching from the second position to the first position, in particular when switching on a short-circuit current, the electromagnetically repulsive forces, in particular the hall forces (repulsive Holm force, repulsive hall forces), act perpendicularly to the direction of travel, i.e. the direction of movement of the moving contact, which is parallel to the axis of symmetry of the vacuum interrupter, or at an acute angle perpendicularly to the direction of travel. This reduces the contact pressure required for closing the contacts, i.e. the moving contacts and the mating contacts, which here replace the fixed contacts.

Furthermore, the arrangement of the contact surfaces at the convex geometry and the concave geometry results in shearing forces during the split contact welding and thus in reduced demands on the switching drive, in particular with respect to the force/energy requirements for the drive of the vacuum interrupter. The reduced force/energy requirements for the driving of the vacuum interrupter are also due to the reduced requirements for the separation impact.

Preferably, the moving contact sleeve device is a moving contact bellows, in particular a folded tube (Faltenbalg) or a bellows (wellebag). Alternatively, the moving contact sleeve arrangement may also be an elastomer-sealed linear sleeve or a sleeve sealed with liquid metal.

It is also preferred that the moving contact and/or the mating contact are formed of or have copper and that the contact area at the moving contact and/or the mating contact is formed of a harder and/or more arc resistant material than copper. This increases the contact area and thus the stability and the service life of the vacuum interrupter.

Particularly preferred are alloys containing copper and chromium made of harder and/or more arc resistant materials. It is also preferred that the alloy contains copper and chromium but no carbon, i.e. less than 0.1%, preferably less than 0.01% carbon.

Alternatively, other electrically conductive contact materials and combinations/alloys thereof are also possible.

It is also preferred that the mating contact and the moving contact are partially or entirely coated or otherwise covered with a copper-chromium alloy.

It is particularly preferred that in addition to the contact areas, the staggered areas of the moving contact and mating contact, in particular the convex geometry and the concave geometry, are also coated or otherwise covered with a copper-chromium alloy.

It is also preferred that the contact area is formed by one or more solid members and/or coatings of the moving contact and/or the mating contact. In other words, the contact area may consist of one or more solid members, or may consist of one or more applied layers or a combination of applied layers and solid members. In addition to the function of increasing stability/tolerance under switching conditions, in particular in the event of an arc, the applied layer can in particular achieve a better connection between the respective convex or concave geometry and the solid component or other layer.

Furthermore, it is preferred that the contact area of the moving contact and/or the mating contact is designed annularly. The annular design makes it possible for as small a component of the electromagnetic repulsive force that occurs to act parallel to the symmetry axis of the vacuum interrupter.

It is also preferred that the concave geometry is designed as a pot/bowl, wherein the side walls of the pot/bowl have an angle of 0 ° to 30 °, in particular an angle of 5 ° to 15 °, with respect to the symmetry axis of the vacuum interrupter, and the bottom region of the concave geometry has an angle of 90 °, i.e. a right angle, with respect to the symmetry axis of the vacuum interrupter. The associated convex geometry has a partially complementary or complementary shape relative to the concave geometry. Particularly preferably, the contact region is designed in the form of a ring, and the contact region, i.e. the surface of the contact region which contacts in the first position, has an angle of 0 ° to 30 °, in particular an angle of 5 ° to 15 °, with respect to the symmetry axis of the vacuum interrupter.

It is also preferred that the first and second regions,

a) The convex geometry of the moving contact on the side facing the mating contact is embodied as a truncated cone and the concave geometry of the mating contact on the side facing the moving contact is embodied as a bowl, or

b) The convex geometry of the mating contact on the side facing the moving contact is embodied as a truncated cone and the concave geometry of the moving contact on the side facing the mating contact is embodied as a bowl.

This also achieves evaporation protection of the insulation, in particular of the ceramic, for the vacuum interrupter, since in such a configuration, in the concave configuration, i.e. in the bowl configuration, the insulation is closed in the bowl. The arc occurring in the concave structure, i.e. bowl-shape, is well shielded when switched off.

If the moving contact is embodied as a truncated cone, the mass to be moved is reduced, which has a favorable effect on the drive design and causes a more favorable bouncing behavior (prelllverhalten) due to the possibly lower required drive energy. An alternative embodiment of the moving contact in the form of a bowl has the advantage that the moving contact bellows is additionally protected from flashovers (electrical flashovers) and arc reaction products by the bowl shape.

It is also preferred that the contact area at the moving contact and/or the mating contact is designed linearly, i.e. straight. The straight extension of the contact regions (in the regions respectively provided for contact with the other contact region) allows for a simple manufacture and design of the contact regions with well predictable electrical properties and electric field distribution.

In this case, the contact region preferably has an angle of between 1 ° and 30 °, preferably between 5 ° and 30 °, in particular between 5 ° and 15 °, with respect to the symmetry axis of the vacuum interrupter.

It is particularly preferred that the contact region extends linearly in two or three parts, i.e. in two or three sections, wherein the angle between the respective linear section and the symmetry axis of the vacuum interrupter is between 5 ° and 30 °, in particular between 5 ° and 15 °.

It is furthermore preferred that the first angle of the wall of the concave geometry with respect to the axis of symmetry between the contact region and the opening edge of the concave geometry is greater than the second angle of the contact region with respect to the axis of symmetry.

The distance between the contact area of the moving contact and the wall of the mating contact, which has a varying angle, is thereby greater than if the implementation has no varying angle, in particular without creating an area with too strong an electric field strength.

It is also preferred that the angle is continuously or continuously changed over a constant angular range, wherein the bottom region preferably forms a right angle with the symmetry axis of the vacuum interrupter in the region of the symmetry axis of the vacuum interrupter, and the angle to the contact region of the concave geometry becomes smaller, and the angle from the bottom region to the contact region further decreases, or the angle to the symmetry axis of the vacuum interrupter increases again.

Particularly preferably, the opening edges of the concave geometry are rounded. The rounding of the opening edges of the concave geometry makes it possible to avoid field peaks, in particular in the edge structure.

Also preferably, the insulator is a monolithic ceramic. Thus, a low-cost implementation of the vacuum interrupter is possible.

Also preferably, the insulator is a multipart ceramic. This allows for a field-optimized construction of the vacuum interrupter.

It is particularly preferred that between the first ceramic part and the second ceramic part, a metal region is arranged around the arc region between the moving contact and the mating contact. The ceramic components, i.e. the first ceramic component and the second ceramic component, and the other ceramic components (if present) are thereby protected from stronger evaporation in the arc region.

Preferably, a bellows shield (140) is disposed between the moving contact bellows (129) and the moving contact (126).

It is also preferred that the bellows shield substantially replicates the geometry of the moving contact bellows end to be shielded.

Furthermore, it is also preferred that the bellows shield extends radially beyond the moving contact bellows end. Optimal shielding of the bellows from metal vapors and metal droplets from arcing events is thereby achieved, as well as optimal field control.

It is also preferred that the vacuum interrupter is designed to be able to be operated or to be operated in an overpressure environment, in particular in an overpressure environment of a gas-insulated switchgear. In particular, high voltage levels, in particular medium, high and extra high voltages, can thus also be achieved. Thus, vacuum switching tubes are particularly suitable for SF6 (sulfur hexafluoride) and for SF 6-free gas-insulated switching devices. Operation in an overpressure environment means technical features such as a more stable bellows implementation and/or an efficient derivation of the forces of the ceramic.

The vacuum interrupter with the gas-insulated switching device is preferably operated or can be operated with an insulating gas, wherein the insulating gas is a mixture of nitrogen and/or carbon dioxide, or contains nitrogen and/or carbon dioxide, or the insulating gas contains or is formed from an organofluoride. The organofluorides here include fluoroketones and/or fluoroolefins and/or Hydrofluoroolefins (HFOs) and/or fluoronitriles, among others.

It is also preferred that the mating contacts are designed integrally with the fixed contact flange. This allows for a simpler, lower cost manufacture, in particular because no additional connection points, i.e. solder joints, are required. Alternatively, in a two-part embodiment, the mating contact can be preassembled in such a way that the connection is already formed, in particular completely formed, in the case of a sealing weld.

Further embodiments relate to a switching device having one or more vacuum switching tubes according to one or more of the embodiments described above, wherein the switching device has a connection device which is suitable for fixedly or movably connecting the switching device to a switching apparatus.

One embodiment relates to a switching device having at least one switching means according to one or more of the implementations described above.

The invention is explained below by way of example with reference to the accompanying drawings.

Fig. 1 shows a cross-sectional view of a vacuum interrupter according to the prior art.

Fig. 2 shows a cross-section of a vacuum interrupter according to the invention.

Fig. 3 shows a cross-section of a contact system of a vacuum interrupter according to the invention.

Fig. 4 shows a cross-section of a contact system with a contact area with arc-resistant material of a vacuum interrupter according to the invention.

Fig. 5 shows a cross-section of a contact system with a bellows shield of a vacuum interrupter according to the invention.

Fig. 6 shows a schematic diagram of a switching device according to the invention.

Fig. 7 shows a schematic diagram of a switching device according to the invention.

Fig. 1 shows a schematic cross-section of a vacuum interrupter 10 according to the prior art. The vacuum interrupter 10 has a tubular insulator 12. The insulator 12 is made of ceramic. The vacuum interrupter 10 has a moving contact 26 arranged on a moving contact rod 24, and the moving contact rod 24 is arranged on the moving contact flange 14 in a movable and airtight manner by means of a moving contact bellows 28. The moving contact bellows 28 can be arranged here outside the insulator 12 or inside the insulator 12 and/or the moving contact flange 14 (not shown here). The moving contact flange 14 is again connected hermetically to the insulator 12.

The fixed contact 22 is arranged relative to the movable contact 26, and the fixed contact 22 is guided through the fixed contact flange 16 in a gas-tight manner by means of the fixed contact rod 20. The fixed contact flange 16 is connected to the insulator 12 in a gas-tight manner.

Fig. 2 shows a schematic cross-section of an embodiment of a vacuum interrupter 100 according to the invention. The body of the vacuum interrupter 100 is formed here in particular by a tubular insulator 112, a moving contact flange 114 and a fixed contact flange 116. Thus, the vacuum interrupter 100 shown has a tubular shape and thus an axis of symmetry 101. The vacuum interrupter 100 has a movable contact rod 124, which is connected to the movable contact flange 114 in a movable and airtight manner by means of a movable contact bellows 128. A moving contact 126 is arranged at the end of the moving contact rod 124 within the vacuum interrupter 100, wherein the first moving contact bellows end 129 is arranged closer or farther from the moving contact 126, depending on the necessary travel, and the length of the moving contact bellows 128 is selected accordingly. In this example, the moving contact 126 and the moving contact lever 124 are integrally designed. Furthermore, the vacuum interrupter 100 optionally has a guide 115 for the moving contact rod 124, wherein the guide 115 can also be used as a reinforcement for the moving contact flange 114.

The mating contact 122 for the moving contact 126 is designed to be concave, with a concave geometry, while the moving contact 126 is designed to be convex, with a convex geometry.

The concave geometry of mating contact 122 has a bottom region 123. In the closed state of the vacuum interrupter 100 shown, the moving contact 126 does not contact the mating contact 122 with its entire surface, but rather the moving contact 126 and the mating contact 122 only contact in the contact region 132, which produces a low-ohmic electrical contact. In the illustrated embodiment, in the closed state of the vacuum interrupter 100 shown, the moving contact 126 does not contact the concave geometrically shaped bottom region 123 of the mating contact 122.

Fig. 3 shows a section of a schematic cross-section of a contact system, a moving contact 126 and a mating contact 122 of a vacuum interrupter 100 according to the invention focused on an axis of symmetry 101 of the vacuum interrupter 100. Also shown is a first moving contact bellows end 129 of the moving contact bellows 128 shown in fig. 2. In this case, a contact region 134 with a linear wall section is shown as a preferred embodiment at the moving contact 126 and the mating contact 122. The contact region 134 with the linear wall section is designed such that the second angle 105 between the contact region 134 with the linear wall section and the symmetry axis 101 remains unchanged. The wall within the concave geometry of mating contact 122 has an angle with respect to symmetry axis 101 in the region between contact region 134 facing bottom region 123 and bottom region 123, which increases monotonically from contact region 134 to bottom region 123 and preferably forms a right angle with symmetry axis 101 at the lowest point of bottom region 123. The first angle 103 from the contact region 134 to the opening edge 144 increases monotonically in the range between the side of the contact region 134 facing away from the bottom region 123 and the opening edge 144 of the wall 142 of the concave geometry (i.e., the mating contact). Thus, the region of wall 142 of mating contact 122 has a varying first angle 103 therein.

Fig. 4 shows a section of a schematic cross-section of a contact system according to the invention of a vacuum interrupter 100 focused on an axis of symmetry 101 of the vacuum interrupter 100, a moving contact 126 with an optional contact area 136 and a mating contact 122 with an optional contact area 138. Also shown is a first moving contact bellows end 129 of the moving contact bellows 128 shown in fig. 2. As a preferred embodiment, the contact region 136 at the moving contact 126 and the contact region 138 at the mating contact 122 are designed as solid components. Alternatively, the contact region 136 and/or the contact region 138 may also be designed as a coating or as a combination of a coating and a solid component (not shown here).

Fig. 5 shows a section of a schematic cross-section of a contact system, a moving contact 126 and a mating contact 122 of a vacuum interrupter 100 according to the invention focused on an axis of symmetry 101 of the vacuum interrupter 100. Also shown is a first moving contact bellows end 129 of the moving contact bellows 128 shown in fig. 2. As a preferred embodiment, a bellows shield 140 is provided between the moving contact 126 and the first moving contact bellows end 129, which protects the moving contact bellows 128 from metal evaporation and/or hit by metal droplets in the event of an arc, and also serves as a control electrode.

Fig. 6 shows a schematic view of a switching device 5 according to the invention with a housing 6, a drive 7, at least two connecting

devices

8,9 and at least one vacuum interrupter 100 according to the invention. In the illustration shown here, only a vacuum interrupter 100 according to the invention is shown, in an alternative embodiment the switching device is a single-pole switching device 5 having a vacuum interrupter 100 according to the invention and two connecting

devices

8,9, or a three-pole switching device 5 having three vacuum interrupter 100 according to the invention and three by two, i.e. six, connecting

devices

8, 9. Other solutions are also possible, such as two-pole structures or more.

Fig. 7 shows a schematic diagram of a switching device 1 according to the invention with a switching device 5 according to the invention.

List of reference numerals

1 a switching device;

5 a switching device;

6 a housing of the switching device 5;

7, a driver;

8 connection means, in particular pole connections;

9 connection means, in particular pole connections;

10 vacuum switching tubes;

12 an insulator, ceramic;

14. moving the contact flange;

16. a fixed contact flange;

20. a fixed contact rod;

22. a fixed contact;

24. moving the contact bar;

26. a moving contact;

28. moving the contact bellows;

100 vacuum switching tubes;

101 symmetry axis of the vacuum switching tube 100;

103 with respect to the symmetry axis 101;

105 with respect to the symmetry axis 101;

112 insulator, ceramic;

114 moving the contact flange;

115 guides for moving the contacts, reinforcements for moving the contact flanges;

116. a fixed contact flange;

117. a fixed contact flange joint;

122. mating contact

123, in this case mating contact 122

124. Moving the contact bar;

126. a moving contact;

128. moving the contact bellows;

129 first moving contact bellows end;

132 contact areas;

134 a contact area having a linear wall section at the moving contact 126 and the mating contact 122; 136 move the contact area at contact 126;

138 mating contact areas at contacts 122;

140 bellows shield;

142 have walls of mating contact 122 of varying angles;

144 concave geometry opening edge

Claims

1. Vacuum interrupter (100) for low, medium and high voltage switchgears, having one or more insulators (112), moving contact flanges (114), moving contact rods (124), moving contacts (126), moving contact bushing arrangements and fixed contact flanges (116), characterized in that the vacuum interrupter (100)

-having a moving contact (126),

-having a mating contact (122) for the moving contact (126), and

c) The moving contact (126) has a convex geometry on the side facing the mating contact (122) and the mating contact (122) has a concave geometry on the side facing the moving contact (126), or

d) The moving contact (126) has a concave geometry on the side facing the mating contact (122) and the mating contact (122) has a convex geometry on the side facing the moving contact (126),

wherein the respective concave geometry and the respective convex geometry each have mutually cooperating contact areas (132, 134) such that in the closed switch position the contact areas (132, 134) of the convex geometry and the concave geometry are in surface contact and allow a current flow with low resistance.

2. The vacuum interrupter (100) of claim 1 wherein said moving contact sleeve means is a moving contact bellows (128).

3. Vacuum interrupter (100) according to one of the preceding claims, characterized in that the moving contact (126) and/or mating contact (122) are formed of or have copper and the contact areas (132, 134) at the moving contact (126) and/or mating contact (122) are formed of a harder and/or more arc-resistant material than copper.

4. A vacuum interrupter (100) according to claim 3, wherein the contact areas (132, 134) are formed by solid members (136, 138) or coatings of the moving contact (126) and/or mating contact (122).

5. Vacuum interrupter (100) according to claim 4, characterized in that the contact areas (132, 134) of the moving contact (126) and/or the mating contact (122) are designed annularly.

6. Vacuum interrupter (100) according to one of the preceding claims, characterized in that,

c) The convex geometry of the moving contact (126) facing the mating contact (122) side is embodied as a truncated cone shape, and the concave geometry of the mating contact (122) facing the moving contact (126) side is embodied as a bowl shape, or

d) The convex geometry of the mating contact (122) facing the moving contact (126) side is embodied as a truncated cone shape, and the concave geometry of the moving contact (126) facing the mating contact (122) side is embodied as a bowl shape.

7. Vacuum interrupter (100) according to claim 6, characterized in that the contact area (134) at the moving contact (126) and/or mating contact (122) is designed linearly, rectilinearly.

8. Vacuum interrupter (100) according to one of the preceding claims, characterized in that a first angle (103) of the wall of the concave geometry between the contact region (134) and the opening edge (144) of the concave geometry with respect to the symmetry axis (101) is larger than a second angle (105) of the contact region (134) with respect to the symmetry axis (101).

9. Vacuum interrupter (100) according to one of the preceding claims, characterized in that the insulator (112) is a monolithic ceramic (112).

10. Vacuum interrupter (100) according to one of the preceding claims 1 to 8, characterized in that the insulator (112) is a multipart ceramic (112).

11. The vacuum interrupter (100) of claim 10 wherein a metal region is disposed between the first ceramic part and the second ceramic part around an arc region between the moving contact (126) and the mating contact (122).

12. Vacuum interrupter (100) according to one of the preceding claims, characterized in that a bellows shield (140) is arranged between the moving contact bellows (129) and the moving contact (126).

13. Vacuum interrupter (100) according to one of the preceding claims, characterized in that the vacuum interrupter (100) is designed to be operable in an overpressure environment, in particular in an overpressure environment of a gas-insulated switchgear.

14. Switching device (5) with one or more vacuum switching tubes (100) according to any of the preceding claims, wherein the switching device (5) has connection means (8, 9) adapted to fixedly or movably connect the switching device (5) with a switching apparatus.

15. Switching device (1) having at least one switching means (5) according to claim 14.