EP3297013B1 - High voltage switching apparatus and switchgear using a high voltage switching apparatus and method for producing a high voltage switching apparatus - Google Patents

Description

The invention relates to a high-voltage switching device with a vacuum interrupter and a switchgear with a high-voltage switching device. In addition, the invention relates to a method for producing a high-voltage switching device with a vacuum interrupter.

Switchgear with which the electrical energy is distributed is used in networks of electrical power lines. Switchgears have switchgear that create or separate an electrically conductive connection between electrical contacts. In high-voltage or medium-voltage networks, high-voltage switching devices are used which meet the electrical requirements for the high voltages in high-voltage or medium-voltage networks. The voltages of the high-voltage networks are generally over 52 kV and the medium-voltage networks between 1kV and 52kV.

High-voltage switching devices are known which have a vacuum interrupter in which the electrical contacts are arranged. However, switching devices are also known in which the electrical contacts are in a gas atmosphere made of insulating gas, for example SF ₆ . In contrast to chambers filled with insulating gas, the use of vacuum interrupters offers the advantage that load currents and short-circuit currents can be interrupted in a relatively small volume without the risk of hot switching gases being emitted. A particularly long insulation section is required in air-insulated switchgear, which is why these switchgear take up a particularly large amount of space.

Switchgear with a vacuum interrupter are, for example, from the DE 31 12 776 A1 and DE 40 27 723 A1 known. The known vacuum interrupters have an immovable contact element with a contact and a contact element movable in the axial direction of the vacuum interrupter with a contact, which is made up of the vacuum interrupter extends. The conductor parts forming the current path are connected to the contact elements. The movable contact element is actuated by an actuating member which is sealed off from the housing body of the switching device. The actuator can be driven by an electric drive unit.

The DE 27 39 811 A1 describes a high-voltage switching device with a housing body, in which a vacuum switching chamber is provided which has an immovable switching contact element and a switching contact element movable in the axial direction, to which conductor parts forming the current path are connected. The movable switch contact element, which extends out of the vacuum interrupter chamber, is connected via an insulation body to an actuating member which is movable in the axial direction. A cavity filled with an insulation liquid is formed in the housing body, into which the movable switching contact element extends from the vacuum switching chamber.

The invention has for its object to provide a high-voltage switching device that requires the formation of a relatively short insulation path and thus has a more compact structure compared to the prior art. The invention is also based on the object of providing a switchgear assembly which is distinguished by a particularly compact construction. Another object of the invention is to provide a method with which a high-voltage switching device with a particularly compact structure can be produced simply and inexpensively.

According to the invention, these objects are achieved with the features of the independent claims. The dependent claims relate to preferred embodiments of the invention.

The high-voltage switching device according to the invention has a one-part or multi-part housing body in which a vacuum interrupter is provided. The vacuum switching chamber has an immovable switching contact element and a switching contact element movable in the axial direction, the movable switching contact element extending out of the vacuum switching chamber and being connected via an insulation body to an actuating member movable in the axial direction. The conductor parts forming the current path are connected to the immovable switch contact element and the movable switch contact element.

An actuator is understood to mean all means with which the movable switching contact element can be axially displaced in order to close or open the contacts. The actuator can consist of one or more parts. In the high-voltage switching device according to the invention, a cavity filled with an insulation liquid is formed in the housing body, the movable switching contact element extending from the vacuum chamber into the cavity and the actuating member in turn extending from the cavity filled with insulation liquid. The high-voltage switching device is distinguished by the fact that a sealing arrangement that seals the actuating member from the housing body is provided in the cavity filled with insulating liquid. This ensures a safe interruption of the load current and the short-circuit current with a relatively short insulation path. As a result, the high-voltage switching device can have a compact structure.

A sealing arrangement is understood to mean all means with which a liquid-tight seal with respect to the housing body or parts of the housing body can take place. An arrangement of the sealing arrangement within the cavity is understood to mean that at least the parts of the sealing arrangement that form an assembly that is essential for the sealing are arranged within the cavity. This does not exclude that individual parts which are connected to the sealing arrangement cannot also be located outside the cavity, for example they can have an outwardly facing surface.

The high-voltage switching device provides that the sealing arrangement has a bellows which is arranged in the cavity and which surrounds the actuating member which extends from the liquid-filled chamber in order to seal the actuating member with respect to the housing body. Since the bellows is a component of the sealing arrangement that takes up a relatively large amount of space, the switching device has a more compact structure than a switching device in which a bellows for sealing is arranged outside a chamber filled with insulating liquid or an insulating gas. Such a switching device is for example from the DE 31 13 776 A1 known.

The bellows can be connected to earth potential. Since the bellows is not in an air-filled room, but within the chamber filled with insulation liquid, the risk of flashover of parts of the switching device that are at a high potential is reduced. Therefore, the high-voltage switching device can be made compact.

A particularly preferred embodiment provides that the cavity is closed with a cover that is sealed with respect to the housing body, for example with a removable plate, one end piece of the bellows being sealed in a liquid-tight manner with respect to the cover. Closing the cavity with a cover offers advantages for the manufacture of the high-voltage switching device.

Another essential aspect of the invention, which is of independent inventive importance, is that the housing body comprises a plastic body that at least partially surrounds the liquid-filled cavity. The plastic body can consist of one or more plastic elements which are connected to one another.

The plastic body advantageously consists of a plurality of plastic elements which can be produced simply and inexpensively by the injection molding process and then connected to one another. Individual plastic elements can be inserted into one another and / or glued or welded together.

The use of a plastic body not only improves the electrical properties of the switching device, but also simplifies its manufacture. Corners and edges of the live conductor parts of the switching device located within the plastic body or the plastic elements, for example a movable conductor part that is electrically connected to the movable contact element, cause a strongly inhomogeneous electrical field. To improve the electrical properties, the plastic elements can have rounded corners and edges and consist of an electrically conductive plastic, preferably mixed with a conductive material, for example carbon. These plastic elements can have the same potential as the live components. As a result, the electric field becomes more homogeneous to the outside, so that field control takes place.

The housing body preferably comprises a potting body, which at least partially surrounds the vacuum interrupter and the plastic body. Since the plastic elements have the same potential as the live components, the outer shell of the housing body consisting of a casting compound, for example cast resin, is less stressed.

A particularly preferred embodiment of the plastic body comprises a first shell-shaped plastic element and a second shell-shaped plastic element, the conductor parts forming the current path comprising a movable conductor part which is electrically connected to the movable contact element. The movable conductor part is arranged in the cavity and is at least partially enclosed by the first and second plastic elements. In this embodiment, the corners and edges of the plastic body enclosing the movable conductor part or the corners and edges of its plastic elements are rounded and the plastic body or the plastic elements consist of an electrically conductive plastic, so that they can assume the same potential as the movable conductor part.

In a further particularly preferred embodiment, the plastic body comprises a cylindrical plastic element which at least partially surrounds the sealing arrangement. This plastic element is preferably not conductive and therefore cannot carry any potential. The plastic element can ensure the isolation between potential-carrying components and the actuator, which is at ground potential. The plastic element preferably has lamellae, so that the creepage distance is increased.

To simplify the manufacture of the housing body of the switching device in an injection molding process, the plastic body is sealed off from the vacuum interrupter, so that casting resin cannot get into a gap between the plastic body and the vacuum interrupter. Cutting edges are preferably provided on the plastic body, the housing body of the vacuum interrupter chamber, which can consist of metallic or ceramic materials, being at least partially enclosed by a material into which the cutting edges can cut when the components are assembled.

The switchgear according to the invention has one or more switchgear according to the invention.

With the method according to the invention, a high-voltage switching device can be produced simply and inexpensively, in which the movable switching contact element extends out of the vacuum switching chamber into a cavity filled with an insulating liquid. The plastic elements of the plastic body serve, on the one hand, to prevent the potting compound from getting into the volume enclosed by the plastic elements during casting, for example with epoxy resin. This ensures that the components remain movable within the plastic elements. Since pressures greater than 1 bar can occur during casting, the mechanical strength of the plastic elements must be given. In order to prevent cast resin from penetrating at the interfaces of the plastic elements, they can be inserted into one another and / or glued or welded to one another.

For the manufacture of the high-voltage switching device according to the invention, a casting mold is provided which corresponds in shape and dimensions to the contour of the housing body of the switching device. The vacuum interrupter and the plastic body or the plastic elements are introduced into the casting mold. These plastic elements then form part of the casting mold. The shape and dimensions of the plastic elements therefore determine the shape and dimensions of the housing body, in particular of the parts of the housing body in which the vacuum interrupter chamber is located and in which the chamber to be filled with insulation liquid is formed.

Then the space between the wall of the casting mold and the vacuum interrupter and the plastic body is encapsulated with a potting compound to create a encapsulating body enclosing the vacuum interrupter and the plastic body, in which a cavity enclosed by the plastic body remains.

Then the actuating member and the insulating body as well as the sealing arrangement and possibly further components are inserted into the cavity of the switching device and the cavity is filled with the insulating liquid, the cavity being closed with a cover which is sealed off from the potting body or plastic body. The cover is preferably sealed off from the plastic body.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawings.

Fig. 1

ein Ausführungsbeispiel des erfindungsgemäßen Hochspannungs-Schaltgerätes in teilweise geschnittener perspektivischer Darstellung und

Fig. 2

eine Explosionsdarstellung von einzelnen Bauteilen des erfindungsgemäßen Hochspannungs-Schaltgerätes.

Show it:

Fig. 1

an embodiment of the high-voltage switching device according to the invention in a partially sectioned perspective view and

Fig. 2

an exploded view of individual components of the high-voltage switching device according to the invention.

Fig. 1 shows the essential components of the invention of the high-voltage switching device, while Fig. 2 shows only individual components of the switching device in an exploded view. The corresponding parts are provided with the same reference numerals in the figures.

The high-voltage switching device has a housing body 1 consisting of several parts or components, which in the normal installation position has an upper housing half 1A and a lower housing half 1B. In the upper housing half 1A there is a vacuum switching chamber 2 with a cylindrical housing 3, which receives an upper, fixed switching contact element 4 and a lower, movable switching contact element 5. Both switch contact elements 4, 5 have plate-shaped contacts 4A, 5A, which are located within the housing 3 of the vacuum switching chamber 2. By closing or opening the contacts 4A, 5A, the current path closed or interrupted, ie the load current and the short-circuit current are switched.

A chamber 6, which is filled with an insulation liquid, is formed in the lower housing half 1B. The switching contact element 5 which can be displaced in the axial direction of the vacuum switching chamber 2 has a shaft 5B which extends from the vacuum switching chamber into the chamber 6 filled with insulation liquid. The shaft 5B of the movable switching contact element 5 is sealed in a vacuum-tight manner with respect to the housing 3 of the vacuum switching chamber 2 with a sealing arrangement, not shown. The lower end of the shaft 5B is connected via an insulation body 7 to an actuating element 8 which extends from the liquid-filled chamber. By actuating the actuating member 8, the movable switching contact element 5 can be axially displaced, so that the contacts 4A, 5A are closed or opened.

The actuating member 8 has an upper, hollow cylindrical section 8A, which is located in the chamber 6 and a lower, pin-shaped section 8B, which is guided in the cylinder space of the upper section in a longitudinally displaceable manner and extends from the chamber 6. The upper end piece of the lower section 8B is supported on a compression spring 9 in the cylinder space of the upper section 8A. When the lower section 8B is displaced, the upper section 8A also displaces, so that the movable switching contact element 5 is displaced axially. The compression spring 9 serves to dampen the shocks when the actuating member 8 is actuated. The actuating member 8 is driven by a drive unit (not shown) which displaces the lower section 8B in the axial direction.

The actuating member 8 is sealed against the housing body 1 with a sealing arrangement 10 in a liquid-tight manner. The sealing arrangement 10 has a bellows 11, which encloses the upper section 8A of the actuating member 8, the upper end of the bellows 11 being connected in a liquid-tight manner to the upper section 8A of the actuating member 8. The lower end of the bellows 11 is sealed in a liquid-tight manner with respect to the housing body 1. The bellows 11 and the actuator 8 are on Earth potential. On the underside, the housing body 1 has an opening 23 which is closed in a liquid-tight manner by a cover 13.

The liquid-filled chamber 6 has an upper and lower chamber half 6A, 6B in the installed position. In the upper chamber half 6A there is a movable conductor part 12, for example a copper strip, which is connected to the shaft 5B of the movable switch contact element 5. The movable conductor part 12 is electrically connected to further conductor parts 13 which form the current path, but which are only partially shown. The fixed switching contact element 4 is also connected to further only partially shown conductor parts 14, which are also inserted into the housing body 1 or placed on the housing body.

The housing body 1 comprises a potting body 15, which encloses the vacuum switching chamber 2 and the liquid-filled chamber 6. The potting body 1A forms the outer shell of the housing body 1. The potting compound can be an epoxy resin.
A plastic body 16, which is composed of a plurality of plastic elements 16A, 16B, 16C, sits in the casting body 15 in the lower housing half 1B. Fig. 2 shows the plastic elements 16A, 16B, 16C in an exploded view.
The plastic body 16 has an upper, shell-shaped plastic element 16A and a lower, shell-shaped plastic element 16B in the upper chamber half 6A, which enclose the movable conductor part 12, and has a cylindrical plastic element 16C in the lower chamber half 6B, which encloses the bellows 11. The plastic elements 16A, 16B, 16C are designed such that they can be assembled appropriately. They are plugged tightly together and / or glued or welded together. All plastic elements 16A, 16B, 16C have rounded corners or edges.

The two plastic elements 16A, 16B in the upper chamber half 6A consist of an electrically conductive plastic, for example the plastic can be mixed with conductive carbon. Since these plastic elements 16A, 16B can assume the same potential as the movable conductor part 12 or other conductor parts in the chamber, the electrical field becomes more homogeneous to the outside.

The plastic element 16C in the lower chamber half 6B, which is not made of a conductive plastic, cannot carry any potential. This plastic element 6C is used for the safe isolation of live parts in the chamber 6 from the actuating element 8 which is at ground potential. To increase the creepage distance, the plastic element 16C has lamellae 17 on the outside.

The cover 13 of the housing body 1, which closes the liquid-filled chamber 6, is sealed against the cylindrical plastic part 16C with a sealing ring 18 lying between the cover and the plastic part. The method according to the invention for producing the high-voltage switching device is described below.

For the manufacture of the switching device, a casting mold (not shown in the figures) is used, which is designed such that it corresponds to the shape and dimensions of the housing body 1 of the switching device and the shape and dimensions of the vacuum switching chamber 2 and the other components of the switching device. The vacuum interrupter 2 is inserted into the upper half of the casting mold, an interspace 19 remaining between the wall of the casting mold and the vacuum interrupter 2. The plastic body 16 is inserted into the lower half of the casting mold, an intermediate space 20 also remaining between the wall of the casting mold and the plastic body 16. The spaces 19, 20 between the casting mold and the vacuum interrupter or plastic body are then cast with a casting compound, for example with an epoxy resin. The potting body 15 with the chamber 6 to be filled with insulation liquid is thereby created.

The upper plastic element 16A in the upper chamber half 6A has cutting edges 21 on the upper edge, which cut into a coating 3A of the housing 3 of the vacuum interrupter chamber 2, so that the potting compound, which has a relatively high viscosity in the liquid state, does not press into one Gap between that metallic or ceramic housing 3 of the vacuum interrupter 2 and the plastic element 16 can penetrate.

After the casting compound has hardened, the movable conductor part 12, the actuating member 8, the insulation body 7 and the sealing arrangement 10 and, if appropriate, further components of the switching device are inserted into the cavity enclosed by the plastic part, and the cavity is filled with the insulation liquid. The cavity is then closed in a liquid-tight manner by fitting the cover 13.

Claims (14)

1. High-voltage switching device comprising a housing body (1), in which a vacuum interrupting chamber (2) is provided that comprises an immoveable switching contact element (4) and a switching contact element (5) that can move in the axial direction,
   the moveable switching contact element (5) extending out of the vacuum interrupting chamber (2) and being connected to an actuator (8), which can move in the axial direction, by means of an insulating body (7), and conductor parts (12, 13, 14) that form the current path being connected to the immoveable switching contact element (4) and the moveable switching contact element (5), and
   a cavity (22) that is filled with insulating liquid being made in the housing body (1), the moveable switching contact element (5) extending out of the vacuum interrupting chamber (2) and into the cavity (22), and the actuator (8) extending out of the cavity (22),
   characterised in that
   a sealing arrangement (10) that is arranged in the cavity (22) is provided, which seals the actuator (8) with respect to the housing body (1), the sealing arrangement (10) comprising a bellows (11) that is arranged in the cavity (22) and surrounds the actuator (8), one end of the bellows (11) being sealed with respect to the actuator (8) and the other end of the bellows being sealed with respect to the housing body (1).
2. High-voltage switching device according to claim 1, characterised in that the cavity (22) is closed by means of a cover (13) that is sealed with respect to the housing body (1), one end of the bellows (11) being sealed with respect to the cover (13).
3. High-voltage switching device according to any of claims 1 to 2, characterised in that the housing body (1) comprises a plastics body (16) that surrounds the cavity (22) at least in part.
4. High-voltage switching device according to claim 3, characterised in that the plastics body (16) consists of a plurality of plastics elements (16A, 16B, 16C) that are interconnected.
5. High-voltage switching device according to claim 4, characterised in that the plastics body (16) comprises a cylindrical plastics element (16C), which surrounds the sealing arrangement (10) at least in part.
6. High-voltage switching device according to either claim 4 or claim 5, characterised in that the plastics body (16) comprises a first bowl-shaped plastics element (16A) and a second bowl-shaped plastics element (16B), the conductor parts (12, 13, 14) that form the current path comprising a moveable conductor part (12), which is electrically connected to the moveable contact element (5), the moveable conductor part (5) being arranged in the cavity (22) and being surrounded by the first and second plastics element (16A, 16B) at least in part.
7. High-voltage switching device according to any of claims 1 to 6, characterised in that the housing body (1) comprises a casting body (15), which receives the vacuum interrupting chamber (2) and the plastics body (16).
8. High-voltage switching device according to claim 7, characterised in that the plastics body (16) is sealed with respect to the vacuum interrupting chamber (2).
9. High-voltage switching device according to claim 8, characterised in that cutting edges (21) are provided on the plastics body (16), the vacuum interrupting chamber (2) comprising a housing (3) that is surrounded, at least in part, by a material (3A) into which the cutting edges (21) cut.
10. Switchgear comprising a high-voltage switching device according to any of claims 1 to 9.
11. Method for producing a high-voltage switching device according to any of claims 1 to 9, the high-voltage switching device comprising:

    a plastics body (16) surrounding the cavity (22) that is filled with an insulating liquid,

    comprising the following method steps:

    providing a casting mould,

    placing the vacuum interrupting chamber (2) and the plastics body (16) in the casting mould,

    casting the space (19) between the vacuum interrupting chamber (2) and the plastics body (16) with a casting compound in order to provide a casting body (15) that surrounds the vacuum interrupting chamber and the plastics body and in which a cavity (22) that is surrounded by the plastics body (16), at least in part, is made,

    inserting the actuator (8) and the insulating body (7) and the sealing arrangement (10) into the cavity,

    filling the cavity (22) with an insulating liquid, and

    closing the cavity (22) by means of a cover (13) that is sealed with respect to the casting body (15) or the plastics body (16).
12. Method according to claim 11, characterised in that the plastics body (16) is composed of a plurality of plastics elements (16A, 16B, 16C) that are interconnected.
13. Method according to claim 12, characterised in that the plastics body (16) is composed of two bowl-shaped plastics elements (16A, 16B) and one cylindrical plastics element (16C).
14. Method according to any of claims 1 to 13, characterised in that the casting compound is an epoxy resin.

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