Electric switching device

Abstract

The invention relates to an electric switching device (1). The switching device (1) comprises: a housing (3) having a housing gas chamber (13) filled with a gas; a breaker unit (5) which is arranged in the housing (3) and has an electric contact element; a base (7) which is arranged in the housing (3), supports the breaker unit (5), is electrically connected to the contact element of the breaker unit (5), and has a base gas chamber (15); and a heat sink (12) which is arranged in the base gas chamber (15).

Description

[0001] Description

[0002] Electrical switching device

[0003] The invention relates to an electrical switching device comprising a housing with a housing gas space filled with a gas and an interrupter unit arranged in the housing.

[0004] The switching device is, for example, a circuit breaker. A circuit breaker is designed to quickly and safely interrupt high overload and short-circuit currents. The gas in the housing gas space is typically a pressurized insulating gas to increase dielectric strength, for example, purified and dehumidified air or sulfur hexafluoride. Such a switching device has electrical conductors arranged within the housing. A high-voltage circuit breaker is specifically designed to switch high currents at high voltages. Therefore, a high-voltage circuit breaker is also designed to isolate high voltages.

[0005] An electric current flowing in an electrical conductor heats the conductor and causes a so-called ohmic power loss associated with the heating. Current standards specify a maximum permissible temperature rise for the conductor of a switching device, which limits the maximum permissible electric current in the conductor. Therefore, technical or design measures must be taken to limit the maximum temperature rise of the conductor. At the same time, the aim of these measures is to maximize the current in the conductor, that is, to bring this current as close as possible to the permissible electric current.

[0006] To limit the heating of a conductor in a switching device and the ohmic power loss, a large conductor cross-section and / or a suitable conductor material with high electrical conductivity can be used, for example. These measures increase the cost of a conductor due to the quantity and / or the choice of material.

[0007] The invention is based on the objective of providing an electrical switching device with the above-mentioned properties, which is improved in particular with regard to limiting the heating of an electrical conductor of the switching device.

[0008] The problem is solved according to the invention by an electrical switching device with the features of claim 1.

[0009] Advantageous embodiments of the invention are the subject of the dependent claims.

[0010] An electrical switching device according to the invention comprises

[0011] - a housing with a housing gas chamber that is filled with a gas ,

[0012] - a breaker unit arranged in the housing with an electrical contact element ,

[0013] - a base arranged in the housing, supporting the breaker unit, which is electrically connected to the contact element of the breaker unit and has a base gas space, and

[0014] - a cooling element located in the base gas space.

[0015] The statement that the switching device has a base with the aforementioned properties does not preclude the possibility that the switching device has several bases, in particular two bases supporting the interrupter unit on opposite sides. The statement is therefore to be understood as meaning that the switching device has at least one base with the aforementioned properties. The statement that the interrupter unit has an electrical contact element is to be understood as meaning that the interrupter unit has at least one electrical contact element. It is not necessary for every electrical contact element of the interrupter unit to be electrically connected to the base, but only for at least one to be.

[0016] When an electric current flows through the base, the base heats up. This also heats the gas in the base's gas chamber. The invention aims to cool the gas in the base's gas chamber, and thereby the base itself, and to reduce the base's electrical resistance. A heat sink in the base's gas chamber serves this purpose. The heat sink is surrounded by gas flowing through the base's gas chamber, thus cooling both the gas in the base's gas chamber and the base itself. Positioning the heat sink within the base's gas chamber, rather than outside of it for cooling the gas in the switching device, has the advantage that the base shields against high electric field strengths.In contrast, arranging the heat sink for cooling the gas in the switching device outside the base would cause high electric field strengths between the heat sink and the housing, since a heat sink for cooling the gas has the largest possible surface area and is therefore designed to be finely structured and sharp-edged, for example by means of cooling fins.

[0017] In one embodiment of the switching device, the heat sink comprises a base body and a cooling structure attached to the base body. For example, the cooling structure has cooling fins projecting from the base body. The heat sink can be fixed in the socket via the base body. The cooling structure serves to cool the gas in the socket's gas chamber. Cooling fins are suitable for cooling the gas because they provide a large surface area for cooling. In another embodiment of the switching device, the heat sink is attached to a wall of the socket by clamps and / or screws and / or adhesive. This allows the heat sink to be firmly connected to the socket.

[0018] In a further embodiment of the switching device, a thermal interface material is arranged between the heat sink and the wall of the socket. This thermal interface material is, for example, thermal paste, a thermal pad, or a thermal adhesive. The thermal interface material advantageously improves heat conduction between the heat sink and the socket, and thus heat dissipation from the socket.

[0019] In a further embodiment of the switching device, the heat sink is arranged in an area of ​​the base gas chamber with a high temperature load. This makes the heat dissipation from the base particularly efficient.

[0020] In a further embodiment of the switching device, the base has at least one base opening through which the base gas space is connected to the housing gas space. In particular, the base has several base openings through which the base gas space is connected to the housing gas space. These base openings allow a gas flow between the housing gas space and the base gas space, leading to a more efficient gas flow around the heat sink and thus to more efficient heat transfer by convection from the base gas space to the housing gas space. This further increases the heat removal from the base gas space by convection. Consequently, the base can be cooled even more effectively, increasing the maximum permissible electrical current in the base or, for example, allowing a smaller conductor cross-section of the base to carry the same current without exceeding the maximum permissible temperature of the base.In a further embodiment of the switching device, the base is attached to the housing via an electrically insulating bracket, and the bracket has at least one mounting opening through which the housing gas chamber is connected to the base gas chamber. Such a mounting opening also improves the gas flow between the base gas chamber and the housing gas chamber, and thus the heat dissipation from the base gas chamber and the cooling of the base.

[0021] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. These show:

[0022] FIG 1 shows a schematic sectional view of a section of an exemplary embodiment of a switching device,

[0023] FIG 2 shows a perspective sectional view of a switching device in the area of ​​a heat sink.

[0024] Corresponding parts in the figures are marked with the same reference symbols.

[0025] Figure 1 (FIG 1) shows a schematic sectional view of a section of an exemplary embodiment of a switching device 1 according to the invention. The components of the switching device 1 shown in Figure 1 are a housing 3, an interrupter unit 5, a base 7, a bracket 9, a housing feedthrough 11, and a heat sink 12. The interrupter unit 5, the base 7, the bracket 9, and the heat sink 12 are arranged in the housing 3. The housing 3 is, for example, made of metal and is grounded, that is, connected to earth potential. The housing 3 surrounds a housing gas chamber 13, which is filled with a gas. The gas is an insulating gas under pressure, for example, purified and dehumidified air or sulfur hexafluoride.

[0026] The interrupter unit 5 has two switching elements 40 (see Figure 2, where only one switching element is shown) which are in contact with each other in a first switching position and separated from each other in a second switching position. For example, the interrupter unit 5 has a vacuum switching tube in which the switching elements are arranged. However, the type and design of the interrupter unit 5 are not relevant to the invention.

[0027] The base 7 supports the breaker unit 5 and is predominantly made of electrically conductive material, in particular metal. The base 7 is electrically connected to an electrical contact element (not shown) of the breaker unit 5. The base 7 has a base gas chamber 15, which is connected to the housing gas chamber 13 by base openings 17 of the base 7, so that gas can flow through the base openings 17 between the housing gas chamber 13 and the base gas chamber 15. The heat sink 12 is arranged in the base gas chamber 15.

[0028] Furthermore, the base 7 is attached to the housing 3 via the bracket 9. The bracket 9 is made of electrically insulating material, so that the base 7 is electrically insulated from the housing 3. The bracket 9 also has a mounting gas chamber 19, which is connected to the base gas chamber 15 and, via at least one mounting opening 21, to the housing gas chamber 13, so that gas can flow through the mounting opening 21 and the mounting gas chamber 19 between the housing gas chamber 13 and the base gas chamber 15. The housing feedthrough 11 comprises an insulator 23, an electrical conductor 25, and a cover 27. The insulator 23 is made of electrically insulating material and surrounds a feedthrough gas chamber 29. The insulator 23 and the conductor 25 are each straight. The conductor 25 is designed as a waveguide.

[0029] The insulator 23 projects obliquely upwards from the housing 3. The through-gas chamber 29 is connected to the housing gas chamber 13, allowing gas to flow between the housing gas chamber 13 and the through-gas chamber 29.

[0030] The cover 27 closes the insulator 23 at its end facing away from the housing 3 and is made of electrically conductive material, in particular metal. An electrically conductive connecting lug 33 for electrically contacting the switching device 1 is arranged on the side of the cover 27 facing away from the passage gas space 29.

[0031] The conductor 25 electrically connects the base 7 and the cover 27 and is guided through the feedthrough gas space 29 at a distance from the insulator 23. The conductor 25 has an open first conductor end 35, via which the conductor 25 is electrically connected to the base 7. The conductor 25 also has a second conductor end 39, which is electrically connected to and closed by the cover 27.

[0032] Figure 2 (FIG 2) shows a perspective sectional view of the switching device 1 in the area of ​​the heat sink 12. The heat sink 12 has a base body 41 and a cooling structure 43 arranged on the base body 41. The cooling structure 43 has cooling fins 45 projecting from the base body 41. The heat sink 12 is attached to a wall 47 of the base 7 by clamps and / or screws (not shown) and / or by adhesive bonding. A thermal interface material 49 is arranged between the heat sink 12 and the wall 47 of the base 7. The thermal interface material 49 is, for example, a thermal paste, a thermal pad, or a thermal adhesive.

[0033] The heat sink 12 is arranged in a region 51 of the base gas chamber 15 with a high temperature load. In the embodiment shown here, this region 51 is located near the interrupter unit 5.

[0034] The base 7 and the conductor 25 form an electrical current path between the interrupter unit 5 and the terminal lug 33. When an electric current flows in this current path, the base 7 heats up. This heats the gas in the base gas chamber 15. The heat sink 12 is surrounded by this gas and cools the gas, and thus the base 7, through its cooling structure 43. A gas flow can establish itself between the housing gas chamber 13 and the base gas chamber 15 through the base openings 17 and the mounting opening 21, leading to heat transfer by convection from the base gas chamber 15 to the housing gas chamber 13. The gas-surrounded heat sink 12 thus improves the heat dissipation from the base gas chamber 15 by convection. The gas flow is illustrated by arrows in Figure 1.Thus, the socket 7 can be effectively cooled, increasing the maximum permissible electric current in the socket 7, or, for example, allowing a smaller conductor cross-section of the socket 7 to carry the same current without exceeding the maximum permissible temperature of the socket 7.

[0035] Although the invention has been further illustrated and described in detail by preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by the person skilled in the art without leaving the scope of protection of the invention.

Claims

Patent claims 1. Electrical switching device (1) , comprising - a housing (3) with a housing gas space (13) which is filled with a gas, - a breaker unit (5) arranged in the housing (3) with an electrical contact element, - a base (7) arranged in the housing (3) supporting the interrupter unit (5), which is electrically connected to the contact element of the interrupter unit (5) and has a base gas space (15), and - a cooling element (12) arranged in the base gas space (15) .

2. Switching device (1) according to claim 1, wherein the heat sink (12) has a base body (41) and a cooling structure (43) arranged on the base body (41).

3. Switching device (1) according to claim 2, wherein the cooling structure (43) has cooling fins (45) projecting from the base body (41).

4. Switching device (1) according to one of the preceding claims, wherein the heat sink (12) is attached to a wall (47) of the base (7) by clamps and / or screws and / or adhesive.

5. Switching device (1) according to claim 4, wherein a heat conducting medium (49) is arranged between the heat sink (12) and the wall (47) of the base (7).

6. Switching device (1) according to claim 5, wherein the thermal conducting medium (49) is a thermal paste, a thermal pad or a thermal adhesive.

7. Switching device (1) according to one of the preceding Claims, wherein the heat sink (12) is located in an area of ​​the Base gas space (15) is arranged with a high temperature load.

8. Switching device (1) according to one of the preceding claims, wherein the base (7) has at least one base opening (17) through which the base gas space (15) is connected to the housing gas space (13).

9. Switching device (1) according to one of the preceding claims, wherein the base (7) has several base openings (17) through which the base gas space (15) is connected to the housing gas space (13).

10. Switching device (1) according to one of the preceding claims, wherein the base (7) is attached to the housing (3) via an electrically insulating holder (9) and the holder (9) has at least one holder opening (21) through which the housing gas space (13) is connected to the base gas space (15).

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