Electric switching device

Abstract

The invention relates to an electric switching device (1). A switching device (1) comprises a housing (3) having a housing gas chamber (13) which is filled with a gas, an interrupter unit (5) which is provided in the housing (3) and has an electrical contact element, and a housing feed-through (11) having a hollow electrical conductor (25) which is guided through a feed-through gas chamber (29) of the housing feed-through (11), said feed-through gas chamber being connected to the housing gas chamber (13). The hollow conductor (25) is electrically connected to the contact element of the interrupter unit (5) and has an open first hollow conductor end (35) connected to the housing gas chamber (13), a closed second hollow conductor end (39), and at least one hollow conductor opening (41) between the hollow conductor ends (35, 39).

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.

[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, thereby limiting 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. 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.

[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 and

[0013] - a housing feedthrough comprising an electrical waveguide which is guided through a feedthrough gas space of the housing feedthrough connected to the housing gas space, wherein

[0014] - the waveguide is electrically connected to the contact element of the interrupter unit and has an open first waveguide end connected to the housing gas space, a closed second waveguide end and at least one waveguide opening arranged between the waveguide ends.

[0015] A housing feedthrough of an electrical switching device is generally understood to be an assembly that enables an electrical connection between an electrical conductor located inside the housing and an electrical conductor located outside the housing. In the switching device according to the invention, the housing feedthrough through the waveguide enables the electrical connection of a contact element of the interrupter unit with an electrical conductor located outside the housing.

[0016] The statement that the switching device has a housing penetration with the aforementioned properties does not preclude the possibility that the switching device has several such housing penetrations. The statement should therefore be understood to mean that the switching device has at least one housing penetration with the aforementioned properties.

[0017] The wording that the waveguide has an open first waveguide end connected to the housing gas space is to be understood as meaning that gas can flow into the interior of the waveguide between the housing gas space and this waveguide end.

[0018] 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 that every electrical contact element of the interrupter unit be electrically connected to the waveguide, but only that at least one be. Furthermore, the statement that the waveguide is electrically connected to the contact element of the interrupter unit is not to be understood as meaning that the waveguide is necessarily directly connected to the contact element of the interrupter unit. Rather, the waveguide can also be electrically connected to the contact element of the interrupter unit via one or more electrical conductors (in particular via a base supporting the interrupter unit, see below), so that an electric current can flow between the waveguide and the contact element of the interrupter unit.When an electric current flows through the waveguide, the waveguide heats up. This also heats the gas inside the waveguide. According to the invention, the waveguide has at least one opening located between the open first end of the waveguide and the closed second end. The invention aims to dissipate heat from the waveguide by allowing heated gas to escape through at least one opening, thereby cooling the waveguide and reducing its electrical resistance.

[0019] In one embodiment of the switching device, each waveguide opening is arranged above the first end of the waveguide. This allows heated gas from the interior of the waveguide to flow through each opening into the housing gas space surrounding the waveguide. Simultaneously, gas from the housing gas space flows into the interior of the waveguide. Thus, heat is removed from the interior of the waveguide by convection, as heated gas from the interior is replaced by cooler gas from the housing gas space. The at least one waveguide opening therefore creates a chimney effect within the waveguide, dissipating heat. Compared to a waveguide without an opening, this cools the waveguide, reducing its electrical resistance and increasing its current-carrying capacity.

[0020] In a further embodiment of the switching device, each waveguide opening is arranged in the region of the second waveguide end. This allows heat to be advantageously dissipated from the waveguide between both waveguide ends and thus almost along its entire length by gas escaping from its interior.

[0021] In a further embodiment of the switching device, the waveguide is straight with a longitudinal axis connecting the waveguide ends. This simplifies the manufacture of the waveguide, for example compared to a curved waveguide.

[0022] In a further embodiment of the switching device, each waveguide opening is designed as an elongated opening that runs parallel to the longitudinal axis of the waveguide. For example, each waveguide opening is designed as a slot whose longitudinal sides run parallel to the longitudinal axis of the waveguide. This embodiment of the switching device takes into account that the electric current in the waveguide flows along its longitudinal axis. Designing a waveguide opening as an opening running parallel to this longitudinal axis advantageously reduces the electrical resistance of the waveguide compared to a differently designed waveguide opening.

[0023] In a further embodiment of the invention, the switching device has a base arranged in the housing that supports the interrupter unit. The first end of the waveguide is connected to this base, and the waveguide is electrically connected to the contact element of the interrupter unit via this base. Thus, the base supports the interrupter unit within the housing. Furthermore, the base electrically connects the waveguide to the contact element of the interrupter unit. For this purpose, the base is at least partially made of an electrically conductive material.

[0024] In a further embodiment of the switching device, the base has a base gas chamber to which the first waveguide end is open. The base has, for example, at least one base opening through which the base gas chamber is connected to the housing gas chamber. Because the first waveguide end is open to the base gas chamber, gas can flow from the base gas chamber into the interior of the waveguide. Furthermore, by connecting the base gas chamber to the housing gas chamber, gas can flow from the housing gas chamber through the base gas chamber into the interior of the waveguide.

[0025] In a further embodiment of the switching device, the base is attached to the housing by an electrically insulating bracket, and the bracket has at least one opening through which the gas space of the housing is connected to the gas space of the base. This embodiment of the switching device allows gas from the gas space of the housing to flow through an opening in the bracket of the base and the gas space of the base into the interior of the waveguide.

[0026] In a further embodiment of the switching device, the housing feedthrough features an insulator made of an electrically insulating material, which surrounds the feedthrough gas space. The insulator is spaced apart from the waveguide, thus allowing the gas to flow in the feedthrough gas space between the insulator and the waveguide.

[0027] 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:

[0028] FIG 1 shows a schematic sectional view of a section of an exemplary embodiment of a switching device,

[0029] FIG 2 shows a perspective sectional view of the switching device shown in Figure 1 in the area of ​​one end of a housing feedthrough of the switching device.

[0030] Corresponding parts are provided with the same reference numerals in the figures. Figure 1 (FIG 1) shows a schematic sectional view of a section of an 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 holder 9, and a housing feedthrough 11. The interrupter unit 5, the base 7, and the holder 9 are arranged in the housing 3.

[0031] The housing 3, for example, is made of metal and is grounded, meaning it is connected to earth potential. The housing 3 surrounds a housing gas chamber 13, which is filled with a gas. The gas is a pressurized insulating gas, for example, purified and dehumidified air or sulfur hexafluoride.

[0032] The interrupter unit 5 has two (not shown) switching elements 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.

[0033] The base 7 supports the interrupter unit 5 and is made at least predominantly of electrically conductive material, in particular metal. The base 7 is electrically connected to an electrical contact element (not shown) of the interrupter 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.

[0034] 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, through 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.

[0035] The housing feedthrough 11 comprises an insulator 23, an electrical waveguide 25, and a cover 27. The insulator 23 is made of electrically insulating material and surrounds a feedthrough gas space 29. The insulator 23 and the waveguide 25 are each straight and have a common longitudinal axis 30.

[0036] Figure 2 ( FIG 2 ) shows a perspective sectional view of the housing feedthrough 11 in the area of ​​the cover 27 .

[0037] The insulator 23 is tubular in shape, with its outer surface featuring insulator shields 31, each extending in a ring-like fashion around the longitudinal axis 30 to lengthen creepage paths for leakage currents flowing on the outer surface. The insulator 23 projects obliquely upwards from the housing 3. The feedthrough gas space 29 is connected to the housing gas space 13, allowing gas to flow between the housing gas space 13 and the feedthrough gas space 29.

[0038] 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 feedthrough gas space 29. The waveguide 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 waveguide 25 has an open first waveguide end 35, which is connected to the base 7 and through which the waveguide interior 37 of the waveguide 25 is connected to the base gas space 15. The waveguide 25 is also electrically connected to the base 7 via the first waveguide end 35. Furthermore, the waveguide 25 has a second waveguide end 39 which is electrically connected to and sealed by the cover 27.

[0039] Furthermore, the waveguide 25 has two waveguide openings 41, which are arranged in the region of the second waveguide end 39. Each waveguide opening 41 is designed as an elongated hole, the longitudinal sides 43 of which run parallel to the longitudinal axis 30.

[0040] The base 7 and the waveguide 25 therefore 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 and the waveguide 25 heat up. This heats the gas in the base gas space 15 and the waveguide interior 37. At least some of this gas flows through the waveguide interior 37 to the waveguide openings 41 and through the waveguide openings 41 into the feedthrough gas space 29 surrounding the waveguide openings 41. Simultaneously, cooler gas flows through each base opening 17 and mounting opening 21 from the housing gas space 13 into the base gas space 15 and from there into the waveguide interior 37. This gas cools the socket 7 and the waveguide 25, thereby reducing the electrical resistances of the socket 7 and the waveguide 25 and increasing the current-carrying capacity of the socket 7 and the waveguide 25.The gas flow in the switching device 1 is shown by arrows in Figure 1. 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 those skilled in the art without departing from 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 and - a housing feedthrough (11) comprising an electrical waveguide (25) which is guided through a feedthrough gas space (29) of the housing feedthrough (11) connected to the housing gas space (13), wherein - the waveguide (25) is electrically connected to the contact element of the interrupter unit (5) and has an open first waveguide end (35) connected to the housing gas space (13), a closed second waveguide end (39) and at least one waveguide opening (41) arranged between the waveguide ends (35, 39).

2. Switching device (1) according to claim 1, wherein each waveguide opening (41) is arranged above the first waveguide end (35).

3. Switching device (1) according to claim 1 or 2, wherein each waveguide opening (41) is arranged in the region of the second waveguide end (39).

4. Switching device (1) according to one of the preceding claims, wherein the waveguide (25) is formed with a longitudinal axis (30) connecting the waveguide ends (35, 39).

5. Switching device (1) according to claim 4, wherein each waveguide opening (41) is designed as an elongated opening which runs parallel to the longitudinal axis (30) of the waveguide (25).

6. Switching device (1) according to claim 4 or 5, wherein each waveguide opening (41) is designed as an elongated hole, the longitudinal sides (43) of which run parallel to the longitudinal axis (30) of the waveguide (25).

7. Switching device (1) according to one of the preceding claims with a base (7) arranged in the housing (3) supporting the interrupter unit (5), with which the first waveguide end (35) is connected and via which the waveguide (25) is electrically connected to the contact element of the interrupter unit (5).

8. Switching device (1) according to claim 7, wherein the base (7) has a base gas space (15) to which the first waveguide end (35) is open.

9. Switching device (1) according to claim 8, 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).

10. Switching device (1) according to one of claims 7 to 9, wherein the base (7) is attached to the housing (3) by 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).

11. Switching device (1) according to one of the preceding claims, wherein the housing feedthrough (11) has an insulator (23) made of an electrically insulating material and surrounding the feedthrough gas space (29).

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