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) 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 base (7) which is provided in the housing (3) and supports the interrupter unit (5). The base (7) is electrically connected to the contact element of the interrupter unit (5) and has a base gas chamber (15), and the base (7) has a plurality of base openings (17, 19) by means of which the base gas chamber (15) is connected to the housing gas chamber (13).

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 and

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

[0014] - the base has several base openings through which the base gas space is connected to the casing 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, in particular two, such bases. 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. According to the invention, the base has several base openings through which the base gas chamber is connected to the housing gas chamber. The invention aims to dissipate heat from the base by allowing heated gas from the base gas chamber to escape through at least one base opening, while simultaneously allowing cooler gas from the housing gas chamber to flow into the base gas chamber through at least one base opening to cool the base and reduce its electrical resistance. This creates a gas flow into and out of the base, which promotes heat transfer by convection.The base openings thus effectively cool the base, increasing the maximum permissible electrical current within it or allowing, for example, a smaller conductor cross-section to carry the same current without exceeding the maximum permissible base temperature. Furthermore, the gas flow and flow velocity within the base can be influenced by a suitable design of the base openings. A higher flow velocity promotes heat transfer by convection and thus increases the current-carrying capacity of the base. Additionally, base openings are sometimes strategically placed in areas with particularly high base temperatures, thereby reducing the temperature in these areas.

[0017] In one design of the switching device, the base openings are arranged in areas of the base with low electric field strengths. The base openings are thus arranged according to the field strength distribution within the switching device. This ensures that the base openings do not cause critical electric field strengths within the switching device. This is particularly advantageous when the switching device is a high-voltage circuit breaker, in order to manage high electric field strengths within the switching device.

[0018] In a further embodiment of the switching device, the first socket openings are arranged in a ring around an end region of the interrupter unit. This region is suitable for the arrangement of socket openings because the end region of the interrupter unit is usually electrically shielded, resulting in low field strengths in this area.

[0019] In a further embodiment of the switching device, the first base openings are formed by a ring structure of the base that runs around the end region of the interrupter unit, has sections adjacent to the end region of the interrupter unit, and forms the first base openings between these sections by being spaced apart from the end region of the interrupter unit. For example, the ring structure is made of a plastic. Furthermore, the first base openings are, for example, evenly distributed along the ring structure. In particular, the base can, for example, have three first base openings. Thus, in these embodiments of the switching device, the first base openings are formed by a ring structure that is adjacent to the end region of the interrupter unit in sections and is spaced apart from the end region of the interrupter unit between these sections.The ring structure therefore allows the end section of the breaker unit to be held against the base. A uniform distribution of the first base openings along the ring structure, for example with three first base openings, enables uniform support of the end section of the breaker unit by the adjacent sections of the ring structure.

[0020] In a further embodiment of the switching device, at least a second base opening is arranged in an end region of the base facing an end region of the interrupter unit. In a further embodiment of the switching device, at least a second base opening is arranged in a region of the base that widens in a funnel shape towards an end region of the interrupter unit. This arrangement of two base openings is suitable because, due to the widening of the base towards the end region of the interrupter unit, the second base openings are located in areas of low electric field strength.

[0021] In a further embodiment of the switching device, at least a second base opening is arranged in a region of the base where the base is connected to an electrical conductor of a housing bushing. This arrangement of a second base opening is suitable because the second base opening is located in the "field shadow" of the connection between the base and the electrical conductor, and thus in a region of low electric field strength.

[0022] In a further embodiment of the switching device, all edges of each second socket opening are rounded. This prevents high electric field strengths caused by sharp edges of the second socket openings.

[0023] In a further embodiment of the switching device, several second base openings are arranged distributed along the circumference of the base. For example, the base has three second base openings. This can particularly promote gas flow between the housing gas space and the base gas space, for example by arranging one second base opening on the top side of the base and at least one second base opening on the side of the base.

[0024] 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:

[0025] FIG 1 shows a schematic sectional view of a section of an exemplary embodiment of a

[0026] Switching device,

[0027] FIG 2 shows a first perspective sectional view of end areas of a base and an interruption unit of a switching device,

[0028] FIG 3 shows a second perspective sectional view of the end areas of the base and the interruption unit shown in Figure 2.

[0029] FIG 4 shows a view of the end regions of the base and the interrupt unit shown in Figures 2 and 3 from inside the interrupt unit.

[0030] FIG 5 shows a perspective view of a first embodiment of a base for a switching device,

[0031] FIG 6 shows a perspective view of a second embodiment of a base for a switching device,

[0032] FIG 7 shows a perspective view of a third embodiment of a base for a switching device.

[0033] 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.

[0034] 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.

[0035] The interrupter unit 5 has two switching elements 40 (see Figures 2 to 4, where only a section of 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.

[0036] 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 a first base opening 17 and a second base opening 19 of the base 7, so that gas can flow through the base openings 17 and 19 between the housing gas chamber 13 and the base gas chamber 15. 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.

[0037] 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 space 29. The insulator 23 and the conductor 25 are each straight. The conductor 25 is designed as a waveguide.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The base 7 and the conductor 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 heats up. This heats the gas in the base gas chamber 15. At least some of this gas flows through the second base opening 19 from the base gas chamber 15 into the housing gas chamber 13. Simultaneously, cooler gas flows through the first base opening 17 from the housing gas chamber 13 into the base gas chamber 15. This gas cools the base 7, thereby reducing its electrical resistance and increasing its current-carrying capacity.

[0042] Base 7. The flow of the gas is represented by arrows in Figure 1.

[0043] Figures 2 to 4 show an embodiment of a switching device 1 according to the invention with first base openings 17, which are arranged in the area in which the interrupting unit 5 of the switching device 1 is supported by the base 7. Only one end region 41 of the base 7 and one end region 43 of the interrupting unit 5 are shown in each figure. Figure 2 (FIG 2) and Figure 3 (FIG 3) each show a perspective sectional view of the end regions 41, 43 of the base 7 and the interrupting unit 5, respectively. Figure 4 (FIG 4) shows a view of the end regions 41, 43 of the base 7 and the interrupting unit 5 from the interior of the interrupting unit 5.

[0044] The end region 41 of the base 7 comprises a metallic structure that surrounds the end region 43 of the interrupting unit 5 in a bell-like fashion. The end of this metallic structure is curved and rounded towards the end region 43 of the interrupting unit 5 in order to reduce the electric field strength in this region. A ring structure 47, made of a plastic material, is inserted into a groove 45 running along the inside of the metallic structure of the end region 41 of the base 7 and extends around the end region 43 of the interrupting unit 5. The ring structure 47 holds the end region 43 of the interrupting unit 5 in the end region 41 of the base 7. For this purpose, the ring structure 47 has sub-regions 49 that abut the end region 43 of the interrupting unit 5.Simultaneously, the ring structure 47 forms the first socket openings 17 of the socket 7 by being spaced between the sub-regions 49 and the end region 43 of the interrupter unit 5. This position of the first socket openings 17 is advantageous because the first socket openings 17 are located in the region of low electric field strengths, since the metallic structure of the end region 41 of the socket 7 shields electric fields in the region of the first socket openings 17.

[0045] Figures 5 to 7 show perspective views of various embodiments of a base 7, each with at least one second base opening 19.

[0046] Figure 5 (FIG 5) shows an embodiment of a base 7 with two second base openings 19, each arranged in a region of the base 7 where the base 7 is connected to the electrical conductor 25 of a housing feedthrough 11. A conductor opening 51 in the base 7 for the conductor 25 is shown. The second base openings 19 are arranged below the conductor opening 51 for the conductor 25, with only one of the second base openings 19 being visible in Figure 5 (the other is arranged on the opposite side of the base 7).

[0047] Figure 6 (FIG 6) shows an embodiment of a base 7 with a second base opening 19, which is arranged in an end region 41 of the base 7 facing an end region 43 (not shown) of the interrupter unit 5. The second base opening 19 is arranged on the upper side in a region of the base 7 that widens in a funnel shape towards an end region 43 (not shown) of the interrupter unit 5.

[0048] Figure 7 (FIG 7) shows an embodiment of a base 7 with three second base openings 19, which are located in a

[0049] The end region 41 of the base 7 is arranged facing an end region 43 (not shown) of the interrupter unit 5. A second base opening 19 is arranged analogously to Figure 6 on the upper side in a region of the base 7 that widens in a funnel shape towards the end region 43 of the interrupter unit 5. The other two second base openings 19 are arranged laterally in the same region of the base 7, with only one of these lateral base openings 19 being visible in Figure 7.

[0050] In all embodiments shown in Figures 5 to 7, the positions of the second base openings 19 are chosen such that low electric field strengths prevail at these positions. For example, in the embodiment shown in Figure 5, the second base openings 19 are located in the "field shadow" of the conductor opening 51. In the embodiments shown in Figures 6 and 7, electric fields in the area of ​​the second base openings 19 are reduced by the cross-section of the base 7, which widens towards the end region 41. Furthermore, in all embodiments shown in Figures 5 to 7, all edges of each second base opening 19 are rounded to avoid high electric field strengths caused by sharp edges of the second base openings 19.

[0051] 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 and - 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), wherein - the base (7) has several base openings (17, 19) through which the base gas space (15) is connected to the housing gas space (13).

2. Switching device (1) according to claim 1, wherein the base openings (17, 19) are arranged in areas of the base (7) with low electric field strengths.

3. Switching device (1) according to claim 1 or 2, wherein first base openings (17) are arranged in a ring-like arrangement around an end region (43) of the interrupter unit (5).

4. Switching device (1) according to claim 3, wherein the first base openings (17) are formed by a ring structure (47) of the base (7) formed, which runs around the end area (43) of the interrupter unit (5), at which End area (43) of the interrupter unit (5) adjacent has sub-areas (49) and between these The first base openings (17) are formed in the sub-areas (49) by separating the sub-areas (49) from the The end area (43) of the interrupter unit (5) is spaced apart.

5. Switching device (1) according to claim 4, wherein the ring structure (47) is made of a plastic.

6. Switching device (1) according to claim 4 or 5, wherein the first base openings (17) are evenly distributed along the ring structure (47).

7. Switching device (1) according to one of claims 3 to 6, wherein the base (7) has three first base openings (17).

8. Switching device (1) according to one of the preceding claims, wherein at least a second base opening (19) is arranged in an end region (41) of the base (7) which faces an end region (43) of the interrupter unit (5).

9. Switching device (1) according to one of the preceding claims, wherein at least a second base opening (19) is arranged in a region of the base (7) which widens in a funnel shape to an end region (43) of the interrupter unit (5).

10. Switching device (1) according to one of the preceding claims, wherein at least a second base opening (19) is arranged in a region of the base (7) in which the base (7) is connected to an electrical conductor (25) of a housing feedthrough (11).

11. Switching device (1) according to one of claims 8 to 10, wherein all edges of each second base opening (19) are rounded.

12. Switching device (1) according to one of claims 8 to 11, wherein several second base openings (19) are arranged distributed along a circumference of the base (7).

13. Switching device (1) according to one of claims 8 to 12, wherein the base (7) has three second base openings (19).

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