Abstract
An electrical switching device includes a switching path and a flow device with a control valve. By way of the flow device, a fluid can flow on the switching path. The control valve additionally has a valve body. The valve body is pressed into a sealing position by the flow pressure of the flowing fluid.
Claims
1-9. (canceled)
10. An electrical switching device, comprising: a switching path; a flow device with a control valve for applying a flow of a flowing fluid to said switching path; said control valve having a movable valve body configured to be pressed into a sealing position by way of a flow pressure of the flowing fluid.
11. The electrical switching device according to claim 10, wherein said valve body is movably disposed in a clearance fit between a first stop and a second stop.
12. The electrical switching device according to claim 11, wherein said valve body is formed with a through opening to be blocked by way of one of said first and second stops.
13. The electrical switching device according to claim 10, wherein said valve body is elastically deformable.
14. The electrical switching device according to claim 10, wherein said valve body is spatially fixed.
15. The electrical switching device according to claim 14, wherein said valve body is spatially fixed at least at one point.
16. The electrical switching device according to claim 11, wherein one of said first and second stops is configured to spatially fix said valve body.
17. The electrical switching device according to claim 11, wherein one of said first and second stops is formed with a convex stop face for said valve body.
18. The electrical switching device according to claim 10, wherein said control valve is positioned in a stationary position relative to said switching path.
19. The electrical switching device according to claim 10, wherein the electrical switching device is a grounding switch.
20. The electrical switching device according to claim 19, configured as a fast-acting grounding switch.
Description
[0027] In the following text, one exemplary embodiment of the invention will be shown diagrammatically in a drawing and will be described in greater detail subsequently.
[0028] Here, in the drawing:
[0029] FIG. 1 shows a side view of an electrical switching device in the switched-off state,
[0030] FIG. 2 shows a top view of the electrical switching device known from FIG. 1 in the switched-off state,
[0031] FIG. 3 shows a top view of the electrical switching device as known from FIGS. 1 and 2 in the switched-on state,
[0032] FIG. 4 shows a perspective view of the electrical switching device known from FIGS. 1 to 3 in the switched-off state, and
[0033] FIG. 5 shows a piston plate with a control valve in a first design variant in a perspective view.
[0034] FIGS. 6, 7 and 8 show sections through the piston plate known from FIGS. 1 to 5 with a control valve in a first design variant,
[0035] FIGS. 9, 10 and 11 show a modification of the control valve in the first design variant shown in section in FIGS. 6, 7 and 8.
[0036] FIG. 12 shows a piston plate with a control valve in a second design variant in a perspective view,
[0037] FIGS. 13, 14 and 15 in each case show a section through the piston plate together with the control valve in a second design variant,
[0038] FIG. 16 shows a piston plate with a control valve in a third design variant in a perspective view, and
[0039] FIGS. 17 to 19 in each case show a section through the control valve in the third design variant known from FIG. 16.
[0040] On the basis of FIGS. 1 to 4, the construction of an electrical switching device and the method of operation of a control device will first of all be described. FIGS. 5 to 19 in each case show details of control valves in three design variants.
[0041] FIG. 1 shows a side view of an electrical switching device in section. The electrical switching device comprises an encapsulation housing 1. The encapsulation housing 1 surrounds active parts (live parts) of the electrical switching device, with the result that there is mechanical protection. Furthermore, the encapsulation housing 1 can hermetically enclose active parts of the electrical switching device, with the result that the interior of the encapsulation housing can be filled with an electrically insulating fluid. The encapsulation housing 1 prevents evaporation of the electrically insulating fluid.
[0042] The electrical switching device comprises a switching path 2. The switching path 2 extends between a first movable switching contact piece 3 and a second stationary switching contact piece 4. The second switching contact piece 4 is supported on the encapsulation housing 1 in an electrically insulated manner. The encapsulation housing 1 comprises walls made from an electrically conducting material which conduct ground potential. The second switching contact piece 4 likewise has ground potential, a grounding cable of the second switching contact piece 4 being routed to the outside through the encapsulation housing 1 in an electrically insulated manner. As a result, there is the possibility for the second switching contact piece 4 to be disconnected from the ground potential as required. This is advantageous, for example, for inspecting and testing purposes. The first switching contact piece 3 is mounted on a cylinder 5. The cylinder 5 is part of a flow device and delimits a compression volume 6. Here, the first switching contact piece 3 is of hollow-cylindrical configuration and comprises a blowing channel 7 in its interior. The blowing channel 7 opens at the free end of the first switching contact piece 3 in the switching path 2. The other end of the blowing channel 7 opens in the interior of the compression volume 6, with the result that the compression volume 6 can communicate via the blowing channel 7 with the surrounding area, in particular in the region of the switching path 2. The cylinder 5 is mounted movably and is formed from electrically insulating material. Via a connection lug 8 which is arranged between the first switching contact piece 3 and an end side of the cylinder 5, a connector line is guided to the outside in an electrically insulating manner through the wall of the encapsulation housing 1, and can be connected there to a phase conductor track to be grounded. In order to bring about displaceable guidance of the cylinder 5, a piston plate 9 is positioned so as to be seated in a stationary manner on a stem 10. Here, the stem 10 is in turn supported in a stationary manner on the encapsulation housing 1. The piston plate 9 forms a fixed wall on the compression volume 6, with the result that a change in the compression volume 6 is brought about in the case of a relative movement of the piston plate 9 with respect to the cylinder 5. In the case of a switch-on operation, that is to say in the case of an approach of the first switching contact piece 3 to the second switching contact piece 4, an increase in the compression volume 6 takes place. Conversely, in the case of a removal of the switching contact piece 3 from the second switching contact piece 4 (switch-off operation), a reduction in the compression volume 6 takes place. In the case of a switch-off operation, a compression of electrically insulating fluid is thus brought about within the compression volume. Via the blowing channel 7, said electrically insulating fluid is ejected into the switching path 2, and applies flow to, cools and reinforces the switching path 2 there and flows around a possibly burning arc. A relief opening which opens in the compression volume 6 can be switched by way of a control valve 13. The relief opening is advantageously arranged in the stationary piston plate 9. At least one control valve 13 (position, cf. FIG. 2) is arranged in the piston plate 9.
[0043] In order to bring about a displacement of the first switching contact piece 3 together with the cylinder 5, a rotatably mounted lever arm 11 is provided. The lever arm 11 is guided with its free end in a groove on the cylinder 5, with the result that a pivoting movement can be converted into a linear movement of the cylinder 5 via a pin, engaging into the groove, of the lever arm 11 (cf. FIGS. 2, 3, 4). In order to assist braking of the cylinder 5 in the switch-on and switch-off positions, stop buffers 12 are arranged on the stem 10 which supports the piston plate 9. It can be seen in the top view of FIG. 2 that the switching unit according to FIG. 1 is a multipole switching unit. That is to say, a plurality of first switching contact pieces 3 and a plurality of second switching contact pieces 4 are arranged parallel to one another and are actuated together. Therefore, a switching device, as shown in FIGS. 1 and 2, can be used for switching a multiphase electrical energy transmission system. The piston plate 9 is a substantially rectangular piston plate 9, in which two control valves 13 of identical construction are arranged. The control valves 13 serve to control the filling and emptying of the compression volume 6 with a fluid which is provided for applying a flow to the switching path 2.
[0044] Starting from the switched-off state as shown in FIGS. 1 and 2, a switch-on operation is then first of all to be described. In order to move the first switching contact pieces 3 closer to the second switching contact pieces 4, a rotation of the lever arm 11 is triggered. As a result, the cylinder 5 is moved in the direction of the second switching contact pieces 4. The compression volume 6 increases in the process. Here, the control valves 13 are oriented in such a way that a valve body 14a, 14b, 14c then opens, with the result that an inflow of fluid into the compression volume 6 preferably takes place via the control valves 13. In addition, fluid can also flow in via the blowing channels 7 of the first switching contact pieces 3. In the switched-on state (FIG. 3), the first and the second switching contact pieces 3, 4 are connected to one another in an electrically conducting manner. The compression volume 6 is filled with the greatest possible quantity of electrically insulating fluid. In the case of a switch-off operation (FIG. 3 after FIG. 2), that is to say the first switching contact pieces 3 are disconnected from the second switching contact pieces 4 and moved away from them, a reduction of the compression volume 6 takes place. In order to carry out a switch-off operation, the lever 11 is moved with a changed rotational direction. The stop buffers 12 in each case form stops for the moving cylinder 5, in order to brake the latter in its end positions. The valve bodies 14a, 14b, 14c block the control valves 13, with the result that fluid which is situated within the compression volume 6 has to flow out via the blowing channels 7 of the first switching contact pieces 3 in the direction of the second switching contact pieces 4. As a result, the switching path 2 is flooded with uncontaminated, preferably cool, electrically insulating fluid, with the result that contaminated fluid is pushed out of said region and a possibly present arc is flowed around by the electrically insulating fluid. FIG. 4 shows the position of the control valves 13 in a symbolic manner in the switched-off state. FIGS. 5, 12 and 16 show design variants of possible control valves 13. Here, the associated FIGS. 6 to 11, 13 to 15 and 17 to 19 show the method of operation of the control valves 13 or their valve bodies 14a, 14b, 14c.
[0045] Regardless of the structural configuration of the control valves 13, 13a, 13b, 13c with regard to shape, number, etc., their function is selected in each case to be identical, however, for the switching device shown in the figures (grounding switch/fast-acting grounding switch). In the case of a switch-on operation, the control valves 13, 13a, 13b, 13c are switched in such a way that a valve body 14a, 14b, 14c is moved out of its sealing position, with the result that a fluid flow can flow over out of the surrounding area into the interior of the compression volume 6. In the case of a switch-off operation, the valve body 14a, 14b, 14c is pressed into its sealing position, with the result that an outflow of fluid from the compression volume 6 which decreases in size in the case of a switch-off operation takes place via the blowing channels 7 of the first switching contact pieces 3.
[0046] FIG. 5 shows a piston plate 9 with a stem 10 as known from FIGS. 1 to 4. A first design variant of a control valve 13a is arranged twice in the piston plate 9, in each case an identical overall design having been selected. The throughflow capability is increased by way of the doubling of the control valves 13a. The control valve 13a in a first design variant has a substantially cylindrical valve body 14a with a circular cross section. The valve body 14a of the control valve 13a in a first design variant can be moved freely between a first stop 15 and a second stop 16 (cf. FIGS. 6 to 11) in the direction of a displacement axis of the cylinder 5. The valve body 14a is mounted displaceably in the manner of a clearance fit between the first and the second stop 15, 16. A plurality of curved slots are arranged distributed on the circumference in the edge region of the valve body 14a of the control valve 13a in the first design variant, which slots in each case form a through opening 17. Here, the cross section of the first stop 15 is selected in such a way that it completely covers the through openings 17 and, in the case of contact of the valve body 14a of the control valve 13a in the first design variant, said through openings 17 are blocked or dammed by the first stop 15 (cf. FIG. 6). In contrast to this, the second stop 16a is dimensioned in such a way that, on the side which faces away from the observer in FIG. 5, it performs support or contact of the valve body 14a of the control valve 13a of the first design variant in the edge region, with the result that, in the case of the valve body 14a bearing against the second stop 16, the through openings 17 are not then dammed (cf. FIG. 8). FIG. 6 shows the position of the valve body 14a during a switch-off operation, that is to say the valve body 14a is pressed into its sealing position on the first stop 15. A pressing force is brought about by way of the flow pressure of the flowing fluid which is compressed in the interior of the compression volume 6. As the pressure in the interior of the compression volume 6 increases, the pressing force on the seat of the valve body 14a in its sealing position also increases. In the case of a switch-off operation, a directional reversal of the flow pressure takes place (FIG. 7). That is to say, the compression volume 6 is increased, as a result of which the flow pressure of the flowing fluid moves the valve body 14a away from the first stop 15 and presses it in the direction of the second stop 16 (FIG. 8). The recesses 17 are then exposed, and fluid can flow over via the recesses 17 of the valve body 14a into the interior of the compression volume 6. It is provided in each case in the design variant according to FIGS. 6 to 8 for the first and the second stop 15, 16 to be placed in front of a continuous channel of a relief opening into the piston plate 9, with the result that the substantially cylindrical valve body 14a is guided in the manner of a clearance fit between the first and the second stop 15, 16 in a manner which is guided by the inner shell face of the channel in the piston plate 9.
[0047] FIGS. 9 to 11 show an alternative embodiment of a first stop 15. Here, the first stop 15 is formed by way of a shoulder in the channel of the piston plate 9. Merely the second stop 6 is provided by way of a discretely placed plate which can be dismantled in order to introduce the valve body 14a into its clearance fit. The function and method of operation are identical, however, to the design variant as shown in FIGS. 6, 7 and 8.
[0048] Starting from the piston plate 9, FIG. 12 shows a second design variant of a control valve 13b. Two identical control valves 13b are once again provided on the piston plate 9. The utilization of an elastically deformable valve body 14b is now provided. The elastically deformable valve body 14b once again has a cylindrical shape with a circular cross section. The valve body 14b of the second design variant of a control valve 13b is, however, positioned flatly on that side of the piston plate 9 which faces the compression volume 6. To this end, a central screw connection is provided, a relief opening with a plurality of channels being arranged in the piston plate 9 in the overlap region of the valve body 14b of the second design variant 13b, which relief opening is covered by the valve body 14b. On the basis of FIGS. 13 to 15, the method of operation of the control valve 13b in the second design variant is now to be described. During a switch-off operation and while the compression volume 6 is decreasing in size in the process, the flow pressure presses a valve body 14b of the second design variant of the control valve 13b against the wall (first stop 15) of the piston plate 9, and dams the channels in the piston plate 9. Therefore, in the case of a switch-off operation, the fluid which is situated in the compression volume 6 is pressed through the blowing channels 7 of the first switching contact pieces 3 in the direction of the switching path 2. In the case of a switch-on operation, a reversal of the direction of the flowing fluid takes place. On account of the elastic deformation capability of the valve body 14b of the second design variant, the flow pressure than presses said valve body 14b out of the sealing seat and lifts it on its free periphery from the piston plate 9. Held centrally by the second stop 16 and deformed elastically, fluid flows into the interior of the compression volume 6 via the channels in the piston plate 9. The valve body 14b of the control valve 13b in a second design variant is fixed in a punctiform manner by the second stop 16.
[0049] FIG. 16 shows a piston plate 9 with a control valve 13c in a third design variant. It is provided in the third design variant for an elastically deformable valve body 14c to be clamped in on one side (at the edge), with the result that flap-like opening of the valve body 14c of the control valve 13c in a third design variant is enabled. A second stop 16 which has a convexly curved stop face serves to fasten the valve body 14c in a punctiform manner. As a result, it is possible that the valve body 14c of the third control valve 13c lifts up from the first stop 15 which is formed by the surface of the piston plate 9, and presses against the second stop 16. Excessive deformation, or mechanical loading, for example notching of the valve body 14c of the control valve 13c in a third design variant, is prevented on account of the convex curvature of the second stop 16. FIGS. 17, 18, 19 show the method of operation of the control valve 13c in the third design variant, in a substantially identically acting manner to what is shown in FIGS. 13, 14 and 15. In the case of a switch-off operation, the compression volume 6 is reduced, whereupon a flow pressure presses the valve body 14c of the control valve 13c of the third design variant against the first stop 15, the valve body 14c completely covering and sealing a relief opening in the piston plate 9 (FIG. 17). The valve body 14c is pressed into its sealing position. In the case of a switch-on operation, an increase in the compression volume 6 occurs. Driven by the flow pressure, the valve body 14c of the control valve 13c in the third design variant is removed from the first stop 15 and is pressed against the second stop 16. Fluids can then flow over via the relief opening in the piston plate 9 into the interior of the compression volume 6.
