Cover for on-load tap changer

Abstract

- Cover element 1.1 having a first opening 1.5, - Aperture element 30, A load-operated tap changer cover 1, which includes, The throttling element 30 is located within the first opening 1.5 of the load-operated tap changer cover 1.

Description

Technical Field

[0001] The present invention relates to a load tap changer cover and a load tap changer device having the load tap changer cover.

Background Art

[0002] In order to appropriately respond to a suddenly occurring pressure increase, conventionally, a pressure relief valve has been used in electrical equipment such as a load tap changer and a transformer. However, such a pressure relief valve cannot always operate quickly, particularly when a failure is caused by high energy. As a result, there is a risk that the pressure relief valve may be damaged, and there is also a risk that the parts of the electrical equipment may be damaged.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Therefore, an object of the present invention is to provide a load tap changer cover that is easily formed, easily assembled, and provides a high level of safety and reliability even in the event of a high-energy failure.

Means for Solving the Problems

[0004] This problem is solved by the load tap changer cover according to claim 1. In this case, preferred embodiments of the present invention are described in the dependent claims. <)

[0005] Furthermore, an object of the present invention is to provide a load tap changer device that is easily formed, easily assembled, and provides a high level of safety and reliability even in the event of a high-energy failure.

[0006] This problem is solved by the load tap changer device according to claim 7. Preferred embodiments of the present invention are described in the dependent claims.

[0007] According to a first feature, the present invention - A cover element having a first opening, - Aperture element, We propose a load-operated tap changer cover that includes this feature.

[0008] In this case, the aperture element is located within the first aperture.

[0009] An on-load tap changer cover fitted with a throttling element provides a very simple and safe solution to address high-energy failures in on-load tap changers. Because the throttling element is located within the on-load tap changer cover, it can be very easily replaced or retrofitted to an on-load tap changer cover already installed on the on-load tap changer. The throttling element reduces the pressure generated within the on-load tap changer, preventing damage to the pressure relief valve fitted to the on-load tap changer, thereby preventing the insulating medium from reaching the surroundings uncontrollably.

[0010] Preferably, the on-load tap changer cover may have a cover element having a first opening. The cover element may be installed on top of the changer oil tank so as to seal the changer oil tank. Preferably, the cover element is formed as a disc. The on-load tap changer cover is connected to or screwed to the changer oil tank via the cover element using bolts or screws. The cover element may have further openings, for example, for a drive shaft or an oil filler or drain port.

[0011] Furthermore, the on-load tap changer may have a flange element positioned directly above the first opening within the cover element. A tubular element of this flange element is fitted and connected to the cover element. Preferably, the inner diameter of the tubular element is greater than or equal to the diameter of the first opening. By having a first opening with a diameter smaller than the inner diameter of the tubular element, the insulating medium is initially restricted when flow is passing through the on-load tap changer cover.

[0012] The aperture element can be formed in any manner, for example, as a fixed aperture element. Preferably, the aperture element is formed as a cylindrical cup, a trapezoidal cup, or a dome-shaped cup. More preferably, the aperture element is formed integrally.

[0013] The throttling element may have an annular wall, a bottom, and a second annular plate. The annular wall may have at least one, preferably two, three, or four through-holes. The bottom and through-holes in the annular wall of the throttling element throttle the insulating medium as it rises from the changeover switch oil tank through the first opening in the on-load tap changer cover, before it further reaches the pressure relief valve.

[0014] The under-load tap changer cover can be formed in any manner. In this case, - The aperture element has a ring groove, - The throttling element is fixed to the load tap changer cover by a snap ring in a ring groove and an annular plate.

[0015] Furthermore, the throttling element may be screwed, glued, soldered, or welded within the load tap changer cover. In this case, the two components may be optionally mated or press-fitted.

[0016] According to the second feature, the present invention is - An on-load tap changer having a changeover switch oil tank filled with an insulating medium, - Load-operated tap changer cover, - Aperture element, - Pressure relief valve, We propose a load-based tap-changing device that includes this feature.

[0017] in this case, - The aperture element is located inside the load tap changer cover. - The under-load tap changer cover is positioned between the changer oil reservoir and the pressure relief valve together with a throttling element, so that the flow of the insulating medium is restricted by the throttling element when there is a rapid increase in pressure in the changer oil reservoir.

[0018] The on-load tap changer provides a very high level of safety during operation. The throttle element within the on-load tap changer cover reduces the pressure generated within the on-load tap changer that may be caused by a high-energy failure in the switch disconnector oil tank or transformer. As a result, the normal function of the pressure relief valve is ensured. Therefore, the insulating medium inside the switch disconnector oil tank can be discharged during a failure or can reach the surroundings appropriately through the discharge pipe. Damage to individual elements due to very high pressure and uncontrolled scattering of these components are avoided. In the assembled state, the on-load tap changer cover is mounted on the switch disconnector oil tank of the on-load tap changer and seals this switch disconnector oil tank.

[0019] The throttle element is arranged in front of the pressure relief valve and is arranged within the on-load tap changer cover between the switch disconnector oil tank and the pressure relief valve. The throttle element is configured such that the residual and depressurized pressure in the insulating medium 10 behind this throttle element still reliably operates the pressure relief valve without damaging the pressure relief valve.

[0020] The on-load tap changer can be configured in any manner, for example, it can be arranged on the on-load tap changer cover and can have at least one casing connected to this on-load tap changer cover. Preferably, the casing and the on-load tap changer cover are screwed or riveted to the housing of the transformer.

[0021] The casing is used to further strengthen and reinforce the on-load tap changer cover in the event of a failure occurring within the switch disconnector oil tank.

[0022] The casing can be formed in various ways, for example, integrally or from multiple parts. The combination consisting of the casing and the throttle element provides a very safe and highly reliable device that can withstand high pressure during a failure.

[0023] Preferably, the casing and the on-load tap-changer cover are screwed, riveted, adhered, welded or soldered to each other and are screwed, riveted, adhered, welded or soldered to the housing of the transformer.

[0024] The present invention and its advantages will be described in detail below with reference to the accompanying drawings.

Brief Description of the Drawings

[0025] [Figure 1] Shows a transformer having an on-load tap-changer. [Figure 2a] Shows an on-load tap-changer cover. [Figure 2b] Shows a cross-section of the on-load tap-changer cover. [Figure 3] Shows a throttle element. [Figure 4] Shows a cross-section of the on-load tap-changer cover with the throttle element arranged. [Figure 5] Shows another cross-section of the on-load tap-changer cover with the throttle element arranged.

Modes for Carrying Out the Invention

[0026] FIG. 1 shows a transformer 2 having an on-load tap-changer 3. In this case, the on-load tap-changer 3 is arranged inside the transformer 2. The transformer 2 has a housing composed of a bottom 2.3, a wall 2.1 and a cover 2.3. The on-load tap-changer 3 may have a switch disconnector and a selector or may be configured as a load selector. Further, the on-load tap-changer 3 has a switch disconnector oil tank 20, in which a section of the switch disconnector is arranged. Both the on-load tap-changer 3, particularly the switch disconnector oil tank 20 of this on-load tap-changer 3, and the transformer 2 are filled with an insulating medium 10. In the embodiment shown here, the insulating medium 10 in the transformer 2 does not contact the insulating medium 10 in the on-load tap-changer 3 and does not mix with each other. However, another embodiment may allow or enable mixing.

[0027] The insulating medium 10 may be a natural or artificial insulating medium such as mineral oil-based insulating oil or ester. The on-load tap changer 3 is fixed to the cover 2.3 of the transformer 2. The changeover switch oil tank 20 is sealed by the on-load tap changer cover 1. In this case, the on-load tap changer cover 1 is joined to the cover 2.3 of the transformer 2. A pressure relief valve 12 is installed on the outside of the on-load tap changer cover 1 via a flange element 1.2. In this embodiment, the pressure relief valve 12 is connected to the discharge pipe 16.

[0028] The pressure relief valve 12 is configured and installed to release pressure in the on-load tap changer oil tank 20 of the on-load tap changer 3 when pressure rises due to a malfunction or failure. In this case, the pressure generated inside the on-load tap changer 3, particularly inside the on-load tap changer oil tank 20, is released to the surroundings through the on-load tap changer cover 1 and the pressure relief valve 12 located on top of it, without damaging the transformer 2, the on-load tap changer 3, or other components. Specifically, in the event of a failure, an electric arc is generated in the on-load tap changer 3, causing a large current to flow between the electrodes. The gas generated by the high-pressure arc is pushed out to the outside as a pressure wave due to the pressure difference with the surroundings. Depending on the energy and location of the failure, the pressure relief valve 12 performs its release operation before the pressure rises too high, avoiding failure of critical components that could, in extreme cases, damage the on-load tap changer 3 or the transformer 1. Conventional pressure relief valves are not designed for pressure relief in such high-energy failure situations.

[0029] During normal operation of the on-load tap changer 3, the pressure relief valve 12 is closed. In this first state, the pressure in the changeover switch oil tank 20 is within a predetermined limit. In this first state, the volume of insulating medium 10 present in the changeover switch oil tank 20 of the on-load tap changer 3 does not exceed a preset amount of this volume.

[0030] The throttle element 30, which is attached to the under-load tap changer cover 1, reduces the pressure generated in the event of a failure involving a very high energy content and a steep pressure rise. This prevents potential damage to the pressure relief valve 12 due to pressure waves.

[0031] The throttling element 30 is positioned in front of the pressure relief valve 12 and is installed in the load tap changer cover 1 between the changeover switch oil tank 20 and the pressure relief valve 12. In this case, the throttling element 30 is configured so that the residual and reduced pressure in the insulating medium 10 behind the throttling element 30 still reliably operates the pressure relief valve 12, but does not damage the pressure relief valve 12.

[0032] Furthermore, an on-load tap changing device 40 is shown, which includes an on-load tap changer 3, an on-load tap changer cover 1, a throttling element 30, and a pressure relief valve 12.

[0033] In the context of this invention, the on-load tap changer cover 1 can also be considered a transformer cover. In this case, the corresponding transformer cover also has an opening with a throttling element incorporated therein. In this case as well, the throttling element is connected in front of the pressure relief valve 12. In this case, the throttling element suppresses the pressure rise in the insulating medium of the transformer that occurs within the transformer, thereby preventing damage to the pressure relief valve. The transformer cover may have a flange with an annular plate above the throttling element to secure the pressure relief valve.

[0034] The flow resistance generated by the throttling element is designed to allow the pressure relief valve 12 to operate or function without being damaged in the event of a high-energy failure.

[0035] Figures 2a and 2b show an on-load tap changer cover 1. This on-load tap changer cover 1 has a cover element 1.1 formed as a substantially circular disc. The cover element 1.1 has a first opening 1.5 that extends from a first surface of the cover element 1.1 to an opposing second surface of the cover element 1.1. Preferably, the first opening 1.5 is formed in a circular shape and has a predetermined cross-section. The first opening 1.5 can be located at any position within the cover element 1.1, but preferably it does not have to be located in the center. Directly above the first opening 1.5, a flange element 1.2 is positioned on the cover element 1.1. The flange element 1.2 has a tubular element 1.3 and a first annular plate 1.4. The first end of the tubular element 1.3 is connected to the first annular plate 1.4. The second end of the tubular element 1.3 is fitted and connected to the cover element 1.1. A cover element 1.1, a flange element 1.2 having a tubular element 1.3, and a first annular plate 1.4 are formed as cast parts. In this case, the inner cross-section or diameter of the tubular element 1.3 is larger than the cross-section of the first opening 1.5.

[0036] Figure 3 is a detailed view of the aperture element 30. The aperture element 30 is fitted into the opening 1.5 of the on-load tap changer cover 1 in its assembled state. In this embodiment, the aperture element 30 is formed as a cylindrical cup. Furthermore, the aperture element 30 may be formed as a trapezoidal cup or a dome-shaped cup. The aperture element 30 has a circumferential annular wall 32. The annular wall 33 has a bottom 33 at its first end 32.1. At the second end 32.2, which is positioned opposite the first end 32.1, the aperture element 30 is open and has an aperture hole 35. At the second end 32.2 of the annular wall 32, a ring groove 38 and a second annular plate 39 are fitted into or formed on the outer surface 37 of the annular wall 32. The outer diameter of the second end 32.2 of the annular wall 32 is approximately the same as the diameter of the first opening 1.5 of the on-load tap changer cover 1. In the assembled state, the throttling element 30 is fitted into the first opening 1.5 of the on-load tap changer cover 1 or connected to the on-load tap changer cover 1. In this embodiment, the throttling element 30 is fixed to the first opening 1.5 of the on-load tap changer cover 1 via a ring groove 38 and a second annular wall 39 by a snap ring (not shown herein). In the assembled state, the throttling hole 35 forms the first opening 1.5 of the on-load tap changer cover 1. Furthermore, the annular wall 32 has at least one opening or through-hole 34. In the embodiment shown herein, the annular wall 32 has four through-holes 34 evenly distributed in the annular wall 32. In this embodiment, the throttling element 30 is formed as a fixed throttling valve having a certain cross-sectional narrowing portion.

[0037] Figure 4 is a cross-sectional view of the on-load tap changer cover 1 having a fitted throttling element 30. In this case, the throttling element 30 is fitted into or connected to the on-load tap changer cover 1 in the first opening 1.5 of the on-load tap changer cover 1. In the assembled state, the throttling element 30 protrudes into the tubular element 1.3 of the flange element 1.2, i.e., toward the pressure relief valve 12. The dashed arrow 29 indicates the possible flow of the insulating medium 10 out of the on-load tap changer 3, particularly from the changer oil tank 20. In this case, the pressure relief valve 12 is also connected to a discharge pipe 16 that guides or deflects the flow of the insulating medium 10 outwards. The insulating medium 10 flows into the interior of the throttling element 30 through the first opening 1.5, particularly the throttling hole 35, when it flows out of the changer oil tank 20. This causes the flow to be initially throttled. Here, the insulating medium 10 is throttled or braked, particularly by the bottom 33. Furthermore, the insulating medium 10 is further constricted through the through-hole 34 in the annular wall 32 when it flows out from the throttling element 30.

[0038] Figure 5 is a cross-sectional view of the on-load tap changer cover 1 having a fitted throttling element 30. The throttling element 30 is fitted into or connected to the on-load tap changer cover 1. Arrow 29 indicates a possible flow of insulating medium 10 from the on-load tap changer 3 to the outside. Furthermore, two casings 8, configured to reinforce and stabilize the on-load tap changer cover 1, are arranged on the on-load tap changer cover 1. In this case, the casings 8 can cover all or part of the on-load tap changer cover 1 and thus be reinforced, or they may be formed as a single casing 8, or in another embodiment, they may be formed from two or more members. The casings 8 may be formed, for example, as a metal arc or bow-shaped plate. The combination of the casings 8 and the on-load tap changer cover 1 with the throttling element 30 provides a particularly safe and reliable on-load tap changer 40. This configuration ensures that the pressure relief valve 12 functions properly in the event of a high-energy failure in the on-load tap changer 3 or transformer 1. Individual components are prevented from detaching and scattering into the surroundings, and thus the insulating medium 10 is prevented from reaching the surroundings uncontrollably. The casing 8 is screwed to the on-load tap changer 3 and / or transformer housing together with the on-load tap changer cover 1. [Explanation of Symbols]

[0039] 1. Tap changer cover under load 1.1 Cover elements 1.2 Flange elements 1.3 Tubular elements 1.4 First Ring Plate 1.5 First opening 2 Transformers 2.1 Wall 2.2 Bottom 2.3 Cover 3. Tap changer under load 8 Casing 10 Insulating medium 12 Pressure relief valve 16 Discharge pipe 20 Switch switch oil tank 30 aperture elements 32 Ring Wall 32.1 First end 32.2 Second end 33 Bottom 34 Through-hole 35 aperture holes 37 Exterior 38 Ring grooves 39 Second Ring Plate 40. On-load tap changer

Claims

1. - A cover element (1.1) having a first opening (1.5), - Aperture element (30), A load-operated tap changer cover (1) including, The throttle element (30) is located within the first opening (1.5) of the load-operated tap changer cover (1).

2. - A flange element (1.2) having a tubular element (1.3) formed directly above the first opening (1.5) is provided. - The inner diameter of the tubular element (1.3) is greater than the diameter of the first opening (1.5). The load-operated tap changer cover (1) described in claim 1

3. - The aperture element (30) is formed as a fixed aperture element (30). The load-operated tap changer cover (1) according to claim 1 or 2.

4. - The aperture element (30) is formed as a cylindrical cup, a trapezoidal cup, or a dome-shaped cup. A load-operated tap changer cover (1) according to any one of claims 1 to 3.

5. - The aperture element (30) has an annular wall (32), a bottom (33), and a second annular plate (39), - The annular wall (32) has at least one through-hole (34), A load-operated tap changer cover (1) according to any one of claims 1 to 4.

6. - The aperture element (30) has a ring groove (38), - The diaphragm element (30) is fixed to the load tap changer cover (1) by a snap ring in the ring groove (38) and the annular plate (39). A load-operated tap changer cover (1) according to any one of claims 1 to 5.

7. - An on-load tap changer (3) having a changeover switch oil tank (20) filled with an insulating medium (10), - Load-operated tap changer cover (1), - Aperture element (30), - Pressure relief valve (12), A load-operated tap-changing device (40) including, - The aperture element (30) is located inside the load tap changer cover (1), - The on-load tap changer cover (1) is positioned together with a throttling element (30) between the changeover switch oil tank (20) and the pressure relief valve (12), and the on-load tap changer (40) is such that the flow of the insulating medium (10) is restricted by the throttling element (30) when there is a rapid increase in pressure in the changeover switch oil tank (20).

8. - An on-load tap changer (40) according to claim 7, comprising at least one casing (8) positioned on and connected to the on-load tap changer cover (1).

9. - The on-load tap changer (40) according to claim 8, wherein the casing (8) and the on-load tap changer cover (1) are screwed or riveted to the housing of the transformer (2).

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