On-load tap changer cover and on-load tap changer device

Abstract

The invention relates to an on-load tap-changer cover (1), comprising: - a cover element (1.1) having a first opening (1.5), and - a throttle element (30); wherein - the throttle element (30) is arranged in the first opening (1.5).

Description

[0001] On-load tap-changer cover and on-load tap-changer device

[0002] The invention relates to an on-load tap-changer cover and an on-load tap-changer device with an on-load tap-changer cover.

[0003] Pressure relief valves have always been used in electrical equipment such as on-load tap-changers and transformers to adequately respond to sudden pressure surges. However, these cannot always react quickly enough, especially in the case of high-energy faults, which can lead to the destruction of the pressure relief valve and even parts of the equipment.

[0004] The object of the invention is therefore to provide an on-load tap-changer cover which is simple in design and easy to install, while offering a high degree of safety and reliability in the event of high-energy faults.

[0005] This object is achieved by an on-load tap-changer cover according to claim 1. The subclaims form advantageous embodiments of the invention.

[0006] A further object of the invention is to provide an on-load tap-changer device which is of simple construction and provides a high degree of safety and reliability in the event of high-energy faults.

[0007] This object is achieved by an on-load tap-changer device according to claim 7. The subclaims form advantageous embodiments of the invention.

[0008] According to a first aspect, the invention proposes an on-load tap-changer cover, comprising: a cover element having a first opening, a throttle element; wherein the throttle element is arranged in the first opening.

[0009] The on-load tap-changer cover with the integrated throttle element provides a particularly simple and safe solution for responding to high-energy faults in an on-load tap-changer. Because the throttle element is located in the on-load tap-changer cover, an already installed on-load tap-changer cover can be easily replaced or retrofitted with a new one. The throttle element reduces the pressure built up in the on-load tap-changer and prevents a pressure relief valve attached to the on-load tap-changer from being destroyed, which could result in the uncontrolled release of insulating medium into the environment.

[0010] The on-load tap-changer cover can preferably have a cover element in which a first opening is provided. The cover element is designed such that it can be placed on the head of a diverter switch vessel, thereby closing it. The cover element is preferably designed as a circular disc. The on-load tap-changer cover is connected or screwed to the diverter switch vessel via the cover element using bolts or screws. The cover element can also have further openings, for example, for a drive shaft or oil intake or oil extraction nozzles.

[0011] Furthermore, the on-load tap-changer cover can have a flange element arranged directly above the first opening in the cover element. A tubular element of the flange element is positively connected to the cover element. The inner diameter of the tubular element is preferably greater than or equal to the diameter of the first opening. Because the first opening has a smaller diameter than the inner diameter of the tubular element, an initial throttling of the insulating medium is already created at this point as it flows through the on-load tap-changer cover.

[0012] The throttle element can be designed in any desired manner, for example, as a static throttle element. Preferably, this is designed as a cylindrical cup, a truncated cone cup, or even a dome-shaped cup. Furthermore, the throttle element is preferably formed as a single piece.

[0013] The throttle element can have an annular wall, a base part, and a second annular disc. The annular wall can have at least one, preferably two, three, or four, openings. The base part and the openings in the annular wall of the throttle element throttle the insulating medium as it rises from the diverter switch vessel through the first opening in the on-load tap-changer cover before it then continues to the pressure relief valve.

[0014] The on-load tap-changer cover can be designed in any desired manner, with the throttle element having an annular groove; the throttle element is fastened to the on-load tap-changer cover by means of a snap ring in the annular groove and the annular disc.

[0015] Furthermore, the choke element can be screwed, glued, soldered, or welded into the on-load tap-changer cover. This can involve any form-fitting or force-fitting connection between the two parts.

[0016] According to a second aspect, the invention proposes an on-load tap-changer device, comprising: an on-load tap-changer with a diverter switch vessel filled with an insulating medium, an on-load tap-changer cover; a throttle element; a pressure relief valve; wherein the throttle element is arranged in the on-load tap-changer cover; the on-load tap-changer cover with the throttle element is arranged between the diverter switch vessel and the pressure relief valve, and a flow of the insulating medium is throttled by the throttle element in the event of a rapid pressure increase in the diverter switch vessel.

[0017] The on-load tap-changer device offers a particularly high degree of safety during operation. The throttling element in the on-load tap-changer cover reduces the pressure that can arise in the on-load tap-changer due to high-energy faults in the diverter switch vessel or transformer, thus ensuring the proper functioning of the pressure relief valve. In the event of a fault, the insulating medium inside the diverter switch vessel can thus escape in a controlled manner or be directed into the atmosphere via a drain pipe. The destruction of individual components due to excessive pressure, as well as the uncontrolled flying of these parts, is prevented. The on-load tap-changer cover is attached to the diverter switch vessel of the on-load tap-changer when installed and seals it.

[0018] The throttle element is connected upstream of the pressure relief valve and is located in the on-load tap-changer cover between the diverter switch compartment and the pressure relief valve. The throttle element is designed such that the remaining and reduced pressure in the insulating medium downstream of the throttle element still allows the pressure relief valve to respond reliably, but is reduced to such an extent that the pressure relief valve is not damaged. The on-load tap-changer can be designed in any desired manner and, for example, can have at least one casing arranged on and connected to the on-load tap-changer cover. The casing and the on-load tap-changer cover are preferably screwed or riveted to the transformer housing.

[0019] The casing also serves as additional reinforcement and support for the on-load tap-changer cover in the event of a fault in the on-load tap-changer vessel.

[0020] The casing can be designed in different ways, for example, as a single piece or multiple pieces. The combination of casing and throttle element creates a particularly safe and reliable device that can withstand the high pressures in the event of a failure.

[0021] The casing and the on-load tap-changer cover are preferably screwed, riveted, glued, soldered, or welded to each other and to the transformer housing. This can be any form-fitting or force-fitting connection between the two parts.

[0022] The invention and its advantages are described in more detail below with reference to the accompanying drawings. They show:

[0023] Figure 1 shows a transformer with an on-load tap changer;

[0024] Figures 2a and 2b show an on-load tap-changer cover and a sectional view of the on-load tap-changer cover;

[0025] Figure 3 a throttle element;

[0026] Figure 4 shows a sectional view of the on-load tap-changer cover with inserted

[0027] throttle element;

[0028] Figure 5 shows another sectional view of the on-load tap-changer cover with inserted

[0029] Throttle element.

[0030] Figure 1 shows a transformer 2 with an on-load tap-changer 3. The on-load tap-changer 3 is arranged inside the transformer 2. The transformer 2 has a housing which consists of a base part 2.2, walls 2.1 and a cover 2.3. The on-load tap-changer 3 can have a diverter switch and a selector or can be designed as a load selector. The on-load tap-changer 3 further has a diverter switch vessel 20 in which a diverter switch insert is arranged. Both the on-load tap-changer 3, and in particular its diverter switch vessel 20, and the transformer 2 are filled with an insulating medium 10. In the exemplary embodiment shown here, the insulating medium 10 in the transformer 2 has no contact with the insulating medium 10 in the on-load tap-changer 3; there is no exchange between them. However, alternative embodiments can enable or comprise an exchange.

[0031] The insulating medium 10 can be a natural or artificial insulating medium, such as a mineral insulating oil or ester. The on-load tap-changer 3 is attached to the cover 2.3 of the transformer 2. The diverter switch vessel 20 is closed with an on-load tap-changer cover 1. The on-load tap-changer cover 1 adjoins the cover 2.3 of the transformer 1. A pressure relief valve 12 is attached to 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 a drain pipe 16.

[0032] The pressure relief valve 12 is designed and configured to relieve pressure in the diverter switch vessel 20 of the on-load tap-changer 3 in the event of pressure increases due to faults or malfunctions. The pressure generated inside the on-load tap-changer 3, or in particular the pressure generated inside the diverter switch vessel 20, is released to the environment via the on-load tap-changer cover 1 and the pressure relief valve 12 arranged thereon. Pressurized insulating medium 10 and air can be discharged without damaging the transformer 2, the on-load tap-changer 3, or other parts. In detail, in the event of a fault, an electric arc is generated in the on-load tap-changer 3, leading to a high current flow between the electrodes. The gas generated in the arc under high pressure is forced outward by a pressure wave due to the pressure difference to the environment.Depending on the fault energy and fault location, a pressure relief valve 12 can provide pressure relief before the pressure rises too high and critical components fail, which in extreme cases can lead to the destruction of the on-load tap-changer 3 or the transformer 1. Existing pressure relief valves are not designed to relieve pressure during such high-energy faults.

[0033] 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 diverter switch vessel 20 is within a predetermined limit. The volume of the insulating medium 10 located in the diverter switch vessel 20 of the on-load tap-changer 3 does not exceed its predetermined amount in this first state.

[0034] A throttle element 30, which is mounted in the on-load tap-changer cover 1, ensures that in the event of faults with very high energy content and a steep pressure increase, the resulting pressure is reduced, thereby preventing possible destruction of the pressure relief valve 12 by a pressure wave.

[0035] The throttle element 30 is connected upstream of the pressure relief valve 12 and is located in the on-load tap-changer cover 1 between the diverter switch vessel 20 and the pressure relief valve 12. The throttle element 30 is designed such that the remaining and reduced pressure in the insulating medium 10 downstream of the throttle element 30 still allows the pressure relief valve 12 to respond reliably, but is reduced to such an extent that the pressure relief valve 12 is not damaged.

[0036] Furthermore, an on-load tap-changer device 40 is shown, which comprises the on-load tap-changer 3, the on-load tap-changer cover 1, the throttle element 30 and the pressure relief valve 12.

[0037] For the purposes of the invention, a transformer cover is also understood as an on-load tap-changer cover 1. A corresponding transformer cover also has an opening with a throttle element incorporated therein. The throttle element is then also connected upstream of a pressure relief valve. The throttle element then throttles a pressure increase in the transformer's insulating medium, thus preventing the pressure relief valve from being destroyed. The transformer cover can have a corresponding flange with an annular disc for attaching the pressure relief valve above the throttle element.

[0038] The flow resistance generated by the throttle element is designed so that the pressure relief valve 12 can act and function non-destructively in the event of a high-energy fault.

[0039] Figures 2a and 2b show an on-load tap-changer cover 1. This has a cover element 1.1 designed essentially as a round disk. A first opening 1.5 is arranged in the cover element 1.1, which extends from a first side of the cover element 1.1 to a second, opposite side of the cover element 1.1. The first opening 1.5 is preferably circular and has a defined cross-section. The first opening 1.5 can be arranged at any location in the cover element 1.1, but preferably not in the center. A flange element 1.2 is arranged on the cover element 1.1 directly above the first opening 1.5. The flange element 1.2 has a tubular element 1.3 and a first annular disk 1.4. The first end of the tubular element 1.3 is connected to the annular disk 1.4. The second end of the tubular element 1.3 is positively connected to the cover element 1.1. The cover element 1.1, the flange element 1.2 with the pipe element 1.3 and the first annular disc 1.4 are designed as a single cast part. The inner cross-section or diameter of the tubular element 1.3 is larger than the cross-section of the first opening 1.5.

[0040] Figure 3 shows a detailed view of the throttle element 30. The throttle element 30 is mounted in the opening 1.5 of the on-load tap-changer cover 1. In this embodiment, the throttle element 30 is designed as a cylindrical cup. Furthermore, the throttle element 30 can also be designed as a frustoconical cup or as a dome-shaped cup. The throttle element 30 has a circumferential annular wall 32, which has a base part 33 at its first end 32.1. At a second end 32.2, which is arranged opposite the first end 32.1, the throttle element 30 is open and has a throttle opening 35. At the second end 32.2 of the annular wall 32, an annular groove 38 and a second annular disk 39 are introduced or formed on an outer surface 37 of the annular wall 32. The outer diameter at the second end 32.2 of the annular wall 32 essentially corresponds to the diameter of the first opening 1.5 of the on-load tap-changer cover 1.In the assembled state, the throttle element 30 is inserted into the first opening 1.5 of the on-load tap-changer cover 1 or connected thereto. In this embodiment, the throttle element 30 is fastened in the first opening 1.5 of the on-load tap-changer cover 1 by means of a snap ring (not shown here) via the annular groove 38 and the second annular disk 39. In the assembled state, the throttle opening 35 forms the first opening 1.5 of the on-load tap-changer cover 1. The annular wall 32 also has at least one opening or opening 34. In the embodiment shown here, the annular wall 32 has four openings 34 that are evenly distributed in the annular wall 32. In this embodiment, the throttle element 30 is designed as a static throttle with a constant cross-sectional constriction.

[0041] Figure 4 shows a sectional view of the on-load tap-changer cover 1 with the throttle element 30 inserted. The throttle element 30 is inserted into the first opening 1.5 of the on-load tap-changer cover 1 or connected to it. In the assembled state, the throttle element 30 projects into the pipe element 1.3 of the flange element 1.2, i.e., towards the pressure relief valve 12. The dotted arrow 29 shows a possible flow of the insulating medium 10 from the on-load tap-changer 3 and, in particular, the diverter switch vessel 20 to the outside. A drain pipe 16 can also be connected to the pressure relief valve 12, which controls or diverts the flow of the insulating medium 10 to the outside. Upon leaving the diverter switch vessel 20, the insulating medium 10 flows through the first opening 1.5, in particular, the throttle opening 35, into the interior of the throttle element 30, thereby initially throttling the flow. Here, the insulating medium 10 is throttled or restricted by, among other things, the base part 33.braked. Furthermore, the insulating medium 10 is further throttled upon leaving the throttle element 30 through the openings 34 in the annular wall 32.

[0042] Figure 5 shows a sectional view of the on-load tap-changer cover 1 with the throttle element 30 inserted. The throttle element 30 is inserted into the first opening 1.5 of the on-load tap-changer cover 1 or connected to it. The arrow 29 shows a possible flow of the insulating medium 10 from the on-load tap-changer 3 to the outside. Furthermore, two casings 8 are arranged on the on-load tap-changer cover 1, which are designed to reinforce the on-load tap-changer cover 1 and make it more stable. The casings 8 can cover the entire on-load tap-changer cover 1 or only parts thereof and thus reinforce it, or can also be designed as a one-piece casing 8 or, in other embodiments, consist of more than two parts. The casings 8 can, for example, be designed as crescent-shaped or arc-shaped metal plates.The combination of casings 8 and an on-load tap-changer cover 1 with a throttle element 30 creates a particularly safe and reliable on-load tap-changer device 40. This design ensures that the pressure relief valve 12 functions properly in the event of high-energy faults in the on-load tap-changer 3 or transformer 1. This prevents individual parts from breaking off and being ejected into the environment, thus preventing the insulating medium 10 from entering the environment in an uncontrolled manner. The casings 8 are screwed onto the on-load tap-changer cover 1 and / or the transformer housing.

[0043] List of reference symbols

[0044] 1 on-load tap-changer cover

[0045] 1.1 Cover element

[0046] 1.2 Flange element

[0047] 1.3 Pipe element

[0048] 1.4 first ring disc

[0049] 1.5 first opening

[0050] 2 transformer

[0051] 2.1 Wall

[0052] 2.2 Base part

[0053] 2.3 Lid

[0054] 3 on-load tap-changers

[0055] 8 Formwork

[0056] 10 Insulating medium

[0057] 12 Pressure relief valve

[0058] 16 Drain pipe

[0059] 20 diverter switch vessel

[0060] 30 throttle element

[0061] 32 ring wall

[0062] 32.1 first end

[0063] 32.2 second end

[0064] 33 Base part

[0065] 34 Breakthrough

[0066] 35 Throttle opening

[0067] 37 exterior area

[0068] 38 ring groove

[0069] 39 second ring disc

[0070] 40 On-load tap-changer device

Claims

Patent claims 1. On-load tap-changer cover (1), comprising: a cover element (1.1) with a first opening (1.5), a throttle element (30); wherein the throttle element (30) is arranged in the first opening (1.5).

2. On-load tap-changer cover (1) according to claim 2, wherein a flange element (1.2) is provided with a tubular element (1.3) which is formed directly above the first opening (1.5); an inner diameter of the tubular element (1.3) is larger than a diameter of the first opening (1.5).

3. On-load tap-changer cover (1) according to one of claims 1-2, wherein the throttle element (30) is designed as a static throttle element (30).

4. On-load tap-changer cover (1) according to one of claims 1-3, wherein the throttle element (30) is designed as a cylindrical cup, as a truncated cone-shaped cup or as a dome-shaped cup.

5. On-load tap-changer cover (1) according to one of claims 1-4, wherein the throttle element (30) has an annular wall (32), a base part (33), and a second annular disc (39); the annular wall (32) has at least one through-hole (34).

6. On-load tap-changer cover (1) according to one of claims 1-5, wherein the throttle element (30) has an annular groove (38); the throttle element (38) is fastened to the on-load tap-changer cover (1) by means of a snap ring in the annular groove (38) and the annular disc (39).

7. On-load tap-changer device (40), comprising: an on-load tap-changer (3) with a load diverter switch vessel (20) which is provided with a Insulating medium (10) is filled, an on-load tap-changer cover (1); a throttle element (30); a pressure relief valve (12), wherein the throttle element (30) is arranged in the on-load tap-changer cover (1); the on-load tap-changer cover (1) with the throttle element (30) is arranged between the load diverter switch vessel (20) and the pressure relief valve (12), and a flow of the insulating medium (10) is throttled by the throttle element (30) in the event of a rapid pressure increase in the load diverter switch vessel (20).

8. On-load tap-changer device (40) according to claim 7, comprising at least one casing (8) which is arranged on the on-load tap-changer cover (1) and connected thereto.

9. On-load tap-changer device (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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