FLANGE FOR AN ELECTRICAL BUSHING AND ELECTRICAL BUSHING

Abstract

A flange for an electrical bushing is specified, comprising a lower part and an upper part configured to be mechanically affixed to one another, wherein the lower part and the upper part are arranged one above the other in an axial direction of the flange, and one of the lower part and the upper part surrounds a portion of the other one of the lower part and the upper part at least in regions in a radial direction, thereby forming a positive connection against relative movement of the upper part with respect to the lower part in a non-axial direction of the flange.

Furthermore, an electrical bushing is specified.

Claims

1-13. (canceled)

14. An electrical bushing comprising a flange and a core that extends through the flange, wherein: the flange comprises a lower part and an upper part configured to be mechanically affixed to one another, the lower part provides a mounting face and mounting holes for mounting the bushing to an electrical appliance, the lower part comprises a seat configured to mechanically support the core, the lower part and the upper part are arranged one above the other in an axial direction of the flange, and one of the lower part and the upper part surrounds a portion of the other one of the lower part and the upper part at least in regions in a radial direction, thereby forming a positive connection against relative movement of the upper part with respect to the lower part in a non-axial direction of the flange.

15. The electrical bushing according to claim 14, wherein the lower part of the flange comprises a mounting face configured for mounting the flange to an appliance.

16. The electrical bushing according to claim 15, wherein the upper part and the lower part are affixed to one another along a connection plane running in parallel to the mounting face, wherein the lower part comprises an elevation, wherein the elevation surrounds the upper part or the upper part surrounds the elevation on a side of the connection plane that faces away from the mounting face.

17. The electrical bushing according to claim 16, wherein the elevation comprises an annular portion extending along the upper part.

18. The electrical bushing according to claim 17, wherein the elevation further comprises a plurality of ribs mechanically supporting the annular portion on a side of the annular portion facing away from the upper part of the flange.

19. The electrical bushing according to claim 17, wherein the upper part overlaps with the elevation when seen along the axial direction.

20. The electrical bushing according to claim 14, wherein the positive connection is configured as a clearance fit or a transition fit.

21. The electrical bushing according to claim 14, wherein the positive connection is configured as an interference fit.

22. The electrical bushing according to claim 14, wherein the upper part comprises an indentation configured to receive an end part of an insulator.

23. The electrical bushing according to claim 14, wherein at least one of the upper part and the lower part is configured for a sealed connection between the lower part and the upper part.

24. The electrical bushing according to claim 14, wherein the flange is configured to receive a wiper extending around the upper part and covering at least part of the lower part when seen along the axial direction.

25. The electrical bushing according to claim 14, wherein the bushing is a capacitance graded bushing.

26. The electrical bushing according to claim 14, wherein the electrical bushing is configured for voltages between 3.6 kV and 1200 kV.

27. An electrical bushing comprising a flange and a core that extends through the flange, wherein: the flange comprises a lower part and an upper part configured to be mechanically affixed to one another, the lower part provides a mounting face and mounting holes for mounting the bushing to an electrical appliance, the lower part comprises a seat configured to mechanically support the core, the lower part and the upper part are arranged one above the other in an axial direction of the flange, and one of the lower part and the upper part surrounds a portion of the other one of the lower part and the upper part at least in regions in a radial direction, thereby forming a positive connection against relative movement of the upper part with respect to the lower part in a non-axial direction of the flange, wherein the positive connection is configured as an interference fit, and wherein the upper part comprises an indentation configured to receive an end part of an insulator.

28. The electrical bushing according to claim 27, wherein the lower part of the flange comprises a mounting face configured for mounting the flange to an appliance.

29. The electrical bushing according to claim 28, wherein the upper part and the lower part are affixed to one another along a connection plane running in parallel to the mounting face, wherein the lower part comprises an elevation, wherein the elevation surrounds the upper part or the upper part surrounds the elevation on a side of the connection plane that faces away from the mounting face.

30. The electrical bushing according to claim 29, wherein the elevation comprises an annular portion extending along the upper part.

31. The electrical bushing according to claim 30, wherein the elevation further comprises a plurality of ribs mechanically supporting the annular portion on a side of the annular portion facing away from the upper part of the flange, and wherein the upper part overlaps with the elevation when seen along the axial direction.

32. The electrical bushing according to claim 27, wherein the positive connection is configured as a clearance fit or a transition fit.

33. The electrical bushing according to claim 27, wherein at least one of the upper part and the lower part is configured for a sealed connection between the lower part and the upper part.

34. The electrical bushing according to claim 27, wherein the electrical bushing is configured for voltages between 3.6 kV and 1200 kV.

Description

[0033] In the figures:

[0034] FIG. 1 shows a schematic perspective cutaway view of an exemplary embodiment of a flange according to an example embodiment;

[0035] FIG. 2 shows a schematic sectional view of an electrical bushing according to an example embodiment;

[0036] FIG. 3. shows a schematic sectional view of an electrical bushing according to a further example embodiment; and

[0037] FIG. 4. shows a schematic sectional view of an electrical bushing according to a further example embodiment.

[0038] In the example embodiments and figures similar or similarly acting constituent parts are provided with the same reference signs. Generally, only the differences with respect to the individual embodiments may be described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0039] The elements illustrated in the figures and their size relationships among one another are not necessarily true to scale. Rather, individual elements or layer thicknesses may be represented with an exaggerated size for the sake of better representability and/or for the sake of better understanding.

[0040] In FIG. 1 an example embodiment of a flange 2 is illustrated in a perspective cutaway view. The flange 2 comprises a lower part 21 and an upper part 22. The lower part 21 forms a mounting face 20 for mounting the flange 2 to an appliance, for instance to a corresponding flange of the appliance.

[0041] The flange 2, for example the lower part 21 and the upper part 22 may be made from a metal or a metal alloy, for instance from an aluminum alloy or stainless steel.

[0042] The lower part 21 and the upper part 22 of the flange are arranged one above the other in an axial direction of the flange (y direction in FIG. 1, axis 10 in FIGS. 2 through 4).

[0043] The lower part 21 surrounds a portion of the upper part 22 of the flange 2, thereby forming a positive connection 24 against relative movement of the upper part 22 with respect to the lower part 21 in a non-axial direction of the flange 2.

[0044] Along the axial direction the lower part 21 and the upper part 22 directly adjoin each other at a connection plane 25 extending in parallel to the mounting face 20. A bolted joint which may be a sealing joint between the lower part 21 and the upper part 22 is formed at the connection plane 25. When seen along the axial direction towards the mounting face 20, the upper part 22 does not extend beyond the connection plane 25 at any position.

[0045] With respect to the connection plane 25 the lower part 21 comprises an elevation 23. In the example embodiment shown, the elevation 23 is formed by an annular portion 231. The extension of the elevation 23 in axial direction may be small compared to that of the upper part 22, for instance at most 30% or at most 20% and/or at least 1% or at least 5%.

[0046] An inner wall 271 of elevation 23 directly adjoins an outer wall 272 of the upper part 22 to form the positive connection 24.

[0047] The lower part 21 with the elevation 23 may be formed in one piece. The lower part 21 and/or the upper part 22 may be formed by casting, for instance.

[0048] The lower part 21 further comprises ribs 232 arranged on that side of the annular portion 231 that faces away from the inner wall 271. Of course, the shape of the elevation 23 may be modified in wide ranges, as long as a positive connection with respect to non-axial movement of the upper part 22 is obtained. For instance, the ribs 232 may be dispensed with. The extent of the elevation 23 in radial direction may also vary. For instance, the elevation 23 may also extend to the outer edge of the lower part 21, so that a surface of the lower part 21 opposite the mounting face 20 is completely flat beside the upper part 22.

[0049] In the axial direction the lower part 21 and the upper part 22 are held together via connection means 4 such as screws or bolts (cf. FIG. 2).

[0050] The positive connection 24 counteracts a movement of the upper part 22 with respect to the lower part 21 in the event of a non-axially acting mechanical loading on the upper part 22. Therefore, the mechanical load on the connection means 4 may be significantly reduced. Furthermore, the contact between the lower part 21 and the upper part 22 at the connection plane 25 may be significantly improved. Thus, the positive connection 24 prevents a gap from forming between the flange parts under mechanical loading. This allows the flange to be used for applications requiring a high mechanical robustness, for instance due to large mounting angles with respect to a vertical orientation in space or due to seismic loading.

[0051] For example it has been found by simulations that the short neck of the lower part 21 formed by the elevation 23 significantly increases the mechanical stability of the flange 2 compared to a lower part 21 configured as a flat plate without any elevations at the connection plane.

[0052] The positive connection 24 may be configured as a clearance fit, as a transition fit or as an interference fit. For example, an interference fit is suited as it ensures a strong mechanical coupling between the lower part 21 and the upper part 22 at the mating surfaces of the positive connection 24. For instance, at least one of the flange parts may be subjected to mechanical pressure and/or heating or cooling in order to obtain the interference fit.

[0053] The upper part 22 further comprises an indentation 26 facing an opening 29 of the flange. The indentation 26 is configured to receive an end part of an insulator 3. However, depending on the bushing type an insulator is not necessarily required.

[0054] The lower part 21 further comprises a seat 211 configured to mechanically support a core of the bushing. For example, the seat 211 is a conical portion, where the diameter of the opening 29 tapers in axial direction when seen towards the mounting face 20.

[0055] In the example embodiment shown, the lower part 21 surrounds the upper part 22 to form the positive connection between the flange parts in non-axial direction. However, the arrangement may also be inverted, so that the upper flange part 22 surrounds the lower flange parts 21. This also applies to the subsequent example embodiments.

[0056] An electrical bushing 1 with a flange 2 as described in connection with FIG. 1 is illustrated in FIG. 2. A core 7 is inserted into the opening 29 of the flange 2 and extends into an appliance 9 to which the electrical bushing 1 is mounted at the mounting face 20 of the flange 2. The core 7 is a machined resin impregnated paper condenser core, for example.

[0057] FIG. 2 further illustrates possible positions of recesses 5 configured to receive a gasket such as an O-ring in order to obtain a sealed connection between the lower part 21 and the upper part 22 and/or between the flange 2 and the appliance 9.

[0058] The lower part 21 of the flange 2 further comprises mounting holes 6 configured to match with threaded or through holes provided in the appliance 9 in order to obtain a mechanical connection using mounting means 61, for instance screws.

[0059] Due to the modular configuration of the flange 2 comprising a lower part 21 and an upper part 22, the lower part 21 can be adapted to the electrical appliance 9, for instance with respect to the diameter of the mounting face and/or the position and/or the number of required mounting holes, without the entire flange 2, for example the upper part 22, having to be redesigned. Thus, the customer requirements may be met by machining the casted lower part 21. The upper part 22 and the insulator 3 may be the same for the bushing voltage and current class, independent of the customer interface. This helps to reduce the costs and delivery times.

[0060] A further example embodiment of an electrical bushing 1 is illustrated in FIG. 3. This example embodiment essentially corresponds to that described in connection with FIG. 2. In departure therefrom, the upper part 22 of the flange 2 comprises a circumferential portion 28 that covers at least part of the elevation 23 of the lower part when seen along the axial direction. The circumferential portion 28 may form a roof that helps to prevent moisture or dust from reaching the opening 29 along the interface between the lower part 21 and the upper part 22.

[0061] As illustrated in FIG. 2, a recess 5 may be provided in order to obtain a sealed connection between the elevation 23 of the lower part 21 and the circumferential portion 28 of the upper part.

[0062] In the example embodiments shown in FIGS. 2 and 3 the recesses 5 are provided in the lower flange 21. However, such recesses may be provided alternatively or in addition in the upper flange part 22 and/or in the appliance 9.

[0063] A further example embodiment of a bushing is illustrated in FIG. 4. This example embodiment essentially corresponds to that described in connection with FIG. 2.

[0064] In this example embodiment, the flange 2 is configured to receive a wiper 8. The wiper 8 helps to prevent ingress of contaminants at the interface between the upper flange part 22 and the lower flange part 21. The wiper 28 extends around the upper part 22 and covers a part of the lower part 21 when seen along the axis 10. Of course, such a wiper may also be provided in the previous example embodiments.

[0065] The bushing 1 has been described in connection with a condenser core bushing, but the inventive concept may also be used for any other kind of electrical bushing, such as a solid bushing, also known as a bulk type bushing. The skilled technician is aware that the components of the flange and the bushing may be made from a number of available materials and composites, such that the mention of one specific material must not be understood as a limitation. For instance, the core 7 of the bushing can be made from any suitable material or compound, such as resin impregnated paper, resin impregnated synthetic, resin impregnated nonwoven or solid epoxy.

[0066] The present application claims the priority of EP application 20203662.0, the disclosure content of which is hereby incorporated by reference.

[0067] The invention is not restricted to the example embodiments by the description on the basis of said exemplary embodiments. Rather, the invention encompasses any new feature and also any combination of features, which in particular comprises any combination of features in the patent claims and any combination of features in the example embodiments, even if this feature or this combination itself is not explicitly specified in the patent claims or example embodiments.