High-voltage feedthrough and method for producing same

Abstract

The invention relates to a high-voltage feedthrough (1) having - an internal conductor (2) extending in a longitudinal direction between a first high-voltage terminal and a second high-voltage terminal (2.1, 2.2) of the high-voltage feedthrough (1), and - an insulator body (5) which at least partially encloses the internal conductor (2), characterized in that the insulator body (5) is in the form of a thermoplastic insulator (5.1) which at least partially encloses the internal conductor (2).

Description

[0001] 2024PF00252

[0002] 1

[0003] Description

[0004] High-voltage bushing and method for manufacturing such a bushing

[0005] The invention relates to a high-voltage bushing and a method for manufacturing such a high-voltage bushing.

[0006] In general, the purpose of such a high-voltage bushing is to isolate the inner conductor, which is at a high-voltage potential during operation, from an environment at earth potential, such as the wall of a high-voltage installation. The voltage differences to earth potential can be, for example, more than 300 kV, and in particular more than 600 kV. For this purpose, the inner conductor is typically routed through an insulating body. The conductive control elements embedded in the insulating body serve to control the electric field, thus achieving a uniformity of electrical stress both radially and axially, both inside and outside the insulating body. In this way, critical electrical stresses on the surface and within the insulating body can be avoided or at least reduced.

[0007] Such a high-voltage bushing is known, for example, from WO 2015 / 172806 Al. The insulating layers of the known high-voltage bushing comprise resin-impregnated crepe paper or other wound insulating materials, which include conductive inserts, usually aluminum foil, for capacitive control.

[0008] These high-voltage bushings are manufactured on special lathes. Ovens are required for drying the paper. 2024 PF00252

[0009] 2

[0010] The object of the invention is to provide an improved high-voltage bushing that is as cost-effective and lightweight as possible. Furthermore, it is an object of the invention to provide an improved method for manufacturing such a high-voltage bushing.

[0011] The first problem is solved according to the invention by a high-voltage bushing having the features of claim 1. The second problem is solved according to the invention by a method for manufacturing such a high-voltage bushing having the features of claim 8.

[0012] Advantageous embodiments of the invention are the subject of the dependent claims.

[0013] The high-voltage bushing according to the invention comprises at least one inner conductor which extends in a longitudinal direction between a first and a second high-voltage connection of the high-voltage bushing, and an insulating body which at least partially encloses the inner conductor, wherein the insulating body is designed as a thermoplastic insulation which at least partially encloses the inner conductor.

[0014] By using thermoplastic insulation, complex manufacturing steps such as winding and drying can be eliminated. Potential control via capacitive inserts is also unnecessary. The high-voltage bushing can be manufactured easily. In particular, no furnaces or long lathes are required. Eliminating the furnaces allows for faster manufacturing of the high-voltage bushing. Furthermore, such a high-voltage bushing with thermoplastic insulation is suitable for fully automated production of large quantities without the familiar, time-consuming manual insertion of inserts. The materials used are cost-effective and result in simple manufacturing with significant cost advantages. 2024PF00252

[0015] 3

[0016] For example, thermoplastic insulation can be made from cross-linked polyethylene (also called polyethylene with cross bonds). Using cross-linked polyethylene (also called XLPE or cross-linked polyethylene) eliminates complex manufacturing steps. In particular, production can be automated.

[0017] For example, the thermoplastic insulation can be applied directly to the inner conductor by extrusion and bonded to it. This allows for the use of simple manufacturing equipment, eliminating the need for complex drying ovens. A suitable extrusion machine, similar to those used for high-voltage cable production, is employed for the extrusion process. The inner conductor can optionally be inductively heated during extrusion. For manufacturing connection areas, particularly conical sections, a milling machine, such as a gantry milling machine with a rotary axis and steady rest, can be used instead of a very long lathe.

[0018] Furthermore, the use of cross-linked polyethylene eliminates the need for potential control via capacitive inserts, particularly due to the purity of the cross-linked polyethylene. The field strength at the surface can be reduced by using relatively large conductor diameters. For example, the inner conductor can have a diameter greater than 100 mm. A copper conductor or an aluminum tube is typically used as the inner conductor.

[0019] Alternatively, the thermoplastic insulation can be designed as an extruded profile element, in particular an extruded tube. For example, the extruded profile element can be arranged section by section on the inner conductor. Alternatively, the extruded profile element can be arranged as a continuous tube element on the inner conductor. In particular, the extruded profile element can be arranged on the 2024PF00252

[0020] 4

[0021] The inner conductor is inserted and slid over it to a suitable location or section. Alternatively, the thermoplastic insulation can also be a 3D-printed component, a milled part, or something similar. Optionally, the thermoplastic insulation can be wrapped around the inner conductor section by section or bonded to it section by section.

[0022] A further development provides for a flange, in particular a connection flange and / or mounting flange, which can be arranged on the insulation in a form-fitting and / or material-bonded manner and connected to this insulation. For example, the flange can be mechanically and materially bonded to the thermoplastic insulation by means of adhesive bonding or potting. For example, an epoxy resin, polyester resin, or polyurethane, which can be specifically formulated to be conductive, can be used as the potting material.

[0023] Additionally, a semiconducting or conductive coating (potting compound) can be arranged between the flange and the thermoplastic insulation.

[0024] Viewed axially, the flange can have a fold on one side and a groove on the other. The fold serves in particular for attaching, especially bonding, an external shield, for example a silicone shield or a fiberglass shield (also called GRP tube or fiberglass tube), which are each designed as a single tube.

[0025] The free space within a high-voltage bushing around the inner conductor can be provided with or filled with internal insulation (also called secondary or supplementary insulation). The internal insulation is, for example, an insulating medium such as oil, ester, insulating gas (especially SF6 gas), nitrogen, or air. 2024PF00252

[0026] 5

[0027] Alternatively, the interior can also be filled with a foam material, especially polyurethane foam.

[0028] The high-voltage bushing can have an outer housing that at least partially encloses the insulating body, the housing being at least partially made of a composite material. Internal insulation can be provided between the housing and the insulating body. The internal insulation preferably comprises an insulating gas as the insulating medium. Suitable insulating gases are, for example, SF6 or air under high pressure. The composite material can, for example, be a fiber-reinforced plastic. Preferably, the housing element is made of glass fiber-reinforced plastic, which provides particularly high stability. According to a variant of the invention, the housing element can be a tube made of glass fiber-reinforced plastic (GFRP). Furthermore, external insulation, comprising, for example, annular silicone shields, can be applied to the tubular housing element.In particular, the housing element can be designed as a composite insulator, for example as a GRP tube with vulcanized silicone shields.

[0029] The inventive method for manufacturing the previously described high-voltage bushing comprises at least the following steps:

[0030] - Providing a longitudinally extending inner conductor with a first high-voltage connection and a second high-voltage connection of the high-voltage bushing,

[0031] - Heating the inner conductor and

[0032] - at least partially applying, in particular extruding, an insulating body as a thermoplastic insulation onto the heated inner conductor.

[0033] In particular, a thermoplastic insulation material is pressed as a viscous mass under high pressure and high temperature through a shaping opening of an extrusion device and applied section by section to the 2024PF00252

[0034] The inner conductor is applied. For example, a cross-linked polyethylene material (with cross bonds) is at least partially extruded onto the inner conductor as thermoplastic insulation.

[0035] Alternatively, an extruded profile element, in particular an extruded tube, can be applied, especially by pushing or pulling it onto, at least partially as thermoplastic insulation on the inner conductor. Alternatively, the thermoplastic insulation can be wound, at least partially, onto the inner conductor and / or welded to it.

[0036] Additionally, the thermoplastic insulation in the area of ​​a mounting flange can be provided with a semiconducting or conductive coating.

[0037] 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 drawings show:

[0038] FIG 1 schematically shows a cross-sectional view of a high-voltage bushing,

[0039] FIG 2 schematically shows an enlarged partial view of the high-voltage bushing in the area of ​​a flange and an electrode element, and

[0040] FIG 3 schematically shows an enlarged partial view of the high-voltage feedthrough in the area of ​​the flange.

[0041] Corresponding parts in the figures are labelled with the same reference symbols. For clarity, a coordinate system with Cartesian coordinates x, y, z has been included in each figure. 2024PF00252

[0042] 7

[0043] Figure 1 schematically shows a cross-sectional view of a high-voltage bushing 1.

[0044] The high-voltage bushing 1 is designed as a wall bushing. It serves to pass a high-voltage conductor, which during operation carries a high voltage of, for example, over 500 kV, through a wall. This could, for example, be the wall of a high-voltage direct current transmission system.

[0045] The high-voltage bushing 1 comprises at least one inner conductor 2, which can be connected to a high-voltage conductor (not explicitly shown in Figure 1) at both a first axial end 3 and a second axial end 4 of the high-voltage bushing 1 by means of a first high-voltage connection 2.1 and a second high-voltage connection 2.2. The high-voltage conductor can, for example, be part of an overhead line or a supply line to a transformer winding or to a valve assembly.

[0046] The inner conductor 2 is partially enclosed by an insulating body 5. The insulating body 5 is designed as a thermoplastic insulation 5.1 that directly encloses the inner conductor 2, at least partially.

[0047] The insulating body 5 is shown in more detail in Figure 2.

[0048] For example, the thermoplastic insulation 5.1 can be made from a cross-linked polyethylene material (also called polyethylene with cross-links). The use of cross-linked polyethylene (also called XLPE or cross-linked polyethylene) eliminates complex manufacturing steps. In particular, production can be automated.

[0049] The insulating body 5 is arranged concentrically around a section of the inner conductor 2 (concentricity is defined in 2024PF00252).

[0050] 8

[0051] Generally, this also includes bodies that are arranged almost concentrically due to the manufacturing process.

[0052] The thermoplastic insulation 5.1 is preferably made of a cross-linked polyethylene material. Due to the purity of the cross-linked polyethylene, potential control by capacitive inserts is no longer necessary when using it. In particular, cross-linked polyethylene exhibits high material homogeneity; bubbles, especially air / gas bubbles, are at least reduced or even eliminated. The field strength at the surface can be reduced by using relatively large conductor diameters. For example, the inner conductor 2 can have a diameter greater than 100 mm. A copper conductor or an aluminum tube, for example, is used as the inner conductor 2.

[0053] The thermoplastic insulation 5.1 can be extruded as an insulating layer onto the inner conductor 2, as shown in Figure 1.

[0054] Alternatively, the thermoplastic insulation 5.1 can also be designed as a 3D-printed component, a milled part, or the like. Optionally, the thermoplastic insulation 5.1 can be wrapped around the inner conductor 2 in sections or bonded to it in sections.

[0055] The thermoplastic insulation 5.1, as insulating body 5, forms a compact block that surrounds or covers the inner conductor 2 in a protective and electrically insulating manner. The insulating body 5 is often also referred to as the main insulation.

[0056] The high-voltage bushing 1 further comprises a flange 6, in particular a mounting flange, for fastening the high-voltage bushing 1 to the wall or surface located at earth potential. The flange 6 engages mechanically, in particular by positive locking and / or 2024PF00252

[0057] 9 force-fit, for example by means of a clamping connection, or material-fit, for example by means of a material-fit connection, directly on the insulating body 5.

[0058] The high-voltage bushing 1 can optionally be equipped with a housing 7. The housing 7 can, for example, be made at least partially of a composite material, such as a fiber-reinforced plastic.

[0059] In a space 8 between the housing 7 and the insulating body 5, an internal insulation 9, also called secondary insulation, is arranged, which consists, for example, of an insulating medium, in particular an insulating gas, such as SF6 gas, nitrogen or air.

[0060] An outer layer in the form of screens 13, in particular silicon screens, is attached to the outside of the housing 7.

[0061] The housing 7 and the shields 13 serve to prevent external flashovers along the creepage path of the high-voltage bushing 1. The shields 13 increase the creepage path. The silicone shields 13 are preferably hydrophobic and, in particular, designed to be "self-cleaning" in the rain, thus delaying the formation of conductive layers.

[0062] The housing 7 is not strictly necessary for the immediate electrical and mechanical function of the high-voltage bushing 1. Alternatively, it is possible to omit the housing 7, for example, by using a GRP tube, and to vulcanize the shields 13 directly onto the inner conductor 2 as silicone shielding or to apply a silicone shield over them, analogous to cable terminations in the medium-voltage range.

[0063] At the two axial ends 3, 4 of the high-voltage bushing 1 are two shielding electrodes 10 and 11 for further field shielding. 2024PF00252

[0064] 10

[0065] The high-voltage bushing 1 comprises a first electrode element 12a and a second electrode element 12b. The two electrode elements 12a and 12b are cylindrical and arranged concentrically to the inner conductor 2. Both electrode elements 12a and 12b are mechanically connected to the insulating body 5, as shown in detail in Figure 3.

[0066] Each of the electrode elements 12a or 12b extends axially out of the insulating body 5. The first electrode element 12a extends out of the insulating body 5 towards the first axial end 3, and the second electrode element 12b extends out of the insulating body 5 towards the second axial end 4.

[0067] In particular, each of the two electrode elements 12a and 12b extends axially beyond the, for example, conical or cylindrically tapered ends 5a and 5b of the insulating body 5. The insulating body 5 forms a mechanical support for the electrode elements 12a, 12b.

[0068] Each of the two electrode elements 12a and 12b may optionally have a rounding 14a and 14b at one of their ends, which serve to avoid field strength increases.

[0069] Additionally, a mounting plate 18 for fastening the high-voltage feedthrough 1 can optionally be provided and held in the area of ​​the flange 6, in particular at one end of the flange 6.

[0070] Figure 2 schematically shows an enlarged partial view of the high-voltage feedthrough 1 in the area of ​​the flange 6 and one of the electrode elements 12b leading out of the insulating body 5.

[0071] The end 5b pointing towards the electrode element 12b can be conical or cylindrical, as shown by the dashed lines. 2024PF00252

[0072] 11

[0073] The electrode element 12b and the inner conductor 2 arranged therein protrude from the insulating body 5 at end 5b. Similarly, the electrode element 12a and the inner conductor 2 protrude from the insulating body 5 at end 5a, as shown in Figure 1.

[0074] As an alternative to the extruded layer, the thermoplastic insulation 5.1 can be designed as an extruded profile element 5.2, in particular an extruded tube. For example, the extruded profile element can be arranged section by section on the inner conductor 2. In particular, the extruded profile element 5.2 can be placed on the inner conductor 2 and slid over this inner conductor 2 to a corresponding location or section of the inner conductor 2. The extruded profile element 5.2 can also be designed as a tube that extends along the inner conductor 2, in particular largely completely along the inner conductor 2, and surrounds it.

[0075] The flange 6 is, for example, a connection flange and / or a mounting flange that is arranged on the insulating body 5 in a form-fitting and / or material-bonded manner and connected to this insulating body 5. For example, the flange 6 can be mechanically and materially bonded to the thermoplastic insulation 5.1 by means of adhesive bonding. In the example according to Figure 2, a potting material 15, for example an epoxy resin, which is particularly conductive, is introduced between the flange 6 and the thermoplastic insulation 5.1 and materially bonded to the flange 6 on the one hand and to the insulating body 5 on the other.

[0076] The potting material 15 (also called potting compound) is specifically designed as a semiconducting or a conductive layer 15.1. 2024PF00252

[0077] 12

[0078] The housing 7 with the screens 13 is flush with the flange 6.

[0079] Figure 3 schematically shows an enlarged partial view of the high-voltage bushing 1 in the area of ​​the flange 6.

[0080] The flange 6 can have, viewed axially, a fold 6.1 on one side and a groove 6.2 on the other. The fold 6.1 serves in particular for arranging, especially bonding, an external shield, for example, of the housing 7 with a shield 13 designed as a silicone shield. Instead of silicone shields, a fiberglass shield (also called GRP tube or fiberglass tube), which is designed, for example, as a tube, can also be arranged on the outside of the housing 7.

[0081] The groove 6.2 can be provided on both sides in the axial direction. The groove 6.2 serves in particular to receive a seal 16, especially a sealing ring, for sealing and / or a clamping element 17 for coaxially clamping the components, such as the insulating body 5 and the inner conductor 2, which are arranged coaxially to each other. The seal 16 itself can be designed as a clamping element 17. Alternatively, these can be designed as separate elements. The seal 16 can be arranged and held in the area of ​​the flange 6 only temporarily, for example, only for sealing during filling with the potting material 15, for example, with epoxy resin, and during the curing of the potting material 15. The seal 16 can be removed again after the potting material 15 has cured. Alternatively, it can remain in place.

[0082] The potting compound 15 can be introduced into a device for coaxial alignment and, if necessary, evacuation of air from the high-voltage bushing 1 via a bore in the area of ​​the flange 6 after the pre-assembled high-voltage bushing 1 has been erected. 2024PF00252

[0083] 13

[0084] When using two seals 16, the potting can be carried out lying in the area of ​​the flange 6, for example by introducing the potting material 15 through a lower bore and evacuation / vacuum through an upper bore.

[0085] To produce the previously described high-voltage bushing 1, the longitudinally extending inner conductor 2 with its first high-voltage connection 2.1 (shown in Figure 2) and its second high-voltage connection 2.2 (shown in Figure 2) is first provided and heated, in particular preheated.

[0086] Subsequently, at least a portion of a thermoplastic insulation 5.1 is applied to the heated inner conductor 2, in particular by extrusion, to form the insulating body 5. During the extrusion process of the insulation 5.1, the inner conductor 2 can be heated inductively. As thermoplastic insulation 5.1, a cross-linked polyethylene material is extruded at least partially onto the inner conductor 2. Alternatively, as thermoplastic insulation 5.1, an extruded profile element 5.2 can be applied at least partially to the heated inner conductor 2, in particular by snapping and / or sliding it on.

[0087] Alternatively, the thermoplastic insulation 5.1 can be at least partially wound onto the heated inner conductor 2 and / or welded to it.

[0088] Subsequently, the thermoplastic insulation 5.1 in the area of ​​the flange 6 to be attached, and if necessary beyond, can be provided with the potting material 15 as a semiconducting or conductive layer 15.1. This serves for field control. In other words, for field control, a coating with appropriate conductivity can be applied (partially) to the insulating body 5 as layer 15.1. 2024PF00252

[0089] 14

[0090] The potting material 15 can, for example, be introduced into a device for coaxial alignment and, if necessary, evacuation of the air from the high voltage feedthrough 1 via a bore in the area of ​​the flange 6 after the pre-assembled high voltage feedthrough 1 has been erected.

[0091] When using two seals 16, the potting can be carried out lying in the area of ​​the flange 6, for example by introducing the potting material 15 through a lower bore and evacuation / vacuum through an upper bore.

[0092] After the thermoplastic insulation 5.1 and the semiconducting or conductive layer 15.1 have hardened and cooled, the flange 6 can be mechanically fastened with the semiconducting or conductive potting compound 15.

[0093] Alternatively, the connection between the flange 6 and the insulating body 5 can be made mechanically, for example with a clamping set that can be integrated into the flange component or screwed to it.

[0094] After the flange 6 has been attached, the housing 7 is then mounted and fastened with the shields 13 designed as silicone shields and / or the seals 16 and / or clamping elements 17.

[0095] Although the invention has been further illustrated and described in detail by means of 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

2024PF00252 15 Patent claims 1. High-voltage bushing (1) with - an inner conductor (2) which extends in a longitudinal direction between a first and a second high-voltage connection (2.1, 2.2) of the high-voltage bushing (1), and - an insulating body (5) which at least partially encloses the inner conductor (2), characterized in that the insulating body (5) is designed as a thermoplastic insulation (5.1) which at least partially encloses the inner conductor (2).

2. High-voltage bushing (1) according to claim 1, characterized in that the thermoplastic insulation (5.1) is formed from a cross-linked polyethylene material.

3. High-voltage bushing (1) according to claim 1 or 2, characterized in that the thermoplastic insulation (5.1) is applied to the inner conductor (2) by extrusion and connected to it.

4. High-voltage feedthrough (1) according to claim 1 or 2, characterized in that the thermoplastic insulation (5.1) is designed as an extruded profile element (5.2).

5. High-voltage bushing (1) according to one of the preceding claims, characterized in that a flange (6) is arranged and connected on the thermoplastic insulation (5.1) in a form-fitting and / or material-fitting manner.

6. High-voltage bushing (1) according to claim 5, characterized in that between flange (6) and 2024PF00252 16 thermoplastic insulation (5.1) a semiconducting or conductive layer (15.1) is arranged.

7. High-voltage feedthrough (1) according to claim 5 or 6, characterized in that the flange (6) has at least one fold (6.1) on one side and at least one groove (6.2) on the other side, viewed in the axial direction.

8. Method for manufacturing a high-voltage bushing (1) according to one of the preceding claims, characterized by the following steps: - Providing a longitudinally extending inner conductor (2) with a first high-voltage connection (2.1) at one axial end (3) and a second high-voltage connection (2.1) at another axial end (4) of the high-voltage bushing ( 1 ), - Heating the inner conductor (2) and - at least partially applying an insulating body (5) as a thermoplastic insulation (5.1) to the heated inner conductor (2) .

9. Method according to claim 8, characterized in that a cross-linked polyethylene material is extruded at least partially onto the inner conductor (2) as thermoplastic insulation (5.1).

10. Method according to claim 8, characterized in that an extruded profile element (5.2) is applied at least partially to the inner conductor (2) as thermoplastic insulation (5.1).

11. Method according to claim 8, characterized in that the thermoplastic insulation (5.1) is applied at least partially to the 2024PF00252 17 inner conductor (2) is wound and / or welded to it.

12. Method according to one of claims 8 to 11, characterized in that the thermoplastic Insulation (5.1) in the area of ​​a flange (6) is provided with a semiconducting or conductive layer (15.1).

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