High-voltage insulator comprising an insulator cap

Abstract

The invention relates to a high-voltage insulator comprising a support insulator and an insulator cap, wherein the insulator cap has a cap wall and a cap cover which form a cavity for receiving an end portion of the support insulator. The insulator cap is designed as a fastening element in order to connect the support insulator to an electrical component by means of one or more connecting elements, and the insulator cap has a plurality of fins arranged on an outer surface of the cap wall.

Description

TRG 252 HIGH-VOLTAGE INSULATOR WITH INSULATOR CAP Field of invention

[0001] The present invention lies in the technical field of high-voltage insulators, in particular support insulators with insulator caps, which are provided for fastening the insulators to electrical, magnetic field-generating components. background

[0002] Electrical components that generate magnetic fields, such as air-core inductors, must be electrically insulated from ground and mechanically stable to ensure their resistance to short-circuit forces, wind, and earthquakes. For this purpose, the components are typically placed on support insulators, which usually have a metal insulator cap at their upper end. The component is mechanically connected to this cap, for example, by screw connections. If an insulator is placed in a strong, time-varying magnetic field, as is the case, for example, in the vicinity of dry-insulated air-core inductors, eddy currents are induced in the metal insulator cap of the high-voltage insulator. This leads to heating of the insulator cap that exceeds permissible values ​​and can result in damage or failure.which can lead to a mechanical failure of the cementation or bonding of the insulator cap between the porcelain or composite component.

[0003] In particular, the problem of unacceptably high heating of the insulator caps occurs when they are positioned too close to the magnetic field-generating electrical components or parts, such as the coil windings of an air-core inductor. TRG 252

[0004] According to current technology, the problem has been solved by increasing the distance between the insulator cap and the electrical component. This was achieved using insulator mountings with additional height, so-called extension elements or extension supports, which were positioned between the insulator cap and the electrical component. However, these extension elements have significant drawbacks: they not only increase material and manufacturing costs, but also necessitate a comprehensive revision of the mechanical calculations to ensure the stability of the entire device against the aforementioned mechanical loads. Furthermore, the more complex design resulting from the additional number of components complicates mechanical verification, whether through calculations or simulations, which considerably increases the development effort.

[0005] The aim of the present invention is therefore to provide a high-voltage insulator which, when used on electrical components that generate a strong and time-varying magnetic field, ensures high mechanical stability. Summary

[0006] One embodiment relates to a high-voltage insulator comprising a support insulator and an insulator cap, wherein the insulator cap has a cap wall and a cap lid forming a cavity for receiving an end piece of the support insulator. The insulator cap is configured as a fastening element to connect the support insulator to an electrical component via one or more connecting elements, and the insulator cap has a plurality of fins arranged on an outer surface of the cap wall.

[0007] Such a high-voltage insulator has the advantage that it can be installed at a short distance from a magnetic field-generating electrical component, such as the coil winding of an air-core inductor, without risking critical heating of the insulator cap. The fins on the outside of the cap wall increase the surface area of ​​the insulator cap and enable a TRG 252 Efficient heat dissipation to the surrounding air. This prevents negative thermal and, consequently, mechanical effects on the connection between the insulator component and the cap, and also reduces the need for additional extension elements to the electrical component. This ensures the long-term mechanical integrity of the structure.

[0008] In one embodiment, the cap lid can have a substantially flat top surface.

[0009] This has the advantage of even force distribution and thus an improvement in the mechanical stability of the connection between the cap and the electrical component. Furthermore, a flat top surface facilitates the assembly and fastening of connectors or other components, which simplifies the manufacturing and maintenance of the device and increases its robustness.

[0010] In one embodiment, an outer edge of the cap lid can be raised on its upper side.

[0011] This has the advantage of simplifying assembly for attaching fasteners such as screws. Furthermore, it reduces eddy currents in the insulator cap, as the area directly exposed to the magnetic field is reduced.

[0012] In one embodiment, the raised outer edge can be interrupted at one or more points.

[0013] This has the advantage of a further reduction of eddy currents in the insulator cap, as the area directly exposed to the magnetic field is further reduced.

[0014] In one embodiment, the cap cover can have one or more blind holes for attaching one or more connecting elements. This offers the advantage of simplified assembly.

[0015] In one embodiment, the cap wall can essentially have a cylindrical shape. This has the advantage that the insulator cap is particularly TRG 252 It can be easily placed on the end piece of the support insulator and connected to it.

[0016] In one embodiment, the majority of fins can be arranged radially. This has the advantage of ensuring uniform heat dissipation.

[0017] In one embodiment, the majority of fins can be arranged parallel to each other.

[0018] In one embodiment, the majority of fins can have a tapered shape starting from the outside of the cap wall.

[0019] This has the advantage that the wider base on the cap wall ensures stable attachment and effective heat transfer from the cap to the fins. The tapering towards the tip or end face optimizes airflow around the fins, improves convection, and increases heat dissipation efficiency. At the same time, the narrower tip reduces material consumption and weight, minimizing both costs and mechanical stress. Additionally, this design allows the insulator cap to be manufactured particularly well and easily using a casting process.

[0020] In one embodiment, the outside of the cap wall can have a sheath which is detachably connected to the outside of the cap wall and wherein the sheath has a plurality of fins.

[0021] This has the advantage that existing insulator caps can be adapted particularly easily.

[0022] In one embodiment, a thermal paste can be applied between the outer surface of the cap wall and the casing. This has the advantage of resulting in particularly good heat dissipation.

[0023] In one embodiment, the insulator cap can be positively connected to the end piece of the support insulator. This has the advantage of simple assembly while simultaneously increasing stability. TRG 252

[0024] In one embodiment, the insulator cap for connection to the supporting insulator can be filled with cement-based filler or polymer material. This has the advantage of a secure, weather-resistant, and therefore durable construction.

[0025] In one embodiment, the insulator cap and / or the casing can contain a non-magnetic metal alloy. This has the advantage of reducing eddy currents in the insulator cap, which improves thermal stability. As a result, the cap can be positioned even closer to the electrical component without compromising its mechanical stability.

[0026] Another embodiment relates to a high-voltage device comprising an electrical component for generating a time-varying magnetic field, one or more connecting elements, and one or more high-voltage insulators. The insulator cap of the respective high-voltage insulator is connected to the electrical component via the one or more connecting elements, and eddy currents are induced in the insulator cap as a result of the magnetic field.

[0027] In one embodiment, the electrical component can be an air-core inductor.

[0028] In one embodiment, the one or more connecting elements can comprise a winding fastening element of a retaining star, which is arranged at an axial end of the air choke coil and at least one support fastening for fastening the insulator cap to the winding fastening element.

[0029] In one embodiment, the one or more connecting elements can be retaining elements embedded in or attached to the winding, arranged at an axial end of the air-core choke coil, and comprising at least one support fastening for attaching the insulator cap to the winding fastening element. TRG 252 Brief description of the characters

[0030] Exemplary embodiments of the present invention are described below with reference to the accompanying figures:

[0031] Fig. 1 is a perspective view of a state-of-the-art air-core inductor, which is supported by four high-voltage insulators.

[0032] Fig. 2 is a perspective view of a prior art insulator cap with an extension element attached to it. The extension element is mounted on one of the winding mounting elements of the support star of the air-core choke coil.

[0033] Fig. 3 is a perspective view of a prior art air-core choke coil in which an additional third corona ring is attached to the underside next to the extension elements.

[0034] Fig. 4 is a perspective view of a high-voltage insulator according to the invention.

[0035] Fig. 5 is a perspective view of an insulator cap according to the invention with radially arranged fins.

[0036] Fig. 6 is a perspective view of an insulator cap according to the invention with parallel fins.

[0037] Fig. 7 is a perspective view of a high-voltage device according to the invention, comprising an electrical, magnetic field-generating component in the form of an air-core inductor, which is supported by three high-voltage insulators according to the invention.

[0038] Fig. 8 is a perspective view of an air-core choke coil, with a flat connecting element TRG 252 attached to several winding mounting elements. The connecting elements are suitable for each receiving a high-voltage insulator according to the invention. Detailed description

[0039] Fig. 1 shows a perspective view of a prior art air-core inductor 100. The air-core inductor 100 is an electrical component used in high-voltage applications to limit or filter alternating currents. The air-core inductor 100 has a cylindrical housing 101, which is held at both axial ends 102, 103 by a support star (only the upper support star 104 is visible here). Each support star 104 has several star-shaped winding fastening elements 105. The air-core inductor 100 is supported by high-voltage insulators 106. In this illustration, four insulators 106 are shown by way of example, but there can also be three or more than four. The insulators 106 serve for mechanical stabilization and electrical insulation.The high-voltage insulators 106 are support insulators that ensure a secure connection between the air choke coil 100 and the ground fixings 107, so that the air choke coil is stable and insulated from earth with the help of the support insulators.

[0040] In high-voltage applications, an air-core inductor 100 generates a strong, time-varying magnetic field in its windings due to the current flow, which can range from 10 to several thousand amps at mains frequency. The resulting stray magnetic fields induce eddy currents in nearby metallic components, which can lead to undesirably high temperatures. The insulators 106, and in particular their insulator caps 108, are directly exposed to this stray magnetic field.

[0041] The insulator caps 108 are located at the lower axial end 103 of the air-core inductor 100, very close to the lower edge of the cylindrical housing 101. The upper central area of ​​each insulator cap 108 can be exposed to a peak magnetic field of, for example, approximately 25 to 150 mT. Due to induced eddy currents, local heating of over 100 K can occur in the insulator caps 108. Such high temperatures can be sustained (TRG 252). This puts thermal stress on the material, and in particular on the connection between the insulator component and the insulator caps 108, and impairs or destroys its mechanical properties. This can lead to deformation, weakening, or failure of the structure, which no longer guarantees mechanical stability.

[0042] According to one embodiment, the air-core inductor 100 has corona rings 109 at its two axial ends 102, 103. These ensure that the electric field lines are distributed more evenly over the surface. This avoids areas of high field strength, especially at sharp edges or corners.

[0043] Fig. 2 shows a perspective view of an insulator cap 200 at the upper end of a support insulator (not fully shown) according to the prior art with an extension element or extension support 201 attached to it on a winding fastening element 202 of a lower winding fastening element of an air choke coil (not fully shown).

[0044] The extension element 201 is an insulator mounting with additional height, which is arranged between the insulator cap 200 and the star arm 202.

[0045] The extension element 201 serves to increase the distance to the magnetic field-generating component, the air-core inductor. The extension element 201 and the mounting element 202 together result in a total height 203, which is defined as the distance between the lower end of the air-core inductor and the top of the cap of the insulator cap 200. In high-voltage applications of this type, this distance is typically between 50 mm and more than 300 mm to ensure the stability and safe operation of the high-voltage insulator. The large distance reduces the magnetic field strength at the insulator cap 200, lowers the induced eddy currents, and thus minimizes heat generation in the insulator cap 200. However, this solution has significant disadvantages. It not only increases the material and manufacturing costs as well as the overall height of the high-voltage device, but also complicates mechanical verification (TRG 252). through more complex calculations and simulations. The design becomes significantly more demanding due to the additional components, and further material costs arise not only from the extension element itself and the associated additional fastening points, such as screw connections between the extension element and the winding fastening element, but also from the need for an additional, third corona ring 204 with additional supports (not shown) at the level of the insulator cap 200 to control the electric field there as well. This increases both the costs and the maintenance effort, while the overall efficiency of the high-voltage device decreases.

[0046] Fig. 3 shows a perspective view of a prior art air-core inductor 300, in which an additional third corona ring 303 is attached to the lower axial end 301 in addition to the extension elements 302. As can be seen, the extension elements result in a significantly more complex structure, involving increased material usage and a considerable increase in overall height.

[0047] Fig. 4 shows a perspective view of an embodiment of a high-voltage insulator 400 according to the invention, which is designed for use in high-voltage applications.

[0048] The high-voltage insulator 400 comprises a support insulator 401 and an insulator cap 402 attached to one end of the support insulator 401. The insulator cap 402 has a plurality of fins 403 to improve heat dissipation. The insulator cap 402 is connected to the end of the support insulator 401 by cementing or bonding. The support insulator 401 can be made of porcelain or composite materials. The fins 403, also called flags, are attached to the outside of the insulator cap 402. The high-voltage insulator 400 is connected via a flat connecting element 404, e.g., a flange, to an electrical component that generates a time-varying magnetic field.The insulator cap 402 is made of metal for secure and detachable attachment to the electrical component, for example using screw connections, so that this stray magnetic field acts on the insulator cap 402 and generates eddy currents within it. (See TRG 252.) The fin arrangement 403 increases the thermal resistance of the insulator cap 402. This allows the insulator cap 402 to be mounted closer to the electrical component. Optionally, the insulator cap 402 can contain a non-magnetic metal alloy, which further increases its resistance to stray magnetic fields. The insulator cap 402 is then, for example, a component forged from a non-magnetic metal alloy or manufactured as a welded construction. This has the advantage of reducing eddy currents in the insulator cap, which improves thermal stability. The cap can thus be mounted even closer to the electrical component without compromising its mechanical stability. A further advantage is the simple and economical manufacturing process, even in small batches.

[0049] The insulator cap 402 is preferably securely connected to the end piece of the support insulator by a form-fitting connection. For this purpose, the insulator cap 402 is optionally filled with cement-based fillers or polymer material. The polymer material is preferably a synthetic resin. This has the advantage of a secure, weather-resistant, and therefore durable structure, especially when using an insulator component made of composite material.

[0050] On the opposite side of the support insulator 401 is a base fixing 405, which ensures secure anchoring of the high-voltage device. Alternatively, another support insulator or another electrical component can be located at this point.

[0051] According to one embodiment, the electrical component is an air-core inductor, for example, a dry-insulated air-core inductor. In this embodiment, the insulator cap 402 is additionally fastened to an axial end of the air-core inductor via a further connecting element 406, the winding fastening element. The connecting element 404 is a support fastening, e.g., a flange, and the connecting element 406, e.g., a winding fastening element, together result in an overall height that is defined as the distance between the lower end of the air-core inductor and the top of the cap cover of the insulator cap 402. Preferably, the overall height is less than 10 cm. Particularly preferably, the overall height is less than 5TRG 252. cm. Thanks to the design according to the invention, thermal stability and optimal mechanical stability are still ensured despite the low height.

[0052] There may also be other connecting elements, e.g. retaining elements embedded in or attached to the winding, which are arranged at an axial end of the air choke coil.

[0053] Fig. 5 shows a perspective view of an insulator cap 500 according to the invention, which is part of the high-voltage insulator 400 of Fig. 4.

[0054] The insulator cap 500 has a substantially cylindrical shape and comprises a cap wall 501 (or cap shell) and a cap cover 502. The cap wall 501 and the cap cover 502 together form a cavity for receiving an end piece of the support insulator. The insulator cap 500 includes a longitudinal axis 503 that runs along the cylindrical axis of symmetry of the insulator cap 500 and connects the central point of the cap cover 502 with the center of the cavity.

[0055] The cap cover 502 has a substantially flat top surface, with an outer rim 504 of the cap cover 502 raised on its top surface. This outer rim contains one or more blind holes 505, which serve to receive fasteners, such as screws. These enable the secure attachment of connecting elements to the cap cover 502, such as the connecting element 404 from Fig. 4.

[0056] The outer edge 504 has one or more breaks 506. These reduce the area directly exposed to the magnetic field and thereby reduce the eddy currents in the insulator cap 500.

[0057] In one embodiment, if the insulator cap 500 is designed to connect the support insulator to an air-core choke coil, the outer edge 504 has at least one pair of symmetrically arranged breaks 506, which serve for the positive locking of a winding fastening element. This further increases the mechanical stability and prevents horizontal slippage. TRG 252

[0058] According to one embodiment, a plurality of fins 507 are arranged on the outside of the cap wall 501 of Fig. 5.

[0059] According to one embodiment, the fins 507 are radially oriented and evenly distributed on the outside of the cap wall 501 around the longitudinal axis 503 of the insulator cap 500. Each fin is essentially vertically oriented, meaning that the longitudinal axis 508 of the fin runs parallel to the longitudinal axis 503 of the insulator cap 500. Such a fin arrangement ensures uniform and symmetrical heat dissipation.

[0060] In an alternative embodiment, the fins 507 are inclined at an angle to the longitudinal axis 503 of the insulator cap 500. This means that the longitudinal axis 508 of the fins is not parallel to the longitudinal axis 503, but is oriented at a specific angle to it. The inclined arrangement of the fins directs the air along a spiral or diagonal path, thereby increasing the flow efficiency around the insulator cap. This results in improved convection and allows for faster heat dissipation.

[0061] Fig. 6 is a perspective view of an insulator cap 600 according to a further embodiment according to the invention.

[0062] The insulator cap 600 is essentially the same as the insulator cap 500 shown in Fig. 5, except for the arrangement of the fins 607. While these are radially oriented in the insulator cap 500, they run parallel or nearly parallel to each other in the insulator cap 600. This means that the vertical axes 602 of the fins 607, which extend from the cap wall 601 towards the tip or end face of the fin, are essentially parallel. This design allows for further optimization of the fins' exposure to the coil's magnetic field (a vector quantity) and a reduction in overall losses. The operating limits are thereby extended to higher magnetic field values.

[0063] Regardless of a specific fin orientation, as described in Fig. 5 or Fig. 6, according to one embodiment the density of the fins TRG 252 507, 607 in certain areas of the cap wall 501, 601 increased, for example in regions with increased heat stress.

[0064] Optionally, according to a further embodiment, the fins 507, 607 can also have a tapered shape starting from the outside of the cap wall 501, 601, in the direction of the tip or end surface of the fin. Each fin is preferably designed as a trapezoidal prism, particularly preferably as an isosceles trapezoidal prism, with the base and top surfaces being designed as isosceles trapezoids. The tapering thus occurs along the lateral axis in the direction of the vertical axis of the fin. Additionally, a tapering along the longitudinal axis 508 in the direction of the vertical axis of the fin can also occur.

[0065] In an alternative embodiment, the fins 507, 607 are not attached directly to the outside of the cap wall 501, 601 or formed integrally with the insulator cap 500, 600, but are arranged on a separate casing. This casing is detachably attached to the outside of the cap wall 501, 601. Optionally, a thermally conductive paste is applied between the casing and the outside of the cap wall 501, 601. Optionally, the casing with fins can be made of a non-magnetic metal alloy. In one embodiment, the insulator cap and / or the casing can be forged from a non-magnetic metal alloy or manufactured as a welded construction. This has the advantage of reducing eddy currents in the insulator cap, which improves thermal stability. The cap can thus be positioned even closer to the electrical component without compromising its mechanical stability.Another advantage results from the simple and economical production with small quantities.

[0066] Fig. 7 shows a perspective view of a high-voltage device 700 according to the invention, which comprises an electric, magnetic field-generating component in the form of an air-core choke coil 701, which is supported by high-voltage insulators 702 according to the invention.

[0067] Three high-voltage insulators 702 are shown as examples (the rear one in the middle is partially obscured by the air-core choke). The TRG 252 However, according to further embodiments, the high-voltage device 700 can also have more than three high-voltage insulators 702.

[0068] The high-voltage insulators 702 comprise an insulator cap 703, wherein the insulator cap 703 is an insulator cap as described in Fig. 4 to Fig. 6.

[0069] Fig. 8 shows a perspective view of an air choke coil 800 according to a further embodiment, wherein a retaining star 802 with several star-shaped winding fastening elements 803 is arranged at the lower axial end 801 of the air choke coil 800.

[0070] A flat connecting element 804 is attached to several selected winding fastening elements 803, which is provided for mounting a high-voltage insulator according to the invention, as described in connection with Fig. 4 to Fig. 6.

[0071] A comparison of Fig. 3 and Fig. 8 illustrates that the use of the high-voltage insulators according to the invention allows for material savings. The high-voltage insulator enables the use of flat connecting elements 404, as described in Fig. 4. In particular, a third corona ring, as would be required in conventional designs, is not necessary. Instead, the insulator cap of the high-voltage insulator is located at the same level as the second corona ring 805. This ensures continued thermal and mechanical stability.

Claims

TRG 252 Patent claims 1. High-voltage insulator comprising a support insulator and an insulator cap, wherein the insulator cap has a cap wall and a cap lid forming a cavity for receiving an end piece of the support insulator, and wherein the insulator cap is configured as a fastening element to connect the support insulator to an electrical component via one or more connecting elements, and wherein the insulator cap has a plurality of fins arranged on an outside of the cap wall.

2. High-voltage insulator according to claim 1, wherein the cap cover has a substantially flat top surface.

3. High-voltage insulator according to claim 1 or 2, wherein an outer edge of the cap cover is raised on its upper surface.

4. High-voltage insulator according to claim 3, wherein the raised outer edge is interrupted at one or more points.

5. High-voltage insulator according to one of the preceding claims, wherein the cap cover has one or more blind holes for fastening the one or more connecting elements.

6. High-voltage insulator according to one of the preceding claims, wherein the cap wall has a substantially cylindrical shape.

7. High-voltage insulator according to claim 6, wherein the majority of fins are arranged radially.

8. High-voltage insulator according to claim 6, wherein the majority of fins are arranged parallel to each other. TRG 252 9. High-voltage insulator according to one of the preceding claims, wherein the majority of fins have a tapered shape extending from the outside of the cap wall.

10. High-voltage insulator according to one of the preceding claims, wherein the outside of the cap wall has a sheath which is detachably connected to the outside of the cap wall and wherein the sheath has a plurality of fins, and wherein a thermal paste is optionally applied between the outside of the cap wall and the sheath.

11. High-voltage insulator according to one of the preceding claims, wherein the insulator cap is positively connected to the end piece of the support insulator, and wherein the insulator cap is optionally filled with cement-based fillers or polymer material for connection to the support insulator.

12. High-voltage insulator according to any of the preceding claims, wherein the insulator cap and / or the casing comprises a non-magnetic metal alloy.

13. High-voltage device, comprising: an electrical component for generating a time-varying magnetic field; one or more connecting elements; and one or more high-voltage insulators according to one of claims 1 to 12, wherein the insulator cap of the respective high-voltage insulator is connected to the electrical component via one or more connecting elements and eddy currents are induced in the insulator cap as a result of the magnetic field.

14. High-voltage device according to claim 13, wherein the electrical component is an air-core inductor.

15. High-voltage device according to claim 14, wherein the one or more connecting elements are a winding fastening element that is attached to an axial end TRG 252 is arranged in the air choke coil and includes at least one support fastening for fastening the insulator cap to the winding fastening element.

16. High-voltage device according to claim 15, wherein the retaining elements are embedded in or attached to the winding and are arranged at an axial end of the air choke coil and comprise at least one support fastening for fastening the insulator cap to the winding fastening element.

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