Insulator for high-voltage applications

Abstract

Insulator (1) for high-voltage applications comprising - an essentially rotationally symmetrical hollow tube (2) made of glass fiber reinforced epoxy resin, - a shield (3) made of silicone attached around the circumference of the hollow tube (2), - a foot flange (4) at a lower end (5) of the hollow tube (2), - a holder (6) for a device for high-voltage applications at an upper end (7) of the hollow tube (2), wherein - the insulator (1) has a closing element (8), a plug, which is arranged inside the hollow tube (2) and closes the end face of the upper end (7) of the hollow tube (2) and seals to the outside, wherein - the bracket (6) has a rotationally symmetrical connection area (9), - the insulator (1) at the upper end (7) of the hollow tube (2) has a radially circumferential joining area (10) which is free of silicone shielding (3), - wherein the holder (6) can be connected to the insulator (1) in such a way that the connection area (9) of the holder (6) positively surrounds the joining area (10) of the insulator (1), wherein - the closure element (8), the hollow tube (2) and the holder (6) each have at least one transverse bore (11) which are aligned coaxially with each other, - into which at least one transverse bore (11) a locking bolt (12) can be inserted and fixed.

Description

[0001] The invention relates to an insulator for high-voltage applications, in particular a post insulator, such as is used for supporting busbars, conductor cables, choke coils or other equipment in high-voltage technology.

[0002] The equipment mentioned operates at a specific potential and must therefore be insulated from earth and / or other potentials at a certain distance.

[0003] For many decades, single-piece or multi-piece post insulators, i.e. those consisting of several individual insulators and assembled together, have been used to support and insulate busbars, conductor cables or choke coils against earth.

[0004] Document CN 210516349 U describes a hollow column insulator comprising a hollow insulating tube and a shield arranged around the outer circumference of the insulating tube. A flange is arranged at both ends of the insulating tube, the flange comprising an upper flange and a lower flange. An end sealing structure is provided inside the insulating tube at both ends. Furthermore, the hollow column insulator is provided with an automatic closing device, the automatic closing device comprising a closing element and a self-compression spring. The closing element is locked to the surface of the end sealing structure and closes the second through hole with the self-compression spring.

[0005] An insulator for a pantograph of a rail vehicle is known from published patent application DE 102010016384 A1. The insulator has an upper head section and a lower foot section. The foot section and the head section are connected to each other by a support member designed as a hollow profile. An insulator jacket is arranged in the area between the foot section and the head section, which has a head section and a foot section. Shields are arranged between the head and foot sections to increase the electrical creepage distance.

[0006] Document DE 622269 A describes a method for sealing a cavity insulator. A solid insulating compound is introduced into the cavity of the insulator and, after the ceiling plate is attached, melted by heating. After melting on the plate, the insulating compound solidifies again as a layer upon cooling.

[0007] Document US 2008 / 0083555 A1 describes an insulator for electrical power lines with an end clamp. The insulator has an end clamp attached to the upper end of an insulator housing with a bolt and nut. The insulator housing comprises a rod covered with insulating rubber. For attaching the insulator to a power pole, the insulator has a base connection piece with a screw hole at its lower end. An upper fastening piece is connected to the rod of the insulator housing. A mounting cylinder protrudes integrally from the upper part of the upper fastening piece to connect to a clamp base of the damper.

[0008] WO 2018 / 191159 A1 discloses an air-core choke for use in an electrical power transmission and distribution network. The choke is mounted on an electrically insulated support structure and insulated from ground. The support structure comprises several post insulators, each of which has a mounting bracket at its upper end that is directly connected to the coil. To attach the mounting bracket to the post insulator, the post insulator has a mounting flange that is screwed and bonded to a flange of the post insulator.

[0009] The entire system is exposed to high forces, particularly bending, torsional, tensile, and compressive forces, due to the high currents and voltages and the resulting magnetic fields, as well as environmental influences such as local weather conditions. The flange connection between the coil or its mounting devices and the support insulators represents a weak point and thus a potential source of failure.

[0010] Furthermore, installing the mounting brackets on the flanges of the post insulators on site is complex, as each mounting bracket must be correctly positioned and then firmly secured with several screws. Any angular misalignments that may occur must also be corrected.

[0011] It is an object of the present invention to provide an improved concept for connecting a support insulator to a holder for high-voltage equipment, which, in addition to high strength, also enables simple assembly of the device on site.

[0012] This object is achieved by the subject matter of the independent claim. Further embodiments are the subject matter of the dependent claims.

[0013] Accordingly, an insulator for high-voltage applications is provided, in particular a post insulator comprising a substantially rotationally symmetrical hollow tube made of glass-fiber-reinforced epoxy resin, a silicone shielding attached circumferentially to the hollow tube, and a base flange arranged at a lower end relative to a longitudinal axis A of the hollow tube. At an upper end relative to the longitudinal axis A of the hollow tube, the insulator has a holder for an operating device for high-voltage applications. Such operating devices can be, for example, a choke coil supported on several insulators by means of a gear ring, or a busbar held at a distance from the ground by the insulator.

[0014] Furthermore, the insulator has a closure element arranged within the hollow tube, which closes the front side of the upper end relative to the longitudinal axis A of the hollow tube and seals it to the outside. The closure element is preferably designed as a circular plug, the diameter of which interacts with the inner diameter of the hollow tube in such a way that the hollow tube is hermetically sealed.

[0015] The holder has a rotationally symmetrical connection area. The connection area is provided at one end of the holder, which faces the hollow tube. The insulator has a radially circumferential joining area at the upper end relative to the longitudinal axis A of the hollow tube, which is free of silicone shielding. The holder can be connected to the insulator in such a way that the connection area of ​​the holder surrounds the joining area of ​​the insulator in a form-fitting manner, i.e., with a precise fit.

[0016] The improved concept thus offers a connection technology between the post insulator and equipment for high-voltage applications that is detachable, yet stable and easy to install. The bracket can be attached to the post insulators on-site, with or without the equipment for which it is intended. Bonding the bracket to the hollow tube is not required.

[0017] According to one embodiment of the improved concept, the closure element, the hollow tube, and the holder each have at least one transverse bore that is coaxially aligned with one another. A locking bolt can be inserted into the at least one transverse bore and secured therein, for example, with one or more screw nuts. Preferably, two locking bolts are used, arranged perpendicular to one another and one below the other.

[0018] The locking bolt allows the connection to remain detachable. At the same time, the bracket is fixed in place between the locking element and the hollow tube, thereby further strengthening the connection with regard to form-fitting.

[0019] The securing bolt is preferably made of steel, plastic, in particular glass fiber reinforced plastic, or ceramic material.

[0020] According to a further embodiment of the improved concept, the positive connection between the holder and the insulator, in particular the joining area of ​​the insulator, is designed as a conical connection.

[0021] Preferably, the conical connection is designed such that the outer diameter of the hollow tube of the insulator decreases toward the upper end relative to the longitudinal axis A. Accordingly, the inner diameter of the connection area of ​​the holder becomes larger toward the end of the holder facing the hollow tube.

[0022] The conical design of the connection allows the bracket to self-center on the insulator, thus simplifying the installation of the equipment on the support insulators. The conical connection also offers greater strength than a conventional flange connection, particularly when subjected to transverse forces, due to the improved form fit.

[0023] According to a further embodiment of the improved concept, the closure element and the holder are made of a non-metallic material.

[0024] The non-metallic material of the holder is preferably made of fiber-reinforced plastic, particularly preferably glass-fiber-reinforced epoxy resin. The holder can be manufactured, for example, using injection molding, vacuum infusion, and / or winding processes.

[0025] The non-metallic material of the closure element is preferably made of fiber-reinforced plastic, particularly preferably glass-fiber-reinforced epoxy resin. The closure element can be manufactured, for example, by injection molding, vacuum infusion, and / or winding processes.

[0026] Preferably, the non-metallic material of the closure element can also be made of a ceramic material.

[0027] The design of the components from non-metallic material prevents them from heating up due to the magnetic fields surrounding them.

[0028] According to a further embodiment of the improved concept, the holder comprises means for fastening at least one busbar. For this purpose, the holder preferably comprises a first U-shaped recess and a second U-shaped recess opposite the first, which are located outside the connection area and are suitable for receiving a busbar.

[0029] Preferably, the holder for fastening the at least one busbar further comprises a spring element which fixes the at least one busbar in the U-shaped recesses depending on the holder.

[0030] According to a further embodiment of the improved concept, the holder comprises means for securing at least one choke coil. Preferably, the holder comprises a first and a second groove located outside the connection area and suitable for receiving a gear ring.

[0031] According to a further embodiment of the improved concept, the holder forms the lower end of a hollow tube of another insulator relative to a longitudinal axis, or a part of the lower end of the hollow tube of another insulator. Preferably, the insulators are identical to one another. In particular, the insulators together form a multi-part support insulator.

[0032] Further embodiments and implementations of the isolator result directly from the various embodiments.

[0033] The invention will now be explained in detail using exemplary embodiments with reference to the drawings. Components that are identical, functionally identical, or have an identical effect may be provided with identical reference numerals. Identical components or components with identical functions may only be explained with reference to the figure in which they first appear. The explanation is not necessarily repeated in subsequent figures. It shows Fig. 1 an advantageous embodiment of the insulator according to the improved concept in a side view; Fig. 2 a detailed view of the insulator Fig. 1 in a perspective view; Fig. 3 another detailed view of the insulator from Fig. 1 in an exploded view and sectional view; Fig. 4 another detailed view of the insulator from Fig. 1 in a side view and sectional view; Fig. 5 a detailed view of a further advantageous embodiment of the insulator according to the improved concept in a perspective view; Fig. 6 another detailed view of the insulator from Fig. 4 in a side view and sectional view.

[0034] Fig. 1 shows an advantageous embodiment of the insulator according to the improved concept in a side view. The insulator 1 has a substantially rotationally symmetrical hollow tube 2 made of glass fiber reinforced epoxy resin with a silicone shield 3 attached to the circumference of the hollow tube 2. At a lower end 5 relative to a longitudinal axis A of the hollow tube 2, a base flange 4 is arranged, on which the insulator 1 is mounted in a vertical position. At an upper end 7 of the hollow tube 2 opposite the lower end 5, a holder 6 for an operating device for high-voltage applications is fastened. Such operating devices can be, for example, a choke coil supported on one or more insulators by means of a gear ring, or a busbar held at a distance from the ground by the insulator. In the case of the Fig. 1, the holder 6 is provided for a choke coil. A holder for a busbar will be discussed in more detail when explaining another design variant. Another possible device is an additional insulator. In this case, the insulator is composed of several separate insulators that can be connected to one another via the holder 6. The additional insulator then no longer has a base flange; instead, the holder 6 is formed as part of the hollow tube 2 at the lower end 5 of the hollow tube 2.

[0035] Fig. 2 shows a detailed view of the insulator from Fig. 1 in a perspective view. More precisely, the upper end 7 of the insulator 1 with the mounted holder 6 is shown in detail. Visible are the silicone shielding 3, which was applied to the hollow tube 2, as well as the rotationally symmetrical holder 6. In this embodiment, the holder 6 serves to support a choke coil. For this purpose, the holder 6 has two oppositely arranged grooves 14 for receiving a gear ring, as well as several drop-shaped recesses 13 for securing the gear ring and the coil using resin-impregnated fiber bundles that are threaded through the recesses 13.

[0036] Another detailed view of the insulator from Fig. 1 is an exploded view and a sectional view in Fig. 3. Here, the holder 6 is shown separated from the hollow tube 2 in order to clearly illustrate the closure of the hollow tube 2 and the connection between the holder 6 and the hollow tube 2.

[0037] The insulator 1 or the hollow tube 2 has a closure element 8, which is arranged at the upper end 7 of the hollow tube 2 in its inner cavity and is designed as a circular plug, and whose diameter D V is dimensioned such that the plug 8 hermetically seals the end face of the hollow tube 2 and seals it off from the outside environment. The diameter D V is, for example, in a range between 150 mm and 600 mm, preferably between 200 mm and 580 mm.

[0038] The holder 6 comprises a connection area 9 at its end facing the hollow tube 2. This connection area 9 interacts with a radially circumferential joining area 10 arranged at the upper end 7 of the hollow tube 2. The joining area 10 is free of silicone shielding 3 and has an outer diameter D A which, relative to the longitudinal axis A, has a maximum diameter D A maxto the upper end 7 of the hollow tube 2 to a minimum diameter D A min Accordingly, the inner diameter D I of the connection area 9 of the bracket 6 of a minimum diameter D I min towards the end facing the hollow tube 2 to a maximum diameter D I max The difference between the maximum outer and inner diameter D A max , D I max and the minimum outer or inner diameter D A min , D I min , i.e. ultimately the width of the cone, lies in a range between 10 mm and 50 mm, preferably the difference is 20 mm. The minimum outer or inner diameter D A min , D I min can be, for example, 200 mm or 350 mm or 580 mm and the maximum outer or inner diameter D A max , D I max accordingly 220 mm or 370 mm or 600 mm.

[0039] During assembly, the holder 6 is placed on the joining area 10 of the hollow tube 2 so that its connecting area 9 surrounds the joining area 10 in a form-fitting manner, ie completely. This is shown in Fig. 4 in a further detailed view of the insulator from Fig. 1 in a side view and a sectional view. The conical shape of the joining area 10 and the connection area 9 relative to each other ensures that the holder 6 surrounds the hollow tube 2 in its joining area 10 in a form-fitting manner, ie, completely, and can be positioned self-centeringly on the hollow tube 2 during assembly.

[0040] Two transverse bores 11 are provided in each of the holder 6, the hollow tube 2, and the closure element 8 or the plug. The transverse bores 11 are aligned coaxially with each other. A locking bolt 12 is pushed through each of them and secured in the transverse bores 11 by means of two nuts. The locking bolts 12 are preferably made of steel, plastic, in particular glass-fiber-reinforced plastic, or ceramic.

[0041] In the Fig. 5 and Fig. 6 is a detailed view of a further advantageous embodiment of the insulator according to the improved concept, once in perspective ( Fig. 5) and once in a side view and sectional view ( Fig. 6). Isolator 1 essentially corresponds to the previously explained Isolator 1. Therefore, reference is made to the corresponding explanations in an analogous manner. Fig. 4 and Fig.The insulator 1 shown in Figure 5 differs, however, in that the holder 6 is provided for fastening a busbar 15. This concept is used, for example, in transformer substations for fixing busbars, where a certain distance from the ground must be maintained. For this purpose, the holder 6 preferably has a first U-shaped recess 16 and a second U-shaped recess 16 arranged opposite the first, which lie outside the connection area 9 and are dimensioned to accommodate a busbar 15. To fix the busbar 15 in the U-shaped recess 16, a spring element 17, preferably a leaf spring, is provided, which fixes the busbar 15 depending on the holder 6 by pressing the busbar 17 into the U-shaped recess 16 with its spring force.

[0042] The improved concept specifies a connection technology for head fittings of post insulators for high-voltage technology applications. This technology is suitable for connecting a post insulator to an extending pipe geometry, whereby the pipe geometry serves as a holder for a high-voltage equipment. Compared to a conventional flange connection, the improved connection technology offers the advantage of being detachable while still being able to withstand higher forces. The conical connection enables force transmission through frictional and positive locking as well as self-centering during assembly. The locking bolt keeps the connection detachable, but at the same time fixes the holder depending on the closure element and the hollow pipe, thereby additionally strengthening the connection with regard to positive locking. REFERENCE SYMBOL 1 insulator 2 hollow tubes 3 Shielding 4 Foot flange 5 lower end of 2 6 Bracket 7 upper end of 2 8 locking element 9 connection area of ​​6 10 joining area of ​​1 11 Cross hole 12 locking bolts 13 Recess 14 grooves 15 Busbar 16 U-shaped recess 17 Spring element A Longitudinal axis of 2 D A Outer diameter of 10 D A max maximum outer diameter of 10 D I Inner diameter of 9 D I max maximum inner diameter of 9 D V Diameter of 8

Claims

[1] Insulator (1) for high voltage applications comprising - a substantially rotationally symmetrical hollow tube (2) made of glass fibre reinforced epoxy resin, - a shield (3) made of silicone attached to the circumference of the hollow tube (2), - a foot flange (4) at a lower end (5) of the hollow tube (2), - a holder (6) for an operating device for high-voltage applications at an upper end (7) of the hollow tube (2), wherein - the insulator (1) has a closure element (8), a plug, which is arranged inside the hollow tube (2) and closes the front side of the upper end (7) of the hollow tube (2) and seals it off to the outside, wherein - the holder (6) has a rotationally symmetrical connection area (9), - the insulator (1) has a radially surrounding joining area (10) at the upper end (7) of the hollow tube (2) which is free of silicone shielding (3), - wherein the holder (6) is connectable to the insulator (1) in such a way that the connection area (9) of the holder (6) surrounds the joining area (10) of the insulator (1) in a form-fitting manner, wherein - the closure element (8), the hollow tube (2) and the holder (6) each have at least one transverse bore (11) which are aligned coaxially with one another, - a securing bolt (12) can be inserted into at least one transverse bore (11) and fixed therein. [2] Insulator (1) according to claim 1, wherein - the positive connection between the holder (6) and the insulator (1) is designed as a conical connection. [3] Insulator (1) according to one of the preceding claims, wherein - the closure element (8) and the holder (6) are made of a non-metallic material. [4] Insulator (1) according to one of the preceding claims, wherein - the holder (6) has means for fastening at least one busbar. [5] Insulator (1) according to one of the preceding claims, wherein - the holder (6) has means for fastening at least one choke coil. [6] Insulator (1) according to one of the preceding claims, wherein - the holder (6) forms the lower end of a hollow tube of another insulator.

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