EP2431983A1 - High voltage bushing and method for manufacturing same - Google Patents

Abstract

The high-voltage bushing contains in a coaxial arrangement a current conductor (10) guided along an axis (A) and an insulator (20) fastened to the current conductor (10) and encompassing the current conductor (10), and a capacitor coil (40) integrated into the insulator (20). , a mounting flange (30) fastened to the insulator (20) and a shielding (50) which encompasses the insulator (20) and is guided along the axis (A) from the mounting flange (30) to a connection (11) of the conductor (10). A reinforcement with a fiber lap (21) attached to the capacitor lap (40) is integrated into the insulator (20). The fiber (21) and the capacitor winding (40) are embedded in an electrically insulating matrix made of a hardened polymer mass (25). The shield (50) is attached to the reinforcement. The fiber lap (21) and the cured polymer mass (25), which jointly embeds the fiber (21) and the capacitor lap (40), reinforce the insulator (20) and reduce the penetration of moisture. The implementation is therefore characterized by a compact structure and great operational reliability.

Description

TECHNICAL AREA

The present invention relates to a high voltage feedthrough according to the preamble of claim 1. The invention also relates to a method for producing a high voltage feedthrough according to the preamble of claim 8.

A high voltage bushing of the aforementioned type connects a conductor arranged in a metal-clad component of a high-voltage installation and insulated with a liquid or gaseous insulating material from the metal enclosure with an external conductor which is generally insulated by the surrounding air but which is also connected to another insulating means such as For example, a solid, oil or SF ₆ , may be isolated and may be part of a high voltage cable, a cable end closure, a cable sleeve or a gas-insulated switchgear.

A typical embodiment of such a bushing includes a field-controlling capacitor winding which is wound onto a round body designed as a metal solid or hollow cylinder. The capacitor winding comprises an insulating film formed of paper or plastic, into which capacitor pads 41 are inserted at certain intervals during winding. The insertion can be done by inserting metal foils, such as based on aluminum or by printing conductive material on the insulating film. The capacitor pads are then arranged in the form of concentric cylinders. The lengths of the capacitor pads are graded so that the capacitances between two successive pads are substantially equal. Therefore, larger diameter capacitor pads have a shorter length in the axial direction. It is thus achieved with the capacitor winding a finely graded control of an electric field, which in operation of the implementation between a high-voltage potential located at the current conductor and the Metal encapsulation of the component, which is typically designed as a transformer acts.

In the area of the bushing exposed to the ambient air, a portion of the capacitor coil is enveloped by a shield made of a porcelain or a polymer, in particular silicone, for protection against external influences, such as weather, pollution and radiation.

The mechanical installation of the implementation in the component, for example in a transformer, is carried out by means of a mounting flange which is fixed to an insulator containing the capacitor winding.

STATE OF THE ART

Bushings of the type mentioned are described for example in EP 1 284 484 B1 . EP 1 417 689 B1 . EP 1 771 866 B1 and WO 2009/053147 A1 , The bushings described are each intended for installation in a metal housing of a high-voltage electrical apparatus, for example a transformer, and each have a capacitor winding integrated in an insulator. Attached to the insulator is a mounting flange which separates a portion of the capacitor coil located above the mounting flange from a portion of the capacitor coil located below the mounting flange and, after installation of the leadthrough into the apparatus, in an insulator devoid of air, typically oil or SF ₆ , is arranged. A region of these bushings exposed to the surrounding air in each case has a shield which acts as weather and radiation protection and which encloses the section of the capacitor winding located above the mounting flange.

The shielding can be like in EP 1 284 484 B1 and EP 1 771 689 B1 may be integrated into a porcelain insulator or made of silicone and fastened on a fiber-reinforced plastic pipe. But it can also be like in EP 1 417 689 B1 and WO 2009/053147 A1 described immediately extended to the between the mounting flange and a power connector of the implementation Be applied outside surface of the capacitor winding receiving insulator.

PRESENTATION OF THE INVENTION

The invention, as indicated in the claims, the object is to provide a high-voltage bushing of the type mentioned above, which is characterized despite a compact design by a high reliability, and to provide a method by which a high-voltage bushing of the type mentioned can be manufactured in a simple and economical way.

According to the present invention, a high-voltage bushing is provided which has a guided along an axis conductor in a coaxial arrangement and an insulator attached to the conductor and the current conductor insulator, a capacitor integrated in the capacitor capacitor winding with mutually electrically insulated capacitor pads in the radial direction by a the axis wound insulating foil are spaced from each other, a mounting flange fixed to the insulator and a comprehensive insulator, along the axis of the mounting flange to a terminal of the conductor guided shielding. In the insulator a gain is integrated with a wound on the capacitor winding filament winding. The fiber and capacitor windings are embedded in an electrically insulating matrix of a cured polymer mass. The shield is applied to the reinforcement.

When practiced in accordance with the invention, the filament winding and the hardened polymer mass co-embedding the fiber and capacitor windings substantially reinforce the insulator. With the reinforcement formed from the fiber winding and the part of the polymer mass which embeds this winding, a compact construction and a mechanically stable design of the bushing according to the invention are achieved by simple means. In addition, the mechanical stabilization of the capacitor winding significantly reduces its strength reduced by the high brittleness of the cured polymer at low temperatures. At the same time, penetration of moisture is avoided, since the reinforcement surrounding the capacitor winding acts as a diffusion barrier and, if appropriate, keeps diffusing water away from the capacitor winding acting as a device for controlling the electric field by the shielding. An impairment of the electrical properties of the implementation as a result of penetrating into the capacitor winding water is thus avoided. The implementation of the invention is therefore characterized by a high level of reliability.

By integrating the gain in the insulator containing the capacitor winding accounts at the same time an otherwise the capacitor winding stabilizing and at the same time waterproof receiving external insulator and the space between capacitor winding and outer insulator fills, in general liquid insulating.

Depending on the implementation requirements, the reinforcement may be at least partially integrated in at least one of the following sections of the insulator: a section located in an area of the duct exposed to ambient air, a section exposed in a component exposed to insulation Is arranged portion of the implementation, as well as in a guided through the mounting flange section. The fiber wound used in the reinforcement may have at least one guided around the capacitor winding layer of a planar semi-finished fiber product, which advantageously has at least one fabric, a scrim, a mat or a nonwoven.

The capacitor winding may have an impregnating aid guided annularly around the axis, which is applied to the fiber winding and which is formed from a sheet-like insulating material which transmits the polymer compound before hardening. This impregnation aid promotes the impregnation of the fiber coil with a later forming the matrix uncured polymer composition in the manufacture of the implementation. The impregnation aid can be formed from additional turns of the insulating film.

The method according to the invention is used to produce a high-voltage feedthrough, which has a coaxial arrangement along a guided axis along a conductor and one attached to the conductor and the Conductor comprehensive insulator, a capacitor integrated in the insulator capacitor winding with mutually electrically insulated capacitor pads, which are held in the radial direction by an axis wound around the insulating foil from each other, a mounting flange attached to the insulator and an insulator comprehensive, along the axis of the mounting flange a connection of the conductor guided shielding. In this method, the capacitor winding held on the conductor is placed in a mold, dried in the mold and impregnated in the mold with a curable, flowable polymer composition, the polymer composition is cured to form the insulator in the mold, and the mounting flange on a seat attached trained outside surface of the insulator and subsequently applied the shield on the insulator. Before arranging the capacitor winding in the mold, at least one fiber winding acting as reinforcement is applied to the capacitor winding.

With the method according to the invention bushings can be made with a capacitor winding in a particularly economical manner. On the one hand, this is due to the fact that a winding device required for the production of the capacitor winding is at the same time also used to manufacture the fiber winding. On the other hand, the capacitor winding and the fiber body in the mold are dried together, impregnated together with the flowable polymer composition and integrated by curing the polymer composition together in the forming during curing insulator. It is achieved with a few steps a reinforced by the fiber winding, protected from moisture capacitor winding, from which by subsequent attachment of the mounting flange and the shielding a high-quality implementation can be easily made. The manufacture of an additional external insulator of a shielded porcelain or a shielded, fiber-reinforced plastic tube can therefore be omitted in manufacturing technology advantageous manner. Since the reinforcement containing the fiber winding is integrated into the capacitor winding containing the insulator, it is no longer necessary to fill a cavity otherwise enclosed by the additional external insulator with an insulating means increasing the dielectric strength of the leadthrough. At the same time, this is for a mechanical post-processing Reduced effort required because only the time required for attaching the mounting flange seat must be formed by machining in the capacitor winding receiving insulator.

In order to improve the impregnation of the fiber coil, an annular impregnation aid guided annularly around the axis can be integrated prior to the application of the fiber coil, which forms an outer surface of the capacitor coil carrying the fiber wound and which contains a sheet-like semi-finished fiber which passes through the polymer mass before curing.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1

eine Aufsicht auf eine längs einer Achse A erstreckte Ausführungsform einer Durchführung nach der Erfindung, die links der Achse geschnitten dargestellt ist, und,

Fig.2

eine Vergrösserung eines umrandet dargestellten Teils der Durchführung nach Fig.1.

With reference to drawings, the invention will be explained in more detail below. Hereby shows:

Fig.1

a plan view of an along an axis A extending embodiment of a passage according to the invention, which is shown cut left of the axis, and

Fig.2

an enlargement of an outlined portion of the implementation after Fig.1 ,

WAYS FOR CARRYING OUT THE INVENTION

In all figures, like reference numerals designate like-acting parts. In the Fig.1 shown extending along the axis A contains in coaxial arrangement a guided along the axis A current conductor 10, an attached to the conductor and the conductor comprising insulator 20, a mounting flange 30 attached to the insulator 20, a capacitor 20 integrated in the capacitor winding 40 and a the insulator 20 comprehensive shield 50.

The current conductor 10 may, with its lower end, not shown, with a power connection of a conductor arranged in an insulator-filled metal housing conductor of an electrical apparatus, typically a transformer, be electrically connected. Its upper end formed by the power connection 11 can be electrically conductively connected to a generally air-insulated high-voltage conductor.

The shield 50 is guided along the axis A from the mounting flange 30 to a power terminal 11 of the conductor 10. It serves as weather and radiation protection and is formed by an elastomeric polymer, in particular based on silicone or EPDM.

The capacitor winding 40 has mutually electrically insulated capacitor pads 41, which are held in the radial direction by a wound in the form of a spiral insulating film 42, which is typically made of paper and / or plastic, at a distance from each other. The lengths of the capacitor pads 41 above the mounting flange 30, so in an air-exposed portion of the implementation, as well as below the mounting flange 30, so in an insulating the metal-encapsulated apparatus exposed, only partially shown part of the implementation shrink with increasing, radial distance to the conductor 10 steady.

The capacitor winding 40 is used to control an electric field, which forms during operation of the implementation between the then located at high voltage potential conductor 10 and then located at the potential of the metal housing of the transformer mounting flange 30.

In the insulator 20, a reinforcement with an applied to the capacitor winding 40, tubular formed fiber winding 21 is integrated. The reinforcement is at least partially integrated into a portion 22 of the insulator disposed in the part of the duct exposed to ambient air. It can be seen, however, that the reinforcement is also integrated in a section 23 of the bushing guided through the mounting flange 30. Alternatively, the reinforcement can also be integrated in only one of the two sections 22 or 23 or else in a section 24 of the insulator 20 situated below the mounting flange 30, that is to say in a region of the bushing exposed to the insulating means of the transformer. The fiber winding 21 has at least a guided around the capacitor winding 40 layer of a planar fiber semi-finished product, which advantageously contains at least one fabric, a scrim, a mat or a nonwoven. Suitable fibers are inorganic fibers, for example based on glass or basalt, or inorganic fibers, for example based on aramid.

The integrated in the capacitor winding 20 gain supports the generally comparatively brittle capacitor winding 40 and carries on its outside the mounting flange 30 as well as between the mounting flange 30 and power connector 11 extending shield 50th

From the figures it can be seen that in the capacitor winding 40 an annular guided around the axis A impregnation aid 43 is integrated, on which the fiber winding 21 rests. The impregnation aid 43 is also formed from a sheet-like semi-finished fiber which is permeable to a curable polymer composition before curing. It is applied to the insulating film 42, but may also be formed by additional outer turns of the insulating film 42.

The fiber winding 21, the impregnation aid 43, the insulating film 42 and the capacitor pads 41 are embedded in a matrix of the aforementioned, but hardened by curing polymer mass 25. The polymer composition comprises a filled or unfilled polymer, typically based on an epoxy resin. The filler used is generally a powder, for example based on SiO ₂ or Al ₂ O ₃ .

To make the implementation is - as in EP 1 771 866 B1 - described the typically paper or plastic containing insulating film 42 wound on the rotatably mounted conductor 10 to form a spiral and the typically metal foil-containing capacitor pads 41 are inserted during the winding process in the individual turns of the spiral. The case forming capacitor winding 40 is completed by applying at least one turn of the permeable for the uncured polymer composition, planar semi-finished fiber product of the impregnation 43 to the outside.

On the impregnating 43 then the also planar semi-finished fiber of the fiber winding 21 is applied. Optionally, the polymer composition 25 may additionally contain a powdered filler, such as based on quartz. The addition of this filler is facilitated if the insulating film 42 and optionally also the capacitor pads 41 have openings through which the particles of the filler are passed during impregnation with the uncured polymer composition.

The fiber winding 43 carrying capacitor winding 40 is arranged in a mold, not shown, and dried in the mold. After drying, the assembly containing the two dried rolls 40 and 43 is impregnated in the mold with the uncured polymer composition. The in the state of the art, about in EP 1 771 866 B1 or in WO 2009/053147 A1 , described insulating film 42 and optionally also the capacitor pads 41 have permeable pores and channels for the polymer composition. Since the semifinished fiber product of the impregnation aid 43 is permeable to the uncured polymer composition, the capacitor winding 40 is thus quickly impregnated with this polymer composition. The impregnating aid 43 rests with a large surface on the fiber winding 21 of the reinforcement and therefore, regardless of the pore structure of the fiber winding 21 very quickly polymer mass in the opposite its axial extent only a small radial thickness fiber winding 21. The impregnation can even with the use of a high viscosity polymer mass are carried out quickly.

Subsequently, the polymer composition is cured in the mold to form the matrix and thus also to form the insulator 20 - generally at elevated temperatures. Then, a molded body containing the insulator 20 and the conductor 10 attached to the insulator is taken out of the mold. In the insulator 20, a seat for the mounting flange 30 is machined. The mounting flange 30 is typically fixed to the insulator 20 by gluing, cold shrinking or jamming. How out Fig.1 it can be seen, in the seat an annular guided around the axis shoulder 26 may be formed, on which the mounting flange 30 is placed from above and clamped by means of a guided from below against the shoulder 26 pressure ring 31. The required clamping force is guided by axially, off Fig.1 not obvious screws generated, which engage in the mounting ring 30 and press the mounting ring 30 from above and the pressure ring 31 from below against the shoulder 26 when screwing.

The mounting flange 30 carries on the seat supported sealing rings 32. After installation in another mold then the shield 50 - as in WO 2009/053147 A1 described - be made by introducing elastomeric polymer into the mold. The sealing rings prevent after installation of the implementation in the metal housing of the high voltage component, the penetration of air into the interior of the metal housing, respectively. the escape of oil from the housing in the space enclosed by the shield 50 volume.

LIST OF REFERENCE NUMBERS

10

conductor

11

power connection

20

insulator

21

Filament winding

22, 23, 24

Portions of the insulator 20

25

hardened polymer composition

26

shoulder

30

mounting flange

31

pressure ring

32

seals

40

capacitor winding

41

capacitor plates

42

insulation

43

Imprägnierhilfe

50

canopy

A

axis

Claims (11)

High voltage bushing, containing in coaxial arrangement: a current conductor (10) guided along an axis (A), a insulator (20) attached to the current conductor (10) and comprising the current conductor (10), a capacitor winding (40) integrated in the insulator (20) with mutually electrically insulated capacitor pads (41) which are held in the radial direction by a spaced apart from each other about the axis (A) insulating film (42), a mounting flange (30) fastened to the insulator (20) and one comprising the insulator (20) along the axis (A) of the mounting flange (30) to a terminal (11) of the conductor (10) guided shielding (50), characterized in that in the insulator (20) a reinforcement is integrated with a fiber winding (21) applied to the capacitor winding (40), that the fiber winding (21) and the capacitor winding (40) in an electrically insulating matrix of a cured polymer composition ( 25) are embedded, and that the shield (50) is applied to the reinforcement. Feedthrough according to claim 1, characterized in that the reinforcement is at least partially integrated in a section (22) of the insulator (20) which is arranged in an area exposed to the ambient air passage. Feedthrough according to one of claims 1 or 2, characterized in that the reinforcement is integrated in a portion (23) of the insulator (20) which is passed through the mounting flange (30). Feedthrough according to one of claims 1 to 3, characterized in that the fiber winding (21) has at least one around the capacitor winding (40) guided position of a planar semi-finished fiber product. Bushing according to claim 4, characterized in that the semi-finished fiber product comprises at least one fabric, a scrim, a mat or a non-woven. Feedthrough according to one of claims 1 to 5, characterized in that the capacitor winding (40) has an annular about the axis (A) guided impregnating (43) on which the fiber winding (21) is applied, and from a planar, the Polymer mass (25) is formed before hardening permeable insulating material. Bushing according to Claim 6, characterized in that the impregnating aid (43) is formed from additional turns of the insulating film (42). Method for producing a high-voltage bushing, comprising in coaxial arrangement: a current conductor (10) guided along an axis (A), a conductor (20) attached to the conductor and comprising the conductor (10), a capacitor winding (40) integrated in the insulator (20) with mutually electrically insulated capacitor pads (41) which are held in the radial direction by a spaced apart from each other about the axis (A) insulating film (42), a mounting flange (30) attached to the insulator (20) and a capacitor winding (40) comprising, along the axis (A) from the mounting flange (30) to a terminal (11) of the conductor (10) guided shielding (50, in which the capacitor winding (40) held on the current conductor (10) is arranged in a casting mold, dried in the casting mold and impregnated in the casting mold with a curable, flowable polymer mass, in which the polymer composition is hardened in the casting mold to form the insulator (20) and in which the mounting flange (30) is mounted on a seat formed as a seat outer surface of the insulator (20) and subsequently the shield (50) is applied to the insulator (20),
characterized in that prior to arranging the capacitor winding (40) in the mold on the capacitor winding (40) at least one serving as a reinforcement fiber winding (21) is applied. A method according to claim 8, characterized in that prior to application of the fiber winding (21) in the capacitor winding (40) an annularly guided around the axis (A) impregnation aid (43) is integrated, a the fiber winding (21) supporting the outer surface of the capacitor winding ( 40) and which contains a sheet-like, the polymer composition before curing passing semi-finished fiber. Method according to one of claims 8 or 9, characterized in that the fiber winding (21) is at least partially applied to a portion (22) of the capacitor winding (40) which is arranged in a region exposed to the ambient air passage. Method according to one of claims 8 to 10, characterized in that the fiber winding (21) is at least partially applied to a portion (23) of the capacitor winding (40) which is passed through the mounting flange (30).

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