EP1284484B1 - Manufactoring method for a high voltage feedthrough - Google Patents

Description

TECHNICAL AREA

The invention is based on a method for producing a high-voltage feedthrough according to the preamble of patent claim 1. With this method, column-shaped feedthroughs are produced which serve to pass a high-voltage conducting conductor through a grounded housing wall, for example a transformer. Such feedthroughs each have a hollow, cylindrically symmetrical open-air insulator, on whose one end face a feedthrough head executable on high-voltage potential and on whose other end face a counter-current feed-through foot which can be guided to earth potential is mounted. Further, the implementation includes a along the cylinder axis through the open air insulator guided draft tube and attached to the draft tube, field-controlling insulating.

STATE OF THE ART

With the preamble, the invention relates to methods for the production of high voltage feedthroughs, as it has been used by the patent applicant for many years. In this case, a feed-through foot designed as a mounting flange, an outdoor insulator made of porcelain or a dimensionally stable plastic, and a feed-through head with a compression spring are mounted in sequence on a drawtube. This draft tube carries a field-controlling insulating body on which the feed-through foot is supported. With the help of a clamping tool, the lead-through head is held supported with bias on the outdoor insulator. On the guided through the feedthrough head and having an external thread end of the drawbar a nut is screwed until it stops at the feedthrough head. After loosening the clamping tool, the feedthrough head and the Durchführungsfuss via the drawbar and the insulating body positively connected to each other and supported with a specific compression spring by the biasing force on the front sides of the outdoor insulator, so that a cavity located in the interior of the outdoor insulator is sealed to the outside and can be filled with insulating.

PRESENTATION OF THE INVENTION

The invention, as defined in the claims solves the problem of providing a method of the type mentioned, which makes it possible to produce high-voltage bushings with different dimensions and requirements in a particularly economical manner.

In the method according to the invention, a tensioning member which is displaceable in the axial direction is mounted on a pull body on a puller of the feedthrough head, the head flange and the tensioning element are braced against one another to form biasing force, and the puller is subsequently mounted on the pre-stressed feedthrough head the tensioning element is fixed to an end of the pulling body guided by the open-air insulator, and the tensioning element is then released from the head flange to form the tension. These process steps enable a rapid and economical production of the high-voltage feedthrough. The use of an additional clamping tool can also be dispensed with, as well as the provision of comparatively complicated trained and dependent on the dimensions and tasks of the bushings implementing heads.

For manufacturing reasons, it is convenient to attach the clamping element by means of a guided in a threaded through hole of the head plate screw on the head flange. The clamping element can then be very easily operated during assembly of the implementation. At the same time then the clamping element is largely independent of the size of the feedthrough head and can be used in the manufacture arbitrarily sized bushings.

By turning the screw while simultaneously guiding a resting on a spring clamping plate of the clamping element against the head flange can be generated in a simple and secure manner with a screwdriver necessary for the assembly bias.

It is advisable to unscrew the preloaded bushing head with an internal thread provided on the clamping plate on an external thread of the tractor and wind up to the stop on the outdoor insulator on the traction body. It can be used for a conventional production and therefore already existing external thread and at the same time eliminates otherwise necessary tools for the production of the pre-assembled implementation.

The implementation can now be finished easily. With a screwdriver, the screw is loosened and so automatically the head flange and the feedthrough foot on the prestressed spring, the clamping plate, the tension body and fixed to the traction body, field-controlling insulating fixed to the outdoor insulator.

Since the mating thread of the screw is designed as a through hole, the interior of the bushing can be filled with insulating material after removing the screw via this hole. The attachment of an additional filling opening for the insulating can be omitted.

A safe completion of the inside of the bushing is achieved if the threaded through hole is closed after filling the insulating means using a suitable sealing screw.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine Seitenansicht einer nach dem erfindungsgemässen Verfahren hergestellten und rechts einer Längsachse axial geschnitten dargestellten Hochspannungsdurchführung, und

Fig. 2

eine Aufsicht auf einen Schnitt durch einen vorgespannten Durchführungskopf vor dessen Einbau in die Hochspannungsdurchführung gemäss Fig.1.

The invention will be explained below with reference to exemplary embodiments. It shows:

Fig. 1

a side view of a prepared according to the inventive method and right axial axis of a longitudinal axis shown high voltage feedthrough, and

Fig. 2

a plan view of a section through a prestressed feedthrough head before its installation in the high voltage bushing according to Fig.1.

WAYS FOR CARRYING OUT THE INVENTION

In the two figures, like reference numerals designate like-acting parts. The high-voltage bushing shown in Fig. 1 is designed in the manner of a column and has a hollow, cylindrically symmetrical outdoor insulator 1. This insulator is made of a dimensionally stable, weather-resistant material, preferably a plastic based on a tube made of a fiber-reinforced composite material and a Silikonschirmirmung or a porcelain. On its upwardly facing end face, it carries a metal feedthrough head 2 which can be guided to high voltage potential. At its downwardly pointing, oppositely arranged end face, the outdoor insulator is carried by a metal feedthrough foot 3 which can be guided to earth potential.

Along the vertically aligned axis 4 of the open-air insulator 1, a cylindrically symmetrical metal traction body 5 is guided, which - as shown - may be formed as a tube 5 or as a solid bolt. In its formation as a draw tube 5 of the tension body is the recording of a high-voltage cable end, which is fixed electrically conductively with a cable bolt at the upper end of the drawbar. If the tension body is designed as a bolt, then this bolt can guide the otherwise flowing in the cable end current.

It can be seen on the outer surface of the drawbar 5, a field-controlling, preferably designed as a capacitor bushing, insulator 6 is fixed. The insulating body 6 has an upper predominantly cylindrical and a lower predominantly conical section on. The cylindrical portion is disposed inside the outdoor insulator 1 and serves to control the electric field of a guided during operation of the implementation of the draft tube 5, high-voltage conductor in the region of the outdoor insulator 1 and the feedthrough foot 3. The conical section is in operation of the implementation in one arranged with the feed-through foot 3 electrically conductive housing, such as a transformer, and controls the electric field of not shown in Figure 1, high-voltage-carrying conductor in the housing interior. Between two sections, the field-controlling insulating body 6 includes a shoulder 7 on which the passage foot 3 is supported. The two ends of the drawbar 5 are led out of the interior of the implementation. In the upper end of the drawbar 5, an external thread 51 is inserted, which cooperates with two not shown in Figure 1 internal threads for a clamping element 21 of the feedthrough head 2 and for a mounting device 8 for holding a final bolt drawn in operation of the implementation of the draft tube 5, high-voltage conductor. At the lower end of the drawbar 5, a spherical control electrode is attached, which is used for the homogenization of the electric field of the drawn into the drawbar 5 conductor.

To make the implementation of the bushing foot 3 and the outdoor insulator 1 are mounted in order on the draft tube. The bushing foot 3 is then supported on the shoulder 7 of the field-controlling insulating body 7 and the lower end face of the outdoor insulator 1. Subsequently, the feedthrough head 2 is mounted on the drawbar 5. When mounting the clamping element 21 is attached to a flange 22 of the feedthrough head 2, that between clamping element 21 and head flange 22 a defined biasing force acts.

2, the structure of the prestressed bushing head 2 is shown. It can be seen in the head flange 22 of the feedthrough head two threaded through holes are recessed, in each of which one of two mounting screws 23 is guided, and the clamping element 21 a resting on the head flange plate spring 24 and a plate spring 24 compressing clamping plate 25. The clamping plate 25 does not contain two designated, aligned in the direction of the axis 4 bearing bushes, in each of which one of the two mounting screws 23 is rotatably mounted. In the clamping plate 25, an internal thread 26 is further inserted.

Before mounting the feedthrough head 2 onto the draw tube 5, the two mounting screws are screwed into the head flange 22. The clamping plate 25 is guided downwards and thus compresses the cup spring 24 resting on the top flange 22.

The same effect can be achieved with a single mounting screw or with more than two mounting screws. It is important, above all, that the clamping plate is displaceable in the direction of the axis 4. If only one screw 23 is provided, then a one-sided biasing force should be compensated by a guide pin, which is used instead of the second mounting screw 23.

The thus pre-tensioned with a defined force feed-through head 2 is now also drawn onto the drawtube 5. Here, the internal thread 26 of the clamping plate 25 is screwed onto the external thread 51 of the drawbar 5 and threaded onto the drawbar 5 until it stops at the outdoor insulator 1. When loosening the screw, the prestressed plate spring 24 expands in the axial direction and leads the clamping plate 25 upwards. During this movement, the tensioning plate 25 via the thread 26, 51 firmly connected to the draft tube 5 and in turn firmly connected to the drawbar field-controlling insulating 6 are guided upward. It will be the head flange 22 of the feedthrough head 2 and the feedthrough foot 3 against each other via the plate spring 24, the clamping plate 25, the draw tube 5 and the insulating body 6 clamped fixed to the front sides of the outdoor insulator 1.

A remaining inside the implementation and essentially of the insulating body 6 and the inner walls of outdoor insulator 1, head flange 22 and bushing foot 3 limited cavity 9 is filled for dielectric reasons with an insulating agent, such as a silicone oil. This insulating means can be filled after complete removal of the two mounting screws 23 in a simple manner by one of the threaded through holes. For the Leakage of the cavity 9 provide in Figure 2 unspecified gaskets, between the draft tube 5 and head flange 22 and not shown in the figures sealing rings between outdoor insulator 1 and insulator 6 and head flange 22 and Durchführungsfuss 3. The present in the cavity 9 air can hereby the other of the two threaded through holes are removed. After filling the cavity 9, the threaded through holes can be closed with sealing screws.

LIST OF REFERENCE NUMBERS

1

Outdoor insulator

2

Bushing head

3

Bushing foot

4

axis

5

Zugkörper, draft tube

6

insulator

7

shoulder

8th

end bolt

9

cavity

21

clamping element

22

head flange

23

Mounting screws

24

Belleville spring

25

chipboard

26

inner thread

51

external thread

Claims (7)

1. Method for production of a high-voltage bushing, which is in the form of a column, having a hollow, cylindrically symmetrical outdoor insulator (1), a bushing head (2) which is supported on one end face of the outdoor insulator and can carry high-voltage potential, a bushing foot (3) which is supported on the opposite end face of the insulator (1) and can carry ground potential, a tension body (5) which is passed through the outdoor insulator (1) along the cylinder axis (4) and can carry high-voltage potential, and having a field-controlling insulating body (6), which is attached to the tension body, in which method the bushing foot (3), the outdoor insulator (1) and the bushing head (2) are drawn in sequence onto the tension body (5), the bushing foot (3) is supported on the insulating body (6), and the bushing head (2) and bushing foot (3) are braced with respect to one another via the tension body (5), characterized
   in that, before the bushing head (2) is drawn onto the tension body (5), a tensioning element (21), which can be moved in the axial direction, is fitted to a flange (22) of the bushing head (2),
   in that the head flange (22) and the tensioning element (21) are braced with respect to one another forming a prestressing force,
   in that, when the prestressed bushing head (2) is subsequently drawn onto the tension body (5), the tensioning element (21) is fixed at one end, which is passed through the insulator (1), of the tension body (5),
   and
   in that the tensioning element (21) is then released from the head flange (22), forming the bracing.
2. Method according to Claim 1, characterized in that the tensioning element (21) is fitted on the head flange (22) by means of a screw (23) which is passed through a threaded hole through the head flange (22).
3. Method according to Claim 2, characterized in that the prestressing force is formed by turning the screw (23) while at the same time guiding a tensioning plate (25), which rests on a spring (24), of the tensioning element (21) with respect to the head flange (22).
4. Method according to Claim 3, characterized in that the prestressed bushing head (2) is screwed by means of an internal thread (26), which is provided on the tensioning plate (25), onto an external thread (51) of the tension body (5), and is screwed onto the tension body (5) until it reaches a stop against the outdoor insulator (1).
5. Method according to Claim 4, characterized in that the head flange (22) and the bushing foot (3) are fixed on the outdoor insulator (1), braced with respect to one another via the prestressed spring (24), the tensioning plate (25), the tension body (5) and the insulating body (6), by releasing the screws (23).
6. Method according to Claim 5, characterized in that the screws (23) are removed, and in that the interior of the bushing is filled with dielectric via the threaded hole through the head flange.
7. Method according to Claim 6, characterized in that the threaded hole through the head flange is sealed with the aid of a sealing screw after the introduction of the dielectric.

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