EP1205952B1 - Load switch for a step switch - Google Patents

Abstract

The load switch has a separate oil-filled housing (1) provided with a horizontal upper mounting plate (10), supporting all components of the load switching insert, with the parts of the electrical terminal contacts (21) for each of the switched phases lying within the oil-filled housing supported around the periphery of the upper mounting plate.

Description

The invention relates to a diverter switch for a tap changer with the features of the first claim. Such a diverter switch is known from the documents "tap-changer type R and RM - Inspection Manual" and "tap-changer type R and RM - Technical Data" of the applicant.

Tap changers are known to be used for uninterrupted switching between different winding taps of a tapped transformer and thus for voltage regulation. They usually consist of a selector for powerless preselection of those winding tap of the tapped transformer to be switched to, and a diverter switch for the actual uninterrupted switching from the previously connected winding tap to the new, preselected winding tap. The diverter switch has the necessary for such an uninterrupted, fast switching components, in particular a force storage device, switching contacts - this may be mechanical switching contacts, vacuum switching cells or thyristors -, and means for actuating the switch contacts in a predetermined switching sequence at each switching.

The known diverter switch has its own oil tank, usually in the form of a closed insulating cylinder in which, separated from the surrounding oil of the transformer, all the above components are. Below the diverter switch, the selector is located, which is located in the transformer oil. All components or elements of the diverter switch are designed as a complete diverter switch insert inside the separate oil pan, which can be completely pulled out of the oil pan, for inspection or maintenance, without the entire tap changer from the transformer tank in which it is mounted is, should be removed. The known diverter switch insert has in its upper part a support cylinder made of insulating material which extends concentrically in the installed state within its own oil vessel. The upper end of the support cylinder forms a support plate. At the bottom of the support cylinder, the assemblies of the diverter switch described above are attached, namely the energy storage, including the switching contacts to be actuated, again below in a known manner switching resistors or varistors.

The support plate of the support cylinder is mounted in the assembled state in a corresponding flange on the tap changer head; upwards is a conclusion by the tap changer cover. D. h. That the diverter switch insert of the known diverter switch is completely attached to the support plate of the support cylinder and is fixed thereto with the described flange of the tap changer head. Centric longitudinally through the diverter switch insert extends in a known manner, the drive shaft which actuates the energy storage of the diverter switch, continues to run down to the attached selector and operated there in a known manner, the selector contacts.

To disassemble the diverter switch insert, d. H. for the described extraction from the separate oil vessel, the lid of the tap changer is first removed, then the fastening screws are released, with which the support plate is fixed to the flange, and then the entire diverter switch insert can be lifted to provided for this purpose eyelets on the support plate , The described support cylinder is therefore an important component of the known diverter switch, since the entire diverter switch insert hangs on this support cylinder.

However, this known arrangement has several disadvantages. First of all, it is costly and expensive, since it must be in the support cylinder to a relatively demanding Isolierstoffteil, usually made of GRP, with high mechanical and electrical strength. Furthermore arise through this additional support cylinder electrical voltage problems. Finally, the known arrangement also requires a relatively large amount of space, since, as already explained above, the known diverter switch has two separate insulating cylinder; First of all, the surrounding own closed oil vessel surrounding it, in the upper part of the described support cylinder.

From the DE 36 27 028 A is a diverter switch for a tap changer known having a surrounding him separate oil vessel, in the wall and these are arranged penetrating in horizontal planes for each electrical phase to be switched electrical connection contacts. These connection contacts are used for the load discharge on the one hand and the two sides A and B of the diverter switch, between which switches and the connection to the load dissipation is made. Inside the oil vessel a diverter switch insert is provided, which has a power storage, electrical switching means and switching resistors. In the interior of the oil vessel, a horizontally extending upper bearing plate, which is designed as a base plate, is also provided, which carries all the components of the diverter switch insert. This upper bearing plate is frictionally secured on its periphery on a supporting flange of the transformer housing.

From the FR 901313 A is another tap changer known, wherein a diverter switch insert a diverter switch is fixed by the mating contact pieces form-fitting and non-positively to the reaching into the interior of the oil vessel parts of the connection contacts. This is intended to achieve a simplified assembly or disassembly of the diverter switch insert.

The object of the invention is to further improve the known tap changer and to provide a generic diverter switch, which is simple in construction, requires only a small space and has a high electrical strength.

This object is achieved by a diverter switch with the features of the first claim. The subclaims relate to particularly advantageous developments of the invention.

In the diverter switch according to the invention without the support cylinder, a horizontally extending upper bearing plate is provided in a manner known per se, all the components of the diverter switch insert wearing. This upper bearing plate is attached to its periphery positively and / or non-positively to the reaching into the interior of the oil vessel parts of the connection contacts. According to a further feature of the invention, the terminal contacts of each phase in the assembled state of the diverter switch in the interior of the oil vessel with Dauerhauptkontaktpaaren in combination, each Dauerhauptkontaktpaar upper and lower permanent main contact carrier has, which serve to receive upper and lower permanent main contact fingers. According to a further feature of the invention, the described upper bearing plate at the respective upper permanent main contact carriers of all phases, which are arranged in a circle in a horizontal plane, fixed.

The invention will be explained in more detail by way of example with reference to drawings.

Fig. 1

einen schematischen Längsschnitt durch einen erfindungsgemäßen Lastumschalter, wobei verschiedene - nicht erfindungswesentliche - Bauteile bewusst weggelassen worden sind

Fig. 2

eine vergrößerte Darstellung des Details "A" aus Figur 1.

Show it:

Fig. 1

a schematic longitudinal section through a diverter switch according to the invention, wherein various - not essential to the invention - components have been deliberately omitted

Fig. 2

an enlarged view of the detail "A" from FIG. 1 ,

The in FIG. 1 shown diverter switch has him as a surrounding component in a known manner, a closed oil vessel 1, in which circulates the separate from the transformer oil diverter switch oil. The oil vessel 1 consists of an insulating cylinder, which is closed at the top of the tap changer head 2 and bottom of an oil pan bottom 3. Below the oil pan bottom 3 of - not shown - selector of the tap changer is attached.

Centrally in the interior of the oil vessel 1 extends in the upper region perpendicular to a coupling tube 4. This coupling tube 4 has a coupling flange 5 at the top with a toothing 6. This is in communication with a transmission, not shown, by means of which a rotary motion of a motor drive o. Ä. Is transmitted to the coupling tube. In addition, known shields 7 are provided. At the lower part of the coupling tube 4, a further coupling flange 8 is provided, which establishes the fixed connection to the actual drive shaft 9. This drive shaft 9 extends vertically through the entire diverter switch down.

It is an upper horizontal bearing plate 10 is provided, the attachment will be explained later in more detail. On the upper bearing plate 10, a stator 11 is mounted, which acts as a force storage carrier, that carries the components of a known force accumulator, not shown. These are a tensioned by the rotational movement of the drive shaft 9 elevator part, a releasable output carriage and an actuatable by this output shaft for actuating the also not shown Lastumschalterkontakte. Since such energy storage in a variety of embodiments are familiar to those skilled in the art, said items were not shown in the drawing. It is only indicated an eccentric 12 on the drive shaft 9, the on known manner spans an elevator part. Incidentally, the drive shaft 9 is guided by a bearing 13 in the stator 11 and a further bearing 14 in the upper bearing plate 10.

At a certain vertical distance, a lower bearing plate 15 is provided below the upper bearing plate 10. Between upper bearing plate 10 and lower bearing plate 15 are not shown actual switching contacts of the diverter switch, which are not the subject of the present invention. These switching contacts may be mechanical contacts, vacuum switching cells, thyristors or a combination of different types of contact. These are, depending on the underlying circuit, operated in a predetermined switching sequence after triggering the energy storage.

Shown in the FIG. 1 However, the permanent main contact pairs, which are offset by 120 degrees from each other, are located on the inside of the oil vessel. For each phase to be switched while a permanent main contact pair is provided, of which, however, only two are shown in the sectional view. Each permanent main contact pair consists of an upper permanent main contact carrier 16 and lower permanent main contact carriers 17. Upper permanent main contact fingers 18 are disposed on the upper permanent main contact carrier 16 and lower permanent main contact fingers 19 are disposed on each of the two lower permanent main contact carriers. The wiring is in each case by means of a movable permanent main contact 20, which rolls in succession on the different permanent main contact fingers. These permanent main contact pairs represent in the stationary state, the electrical connection between the respective switched side A or B of the diverter switch and the load dissipation, usually the neutral point, is.

In FIG. 1 For example, the upper terminal 21 for the discharge of a phase is shown. The terminal 21 is electrically connected to the upper permanent main contact fingers 18. Below this, the connection contact 22 for the side A of the diverter switch is shown. This communicates electrically with lower permanent main contact fingers 19 of one side. The further connection contact for side B lies behind it in the horizontal plane and is therefore not visible in the sectional view.

Below the lower bearing plate 15 are not shown overshoot resistors and only indicated varistors 23; their function is well known.

On the oil pan bottom 3, a gear 24 is provided in a known manner, which actuates the selector by means of an insertable into a clutch 25 further drive shaft. At its lower end, the extension of the drive shaft 9 is guided in a bearing 26 in the oil pan bottom 3. For the sake of completeness, it should be noted that a bearing 27 for guiding the drive shaft is also located in the lower bearing plate 15.

Each of the already discussed upper permanent main contact carrier 16 according to the invention has an upper centering bracket 28 with an upwardly directed locking pin 29. Every lower one Permanent main contact carrier 17 has a lower centering bracket 30, each with an upwardly directed centering pin 31.

Each of the locking pins 29 corresponds according to the invention with locking holes 32 on the circumference of the upper bearing plate 10, and each of the centering pins 31 corresponds with centering holes 33 on the circumference of the lower bearing plate 15th

The attachment of the diverter switch insert is effected in that the upper bearing plate 10, on which all components are arranged, is introduced with their locking bores 32 into the respectively corresponding locking pins 29. The upper bearing plate 10 is fixed in a form-fitting manner, on the upper Zentrierbügeln 28 and is fixed in such a way. In order to facilitate the insertion of the diverter switch insert and to prevent tilting, an additional centering by the centering openings 33 on the circumference of the lower bearing plate 15, in which the corresponding centering pins 31 are introduced takes place in a particularly advantageous manner.

In summary, a fixation of the complete diverter switch insert thus takes place in that all its components are fastened to the upper bearing plate 10 and this upper bearing plate 10 by the positive connection of their locking holes 32 in locking pins 29 on fixed terminals of the diverter switch, here at the connection terminal 21 for the load dissipation, are fixed. To lift out the complete diverter switch insert 5 Aushebeösen 34 are provided at the top of the coupling flange.

Claims (3)

1. Load changeover switch for a tap changer, comprising a separate oil vessel (1), which surrounds it and provided in the wall of which and penetrating this are electrical connecting contacts (21, 22), which are circularly arranged in at least one horizontal plane for each electrical phase to be switched, for the load shunt on the one hand and each of the two sides A and B of the load changeover switch, between which there is switching over and the connection to the load shunt is produced, on the other hand, wherein a load changeover switch insert, which in turn comprises a force store, electrical switching means for load changeover switching, means for actuation of the electrical switching means and switchover resistances, is provided in the interior of the oil vessel (1), and wherein a horizontally extending upper mounting plate (10), which carries all components of the load changeover switch insert, is provided in the interior of the oil vessel (1), characterised in that the upper mounting plate (10) is fastened at its circumference in shape-locking and/or force-locking manner to those parts of the connecting contacts (21) which reach into the interior of the oil vessel (1), that the connecting contacts (21, 22) of each phase are connected in the interior of the oil vessel (1) with permanent main contact pairs, wherein each permanent main contact pair has upper and lower permanent main contact carriers (16, 17) for mounting upper and lower permanent main contact contacting fingers (18, 19), and that the upper mounting plate (10) is fastened to the respective permanent main contact carriers (16) of all phases, which are arranged circularly in a horizontal plane.
2. Load changeover switch according to claim 1, characterised in that the upper permanent main contact carriers (16) each have an upper centring yoke (28) with an upwardly directed locking pin (29), and each of these locking pins (29) corresponds with a respective locking bore (32) at the circumference of the upper mounting plate (10) and that the upper mounting plate (10) rests in positionally fixed manner by the underside thereof on the upper centring yoke (28).
3. Load changeover switch according to claim 2, characterised in that a lower mounting plate (15) is provided at a vertical spacing from the upper mounting plate (10), extends parallel thereto and is mechanically fixedly connected therewith, that the lower permanent main contact carriers (17) each comprise a lower centring yoke (30) with a respective upwardly directed centring pin (31) and that each of these centring pins (31) corresponds with a respective centring opening (33) at the circumference of the lower mounting plate (15) in such a manner that an additional fixing is effected.

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