WO2012107309A1

WO2012107309A1 - On-load tap changer

Info

Publication number: WO2012107309A1
Application number: PCT/EP2012/051433
Authority: WO
Inventors: Dieter Dohnal; Christian Hammer
Original assignee: Maschinenfabrik Reinhausen Gmbh
Priority date: 2011-02-12
Filing date: 2012-01-30
Publication date: 2012-08-16
Also published as: EP2673791A1; BR112013017920A2; RU2013141800A; CN103380471A

Abstract

The invention relates to an on-load tap changer arranged in an oil vessel, comprising a selector and a load transfer switch for the uninterrupted switching between various winding taps of a tap-changing transformer. The load transfer switch comprises at least one switching unit, consisting of at least two contact gaps for switchably connecting, in an electrically conductive manner, to at least one respective electric contact element. According to the invention, at least parts of the load transfer switch unit rotate during switching. In addition, the contact elements are arranged circumferentially in a plane, wherein each of the one or more switching unit(s) is/are not associated with a defined phase.

Description

step switch

The present invention relates to a tap changer, comprising a selector and a diverter switch for uninterrupted switching between different winding taps of a tapped transformer with the features of the independent claim.

A diverter switch is known for example from DE 44 07 945 C1. The diverter switch disclosed in the DE patent comprises switching contacts whose switching can be initiated by the sudden release of a force accumulator. The connection of the first and the second switching contact with the load dissipation via separately operable Vakuumschaiter. When switching between different stages, the entire switching unit rotates in the oil tank. Most are fixed contacts on the housing or vessel of the diverter switch, which make the electrically conductive contact with the winding taps. Moving contacts on the switching unit may also make contact with each of the level contacts on the oil pan. Typically, the phases are arranged in several levels one above the other. The winding taps of a tapped transformer to be switched can be connected to the contacts mounted in the oil tank. However, an increasing number of contacts on the circumference of the oil reservoir of the diverter switch leads to restrictions in the

Dielectric strength, since the distances of the contacts from each other are often insufficient for a sufficiently high dielectric strength.

It can also be provided that, in these tap changers, which operate on the so-called, load selector principle, the entire switching unit rotates in the oil vessel. Usually, the tap changers are equipped with load selection principle with a mechanically simple to implement energy storage.

Tap changers already known from the prior art may further comprise a selector. The selector is used for powerless preselection of that winding tap of the tapped transformer to be switched to. In the known from the prior art load switches with voters the diverter switch can be arranged in a separate oil tank. The two voters will become one phase typically performed on two contacts on the oil pan. When switching between different winding taps of the tapped transformer switches

Diverter between these two contacts back and forth, even if the selector continues to turn in one direction. This requires a complex drive of

Diverter switch. The object of the invention is to provide an improved diverter switch with selector available, which avoids the known from the prior art disadvantages. In particular, the object of the invention is to increase the dielectric strength between the winding taps of the tapped transformer and the variable switchability in both directions of rotation.

This object of the invention is achieved by a tap changer with the features of claim 1. Features of advantageous developments of the invention can be found in the subsequent dependent claims. To achieve the object mentioned, the invention proposes a tap changer, which has at least one selector and a diverter switch for uninterrupted switching between different winding taps of a tapped transformer, wherein the diverter switch comprises at least one switching unit, which is also sometimes referred to as switching sector, and at least two Switching sections such as. Vacuum cells, so-called.

Ölschaltstrecken, thyristor stages, etc. is formed. According to the invention it is provided that at least rotate parts of the diverter switch when switching, the

Contact elements are arranged circumferentially in a plane. The at least one

Switching unit is in each case not, as in the prior art, associated with a defined phase, but each moving contact in the on-load tap-changer can basically have contact with all fixed contacts of all phases, for example. By rotation in the same direction.

The tap changer according to the invention provides a very high dielectric strength, which is achieved, inter alia, that the diverter switch is separated as a structural unit from the selector, the entire diverter switch or individual assemblies thereof rotate as in known stage switches on the load selector principle in a circle. The at least one, but in one embodiment, three (or possibly more), phase is preferably arranged circumferentially in a common plane on the circumference of the diverter switch vessel. As in the previously known tap changers according to the load selector principle, a rotary energy store can be used in an advantageous manner, because such can be combined well with the rotating load changeover unit. In a preferred embodiment, typically only two contacts per phase, ie current-carrying and preselected stages, at the periphery of

Diverter oil tank mounted. In the case of a three-phase diverter switch, correspondingly more contacts are distributed around the circumference, in this case a total of six contacts. Basically, various embodiments of the switching unit are possible according to the nature of the present invention, e.g. Circuits with two, three or more switching paths. In a circuit with, for example, two

Switching sections, the switching paths of a switching element and a selectively connected in series over-resistance and another optional in

Row switched to switching element consist. In this case, the further switching element may also have a different physical action principle than the first switching element.

Corresponding configurations may also be provided in a circuit with three or more switching paths. Basically, the switching distances are variable; For example, so-called oil switching paths, vacuum cells, electronic switching elements, e.g.

Thyristors, IGBT etc. can be usefully used and possibly also combined with each other. Also, more switching paths or switching elements per phase are conceivable.

The space available with the arrangement according to the invention and the thus created increased distance between the contacts leads to the

desired increased withstand voltage between the respective preselected and current-carrying winding taps of the tapped transformer. Basically, the switching units or switching paths of the load switching unit are not permanently assigned to a phase, but each moving contact can, depending on the switching position contact with all fixed contacts all phases have, for example. By rotation in a constant

Direction.

The structure of the on-load tap-changer according to the invention sees a total of two

Main assemblies or functional groups before, namely the diverter switch and the selector. The diverter switch is arranged in an oil vessel, for example in a closed insulating cylinder. The diverter switch is provided for switching between at least two stages, for example between at least two

Winding taps of the tapped transformer. Also, the diverter switch can be provided for switching between a plurality, for example, to switch between two or three stages. Furthermore, the diverter switch comprises at least one Switching unit consisting of at least two switching sections. The switching paths may have, for example, a vacuum cell and / or an electronic switching element, such as a thyristor or an IGBT. If an electrically conductive connection to be made, so are the two switching sections in

Surface contact with one electrical contact element. The electric

Connection can be made for example by rapid switching of the switching elements via a spring force or other energy storage. Also, one is outside the

Selector device arranged for oil vessel, which is used for switching between the at least two winding taps of the tapped transformer with the

Diverter switch can be brought into operative connection. The selector device can have, for example, a selector gear and / or a fine selector and / or a preselector (turner or coarse selector).

In a preferred embodiment of the present invention, the at least one switching unit with the at least two switching sections can be arranged in a rotationally fixed manner on a shaft which can be actuated in two opposite directions of rotation.

For example, the rotation about a shaft extending through the linear axis clockwise and counterclockwise done. Also, the two electrical

Circular contact elements and be arranged with a plurality of contact parts around the shaft, so that by means of a rotary movement of the switching shaft an electrically conductive

Connection between the least one switching unit and the electrical

Contact elements can be produced.

According to another preferred embodiment of the present invention, however, it is also possible to arrange the at least one switching unit stationary and rotatably provide the electrical contact elements in a cylinder, so that by a rotational movement of the cylinder, an electrically conductive connection between the at least one switching unit and the electrical contact elements can be produced. The connection of the electrical contact elements with the stationary lines to the selector can be done in this case preferably via sliding contacts.

In addition, an electrical connection of at least one switching path of at least one switching unit via a resistor and / or via a vacuum switching cell can be produced. For example, a switching path can have a resistor, while the further switching path has no additional resistance. The

( Resistors may have a variety of resistance values known to those skilled in the art and, for that reason, are not explicitly mentioned. Also, in a further embodiment of the present invention at least three switching units each having at least two switching paths may be provided, wherein the at least three switching units are formed during a rotational movement of the shaft for at least approximately time-synchronous production of an electrically conductive connection between the three switching units and the electrical contact elements.

Furthermore, each switching unit may comprise at least two switching paths with resistance and at least one load switching path. The at least two switching paths with resistance can be brought into surface contact with an electrical connection with one electrical contact element each. Also, the switching paths with resistance and / or the at least one load switching path can have a total of at least three vacuum interrupters, which can be switched in a defined time offset. For example, first the first vacuum interrupter of the first switching path can be switched with resistance and then the second vacuum interrupter of

Lastschaltstrecke and then the third vacuum interrupter of the second switching path with resistance. Also, the two vacuum interrupters of the switching sections with

Resistor so time shifted to each other switch that they are open at any time simultaneously.

In a preferred embodiment of the present invention, exactly three first and exactly three second electrical contact elements and exactly three switching elements may be present, which are arranged in a circle and offset by 120 ° about the central switching shaft of the diverter switch. Thus, a switch between at least two stages is possible in a simple manner, always in the same way and

preferably takes place in the same time offset, regardless of the selected direction of rotation of the drive shaft. In this case can be dispensed with a complex mechanical rectification or reversal of direction in the switching operation.

The invention will be explained in more detail with reference to embodiments using the drawings described below. The embodiments described below of the circuits and the coordinated switching operations and sequences of the mechanical switching elements and

Vakuumschaltröhren are not limiting, but are used for Explanation of the functions and the switching options of a diverter switch according to the invention a tap changer.

Fig. 1 shows a schematic view of a tap changer according to the invention with oil reservoir and selector

Fig. 2 shows a circuit diagram with the various components of the diverter switch 10, which can be rotated and switched by means of a central switching or drive shaft 8.

Fig. 3 shows in several circuit diagrams, the interconnection of individual switching branches of a plurality of switching elements of the tap changer according to the invention and the switching sequences when rotating a switching shaft. Fig. 4 shows an alternative embodiment of a diverter switch as may be used in the present invention.

Fig. 1 shows a schematic view of a tap changer 1 according to the invention with oil vessel 3 and selector 5. At the oil vessel 3, a lid 4 is arranged. The

Selector 5 may, for example, a selector gear, a fine selector and a preselector (not shown). Further, as shown in FIG

Embodiment shown, a separation point 7 between the oil vessel 3 and selector 5 may be present. In or on the oil vessel 3, other components, such as

For example, a spring energy storage (not shown) may be arranged.

Fig. 2 shows a circuit diagram with the various components of the diverter switch 10, which can be rotated and switched by means of a central switching or drive shaft 8. The switching operation can take place by means of rotation of the drive shaft 8 im- or counterclockwise. The diverter switch 10 shown in FIG. 3 on the basis of several block diagrams is used for uninterrupted switching between two electrical contact elements 12 and 14 of a tap changer 1 (see FIG. 1), which has a selector 20 with winding taps, here exemplified by n and n + 1 Control winding 21 of a tapped transformer can be connected. Of the

Dimmer switch 10 includes a plurality of switching units 17a, 17b and 17c each having a load switching path 18 and two switching paths each with resistor 19. The load path 18 of the respective switching unit 17a, 17b and 17c extends centrally between the two switching paths with resistor 1 9. One of the two switching paths with resistor 19 of the switching unit 17a, 17b and 17c can each have a series circuit of a vacuum interrupter TTV _a and a mechanical switching contact TTF 1 and a resistor R ^ be formed. Likewise, a further switching path with resistor 1 9 of the Schaiteinheit 17 a, 17 b and 17 c respectively via a series circuit of a

Vacuum stop tube TTV _b and a mechanical switching contact TTF ₂ and a resistor R _{2 may be} formed. In addition, the load path 18 of a respective

Switching unit 17a, 17b and 17c from a series circuit of a vacuum interrupter MSV, and a mechanical switching contact MTS- be formed.

The three vacuum interrupters MSV TTV _a and TTV _b and the three mechanical

Switching contacts TTF ₍ MTS and TTF ₂ are shown in FIG. 3 with a defined time

Offset switchable. As can be seen with reference to FIGS. 3 a and 3b, the vacuum interrupter TTV _b arranged in the first resistance branch 19 first opens, with a short time offset, the associated mechanical switching contact TTF ₂ rotating in the same path 19, a switching operation from the first electrical contact element 2 to second electrical contact element 14 causes (see Figure 3b and Figure 3c). Next, as shown in FIG. 3c and FIG. 3d, the second vacuum interrupter MSV ^ located on the path 18 opens before the mechanical switching contact MTS- located in the same path 18 is released (see FIG. 3c - FIG. 3f). As can be seen from FIGS. 3e to 3f, while the second vacuum interrupter MSVT is still open, the first vacuum interrupter TTV _b is closed again, so that an electrically conductive

Connection is made.

To disconnect the electrical connection, the third vacuum interrupter TTV _{a of} the third path 19 is opened in a next step (see FIG. 3f). As shown in FIG. 3g and FIG. 3h, the load path 18 is continued in the direction of the second contact element 14 and the vacuum interrupter MSV arranged on the load path is closed (FIG. 3h). Figures 3i to 3k show the closing of the arranged on the third path 1 9 vacuum interrupter TTV _a and the continuation of the path 19 to the second electrical contact element 14. Figures 31 to 3u show a further switching step and the continuation of the switching unit 17 a, 17 b and 17 c and the paths 18 and 19 from the second contact element 14 to the first contact element 12. It can be seen here that the switching units 17a, 17b and 17c are not fixed to a specific phase but each switching element of each switching unit 17a, 17b and 17c can basically make contact with all fixed contacts of each phase, which takes place for example by a rotation in the same direction. The course of the

Switching operation is identical to the switching operation of Figures 3a to 31 here.

Overall, six switching operations are provided by a respective first contact element on a second contact element for a rotation through 360 °.

The illustration of FIG. 4 finally shows a variant of the tap changer 1, in which at least in the load path 18 with the second vacuum interrupter MSVT and the

mechanical switching contact MTS _1, an additional main contact MC is arranged, which can take over the continuous current.

However, according to the essence of the present invention, it is also possible to arrange the at least one switching unit 17a, 17b and 17c stationary and to provide the electrical contact elements 12 and 14 rotationally fixed in a cylinder, so that by a rotational movement of the cylinder an electrically conductive connection between the at least a switching unit 17a, 17b and 17c and the electrical contact elements 12 and 14 can be produced. The connection of the electrical contact elements 12 and 14 with the fixed lines to the selector 20 may in this case preferably via

Sliding contacts take place.

The invention has been described with reference to a preferred embodiment

described. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

LIST OF REFERENCE NUMBERS

1 tap changer

3 oil container

4 lids

5 dialer

7 separation point

8 drive shaft

10 diverter switch

12 First contact element

14 second contact element

17 switching unit

18 load switching path

19 switching path with resistance

20 voters

21 control winding

n winding tapping n + 1 winding tapping

MSV1 vacuum interrupter

TTV vacuum interrupter

MTS mechanical switch contact

TTF mechanical switching contact

R resistance

Claims

claims

1. tap changer (1), comprising a selector (5) and a diverter switch (10) for uninterrupted switching between different

Winding taps (n, n + 1, n + 2, n + x) of a tapped transformer, wherein the diverter switch (10) at least one switching unit (17a, 17b, 17c), comprising at least two switching paths (18, 19), comprises switchable electrically conductive connection with in each case at least one electrical contact element (12, 14), which via a selector (20) with the corresponding winding tap (n, n + 1, n + 2, n + x) of the tapped transformer is connectable, wherein at least parts of the diverter switch (10) rotate during switching, wherein the contact elements (12, 14) are arranged circumferentially in a common plane, and wherein the at least one switching unit (17a, 17b, 17c) is not assigned to a defined phase.

2. Tap changer according to claim 1, wherein the at least one switching unit (17a, 17b, 17c) comprises two switching paths (18, 19).

3. Tap changer according to claim 1, wherein the at least one switching unit (17a, 17b, 17c) comprises three switching paths (18, 19).

4. Tap changer according to one of claims 1 to 3, wherein the switching paths (18, 19) variably as Ölschaltstrecken and / or vacuum cells and / or as

electronic switching elements, such as thyristors o. The like. Are formed.

5. Tap changer according to one of claims 1 to 4, wherein the at least one switching unit (17a, 17b, 17c) with the at least two switching paths (18, 19) rotatably on an operable in two opposite directions of rotation central switching shaft (8) is arranged, and wherein the at least two electrical contact elements (12, 14) are arranged in a circle around the shaft (8), so that by means of a rotary movement of the shaft (8) an electrically conductive connection between the at least one switching unit (17a, 17b, 17c) and the corresponding electrical contact elements (12, 14) can be produced. Step switch according to one of claims 1 to 4, wherein the at least one switching unit (17a, 17b, 17c) is arranged stationary and the electrical

Contact elements (12, 14) are rotatably provided on a rotatably mounted cylinder, so that by means of a rotary movement of the cylinder, an electrically conductive connection between the at least one switching unit (17a, 17b, 17c) and the electrical contact elements (12, 14) can be produced.

Tap changer according to claim 6, wherein the conductive connection of the electrical contact elements (12,14) with the fixed lines to the selector (20) are designed as sliding contacts.

Tap changer according to one of claims 1 to 7, wherein an electrical connection of at least one switching path (18, 19) at least one

Switching unit (17a, 17b, 17c) via a resistor (Ri, R ₂ ) and / or via a vacuum switching cell (SV ,, TTV _a, TTV _b ) can be produced.

Tap changer according to one of claims 1 to 8, wherein at least three

Switching units (17a, 17b, 17c) each having at least two switching paths (18, 19) are provided and wherein the at least three switching units (17a, 17b, 17c) during a rotational movement of the shaft (8) for at least approximately time-synchronous production of an electrically conductive connection between the three switching units (17a, 17b, 17c) and the electrical contact elements (12, 14) are formed.

Tap-changer according to Claim 9, in which the switching paths with resistor (19) and / or the at least one load-switching path (18) have altogether at least three vacuum interrupters (MSVi, TTV _a, TTV _b ) which can be switched in a defined time offset.

Tap changer according to Claim 10, in which the two vacuum interrupters (TTV _a ; TTV _b ) of the switching paths with resistor (19) are shifted in time with respect to one another and are not simultaneously opened at any time.

12. Stufenschaiter according to one of claims 1 to 1 1, in which exactly three first and / or exactly three second electrical contact elements (12, 14) and / or exactly three switching units (17a, 17b, 17c) are present, the circular and order 120 ° offset around the central switching shaft (8) of the diverter switch (10) are arranged