WO2020249391A1

WO2020249391A1 - On-load tap changer

Info

Publication number: WO2020249391A1
Application number: PCT/EP2020/064552
Authority: WO
Inventors: Silke Wrede; Andreas Sachsenhauser
Original assignee: Maschinenfabrik Reinhausen Gmbh
Priority date: 2019-06-12
Filing date: 2020-05-26
Publication date: 2020-12-17
Also published as: CN114127878A; KR20220008356A; EP3970172A1; JP2022536704A; DE102019115970A1

Abstract

The invention relates to an on-load tap changer (1) for uninterrupted switching between winding taps (N₁,...N_j,..., N_n) of a step transformer (2). The on-load tap changer (1) comprises a selector (3) and a load transfer switch (4). The load transfer switch (4) consists of a first load branch (5.1) and a second load branch (5.2), each load branch (5.1, 5.2) having at least one vacuum interrupter (6.1, 6.2, 7.1, 7.2). Each vacuum interrupter (6.1, 6.2, 7.1, 7.2) can switch between an open state, in which the movable contact (11) and the fixed contact (12) do not touch, and a closed state in which the movable contact (11) and the fixed contact (12) touch in at least one contact point (13). Starting from the contact point (13), each vacuum interrupter (6.1, 6.2, 7.1, 7.2) has a defined spherical region (14). The load transfer switch (4) is designed in such a way that the vacuum interrupters (6.1, 6.2, 7.1, 7.2) are arranged in a housing (29) in such a way that parts of the load transfer switch (4) through which current flows are arranged outside the defined region (14).

Description

LEVEL SWITCH

The invention relates to an on-load tap-changer for uninterrupted switching between winding taps of a tapped transformer.

Known on-load tap-changers usually consist of a selector for the powerless selection of the respective winding tap of the transformer to which the switch is to be made, and a load switch for the actual load switching from the previous winding tap to the new, selected winding tap. Switching is done by mechanical actuation of different switches. With increasing loads, i.e. higher currents and voltages, the requirements placed on the actuation mechanism are also increased.

It is therefore the object of the present invention to provide an improved on-load tap-changer which withstands the increased mechanical and electrical loads at higher currents and voltages.

This object is achieved by the subject matter of independent claim 1. Further embodiments are the subject of the dependent claims.

According to the improved concept, an on-load tap-changer for uninterrupted switching between winding taps of a tapped transformer is specified, which has a selector for powerless preselection on a selected winding tap to be switched to, and a diverter switch for the actual load switching from the previous winding tap to the preselected winding tap . The diverter switch comprises a first and a second load branch and at least one vacuum interrupter in the first and second load branch. Each vacuum interrupter has a movable contact and a fixed contact and can have an open state in which the movable contact and the fixed contact do not touch, and a closed state in which the movable contact and the fixed contact are in at least one point of contact touch, ingest. Starting from the point of contact, each vacuum interrupter has a defined, spherical area. The vacuum switching tubes of the diverter switch are arranged in a housing such that parts of the diverter switch through which current flows are outside the defined range. According to at least one preferred embodiment, the diverter switch is designed in such a way that when the vacuum interrupters are actuated from the closed supply stood in the open state those parts of the diverter switch, which at that time point are flowing through current, are arranged outside the defined area.

Despite the increased currents and voltage, this arrangement allows a compact construction of the on-load tap-changer with reliable operation.

According to at least one embodiment, the spherical area around the contact point has a radius of at least 80 mm and at most 200 mm.

According to at least one embodiment, current-carrying parts of the diverter switch are a first electrical line of the first load branch and / or a second electrical line of the second load branch and / or a third electrical line of the first load branch and / or a fourth electrical line of the second load branch and / or electrically conductive connecting elements and / or a first mechanical switching contact and / or a second mechanical switching contact and / or transition resistors and / o the vacuum interrupters in the closed state, which are arranged outside the spherical loading area of a vacuum interrupter.

According to at least one embodiment, the first load branch of the diverter switch comprises a first vacuum interrupter and a second vacuum interrupter.

According to at least one embodiment, at least the first line, the second line, the second vacuum interrupter of the first load branch, a third line and the first mechanical switching contact are arranged outside the defined area of the first vacuum interrupter of the first load branch.

According to at least one embodiment, the second load branch of the diverter switch comprises a first vacuum interrupter and a second vacuum interrupter.

According to at least one embodiment, at least the first line, the second line, the second vacuum interrupter of the second load branch, a fourth line and the second mechanical switching element are arranged outside the defined area of the first vacuum interrupter of the second load branch.

According to at least one embodiment, at least the second vacuum interrupter of the second load branch, the third line, the fourth line and the mechanical switching elements are arranged outside the defined area of the second vacuum interrupter of the first load branch. According to at least one embodiment, at least the second vacuum interrupter of the first load branch, the third line, the fourth line and the mechanical switching elements are arranged outside the defined area of the second vacuum interrupter of the second load branch.

According to at least one embodiment, the first winding tap is electrically connected via a series connection of a first vacuum interrupter and a second vacuum interrupter via the first load branch to a load dissipation and the second winding tap is connected via a series connection of a first vacuum interrupter and a second vacuum interrupter via the second load branch electrically connected to the load transfer.

According to at least one embodiment, a transition resistor is arranged in each case parallel to the first vacuum interrupter of the first and the second load branch.

According to at least one embodiment, the transition resistors are arranged outside the defined area of the second vacuum interrupter of the first load branch and outside of the defined area of the second vacuum interrupter of the second load branch.

According to at least one embodiment, the first mechanical switching contact is arranged between the second vacuum interrupter of the first load branch and the load diverter and the second mechanical switching contact is arranged between the second vacuum interrupter of the second load branch and the load derivation device.

According to at least one embodiment, the mechanical switching contacts are arranged outside of the defined area of the vacuum interrupters.

According to at least one embodiment, the mechanical switching contacts are designed as isolating switches.

According to at least one embodiment, the first and the second vacuum interrupter are electrically connected to one another via the first electrical line and second vacuum interrupter and the first mechanical switching element via the third electrical line in the first load branch and the first and second vacuum interrupter are via the second load branch the second line and the second vacuum interrupter and the first mechanical switching element electrically connected to one another via the fourth line. According to at least one embodiment, the electrical lines are each connected in an electrically conductive manner to the vacuum interrupters via connecting elements.

According to at least one embodiment, the lines each have a first end and a second end, the first end being electrically connected via the connecting element to the movable contact of the vacuum interrupter and the second end being electrically connected via the connecting element to the fixed contact of the vacuum interrupter.

According to at least one embodiment, a permanent main contact is additionally provided parallel to each load branch, which takes over at least part of the continuous current flow in stationary operation and is in an electrically conductive connection directly with the load derivation.

According to at least one embodiment, the vacuum interrupters are arranged in a circle around a control shaft.

According to at least one embodiment, the first and the second mechanical switching contact are arranged in mirror image to an axis, the axis lying on the switching shaft.

According to at least one embodiment, two vacuum interrupters are arranged in mirror image to the axis.

In the following, the invention is explained in detail on the basis of exemplary embodiments with reference to the drawings. Components that are functionally identical or have an identical effect can be provided with identical reference symbols. Identical components or components with an identical function may only be explained with reference to the figure in which they first appear. The explanation is not necessarily repeated in the subsequent figures.

Show it

Figure 1 is a schematic representation of a step transformer with a

On-load tap-changer according to the improved concept;

FIG. 2 shows a schematic representation of the winding taps of a step transformer; FIG. 3 shows a schematic representation of an exemplary embodiment of an on-load tap-changer according to the improved concept;

FIGS. 4a to 4f show an exemplary switching sequence of the on-load tap-changer from FIG. 3;

FIG. 5 shows an exemplary embodiment of a diverter switch according to the improved concept;

FIG. 6 shows a further view of the exemplary embodiment from FIG. 5; FIG. 7 shows a further view of the exemplary embodiment from FIG. 5;

and

FIG. 8 shows a further view of the exemplary embodiment from FIG.

The figures merely represent exemplary embodiments of the invention, but without restricting the invention to the exemplary embodiments shown.

FIG. 1 shows a schematic representation of a step transformer 2 with a load step switch 1, which has a selector 3 and a diverter switch 4. The load step switch 1 is driven by a motor 22.

FIG. 2 shows schematically a regulating winding 25 of the step transformer 2 (see FIG. 1) with different winding taps Ni, Nj, N _n . The winding taps Ni, Nj, N _N are switched on and off by the on-load tap-changer 1. The disconnection or connection can be implemented by any means, such as a selector 3, a load switch 4, etc., are implemented. The on-load tap-changer 1 is actuated via the motor 22.

FIG. 3 shows a schematic illustration of an exemplary embodiment of an on-load tap-changer 1. According to the improved concept, the on-load tap-changer 1 comprises a selector 3 with at least a first fixed contact 23.1 and a second fixed contact 23.2, which can each be connected to a winding tap Ni, ..., Nj, ..., N _{N of} the step transformer 2 . The total number of fixed contacts depends on the number of winding taps Ni, ..., Nj, ..., N _N. Furthermore, the on-load tap changer 1 has a first movable selector contact 24.1 and a second movable selector contact 24.2, which can contact the individual fixed contacts 23.1, 23.2 of the rule 25 winding. The on-load tap changer 1 also includes a load switch 4, with a first load branch 5.1 and a second load branch 5.2. According to In this exemplary embodiment, the first load branch 5.1 connects the first fixed contact 23.1 via a series circuit of a first vacuum interrupter 6.1 and a second vacuum interrupter 6.2 with the load dissipation 8, and the second load branch 5.2 connects the second fixed contact 23.2 via a series circuit from a first vacuum interrupter 7.1 and a second vacuum interrupter 7.2 with the load dissipation 8. Parallel to the first vacuum interrupter 6.1 or 7.1, a transition resistor 9.1 or

9.2 switched. A first mechanical switching element 18.1 is arranged between the second vacuum interrupter 6.2 and the load dissipation 8, and a second mechanical switching element is located between the second vacuum interrupter 7.2 and the load dissipation 8

18.2 arranged. A first line 10.1 connects the first vacuum interrupter 6.1 and the second vacuum interrupter 6.2 to one another in an electrically conductive manner and a second line

10.2 electrically connects the first vacuum interrupter 7.1 and the second vacuum interrupter 7.2 to one another. Furthermore, a third line 10.3 connects the second vacuum interrupter 6.2 to the first mechanical switching element 18.1 and a fourth line 10.4 connects the second vacuum interrupter 7.2 to the second mechanical switching element 18.2. Parallel to each load branch 5.1, 5.2 there is also an additional permanent main contact 19.1,

19.2 arranged. Figure 2 shows the on-load tap-changer 1 in a stationary state in which at least part of the load current flows from the winding tap via the permanent main contact 19.1 via the first fixed contact 23.1 to the load dissipation 8, in particular a larger part than via the load branch 5.1.

In Figures 4a to 4e an exemplary switching sequence of the on-load tap-changer 1 ge according to the improved concept is described, with the second fixed contact 23.2 on the first fixed contact 23.1, or the corresponding winding taps Ni, ..., Nj, ..., N _{N of} the step transformer 2 is switched.

In a step a (see FIG. 4a), the permanent main contact 19.2 is closed or remains closed. The on-load tap-changer 1 is in the stationary state, in which at least part of the load current flows through the permanent main contact 19.2 from the corresponding winding tap N _{+ i} via the second fixed contact 23.2 to the load dissipation 8, in particular a larger part than through the load branch 5.2.

In a step b (see FIG. 4b) the permanent main contact 19.2 is opened and the first mechanical switching contact 18.1 is closed. The current now flows through the first vacuum switchover tube 7.1 of the second load branch 5.2, the second line 10.2, the second vacuum switchover tube 7.2 of the second load branch 5.2, the fourth line 10.4 and the second mechanical switching contact 18.2 for load dissipation 8. In a step c (see. Fig. 4c), the first vacuum interrupter 7.1 of the second load branch 5.2 is opened. During the opening process, the second vacuum interrupter 7.2, the fourth line 10.4 and the second mechanical switching contact 18.2 are current-carrying and spatially outside the defined area 14 (see, for example, FIGS. 6-8) of the vacuum interrupter 7.1. The current then flows from the fixed contact 23.2 via the transition resistor 9.2, the second vacuum interrupter 7.2, the fourth line 10.4 and the second mechanical switching contact 18.2 to the load dissipation 8.

In a step d (see. Fig. 4d) the second vacuum interrupter 6.2 of the first load two tot 5.1 is closed. The load current is now divided between the first load branch 5.1 and the second load branch 5.2. In addition, a circular current is superimposed.

In a step e (see. Fig. 4e) the second vacuum interrupter 7.2 of the second load branch 5.2 is opened. During the opening process, the second vacuum interrupter 6.2 of the first load branch 5.1, the first mechanical switching element 18.1 of the first load branch 5.1, the second mechanical switching element 18.2 of the second load branch 5.2 and the connecting lines 27 to the transition resistors 9.1 and 9.2 of the first load branch 5.1 and des second load branch 5.2 with current flowing through it and spatially outside the defined area 14 (see, for example, FIGS. 6-8) of vacuum interrupter 7.2 of second load branch 5.2. The current then flows from the fixed contact 23.1 via the transition resistor 9.1, the second vacuum interrupter 6.2 of the first load branch 5.1, the third line 10.3 and the first mechanical switching contact 18.1 to the load discharge device 8.

In a step f (cf. FIG. 4f), the first vacuum interrupter 6.1 of the first load branch 5.1 is closed. The current now flows through the first vacuum interrupter 6.1, the first line 10.1, the second vacuum interrupter 6.2, the third line 10.3 and the first mechanical switching contact 18.1 for load dissipation 8.

In a step g (see FIG. 3) the permanent main contact 19.1 in the first load branch 5.1 is closed and the second mechanical switching contact 18.2 in the second load branch 5.2 opens. The on-load tap-changer 1 is again in the stationary state, as shown and explained in FIG. 3.

Figures 5 and 6 each show an exemplary embodiment of a diverter switch 4 according to the improved concept, with the purpose of clarity of the load transfer Switch 4 is shown from two different side perspectives. The four vacuum interrupters 6.1, 6.2, 7.1, 7.2 are arranged in a circle around a control shaft 20 and each have a movable contact 11 and a fixed contact 12. The vacuum interrupters 6.1 and 6.2 are electrically connected to one another lei tend via the first electrical line 10.1 and the vacuum interrupters 7.1 and 7.2 via the second electrical line 10.2. The electrically conductive connection is implemented via connecting elements 17, which are designed, for example, as screws and / or braids. The first end of the first electrical line 10.1 is electrically connected via a connecting element 17 to the movable contact 11 of the vacuum interrupter 6.1 and the second end is electrically connected via a connecting element 17 to the fixed contact 12 of the vacuum interrupter 6.2. The first end of the second line 10.2 is electrically connected via a connec tion element 17 to the movable contact 11 of the vacuum interrupter 7.1 and the second end is electrically connected via a connecting element 17 to the fixed contact 12 of the vacuum interrupter 7.2. The movable contact 11 and the fixed contact 12 of each vacuum interrupter 6.1, 6.2, 7.1, 7.2 touch in the closed state of the vacuum interrupter in at least one point 13. Starting from the respective contact point 13, each vacuum interrupter defines 6.1, 6.2, 7.1, 7.2 each have a spherical area 14. For the sake of clarity, the contacts 1 1 and 12, the contact point 13 of which in FIGS. 4 and 5 are shown only on a few vacuum switching tubes and are provided with a reference number.

Figures 7 and 8 each show an exemplary embodiment of the diverter switch in plan view. The diverter switch 4 has a housing 29 in which the Vakuumschaltröh Ren 6.1, 6.2, 7.1 and 7.2 are arranged. The housing 29 is essentially cylindrically shaped and constructed from a GRP plastic. The vacuum interrupters 6.1 and 6.2 are arranged in the housing 29 as a mirror image of the vacuum interrupters 7.1 and 7.2. For example, the vacuum interrupter 7.2 is opposite the vacuum interrupter

6.1 arranged and the vacuum interrupter 7.1 opposite to the vacuum interrupter 6.2. This creates the greatest possible distance between the vacuum interrupters 6.1 and

7.1 as well as the vacuum interrupters 6.2 and 7.2 generated. Between the vacuum interrupters 6.1 and 6.2 of the first load branch 5.1, that is, as well as the vacuum interrupters 7.1 and

7.2 of the second load branch 5.2 is, also in mirror image of one another, a first mechanical switching contact 18.1 and a second mechanical switching contact 18.2 respectively angeord net. In Figure 7 it is shown that the second line 10.2 and the second vacuum interrupter 7.2 of the second load branch 5.2 are arranged outside the defined area 14 of the first vacuum switchover tube 7.1 of the second load branch 5.2. In Figure 8 is also shown that the second vacuum interrupter 6.2 of the first load branch 5.1 lies outside the defined area 14 of the second vacuum interrupter 7.2 of the second load branch 5.2.

REFERENCE MARK

1 on-load tap-changer

2 step transformer

3 voters

4 diverter switches

5.1 first load branch

5.2 second load branch

6.1 first vacuum interrupter of the first load branch

6.2 second vacuum interrupter of the first load branch

7.1 first vacuum interrupter of the second load branch

7.2 second vacuum interrupter of the second load branch 8 load dissipation

9.1, 9.2 transition resistors

10.1 first line

10.2 second line

1 1 moving contact

12 fixed contact

13 Center / point of contact

14 defined area

15.1, 15.2 first end

16.1, 16.2 second end

17 connecting element

18.1 first mechanical switching contact

18.2 second mechanical switching contact

19.1, 19.2 permanent main contacts

20 selector shaft

21 axis

22 engine

23.1. 23.2 Permanent contacts for voters

24.1. 24.2 movable selector contacts

25 Regular winding

27 connecting cable

29 housing

(Ni, ..., Nj, ..., N _n ) winding taps

Claims

PATENT CLAIMS

1. On-load tap-changer (1) for uninterrupted switching between winding taps (Ni, ... Nj, N _n ) of a step transformer (2), comprising:

a selector (3) for powerless preselection on a selected winding tap (Nj);

a diverter switch (4) for the actual load switching from the previous winding tap (Nj-i) to the preselected winding tap (Nj), where the diverter switch (4) has a first load branch (5.1) and a second load branch (5.2);

at least one vacuum interrupter (6.1, 6.2, 7.1, 7.2) in the first load branch (5.1) and in the second load branch (5.2), wherein

- Each vacuum interrupter (6.1, 6.2, 7.1, 7.2) has a movable contact

(1 1) and a fixed contact (12), and

- Each vacuum interrupter (6.1, 6.2, 7.1, 7.2) an open state (31) in which the movable contact (1 1) and the fixed contact (12) do not touch, and a closed state in which the movable contact (1 1) and the fixed contact (12) in at least one contact point (13) can touch, occupy,

characterized in that

a spherical area (14) from the contact point (13) of the fixed contact

(12) and the movable contact (1 1) of each vacuum interrupter (6.1, 6.2, 7.1, 7.2) is defined; and

- The vacuum interrupters (6.1, 6.2, 7.1, 7.2) of the diverter switch (4) are arranged in such a way that parts of the diverter switch (4) through which current flows are arranged outside the defined area (14).

2. On-load tap-changer according to claim 1, wherein

the spherical area (14) around the point of contact (13) has a radius of at least 80 mm and at most 200 mm.

3. On-load tap-changer according to claim 1, wherein

Current-carrying parts of the diverter switch (4) a first electrical Lei device (10.1) of the first load branch (5.1) or a second electrical line (10.2) of the second load branch (5.2) or electrically conductive connecting elements (17) or a first mechanical switching contact (18.1) or a second mechanical switching contact (18.2) that are outside the spherical area (14) of each vacuum interrupter (6.1, 6.2, 7.1, 7.2) are arranged.

4. On-load tap-changer according to one of the preceding claims 1 -3, wherein

- The second load branch (5.2) of the diverter switch (4) comprises a first vacuum interrupter (7.1) and a second vacuum interrupter (7.2),

at least the second line (10.2), the second vacuum interrupter (7.2) of the second load branch (5.2) and a fourth line (10.4) outside the defi ned area (14) of the first vacuum interrupter (7.1) of the second load branch (5.2) are arranged .

5. On-load tap-changer according to one of the preceding claims 1 -3, wherein

- The first load branch (5.1) of the diverter switch (4) comprises a first vacuum interrupter (6.1) and a second vacuum interrupter (6.2),

- At least the second vacuum interrupter (6.2) of the first load branch (5.1), a third line (10.3) and the fourth line (10.4) outside the defined area (14) of the second vacuum interrupter (7.2) of the second load branch

(5.2) are arranged.

6. On-load tap-changer according to one of the preceding claims 4 or 5, wherein

- the first load branch (5.1) electrically connects a winding tap (Nj) via a series connection of the first vacuum interrupter (6.1) and the second vacuum interrupter (6.2) of the first load branch (5.1) to a load diverter (8),

- The second load branch (5.2) each electrically connects a winding tap (N _{+ i} ) via a series connection of the first vacuum interrupter (7.1) and the second vacuum interrupter (7.2) of the second load branch (5.2) with the load dissipation (8).

7. On-load tap-changer according to claim 3, wherein

- The first mechanical switching contact (18.1) is arranged between the second vacuum interrupter (6.2) of the first load branch (5.1) and the load diverter (8); and between the second vacuum interrupter (7.2) of the second load branch (5.2) and the load dissipation (8), the second mechanical switching contact (18.2) is angeord net.

8. On-load tap-changer according to claim 7, wherein

- The mechanical switching contacts (18.1, 18.2) are designed as disconnectors.

9. On-load tap-changer according to one of the preceding claims, wherein

- in the first load branch (5.1) the first vacuum interrupter (6.1) and the second vacuum interrupter (6.2) via the first electrical line (10.1) and the second vacuum interrupter (6.2) and the first mechanical switching contact (18.1) via the third electrical line ( 10.3) are electrically connected to each other, in the second load branch (5.2) the first vacuum interrupter (7.1) and the second vacuum interrupter (7.2) via the second electrical line (10.2) and the second vacuum interrupter (7.2) and the first mechanical switching contact (18.2) are electrically connected to one another via the fourth electrical line (10.4).

10. On-load tap-changer according to claim 9, wherein

the electrical lines (10.1, 10.2, 10.3, 10.4) are each connected to the vacuum interrupters (6.1, 6.2, 7.1, 7.2) in an electrically conductive manner via connecting elements (17).

1 1. On-load tap-changer according to one of the preceding claims, wherein

- A permanent main contact (19.1, 19.2) is also provided parallel to each load branch (5.1, 5.2), which in stationary operation takes over at least part of the continuous current flow and is directly in electrically conductive connection with the load dissipation (8).

12. On-load tap-changer according to one of the preceding claims, wherein

the vacuum interrupters (6.1, 6.2, 7.1, 7.2) are arranged in a circle around a control shaft (20).

13. On-load tap-changer according to one of the preceding claims, wherein

- The first and the second mechanical switching contact (18.1, 18.2) are arranged as a mirror image of an axis (21) of the switching shaft (20).