Tap-changer switching system and method of operating same

Abstract

The invention relates to a switching system for a tapped transformer with on-load tap changer wherein the tapped transformer comprises a main winding with a first main terminal; a coarse winding with a first coarse terminal and with a second coarse terminal; a control winding with a first control terminal; and an on-load tap changer that has a switch terminal and that interacts with the control winding;
the switching system comprising a lead; a first switch subassembly comprising a first main fixed contact that can be connected to the first main terminal; a first coarse fixed contact that can be connected to the first coarse terminal; a first control fixed contact that can be connected to the first control terminal; a first switch fixed contact that can be connected to the first switch terminal; and a first movable bridge contact that is formed such that it electrically bridges or connects at least two fixed contacts of its switch subassembly in each stationary operating position of the switching system and/or during each switch over process of the switching system; a second switch subassembly comprising a second coarse fixed contact that can be connected to the second coarse terminal; a second control fixed contact that can be connected to the first control terminal and/or that is connected to the first control fixed contact; a second switch fixed contact that can be connected to the switch terminal and/or that is connected to the first switch fixed contact; and a second movable bridge contact that is formed such that it electrically bridges at least two fixed contacts of its switch subassembly in each stationary operating position of the switching system and/or during each switch-over process of the switching system; and a third switch subassembly comprising a first lead fixed contact that is connected to the lead; a third coarse fixed contact that can be connected to the first coarse terminal and/or that is connected to the first coarse fixed contact; a third control fixed contact that can be connected to the first control terminal and/or that is connected to the first control fixed contact; a third switch fixed contact that can be connected to the switch terminal and/or that is connected to the first switch fixed contact; and
a third movable bridge contact that is formed such that it electrically bridges at least two fixed contacts of its switch subassembly in each stationary operating position of the switching system and/or during each switch over process of the switching system.

Claims

1. A switching system for a tapped transformer comprising a main winding with a first main terminal; a coarse winding with a first coarse terminal and with a second coarse terminal; a control winding with a first control terminal; and an on-load tap changer that has a switch terminal and that interacts with the control winding; the switching system comprising a lead; a first switch subassembly comprising a first main fixed contact that can be connected to the first main terminal; a first coarse fixed contact that can be connected to the first coarse terminal; a first control fixed contact that can be connected to the first control terminal; a first switch fixed contact that can be connected to the first switch terminal; and a first movable bridge contact that is formed such that it electrically bridges at least two fixed contacts of its switch subassembly in each stationary operating position of the switching system and/or during each switch over process of the switching system; a second switch subassembly comprising a second coarse fixed contact that can be connected to the second coarse terminal; a second control fixed contact that can be connected to the first control terminal and/or that is connected to the first control fixed contact; a second switch fixed contact that can be connected to the switch terminal and/or that is connected to the first switch fixed contact; and a second movable bridge contact that is formed such that it electrically bridges at least two fixed contacts of its switch subassembly in each stationary operating position of the switching system and/or during each switch over process of the switching assembly; and a third switch subassembly comprising a first lead fixed contact that is connected to the lead; a third coarse fixed contact that can be connected to the first coarse terminal and/or that is connected to the first coarse fixed contact; a third control fixed contact that can be connected to the first control terminal and/or that is connected to the first control fixed contact; a third switch fixed contact that can be connected to the switch terminal and/or that is connected to the first switch fixed contact; and a third movable bridge contact that is formed such that it electrically bridges at least two fixed contacts of its switch subassembly in each stationary operating position of the switching assembly and/or during each switch over process of the switching system.

2. The switching system according to claim 1, further comprising a drive shaft, at which the bridge contacts are nonrotatably arranged.

3. The switching system according to claim 2, wherein the drive shaft is coupled to an actuator.

4. The switching system according to claim 3 wherein the actuator comprises a motor drive and/or a direct drive and/or a manual drive and/or a spring energy storage device.

5. The switching system according to claim 1, wherein the first switch subassembly comprises a second and a third main fixed contact that can each be connected to the first main terminal and/or that are connected to the first main fixed contact; and a fourth coarse fixed contact that can be connected to the first coarse terminal and/or that is connected to the first coarse fixed contact the first main fixed contact is arranged between the first switch fixed contact and the first control fixed contact; the third main fixed contact is arranged between the first control fixed contact and the fourth coarse fixed contact; and the second main fixed contact is arranged between the fourth coarse fixed contact and the first coarse fixed contact.

6. The switching system according to claim 1, wherein the second switch subassembly comprises a fifth and a sixth coarse fixed contact that can each be connected to the second coarse terminal and/or that are connected to the second coarse fixed contact; a fourth control fixed contact that can be connected to the first control terminal and/or that is connected to the first control fixed contact; and a fourth switch fixed contact that can be connected to the switch terminal and/or that is connected to the first switch fixed contact; the second coarse fixed contact is arranged between the second control fixed contact and the fourth switch fixed contact; the sixth coarse fixed contact is arranged between the fourth switch fixed contact and the second switch fixed contact; and the fifth coarse fixed contact is arranged between the second switch fixed contact and the fourth control fixed contact.

7. The switching system according to claim 1, wherein the third switch subassembly comprises a second and a third lead fixed contact that are each connected to the lead and/or to the first lead fixed contact; and a seventh coarse fixed contact that can be connected to the first coarse terminal and/or that is connected to the first coarse fixed contact; the first lead fixed contact is arranged between the third coarse fixed contact and the seventh coarse fixed contact; the third lead fixed contact is arranged between the seventh coarse fixed contact and the third control fixed contact; and the second lead fixed contact is arranged between the third control fixed contact and the third switch fixed contact.

8. The switching system according to claim 1, wherein the fixed contacts in each switch subassembly are arranged rotationally symmetrically and/or on a circular orbit around the drive shaft.

9. The switching system according to claim 1, wherein the individual switch subassemblies are electrically insulated from each other.

10. The switching system according to claim 1, wherein the switch subassemblies are arranged in different horizontal planes.

11. A switching system for a tapped transformer comprising a main winding with a first main terminal; a coarse winding with a first coarse terminal and with a second coarse terminal; a control winding with a first control terminal; and an on-load tap changer that has a switch terminal and that interacts with the control winding; the switching system comprising a lead, wherein the switching system that is in particular designed according to claim 1, is designed such that it can assume a first stationary operating position, in which it switches the coarse winding antiserially and the control winding antiserially to the main winding; it can assume a second stationary operating position, in which it switches the coarse winding antiserially and the control winding serially to the main winding; it can assume a third stationary operating position, in which it switches the coarse winding serially and the control winding antiserially to the main winding; and that it can assume a fourth stationary operating position, in which it switches the coarse winding serially and the control winding serially to the main winding.

12. The switching system according to claim 1, comprising several fixed contacts, at least one of which can in each case be connected to the first main terminal, the first coarse terminal, the first control terminal, the switch terminal, the second coarse terminal, the first control terminal, and the switch terminal and at least one other one of which is connected to the lead; and three movable bridge contacts that each electrically bridge at least two fixed contacts.

13. The switching system according to claim 1, which switching assembly is designed such that it can switch over from the first operating position to the second operating position, from the second operating position to the first and the third operating position, from the third operating position to the second and the fourth operating position, and from the fourth operating position to the third operating position; and/or that it cannot switch over from the first operating position to the fourth operating position, nor from the fourth operating position to the first operating position.

14. The switching system according to claim 1 that is designed such that it switches a current path through the control winding; and/or that it switches the first control terminal and the switch terminal or the control winding to the main terminal and the lead or to the main winding and/or the coarse winding in each operating position and/or during each switch over process.

15. The switching system according to claim 1, wherein the main winding, the coarse winding, and the control winding are galvanically separated from one another.

16. A tapped transformer, comprising a main winding with a first main terminal; a coarse winding with a first coarse terminal and with a second coarse terminal; a control winding with a first control terminal and an on-load tap changer that has a switch terminal and that interacts with the control winding; and a switching system according to claim 1.

17. The tapped transformer according to claim 16, wherein the first main fixed contact is connected to the first main terminal; the first coarse fixed contact is connected to the first coarse terminal; the first control fixed contact is connected to the first control terminal; the first switch fixed contact is connected to the first switch terminal t; the second coarse fixed contact is connected to the second coarse terminal; the second control fixed contact is connected to the first control terminal and/or to the first control fixed contact; the second switch fixed contact is connected to the switch terminal and/or to the first switch fixed contact; the first lead fixed contact is connected to the lead; the third coarse fixed contact is connected to the first coarse terminal and/or to the first coarse fixed contact; the third control fixed contact is connected to the first control terminal and/or to the first control fixed contact; and the third switch fixed contact is connected to the switch terminal and/or to the first switch fixed contact.

18. The tapped transformer according to claim 1, wherein the main winding, the coarse winding, and the control winding are galvanically separated from one another.

19. A method of operating a switching system that is in particular designed according to claim 1, wherein the switching system is operated in four stationary operating positions such that the coarse winding and/or the control winding of the main winding is additively and/or subtractively connected, as the case may be, in dependence on the corresponding operating position.

20. A method of operating an electrical system comprising a main winding with a first main terminal; a coarse winding with a first coarse terminal and with a second coarse terminal; a control winding; an on-load tap changer that has a switch terminal and that interacts with the control winding; a lead; and, a switching system according to claim 1; wherein the method according to the previous claim 18; the coarse winding is switched antiserially and the control winding is switched antiserially to the main winding in a first stationary operating position; the coarse winding is switched antiserially and the control winding is switched serially to the main winding in a second stationary operating position; the coarse winding is switched serially and the control winding is switched antiserially to the main winding in a third stationary operating position; and the coarse winding is switched serially and the control winding is switched serially to the main winding in a fourth stationary operating position.

21. The method according to claim 20, wherein, in the first stationary operating position, the first main terminal is electrically connected to the first main fixed contact; the first bridge contact electrically bridges the first main fixed contact and the first switch fixed contact; and the first switch fixed contact is electrically connected to the switch terminal; the second coarse fixed contact is electrically connected to the second coarse terminal; the second bridge contact electrically bridges the second coarse fixed contact and the second control fixed contact; and the second control fixed contact is electrically connected to the first control terminal; and the third coarse fixed contact is electrically connected to the first coarse terminal; the third bridge contact electrically bridges the first lead fixed contact and the third coarse fixed contact; and the first lead fixed contact is electrically connected to the lead.

22. The method according to claim 20, wherein, in the second stationary operating position, the first main terminal is electrically connected to the first main fixed contact and to the third main fixed contact; the first bridge contact electrically bridges the first main fixed contact, the third main fixed contact, and the first control fixed contact; and the first control fixed contact is electrically connected to the first control terminal; the second coarse fixed contact and the sixth coarse fixed contact are electrically connected to the second coarse terminal; the second bridge contact electrically bridges the second coarse fixed contact, the sixth coarse fixed contact, and the fourth switch fixed contact; and the fourth switch fixed contact is electrically connected to the switch terminal; and the first lead fixed contact and the third lead fixed contact are connected to the lead; the third bridge contact electrically bridges the first lead fixed contact, the third lead fixed contact and the seventh coarse fixed contact; and the seventh coarse fixed contact is electrically connected to the first coarse terminal.

23. The method according to claim 20, wherein, in the third stationary operating position, the first main terminal is electrically connected to the third main fixed contact and to the second main fixed contact; the first bridge contact electrically bridges the third main fixed contact, the second main fixed contact, and the fourth coarse fixed contact; and the fourth coarse fixed contact is electrically connected to the first coarse terminal; the fifth coarse fixed contact and the sixth coarse fixed contact are electrically connected to the second coarse terminal; the second bridge contact electrically bridges the fifth coarse fixed contact, the sixth coarse fixed contact, and the second switch fixed contact; and the second switch fixed contact is electrically connected to the switch terminal; and the second lead fixed contact and the third lead fixed contact is connected to the lead; the third bridge contact electrically bridges the second lead fixed contact, the third lead fixed contact, and the third control fixed contact; and the third control fixed contact is electrically connected to the first control terminal.

24. The method of operating a switching system according to claim 20, wherein, in the fourth stationary operating position, the first main terminal is electrically connected to the second main fixed contact; the first bridge contact electrically bridges the second main fixed contact and the first coarse fixed contact; and the first coarse fixed contact is electrically connected to the first coarse terminal; the fifth coarse fixed contact is electrically connected to the second coarse terminal; the second bridge contact electrically bridges the fifth coarse fixed contact and the fourth control fixed contact; and the fourth control fixed contact is electrically connected to the first control terminal; and the third switch fixed contact is electrically connected to the switch terminal; the third bridge contact electrically bridges the third switch fixed contact and the second lead fixed contact; and the second lead fixed contact is electrically connected to the lead.

Description

(1) In the following, embodiments of the invention are exemplarily explained in detail by means of the attached drawings. The individual features thereof are, however, not limited to the individual embodiments but can be connected and/or combined with individual features described further above and/or with individual features of other embodiments. Each example in the illustrations is provided by way of explanation, not limitation of the invention. The reference characters included in the claims are by no means intended to limit the scope of protection of the invention, but rather merely refer to the embodiments shown in the figures, in which

(2) FIG. 1 shows a switching system according to the invention in a first stationary operating position;

(3) FIG. 2 shows a switching system according to the invention in a second stationary operating position;

(4) FIG. 3 shows a switching system according to the invention in a third stationary operating position; and

(5) FIG. 4 shows a switching system according to the invention in a fourth stationary operating position.

(6) Shown in FIG. 1 is a switching system according to the invention with a stylized, only partly illustrated tapped transformer and with an on-load tap changer 8 in a first stationary operating position. In this context, FIG. 1 does not show the entire tapped transformer, but rather only those parts of the winding of the tapped transformer that correspond to the switching system according to the invention, where the winding here can be the primary side or the secondary side. The tapped transformer has a main winding 5 with a first main terminal 0 and with a second main terminal N, which second main terminal N can be connected to a power line that is associated with a phase of an alternating current network, or to a star point or to a vertex of a delta connection. Also provided is a lead A that can be connected to chassis ground or to earth or to a star point or to a vertex of a delta connection. The tapped transformer furthermore provides a coarse winding 6 with a first coarse terminal 1 and with a second coarse terminal 2; and a control winding 7 with a first control terminal 3, with a second control terminal 4, and with a plurality of winding taps 7.1 . . . 7.7; as well as an on-load tap changer 8 arranged between the control winding 7 and a switch terminal L. The on-load tap changer 8 can be an on-load tap changer as known for many decades from the prior art. In this context, the winding tap 7.1 has the same potential as the first control terminal 3, while the winding tap 7.7 has the same potential as the second control terminal 4. The on-load tap changer 8 in turn comprises an also already known load diverter switch 8.1 as well as a selector 9 that performs a powerless preselection of the winding taps 7.1 . . . 7.7 of the control winding 7 with its selector arms 9.1 and 9.2 prior to the load diverter switch 8.1 performing the actual uninterrupted switch over under load. The on-load tap changer 8 can alternatively also be an integrated on-load tap changer 8 as is known from the prior art. No matter whether the on-load tap changer 8 with its selector 9 is formed as a separate unit as load diverter switch 8.1 or whether it is integrated, it is formed such that it can move to the entire control range of the control winding 7, that is, to all winding taps 7.1 . . . 7.7 present, and is electrically contactable to these.

(7) In this context, the switching system provides a first switch subassembly 10 and a second switch subassembly 20 as well as a third switch subassembly 30. Each switch subassembly 10, 20, and 30 for its part in turn comprises several fixed contacts 0.11, 0.12, 1.11 . . . 1.13, 1.31, 1.32, 2.21 . . . 2.23, 3.1, 3.21, 3.22, 3.3, L.1, L.21, L.22, L.3, A.31 . . . A.33, where each of the switch subassemblies 10, 20, and 30 in each case has a movable bridge contact 11, 21, and 31 that is formed to be electrically bridging, and that is in each case dimensioned such that said bridge contact 11, 21, and 31 bridges at least two fixed contacts of each switch subassembly 10, 20, and 30 simultaneously during each switch over process of the switching system. During each stationary operating position, each movable bridge contact 11, 21, 31 is essentially also electrically in an operative connection with at least two fixed contacts 0.11, 0.12, 1.11 . . . 1.13, 1.31, 1.32, 2.21 . . . 2.23, 3.1, 3.21, 3.22, 3.3, L.1, L.21, L.22, L.3, A.31 . . . A.33 of each switch subassembly 10, 20, and 30. For this purpose, the respective movable bridge contact 11, 21, and 31 of each switch subassembly 10, 20, and 30 is nonrotatably connected with a drive shaft 40 that is provided collectively for all switch subassemblies 10, 20, and 30.

(8) The first switch subassembly 10 in this context comprises, in particular, the first, second, and third main fixed contact 0.11, 0.12, and 0.13, the first coarse fixed contact 1.11, the fourth coarse fixed contact 1.12, the first control fixed contact 3.1, and the first switch fixed contact L.1 that are electrically contactable with the associated terminals 0, 1, 3 and L such that, for example, the first, second, and third main fixed contact 0.11, 0.12, 0.13 correspond with first main terminal 0, the first and the fourth coarse fixed contact 1.11, 1.12 correspond with the first coarse terminal 1, the first control fixed contact 3.1 corresponds with the first control terminal 3, and the switch fixed contact L.1 corresponds with the switch terminal L according to the stationary operating position. The reference characters of the fixed contacts in the present patent application are here selected such that the digit in front of the point indicates the respectively corresponding terminal, with which the respective fixed contact electrically corresponds, the first digit after the point stands for the respective switch subassembly 10, 20, or 30, as the case may be, which the fixed contact is associated to, and the last digit of the corresponding switch subassembly numbers the fixed contacts consecutively in clockwise order. The nomenclature of the reference characters applies in consecutive order to all fixed contacts of the switch subassemblies 10, 20, and 30. If, for example, two fixed contacts of different switch subassemblies are electrically in contact with one and the same terminal during a switch over process, that is, in a middle position that is only temporarily taken, then the fixed contacts of the different switch subassemblies are also electrically connected among each other.

(9) The second switch subassembly 20 in this context comprises, in particular, the second coarse fixed contact 2.21, the fifth coarse fixed contact 2.22, the sixth coarse fixed contact 2.23, the second control fixed contact 3.21, the fourth control fixed contact 3.22, the second switch fixed contact L.21, and the fourth switch fixed contact L.22 that are electrically contactable with the associated terminals 2, 3, and L, that is, for example, the second coarse fixed contact 2.21, the fifth coarse fixed contact 2.22, and the sixth coarse fixed contact 2.23 are contactable with the second coarse terminal 2, the second control fixed contact 3.21 and the fourth control fixed contact 3.22 are contactable with the first control terminal 3, and the second switch fixed contact L.21 and the fourth switch fixed contact L.22 are contactable with the switch terminal L according to the stationary operating position.

(10) The third switch subassembly 30 in this context comprises, in particular, the first lead fixed contact A.31, the second lead fixed contact A.32, the third lead fixed contact A.33, the third coarse fixed contact 1.31, the seventh coarse fixed contact 1.32, the third control fixed contact 3.3, and the third switch fixed contact L.3 that are electrically contactable with the associated terminals 1, 3, L, and A, that is, for example, the third coarse fixed contact 1.31 and the seventh coarse fixed contact 1.32, are contactable with the first coarse terminal 1, the third control fixed contact 3.3 is contactable with the first control terminal 3, and the first lead fixed contact A.31, the second lead fixed contact A.32, and the third lead fixed contact A.33 are contactable with the lead A according to the stationary operating position.

(11) Each switch subassembly 10, 20, and 30 moreover has a further vacant contact 12, 22, or 32, as the case may be, that corresponds with no further terminal or no further fixed contacts of the other switch subassemblies. From a circuit-technical point of view, it would also be conceivable to dispense with these vacant contacts 12, 22, or 32, as the case may be, of the switch subassemblies 10, 20, and 30.

(12) Shown in FIG. 1 is the first of four possible stationary operating positions. The selector arms 9.1 and 9.2 or, as the case may be, the on-load tap changer 8, can run through the entire control range of the control winding 7 in both directions in each stationary operating position. In a first stationary operating position, the load current IL takes the path from the second main terminal N through the main winding 5, up to the first main terminal 0, to the first main fixed contact 0.11 of the first switch subassembly 10, from there via the first bridge contact 11 up to the switch fixed contact L.1, from there to the switch terminal L via the on-load tap changer 8 and via the selector 9 to the second control terminal 4; and subsequently the load current IL runs through the entire control winding 7 up to the first control terminal 3. From there, the load current IL flows on to the second coarse fixed contact 2.21 of the second switch subassembly 20, then via the second bridge contact 21 to the fourth switch fixed contact L.22, from there to the second coarse terminal 2, through the entire coarse winding 6 up to the first coarse terminal 1, and finally from there, via the third coarse fixed contact 1.31 of the third switch subassembly 30 and via the third bridge contact 31 to the first lead fixed contact A.31, to the lead A.

(13) For this purpose, the first main terminal 0 is electrically connected to the first main fixed contact 0.11 in the first stationary operating position, the first bridge contact 11 electrically bridges the first main fixed contact 0.11 and the first switch fixed contact L.1, and the first switch fixed contact L.1 is electrically connected to the switch terminal L. Furthermore, the second coarse fixed contact 2.21 is electrically connected to the second coarse terminal 2; the second bridge contact 21 electrically bridges the second coarse fixed contact 2.21 and the second control fixed contact 3.21; and the second control fixed contact 3.21 is electrically connected to the first control terminal 3. Finally, the third coarse fixed contact 1.31 is electrically connected to the first coarse terminal 1; the third bridge contact 31 electrically bridges the first lead fixed contact A.31 and the third coarse fixed contact 1.31; and the first lead fixed contact A.31 is electrically connected to the lead A. In this first stationary operating position, a mechanical switch can moreover be provided between the first coarse terminal 1 and the first coarse fixed contact 1.11 as well as the fourth coarse fixed contact 1.12, which mechanical switch can be open in this stationary operating position.

(14) Initiating a rotation of the drive shaft 40 can here be carried out by an actuator 41 provided collectively for all switch subassemblies 10, 20, and 30. The actuator 41 can then comprise a motor drive and/or a direct drive and/or a manual drive and/or a spring energy storage device, for example. If it is intended to carry out a switch over from a first into a second stationary operating position by the switching system according to the invention, it is necessary to move to the beginning of and to switch the control winding 7, that is the winding tap 7.1 provided at the first control terminal 3, by the selector arm 9.1 or 9.2 for this purpose.

(15) Shown in FIG. 2 is the second stationary operating position of the switching system according to the invention. For this purpose, the first, second, and third bridge contacts 11, 21, and 31 were stepped counter-clockwise, in each case by two fixed contact positions in relation to FIG. 1, by the drive shaft 40. During the entire switch over process, which is not illustrated here, at least two fixed contacts of each switch subassembly 10, 20, and 30 were in this context constantly electrically connected by the correspondingly movable bridge contacts 11, 21, and 31, and thus each part of the main winding 5, of the coarse winding 6, and of the control winding 7 were galvanically linked. Illustrated exemplarily by the first switch subassembly 10, this means that the first bridge contact 11 moved toward the first control fixed contact 3.1 adjacent to the first main fixed contact 0.11, where only the first main fixed contact 0.11 and the first switch fixed contact L.1 were temporarily switched electrically bridging by the first bridge contact 11, before the first bridge contact 11 then moved onto the first control fixed contact 3.1 and brushed over it during the further switch over process such that the first control fixed contact 3.1, the first main fixed contact 0.11, and the first switch fixed contact L.1 were electrically bridged at this point of time in the switch over, before the movable first bridge contact 11 took up its next stationary operating position of FIG. 2, in which the first main fixed contact 0.11, the first control fixed contact 3.1, and the third main fixed contact 0.13 are eventually electrically bridged. The above-described also applies functionally analogously to the switch over process of the switch subassemblies 20 and 30.

(16) In the second stationary operating position, the selector arms 9.1 and 9.2 or, as the case may be, the on-load tap changer 8, can also run through the entire control range of the control winding 7 in both directions such that the entire control winding 7, or also only parts of the control winding 7, can be connected or disconnected, as the case may be. In this stationary operating position, the load current IL takes the path from the second main terminal N through the main winding 5, up to the first main terminal 0, to the first main fixed contact 0.11 and to the third main fixed contact 0.13 of the first switch subassembly 10, from there via the movable first bridge contact 11 up to the first control fixed contact 3.1, from there to the first control terminal 3 via the selector 9 and via the on-load tap changer 8 to the switch terminal L. From there, the load current IL flows on to the fourth switch fixed contact L.22 of the second switch subassembly 20, then via the second bridge contact 21 to the second coarse fixed contact 2.21 and to the sixth coarse fixed contact 2.23, from there to the second coarse terminal 2, through the entire coarse winding 6 toward the first coarse terminal 1, and finally from there, via the seventh coarse fixed contact 1.32 of the third switch subassembly 30 and via the movable third bridge contact 31 to the first lead fixed contact A.31 and to the third lead fixed contact A.33, to the lead A.

(17) For this purpose, the first main terminal 0 is electrically connected to the first main fixed contact 0.11 and to the third main fixed contact 0.13 in the second stationary operating position; the first bridge contact 11 electrically bridges the first main fixed contact 0.11, the third main fixed contact 0.13 and the first control fixed contact 3.1; and the first control fixed contact 3.1 is electrically connected to the first control terminal 3. Furthermore, the second coarse fixed contact 2.21 and the sixth coarse fixed contact 2.23 are electrically connected to the second coarse terminal 2; the second bridge contact 21 electrically bridges the second coarse fixed contact 2.21, the sixth coarse fixed contact 2.23, and the fourth switch fixed contact L.22; and the fourth switch fixed contact L.22 is electrically connected to the switch terminal L. Finally, the first lead fixed contact A.31 and the third lead fixed contact A.33 are connected to the lead A; the third bridge contact 31 electrically bridges the first lead fixed contact A.31, the third lead fixed contact A.33 and the seventh coarse fixed contact 1.32; and the seventh coarse fixed contact 1.32 is electrically connected to the first coarse terminal 1.

(18) Shown in FIG. 3 is the third stationary operating position of the switching system according to the invention. For this purpose, the first, second, and third bridge contacts 11, 21, and 31 were stepped counter-clockwise, in each case by two fixed contact positions in relation to FIG. 2, by means of the drive shaft 40. During the entire switch over process, which is not illustrated here, again at least two fixed contacts of each switch subassembly 10, 20, and 30 were in this context constantly electrically connected by the corresponding bridge contacts 11, 21, and 31, and thus each part of the main winding 5, of the coarse winding 6, and of the control winding 7 were galvanically linked.

(19) In the third stationary operating position, the selector arms 9.1 and 9.2 or, as the case may be, the on-load tap changer 8, can also run through the entire control range of the control winding 7 in both directions such that the entire control winding 7, or also only parts of the control winding 7, can be connected or disconnected, as the case may be. In this stationary operating position, the load current IL takes the path from the second main terminal N through the main winding 5, up to the first main terminal 0, to the third main fixed contact 0.13 and to the third main fixed contact 0.12 of the first switch subassembly 10, from there via the movable first bridge contact 11 up to the fourth coarse fixed contact 1.12, from there to the first coarse terminal 1 through the entire coarse winding 6 toward the second coarse terminal 2. Subsequently, the load current IL flows on to the sixth coarse fixed contact 2.23 and to the fifth coarse fixed contact 2.22 of the second switch subassembly 20, continues via the bridging, movable second bridge contact 21 to the second switch fixed contact L.21, from there to the switch terminal L via the load diverter switch 8 and via the selector 9 to the second control terminal 4. From here, the load current IL finally flows on, through the control winding 7, up to the first control terminal 3 to the third control fixed contact 3.3 of the third switch subassembly 30 and to the movable third bridge contact 31 to the second and third lead fixed contact A.32 and A.33, to the lead A.

(20) For this purpose, the first main terminal 0 is electrically connected to the third main fixed contact 0.13 and to the second main fixed contact 0.12 in the third stationary operating position; the first bridge contact 11 electrically bridges the third main fixed contact 0.13, the second main fixed contact 0.12, and the fourth coarse fixed contact 1.12; and the fourth coarse fixed contact 1.12 is electrically connected to the first coarse terminal 1. Furthermore, the fifth coarse fixed contact 2.22 and the sixth coarse fixed contact 2.23 are electrically connected to the second coarse terminal 2; the second bridge contact 21 electrically bridges the fifth coarse fixed contact 2.22, the sixth coarse fixed contact 2.23, and the second switch fixed contact L.21; and the second switch fixed contact L.21 is electrically connected to the switch terminal L. Finally, the second lead fixed contact A.32 and the third lead fixed contact A.33 are electrically connected to the lead A; the third bridge contact 31 electrically bridges the second lead fixed contact A.32, the third lead fixed contact A.33 and the third control fixed contact 3.3; and the third control fixed contact 3.3 is electrically connected to the first control terminal 3.

(21) Shown in FIG. 4 is the fourth stationary operating position of the switching system according to the invention. For this purpose, the first, second, and third bridge contacts 11, 21, and 31 were stepped counter-clockwise, in each case by two fixed contact positions in relation to FIG. 3, by the drive shaft 40. During the entire switch over process, which is not illustrated here, again at least two fixed contacts of each switch subassembly 10, 20, and 30 were in this context constantly electrically connected by the correspondingly movable bridge contacts 11, 21, and 31, and thus each part of the main winding 5, of the coarse winding 6, and of the control winding 7 were galvanically linked.

(22) In the fourth stationary operating position, the selector arms 9.1 and 9.2 or, as the case may be, the on-load tap changer 8, can also run through the entire control range of the control winding 7 in both directions such that the entire control winding 7, or also only parts of the control winding 7, can be connected or disconnected, as the case may be. In this stationary operating position, the load current IL takes the path from the second main terminal N through the main winding 5, up to the first main terminal 0, to the second main fixed contact 0.12 of the first switch subassembly 10, from there via the movable first bridge contact 11 up to the first coarse fixed contact 1.11, from there to the first coarse terminal 1 through the coarse winding 6 toward the second coarse terminal 2. From there, the load current IL flows on to the fifth coarse fixed contact 2.22 of the second switch subassembly 20, then via the second bridge contact 21 to the fourth control fixed contact 3.22, and from there to the first control terminal 3 into the control winding 7. The load current IL subsequently takes the path via the selector 9 and via the load diverter switch 8.1 up to the switch terminal L, and finally from there, via the third switch fixed contact L.3 of the third switch subassembly 30 and via the third bridge contact 31 to the second lead fixed contact A.32, to the lead A.

(23) For this purpose, the first main terminal 0 is electrically connected to the second main fixed contact 0.12 in the fourth stationary operating position; the first bridge contact 11 electrically bridges the second main fixed contact 0.12 and the first coarse fixed contact 1.11; and the first coarse fixed contact 1.11 is electrically connected to the first coarse terminal 1. Furthermore, the fifth coarse fixed contact 2.22 is electrically connected to the second coarse terminal 2; the second bridge contact 21 electrically bridges the fifth coarse fixed contact 2.22 and the fourth control fixed contact 3.22; and the fourth control fixed contact 3.22 is electrically connected to the first control terminal 3. Finally, the third switch fixed contact L.3 is electrically connected to the switch terminal L; the third bridge contact 31 electrically bridges the third switch fixed contact L.3 and the second lead fixed contact A.32; and the second lead fixed contact A.32 is electrically connected to the lead A. In this fourth stationary operating position, a mechanical switch can moreover be provided between the first switch fixed contact L.1 of the first switching system 10 and the third switch fixed contact L.3 of the third switching system 30, as well as between the first coarse terminal 1 and the third and seventh coarse fixed contact 1.31 and 1.32 of the third switching system 30, which mechanical switch can be open in this stationary operating position.

REFERENCE CHARACTERS

(24) TABLE-US-00001 0 First main terminal 0.11 . . . 0.13 Main fixed contacts 1 First coarse terminal 1.11, 1.12 Coarse fixed contacts 1.31, 1.32 Coarse fixed contacts 2 Second coarse terminal 2.21 . . . 2.23 Coarse fixed contacts 3 First control terminal 3.1 Control fixed contact 3.21 . . . 3.22 Control fixed contacts 3.3 Control fixed contact 4 Second control terminal 5 Main winding 6 Coarse winding 7 Control winding 7.1 . . . 7.7 Winding taps 8 On-load tap changer 8.1 Load diverter switch 9 Selector 9.1 . . . 9.2 Selector arms 10 First switch subassembly 11 First bridge contact 12 Vacant contact 20 Second switch subassembly 21 Second bridge contact 22 Vacant contact 30 Third switch subassembly 31 Third bridge contact 32 Vacant contact 40 Drive shaft 41 Actuator N Second main terminal L Switch terminal L.1 Switch fixed contact L.21 . . . L.22 Switch fixed contacts L.3 Switch fixed contact A Lead A.31 . . . A.33 Lead fixed contacts IL Load current