Patent Grant
10373771
This application is the US-national stage of PCT application PCT/EP2015/059060 filed 27 Apr. 2015 and claiming the priority of German patent application 102014106997.8 itself filed 19 May 2014.
The present invention relates to a switching system for a tapped transformer and to a method of operating such a switching system.
For the purpose of changing the transmission ratio of tapped transformers under load, so-called on-load tap changers are provided, the structure and function of which are in principle known and that are designed to switch the winding taps of a control winding of the tapped transformer.
Such an on-load tap changer that is connected to the control winding commonly has a load diverter switch and a selector. The selector is provided for the purpose of powerless selection or, as the case may be, contacting, of the winding tap to be connected. Besides the selector in certain technical applications that require a greater control range, it has been moreover long known to additionally provide a preselector that, according to application, can be formed either as changeover selector for additive and subtractive switching of the control winding or as coarse selector for the linkage of the control winding to the beginning or to the end of the main winding of the tapped transformer.
The actual load transfer, however, is always carried out by the load diverter switch, namely from the previous winding tap to the new, preselected winding tap. For this purpose, the load diverter switch usually has mechanical switch contacts and resistance contacts, with the switch contacts serving for direct connection of the respective winding taps to the load dissipation, and the resistance contacts serving for temporary bridging by one or more transition resistances. The developments of the past years, however, lead away from load diverter switches with mechanical switch contacts and toward using vacuum switching tubes or semiconductor switching components, in particular circuit breaker components, as switching components for high voltages and currents, for example thyristors, GTOs, IGBTs, and other components.
Integrated on-load tap changers that are also called load selectors, are another genus of on-load tap changers. In these, the load diverter switch and the fine selector are constructed as one unit. Upon actuation, the winding tap to be switched is preselected and subsequently switched in a single step. This form of realization of an on-load tap changer can also have a preselector that is arranged either outside or inside the housing of the on-load tap changer, specifically in an insulation medium, preferably in insulation oil.
It is already known from DE 960 303 to provide an on-load tap changer with selector arms, of which in each case one selector arm is current-carrying and is in contact with a tap of a control winding of the tapped transformer during stationary operation. Moreover provided is a further auxiliary tap that is connected to the end of the main winding of the tapped transformer, which main winding is connected upstream of the control winding. The current-carrying selector arm is in contact with this auxiliary tap when the so-called changeover switch for the control winding, which in this technical context is also referred to as fine winding, switches over. This changeover switch in turn is also connected to the upstream main winding on the one side and to the winding ends of the control winding on the other side such that the voltage of the control winding is added to or subtracted from the voltage of the upstream main winding according to the position of the changeover switch contact. This type of electrical circuitry has become known as so-called changeover circuit.
From DE 23 58 885 it is furthermore already known to connect a so-called coarse winding upstream of a fine winding with the beginning of the main winding being connected to the tapped transformer. Provided for the coarse winding is a changeover switch, the center contact of which is connected to the beginning of the fine winding and the external contacts of that are connected to the beginning and the end of the coarse winding. According to the position of the changeover switch, the voltage of the coarse winding is thereby added or it is not added to the voltage of the main winding and to the voltage of the fine winding. This type of electrical circuitry has become known as so-called coarse step.
Finally, as already known from DE 29 36 534 A1, there is a switch subassembly for a transformer stage selector, in which a main winding, a fine winding equipped with taps for selector arms for voltage adjustment, and at least one coarse winding arranged at the same leg of the transformer are provided per phase; in which a changeover switch is connected with its external contacts to the beginning and the end of each coarse winding, and the center contact of each changeover switch is connected to the beginning of the coarse winding having the next higher potential; and in which an auxiliary tap is provided that is connectable to a coarse winding and to the current-carrying selector arm. In this known switching system, it is provided that the center contact of the changeover switch connected to the coarse winding with the highest potential is connected to the center contact of a reversing changeover switch; that the external contacts of the reversing changeover switch are connected to the beginning and the end of the fine winding; that the auxiliary tap is connected to the center contact of an auxiliary changeover switch, the external contacts of that are connected to the end of the upstream coarse winding and to the center contact of an auxiliary changeover switch that is connected to the next upstream coarse winding in the same manner, whereas the auxiliary changeover switch connected to the coarse winding immediately downstream of the main winding is connected with both external contacts to the coarse winding; and that the contacts of each changeover switch, of the reversing changeover switch, and of each auxiliary changeover switch are arranged at different levels of the stage selector.
What is disadvantageous in the circuits as known from the prior art is that a resistor known as tie-in resistors has to be provided in order to ensure that the potential of the control winding or of the fine winding, as the case may be, takes a defined value when switching over the changeover switch. This is the case because the control winding is electrically floating, that is, not galvanically linked, at the point of time of switching over the switch over contact. Via capacitive couplings, the control winding therefore takes a potential that is unpredictable, and this can in turn lead to considerable voltages at the pre-selector, which voltages in turn can be technically controlled only with difficulty.
The object of the present invention is therefore to specify a switching system for a tapped transformer as well as a method of operating such a switching system in which the previously mentioned disadvantages are eliminated.
This object is achieved according to the invention by the subject matter of the independent claims. Advantageous developments and embodiments of the invention are described in the corresponding dependent claims.
According to a first aspect of the invention, there is proposed a switching system for a tapped transformer comprising
In this way, a switching system is provided in which all sections of each main winding, of each coarse winding as well as of each control winding of the tapped transformer are galvanically linked, that is, not electrically floating, at each point of time during each switch over. An additional tie-in resistor is therefore not needed. With this switching assembly it is moreover possible to switch a control range that has the fourfold voltage range of the control winding by additively or, as the case may be, subtractively connecting the various parts of the main winding, the coarse winding, as well as the control winding, that is, by correspondingly alternatingly reversing the polarity.
It can be provided that there is a drive shaft, at which the bridge contacts are nonrotatably arranged.
It can be provided that the drive shaft is coupled to an actuator.
It can be provided that the actuator comprises a motor drive and/or a direct drive and/or a manual drive and/or a spring energy storage device.
It can be provided that the first switch subassembly comprises
It can be provided that the second switch subassembly
It can be provided that the third switch subassembly comprises
It can be provided that the respective fixed contacts in each switch subassembly are arranged rotationally symmetrically and/or on a circular orbit around the drive shaft.
It can be provided that the individual switch subassemblies are formed to be electrically insulated from each other.
It can be provided that the switch subassemblies are arranged in different horizontal planes.
According to a second aspect of the invention, there is proposed a switching system for a tapped transformer comprising
It can be provided that the switching system comprises
It can be provided that
It can be provided that
Particularly preferably, it switches a current path, in particular, from the main terminal through the control winding, or at least through a part of it, in particular to the lead, and/or it switches the first control terminal and the switch terminal or the control winding, or at least a part of it, to the main terminal and to the lead or to the main winding and/or to the coarse winding in each operating position and/or during each switch over process.
It can be provided that the main winding, the coarse winding, and the control winding are galvanically separated from one another.
According to a third aspect of the invention, there is proposed a tapped transformer comprising
It can be provided that
It can be provided that the main winding, the coarse winding, and the control winding are galvanically separated from one another.
According to a fourth aspect of the invention, there is proposed a method of operating a switching system that is in particular designed according to the first or second aspect, wherein
According to a fifth aspect of the invention, there is proposed a method of operating an electrical system comprising
It can be provided that, in the first stationary operating position,
It can be provided that, in the second stationary operating position,
It can be provided that, in the third stationary operating position,
It can be provided that, in the fourth stationary operating position,
The electrical system can comprise a tapped transformer as proposed according to the third aspect, for example, or it can be designed like a tapped transformer as proposed according to the third aspect.
The explanations and exemplifications regarding one of the aspects of the invention, in particular regarding individual features of this aspect, also apply correspondingly for the other aspects of the invention.
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
Shown in
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.
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.
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.
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.
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.
Shown in
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.
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.
Shown in
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.
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.
Shown in
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.
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.
Shown in
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 106 997 | May 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/059060 | 4/27/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/176918 | 11/26/2015 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3555403 | Matzl et al. | Jan 1971 | A |
| 3643154 | Van Riemsdijk | Feb 1972 | A |
| 20100059356 | Hammer | Mar 2010 | A1 |
| 20140167529 | Teising | Jun 2014 | A1 |
| 20150162144 | Panosyan | Jun 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 2798959 | Nov 2011 | CA |
| 960303 | Mar 1957 | DE |
| 960303 | Mar 1957 | DE |
| 1942567 | Mar 1971 | DE |
| 2358885 | Jun 1975 | DE |
| 2936493 | Mar 1981 | DE |
| 2936493 | Mar 1981 | DE |
| 2936534 | Mar 1981 | DE |
| 2936534 | Mar 1981 | DE |
| 1241822 | Aug 1971 | GB |
| Number | Date | Country | |
|---|---|---|---|
| 20170062146 A1 | Mar 2017 | US |
