Patent Application
20240062969
The present disclosure relates to a switch unit for a step transformer and to a step transformer having a switch unit.
Switch units, in particular on-load tap-changers, usually consist of a diverter switch and a selector. The actuation of the on-load tap-changer usually takes place via a drive, which is arranged on the outside of the tank of a step transformer. The drive in this case has a motor which is coupled to the on-load tap-changer via a gear. The energy required for the operation of the on-load tap-changer is usually drawn from the low-voltage grid. For this purpose, a low-voltage distribution board, a miniature circuit breaker, and a connecting lead between the low-voltage distribution board and the drive are required. This represents a considerable degree of complexity, in particular in the case of small transformers, for example pole transformers.
In an embodiment, the present disclosure provides a switch unit that is for a step transformer. The switch unit has: ]a controller; a motor; and an on-load tap-changer. The controller controls the motor, which actuates the on-load tap-changer. The controller draws energy, required for actuating and controlling the motor, directly from a low voltage winding of the step transformer.
Subject matter of the present disclosure will be described in even greater detail below based on the exemplary figures. All features described and/or illustrated herein can be used alone or combined in different combinations. The features and advantages of various embodiments will become apparent by reading the following detailed description with reference to the attached drawings, which illustrate the following:
Aspects of the present disclosure provide a switch unit for a step transformer that is supplied with energy in a simple and uncomplicated manner, and thus, is configured in a compact and safe design.
Aspects of the present disclosure provide a step transformer having a switch unit which is configured in a simple, compact, and safe manner.
The present disclosure provides a switch unit for a step transformer, comprising a control device, a motor, and an on-load tap-changer; where the control device controls the motor, which actuates the on-load tap-changer; the control device draws energy, required for actuating and controlling the motor, directly from a low voltage winding of the step transformer.
Because the energy required for the operation of the switch unit is drawn directly from the low voltage winding of a step transformer, it is possible to produce a self-contained system. A combination of external low-voltage distribution boards, miniature circuit breakers, and leads is no longer necessary for the energy supply. A switch device is made available that needs no external connections after installation in the step transformer. Not only is the energy drawn directly from the low voltage winding in this case, but also the voltage on the low voltage side is monitored at the same time. These measurements are performed by means of the control device and are used to regulate the voltage, in particular by actuating the switch unit, in particular of the on-load tap-changer. The whole mounting of the system can take place in the factory. As part of the installation, the step transformer only has to be connected between the high-voltage grid and the low voltage grid. An entirely autonomous system is created.
The control device furthermore draws the energy, required for actuating and controlling the motor, directly from the low voltage winding inside the step transformer. All the cabling between the switch unit and the active part remains inside the transformer housing. The step transformer thus only has to be connected between the high-voltage grid and the low voltage grid. The wiring of the switch unit to an external energy supply becomes obsolete.
The control device controls the on-load tap-changer depending on the voltage at the low voltage winding. Thus, windings of the tap winding of the high-voltage winding are moved to the open and closed position in order to keep the voltage at the low voltage winding constant.
The switch unit can be designed in any desired manner, where the control device has a first connection and a second connection; the control device is connected to a first terminal and a second terminal of the low voltage winding via the first connection and the second connection by means of a first lead and a second lead.
The connections of the control device are arranged inside a housing of the switch unit and hence inside the step transformer. The leads for the energy supply of the switch unit thus also run inside the step transformer.
The switch unit can be designed in any desired manner, where the first terminal is connected to a first end of the low voltage winding; the second terminal is connected to a second end of the low voltage winding; the first terminal and the second terminal are arranged inside or in the interior of the step transformer.
The first and the second end of the low voltage winding are configured as leads and extend from the interior of the step transformer through the transformer housing to the outside. Bushings can be used for this. The ends or leads connect the low voltage winding to the low voltage grid. The high-voltage winding also has a first end and a second end. These ends are also configured as leads and connect the high-voltage winding to the high-voltage grid.
The switch unit can be designed in any desired manner, where the switch unit comprises a housing with a first part and a second part; the first part of the housing projects at least partially from the transformer housing.
The switch unit can be designed in any desired manner, where the control device is arranged in the first part of the housing and the motor and the on-load tap-changer are arranged in the second part of the housing inside the step transformer.
Although the first part of the housing projects from the step transformer, the interior of the first part of the housing adjoins the interior of the step transformer. The leads which connect the control device to the connections of the low voltage winding run inside the switch unit and hence also inside the step transformer. The interior of the housing of the switch unit and the interior of the step transformer form a common interior inside which the leads of the sensors and the energy supply are placed. External cabling which serves to supply energy is superfluous.
According to a second aspect, the present disclosure provides a step transformer having a switch unit, comprising a transformer housing, a high-voltage winding which is connected to a high-voltage grid, a low voltage winding which is connected to a low voltage grid.
After being mounted in the factory, the step transformer having the switch unit is a complete system suitable for being connected directly. The step transformer only has to be connected to the grid and is directly ready for operation. It is no longer necessary to install complex connections for the energy supply of the switch unit. Furthermore, a current sensor which is connected to the control device of the switch unit is arranged in the interior of the step transformer.
Aspects of the present disclosure and their advantages are described in more detail below with reference to the attached drawings.
The control device 6 comprises a power section 7, with a converter and a control unit 8. The control device 6 also detects the tap position of the on-load tap-changer 1. The switch unit 11 is arranged at least partially in the interior of the step transformer 10 such that a first part 9.1 of the housing 9 of the switch unit 11 projects at least partially from the transformer housing 12 and a second part 9.2 is arranged in the interior of the step transformer 10. The control device 6 is arranged in the first projecting part 9.1 of the housing 9 of the switch unit 11. The on-load tap-changer 1 is arranged in the second part 9.2 of the housing 9. The interior of the first part 9.1 of the housing 9 is connected to the interior of the transformer housing 12.
The step transformer 10 has a high-voltage winding 30 and a low voltage winding 21. The high-voltage winding 30 is connected to a high-voltage grid 31, in particular to a voltage of no more than 40.5 kV. The selector 3 of the on-load tap-changer 1 is connected to the high-voltage winding 30. The high-voltage winding 30 has a main winding and a tap winding. By actuating the on-load tap-changer 1, individual windings of the tap winding of the high-voltage winding 30 are moved to the closed or open position and the voltage on the high-voltage winding 30 thus increased or reduced and the voltage at the low voltage winding 21 thus maintained. The low voltage 21 and the high-voltage winding 30 are arranged around a ferromagnetic yoke or a ferromagnetic core. When the on-load tap-changer 1 is actuated, the motor 5 drives the diverter switch 2 and the selector 3.
The low voltage winding 21 is connected to the low voltage grid 32. Whereas the high-voltage winding 31 is connected to the distribution grid, the low voltage winding 21 is connected to the end consumers. A voltage of 120V to 230V is usually present at the low voltage winding 21. The low voltage winding 21 has a first end 22 and a second end 23, wherein the second end is arranged opposite the first end 22. The switch unit 11, in particular the control device, is connected to the first end 22 and the second end 23 via connections 26, 29, leads 24, 27, and terminals 25, 28. This connection serves to supply energy to the switch unit 11. The connections 26, 29 at the switch unit 11 and also the terminals 25, 28 at the low voltage winding 21 are arranged in the interior of the step transformer 10, i.e. in the transformer housing 12 and in the housing of the switch unit 11. The switch unit 11, in particular the control device 6 and the motor 5, is fed directly via the low voltage winding 21.
A voltage which is present between the first end 22 and the second end 23 of the low voltage winding 21 is furthermore also measured via the leads 24, 27. This serves to regulate and control the switch unit 11. A current sensor 13 is arranged at the first end 22 of the low voltage winding 21 and connected to the switch unit 11, in particular the control device. Alternatively, it can also be arranged at the second end 23 of the low voltage winding 21. The current sensor 13 is also attached in the interior of the step transformer 10, directly on the low voltage winding 21 inside the transformer housing 12. The direction of the flow of current in the low voltage winding 21, which is connected to the low voltage grid 32, is determined with the aid of the current sensor 13. A determination is thus made, in conjunction with the measurement and the voltage between the two ends 22 and 23 of the low voltage winding 21, as to whether energy is fed into the low voltage grid 32 or is drawn therefrom.
While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 101 236.8 | Jan 2021 | DE | national |
This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2021/086933, filed on Dec. 21, 2021, and claims benefit to German Patent Application No. DE 10 2021 101 236.8, filed on Jan. 21, 2021. The International Application was published in German on Jul. 28, 2022 as WO 2022/156980 A1 under PCT Article 21(2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/086933 | 12/21/2021 | WO |
