System for operating a tap changer

Abstract

- Winding tap N of control winding 3 of transformer 4 N a tap changer 2 for switching between the two, said tap changer having a position sensor 5 for detecting the actual position of said tap changer 2; a drive unit 6 having a motor 14 and a gear mechanism 13; a control device 7 having an external signal interface 19; A system 1 for operating at least one tap changer, comprising: The drive device further includes a motor control unit and a motor drive unit, the motor control unit receiving the actual position of the tap changer from the position sensor and controlling the tap changer to winding tap N J From new winding tap N J+1 configured to operate the motor to switch to the control device 7 is adapted to operate the motor drive 8;

Description

[Technical Field]

[0001] The present invention relates to a system for operating at least one tap changer. [Background technology]

[0002] Tap changers, especially on-load tap changers, are used to change between winding taps of a transformer without interruption. Known on-load tap changers consist, for example, of a selector for preselecting the respective winding tap to be changed in a no-current state and a changeover switch for actually changing the current winding tap to the preselected new winding tap on load. To perform the changeover or to operate the corresponding components, known tap changers generally have a motor drive arranged in a tap changer head on the transformer cover. The motor drive and the motor drive are generally housed in a switchboard, which is connected to the motor drive via a cable line. Since the cable length is limited, it is necessary to locate the switchboard in close proximity to the transformer. Typically, the switchboard is directly attached to the transformer housing. Furthermore, the switchboard forms an interface for the user or the operator of the power distribution network and has corresponding input and output terminals for transmitting signals.

[0003] A drawback of this solution is that the switchboard is located in the immediate vicinity of the transformer due to the limited cable length, and therefore within a dangerous range for operators. Another drawback is that the devices and equipment required for measurement, control and regulation of the power distribution network are located far from the transformer, for example in the command or control room of the substation, resulting in high cable costs from the substation to the command room. Furthermore, the installation costs of the switchboard itself and the corresponding signal interface devices are high. Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore an object of the present invention to provide an improved concept for a system for operating a tap changer, which is compact, safely constructed, allows for simple installation and at the same time is low-cost. [Means for solving the problem]

[0005] This problem is solved by a system according to the independent claims. Further embodiments are given in the dependent claims.

[0006] The improved concept is based on the idea of ​​locating the components required to operate the tap changer where they are needed. In other words, the improved concept proposes integrating the motor electronic control device into the drive unit at the tap changer head together with the motor drive, the energy storage unit (if present), the motor, and the gear mechanism, and locating the signal interface for the operator in the substation control room, where the grid control equipment is also located. In this way, a switchboard at the transformer can be omitted, and cable costs can be reduced.

[0007] According to an improved concept, a system for operating at least one tap changer is provided, including a tap changer for switching between winding taps of a control winding of a transformer, the tap changer having a position sensor for detecting an actual position of the tap changer, in other words, the position sensor indicating at which winding tap of the control winding the tap changer is actually located, and the system further includes a drive unit having a motor and a gear mechanism, and a control unit having at least one external signal interface.

[0008] The external signal interface is used to input and output drive signals or power grid control signals.

[0009] The motor may be configured as a servo motor, a DC motor, or a brushless DC motor.

[0010] In this case, the drive device further comprises a motor controller and a motor driver. The motor controller is configured to receive the actual position of the tap changer from the position sensor and to operate the motor so as to cause the tap changer to switch from one winding tap to a new winding tap. Said operation is performed, for example, by relying on a voltage regulator which monitors the voltage of the distribution network and keeps said voltage of the distribution network within a set target range by means of switching commands for the tap changer or the control device. Alternatively, the control device may be controlled by a higher-level control device, for example a command room.

[0011] By locating the motor control and motor drive in the tap changer drive, the entire drive function is spatially located directly on the tap changer. This makes the structure of the system for operating the tap changer compact and reduces cable and installation costs. Since the power grid is omitted, the space required for the transformer is likewise reduced. The control device with the external interface for power grid control or the operator can be located near the transformer, without necessarily being necessary. This allows greater freedom in choosing the installation location of the control device, and the operator has the advantage that access to the system's control is no longer performed in a hazardous area.

[0012] Preferably, the motor control is configured as an electronic control, in particular as a programmable logic controller.

[0013] According to one embodiment, the tap changer has a tap changer head, by means of which the tap changer can be fastened to the housing of the transformer, and the drive is arranged directly on the tap changer head, which can be configured as a flange, for example, and can be present on the transformer cover.

[0014] According to another embodiment, the control device is spatially separated from the tap changer and the transformer and is located in particular in a command and / or control room of the substation.

[0015] According to another embodiment, the system includes a first wiring for internal communication between the drive and the control device. In other words, the first wiring is configured as a communication line. To this end, the drive and the control device each have a communication interface. These communication interfaces are used to transmit control signals detected by corresponding sensors in the tap changer and transmitted from the drive to the control device via the first wiring, and to control the tap changer. In this case, sensors such as an end position sensor indicating when the tap changer is in an end position, a temperature sensor measuring the temperature in the tap changer, a humidity sensor measuring the humidity of the insulating oil present in the tap changer, or a current sensor measuring the load current of the tap changer transmit corresponding measured values ​​to the drive device, in particular to the motor control of the drive device. The measured values ​​are digitized in the drive device or motor control and transferred to the control device. The actual position of the tap changer, detected by a position sensor, is also transmitted via the first wiring.

[0016] According to another embodiment, a bus system is used for internal communication, which preferably allows communication between multiple participants of the system and the large spatial distances that are possible between the participants via the bus system. Another advantage of using a bus system is the standardized communication protocol that is used for communication.

[0017] According to another embodiment, the system includes a second wiring for supplying a voltage to the driver.

[0018] According to another embodiment, the first wiring and the second wiring are formed as a common wiring, in other words, the first wiring and the second wiring can be formed as a hybrid wiring.

[0019] The system therefore contains at most two wires between the drive unit at the transformer and the control unit used for communication and power supply, thus reducing cable costs to the minimum possible.

[0020] According to another embodiment, the drive device comprises a power storage unit, which in particular ensures that an initiated change of the tap changer is completed even in the event of a fault, for example a power outage or a communication interruption.

[0021] According to one embodiment, the power storage unit is configured as a capacitor or a battery.

[0022] According to another embodiment, the tap changer includes a spring energy storage device. In this case, a drive shaft driven at a constant speed by a motor pulls a spring to a maximum point. After exceeding this maximum point, the spring instantly releases, thereby abruptly driving the drive shaft, which then operates the corresponding contacts to switch the tap changer to a new position.

[0023] According to one embodiment, the system includes a spring energy storage device and / or a power storage unit.

[0024] According to one embodiment, the control device includes an input unit. The input unit can be configured in any way to input data into the control device. For example, the input unit can be equipped on the control device as a local operating device and can include a rotary dial, buttons, a terminal for an external storage medium, such as a USB stick or an SD card, a touch screen, or a combination thereof, located on the control device. The input unit can also be configured as a mobile terminal device, such as a tablet or smartphone, and can be wirelessly connected to the control device.

[0025] Each of the control unit and the input unit may be configured as separate units or as a common component unit.

[0026] According to another embodiment, the control device includes an output for outputting data and signals related to the system, which can be done in any way, for example as a display on a screen or as digital or analog signals for processing in an adjacent or higher-level system, for example an operator system.

[0027] Each of the controller and output may be configured as separate devices or as a common component device.

[0028] According to one embodiment, the input and output are configured as separate devices or as a common device.

[0029] According to one embodiment, the control device, the input and the output are configured as a common device.

[0030] According to another embodiment, the control device can be omitted and the drive device can be controlled directly by an adjacent or higher-level system, for example an operator system, which in this case takes over the functions of the control device.

[0031] According to another embodiment, a system includes at least one second tap changer for switching between winding taps of a control winding of a transformer, wherein the at least one second tap changer has a position sensor for detecting an actual position of the at least one second tap changer. The system further includes at least one second drive having a motor and a second gear mechanism and associated with the at least one second tap changer. In this case, the at least one second drive further includes a second motor control and a second motor drive. The second motor control is configured to receive the actual position of the at least one second tap changer from the second position sensor and to operate the second motor to switch the at least one second tap changer from one winding tap to a new winding tap. In this case, the control device is configured to operate each motor drive of the system.

[0032] The motor controls of the system can be operated individually, together or in parallel. In this case, depending on the application, the second tap changer can be associated with the second transformer or with the same transformer as the first tap changer. These motor drives are operated individually, for example using phase shifters. For example, if several single-phase or three-phase transformers are operated in parallel, these motor controls can be operated together or in parallel. In this case, one tap changer is associated with each transformer.

[0033] According to another embodiment, a system includes a first tap changer, a second tap changer, and a third tap changer for switching between winding taps of a control winding of at least one transformer, each tap changer having a position sensor for detecting an actual position of the respective tap changer. The system according to this embodiment further includes a first drive unit, a second drive unit, and a third drive unit, each having a motor and a gear mechanism and associated with one of the three tap changers. In this case, each drive unit further includes a motor control unit and a motor drive unit. In this case, each motor control unit is configured to receive the actual position of each associated tap changer from the respective position sensor and to operate a respective motor to switch the associated respective tap changer from one winding tap to a new winding tap. The system includes a control unit configured to operate each motor control unit of the system individually, together, or in parallel.

[0034] According to one embodiment, the system includes first, second, and third tap changers for switching between winding taps of a control winding of at least one transformer. Each tap changer has a position sensor for detecting its actual position. The system according to this embodiment further includes first, second, and third drives, each of which has a motor and a gear mechanism and is associated with one of the three tap changers. Each drive further includes a motor controller and a motor driver. Each motor controller is configured to receive the actual position of its associated tap changer from the respective position sensor and to operate its respective motor to switch its associated tap changer from one winding tap to a new winding tap. According to this embodiment, one of the three motor controllers is defined as a master and is configured to operate the other two motor controllers, configured as slaves, together or individually. The system includes a controller configured to control a drive unit defined as the master of the system and indirectly operate two other drive units configured as slaves via the drive unit, and thus the controller is configured to operate each motor controller of the system directly or indirectly, individually, together or in parallel.

[0035] Further embodiments and implementations of the system can be derived directly from the different embodiments of the system.

[0036] The present invention will be described in detail below with reference to the drawings based on exemplary embodiments. Components that are identical or functionally identical or have the same effect may be designated by the same reference numerals. In some cases, identical components or components with the same function are only described for the drawing in which they first appear. The description is not necessarily repeated in subsequent drawings. [Brief explanation of the drawings]

[0037] [Figure 1] 1 shows a schematic representation of a first embodiment according to an improved concept; [Figure 2] 1 further illustrates the system according to FIG. [Figure 3] 2 shows a schematic representation of a second embodiment according to an improved concept. [Figure 4] 1 shows a schematic representation of a third embodiment according to an improved concept. [Figure 5] 1 shows a schematic representation of a fourth embodiment according to an improved concept. DETAILED DESCRIPTION OF THE INVENTION

[0038] In FIG. 1 a first embodiment of a system 1 according to the improved concept is shown diagrammatically.

[0039] The system 1 is connected to winding tap N of the control winding 3 of the transformer 4. J ,N J+1 ,N J+2 ,...,N N The transformer 4 is, for example, a power transformer present in a substation. For this purpose, the tap changer 2 includes, for example, a winding tap N N A selector (not shown) for preselecting in a no-current state the winding tap to which the current winding tap N should be switched. J Preselected new winding tap N J+1 and a diverter switch (not shown) for actually switching on load. The tap changer 2 is fixed to a housing 10 of the transformer 4, in particular to a transformer cover, by means of a tap changer head 9. The tap changer head 9 is configured, for example, as a flange. The drive module 6 is arranged directly on the tap changer head 9.

[0040] Furthermore, the tap changer 2 comprises a position sensor 5 which indicates the actual position of the tap changer 2 where this tap changer 2 is actually located and is arranged to transmit this as an analog or digital signal via a signal line S1 to the motor control 8. The transmission of the signal S1 can be carried out, for example, via a cable or wirelessly, for example by wireless communication. The motor control 8 is arranged in the drive 7 and is arranged as a programmable logic controller.

[0041] Furthermore, the system 1 includes a control device 7 which is configured to control a motor control unit 8. For this purpose, a first wiring 11 configured as a BUS communication line runs from the control device 7 to the drive unit 6. The drive unit 6 or the motor control unit 8 is operated depending on a voltage regulator 22 or a higher-level control unit 23, for example in a control room. The drive unit 6 is powered via a second wiring 12. The control device 7 is installed in a command room 21. Typically, a power distribution network control device (not shown) is also present in the command room 21.

[0042] Figure 2 further illustrates the system according to Figure 1, in which the drive unit 6 and the control unit 7 are shown in more detail. The system 1 according to Figure 2 is similar to the system 1 according to Figure 1 above, and only the differences and additional features will be described below.

[0043] 2, the drive device 6 included in the system 1 includes a motor 14 that operates the tap changer 2, particularly the selector and diverter switch, via a drive shaft 30 and a gear mechanism unit 13, a motor drive unit 15, and a power storage unit 16. The motor drive unit 8 is configured to obtain the actual position of the tap changer 2 from the position sensor 5 and operate the motor 14 and the motor drive unit 15. Furthermore, the drive device 6 has an internal communication interface 17 configured as a BUS communication interface, and communication with the control device 7 is performed via the BUS communication interface.

[0044] The control device 7 therefore also includes an internal communication interface 17 configured as a BUS communication interface, via which communication with the drive device 6 is carried out. The power storage unit 16 of the drive device 6 is powered by a power supply 20. The control device 7 further includes an input unit 18 configured as an output unit 18, via which an operator of the system 1 can manually operate the control device 7 and read data. For example, the input unit and the output unit 18 are configured as a touchscreen. The control device 7 further includes an external signal interface 19, which is used to electrically input and output operator signals or grid control signals. For example, via the external signal interface 19, switching signals can be input from a voltage regulator 22 and / or a higher-level control device 23 or a control room, and / or analog and / or digital signals can be output from sensors of the tap changer 2.

[0045] Figure 3 shows a schematic representation of a second embodiment of a system according to the improved concept. Figure 3 shows a possible application of system 1, in which the system 1 includes multiple tap changers and multiple transformation ratios. System 1 according to Figure 3 is similar to system 1 according to Figures 1 and 2 above, and only the differences and additional features will be described below.

[0046] According to this configuration, the system 1 includes a first tap changer 2 for switching between winding taps of the control winding of the first transformer 4 (FIG. 1), a second tap changer 24 for switching between winding taps of the control winding of the second transformer 25, and a third tap changer 26 for switching between winding taps of the control winding of the third transformer 27. Each of the tap changers 2, 24, 26 has a position sensor 5 for detecting the actual position of the respective tap changer 2, 24, 26. Furthermore, the system 1 includes a first drive 6 associated with the first tap changer 2, a second drive 28 associated with the second tap changer 24, and a third drive 29 associated with the third tap changer 26. Furthermore, each of the drive units 6, 28, 29 includes a motor drive unit 8 and a motor drive unit 15 (FIG. 2). Each motor control 8 is configured to receive the actual position of each tap changer 2, 24, 26 from the respective position sensor 5 and to operate a respective motor 14 (FIG. 2) to switch the respective tap changer 2, 24, 26. Furthermore, the system 1 includes a control device 7 configured to operate each motor control 8 of the three drives 6, 28, and 29. To this end, the control device 7 is connected to the drives 68, 29 via a communication line 11. Depending on the respective usage, the operations can be performed individually, together, or in parallel. In this case, the number of transformers 4, 25, 27, the number of tap changers 2, 24, 27 associated with the transformers, and the number of drives 6, 28, 29 are not limited to a predetermined number of three or any other number.

[0047] Figure 4 shows a schematic diagram of a third embodiment of the system according to the improved concept. Figure 4 shows another possible application of the system 1. In this case, the system 1 includes multiple tap changers and multiple transformers. The system 1 according to Figure 4 is similar to the description of the system 1 according to Figures 1 to 3 above, and only the differences and additional features will be described below.

[0048] The difference of this third embodiment with respect to the second embodiment illustrated in Figure 3 is that one of the three motor controls is defined as a master, i.e., a master motor control 36, which operates the tap changer 24. The master motor control 36 is then configured as a slave and is adapted to operate two further motor controls 8 associated with the tap changers 2 and 26, either together or individually. Similarly, the system 1 includes a control device 7 configured to control the master motor control 36 or the second drive 28 associated with the tap changer 24 of the system 1, and to indirectly operate the two further motor controls 8 or the drives 6 and 29, which are configured as slaves, via the master motor control 36 or the second drive 28. The control device 1 is therefore configured to operate the motor controls 8, 36 and the respective tap changers 2, 24, 26 of the system 1 directly or indirectly, individually, together or in parallel.

[0049] Figure 5 shows a schematic representation of a fourth embodiment of the system according to the improved concept. Figure 5 shows a possible application of the system 1 in a wind power plant 31. The system 1 according to Figure 5 is similar to the description of the system 1 according to Figures 1 to 4 above, and only the differences and additional features will be described below.

[0050] Wind power plants produce electrical energy at voltages up to 1000 V. This voltage is then transformed by a transformer to a medium voltage (10-30 kV) depending on the local power grid. The wind power plant 31 according to FIG. 5 includes a tower 32, on which a nacelle 33 and a hub 34 with three rotor blades 35 are located. The nacelle 33, also called a machine room, contains the components (not shown) necessary for converting the rotor's rotation into electrical energy, in particular the gear mechanism and the generator. According to this embodiment, the controllable transformer 4 of the system 1 is also located within the nacelle 33. In other words, the transformer 4, including the tap changer 2 according to the improved concept, is located within the nacelle 33. However, the transformer 4 is not shown for the sake of clarity. Furthermore, the drive unit 6 with the motor control unit 8 included in the system 1 is also located within the nacelle 33. The control unit 7 of the system 1 is located at the base of the tower 32 for easy access for the operator. Communication and energy supply between the control device 7 and the control unit 8 in the nacelle 33 are ensured via cables 11 and 12. Also in the case of this embodiment or application of the system 1, the possibility for a flexible spatial arrangement of the components for operating the tap changers, the simple construction due to the elimination of a switchboard and the low cable costs for the operator of the wind power plant are major advantages.

[0051] In summary, the improved concept provides a system for operating tap changers that allows for a very compact construction directly at the transformer, saves costs by eliminating the switchboard at the transformer, is easily constructed with particularly minimal cabling costs made possible by the BUS communication interface, and offers high flexibility in terms of the range of applications. [Explanation of symbols]

[0052] 1 System 2 Tap changer 3 Control Winding 4. Transformers 5 Position Sensor 6. Drive unit 7 Control Device 8 Motor control unit 9 Tap changer head 10 4 housing 11 1st wiring 12 2nd wiring 13 Gear mechanism 14 Motor 15 Motor drive unit 16 Power storage unit 17 Communication Interface 18 Input / output section 19 Signal Interface 20 Power supply 21 Control room 22 Voltage Regulator 23 Upper control device, control room 24 Second tap changer 25 Transformer No. 2 26 Third tap changer 27 Third Transformer 28 Second Drive Unit 29 Third Drive Unit 30 Drive shaft 31 Wind power generation facilities 32 Tower 33 Nacelle 34 Hub 35 rotor blades 36 Master motor control unit N J ,N J+1 ,…N N Winding Tap S1 signal

Claims

1. - Winding tap N of the control winding (3) of the transformer (4) Ｎ a tap changer (2) for switching between the two, said tap changer (2) having a position sensor (5) for detecting the actual position of said tap changer (2); a drive unit (6) comprising a motor (14) and a gear mechanism (13); a control unit (7) with an external signal interface (19); A system (1) for operating at least one tap changer, comprising: The drive device (6) further comprises a motor control (8) and a motor drive (15), the motor control (8) receiving the actual position of the tap changer (2) from the position sensor (5) and controlling the tap changer (2) to the winding tap N. Ｊ New winding tap N Ｊ＋１ configured to operate the motor (14) to switch to - the system (1) wherein said control device (7) is adapted to operate said motor drive (8).

2. - the tap changer (2) has a tap changer head (9) by means of which the tap changer (2) can be fixed to the housing (10) of the transformer (4); A system (1) according to claim 1, wherein the drive (6) is arranged directly on the tap changer head (9).

3. 3. The system (1) according to claim 1 or 2, wherein the control device (7) is spatially separated from the tap changer (2) and the transformer (4), and is located in particular in a command room and / or a control room of a substation.

4. The system (1) according to any one of claims 1 to 3, wherein the system (1) comprises a first wiring (11) for internal communication between the drive unit (6) and the control unit (7).

5. 5. The system (1) according to claim 4, wherein a bus system is used for said internal communication.

6. The system (1) according to any one of claims 1 to 5, further comprising a second wiring (12) for supplying a voltage to the drive device (6).

7. The system (1) according to any one of claims 1 to 6, wherein the drive device (6) further comprises a power storage unit (16).

8. - winding tap N of the control winding of the transformer (4, 25) Ｎ at least one second tap changer (24) for switching between the first and second tap changers, said at least one second tap changer (24) having a position sensor (8) for detecting the actual position of said at least one second tap changer (24); - at least one second drive (28) associated with said second tap changer (24), said drive (28) comprising a motor (14) and a gear mechanism (13), The at least one second drive device (28) further comprises a motor control (8) and a motor drive (15), the motor control (8) receiving the actual position of the at least one second tap changer (24) from the position sensor (8) and controlling the at least one second tap changer (24) to a winding tap N. Ｊ New winding tap N Ｊ＋１ configured to operate the motor (14) to switch to - said control device (7) is adapted to operate each motor drive (8) of said system (1);

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