System for actuating a tap changer

Abstract

The invention relates to a system (1) for actuating at least one tap changer, comprising - a tap changer (2) for changing over between winding taps NN of a control winding (3) of a transformer (4), wherein the tap changer (2) has a position detector (5) for detecting the current position of the tap changer (2), - a drive unit (6) having a motor (14) and a transmission (13), - a control unit (7) having an external signal interface (19), wherein - the drive unit (6) furthermore comprises a motor controller (8) and a motor driver (15), wherein the motor controller (8) is designed to receive the current position of the tap changer (2) from the position detector (5) and to actuate the motor (14) such that the tap changer (2) is changed over from a winding tap NJ to a new winding tap NJ+1, - the control unit (7) is designed to actuate the motor controller (8).

Description

[0001] SYSTEM FOR ACTUATION OF A TAP SWITCH

[0002] The invention relates to a system for actuating at least one step switch.

[0003] Tap changers, particularly on-load tap changers, are used for uninterrupted switching between the winding taps of a transformer. Common on-load tap changers, for example, consist of a selector for powerless pre-selection of the respective winding tap to which switching is to take place, and a load transfer switch for the actual load transfer from the previous winding tap to the new, pre-selected winding tap. To carry out the switching or operate the corresponding components, common tap changers have a motor drive, which is usually located on the tap changer head on the transformer cover. The motor control unit, including the motor driver, is usually housed in a control cabinet connected to the motor drive via a cable. Since the cable length is limited, it is necessary to locate the control cabinet in the immediate vicinity of the transformer.The control cabinet is therefore usually mounted directly on the transformer housing. The control cabinet also forms the interface to the user or the power grid operator and features corresponding input and output terminals for signal transmission.

[0004] The disadvantage of this solution is that, due to the limited cable length, the control cabinet is located in close proximity to the transformer, thus creating a hazardous area for the operator. A further disadvantage is that the equipment and devices required for the measurement, control, and regulation of grids, and which require signals from the control system, are located away from the transformer, for example, in a substation building or a control room. This results in a significant amount of cabling from the transformer to the building or control room. Furthermore, the installation of the control cabinet itself and the setup of the corresponding signal interfaces are very complex.

[0005] It is therefore an object of the present invention to provide an improved concept for a system for actuating a step switch which is compact and safe, enables simple assembly and is at the same time cost-effective.

[0006] This problem is solved by the subject matter of the independent claim. Further embodiments are the subject matter of the dependent claims. The improved concept is based on the idea of ​​spatially relocating the components relevant for actuating the tap changer to where they are needed. In other words, according to the improved concept, it is proposed to integrate the electronic motor control system, including the motor driver and, if present, an energy storage device, including the motor and gearbox, directly into the drive unit on the tap changer head, and to relocate the signal interfaces for the operator to the substation's operating building, where the network control technology devices are also located. In this way, the control cabinet on the transformer can be completely eliminated, and the amount of cabling is reduced.

[0007] According to the improved concept, a system for actuating at least one tap changer is provided, which comprises a tap changer for switching between winding taps of a control winding of a transformer, wherein the tap changer has a position sensor for detecting the current position of the tap changer. In other words, the position sensor indicates which winding tap of the control winding the tap changer is currently located on. Furthermore, the system comprises a drive unit having a motor and a gear, as well as a control unit having at least one external signal interface.

[0008] The external signal interface is used for the input and output of operator signals or the signals of the network control system.

[0009] The motor is designed, for example, as a servo motor, DC motor or brushless DC motor.

[0010] The drive unit further comprises a motor controller and a motor driver. The motor controller is configured to receive the current position of the tap changer from the position sensor and to actuate the motor in such a way that the tap changer switches from one winding tap to a new winding tap.

[0011] The control unit is designed to operate the motor control. Operation occurs, for example, depending on a voltage regulator that monitors the mains voltage and maintains it within a specified target range via switching commands to the tap changer or the control unit. Alternatively, the control unit can also be controlled by a higher-level control device, such as a control room. By relocating the motor control and motor driver into the drive unit of the tap changer, the entire drive functionality is spatially located directly at the tap changer, which makes the design of the system for operating the tap changer more compact and reduces cabling and installation costs. The space required on-site at the transformer is also reduced, as the control cabinet is eliminated.The control unit with the external interfaces to the network control system or the operator does not necessarily have to be located near the transformer, which gives the operator more freedom in selecting the location of the control unit and has the additional advantage that access to the system control is no longer in the danger zone for the operator.

[0012] The engine control is preferably designed as an electronic control, in particular as a programmable logic control.

[0013] According to one embodiment, the tap changer has a tap changer head, by means of which the tap changer can be fixed to a transformer housing, with the drive unit being arranged directly on the tap changer head. The tap changer head can, for example, be designed as a flange and located on the transformer cover.

[0014] According to a further embodiment, the control unit is arranged spatially separated from the tap changer and the transformer, in particular in an operating building of a substation and / or a control room.

[0015] According to a further embodiment, the system comprises a first line for internal communication between the drive unit and the control unit. In other words, the first line is designed as a communication line. For this purpose, the drive unit and the control unit each have a communication interface. The communication interface serves to transmit the tap changer signals, which are detected by corresponding sensors in the tap changer and transmitted via the first line from the drive unit to the control unit, as well as to control the tap changer.The sensors, such as an end-position sensor that indicates when the tap changer is in an end position, a temperature sensor that measures the temperature inside the tap changer, a humidity sensor that measures the humidity of the insulating oil in the tap changer, or a current sensor that measures the tap changer's load current, transmit the corresponding measured values ​​to the drive unit, specifically the drive unit's motor control. There, the measured values ​​are digitized and then transmitted to the control unit. The current position of the tap changer, which is detected by the position sensor, is also transmitted via the first line.

[0016] According to another embodiment, a bus system is used for internal communication. The advantage of using a bus system is the possibility of data exchange or communication between multiple system participants, as well as the large spatial distance that a bus system enables between the participants. Another advantage of using a bus system is the standardized communication protocols used for communication.

[0017] According to a further embodiment, the system comprises a second line for supplying voltage to the drive unit.

[0018] According to a further embodiment, the first and second lines are formed as a common line. In other words, the first and second lines can also be designed as a hybrid line.

[0019] The system therefore comprises a maximum of two cables between the drive unit on the transformer and the control unit, which serve for communication and power supply. This reduces the amount of cabling to a minimum.

[0020] According to a further embodiment, the drive unit comprises an electrical energy storage device. The energy storage device ensures, in particular, that a switching operation of the tap changer is completed even in the event of a malfunction, such as a power outage or a loss of communication.

[0021] According to one embodiment, the electrical energy storage device is designed as a capacitor or as a battery.

[0022] According to a further embodiment, the tap changer comprises a mechanical spring energy storage device. An output shaft driven by the motor at a constant speed preloads a storage spring to a maximum point. Once this maximum point is exceeded, the storage spring suddenly relaxes, thereby abruptly driving a drive shaft, which in turn actuates the corresponding contacts to switch the tap changer to the new position.

[0023] According to one embodiment, the system comprises a spring energy store and / or an energy store. According to one embodiment, the control unit comprises an input unit. For the input of data into the control unit, the input unit can be designed as desired. The input unit can, for example, be designed as a local operating unit on the control unit and have a rotary dial arranged on the control unit, buttons, a connection for external storage media, for example a connection for a USB stick or an SD card, or a touchscreen, or combinations thereof. Likewise, the input unit can be designed as a mobile device, for example a tablet or smartphone, and can be connected wirelessly to the control unit.

[0024] The control unit and the input unit can each be designed as separate units or as a common structural unit.

[0025] According to a further embodiment, the control unit comprises an output unit for outputting data and signals relating to the system. The output can be provided in any desired manner, for example, visualized on a screen or as digital or analog signals for further processing in an adjacent or higher-level system, such as the operator system.

[0026] The control unit and the output unit can each be designed as separate units or as a common structural unit.

[0027] According to one embodiment, the input unit and the output unit are designed as separate units or as a common unit.

[0028] According to one embodiment, the control unit, the input unit and the output unit are formed as a common unit.

[0029] According to a further embodiment, the control unit can be omitted and the drive unit can be controlled directly by an adjacent or higher-level system, for example, the operator system. In this case, the operator system maps the functionality of the control unit.

[0030] According to a further embodiment, the system comprises 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 second position sensor for detecting the current position of the at least one second tap changer.Furthermore, the system comprises at least one second drive unit having a second motor and a second gear and associated with at least one second tap changer, wherein the at least one second drive unit further comprises a second motor controller and a second motor driver, wherein the second motor controller is configured to receive the current position of the at least one second tap changer from the second position sensor and to actuate the second motor such that the at least one second tap changer is switched from one winding tap to a new winding tap. The control unit is configured to actuate each motor controller of the system.

[0031] The system's motor controls can be operated individually, jointly, or in parallel. Depending on the application, the second tap changer can be assigned to a second transformer or to the same transformer as the first tap changer. Separate operation of the motor controls occurs, for example, in phase-shifting applications. Joint or parallel operation of the motor controls occurs, for example, when several single-phase or three-phase transformers are operating in parallel. In this case, each transformer has its own tap changer assigned to it.

[0032] According to a further embodiment, the system comprises a first, a second and a third tap changer for switching between winding taps of a control winding of at least one transformer, wherein each tap changer has a position sensor for detecting the current position of the respective tap changer.The system according to this embodiment further comprises a first, a second, and a third drive unit, each having a motor and a gearbox and each associated with one of the three tap changers, wherein each drive unit further comprises a motor controller and a motor driver, wherein each motor controller is configured to receive the current position of the respective associated tap changer from the respective position sensor and to actuate the respective motor such that a switching of the respective associated tap changer from one winding tap to a new winding tap is performed. The system comprises a control unit configured to actuate each motor controller of the system separately or jointly or in parallel.

[0033] According to a further embodiment, the system comprises a first, a second and a third tap changer for switching between winding taps of a control winding of at least one transformer, wherein each tap changer has a position sensor for detecting the current position of the respective tap changer.The system according to this embodiment further comprises a first, a second, and a third drive unit, each having a motor and a gearbox and each being assigned to one of the three tap changers, wherein each drive unit further comprises a motor controller and a motor driver, wherein each motor controller is configured to receive the current position of the respective assigned tap changer from the respective position sensor and to actuate the respective motor such that a switching of the respective assigned tap changer from one winding tap to a new winding tap is carried out. According to this embodiment, one of the three motor controllers is defined as the master and is configured to actuate the two other motor controllers, which are configured as slaves, jointly or separately.The system comprises a control unit configured to control the drive unit defined as the master of the system and, via this drive unit, indirectly actuate the two other drive units, which are configured as slaves. Consequently, the control unit is configured to actuate each motor control of the system directly or indirectly, separately or jointly, or in parallel.

[0034] Further embodiments and implementations of the system will become apparent from the various embodiments of the system.

[0035] The invention will now be explained in detail using exemplary embodiments with reference to the drawings. Components that are identical, functionally identical, or have an identical effect may be provided with identical reference numerals. Identical components or components with identical functions may only be explained with reference to the figure in which they first appear. The explanation is not necessarily repeated in subsequent figures.

[0036] They show:

[0037] Figure 1 shows a first embodiment of a system according to the improved concept in a schematic representation;

[0038] Figure 2 is a further schematic representation of the system from Figure 1;

[0039] Figure 3 shows a second embodiment of the system according to the improved

[0040] Concept in a schematic representation;

[0041] Figure 4 shows a third embodiment of the system according to the improved concept in a schematic representation;

[0042] Figure 5 shows a fourth embodiment of the system according to the improved concept in a schematic representation. Figure 1 shows a first embodiment of a system 1 according to the improved concept in a schematic representation.

[0043] The system 1 comprises a tap changer 2 for switching between winding taps Nj, Nj + i, NJ + 2, N N a control winding 3 of a transformer 4. Transformer 4 is, for example, a power transformer located in a substation. For switching, tap changer 2 has, for example, a selector (not shown) for power-free preselection of the respective winding tap N Nto which the switchover is to take place, and a load changeover switch (not shown) for the actual load switching from the previous winding tap Nj to the new, preselected winding tap N J+i The tap changer 2 is attached to a housing 10 of the transformer 4, in particular to the transformer cover, by means of a tap changer head 9. The tap changer head 9 is designed, for example, as a flange. A drive module 6 is arranged directly on the tap changer head 9.

[0044] The tap changer 2 further comprises a position sensor 5, which is designed to detect the current position of the tap changer 2, i.e. the winding tap Nj, N J+ i, NJ + 2, ..., N Nat which the step switch 2 is currently located, and to transmit this signal in the form of an analog or digital signal via a signal connection S1 to a motor controller 8. The signal S1 can be transmitted via a cable or wirelessly, for example, via radio. The motor controller 8 is arranged in the drive unit 6 and is designed as a programmable logic controller.

[0045] The system 1 also comprises a control unit 7, which is designed to control the motor controller 8. For this purpose, a first line 11 is provided from the control unit 7 to the drive unit 6, which is designed as a BUS communication line. The drive unit 6 or the motor controller 8 is actuated depending on a voltage regulator 22 or a higher-level control device 23, such as a control room. The drive unit 6 is supplied with voltage via a second line 12. The control unit 7 is housed in an operating building 21, where the network control technology devices (not shown) are usually also located.

[0046] Figure 2 shows the system from Figure 1 in a further, schematic representation, with the drive unit 6 and the control unit 7 being shown in detail. With regard to system 1 from Figure 2, reference is made analogously to the previous explanations for system 1 from Figure 1, and only the differences and additional features are discussed below.

[0047] The drive unit 6 comprised by the system 1 accordingly comprises a motor 14, which actuates the tap changer 2, in particular the selector and the load transfer switch, via a drive shaft 30 and a gear 13, as well as a motor driver 15 and an energy storage device 16. The motor controller 8 is designed to read the current position of the tap changer 2 from the position sensor 5 and to actuate the motor 14 and the motor driver 15. Furthermore, the drive unit 6 has an internal communication interface 17, which is designed as a BUS communication interface and via which communication with the control unit 7 is realized.

[0048] The control unit 7 therefore also comprises an internal communication interface 17, which is designed as a BUS communication interface and via which communication with the drive unit 6 takes place. The energy storage device 16 of the drive unit 6 is supplied with energy via an energy supply device 20. The control unit 7 furthermore has an input unit 18, which is also designed as an output unit 18 and via which an operator of the system 1 can manually operate the control unit 18 and read out data. For example, the input and output unit 18 is designed as a touchscreen. In addition, the control unit 7 comprises an external signal interface 19, which is used for the electrical input and output of operator signals or the signals from the network control technology. For example, switching signals from the voltage regulator 22 and / or the higher-level control device 23 orcontrol room, and / or analog and / or digital signals from the sensors of the tap changer 2.

[0049] Figure 3 shows a second embodiment of the system according to the improved concept in a schematic representation. Figure 3 shows a possible application of system 1, wherein system 1 comprises several tap changers and several transformers. With regard to system 1 in Figure 3, reference is made analogously to the previous explanations of system 1 in Figures 1 and 2, and only the differences and additional features are discussed below.

[0050] According to this embodiment, the system 1 comprises, in addition to a first tap changer 2 for switching between winding taps of a control winding (Figure 1) of a first transformer 4, a second tap changer 24 for switching between winding taps of a control winding of a second transformer 25 and a third tap changer 26 for switching between winding taps of a control winding of a third transformer 27. Each tap changer 2, 24, 26 has a position sensor 5 for detecting the current position of the respective tap changer 2, 24, 26. The system 1 further comprises a first drive unit 6, which is assigned to the first tap changer 2, a second drive unit 28, which is assigned to the second tap changer 24, and a third drive unit 29, which is assigned to the third tap changer 26.Each drive unit 6, 28, 29 further comprises a motor controller 8 and a motor driver 15 (Figure 2). Each motor controller 8 is designed to receive the current position of the respective step switch 2, 24, 26 from the respective position sensor 5 and to actuate the respective motor 14 (Figure 2) such that a switching of the respective step switch 2, 24, 26 occurs. The system 1 further comprises a control unit 7, which is designed to actuate each motor controller 8 of the three drive units 6, 28, and 29. For this purpose, the control unit 7 is connected to the drive units 6, 28, 29 via communication lines 11. Depending on the respective application, the actuation can take place separately, jointly, or in parallel.The number of transformers 4, 25, 27 and the tap changers 2, 24, 27 associated with them, including drive units 6, 28, 29 in system 1 is not limited to the specific number three or any other number.

[0051] Figure 4 shows a third embodiment of the system according to the improved concept in a schematic representation. Figure 4 shows another possible application of system 1, wherein system 1 comprises multiple tap changers and multiple transformers. With regard to system 1 in Figure 4, reference is made analogously to the preceding explanations for system 1 in Figures 1 to 3, and only the differences and additional features are discussed below.

[0052] The difference between this third embodiment and the second embodiment described in Figure 3 is that one of the three motor controllers is defined as the master, namely the master motor controller 36, which actuates the tap changer 24. The master motor controller 36 is designed to jointly or separately actuate the two other motor controllers 8, which in this case are designed as slaves and are assigned to the tap changers 2 and 26. The system 1 also comprises a control unit 7, which is designed to control the master motor controller 36 or the second drive unit 28 of the system 1, which are assigned to the tap changer 24, and via these to indirectly actuate the two other motor controllers 8 or the drive units 6 and 29, which are designed as slaves.Consequently, the control unit 1 is designed to operate each motor control 8, 36 and thus each step switch 2, 24, 26 of the system 1 directly or indirectly, separately or jointly or in parallel.

[0053] Figure 5 shows a fourth embodiment of the system according to the improved concept in a schematic representation. Figure 5 shows a possible application of system 1 in a wind turbine 31. With regard to system 1 from Figure 5, reference is made analogously to the previous explanations of system 1 from Figures 1 to 4, and only the differences and additional features are discussed below.

[0054] Wind turbines produce electrical energy with a voltage of up to 1000 volts. This voltage is then transformed by transformers to medium voltage (10 to 30 kV), depending on the local grid voltage. The wind turbine 31 according to Figure 5 comprises a tower 32 on which a nacelle 33 and a hub 34 with three rotor blades 35 are located. The nacelle 33 is also referred to as the nacelle and contains the components required to convert the rotor rotation into electrical energy, including a gearbox and a generator (not shown). According to this embodiment, the nacelle 33 also contains the controllable transformer 4 of the system 1. In other words, a transformer 4 is arranged in the nacelle 33, which includes a tap changer 2 according to the improved concept, which, however, is not shown in Figure 4 for the sake of clarity.In addition, the drive unit 6 comprising the system 1, along with the motor control unit 8, is also arranged in the nacelle 33. The control unit 7 of the system 1 is located at the base of the tower 32, within easy reach of the operator. Communication and power supply between the control unit 7 and the drive unit 6 in the nacelle 33 are ensured via two cables 11 and 12. In this embodiment or application of the system 1, the possibility of flexible spatial arrangement of the components for actuating the tap changer, the simple construction due to the elimination of the control cabinet, and the low cable complexity are also of considerable advantage to the operator of the wind turbine.

[0055] In summary, the improved concept provides a system for actuating a tap changer that enables an extremely compact design directly on the transformer, saves costs by eliminating the control cabinet on the transformer, is simple in design, in particular due to the minimized cable effort enabled by a BUS communication system, and offers a high degree of flexibility with regard to the range of applications.

[0056] REFERENCE SYMBOL

[0057] 1 system

[0058] 2 step switches

[0059] 3 control winding

[0060] 4 Transformer

[0061] 5 position sensors

[0062] 6 Drive unit

[0063] 7 Control unit

[0064] 8 Engine control

[0065] 9 Step switch head

[0066] 10 cases of 4

[0067] 11 first line

[0068] 12 second line

[0069] 13 gearboxes

[0070] 14 Engine

[0071] 15 motor drivers

[0072] 16 energy storage units

[0073] 17 Communication interface

[0074] 18 Input and output unit

[0075] 19 Signal interface

[0076] 20 Energy supply

[0077] 21 operating buildings

[0078] 22 voltage regulators

[0079] 23 higher-level control device, control room

[0080] 24 second step switch

[0081] 25 second transformer

[0082] 26 third tap changer 27 third transformer

[0083] 28 second drive unit

[0084] 29 third drive unit

[0085] 30 Drive shaft 31 Wind turbine

[0086] 32 Tower

[0087] 33 gondolas

[0088] 34 Hub

[0089] 35 Rotor blade 36 Master motor control

[0090] NJ, NJ +i , ... NN winding taps

[0091] S1 signal

Claims

CLAIMS System (1) for actuating at least one tap changer comprising a tap changer (2) for switching between winding taps NN of a control winding (3) of a transformer (4), wherein the tap changer (2) has a position sensor (5) for detecting the current position of the tap changer (2), a drive unit (6) which has a motor (14) and a gear (13), - a control unit (7) having an external signal interface (19), wherein - the drive unit (6) further comprises a motor control (8) and a motor driver (15), wherein the motor control (8) is designed to receive the current position of the tap changer (2) from the position sensor (5) and to actuate the motor (14) in such a way that a switching of the tap changer (2) from a winding tap Nj to a new winding tap N J+i is carried out, - the control unit (7) is designed to actuate the engine control (8). System (1) according to claim 1, wherein - the tap changer (2) has a tap changer head (9) by means of which the tap changer (2) can be fixed to a housing (10) of the transformer (4), - the drive unit (6) is arranged directly on the tap changer head (9). System (1) according to one of the preceding claims 1 to 2, wherein the control unit (7) is arranged spatially separated from the tap changer (2) and the transformer (4), in particular in an operating building of a substation and / or a control room. System (1) according to one of the preceding claims 1 to 3, wherein the system (1) comprises a first line (11) for internal communication between the drive unit (6) and the control unit (7). System (1) according to claim 4, wherein a bus system is used for internal communication. System (1) according to one of the preceding claims 1 to 5, wherein the system (1) comprises a second line (12) for supplying voltage to the drive unit (6). System (1) according to one of the preceding claims 1 to 6, wherein the drive unit (6) further comprises an energy storage device (16). System (1) according to one of the preceding claims 1 to 7, comprising - at least one second tap changer (24) for switching between winding taps NN of a control winding of a transformer (4, 25), wherein the at least one second tap changer (24) has a position sensor (8) for detecting the current position of the at least one second tap changer (24), - at least one second drive unit (28) which has a motor (14) and a gear (13) and is assigned to the second step switch (24), wherein - the at least one second drive unit (28) further comprises a motor controller (8) and a motor driver (15), wherein the motor controller (8) is designed to receive the current position of the at least one second step switch (24) from the position sensor (8) and to actuate the motor (14) in such a way that a switching of the at least one second step switch (24) from a winding tap Nj to a new winding tap N J+i is carried out, whereby - the control unit (7) is designed to actuate each motor control (8) of the system (1).

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