Method for switching an on-load tap changer by means of a drive system and drive system for an on-load tap changer

Abstract

The invention relates to a method for switching an on-load tap changer (8) by means of a drive system (3). The drive system (3) comprises at least one motor (12), a control device (2) and an encoder system (13), the motor acting on a drive shaft (16), the encoder system being coupled directly or indirectly to the drive shaft (16). Via the control device (2) a certain driving characteristic (22) can be selected, so that the drive system (3) of the on-load tap changer (8) carries out a switching from a tap (N J ) to the next tap (N J+1 ) or (N J‑1 ) by means of one driving characteristic (22) or several driving characteristics (22).

Description

TECHNICAL FIELD

[0001] The invention relates to a method for switching an on-load tap changer by means of a drive system. The drive system comprises at least one motor, which acts onto a drive shaft. A control device and an encoder system are provided, which are coupled directly or indirectly to the drive shaft.

[0002] The invention also relates to a drive system for an on-load tap changer, which is used to carry out the method according to the invention. BACKGROUND

[0003] A drive device for an on-load tap changer is known, for example, from the German utility model DE 20 2010 011 521 U1. In this on-load tap changer drive device, a motor is provided, which is connected to the corresponding on-load tap changer via a connecting rod. The motor is switched on or off by means of a hard-wired manipulation, i.e. by manipulating a motor protector. The on-load tap changer is then manipulated via a drive shaft. Once assembled, no changes can be made on the drive device anymore. The drive device thus becomes inflexible and unadaptable. The simplest adaptations require complex retrofits.

[0004] On-load tap changers are usually used to regulate the voltage in different transformers. For manipulating the on-load tap changer, a drive system is used. Here, a motor provided on the transformer housing is connected to the on-load tap changer via a connecting rod. The motor is supplied with energy by manipulating an electromechanical protector. Depending on the wiring, the motor is manipulated in such a way that its drive shaft is rotated in one direction or the other. This type of manipulation is inflexible and thus unadaptable. SUMMARY

[0005] It is therefore an object of the present invention to describe an improved concept for driving an on-load tap changer, by which the operational flexibility and the safety when switching the taps of the on-load tap changer are improved.

[0006] This object is solved by a method for switching an on-load tap changer by means of a drive system.

[0007] It is also an object of the present invention to describe a drive system for an on-load tap changer, by which the operational flexibility and the safety when switching the taps of the on-load tap changer are improved.

[0008] This object is solved by a drive system for an on-load tap changer.

[0009] For implementing the method for switching an on-load tap changer according to the application, a drive system is provided. The drive system comprises at least one motor, which acts on a drive shaft. A control device is in communication connection with an encoder system, which is coupled directly or indirectly to the drive shaft. The method is characterized by the following steps: First, a signal for switching the on-load tap changer is received by the control device. In a next step, it is determined by means of the control device whether a switch to the current tap is to be made from an upward direction or from a downward direction. Then, it is determined whether a switch to the next tap is to be made in the upward direction or in the downward direction. In a subsequent step, one of a plurality of driving characteristics of the drive system for the on-load tap changer is selected by means of the determination in the previous step. Then, the switching is carried out by means of the selected driving characteristic or characteristics. In a final step, the switching is carried out and monitored by means of the drive system in accordance with the selected driving characteristic.

[0010] According to a preferred embodiment of the application, a plurality of driving characteristics can be stored in the control device. The control device can be equipped with a memory for storing the driving characteristics.

[0011] The switching operation in an on-load tap changer in which a plurality of driving characteristics are applied has the advantage that a gentle switching can be achieved, since the switching can be adapted to the mechanical characteristics of the on-load tap changer. As a result, the mechanical components can also be protected. In addition, the switching can be designed flexibly. Furthermore, particularities in the construction, such as an unloaded run in the selector of the on-load tap changer, are also taken into account by means of the corresponding driving characteristics.

[0012] According to the application, a first possible driving characteristic can describe a switching of the on-load tap changer in the upward direction. Here, it is determined before the switching whether a switch is to be made from a tap to the next higher tap. In the current switching, it is determined whether a switch is to be made from the next higher tap to a subsequent higher tap.

[0013] According to the application, a second possible driving characteristic can describe a switching of the on-load tap changer in the downward direction. Here, it is determined before the switching whether a switch is to be made from a tap to the next lower tap. In the current switching, it is checked whether a switch is to be made from the next lower tap to a lower tap.

[0014] In both cases, the drive shaft of the on-load tap changer is rotated by an integer multiple of 180 degrees by means of the selected driving characteristic. Preferably, the drive shaft of the on-load tap changer is rotated by 180 degrees or also by 360 degrees. It can also be that the drive shaft can also be rotated by more than 360 degrees. Depending on the type of switch and the drive system, the drive shaft is rotated by the corresponding value.

[0015] According to a possible embodiment of the application, a third possible driving characteristic can describe a switching of the on-load tap changer in the upward direction. Here, it is checked before the switching whether in the previous switching a tap was switched to the next lower tap. Then, in the current switching, from the current lower tap again to a higher tap is switched, taking into account the no-load run of the on-load tap changer.

[0016] According to a possible embodiment, a fourth possible driving characteristic can describe a switching of the on-load tap changer in the downward direction. Before the switching, it is checked whether in the previous switching a tap was switched to the next higher tap. Then, in the current switching, from the higher tap again to a lower tap is switched, taking into account the no-load run of the on-load tap changer.

[0017] The driving characteristics are designed in such a way that the driving characteristics rotate the drive shaft by an integer multiple of 180 degrees. For this purpose, further angle values are obtained, which take into account the no-load run of the transmission. Depending on the switching type and the drive system, the drive shaft is rotated by the corresponding value and superimposed with the value of the no-load run.

[0018] According to another possible embodiment, a fifth driving characteristic can be designed in such a way that the driving characteristic from a tap to the next first higher tap or to the next first lower tap to be moved closer is combined with at least one further driving characteristic. As a result of the combination, at least one further next higher tap or at least one further next lower tap can be moved closer. The assignment of the driving characteristics takes place before the drive system is put into operation.

[0019] The current tap is determined by means of the control device. The determined current tap is used to select the necessary driving characteristic or the necessary driving characteristics. Contrary to the general inventive concept, not only the direction is used to select the driving characteristic, but also the position of the on-load tap changer, i.e. the tap, is used to select the driving characteristic.

[0020] Each of the driving characteristics consists of two variables and can be plotted as an n-th polynomial function in a two-dimensional Cardioid coordinate system.

[0021] The stored driving characteristics can be recalled by the control device of the drive system or by the control unit.

[0022] The drive system for an on-load tap changer according to the application comprises a drive shaft, which connects the drive system with the on-load tap changer, for implementing the method. A motor is used to drive the drive shaft. A feedback system is provided for determining the position of the drive shaft. A feedback signal is generated on the basis of the determined position. A control device is provided for acting on the operation of the motor in accordance with the selected driving characteristic and the feedback signal.

[0023] The control device comprises a control unit and a power unit. The power unit is used to energize the motor. The at least one driving characteristic is stored in a memory of the power unit. The control unit selects a driving characteristic and the power unit acts on the motor in correspondence with the driving characteristic.

[0024] The improved solution with driving characteristics is based on the idea that a driving characteristic is selected for the drive system before the on-load tap changer is switched or manipulated, with which the switching is carried out. Here, it must first be determined in which position (tap) the on-load tap changer was before and in which position (tap) it should be switched. Therefore, the corresponding driving characteristic for the next switching is selected for the drive system.

[0025] It can additionally also be determined in which position the on-load tap changer is in a switching process, i.e. in which position or tap position the on-load tap changer is. The supplement of the actual position to the switching direction can also be used to select the driving characteristic in special cases. By selecting the driving characteristic tailored to the specific switching step or switching, the safety of the overall system is improved. Furthermore, mechanical components are not necessary. Additionally, the speed of the switching can be optimized, even increased, if possible.

[0026] The knowledge of the switching direction (past and future) and the current tap position enables the selection of a driving characteristic that is optimally designed for the next switching. Mechanical no-load running, clearances and special cases in the manipulation process are thus taken into account individually.

[0027] According to at least one embodiment of the application, the switching signal is triggered by a voltage regulator required for regulating the step transformer, a manual input or by an external signal.

[0028] According to at least one embodiment of the application, the control device has a memory in which each driving characteristic and the assignment of the driving characteristic to the switching step and the current tap position are stored.

[0029] According to at least one embodiment of the application, the control device has a control unit and a power unit, in the memory of the control unit the assignment of the driving characteristic to the switching step and the current tap position are stored and in the memory of the power unit the driving characteristics are stored.

[0030] The drive system according to the refinement enables targeted, i.e. in accordance with a previously selected driving characteristic, driving of the drive shaft. The driving characteristic does not only predefine a speed or a torque. The driving characteristic predefines at which point in time or at which position of the drive shaft, what torque or what speed is to be implemented on the drive shaft. By using such a driving characteristic, it is possible to influence the targeted division of the switching over. The current position of the drive shaft, i.e. the actual value, is compared to the driving characteristic, i.e. the target value, via a feedback signal. As a result, the system becomes flexible and reliable.

[0031] The term "position of the drive shaft" comprises measurement variables from which the position of the drive shaft, possibly within a tolerance range, can be unambiguously determined.

[0032] According to at least one embodiment, the drive system is used to drive a shaft of a switch, of a load tap changer or of a corresponding component of a load tap changer. As a result, the load tap changer is prompted to implement one or more operations, such as a switching between two winding taps of a running part or a part of said switching, such as a load switching, a selector maneuver or a preselector maneuver.

[0033] According to at least one embodiment, the drive shaft is connected, directly or indirectly, in particular via one or more gear mechanisms, to a load tap changer, in particular to a shaft of a load tap changer.

[0034] According to at least one embodiment, the drive shaft is connected, directly or indirectly, in particular via one or more gear mechanisms, to a load tap changer, in particular to a shaft of a load tap changer.

[0035] According to at least one embodiment, the drive shaft is connected, directly or indirectly, in particular via one or more gear mechanisms, to a motor, in particular to a motor shaft of a motor.

[0036] According to at least one embodiment, the position, in particular the absolute position, of the motor shaft corresponds to the position, in particular the absolute position, of the drive shaft. That is, the position of the drive shaft can be unambiguously inferred from the position of the motor shaft, possibly within a tolerance range.

[0037] According to at least one embodiment, the action comprises controlling, regulating, braking, accelerating or stopping the motor. The regulation can comprise, for example, a position regulation, a speed regulation, an acceleration regulation or a torque regulation. At least in the case of such a regulation, the drive system can be said to be a servo drive system.

[0038] According to at least one embodiment, the drive system comprises a monitoring unit which is designed to monitor, by means of a feedback signal, one or more operations of the switch. The monitoring in particular comprises monitoring whether the individual operations or parts thereof of the operations are implemented as specified, in particular within a predefined time window.

[0039] According to at least one embodiment, the control device comprises a control unit and a function for controlled or regulated energization of the motor. The control unit is designed to actuate the function. At least one driving characteristic is stored in the function, which driving characteristic consists of two variables and can be plotted as an n-th order polynomial function in a two-dimensional Cardioid coordinate system.

[0040] According to at least one embodiment, the function is designed as an inverter or a servo inverter or as an equivalent electronic, in particular purely electronic, unit for driving the motor.

[0041] According to different embodiments, the control device comprises a feedback system completely or partially.

[0042] The absolute position of the drive shaft can be compared, for example, by the control device. In the event of a significant deviation, the control device can issue an error message or introduce safety measures.

[0043] According to at least one embodiment, the feedback system is designed to determine the rotor position of the motor and to determine the value for the position of the drive shaft from the rotor position.

[0044] According to at least one embodiment, the rotor position relates to the angular range in which the rotor of the motor is located, if necessary in combination with the number of complete rotations of the rotor.

[0045] According to the design of the rotor, in particular the number of pole pairs, the position or absolute position of the motor shaft can thus be determined precisely up to at least 180°, for example, by the control device. The precision that can thus be achieved for the position of the drive shaft is significantly higher by virtue of the reduction by means of one or more gear mechanisms. Here, the analysis by the control device corresponds to a virtual encoder function to a certain extent. Thus, even in the event of a complete failure of the absolute value encoder of the feedback system, at least one emergency operation and / or the on-load tap changer can be maintained in a safe position.

[0046] According to at least one embodiment, the feedback system comprises an absolute value encoder, which is designed and set up to detect the absolute position of the drive shaft or of a further shaft connected to the drive shaft, to generate at least one output signal on the basis of the detected position. The feedback system is designed to determine the value for the position of the drive shaft by means of the at least one output signal.

[0047] According to at least one embodiment, the absolute value encoder is fixed directly or indirectly on the motor shaft, the drive shaft or a shaft coupled thereto.

[0048] According to at least one embodiment, the absolute value encoder comprises a multi-turn encoder or a single-turn encoder.

[0049] According to at least one embodiment, the absolute value encoder is designed to detect the position of the drive shaft or the position of the further shaft by means of a scanning method.

[0050] According to at least one embodiment, the scanning method comprises an optical, magnetic, capacitive, resistive or inductive scanning method.

[0051] According to at least one embodiment, the feedback system comprises a combination of an absolute value encoder and auxiliary contacts, which are designed and set up in combination to detect the absolute position of the drive shaft or of a further shaft connected to the drive shaft and to generate at least one output signal on the basis of the detected position. The feedback system is designed to derive a value for the position of the drive shaft by means of the at least one output signal.

[0052] According to at least one embodiment, the absolute value encoder and the auxiliary contacts are fixed directly or indirectly on the motor shaft, the drive shaft or a shaft coupled thereto.

[0053] According to at least one embodiment, the absolute value encoder is designed as a single-turn encoder or as an incremental encoder or as a virtual encoder. The auxiliary contacts are designed as at least one microswitch or resolver or sine / cosine encoder.

[0054] According to at least one embodiment, the absolute value encoder and the auxiliary contacts are designed to detect the position of the drive shaft or the position of the further shaft by means of a scanning method.

[0055] According to at least one embodiment, the scanning method comprises an optical, magnetic, capacitive, resistive or inductive scanning method.

[0056] According to at least one embodiment, the driving behavior can be composed of two variables and can be plotted as an n-th polynomial function in a two-dimensional Cardioid coordinate system.

[0057] According to at least one embodiment, the variables are direct or indirect variables of the drive system, such as time, angle of rotation of the drive shaft, current, voltage, speed, torque or acceleration.

[0058] According to at least one embodiment, one variable can be represented by a corresponding axis of the coordinate system.

[0059] According to at least one embodiment, the control device can act on a second motor.

[0060] According to at least one embodiment, the control device can have a second functional element, which acts on a second motor.

[0061] According to at least one embodiment, the control device acts on the second motor in such a way that this second motor runs through the travel characteristic of the actual value of the feedback system of the first motor.

[0062] According to at least one embodiment, the on-load tap changer has a load transfer switch and a selector and a double commutator or a commutator or a preselector. BRIEF DESCRIPTION OF DRAWINGS

[0063] The application and its advantages will be described in detail below with the aid of the schematic drawings. In the drawings:

[0064] Figure 1 A drive device for an on-load tap changer is shown, with which a changeover between different taps of a transformer can be carried out;

[0065] Figure 2 A method flow for operating an on-load tap changer according to the improvement is shown;

[0066] Figure 3 A schematic diagram of an embodiment of an on-load tap changer according to the improvement is shown, which has a drive system;

[0067] Figure 4a A travel characteristic for a drive system according to the application is shown, which shows the angle of rotation of the drive shaft as a function of time;

[0068] Figure 4b A travel characteristic for a drive system according to the application is shown, which shows the torque as a function of the angle of rotation of the drive shaft. DETAILED DESCRIPTION

[0069] The same reference signs are used for identical or identically acting elements of the application. In addition, for the sake of clarity, only the reference signs necessary for describing the respective drawing are shown in the individual drawings. The drawings show only embodiments of the application, however the application is not limited to the embodiments shown.

[0070] Figure 1 An on-load tap changer 8 is shown with the taps N1, N2,... N N Cooperating schematic configuration. For driving the selector 18 and the load transfer switch 17, a motor 12 is provided, which acts via a transmission mechanism 15 on the selector 18 and the load transfer switch 17, i.e. on the on-load tap changer 8. Via a motor shaft 4 and a drive shaft 16, the motor 12 acts on the on-load tap changer 8 in order to run in the upward direction N + By the taps N1, N2,... N J Changeover to the next higher tap N J+1 upward or in the downward direction N- by tap N J to the next lower tap N J-1 .

[0071] Figure 2 A method flow for the manipulation of the on-load tap changer 8 by means of the drive system 3 according to the application is shown (see Figure 3 ). In a first step 40, a signal for "switching" is first given on the control device 2. This signal is generated by a voltage regulator, a monitoring system or by manual input (not shown here). That is to say, the on-load tap changer 8 must be manipulated, for example, in order to adapt the voltage of the transformer 9 (see Figure 1 ) accordingly. However, a calibration method during maintenance, i.e. manipulation of the on-load tap changer 8 in a service operation, is also conceivable. In a next step 50, it is then checked in the control device 2: in which direction (upward direction N + or downward direction N - ) the switching, i.e. the switching of the tap N1, N2... N N or in other words the tap position, to the transformer 9 is to be performed. It is also checked: from which direction (upward direction N + or downward direction N - ), i.e. which position or in other words tap position, the on-load tap changer 8 was previously switched into the current position (tap N J ). The order of these steps is arbitrary. In a next step 60, the driving profile 22 corresponding to the result is selected, with which the on-load tap changer 8 is manipulated in a next step 70.

[0072] This simplified method allows the manipulation of simple on-load tap changers 8 with only two or four driving profiles 22.

[0073] Here, the first possible driving profile 22 describes the switching of the on-load tap changer 8 in the upward direction N + when starting without switching in the downward direction N - . In other words, a switching is performed before the switching from tap N J to tap N J+1 and now a switching from tap N J+1 to tap N J+2 should be performed. Thereby, a switching in the same direction, i.e. in the upward direction N + , is performed. Here, the drive shaft 6 of the on-load tap changer 8 is preferably rotated by 180 degrees or also by 360 degrees. However, the drive shaft 16 can also be rotated by more than 360 degrees.

[0074] The second possible driving profile 22 describes the switching of the on-load tap changer 8 in the downward direction N - when starting without switching in the opposite switching direction.Switching. In other words, a change from tap N J+2 to tap N J+1 above is made and now should be changed to tap N J above. Thereby, the change is made in the same direction. Here, the drive shaft 16 is preferably rotated by 180 degrees or also by 360 degrees. However, the drive shaft 16 can also be rotated by more than 360 degrees.

[0075] When, for example, a mechanical no-load run (not shown) is established in the on-load tap changer 8, these no-load runs must be taken into account at the switching when changing from the downward direction N - to the upward direction N + or vice versa, i.e. from a first change direction to a second change direction opposite to the first change direction. These no-load runs are an integral part of the mechanical system of the on-load tap changer 8, for example due to the construction of a back-pressure device in the spring accumulator or selector 18. For this purpose, third and fourth driving characteristics 22 are stored in the control device 2. This driving characteristic 22 has characteristics which differ from those of the first or second driving characteristics 22. For example, the drive shaft 16 is rotated by an angle in the third and fourth driving characteristics 22 which exceeds the angle of rotation in the first and second driving characteristics 22 of the previous change. In the switching which is carried out with the drive shaft rotated by 180 degrees, the values which take the no-load runs into account must be included. The drive system 3 then rotates the drive shaft 16 by more than 180 degrees. Here, the share of the no-load run is added to the basic value necessary for carrying out the change. If the subsequent change should also be made in the same direction (downward direction N - or upward direction N + ), the respective driving characteristic 22 is used.

[0076] The first and second or third and fourth driving characteristics 22 can be designed identically apart from their sign. In principle, the driving characteristics 22 can differ from one another in every variable. The driving characteristics can, for example, be carried out faster or slower. The driving characteristics can be partly identical to one another, however supplemented by another section.

[0077] In summary, the driving characteristics 22 are selected by means of the change direction (downward direction N - or upward direction N + ) of the previous change and the change direction (downward direction N - or upward direction N + ) of the next change.

[0078] However, in a more complex on-load tap changer 8, the actual position or actual tap position of the tap must also be taken into account in which the on-load tap changer 8 is. Then, in addition, it is checked in the control device 2 in a step 50 in which position or tap position of the on-load tap changer 8 the tap is currently in. It is also checked in which position or on which tap it should be switched to and from which position or from which tap it is switched to the current position. The sequence of these steps is arbitrary. In a next step 60, the driving characteristic 22 corresponding to the result is selected, with which the on-load tap changer 8 is operated in a subsequent step 70.

[0079] Here, a fifth driving characteristic 22 can be provided. This fifth driving characteristic is necessary in the so-called passage position of the on-load tap changer 8 or in an on-load tap changer 8 of asymmetric design. Here, the control device 2 recognizes that the next switching is the so-called passage position. This means that the first tap N J+1 or N J-1 which is to be approached with the driving characteristic 22 should not be stopped. Only the tap N J+X or N J-X (X is a value equal to or greater than 2) can be reached by at least one further driving characteristic 22. The recognition of such a switching is achieved in that the switching steps from one certain tap N J to another certain tap N J+X or tap N J-X or in the switching direction (downward direction N - or upward direction N + ) are assigned to at least one further driving characteristic 22. This assignment is made before the drive system 3 is put into operation and is stored in the memory 50 or in the control unit 10 of the control device 2. This driving characteristic 22 also differs from the first and second driving characteristics 22 in its characteristics. In the so-called passage position, the drive shaft 16 must be rotated many times more than in a normal switching (from the current tap N J to a tap N J+1 or N J-1 ) of the on-load tap changer 8. This driving characteristic 22 is configured for a certain switching between two certain taps N J and tap N J+X or N J and N J-X .

[0080] In principle, it is allowed by the combination of the determination of the switching direction (past and future) with the actual position or actual tap position to exactly select and implement a driving characteristic 22 tailored to this switching.

[0081] Figure 3 An exemplary embodiment of a drive system 3 for a load tap changer 8 is shown. The drive system 3 is connected with the load tap changer 8 via a drive shaft 6. The drive system 3 comprises a motor 12 which can drive the drive shaft 16 via a motor shaft 14 and optionally via a transmission 15. The control device 2 of the drive system 3 comprises a power piece 11 which for example comprises an inverter (not shown) for controlled or regulated energizing of the motor 2. The control unit 10 is connected for example via a bus 19 for operating the power piece 11. The drive system 3 has an encoder system 13 which serves as a feedback system 4 or is part of the feedback system 4 and is connected with the power piece 11 (not shown). Furthermore, the encoder system 13 is coupled directly or indirectly with the drive shaft 16 (not shown).

[0082] The encoder system 13 is provided for detecting at least one first value for the position, in particular the angular position, for example the absolute angular position, of the drive shaft 16. For this purpose, the encoder system 13 can for example comprise an absolute value encoder, in particular a multi-turn absolute value encoder, which is fixed on the drive shaft 16, the motor shaft 14 or on another shaft whose position is unambiguously linked to the absolute position of the drive shaft 16. The position of the drive shaft 16 can be unambiguously determined from the position of the motor shaft 14, for example via the transmission ratio of the transmission 15.

[0083] The feedback system 4 is provided for detecting a value for the position of the drive shaft 16.

[0084] The control device 2, in particular the control unit 11 and / or the power piece 12, is provided for controlling or regulating the motor 12 depending on a feedback signal which is generated by the feedback system 4 on the basis of the value.

[0085] The power piece 11 has a memory 5 in which a driving characteristic 22 is stored. The encoder system 13 which serves as the feedback system 4 reports to the power piece 11 the position of the drive shaft 16 and thus monitors whether the drive shaft 16 correctly executes the driving characteristic 22 or in other words follows the pre-set parameters.

[0086] A plurality of driving characteristics 22 is stored in the power piece 11. Via the control unit 11 one of the driving characteristics 22 is selected by means of a selection signal 20. Figure 1 The method shown selects one of the driving characteristics 22.

[0087] Figure 4a and Figure 4b Possible driving characteristics 22 of the motor 12 for the switching process of the load tap changer 8 are shown. Here, the driving characteristics 22 are shown by way of example as n-th order polynomial functions with two variables which can be plotted into a two-dimensional Cardioid coordinate system 21. In the shown example, the driving characteristics 22 are shown as straight lines in the Cardioid coordinate system 21. Figure 4aIn the driving characteristic 22 shown in Fig. 2, the time t, i.e. how long the drive shaft 16 is operated by the motor 12, is plotted on the X-axis 24. The rotational angle ω of the drive shaft 16 is plotted on the Y-axis 25. In Figure 4a The variables plotted on the axes 24, 25 are examples only and should not be understood as a restriction of the application. The variables plotted on the X-axis 24 and the Y-axis 25 can be direct variables or indirect variables of the drive system 3. Direct variables can be, for example, the time t, the rotational angle ω of the drive shaft 16, the current or the voltage. Indirect variables can be the speed, the torque, the acceleration or similar variables.

[0088] Figure 4b A possible driving characteristic 22 for the switching process of the switch 1 is shown for the motor 12. Here, an indirect variable of the torque M(t) is plotted as a function of the rotational angle ω and is shown as a polynomial function of the n-th order. In Figure 4b In the driving characteristic 22 shown in Fig. 3, the rotational angle ω is plotted on the X-axis 24. The torque M(t) acting on the drive shaft 16 is plotted on the Y-axis 25.

[0089] The driving characteristic 22 prescribes a setpoint value which the drive shaft 16 should execute. In the execution of the driving characteristic 22, the actual value detected via the feedback system 4 can deviate from the setpoint value. Depending on the possible deviation of the actual value from the setpoint value, the action on the motor can be aborted or continued. The deviation can be set manually or be determined by means of a learning process.

[0090] List of reference signs

[0091] 2 control device

[0092] 3 drive system

[0093] 4 feedback system

[0094] 5 memory

[0095] 8 on-load tap changer

[0096] 9 transformer

[0097] 10 control unit

[0098] 11 power piece

[0099] 12 motor

[0100] 13 encoder system

[0101] 14 motor shaft

[0102] 15 transmission

[0103] 16 drive shaft

[0104] 17 load switching switch

[0105] 18 selector

[0106] 19 bus

[0107] 20 regulating winding

[0108] 21 cardiel coordinate system

[0109] 22 running characteristic

[0110] 24 X axis

[0111] 25 Y axis

[0112] 40 step

[0113] 50 step

[0114] 60 step

[0115] 70 step

[0116] N+ upward direction

[0117] N- downward direction

[0118] N1, N2,..., NN tap

[0119] T time

[0120] M(t) torque

[0121] ω rotation angle

Claims

1. A method for switching an on-load tap changer (8) by means of a drive system (3), said drive system (3) comprising at least one motor (12), a control device (2), and an encoder system (13), said motor acting on a drive shaft (16), said encoder system being directly or indirectly coupled to said drive shaft (16), characterized in that, The method includes the following steps: - In step (40), the control device (2) receives a signal for switching the on-load tap changer (8); - In step (50), it is determined by means of the control device (2): from the upward direction (N) + ) or from the downward direction (N) - ) Convert to the current tap (N) J On, and along the upward direction (N) + ) or along the downward direction (N) - Switch to the next tap (N) J+1 N J-1 )superior; - In step (60), one of the multiple driving characteristics (22) of the drive system (3) for the on-load tap changer (8) is selected by means of the determination in step (50), and the switching is performed by means of the driving characteristic; and - In step (70), the switching is implemented and monitored by means of the drive system (3) according to the selected driving characteristics (22).

2. The method according to claim 1, wherein, Multiple driving characteristics (22) are stored in the control device (2).

3. The method according to claim 1 or 2, wherein, The first possible driving characteristic (22) describes the on-load tap changer (8) in the upward direction (N) + Before switching, it is determined whether the tap (N) has already been switched. J Switch to the next higher tap (N) J+1 On, and in the current switch from the next higher tap (N) J+1 ) to a higher tap (N) J+2 )superior.

4. The method according to claim 1 or 2, wherein, The second possible driving characteristic (22) describes the on-load tap changer (8) in the downward direction (N) - Before switching, it is determined whether the tap (N) has already been switched. J+2 Switch to the next lower tap (N) J+1 On, and in the current switch, check: whether from the next lower tap (N) J+1 Switch to a lower tap (N) J )superior.

5. The method according to claim 3, wherein, The driving characteristics (22) cause the drive shaft (16) to rotate by an integer multiple of 180 degrees.

6. The method according to claim 1, wherein, The third possible driving characteristic (22) describes the on-load tap changer (8) in the upward direction (N) + Before switching, check whether the tap (N) has already been switched. J+1 Switch to the next lower tap (N) J On the current switch, check whether the tap (N) is switched on again while considering the no-load operation of the on-load tap changer (8). J Switch to the next higher tap (N) J+1 )superior.

7. The method according to claim 1, wherein, The fourth possible driving characteristic (22) describes the on-load tap changer (8) in the downward direction (N) - Before switching, check whether the tap (N) has already been switched. J+1 Switch to the next higher tap (N) J+2 On the current switch, check whether the tap (N) is switched on again while considering the no-load operation of the on-load tap changer (8). J+2 Switch to the next lower tap (N) J+1 )superior.

8. The method according to claim 6 or 7, wherein, The driving characteristic (22) causes the drive shaft (16) to rotate by an integer multiple of 180 degrees plus another angle value to take into account the no-load operation of the transmission mechanism (15) of the on-load tap changer (8).

9. The method according to claim 1, wherein, The fifth driving characteristic (22) is designed so that the tap (N) will be used to drive the vehicle. J ) to move to the next higher tap (N) J+1 ) or the next first lower tap (N) J-1 The driving characteristic (22) of the vehicle is combined with at least one other driving characteristic (22) to move closer to at least one other next higher tap (N). J+X ) or at least one other next lower tap (N) J-X The driving characteristics (22) are allocated before the drive system (3) is put into operation.

10. The method according to claim 1 or 2, wherein, The current tap (N) is determined by means of the control device (2). J ), and the current tap is used to select the required driving characteristics (22).

11. The method according to claim 1 or 2, wherein, Each driving characteristic (22) consists of two variables and can be plotted as an nth-degree polynomial function in a two-dimensional Cartier coordinate system (21).

12. The method according to claim 2, wherein, The stored driving characteristics (22) are retrieved by the control device (2) or the power unit (11) of the drive system (3).

13. A drive system (3) for an on-load tap changer (8), said drive system for implementing the method according to any one of claims 1 to 12, said drive system comprising: - Drive shaft (16), which connects the drive system (3) to the on-load tap changer (8); - A motor (12) for driving the drive shaft (16); - Feedback system (4), the feedback system being configured to determine the position of the drive shaft (16) and generate a feedback signal based on that position; and - Control device (2), the control device is configured to act on the operation of the motor (12) according to the selected driving characteristics (22) and the feedback signal.

14. The drive system (3) according to claim 13, wherein, The control device (2) includes a control unit (10) and a power unit (11), the power unit (11) is used to supply power to the motor (12), and the at least one driving characteristic (22) is stored in the memory (5) of the power unit (11), the control unit (10) selects a driving characteristic (22), and the power unit (11) acts on the motor (12) corresponding to the driving characteristic (22).

15. The drive system (3) according to claim 13 or 14, wherein, The feedback system (4) includes an encoder system (13) configured and set up for detecting the position of at least the drive shaft (16).

16. The drive system (3) according to claim 15, wherein, The encoder system (13) includes an absolute encoder and an auxiliary contact, which are configured and set together for detecting the absolute position of at least the drive shaft (16).

17. The drive system (3) according to claim 16, wherein, The absolute encoder and the auxiliary contact are directly or indirectly fixed to the motor shaft (14), the drive shaft (16), or another shaft coupled to the drive shaft.

18. The drive system (3) according to claim 16, wherein, The absolute encoder is designed as a single-turn encoder, an incremental encoder, or a virtual encoder, and the contact is designed as at least one microswitch, a resolver, or a sine / cosine encoder.

19. The drive system (3) according to claim 17, wherein, The absolute encoder and the auxiliary contact are configured to detect the position of the drive shaft (16) or the position of the other shaft by means of scanning.

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