METHOD FOR PERFORMING A SWITCHING OF AT LEAST TWO SWITCHING ELEMENTS OF AN OPERATING EQUIPMENT AND DRIVE SYSTEM FOR AT LEAST TWO SWITCHING ELEMENTS IN AN OPERATING EQUIPMENT

Description

[0001] The invention relates to a method for carrying out a switching of at least two switching means in an operating means.

[0002] Furthermore, the invention relates to a drive system for at least two switching means of an operating means.

[0003] Document WO 2012 / 135209 A1 discloses a method according to the preamble of claim 1.

[0004] German patent application DE 10 2014 110 732 A1 discloses an on-load tap-changer with a motor drive for switching between the winding taps of a tapped transformer. A drive shaft is driven by the motor drive. The rotary movement of the motor drive is provided via two switchable coupling devices, a first drive shaft associated with the selector and a second drive shaft associated with the load diverter switch. The selector and the load diverter switch can be designed to be switchable relative to one another, independent of the initial rotary movement of the motor drive.

[0005] Voltage regulation in power transmission and distribution networks requires the installation of different types of switches in transformers. Transformers typically incorporate on-load tap-changers, consisting of a diverter switch and a selector, operated by a common drive. Both the operation and design of the diverter switch are intrinsically linked to the selector. Simply adapting the operation of either the selector or the diverter switch is not possible.

[0006] It is therefore an object of the present invention to provide a method for carrying out a switching of switching means of an operating means, by which the safety and reliability of the switching means and the operating means are increased.

[0007] This object is achieved by a method for carrying out a switching of a first switching means or at least a second switching means of an operating means, which comprises the features of claim 1.

[0008] A further object of the invention is to provide a drive system for at least two switching means of an operating means, which increases the safety and reliability of the switching means and the operating means during the switching process.

[0009] Equipment comprising the features of claim 7.

[0010] The method according to the invention is characterized in that a switching of a first switching means or at least one second switching means is carried out in an operating means. For this purpose, a control unit receives a switching signal. The control unit is communicatively connected to a power unit that is connected to the motors for driving the switching means. The first switching means for switching is selected by means of the control unit. At least one parameter of a first switching means or of at least one second switching means is queried by the control unit. A locking condition is checked for the selected first switching means or for the at least second switching means based on the at least one queried parameter. The switching is carried out by means of the selected first switching means or the selected second switching means if the corresponding locking condition is met.To implement the switching, a power unit is controlled by the control unit. This allows the selected first switching device or the selected at least second switching device to be actuated. Depending on the implementation of the switching, the first switching device is actuated via a drive shaft coupled to the first motor. The at least second switching device is actuated via a drive shaft of a second motor. Furthermore, the selected first switching device and the selected at least second switching device can be actuated.

[0011] The method according to the invention is based on the idea that an operating device, for example a transformer, comprises at least one on-load tap-changer, which is divided into its individual switching devices or switching device groups. These individual switching devices can be driven separately and individually by their own motors. Before one of the switching devices in the operating device is actuated or switched and performs a switchover, an interlocking condition is checked. For this check, at least one parameter is queried. If the interlocking condition is met by the queried parameter, the switchover occurs.

[0012] The at least one parameter of the first switching means and of the at least second switching means can be determined, for example, using a feedback system. Thus, one feedback system is assigned to the first switching means, and another feedback system is assigned to the at least second switching means.

[0013] For an operating device, particularly a transformer, with two switching devices, particularly a diverter switch and a selector, a control unit, for example, checks the position of the selector. The parameter for the locking condition to be checked is therefore the position of the selector, which is determined using the selector's feedback system.

[0014] With each feedback system assigned to each of the existing switching devices, at least one parameter for switching the switching device can be determined. The parameter determined by the feedback system is a position of the respective switching device. The parameter determined by the feedback system can also indicate whether the switching device required for the selected or specific switching is currently being actuated. If this is the case, the corresponding switching device cannot be actuated. Furthermore, the parameter can be a movement state that indicates whether the switching device is currently being actuated.

[0015] The feedback system can be designed in a variety of ways. The feedback system can be an encoder, a multiturn encoder, a singleturn encoder, a resolver, a switch, a microswitch, a sensor, a contact, etc. It is obvious to a person skilled in the art that this list of possible feedback system designs is not exhaustive.

[0016] The parameters to be queried can be determined arbitrarily and can be of any type. The parameters can be feedback systems on the motors of the respective switching devices, simple safety switches on the equipment, or even customer-specific release buttons. Furthermore, the feedback system could be part of the control device that counts the switching or stops a time for a switchover and from this provides the one parameter to be queried for an interlocking condition. Likewise, a parameter can also be obtained from a temperature sensor that is assigned, for example, to each of the switching devices. Safety switches that determine the interlock of the control cabinets assigned to the equipment can also contribute to a parameter. If, for example, a safety switch were to indicate an open control cabinet, the switchover must not be carried out.It is also obvious to a person skilled in the art that the list of possible parameters that contribute to determining the locking condition is not exhaustive.

[0017] The feedback system is used to determine the parameter required to check a locking condition. The parameter depends on the feedback system.

[0018] Depending on the design, the parameter is a value, a range of values, a simple signal, etc.

[0019] According to a possible embodiment of the invention, switching means can be combined to form a switching means group.

[0020] According to one possible embodiment of the invention, the queried parameters of the first switching device and the at least second switching device can be evaluated and combined in the control unit. Based on the results of the evaluation or combination, the control unit can control the first switching device, or the first switching device and the at least second switching device, as needed.

[0021] According to one possible embodiment of the invention, a plurality of individual operating devices can be provided. Each of the plurality of operating devices is assigned a power unit, each of which can be controlled by a common control unit. The first switching devices of the plurality of operating devices are combined into a first switching device group. The at least second switching devices of the plurality of operating devices are combined into at least a second switching device group.

[0022] According to the invention, a drive system for at least two switching means of an operating device is disclosed. The drive system comprises a first switching means which is connected to a first motor via a drive shaft. The drive system further comprises at least one second switching means which is connected to at least one second motor via a drive shaft. A feedback system is assigned to the first motor and to each at least second motor in order to determine at least one parameter of the switching means. A control unit, which is communicatively connected to a power unit in order to actuate the first switching means with the first motor and the at least second switching means with the at least second motor, determines by which of the at least one determined parameter the locking conditions are met.

[0023] According to a possible embodiment of the invention, the at least second switching means comprise a second switching means connected to a second motor and a third switching means connected to a third motor.

[0024] The advantage is that each switching device is assigned its own motor, which, compared to the state of the art, enables safe and reliable drive of the switching devices. Driving all switching devices with a single motor, which is coupled to the switching devices via linkages and couplings, is no longer necessary. This also enables digital monitoring of the drive system for the operating devices.

[0025] According to one possible embodiment, the drive system can be assigned to multiple operating devices. Each operating device is assigned a power unit. The power units are communicatively connected to the control unit. The first switching devices of the multiple operating devices are combined into a first switching device group. The at least one second switching device of the multiple operating devices is combined into at least one second switching device group. Each motor can be assigned a power unit. However, one power unit can also drive all motors.

[0026] According to one possible embodiment of the invention, the at least one second switching means can consist of a second switching means and a third switching means. In this case, the second switching means are combined to form a second switching means group, and the third switching means are combined to form a third switching means group.

[0027] According to a possible further embodiment of the invention, the operating means can comprise the first switching means and a plurality of second switching means. Each of the further second switching means is connected to the second motor via the drive shaft. The second switching means are combined to form a second switching means group.

[0028] The control unit and / or the power unit can each be equipped with a memory. Specific switching positions or positions of the switching elements can be stored in the memory, which are assigned, for example, to a value for the position of the drive shaft.

[0029] A possible embodiment of the drive system of the present invention can comprise a first motor, a second motor, and a third motor. The motors are driven, for example, via a gearbox and a drive shaft. The control device of the drive system comprises a power section, which, for example, comprises a converter for the controlled or regulated power supply to the motors. The control unit serves to control the power section. The control unit is connected to the power section, for example, via a bus. The drive system has several feedback systems that are functionally assigned to the drive shaft or the respective motors. Each of the feedback systems can be a sensor system. Likewise, the sensor system can be part of the feedback systems. The feedback systems or the sensor systems are connected to the power section.

[0030] According to one possible embodiment, the equipment can be a distribution transformer, a transmission transformer, or a distribution transformer. The switching devices can be diverter switches, selectors, preselectors, reversing switches, or double reversing switches. Parameters for a locking condition can be the positions, position, or movement state of the diverter switch, selector, preselector, reversing switch, or double reversing switch. A parameter can be configured as a value or a range of values. A parameter can be queried by a control unit or transmitted to it. Multiple parameters can be combined into one parameter.

[0031] The first switching device can be designed as a single-phase or multi-phase load transfer switch. The second switching device can be designed as a selector, pre-selector, reversing switch, or double reversing switch, in particular single-phase or multi-phase.

[0032] The invention and its advantages will now be explained in more detail by means of exemplary embodiments with reference to the accompanying drawings, without thereby limiting the invention to the exemplary embodiment shown. The proportions in the figures do not always correspond to the actual proportions, as some shapes are simplified and others are shown enlarged relative to other elements for better illustration.

[0033] It shows Figure 1 shows a possible embodiment of the drive system for at least one switching means in an operating device; Figure 2 shows a further embodiment of the drive system for at least one switching means in an operating device; Figure 3 shows a further embodiment of the drive system according to the invention for at least one switching means in an operating device, wherein a plurality of operating devices are provided; Figure 4 shows a further possible embodiment of the drive system according to the invention for at least one switching means in an operating device; and Figure 5 shows a method sequence for carrying out a switching of a switching means in an operating device by means of the drive system according to the invention.

[0034] Identical reference numerals are used for identical or equivalently functioning elements of the invention. Furthermore, for the sake of clarity, only those reference numerals are shown in the individual figures that are necessary for the description of the respective figure.

[0035] Figure 1 shows an energy transmission device 20, which is in particular a transformer. The device 20 comprises a first switching device 17 and a second switching device 18. A first motor 12 is connected to the first switching device 17 via a drive shaft 16. A second motor 13 is connected to the second switching device 18 via a drive shaft 16. Although the following description is limited to transformers as the device 20 and to load transfer switches or selectors as the switching devices 17 or 18, this should not be construed as a limitation of the invention.

[0036] At the Figure 1In the described embodiment, the first switching means 17 is designed as a load transfer switch. The second switching means 18 is designed as a selector. The load transfer switch (first switching means 17) is actuated by means of the first motor 12. The motor 12 has a drive shaft 16 connected to the load transfer switch. Furthermore, the motor 12 has a first feedback system 6 with which the position of the first switching means 17 (load transfer switch) can be determined. The selector (second switching means 18) is actuated by a second motor 13. This second motor 13 is also connected to the selector via a drive shaft 16. A second, separate feedback system 7 of the second motor 13 makes it possible to determine the position or step position of the selector.

[0037] A control device 2 according to the invention comprises a control unit 10, which is connected to the first motor 12 and the second motor 13, and thus also to the first feedback system 6 and the second feedback system 7 of the first and second switching means 17 and 18, via a power section 11. The control unit 10 receives the signals for actuating the first and second switching means 17 and 18, i.e., the load transfer switch and the selector. Furthermore, different values ​​of the respective feedback systems 6 and 7 are evaluated and combined in the control unit 10. The control unit 10, the first motor 12 and the second motor 13, the feedback systems 6 and 7, and the power section 11 form a drive system 3 for the first switching means 16 and the second switching means 17, respectively, of the operating means 20.

[0038] The control device 2 receives switching signals during operation. If, for example, the voltage in the power grid drops, it must be adjusted, for example by operating the diverter switch or the diverter switch and the selector. By using a selector with appropriate wiring of the transformer windings, the control range of a transformer is extended. After receiving the signal that the voltage needs to be changed, it is first determined whether only the diverter switch or the diverter switch and the selector need to be operated one after the other. After it has been determined that only the diverter switch needs to be operated, the interlocking condition(s) defined between the selector and the diverter switch are checked / queried. For example, a diverter switch must not be operated if the selector is currently being operated.The check is carried out in such a way that the second feedback system 7 of the second motor 13 of the second switching means 18 (selector) reports the current status or transmits parameters to the control unit 10. The position or setting of the second switching means 18 (selector) is determined and transmitted via the second feedback system 7. The second feedback system 7 also reports whether the second switching means 18 (selector) is currently being actuated. If the determined parameters fulfill the locking conditions, the load diverter switch is actuated. If the locking conditions have not been met, the load diverter switch is not actuated. Alternatively, the switching or actuation of the load diverter switch can be delayed until the locking conditions are met, i.e., the selector is in a certain position or has stopped moving. Furthermore, the actuation can be aborted and / or an error signal can be generated.

[0039] The control device 2 comprises a control unit 10 with a memory 5 and at least one power section 11 with a memory 5. For example, an assignment of switching positions of the first switching means 17 (load transfer switch) and the second switching means 18 (selector) can be stored in the memory 5. Likewise, the values ​​for the positions of the individual drive shafts 16 can be stored in the memory 5.

[0040] Figure 2shows a further embodiment of the described drive system 3 for at least three switching means 17, 18, and 19 of an operating means 20. In this embodiment, three switching means 17, 18, and 19 are provided. The first switching means 17 is a load transfer switch. The second switching means 18 is a selector. The third switching means 19 is a preselector. Each of the three switching means 17, 18, and 19 is actuated by its own motor 12, 13, and 14. Each of the three switching means 17, 18, and 19 is assigned a feedback system 6, 7, and 8. Here, too, different locking conditions can be checked in the control unit 10. For this purpose, the parameters of the feedback systems 6, 7, and 8 are queried. For example, in the embodiment described here, actuation of the pre-selector (third switching means 19) is only possible if the selector (second switching means 18) and the load changeover switch (first switching means 17) are in a certain position and are not actuated.The preselector (third switching means 19), for example, should only be operated when the on-load tap changer (first switching means 17) and the selector (second switching means 18) are essentially only connected to the main winding of the transformer (not shown) and the winding (coarse stage or regulating winding) which is to be reversed by the preselector (third switching means 19) is not connected.

[0041] Figure 3 shows a further possible embodiment of the drive system 3 according to the invention, as in Figure 3 described, with three operating devices 20. Three operating devices 20 can in particular be three transformers, whose taps (not shown) are connected in a coordinated manner to the three switching devices 17, 18 and 19 by means of the common control unit 10. The three switching devices 17, 18 and 19 assigned to each of the transformers (operating devices 20) correspond in their function to the three in Figure 2described switching devices 17, 18 and 19. After receiving a switching signal, a check is first made to determine which of the switching devices 17, 18 or 19 needs to be actuated. For this purpose, three switching device groups 30, 40 and 50 can be formed. The first switching device group 30 consists of the first switching devices 17, namely the load transfer switches, in the respective transformers (equipment 20). A second switching device group 40 represents the second switching devices 18, namely the selectors. A third switching device group 50 represents the third switching devices 19, namely the preselectors 50. Before an actuation, a check is made to determine whether the specific switching device group 30, 40 or 50 fulfills the locking conditions. Here, for example, a check is carried out to determine the position of each of the selectors (second switching device 18) of the three equipment 20 and whether any of them are moving.The locking conditions are checked based on the parameters of the respective feedback systems 6, 7, and 8, which are assigned to the respective switching devices 17, 18, and 19 in each of the operating devices 20. The power unit 11, which is assigned to each drive system 3 of each operating device 20, is connected to a central and single control unit 10 via a bus 21. The actuation of the respective switching devices 17, 18, and 19 for each of the three operating devices 20 is coordinated and controlled by the central control unit 10. As shown in . Figure 2 As already described, the power unit 11 accesses the motors 12, 13 or 14 assigned to the respective switching means 17, 18 and 19.

[0042] Figure 4shows a further possible embodiment of the described drive system 3. In this case, the first switching means 17 is a load transfer switch, and the other three second switching means 18 are three single-phase selectors. The first switching means 17 is actuated by the first motor 12 assigned to it. The first feedback system 6 is assigned to the first switching means 17. The three second switching means 18 are each actuated by their own second motor 13 and each have a second feedback system 7. Alternatively, all three selectors can be actuated by a common second motor 7. Here, too, different locking conditions can be checked in the control unit 10 by querying the parameters of the first and second feedback systems 6 and 7. The load transfer switch (first switching means 12) is designed as a three-phase switch here. The selectors (second switching means 18) can be combined to form a switching means group 40.

[0043] Figure 5 shows a method sequence according to the invention. Here, the control device 2 receives a switching signal for the actuation of an on-load tap changer, which preferably has a first switching means 17 and a second switching means 18, i.e., a load diverter switch and a selector. This switching signal can be generated, for example, by manual input during maintenance work. Alternatively, the switching signal can be issued by a voltage regulation device, for example, when the voltage at the operating device 20, i.e., the transformer, drops or rises. After receiving the switching signal, it is first determined which of the switching means 17 or 18, or both switching means 17 and / or 18, must be actuated. After selecting the switching means 17 and 18 to be actuated, the control unit 10 queries at least one parameter. In the example from Figure 1For example, the queried parameter is the position of the selector, i.e., the second switching device 18, which is determined by the associated second feedback system 7 of the second motor 13. At least one locking condition is stored in the memory 5 of the control unit 10, which can be fulfilled or not fulfilled by the at least one parameter. If the locking condition is fulfilled during the check, the first switching device 17 is switched over, i.e., the load diverter switch is actuated. If the locking condition is not fulfilled during the check, the first switching device 17 is not actuated, and therefore no switching takes place. The control unit 10 can then wait until the parameter fulfills the locking condition and then performs the switching. Alternatively, the switching can be aborted before it begins. The triggering of an error signal is also possible. Based on the example in Figure 1Before operating a load diverter switch (first switching device 17), the position of the selector (second switching device 18) would first be checked and / or whether it is currently being moved, i.e., whether it is currently being operated. Due to the locking conditions in this example, the load diverter switch (first switching device 17) may not be operated if the selector (second switching device 17) is currently being operated or, for example, is in an unsuitable / prohibited position. The parameters required to check the locking conditions are output by the second feedback system 7 of the second motor 13 of the selector (second switching device 18). The second feedback system 7 is designed, for example, as a multi-turn encoder that is directly or indirectly connected to the drive shaft 16, which is arranged between the second motor 13 and the selector (second switching device 18).The multi-turn encoder then determines the parameters, such as the position of the selector (second switching means 18) based on the position of the drive shaft 16.

[0044] Depending on the design of the drive system 3, different parameters can be combined with different locking conditions. For example, as in the embodiment in Figure 2 As shown, before operating the diverter switch (first switching device 17), the position (positions) of the selector and the pre-selector (second and third switching devices 18 and 19) are checked. Alternatively, before operating the selector (second switching device 18), the locking condition, i.e., the parameters of the diverter switch (first switching device 17) and the pre-selector (third switching device 19), are checked. Here, too, the parameters are queried via the respective feedback systems 6 and 8, which are designed as multi-turn encoders.

[0045] The parameters to be queried can be determined arbitrarily and can be of any type. The parameters can originate from feedback systems 6, 7, and 8 on the respective motors 12, 13, and 14 of the respective switching devices 17, 18, and 19, from simple safety switches of device 20, or even from customer-specific release buttons.

[0046] The locking conditions define which conditions must be met for a switchover to not be "locked," i.e., blocked. These conditions are linked to parameters that are formed or defined by the positions of switching devices 17, 18, and 19, the current states, and the movement states.

[0047] The locking conditions can use one or more parameters from one or any number of feedback systems 6, 7 and 8.

[0048] The parameters can be, for example, the movement states of switching devices, position or setting of switching devices, position range or setting range of switching devices, temperatures of operating devices, customer-specific switching signals, safety devices and the like.

[0049] The switching devices can be load transfer switches, selectors, reversing switches, and double reversing switches. These can be single-phase or multi-phase. Reference symbol

[0050] 2Control device 3Drive system 5Memory 6First feedback system 7Second feedback system 8Third feedback system 10Control unit 11Power unit 12First motor 13Second motor 14Third motor 16Drive shaft 17First switching device 18Second switching device 19Third switching device 20Operating device 21Bus 30First switching device group 40Second switching device group 50Third switching device group

Claims

1. Method for bushing an advanced retard switch operation of a first switching means (17), which is a single-phase or polyphase diverter switch, or at least one second switching means (18, 19), which is single-phase or polyphase and is in each case a selector, change-over selector, reversing change-over selector or double reversing change-over selector, of an equipment (20), which is a transformer, comprising the following steps: - a control unit (10) receives a switching signal; - the first switching means (17) or the at least one second switching means (18, 19) is selected for advanced retard switching by means of the control unit (10) on the basis of the switching signal; - at least one parameter of the first switching means (17) or of the at least one second switching means (18, 19) is interrogated by the control unit (10); characterized by the following steps - in that an interlocking condition for the first switching means (17) or an interlocking condition for the at least one second switching means (18, 19) is checked on the basis of the at least one queried parameter; and - in that the advanced retard switch is bushed by means of the selected first switching means (17) or the at least one second switching means (18, 19) if the corresponding interlocking condition is fulfilled; wherein the at least one parameter indicates a position and / or a movement state of the first switching means or of the at least one second switching means; and wherein a respective interlocking condition based on the at least one parameter defines whether a respective advanced retard switch is inhibited, such that the advanced retard switch can take place when the interlocking condition is fulfilled.

2. The method according to claim 1, wherein the at least one parameter of the first switching means (17) is determined by means of a first feedback system (6) and the at least one parameter of the at least one second switching means (18, 19) is determined by means of a second feedback system (7, 8) associated with the at least one second switching means (18, 19).

3. Method according to claim 2, wherein in the control unit (10) the queried parameters of the first switching means (17) and / or of the at least one second switching means (18, 19) are evaluated and combined, and wherein these parameters further comprise: one or more temperatures, customer-specific switching signals, a status of a circuit breaker or of a safety device.

4. The method according to any one of claims 2 - 3, wherein, for bushing the advanced retard switch, a power section (11) associated with the equipment (20) is controlled by the control unit (10) to actuate the selected first switching means (17) or the selected at least one second switching means (18, 19), and the power unit (11), depending on the bushing of the advanced retard switch, actuates a first motor (12) connected to the first switching means (17) via a drive shaft (16) and a second motor (13) connected to the at least one second switching means (18, 19) via a drive shaft (16) in each case.

5. Method according to claim 4, wherein each feedback system (7, 8, 9) is assigned directly or indirectly to the respective drive shaft (16) of the switching means (17, 18, 19).

6. Method according to one of claims 1 to 5, wherein the method is bushed for first switching means (17) and second switching means (18, 19) of a plurality of pieces of equipment (20), wherein each of the plurality of pieces of equipment (20) is assigned a power section (11) and the power sections (11) are controlled by the control unit (10), wherein the respective first switching means (17) of the plurality of pieces of equipment (20) are combined to form a first switching means group (30) and the respective at least one second switching means (18, 19) are combined to form at least one second switching means group (40, 50).

7. Drive system (3) for at least two switching means (17, 18, 19) of a piece of equipment (20), wherein: - a first switching means (17) is connected to a first motor (12) via a drive shaft (16); - at least one second switching means (18, 19) is connected via a respective drive shaft (16) to a respective second motor (13, 14) - a feedback system (6, 7, 8) is assigned to the first motor (12) and to each second motor (13, 14) in order to determine at least one parameter of the switching means (17, 18, 19); characterized by - a control unit (10) communicatively connected to a power section (11) for actuating the first switching means (17) with the first motor (12) or the corresponding respective second switching means (18, 19) with the respective second motor (18, 19), provided that interlocking conditions based on at least one determined parameter and checked by the control unit (10) are fulfilled; wherein the at least one parameter indicates a position and / or a movement state of the first switching means or of the at least one second switching means; and wherein a respective interlocking condition based on the at least one parameter defines whether a respective advanced retard switch is blocked, such that the advanced retard switch can take place if the interlocking condition is fulfilled.

8. The drive system (3) according to claim 7, wherein the at least one second switching means (18, 19) comprises a second switching means (18) connected to a second motor (13) and a third switching means (19) connected to a third motor (13).

9. Drive system (3) according to one of claims 7 to 8, wherein the drive system (3) is assigned to a plurality of pieces of equipment (20), a power section (11) is assigned to each piece of equipment (20) and the power sections (11) are communicatively connected to the control unit (10), wherein the first switching means (17) of the plurality of pieces of equipment (20) are combined to form a first switching means group (30) and the at least one second switching means (18, 19) of the plurality of pieces of equipment (20) are combined to form at least one second switching means group (40, 50).

10. Drive system (3) according to claim 9, wherein the at least one second switching means (18, 19) of each piece of equipment (20) comprises a second switching means (18) and a third switching means (19), wherein the second switching means (18) are combined to form a second switching means group (40) and the third switching means (19) are combined to form a third switching means group (50).

11. Drive system (3) according to claim 7, wherein each of the second switching means (18) is connected to the respective second motor (13) via the respective drive shaft (16) and the second switching means (18) are combined to form a second switching means group (40).

12. Drive system (3) according to any one of claims 7 to 11, wherein the control unit (10) and the power unit (11) each comprise a memory (5).