SWITCH ARRANGEMENT AND PROCEDURES FOR THE SAFE OPERATION OF A SWITCH ARRANGEMENT

Abstract

Switch arrangement comprising a switch (17) and a drive system for the switch (17), the drive system (2) - a motor (12) to drive the switch (17); - a control device (1) with a power section (11) for supplying energy to the motor (12) and a control unit (10) for initiating a switching operation of the switch (17) by controlling the power section (11); and - a protective circuit (14) set up for this purpose - in the event of a malfunction of the control unit (10), to detect an initial fault signal via a status contact of the control unit (10); and - in the event of a malfunction of the power section (11), to detect a second fault signal via a status contact of the power section (11); - to initiate a safety measure depending on the first and second error signals; - wherein the control device (1) is configured to activate the protective circuit (14) before the initiation of the switching operation and to deactivate it after successful completion of the switching operation.

Description

[0001] The invention relates to a switch arrangement comprising a switch and a drive system for the switch, an electrical operating means comprising a switch arrangement and a method for the safe operation of a switch arrangement.

[0002] Substations contain a variety of switches for different tasks and with different requirements. To operate the respective switches, they must be driven by a drive system. These switches include on-load tap-changers, diverter switches, selectors, double reversing switches, reversing switches, pre-selectors, circuit breakers, load switches, or disconnectors.

[0003] For example, on-load tap-changers are used for uninterrupted switching between different winding taps of an electrical device, such as a power transformer or a variable-speed reactor. This allows, for example, the transformer's transformation ratio or the reactor's inductance to be changed. Double reversing tap-changers are used to reverse the polarity of windings during power transformer operation.

[0004] US 2015 / 0 0 61 806 A1 discloses an on-load tap-changer based on the reactor switching principle. This has a drive system which includes a feedback device, a detector, a monitoring system and a servo drive. The servo motor itself is controlled by means of the servo drive. Here, a controller operates in the low voltage section using, among other things, PI or PID algorithms. The controller signals are transmitted to the high voltage section. The disclosed servo drive is a combination of a low voltage section and a high voltage section. The low voltage section has a controller and registers. The drive system also has an HMI, a so-called "human machine interface", which is part of a monitoring system.

[0005] DE 1 239 012 A discloses a protective device for tap selectors. A first part of the protective device comprises current transformers arranged in the selector lines. An auxiliary relay is located in the secondary circuit of each of these two transformers. The secondary circuit monitors the current in the selector arms. During a switchover, the selector arm that moves to the new winding tap must not be energized. This is monitored by the current transformers. Should a current nevertheless flow during the switchover of the selector arm to be actuated, the auxiliary relay in the secondary circuit disconnects the transformer from the mains or switches off the motor drive. Furthermore, a short-circuit relay (second protective device) is provided, which switches off the motor drive if a tap short circuit flows through one or both selector lines.

[0006] DE 40 09 038 A1 discloses a method and an arrangement for a monitoring system for tap changers for tapped transformers that use vacuum switchgear as load transfer switches. Current transformers are provided in the power supply lines of the vacuum switchgear, each of which acts on a fiber optic cable through which the respective electrical status in the phases is transmitted and compared in a detection logic at two specified synchronous times, and, if necessary, an error signal is generated from this.

[0007] US 2007 / 0 057 652 A1 discloses a tap-change transformer with a tap changer. The tap changer has means for controlling a motor that actuates the tap changer.

[0008] All of these switches represent a highly safety-relevant component of electrical equipment because the switching occurs while the equipment is in operation and is therefore connected to a power grid, for example. In extreme cases, malfunctions during operation can have serious technical and economic consequences.

[0009] It is therefore an object of the present invention to provide an improved concept for driving a switch, in particular an on-load tap changer, load diverter switch, selector, double reversing switch, reversing switch, pre-selector, by means of which the safety of operation is increased.

[0010] This object is achieved by the respective subject matter of the independent claims. Further embodiments are the subject matter of the dependent claims.

[0011] The improved concept is based on the idea of ​​detecting faults in a control unit, a motor, and a power unit driving a switch with a protective circuit and initiating a safety measure if necessary. Motor faults are detected indirectly via the power unit. The protective circuit is activated before the switch initiates a switching operation and deactivated after the switching operation has been successfully completed.

[0012] According to the improved concept, a switch arrangement comprising a switch and a drive system for the switch is specified. The drive system comprises a motor for driving the switch, a protective circuit, and a control device with a power unit for supplying energy to the motor. The control device further comprises a control unit for initiating a switching operation of the switch by controlling the power unit. The protective circuit is configured to detect a first error signal via a status contact in the event of a fault in the control unit and to detect a second error signal via a status contact of the power unit in the event of a fault in the power unit or the motor. Furthermore, the protective circuit is configured to initiate a safety measure depending on the first and second error signals.The control device, in particular the control unit and / or the power unit, is designed to activate the protective circuit before initiating the switching operation of the switch and to deactivate it after the switching operation has been successfully carried out.

[0013] According to at least one embodiment of the switch arrangements, the switching operation comprises a complete switching of the switch, in the case of an on-load tap-changer, therefore a complete switching between two winding taps of an electrical operating means associated with the switch arrangement, such as a power transformer or a choke.

[0014] According to at least one embodiment, the switch of the switch arrangement is an on-load tap changer or a selector or a pre-selector or a load diverter switch or a reversing switch or a double reversing switch.

[0015] According to at least one embodiment, the switching operation comprises part of the switching of the switch.

[0016] According to at least one embodiment of the switch arrangements, the switching operation comprises a complete switching of an on-load tap-changer, i.e. a complete switching between two winding taps of an electrical equipment associated with the on-load tap-changer, such as a power transformer or a choke.

[0017] According to at least one embodiment, the switching operation comprises a part of the switching of the on-load tap-changer, for example a pre-selector circuit, a selector circuit or a load transfer circuit or a respective part thereof.

[0018] In general, the switching process can correspond to a critical part of the switching process, during which a fault in the motor or the power unit can have serious consequences, for example a stage short circuit.

[0019] According to at least one embodiment, the protection circuit detects the error signals only in the activated state and / or initiates the safety measure only in the activated state.

[0020] According to at least one embodiment, the protection circuit is formed separately from the power unit, the control unit and the motor.

[0021] According to at least one embodiment, parts of the protection circuit are comprised by the power unit, the control unit and / or the motor.

[0022] According to at least one embodiment, initiating the safety measure comprises outputting a signal at an output of the protective circuit, for example short-circuiting two output contacts.

[0023] According to at least one embodiment, the switch can be assigned to an electrical device or installed on or in the electrical device. The safety measure comprises isolating the device from a power grid, for example, by operating a circuit breaker. When the circuit breaker is not operated, it connects the device to the power grid.

[0024] By monitoring the status contacts of both the control unit and the power section (as well as the motor connected to the power section), and initiating the appropriate safety measure through the activated protective circuit, the operational reliability of the switch assembly or equipment can be increased. Safety risks caused by faults in movement-relevant components such as the motor and power section during critical switching operations are reduced. This is particularly advantageous for critical switching operations that can no longer be stopped or can no longer be safely stopped once they have been initiated, or for critical switching operations that cannot be stopped because this would result in an impermissible state of the switch.

[0025] If the protective circuit is not activated, for example, if the switch is in a safe or non-critical position or state, the safety measure is not initiated, and in particular, the equipment is not disconnected from the power grid. Therefore, the availability of the equipment remains guaranteed despite increased safety.

[0026] According to at least one embodiment, the protective circuit is configured to initiate the safety measure only if the first error signal indicates a fault in the power unit (or the motor) and the second error signal indicates a fault in the control unit. It is possible that further conditions must be met for the safety measure to be initiated.

[0027] In such embodiments, the safety measure is only initiated when several, for example all, components of the switch arrangement fail or malfunction.

[0028] According to at least one embodiment, the switch arrangement is configured to react to a malfunction or failure of a movement-relevant component by initiating a further safety measure.

[0029] In such embodiments, for example, the initiation of further safety measures can depend on specific conditions, such as the position of the switch. The protective circuit is not necessarily relevant here. Only when several, in particular all, components indicate faults does the protective circuit, if activated, initiate the safety measure.

[0030] According to at least one embodiment, the switch, in particular an on-load tap-changer, comprises a storage device for storing mechanical energy, for example, a spring energy store. The storage device can be charged by the drive system via a drive shaft and, upon reaching a specific position of the drive shaft, can release the stored energy abruptly, so that the load transfer can take place within a very short time. This ensures that an initiated load transfer is always completed. In such embodiments, the drive system can be designed as a servo drive system, but this is not mandatory. In such embodiments, the switching process can, for example, include a preselector circuit.

[0031] According to at least one embodiment, the switch is designed as a directly driven on-load tap-changer. This means that it does not have a storage device for storing mechanical energy, and the drive system is designed as a servo drive system. In such embodiments, other suitable means, such as the drive system, must ensure that, for example, the load transfer is completed once initiated. In such embodiments, it is particularly advantageous if the switching process includes the load transfer.

[0032] According to at least one embodiment, the control unit is configured to activate the protective circuit before initiating the switching process and / or to deactivate it after the switching process has been successfully carried out.

[0033] According to at least one embodiment, the power unit is configured to activate the protective circuit before initiating the switching operation and / or to deactivate it after the switching operation has been successfully carried out.

[0034] According to at least one embodiment, the control unit is configured to activate the protective circuit before initiating the switching operation and to deactivate the power unit after the switching operation has been successfully carried out.

[0035] According to at least one embodiment, the power unit is configured to activate the protective circuit before initiating the switching operation and to deactivate the control unit after the switching operation has been successfully carried out.

[0036] According to at least one embodiment, the protective circuit comprises a bistable switching element, in particular a bistable relay. The control device, in particular the control unit, is configured to actuate the bistable switching element to activate and / or deactivate the protective circuit. The control device, in particular the power unit, is configured to actuate the bistable switching element to activate and / or deactivate the protective circuit.

[0037] According to at least one embodiment, the protective circuit comprises a series circuit connected to a first switch unit, a second switch unit, and the bistable switching element. The first switch unit is coupled to the status contact of the power unit, and the second switch unit is coupled to the status contact of the control unit.

[0038] According to at least one embodiment, the first switch unit comprises one or more switches connected in parallel, at least one of which must be closed in order for the protective circuit to initiate the safety measure.

[0039] According to at least one embodiment, the second switch unit comprises one or more switches connected in parallel, at least one of which must be closed so that the protective circuit can initiate the safety measure.

[0040] According to at least one embodiment, the first switch unit has one or more switches connected in parallel, each of which can be closed by an individual power unit. According to at least one embodiment, the drive system is designed as a servo drive system. The power unit comprises one or more converters, in particular servo converters, or equivalent electronic, in particular fully electronic, units for drive motors. In particular, the power unit comprises one converter per driven axle.

[0041] According to at least one embodiment, the on-load tap-changer is designed to be multiphase, in particular for a multiphase operating device. The power section has one converter per phase.

[0042] According to at least one embodiment, the power unit is designed as an electromechanical unit for drive machines.

[0043] According to at least one embodiment, the switch arrangement comprises a further movement-relevant component, in particular a further motor or a further power unit. The protective circuit comprises a further switch unit connected in series with the first and second switch units and coupled to a status contact of the further movement-relevant component. The further switch unit comprises one or more switches connected in parallel, at least one of which must be closed for the protective circuit to initiate the safety measure.

[0044] According to the improved concept, an electrical device is also specified that includes a switch arrangement according to the improved concept, for example, a tap-changer arrangement. The on-load tap-changer of the tap-changer arrangement is assigned to the electrical device or installed on or in the electrical device. The safety measure comprises disconnecting the device from a power grid.

[0045] According to the improved concept, an equipment arrangement is also specified. The equipment arrangement comprises an electrical equipment according to the improved concept and a circuit breaker for isolating the equipment from the power grid, wherein the safety measure involves actuating the circuit breaker.

[0046] According to the improved concept, a method for the safe operation of a switch arrangement is also specified. The method comprises activating a protective circuit, initiating a switching operation of the switch by controlling the power section after the protective circuit has been activated, detecting a first error signal via a status contact of a motor of the drive system, detecting a second error signal via a status contact of a power section of the drive system, initiating a safety measure depending on the first and second error signals, and deactivating the protective circuit after the switching operation has been successfully completed.

[0047] According to the improved concept, a method for the safe operation of a tap-changer arrangement is also specified. The method comprises activating a protective circuit, initiating a switching operation of the on-load tap-changer by controlling the power section after the protective circuit has been activated, detecting a first error signal via a status contact of a motor of the drive system, detecting a second error signal via a status contact of a power section of the drive system, initiating a safety measure depending on the first and second error signals, and deactivating the protective circuit after the switching operation has been successfully completed.

[0048] Further embodiments and implementations of the method, the equipment and the equipment arrangement result directly from the various embodiments of the switch arrangement and vice versa.

[0049] 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.

[0050] It shows Fig. 1 is a schematic representation of an exemplary embodiment of a switch assembly according to the improved concept; Fig. 2 is a schematic representation of a protection circuit of an exemplary embodiment of a switch arrangement according to the improved concept; and Fig. 3 is a schematic diagram of a protection circuit of another exemplary embodiment of a switch assembly according to the improved concept.

[0051] Fig. 1 shows a schematic representation of an exemplary embodiment of a switch arrangement 2 according to the improved concept with a switch 17 and a drive system connected to the switch 17 via a drive shaft 16. The drive system includes a motor 12, which can drive the drive shaft 16 via a motor shaft 13 and optionally via a gear 15. A control device 1 of the servo drive system comprises a power section 11, which contains, for example, one or more converters, for the controlled or regulated power supply of the motor 12, as well as a control unit 10 for controlling the power section 11, for example via a bus 18. The switch arrangement 2 can be assigned to an electrical device 19, such as a power transformer, or can be installed in or on the device 19.

[0052] In particular, the switch arrangement can be single-phase or multi-phase. The power section 11 can contain a respective converter for each phase.

[0053] The switch arrangement also has a protection circuit 14 which is coupled to a status contact of the motor 12, to one or more status contacts of the power section 11, in particular the converter of the power section 11, and to the control unit 10.

[0054] The switch arrangement 2, in particular the protective circuit 14, can be connected, for example, to a disconnecting device 20, in particular a circuit breaker, which can disconnect the operating device 19 from a power network 21.

[0055] During operation of the switch assembly 2, the control unit 10 initiates a switching operation of the switch 17, for example, a switching operation between two winding taps of the operating device 19 or a part of the switching operation. The control unit 10 can activate the protective circuit 14 before initiating the switching operation, particularly if the switching operation represents a critical operation, such as a load transfer or a preselector actuation of the switch 17.

[0056] If the switching process has been carried out successfully, i.e. without errors or malfunctions, the control device, for example the power unit 11, can deactivate the protective circuit 14.

[0057] If a malfunction or error occurs during the switching process such that both the controller 10 and the motor 12 and / or the power section 11, in particular at least one converter of the power section 11, fail, the protective circuit 14 detects this via respective error signals at the status contacts, or the respective error signals trigger the status contacts of the protective circuit and initiate a safety measure. For this purpose, the protective circuit 14 can, for example, output an output signal, which can lead to the actuation of the disconnecting device 20, for example, by short-circuiting two output contacts of the protective circuit 14. The safety measure is initiated without any further check of the status or position of the switch 17.

[0058] If a fault occurs in the motor 12 or the power section 11 during the switching process, but not in the motor 12 and the power section 11, the protective circuit 14 does not initiate the safety measure. In such a case, the control unit 10 can, for example, initiate a safety measure depending on a state or position of the switch 17, for example, by actively triggering the disconnecting device 20. Furthermore, the deactivation of the protective circuit 14 can then be omitted, for example.

[0059] Fig. Figure 2 shows a schematic representation of a protection circuit 14 of an exemplary embodiment of a switch arrangement according to the improved concept, in particular as with respect to Fig. 1 described.

[0060] The protection circuit 14 includes a series circuit consisting of a bistable switching element 22, for example, a bistable relay, a first switch unit 23, a second switch unit 24, and an output element 28, which can be implemented, for example, as a switch or relay. The series circuit is arranged between a supply voltage 29 and a reference voltage.

[0061] The bistable switching element 22 can be actuated by the control device 1. Before initiating the switching operation, the control unit 10 can actuate the bistable switching element 22 to connect the series circuit to the supply voltage 29 and thus activate the protection circuit 14. Before the switching operation begins, both the first switch unit 23 and the second switch unit 24 are open.

[0062] If a fault occurs in the control unit 10 while the protective circuit 14 is activated, the first switch unit 23 is closed. If a fault occurs in the power section 11, in particular all converters of the power section 11, or in the motor 12 while the protective circuit 14 is activated, the second switch unit 24 is closed. If both switch units 23, 24 are closed, the output element 28 is connected to the supply voltage 29 and outputs an output signal to initiate the safety measure, for example, to the isolating device 20 to actuate it.

[0063] If, however, the switching process is successfully completed, in particular without any malfunctions or errors of the motor 12 or the power unit 11, the power unit 11 can actuate the bistable switching element 22 in order to disconnect the series circuit from the supply voltage 29 and thus deactivate the protective circuit 14.

[0064] Fig. Figure 3 shows a schematic representation of a protection circuit 14 of a further exemplary embodiment of a switch arrangement according to the improved concept, in particular as with respect to Fig. 1 described.

[0065] The second switch unit 24 here has several switches 25, 26, 27 connected in parallel, each of which is assigned to a respective converter of the power section 11. By way of example and without limitation of generality, Fig. 3 parallel switches 25, 26, 27 are shown, each of which is assigned to one of three converters of the power section 11.

[0066] Each of the switches 25, 26, 27 is closed by the power unit 11 or the associated converter or motor if a fault or error occurs in the corresponding converter during the switching process. Due to the parallel connection, closing one of the switches 25, 26, 27 corresponds to closing the first switch unit 24.

[0067] In addition, the protection circuit 14 is constructed like the one with respect to Fig. 2. Reference is therefore made to the relevant explanations.

[0068] The improved design increases the operational reliability of the tap-changer arrangement and the equipment. The functionality of the protective circuit ensures consistently defined, safe operation of the system, even if all components fail during a switching operation. This safety circuit is also characterized by the fact that it can be tested cyclically without tripping a circuit breaker. In a safe position, i.e., with the protective circuit deactivated, a failure of all components has no effect on the circuit breaker tripping, thus ensuring availability. Reference symbol 1 control device 2 Switch arrangement 10 Control unit 11 Power section 12 Engine 13 Motor shaft 14 protective circle 15 gearboxes 16 Drive shaft 17 switches 18 buses 19 Operating resources 20 Separator 21 Energy network 22 bistable switching element 23 switch units 24 switching unit 25, 26, 27 switches 28 Output element 29 Supply voltage

Claims

[1] Switch arrangement comprising a switch (17) and a drive system for the switch (17), the drive system (2) including - a motor (12) for driving the switch (17); - a control device (1) with a power unit (11) for supplying energy to the motor (12) and a control unit (10) for initiating a switching operation of the switch (17) by controlling the power unit (11); and - a protective circuit (14) arranged to - in the event of a fault in the control unit (10), to detect a first error signal via a status contact of the control unit (10); and - in the event of a fault in the power section (11), to detect a second error signal via a status contact of the power section (11); - to initiate a safety measure depending on the first and second error signal; - wherein the control device (1) is configured to activate the protective circuit (14) before initiating the switching operation and to deactivate it after the switching operation has been successfully carried out. [2] Switch arrangement according to claim 1, wherein the protective circuit (14) is arranged to initiate the safety measure only when the first and the second error signal indicate faults in the controller (10) and the power section (11). [3] Switch arrangement according to one of claims 1 or 2, wherein - the protective circuit (14) comprises a bistable switching element (22); and - the control device is designed to actuate the bistable switching element (22) in order to activate or deactivate the protective circuit (14). [4] Switch arrangement according to claim 3, wherein the bistable switching element (22) comprises a bistable relay. [5] Switch arrangement according to one of claims 3 or 4, wherein the protective circuit (14) - a first switch unit (23) and a second switch unit (24) connected in series to each other and to the bistable switching element (22); - wherein the first switch unit (23) is coupled to the status contact of the motor (12) and the second switch unit (24) is coupled to the status contact of the power unit (11). [6] Switch arrangement according to claim 5, wherein the first switch unit (23) comprises one or more switches connected in parallel, at least one of which must be closed so that the protective circuit (14) can initiate the safety measure. [7] Switch arrangement according to one of claims 5 or 6, wherein the second switch unit (24) has one or more switches (25, 26, 27) connected in parallel, at least one of which must be closed so that the protective circuit (14) can initiate the safety measure. [8] Switch arrangement according to one of claims 5 to 7, wherein - the switch arrangement has another movement-relevant component; - the protective circuit (14) has a further switch unit which is connected in series with the first and second switch units (23, 24) and is coupled to a status contact of the further movement-relevant component; and - the further switch unit has one or more switches connected in parallel, at least one of which must be closed so that the protective circuit (14) can initiate the safety measure. [9] Switch arrangement according to one of claims 1 to 8, wherein - the switch (17) can be assigned to an electrical device (19) or can be installed on or in the electrical device (19); and - the safety measure includes or can trigger a separation of the equipment (19) from a power grid (21). [10] Switch arrangement according to one of claims 1-9, wherein - the switch (17) is an on-load tap-changer or a selector or a pre-selector or a load changeover switch or a reversing switch or a double reversing switch. [11] Electrical equipment with a switch arrangement according to one of claims 1 to 8, wherein - the switch (17) is assigned to the electrical equipment (19) or is installed on or in the electrical equipment (19); and - the safety measure includes or can trigger a separation of the equipment (19) from a power grid (21). [12] Equipment arrangement with an electrical equipment (19) according to claim 11 and a circuit breaker (20) for isolating the equipment from the power grid, wherein the safety measure includes actuation of the circuit breaker (20). [13] Method for the safe operation of a switch arrangement comprising a switch (17) and a drive system for the switch (17), the method comprising - activating a protective circuit (14); - initiating a switching operation of the switch (17) by controlling a power unit (11) after the protective circuit (14) has been activated; - detecting a first error signal via a status contact of a control unit (10) of the drive system; - detecting a second error signal via a status contact of the power section (11) of the drive system; - initiating a safety measure depending on the first and second error signals; and - Deactivation of the protective circuit (14) after the switching process has been successfully completed.

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