On-load tap changer and method for operation

Abstract

The invention relates to an on-load tap changer (1) for switching without disconnection between winding taps (N1... NJ,..., NN) of a control winding (4) of a tap transformer (2), comprising: a selector (5) for preselecting a selected winding tap (NJ) without power; the invention relates to an on-load tap changer (1), comprising a selector (5) for selecting a winding tap (NJ), an on-load switcher (6) for actually switching a load from a current winding tap (NJ-1) to a preselected winding tap (NJ), a safety device (7) being connected in series between the selector (5) and the on-load switcher (6), said safety device being designed to limit a short-circuit current occurring in the on-load tap changer (1) and / or in the control winding (4) in the event of a fault.

Description

Technical Field

[0001] The present invention relates to an on-load tap changer for seamless switching between the winding taps of the regulating winding of a tap changer transformer, and a method for operating the on-load tap changer. Background Technology

[0002] On-load tap changers are known to be used for non-disconnect switching between different winding taps of a tap changer's regulating winding, and thereby for voltage regulation. An on-load tap changer typically includes: a selector for pre-selecting the winding tap to which the tap should be switched during no-power tapping, and an on-load switcher for actually non-disconnect switching from the currently connected winding tap to the new pre-selected winding tap. For no-power tap pre-selection, the selector typically has two movable selector contacts connected to the winding tap. The on-load switcher typically has switching contacts and resistors for actual load switching. The switching contacts are arranged in the main load branch of the on-load switcher and are used to directly connect the winding tap connected via the corresponding selector contacts to the load lead through the main load branch. The resistors are used to limit circulating currents flowing briefly in the on-load switcher during the switching process, and these resistors are also referred to as transfer resistors.

[0003] When an on-load tap changer is not operated as specified, a malfunction may occur. One possible malfunction is a short circuit in the on-load tap changer, more precisely, in the on-load switch, caused by a flashover between the two main load branches. This can lead to a tap short circuit because each of the two main load branches is electrically connected to a tap of the regulating winding via a selector contact. Specifically, this means that the short-circuit current flows through the main load branches and the selector contact, through a regulating stage of the regulating winding of the tap changer transformer.

[0004] To protect transformers from further damage or even destruction in the event of a short circuit, circuit breakers (Leistungsschalter) are installed in the transmission network. These circuit breakers are designed to safely interrupt large currents in the event of a fault. However, circuit breakers require a relatively long time to do this, for example, 50 milliseconds. During this duration, the short-circuit current flows unrestricted through the conductive parts of the on-load tap changer and the transformer, which can potentially cause serious damage to the on-load tap changer and the transformer. This needs to be avoided.

[0005] A device for limiting short-circuit current in such fault conditions is known from patent document DE102020110935B3. This device includes a current sensor and a disconnecting element arranged in the first current line of an on-load tap changer. A current-limiting element is arranged in parallel with the disconnecting element. The current sensor is configured to transmit a first measurement signal representing the current measured in the first current line of the on-load tap changer to the control device of the device. The disconnecting element can be operated by the control device to interrupt the current flow in the first current line of the on-load tap changer, thereby diverting the flow current to the current-limiting element. A disadvantage of this known solution is the need for additional monitoring measures in the current line, particularly sensor elements, to identify the short-circuit current and subsequently actively trigger protection, i.e., trigger the disconnecting element, via the control unit. Another disadvantage stems from the requirements of the disconnecting element itself. Since a very fast response (within 0.1 to 1.0 milliseconds) is required in fault conditions to prevent further damage to the transformer, semiconductor switching elements are particularly suitable as disconnecting elements. These components are very sensitive and therefore prone to failure. Summary of the Invention

[0006] Against this backdrop, the present invention presents the technical solution of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0007] According to a first aspect, the present invention provides an on-load tap changer for seamless switching between winding taps of a tap changer transformer's regulating winding. The on-load tap changer includes: a selector for pre-selecting a selected winding tap of the unpowered regulating winding; and an on-load switch for actually switching the load from the current winding tap to the winding tap pre-selected by the selector. A safety device is connected in series between the selector and the on-load switch, configured to limit short-circuit currents occurring in the on-load tap changer (more specifically, the selector and / or the on-load switch and / or the safety device) and / or the regulating winding in the event of a fault. Thus, damage to the on-load tap changer and the transformer can be avoided before a circuit breaker triggers and safely interrupts the fault current.

[0008] According to a preferred embodiment of an on-load tap changer, the selector has a first selector arm and a second selector arm, and the on-load tap changer has a first switching side and a second switching side. The first switching side is electrically connected to the first selector arm via a first current path, and the second switching side is electrically connected to the second selector arm via a second current path. Furthermore, a safety device has a first resistor and a second resistor. The first resistor can be connected to and disconnected from the first current path by means of a first switching element arranged in parallel with the first resistor, and the second resistor can be connected to and disconnected from the second current path by means of a second switching element arranged in parallel with the second resistor. In other words, the resistors can be connected or disconnected by switching elements.

[0009] Therefore, according to the present invention, the resistor in the safety device is used to limit the short-circuit current that occurs in the event of a fault.

[0010] According to a preferred embodiment, the resistor in the safety device is constructed as an ohmic resistor.

[0011] Preferably, the first switching element and the second switching element are configured as mechanical switching contacts.

[0012] Particularly preferably, the first and second switching elements are configured as vacuum switching transistors.

[0013] According to another embodiment, the first switching element and the second switching element are configured as semiconductor switching elements.

[0014] According to one implementation, during the switching process of an on-load tap changer, either a first resistor is connected to a first current path or a second resistor is connected to a second current path. In other words, indirect or passive protection against short-circuit current is provided throughout the switching process, because one of the two resistors in the safety device is always connected to the current loop. Therefore, active protection triggering is not required. This eliminates the need for additional monitoring measures, such as current sensors in the current path, to identify fault conditions.

[0015] According to another embodiment, during the switching process, current temporarily flows through the first resistor and / or the second resistor. Therefore, at least one resistor of the safety device is not only connected during the switching process but is also actively integrated into the switching process. This has the advantage that, because the current load is distributed among the resistors in the on-load switch and the safety device, the specifications of the resistors in the on-load switch can be designed to be smaller. This results in cost savings.

[0016] According to another implementation, when no current flows through the first selector arm, the first resistor is connected to or is connected to the first current path, and when no current flows through the second selector arm, the second resistor is connected to or is connected to the second current path.

[0017] According to a preferred embodiment, when the on-load tap changer is in a first steady-state state (in which the on-load tap changer is in contact with the current winding tap), the second resistor is connected to or is connected to the second current path, and when the on-load tap changer is in a second steady-state state (in which the on-load tap changer is in contact with a new winding tap), the first resistor is connected to or is connected to the first current path. In other words, when the on-load tap changer is operating in a steady-state state, indirect or passive protection against short-circuit current is provided because one of the two resistors in the safety device is always connected to the current loop. Therefore, active triggering of protection is not required. This eliminates the need for additional monitoring measures, such as current sensors in the current path, for identifying fault conditions.

[0018] According to another embodiment, the safety device has a first continuous main contact and a second continuous main contact, the first continuous main contact being arranged in parallel with a first resistor and a first switching element and configured to guide a continuous current in the steady state of an on-load tap changer, and the second continuous main contact being arranged in parallel with a second resistor and a second switching element and configured to guide a continuous current in the steady state of an on-load tap changer.

[0019] According to another embodiment, the on-load switch has a third continuous main contact and a fourth continuous main contact. The third continuous main contact is assigned to a first switching side of the on-load switch and is configured to guide a continuous current in the steady state of the on-load tap changer. The fourth continuous main contact is assigned to a second switching side of the on-load switch and is configured to guide a continuous current in the steady state of the on-load tap changer.

[0020] According to a preferred embodiment, in a first steady state, current flows through the first continuous main contact and the third continuous main contact, and in a second steady state, current flows through the second continuous main contact and the fourth continuous main contact.

[0021] According to another embodiment, the safety device, on-load switch and / or selector are mechanically coupled through a common drive unit, such that the switching elements and / or selector arms of the safety device and on-load switch are operated in association with each other.

[0022] According to a preferred embodiment, the common drive unit includes: a first transmission mechanism assigned to a safety device; a second transmission mechanism assigned to an on-load switch and / or selector; a coupling shaft, through which the first and second transmission mechanisms are mechanically connected to each other; a drive shaft; and a common motor driver. The motor driver is operated by a control unit. The control unit can be configured arbitrarily. For example, the control unit can be configured as a voltage regulator or a control center. Depending on the configuration, the communication connection with the drive unit can be wired or wireless.

[0023] In another embodiment, the safety device and the on-load switch and / or selector are electronically coupled through a common control unit, such that the switching elements are operated in relation to each other. The common control unit can be configured arbitrarily. For example, the control unit can be configured as a voltage regulator or a control center.

[0024] According to a preferred embodiment, the safety device operates via a first driver, a first drive shaft, and a first transmission mechanism, and the on-load switch and / or selector operates via a second driver, a second drive shaft, and a second transmission mechanism. The first and second drivers are operated in association with each other via a common electronic control unit. Depending on the configuration, the communication connection with the first and second drivers can be implemented as a wired connection or a wireless connection.

[0025] According to a particularly preferred embodiment, the mechanical and / or electronic coupling of the safety device and the on-load switch is configured such that the first continuous main contact and the third continuous main contact are simultaneously disconnected, and the second continuous main contact and the fourth continuous main contact are simultaneously disconnected.

[0026] According to another embodiment, the safety device is arranged in a first housing filled with an insulating medium, the on-load switch is arranged in a second housing filled with an insulating medium, and the first housing is arranged inside and / or outside the transformer housing, and the second housing is arranged inside and / or outside the transformer housing.

[0027] According to a preferred embodiment, the first housing and the second housing are arranged side by side inside the transformer housing.

[0028] According to a second aspect, the present invention provides a method for operating an on-load tap changer for seamless switching between winding taps of a tap changer transformer's regulating winding. The on-load tap changer includes: a selector for pre-selecting a selected winding tap without power; an on-load switcher for actually switching the load from the current winding tap to the pre-selected winding tap; and a safety device connected in series between the selector and the on-load switcher. According to the invention, the on-load tap changer switches from a first steady-state state (in which the on-load tap changer is in contact with the current winding tap) to a second steady-state state (in which the on-load tap changer is in contact with a new winding tap). The safety device is configured to limit short-circuit currents occurring in the on-load tap changer and / or the regulating winding in the event of a fault.

[0029] According to one embodiment, the safety device is configured to limit, in a steady state, the short-circuit current occurring in the on-load tap changer and / or regulating winding and / or transformer under fault conditions.

[0030] According to another embodiment, the safety device is configured to limit the short-circuit current that may occur in the on-load tap changer and / or regulating winding and / or transformer in the event of a fault during switching.

[0031] According to another embodiment, the selector has a first selector arm and a second selector arm; the on-load switch has a first switching side and a second switching side, the first switching side being electrically connected to the first selector arm via a first current path, and the second switching side being electrically connected to the second selector arm via a second current path; and the safety device has a first resistor and a second resistor, the first resistor being able to access and exit the first current path by means of a first switching element arranged in parallel with the first resistor, and the second resistor being able to access and exit the second current path by means of a second switching element arranged in parallel with the second resistor; wherein, when switching from a first steady-state state to a second steady-state state, the second resistor has been accessed or is accessed by the second current path, the load current in the on-load switch is switched from the first switching side of the on-load switch to the second switching side, and the first resistor is accessed by the first current path.

[0032] According to another implementation, when switching from the second steady state to the first steady state, the first resistor has been connected to or has been connected to the first current path, the load current in the on-load switch is switched from the second switching side of the on-load switch to the first switching side, and the second resistor is connected to the second current path.

[0033] According to another embodiment, the safety device has a first continuous main contact and a second continuous main contact, the first continuous main contact being arranged in parallel with a first resistor and a first switching element, the second continuous main contact being arranged in parallel with a second resistor and a second switching element, and the on-load switch having a third continuous main contact and a fourth continuous main contact, the third continuous main contact being assigned to a first switching side of the on-load switch, and the fourth continuous main contact being assigned to a second switching side of the on-load switch; wherein, when switching from a first steady-state state to a second steady-state state, when the second resistor is connected to the second current path, or after the second resistor is connected to the second current path, the first continuous main contact and the third continuous main contact are simultaneously disconnected.

[0034] According to another implementation, when switching from the second steady state to the first steady state, when the first resistor is connected to the first current path, or after the second resistor is connected to the second current path, the second continuous main contact and the fourth continuous main contact are simultaneously disconnected.

[0035] Other design forms and implementations of this method are directly derived from various implementations of on-load tap changers. In particular, to implement this method, the single or multiple components and / or arrangements described for on-load tap changers can be implemented accordingly.

[0036] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments. Components that are identical, functionally identical, or have the same function may be labeled with the same reference numerals. In some cases, identical or functionally identical components are described only with respect to their first appearance in the accompanying drawing. They are not necessarily repeated in subsequent drawings. Attached Figure Description

[0037] Figure 1 An exemplary embodiment of a known on-load tap changer is illustrated in schematic diagram;

[0038] Figure 2 A first exemplary embodiment of the on-load tap changer of the present invention is illustrated in schematic diagram;

[0039] Figures 3a to 3h Show Figure 2 An exemplary switching process for an on-load tap changer according to the present invention;

[0040] Figure 4 An exemplary and schematic arrangement in a tap changer is shown, according to an exemplary embodiment of an on-load tap changer of the present invention;

[0041] Figure 5 This illustrates an exemplary and schematic arrangement in a tap changer according to another exemplary embodiment of the on-load tap changer of the present invention.

[0042] The accompanying drawings illustrate only embodiments of the present invention, but are not intended to limit the invention to the illustrated embodiments. Detailed Implementation

[0043] exist Figure 1 The diagram schematically illustrates an exemplary embodiment of an on-load tap changer 1, known in the prior art, for a tap transformer 2. The tap transformer 2 has a main winding 3 and an adjusting winding 4, the adjusting winding having different winding taps N1, ..., N... J ..., N N These winding taps are connected or disconnected via an on-load tap changer 1. For this purpose, the on-load tap changer 1 includes a selector 5 and an on-load switch 6. The selector can be connected to different winding taps N1, ..., N2 of the adjusting winding 4 via two movable selector contacts. J ..., N N Upon contact, the on-load switcher physically switches the load from the currently connected winding tap to a new, pre-selected winding tap. In on-load switcher 6... Figure 1 In the position shown, the load current flows from the currently connected winding tap N. j+1 The current flows to the load lead 33 through the corresponding selector contact and on-load switch 6.

[0044] exist Figure 2The diagram schematically illustrates a first exemplary embodiment of an on-load tap changer according to the present invention. The on-load tap changer 1 is used to tap the winding tap N of the regulating winding 4 of the tap transformer 2. J N J+1 Seamless switching between them.

[0045] On-load tap changer 1 includes a selector 5 having a first selector arm 8 and a second selector arm 9, the first selector arm being connected to the winding tap N of the regulating winding 4. J Contact, the second selector arm and the winding tap N of the adjusting winding 4. J+1 Contact. Furthermore, the on-load tap changer 1 also includes an on-load switch 6 having a first switching side 10 and a second switching side 11. The first switching side 10 is electrically connected to a first selector arm 8 via a first current path 12, and the second switching side 11 is electrically connected to a second selector arm 9 via a second current path 13.

[0046] A safety device 7 is connected in series between the selector 5 and the on-load switch 6. This safety device is configured to limit the short-circuit current in the on-load tap changer 1 and / or the tap transformer 2, more specifically, the regulating winding 4, in the event of a fault. The safety device 7 is constructed in two parts. The safety device includes a first ohmic resistor 14, which can be connected to and from a first current path 12 by means of a first switching element 16 arranged in parallel with the ohmic resistor 14. A first continuous main contact 18 is arranged in parallel with the first ohmic resistor 14 and the first switching element 16 and is configured to guide a continuous current in the steady-state state of the on-load tap changer 1. Depending on which steady-state state the on-load tap changer 1 is in or which switching step it is in during switching, an electrical connection can be selectively established between the first selector arm 8 and the load lead 33, which extends through the first ohmic resistor 14 and / or the first switching element 16 and / or the first continuous main contact 18 through the first current path 12 and the first switching side 10 of the on-load switch 6. Furthermore, the safety device 7 includes a second ohmic resistor 15, which can be connected to and disconnected from the second current path 13 via a second switching element 17 arranged in parallel with the resistor 15. A second continuous main contact 19 is arranged in parallel with the second ohmic resistor 15 and the second switching element 17 and is configured to guide a continuous current in the steady-state state of the on-load tap changer 1. Depending on the steady-state state of the on-load tap changer 1 or the switching step during switching, an electrical connection can be selectively established between the second selector arm 9 and the load lead 33, extending via the second ohmic resistor 15 and / or the second switching element 17 and / or the second continuous main contact 19 through the second current path 13 and the second switching side 11 of the on-load switcher 6.

[0047] According to this exemplary embodiment, the first switching element 16 and the second switching element 17 are configured as vacuum switching transistors 16 and 17. In principle, however, other mechanical switching elements and / or semiconductor switching elements may also be used.

[0048] To implement switching, the on-load tap changer 6 has multiple switching contacts and resistors. However, the specific circuit arrangement of the on-load tap changer is not critical to the implementation of the present invention. Therefore, the implementation of the on-load tap changer 6 described below should only be interpreted as exemplary, and in principle, other suitable and known on-load tap changer arrangements can also be used to implement the present invention. According to this exemplary embodiment of the present invention, the first switching side 10 of the on-load tap changer 6 is provided with a third continuous main contact 20, and the second switching side 11 of the on-load tap changer 6 is provided with a fourth continuous main contact 21. The continuous main contacts 20 and 21 are configured to conduct continuous current guidance in the steady state of the on-load tap changer 1 in a manner known per se. In addition, the first switching side 10 has a first vacuum switch tube 34 and a first switching resistor 36 connected in parallel with the first vacuum switch tube. Together with a second vacuum switch tube 35 connected in series. Similarly, the second switching side 11 has a third vacuum switch tube 37 and a fourth vacuum switch tube 38 connected in series with a second switching resistor 39 connected in parallel with the third vacuum switch tube. In addition, a first mechanical switch 40 is provided between the electrical connection portion of the two vacuum switch tubes 34 and 35 on the first switching side 10 and the load lead 33, and similarly, a second mechanical switch 41 is provided between the electrical connection portion of the two vacuum switch tubes 37 and 38 on the second switching side 11 and the load lead 33.

[0049] exist Figure 2 In the middle, the on-load tap changer 1 is in a steady state. In this steady state, the on-load tap changer and the winding tap N are in a stable state. j Connection. Accordingly, the load current flows from the regulating winding 4 through the winding tap N. j The load current flows into the safety device 7 via the first selector arm 8. In the safety device 7, the load current continues through the continuous main contact 18 and the first vacuum switch tube 16, and from there flows into the first switching side 10 of the on-load tap changer 6 via the first current path 12. There, the load current flows to the load lead 33 via the third continuous main contact 20, the vacuum switch tube 34, and the first mechanical switch 40. If a fault occurs in the steady-state condition of the on-load tap changer 1, the second ohmic resistor 15 is connected and can limit the short-circuit current due to the fault. Therefore, in the steady-state condition of the on-load tap changer, this protection is always passively present and does not require additional activation by a triggering mechanism. Similarly, in the second steady-state condition, i.e. at winding tap N... J+1 When connected and no current flows through the first selector arm 8, the first ohmic resistor 14 of the safety device 7 is passively connected.

[0050] exist Figures 3a to 3h In, it is shown Figure 2 An exemplary switching process for an on-load tap changer according to the present invention. From Figure 2 Starting from the steady-state position in the first switching step (which is in the steady-state position in the first switching step), Figure 3a In the step shown in the diagram, the first continuous main contact 18 in the safety device 7 and the third continuous main contact 20 in the on-load switch 6 are simultaneously disconnected, and the second mechanical switch 41 of the on-load switch 6 is simultaneously closed. Preferably, the disconnection of the continuous main contacts 18 and 20 is achieved by mechanical coupling via a common drive unit and / or by electronic coupling via a common control unit. From this point onward, the load current flows only through the first vacuum switch tube 16 in the safety device 7 and through the first vacuum switch tube 34 in the on-load switch 6. In the next step (see...), Figure 3b In the process, the first vacuum switch 34 is also disconnected. As a result, the load current is commutated in the on-load switch 6 to the first switching resistor 36 and the second vacuum switch 35. Subsequently, in the next step, the fourth vacuum switch 38 of the on-load switch 6 is closed (see...). Figure 3c And the loop current flows from the winding tap N. J The return flow passes through the first selector arm 6, the first vacuum switch tube 16 of the safety device 7, the first current path 12, the first switching resistor 36, the second vacuum switch tube 35, and the first mechanical switch 40 of the on-load switch 6. The return flow then passes through the second mechanical switch 41, the fourth vacuum switch tube 38, the second switching resistor 39, and the second current path 13, and finally through the ohmic resistor 15 of the safety device 7 and the second selector arm 9 to enter the new winding tap N to which the switch should be made. J+1 In this switching step, the second ohm resistor 15 is used to limit the current. In subsequent steps (see...) Figure 3d Disconnect the second vacuum switch tube 35 of the on-load switch 6. From now on, the load current will only flow through the new winding tap N. J+1 The second selector arm 8, the second ohmic resistor 15 of the safety device 7, and from there through the second current path 13 flow into the second switching side 11 of the on-load switch 6, where the current continues through the second transfer resistor 39, the fourth vacuum switch tube 38, and the second mechanical switch 41 to the load lead 33. In the next step (which is in Figure 3e As shown in the diagram, the third vacuum switch 37 of the on-load switch 6 is closed. This allows the current in the on-load switch 6 to now flow through the third vacuum switch 37 and the second mechanical switch 41 to the load lead 33. In subsequent steps (see...), Figure 3fThe fourth continuous main contact 21 of the on-load switch 6 is closed, and the first mechanical switch 40 is opened. Therefore, the load current in the on-load switch now flows to the load lead 33 through the third vacuum switch tube 37, the fourth continuous main contact 21, and the second mechanical switch 41. Subsequently, the first vacuum switch tube 16 of the safety device 7 is opened, and simultaneously the second vacuum switch tube 17 of the safety device 7 is closed (see...). Figure 3g Now, the load current no longer flows through the second ohmic resistor 15 in the safety device 7, but instead flows through the second vacuum switch tube 17. In the last step (which in Figure 3h As shown in the diagram, the second continuous main contact 19 of the safety device 7 is closed. This brings the on-load tap changer 1 to a new steady-state state, and the switching process is complete. Now, the load current flows from the winding tap N. J+1 The current flows through the second selector arm 9, the second vacuum switch tube 17 of the safety device 7, and the second continuous main contact 19, into the second switching side 11 of the on-load tap changer 6 via the second current path 13, and then through the third vacuum switch tube 37, the fourth continuous main contact 21, and the second mechanical switch 41 to the load lead 33. If a fault occurs in this steady-state condition of the on-load tap changer 1, the first ohmic resistor 14 is connected and can limit the short-circuit current caused by the fault.

[0051] As can be seen from the described switching procedure, the second ohmic resistor 15 of the safety device 7 is integrated into the normal switching process of the on-load tap changer 1 (see...). Figure 3c , Figure 3d , Figure 3e , Figure 3f Similarly, the first ohmic resistor 14 of the safety device 7 during the reverse switching process, i.e., for example, from the winding tap N... J+1 Switch to winding tap N J The safety device 7's ohmic resistors 14 and 15 are integrated into the specified switching process of the on-load tap changer 1. The advantage of this is that the switching resistors 36 and 39 of the on-load switch 6 can be designed to a smaller size, thereby saving costs.

[0052] In principle, this implementation means that, not only during the steady-state state of the on-load tap changer 1 but also during the switching process, either the first ohmic resistor 14 or the second ohmic resistor 15 of the safety device 7 is connected, thereby providing passive protection for the on-load tap changer 1 and the transformer 2. Figure 2 and Figures 3a to 3f The switching process in the switching direction shown is as follows: Figure 2 as well as Figures 3a to 3f In the position or switching step shown, the second ohmic resistor 15 is connected, and Figure 3g and Figure 3hIn the position or switching step shown, the first ohmic resistor 14 is connected. In the opposite switching direction, the connections of ohmic resistors 14 and 15 are reversed accordingly.

[0053] exist Figure 4 The diagram illustrates an exemplary and schematic arrangement of an on-load tap changer 1 according to the present invention within a tap transformer 2. A safety device 7 is arranged in a first housing 30 filled with an insulating medium (not shown), and an on-load switch 6 is arranged in a second housing 31 filled with an insulating medium (not shown). A selector 5 is located directly below the on-load switch 6. The first housing 30 and the second housing 31 are arranged side-by-side within a transformer housing 32, also filled with an insulating medium (not shown), and are respectively mounted on the transformer housing 32 via fixing flanges 42. The safety device 7, the on-load switch 6, and the selector 5 are mechanically coupled by a common drive mechanism. This drive mechanism includes: a first transmission mechanism 26 assigned to the safety device 7; a second transmission mechanism 27 assigned to the on-load switch 6 and the selector 5; a coupling shaft 28 mechanically connecting the first transmission mechanism 26 and the second transmission mechanism 27; and a drive shaft 29 mechanically connecting a drive unit 22 to the first transmission mechanism 27. Accordingly, a common drive unit 22 is provided, which operates not only the safety device 7 but also the on-load switch 6 and the selector 5 via a drive shaft 29, a coupling shaft 28, and two transmission mechanisms 26 and 27. The drive unit 22 is operated by a control unit 23.

[0054] exist Figure 5 The image shows an exemplary and schematic arrangement of another exemplary embodiment of the on-load tap changer 1 according to the present invention in the tap changer transformer 2. Regarding... Figure 5 The embodiments shown herein refer in a similar manner to the preceding description. Figure 4 The embodiments shown are described below, and only the differences are explained below. Figure 5 In an exemplary embodiment, safety device 7, on-load switch 6, and selector 5 are electronically coupled via control unit 23. Control unit 23 operates a first driver 24 and a second driver 25 in association with each other. The first driver is mechanically connected via a first drive shaft 43 to a first transmission mechanism 26 assigned to safety device 7, and the second driver is mechanically connected via a second drive shaft 44 to a second transmission mechanism 27 assigned to on-load switch 6 and selector 5.

[0055] The present disclosure and its numerous advantages are to be understood through the above description. Furthermore, it will be apparent that various changes can be made to the form, construction, and arrangement of the components without departing from the disclosed technical solution or abandoning all substantial advantages. The described embodiments are merely illustrative, and these changes are covered by the following claims. Moreover, it should be understood that the present invention is defined by the following claims.

[0056] Figure label:

[0057] 1 On-load tap changer

[0058] 2 tap changer

[0059] 3 2 main winding

[0060] 4 2 Adjustment winding

[0061] 5 Selectors

[0062] 6 On-load switch

[0063] 7 Safety devices

[0064] 8 First Selector Arm

[0065] 9 Second Selector Arm

[0066] 10 6 First switching side

[0067] 11 6 Second switching side

[0068] 12 First Current Path

[0069] 13 Second Current Path

[0070] 14.7 First Ohm Resistance

[0071] 15 7 second ohm resistor

[0072] 16 7 First switching element

[0073] 17 7 Second switching element

[0074] 18 7 First Continuous Main Contact

[0075] 19 7 Second Continuous Main Contact

[0076] 20 6 Third continuous main contact

[0077] 21 6 Fourth Continuous Main Contact

[0078] 22 drive units

[0079] 23 Control Unit

[0080] 24 7 drive

[0081] 25 5 and 6 drives

[0082] 26 First transmission mechanism

[0083] 27 Second transmission mechanism

[0084] 28 Coupled Shafts

[0085] 29 22 drive shaft

[0086] 30 First shell

[0087] 31 Second shell

[0088] 32 Transformer housing

[0089] 33 Load Leads

[0090] 34 6 First vacuum switch tube

[0091] 35 6 Second vacuum switch tube

[0092] 36 6 First adapter resistor

[0093] 37 6 Third vacuum switch tube

[0094] 38 6 fourth vacuum switch tube

[0095] 39 6 Second adapter resistor

[0096] 40 6 First mechanical switch

[0097] 41 6 Second mechanical switch

[0098] Fixed flanges 42, 30, and 31

[0099] 43 First drive shaft

[0100] 44 Second drive shaft

Claims

1. A winding tap (N1...N) for use in the regulating winding (4) of a tap transformer (2) J , ..., N N An on-load tap changer (1) that allows for seamless switching between different locations, the on-load tap changer comprising: For power pre-selection of selected winding taps (N) J Selector (5); Used to tap the load off the winding (N) as it is currently in operation. J-1 Actual switching to the pre-selected winding tap (N) J On-load switch (6), A safety device (7) is connected in series between the selector (5) and the on-load switch (6), which is configured to limit the short-circuit current in the on-load tap changer (1) and / or the regulating winding (4) in the event of a fault.

2. The on-load tap changer (1) according to claim 1, wherein, The selector (5) has a first selector arm (8) and a second selector arm (9); The on-load switch (6) has a first switching side (10) and a second switching side (11). The first switching side is electrically connected to the first selector arm (8) through a first current path (12), and the second switching side is electrically connected to the second selector arm (9) through a second current path (13). The safety device (7) has: - A first resistor (14) that can be connected to and disconnected from a first current path (12) by means of a first switching element (16) arranged in parallel with the first resistor (14); and - A second resistor (15) that can be connected to and disconnected from a second current path (13) by means of a second switching element (17) arranged in parallel with the second resistor (15).

3. The on-load tap changer (1) according to claim 2, wherein, During the switching process of the on-load tap changer (1), either the first resistor (14) is connected to the first current path (12), or the second resistor (15) is connected to the second current path (13).

4. The on-load tap changer (1) according to any one of claims 2 or 3, wherein, During the switching process, current temporarily flows through the first resistor and / or the second resistor (12, 15).

5. The on-load tap changer (1) according to any one of claims 2 to 4, wherein, When no current flows through the first selector arm (8), the first resistor (14) is connected or is connected to the first current path (12); When no current flows through the second selector arm (9), the second resistor (15) is connected or is connected to the second current path (13).

6. The on-load tap changer (1) according to any one of claims 2 to 5, wherein, The safety device (7) has: The first continuous main contact (18) is arranged in parallel with the first resistor (14) and the first switching element (16) and is configured to guide continuous current in the steady state of the on-load tap changer (1). and The second continuous main contact (19) is arranged in parallel with the second resistor (15) and the second switching element (17) and is configured to guide continuous current in the steady state of the on-load tap changer (1).

7. The on-load tap changer (1) according to any one of claims 2 to 6, wherein, The on-load switch (6) has: The third continuous main contact (20) is assigned to the first switching side (10) of the on-load switch (6) and is configured to guide a continuous current in the steady state of the on-load tap changer (1). and The fourth continuous main contact (21) is assigned to the second switching side (11) of the on-load switch (6) and is configured to guide a continuous current in the steady state of the on-load tap changer (1).

8. The on-load tap changer (1) according to any one of claims 2 to 7, wherein, The safety device (7) and the on-load switch (6) are mechanically coupled by a common drive unit (22) so that the switching elements (16, 17, 18, 19, 20, 21, 34, 35, 37, 38) are operated in relation to each other.

9. The on-load tap changer (1) according to any one of claims 2 to 7, wherein, The safety device (7) and the on-load switch (6) are electronically coupled through a common control unit (23) so that the switching elements (16, 17, 18, 19, 20, 21, 34, 35, 37, 38) are operated in relation to each other.

10. The on-load tap changer (1) according to any one of claims 1 to 9, wherein, The safety device (7) is arranged in the first housing (30). The on-load switch (6) is arranged in the second housing (31). The first housing (30) is arranged inside and / or outside the transformer housing (32). The second housing (31) is arranged inside the transformer housing (32) and / or outside the transformer housing.

11. A method for operating an on-load tap changer (1), the on-load tap changer being used to tap the winding taps (N1...N) of the regulating winding (4) of a tap transformer (2). J , ..., N N Seamless switching is performed between () and () in which, On-load tap changer (1) includes: a winding tap (N) for no-power preselection of the selected circuit. J Selector (5); used to remove the load from the current winding tap (N) J-1 Actual switching to the pre-selected winding tap (N) J The on-load switch (6) and the safety device (7) connected in series between the selector (5) and the on-load switch (6). in, From the on-load tap changer (1), contact the winding tap (N) so far. J-1 The first steady-state state of the switch is switched to the on-load tap changer (1) to contact the new winding tap (N). J The second steady state of ) The safety device (7) is configured to limit the short-circuit current that occurs in the on-load tap changer (1) and / or regulating winding (4) under fault conditions.

12. The method according to claim 11, wherein, The selector (5) has a first selector arm (8) and a second selector arm (9); The on-load switch (6) has a first switching side (10) and a second switching side (11). The first switching side is electrically connected to the first selector arm (8) through a first current path (12), and the second switching side is electrically connected to the second selector arm (9) through a second current path (13). The safety device (7) has a first resistor (14) and a second resistor (15). The first resistor can be connected to and disconnected from a first current path (12) by means of a first switching element (16) arranged in parallel with the first resistor (14). The second resistor can be connected to and disconnected from a second current path (13) by means of a second switching element (17) arranged in parallel with the second resistor (15). Specifically, when switching from the first steady-state state to the second steady-state state, The second resistor (15) has been connected or has been connected to the second current path (13); The load current in the on-load switch (1) is switched from the first switching side (10) of the on-load switch (6) to the second switching side (11); The first resistor (14) is connected to the first current path (12).

13. The method according to claim 11, wherein, The safety device (7) has a first continuous main contact (18) and a second continuous main contact (19). The first continuous main contact is arranged in parallel with the first resistor (14) and the first switching element (16), and the second continuous main contact is arranged in parallel with the second resistor (15) and the second switching element (17). The on-load switch (6) has a third continuous main contact (20) and a fourth continuous main contact (21), the third continuous main contact being assigned to the first switching side (10) of the on-load switch (6), and the fourth continuous main contact being assigned to the second switching side (11) of the on-load switch (6). When the second resistor (15) is connected to the second current path (13) or after the second resistor (15) is connected to the second current path (13), the first continuous main contact (18) and the third continuous main contact (20) are simultaneously disconnected.

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