Hybrid on-load tap changer

Abstract

The application aims to provide a hybrid on-load tap changer. The hybrid on-load tap changer comprises a first gear circuit, a second gear circuit, a main on-off switch, and a thyristor loop arranged between the first gear circuit and the second gear circuit; the thyristor loop comprises a thyristor and a changeover switch, a first anode of the thyristor is connected to a voltage input end of the hybrid on-load tap changer through the changeover switch, a second anode of the thyristor is connected to a voltage output end of the hybrid on-load tap changer through the main on-off switch, and the thyristor loop is used for switching the current from the first gear circuit to the second gear circuit during gear switching. By arranging the thyristor loop between the first gear circuit and the second gear circuit, the problem of long arc striking and pre-breakdown during current switching is solved.

Description

Technical Field

[0001] This application relates to the field of circuits, and more particularly to a hybrid on-load tap changer. Background Technology

[0002] In new power distribution networks, due to the widespread application of new energy sources such as photovoltaic and wind power, as well as the diversity of loads such as new energy vehicles, users have an increasingly urgent need for distribution transformers with on-load tap changing function.

[0003] Currently, on-load tap changers used in distribution transformers are mainly hybrid solutions combining mechanical switches and thyristors. On-load tap changers for distribution transformers are classified into two types based on the arc-extinguishing medium: oil-based arc-extinguishing and vacuum-based arc-extinguishing. Vacuum on-load tap changers cause current throttling during arc extinguishing, resulting in voltage overshoot, which can severely damage the transformer tap winding insulation. Furthermore, the contact gap in a vacuum interrupter is significantly smaller than that in oil, making short-circuit accidents more likely if vacuum failure occurs, thus requiring extremely high process control. Traditional oil-based arc-extinguishing on-load tap changers, where the arc extinguishing process is completed by mechanical contacts drawing an arc in insulating oil, suffer severe contact erosion after repeated switching. The insulating oil decomposes under the influence of the arc, producing flammable gases and trace metal particles, necessitating regular maintenance of the insulating oil and electrode surfaces. Oil-based arc-extinguishing on-load tap changers generally suffer from several problems, such as high cost, long arc length, and contact pre-breakdown. Summary of the Invention

[0004] One object of this application is to provide a hybrid on-load tap changer.

[0005] According to one aspect of this application, a hybrid on-load tap changer is provided, the hybrid on-load tap changer including a first position circuit, a second position circuit, a main on / off switch, and a thyristor circuit disposed between the first position circuit and the second position circuit; the thyristor circuit includes a thyristor and a changeover switch, the first anode of the thyristor is connected to the voltage input terminal of the hybrid on-load tap changer through the changeover switch, the second anode of the thyristor is connected to the voltage output terminal of the hybrid on-load tap changer through the main on / off switch, and the thyristor circuit is used to transition the current from the first position circuit to the second position circuit when switching positions.

[0006] In some embodiments, the first gear circuit includes a first main load circuit and a first transition circuit, the first transition circuit being connected to the first main load circuit; the second gear circuit includes a second transition circuit and a second main load circuit, the second transition circuit being connected to the second main load circuit; the first gear circuit and the second gear circuit can be connected to the voltage output terminal of the hybrid on-load tap changer via the main on / off switch; the thyristor circuit includes a gate trigger circuit, the gate trigger circuit being connected to the thyristor, the gate trigger circuit including a switching switch, the switching switch being used to turn the thyristor on or off.

[0007] In some embodiments, the first main load circuit has a first stationary contact at one end of the voltage output terminal. When the main on / off switch leaves the first stationary contact, a voltage difference is generated across the two ends of the thyristor. The gate trigger circuit provides a trigger current to the gate of the thyristor so that the thyristor completes the first conduction.

[0008] In some embodiments, the gate triggering circuit includes a first triggering resistor and a second triggering resistor. The first triggering resistor is connected to the gate of the thyristor, and the thyristor is connected to a switching switch through the first triggering resistor and the second triggering resistor.

[0009] In some embodiments, the thyristor circuit further includes a gate protection circuit, which includes a current limiting element, and the gate of the thyristor is connected to the current limiting element through the first trigger resistor.

[0010] In some embodiments, the first transition circuit includes a first transition resistor, the first range circuit has a second stationary contact at the voltage input terminal, and the second range circuit has a third stationary contact at the voltage input terminal. When the thyristor is in the first conduction state, the gate trigger circuit is disconnected by the switching switch so that the thyristor automatically turns off after crossing zero, and the current switches to the first transition circuit. When the current switches to the first transition circuit, the switching switch switches from the second stationary contact to the third stationary contact, and the thyristor is turned on by the switching switch to complete the second conduction of the thyristor. The first transition circuit and the thyristor form a first circulating current.

[0011] In some embodiments, the first transition circuit has a fourth stationary contact at its voltage output terminal, and the second transition circuit has a fifth stationary contact at its voltage output terminal. In the first circulating current state, the main on / off switch switches to the fourth and fifth stationary contacts, disconnecting the thyristor via the switching switch, thus forming a second circulating current between the first and second transition circuits. The second transition circuit includes a second transition resistor, and the second main load circuit has a sixth stationary contact at its voltage output terminal. In the second circulating current state, the switching switch switches from the third stationary contact to the second stationary contact, turning on the thyristor via the switching switch. The current is switched from the first transition circuit to the thyristor, completing the third conduction of the thyristor. When the current switches from the first transition circuit to the thyristor, the thyristor is disconnected by the switching switch, and the current is switched to the second transition circuit. When the current switches to the second transition circuit, the switching switch switches from the second stationary contact to the third stationary contact, and the thyristor is turned on by the switching switch. After the fourth conduction of the thyristor is completed, the thyristor is disconnected by the switching switch, and the current is switched from the thyristor to the second main load circuit.

[0012] In some embodiments, the thyristor circuit includes a buffer circuit connected in parallel with the thyristor, the buffer circuit including an absorption resistor and a capacitor connected in series.

[0013] In some embodiments, the thyristor includes a bidirectional thyristor.

[0014] According to another aspect of this application, the present invention provides an on-load tap changer including a hybrid on-load tap changer as described in any of the preceding claims.

[0015] Compared with existing technologies, this application solves the problems of excessively long arcing and pre-breakdown during current switching by setting a thyristor circuit between the first and second gear circuits. The thyristor circuit includes a changeover switch, with the first anode of the thyristor connected to the voltage input terminal of the hybrid on-load tap changer via the changeover switch, and the second anode of the thyristor connected to the voltage output terminal of the hybrid on-load tap changer via the main on / off switch. The thyristor circuit is used to transition the current from the first gear circuit to the second gear circuit during gear switching. Attached Figure Description

[0016] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0017] Figure 1 This diagram illustrates the structure of a hybrid on-load tap changer according to an embodiment of the present application.

[0018] Figure 2 This illustration shows one of the structural schematic diagrams of a hybrid on-load tap changer in the working state according to an embodiment of this application;

[0019] Figure 3 This is a second schematic diagram showing the structure of a hybrid on-load tap changer in the working state according to an embodiment of this application;

[0020] Figure 4 This is shown as a third schematic diagram of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0021] Figure 5 This is shown as a fourth schematic diagram of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0022] Figure 6 Fifth schematic diagram of a hybrid on-load tap changer in the working state according to an embodiment of this application;

[0023] Figure 7 Sixth schematic diagram of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0024] Figure 8 This is shown as the seventh schematic diagram of a hybrid on-load tap changer in the working state according to an embodiment of this application;

[0025] Figure 9 This is shown as a ninth schematic diagram of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0026] Figure 10 This is shown as a schematic diagram of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0027] Figure 11 This is shown as 11 of a schematic diagram of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0028] Figure 12 This is shown as a schematic diagram (12) of a hybrid on-load tap changer in operation according to an embodiment of this application.

[0029] Figure 13 This is shown as diagram thirteen of a hybrid on-load tap changer in operation according to an embodiment of this application;

[0030] Figure 14 Fourteenth of the schematic diagrams showing the structure of a hybrid on-load tap changer in the working state according to an embodiment of this application;

[0031] Figure 15 This is shown as a schematic diagram (15) of a hybrid on-load tap changer in operation according to an embodiment of this application.

[0032] Figure 16 This is shown as diagram sixteen of a hybrid on-load tap changer in operation according to an embodiment of the present application.

[0033] Figure 17 The status timing diagram of the main on / off switch, changeover switch, and switching switch is shown.

[0034] The meanings of the labels in the figures are as follows:

[0035] 101. Main on / off switch; 201. Thyristor; 202. Switch; 203. First trigger resistor; 204. Second trigger resistor; 301. Changeover switch; 401. First main load circuit; 402. First transition circuit; 403. First transition resistor; 501. Second main load circuit; 502. Second transition circuit; 503. Second transition resistor; 601. First stationary contact; 602. Second stationary contact; 603. Third stationary contact; 604. Fourth stationary contact; 605. Fifth stationary contact; 606. Sixth stationary contact; 701. Current limiting element; 801. Absorption resistor; 802. Capacitor. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0037] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] Figure 1A hybrid on-load tap changer according to one embodiment of this application is illustrated. The hybrid on-load tap changer includes a first tap position circuit, a second tap position circuit, a main on / off switch 101, and a thyristor circuit disposed between the first tap position circuit and the second tap position circuit. The thyristor circuit includes a thyristor 201 and a changeover switch 301. The first anode of the thyristor 201 is connected to the voltage input terminal of the hybrid on-load tap changer through the changeover switch 301, and the second anode of the thyristor is connected to the voltage output terminal of the hybrid on-load tap changer through the main on / off switch 101. The thyristor circuit is used to transition the current from the first tap position circuit to the second tap position circuit during tap position switching. In some embodiments, the thyristor 201 includes a bidirectional thyristor. In some embodiments, by providing a thyristor circuit between the first tap position circuit and the second tap position circuit, the current is transitioned from the first tap position circuit to the second tap position circuit only during current switching, and equipotential is provided. During non-current switching, no current flows through the thyristor 201, and it does not withstand voltage. In some embodiments, the first range circuit has multiple stationary contacts at its voltage output terminal, and the second range circuit has multiple stationary contacts at its voltage output terminal. The main on / off switch enables switching connections between the voltage output terminal and different stationary contacts of the first and second range circuits. For a detailed description of this embodiment, please refer to the corresponding embodiment below, which will not be repeated here. In some embodiments, such as Figure 1 As shown, the first gear circuit includes gear N, and the second gear circuit includes gear N+1.

[0039] In some embodiments, the first gear position circuit includes a first main load circuit 401 and a first transition circuit 402, the first transition circuit 402 being connected to the first main load circuit 401; the second gear position circuit includes a second transition circuit 502 and a second main load circuit 501, the second transition circuit 502 being connected to the second main load circuit 501; the first gear position circuit and the second gear position circuit can be connected to the voltage output terminal of the hybrid on-load tap changer via the main on / off switch 101; the thyristor circuit includes a gate trigger circuit, the gate trigger circuit being connected to the thyristor 201, the gate trigger circuit including a switching switch 202, the switching switch 202 being used to turn the thyristor 201 on or off. In some embodiments, such as Figure 1As shown, the thyristor circuit is disposed between the first tap position circuit and the second tap position circuit. Specifically, the thyristor circuit is disposed between the first transition circuit 402 and the second transition circuit 502. In some embodiments, the moving contact of the main on / off switch 101 includes an arc-shaped moving contact, and the first tap position circuit can be connected to the voltage output terminal through the main on / off switch 101. For example, the main on / off switch 101 can selectively connect the first main load circuit 401, the first transition circuit 402, the second main load circuit 501, the second transition circuit 502 and the voltage output terminal. For a description of the corresponding embodiments, please refer to the following text, which will not be repeated here. In some embodiments, the changeover switch 301 can selectively connect the first tap position circuit and the second tap position circuit. For a description of the corresponding embodiments, please refer to the following text, which will not be repeated here. In some embodiments, the first tap position circuit and the second tap position circuit are respectively connected to the voltage input terminal, and the first tap position circuit and the second tap position circuit can be connected to the voltage output terminal of the hybrid on-load tap changer through the main on / off switch 101.

[0040] In some embodiments, the first main load circuit 401 has a first stationary contact 601 at one end of its voltage output terminal. By controlling the main on / off switch 101 to move away from the first stationary contact 601, a voltage difference is generated across the thyristor 201. The gate trigger circuit provides a trigger current to the gate of the thyristor 201, thereby enabling the thyristor 201 to complete its first conduction. Here, the terms "first conduction" and "second conduction" used in this application are only used to distinguish conduction states at different times. For example, Figure 2 The diagram shows the structure of the on-load switching circuit in its initial state. In the initial state, the main on / off switch 101 is connected to the first stationary contact 601. Current flows from the voltage input terminal through the first main load circuit, and then through the first stationary contact 601 and the main on / off switch 101 to connect to the voltage output terminal. During the current switching process, as... Figure 3 , Figure 4 As shown, the main on / off switch 101 will leave the first stationary contact 601, generating an electric arc. A voltage difference is generated across the two ends of the thyristor 201. The gate trigger circuit provides a trigger current to the gate of the thyristor 201 so that the thyristor 201 completes the first conduction. The current flows from the voltage input terminal through the thyristor 201, and the thyristor 201 is connected to the voltage output terminal through the second anode.

[0041] In some embodiments, such as Figure 1As shown, the gate triggering circuit includes a first trigger resistor 203 and a second trigger resistor 204. The first trigger resistor 203 is connected to the gate of the thyristor 201, and the thyristor 201 is connected to a switching switch 202 through the first trigger resistor 203 and the second trigger resistor 204. In some embodiments, the switching switch 201 turns the thyristor 201 on or off, and the gate triggering circuit provides a trigger current to the thyristor 201 through the first trigger resistor 203 and the second trigger resistor 204 to limit large currents.

[0042] In some embodiments, continue to refer to Figure 1 The thyristor circuit further includes a gate protection circuit, which includes a current limiting element 701. The gate of the thyristor is connected to the current limiting element 701 through the first trigger resistor 203. In some embodiments, the current limiting element 701 includes, but is not limited to, a TVS (Transient Voltage Suppressor).

[0043] In some embodiments, continue to refer to Figure 1 The first transition circuit 402 includes a first transition resistor 403. The first range circuit has a second stationary contact 602 at the voltage input terminal, and the second range circuit has a third stationary contact 603 at the voltage input terminal. When the thyristor 201 is in the first conducting state, the gate trigger circuit is disconnected by the switching switch 202, so that the thyristor 201 automatically turns off after crossing zero, and the current switches to the first transition circuit 402. By controlling the switching switch 301 to switch from the second stationary contact 602 to the third stationary contact 603, the switching switch 202 turns on the thyristor 201, so that the first transition circuit 403 and the thyristor 201 form a first circulating current. Figure 5 As shown, in some embodiments, when the thyristor 201 is in the first conducting state, the gate trigger circuit is disconnected by the switching switch 202, so that the thyristor 201 automatically turns off after crossing zero, and the current switches to the first transition circuit 402; further, as Figure 6 As shown, the selector switch 301 is controlled to switch from the second stationary contact 602 to the third stationary contact 603; further, as... Figure 7 As shown, the switching switch 202 turns on the thyristor 201, completing the second conduction of the thyristor, so that the first transition circuit 403 and the thyristor 201 form a first circulating current. In some embodiments, the first transition circuit 402 is provided with a fourth stationary contact 604 at the voltage output terminal, such as... Figure 5When the thyristor 201 is in the first conducting state, the gate trigger circuit is disconnected by the switching switch 202, so that the thyristor 201 automatically turns off after crossing zero. When the current switches to the first transition circuit 402, the current flows from the voltage input terminal through the first transition circuit 402, the fourth stationary contact 604, the main on / off switch, and connects to the voltage output terminal. Figure 5 , Figure 6 In the indicated state, current flows from the voltage input terminal, through the first transition circuit 402, the fourth stationary contact 604, and the main on / off switch to the voltage output terminal. In some embodiments, such as Figure 7 As shown, when the first transition circuit 403 and the thyristor 201 form a first circulating current, both the first transition circuit 403 and the thyristor 201 are connected to the voltage input terminal, and both the first transition circuit 403 and the thyristor 201 are connected to the voltage output terminal.

[0044] In some embodiments, the first transition circuit 402 is provided with a fourth stationary contact 604 at its voltage output terminal, and the second transition circuit 502 is provided with a fifth stationary contact 605 at its voltage output terminal. When the first transition circuit 402 and the thyristor 201 form a first circulating current state, such as Figure 8 As shown, the main on / off switch 101 is controlled to switch to the fourth stationary contact 604 and the fifth stationary contact 605; furthermore, as... Figure 9 As shown, the switching switch 202 is disconnected, causing the first transition circuit 402 and the second transition circuit 502 to form a second circulating current; the second transition circuit 502 includes a second transition resistor 503, and the second main load circuit 501 is provided with a sixth stationary contact 606 at the voltage output terminal; furthermore, as Figure 10 As shown, when the first transition circuit 402 and the second transition circuit 502 form a second circulating current, the changeover switch 301 is controlled to switch from the third stationary contact 603 to the second stationary contact 602; furthermore, as Figure 11 , Figure 12 As shown, the switching switch 202 controls the thyristor 201 to conduct, switching the current from the first transition circuit 402 to the thyristor 201, completing the third conduction of the thyristor 201 (the current flows through the voltage input terminal, through the thyristor 201, and through the second anode of the thyristor 201 to connect to the voltage output terminal), so that the thyristor 201 and the second transition circuit 502 form a third circulating current; further, as Figure 13 As shown, closing the switching switch 202 switches the current to the second transition circuit (the current flows through the voltage input terminal, through the second transition circuit, and connects to the voltage output terminal); further, as... Figure 14 , Figure 15As shown, the control switch 301 switches from the second stationary contact 602 to the third stationary contact 603, and the switching switch 202 turns on the thyristor 201, completing the fourth conduction of the thyristor, so that the current switches from the second transition current 502 to the thyristor 201; further, as Figure 16 As shown, turning off the thyristor 201 via the switching switch 202 switches the current to the second main load circuit 501.

[0045] In some embodiments, the thyristor circuit includes a buffer circuit connected in parallel with the thyristor, the buffer circuit including an absorption resistor 801 and a capacitor 802 connected in series.

[0046] It will be understood by those skilled in the art that the main on / off switch 101, changeover switch 301, and switching switch 202 can be driven to rotate by a motor. In some embodiments, the motor can be controlled by a controller. For example, the controller is electrically connected to the motor and sends control commands to the motor. In some embodiments, the main on / off switch 101, changeover switch 301, and switching switch 202 can be driven by a motor in conjunction with a corresponding mechanism. It will be understood by those skilled in the art that this solution aims to provide a hybrid on-load tap changer. The specific driving structure of the main on / off switch 101, changeover switch 301, and switching switch 202 is not the inventive point of this solution; a driving structure that can fulfill the control strategy of the main on / off switch 101, changeover switch 301, and switching switch 202 in the above embodiments is sufficient. Figure 17 A timing diagram regarding the control strategy is shown. In this diagram, in each timing line, the upper broken line represents the on state, and the lower broken line indicates the off state. For example, the first stationary contact 601 is on in the initial state, and when the main on / off switch leaves the first stationary contact, the first stationary contact 601 is off. Figure 17 Each timing line in the circuit is the same as or similar to the timing line of the first stationary contact 601, which will not be elaborated here.

[0047] According to another embodiment of this application, an on-load tap-changing transformer is provided, the on-load tap-changing transformer including the hybrid on-load tap changer described in the above embodiments.

[0048] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0049] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A hybrid on-load tap changer, characterized in that, The hybrid on-load tap changer includes a first tap circuit, a second tap circuit, a main on / off switch, and a thyristor circuit disposed between the first tap circuit and the second tap circuit. The thyristor circuit includes a thyristor and a changeover switch. The first anode of the thyristor is connected to the voltage input terminal of the hybrid on-load tap changer through the changeover switch. The second anode of the thyristor is connected to the voltage output terminal of the hybrid on-load tap changer through the main on / off switch. The thyristor circuit is used to transition the current from the first gear circuit to the second gear circuit when switching gears. The first gear circuit includes a first main load circuit and a first transition circuit, with the first transition circuit connected to the first main load circuit; the second gear circuit includes a second transition circuit and a second main load circuit, with the second transition circuit connected to the second main load circuit; the first gear circuit and the second gear circuit can be connected to the voltage output terminal of the hybrid on-load tap changer via the main on / off switch; The thyristor circuit includes a gate trigger circuit connected to the thyristor. The gate trigger circuit includes a switching switch, which turns the thyristor on or off.

2. The hybrid on-load tap changer according to claim 1, characterized in that, The first main load circuit has a first stationary contact at one end of the voltage output terminal. When the main on / off switch leaves the first stationary contact, a voltage difference is generated across the two ends of the thyristor. The gate trigger circuit provides a trigger current to the gate of the thyristor so that the thyristor completes the first conduction.

3. The hybrid on-load tap changer according to claim 2, characterized in that, The gate trigger circuit includes a first trigger resistor and a second trigger resistor. The first trigger resistor is connected to the gate of the thyristor, and the thyristor is connected to a switching switch through the first trigger resistor and the second trigger resistor.

4. The hybrid on-load tap changer according to claim 3, characterized in that, The thyristor circuit also includes a gate protection circuit, which includes a current limiting element. The gate of the thyristor is connected to the current limiting element through the first trigger resistor.

5. The hybrid on-load tap changer according to claim 1, characterized in that, The first transition circuit includes a first transition resistor. The first range circuit has a second stationary contact at the voltage input terminal, and the second range circuit has a third stationary contact at the voltage input terminal. When the thyristor is in the first conduction state, the gate trigger circuit is disconnected by the switching switch so that the thyristor automatically turns off after crossing zero, and the current switches to the first transition circuit. When the current switches to the first transition circuit, the switching switch switches from the second stationary contact to the third stationary contact, and the thyristor is turned on by the switching switch to complete the second conduction of the thyristor. The first transition circuit and the thyristor form a first circulating current.

6. The hybrid on-load tap changer according to claim 5, characterized in that, The first transition circuit is provided with a fourth stationary contact at the voltage output terminal, and the second transition circuit is provided with a fifth stationary contact at the voltage output terminal. In the first circulating current state, the main on / off switch is switched to the fourth and fifth stationary contacts, and the thyristor is disconnected by the switching switch. The first transition circuit and the second transition circuit form a second circulating current. The second transition circuit includes a second transition resistor. The second main load circuit has a sixth stationary contact at the voltage output terminal. In the second circulating current state, the changeover switch switches from the third stationary contact to the second stationary contact, and the thyristor is turned on through the switching switch, so that the current switches from the first transition circuit to the thyristor, completing the third conduction of the thyristor, and the current switches from the first transition circuit to the thyristor. When the current switches from the first transition circuit to the thyristor, the thyristor is turned off through the switching switch, and the current switches to the second transition circuit. When the current switches to the second transition circuit, the changeover switch switches from the second stationary contact to the third stationary contact, and the thyristor is turned on through the switching switch, completing the fourth conduction of the thyristor. Then, the thyristor is turned off through the switching switch, and the current switches from the thyristor to the second main load circuit.

7. The hybrid on-load tap changer according to claim 1, characterized in that, The thyristor circuit includes a buffer circuit connected in parallel with the thyristor, and the buffer circuit includes an absorption resistor and a capacitor connected in series.

8. The hybrid on-load tap changer according to claim 1, characterized in that, The thyristor includes a bidirectional thyristor.

9. An on-load tap-changing transformer, characterized in that, Including the hybrid on-load tap changer as described in any one of claims 1 to 8.

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