A vacuum on-load tap changer double resistance transition circuit and voltage regulation method

Abstract

The present invention discloses a double-resistance transition circuit of a vacuum on-load tap changer and a voltage regulation method. The transition circuit comprises: a first main contact MC1, a second main contact MC2, a first auxiliary vacuum contact V1, a second auxiliary vacuum contact V3, a main vacuum contact V2, a first switch Z1, a second switch Z2, a first transition resistor R1 and a second transition resistor R2. The present invention designs two auxiliary vacuum contact branches, and the task of cutting off the circulating current is taken turns by two auxiliary vacuum contacts. The switching procedure is symmetrical, so that the burning of the two auxiliary vacuum contacts is completely consistent. Compared with the current transition circuit of "single main vacuum contact, single auxiliary vacuum contact" structure, the switching capacity of the main vacuum contact and the auxiliary vacuum contact can be balanced. At the same time, two transition resistors are designed to work in rotation to solve the problem that the temperature of the transition resistor is too high due to the heating of the single transition resistor, resulting in the decomposition and gas production of transformer oil and the reduction of insulation performance, thereby improving the electrical life of the entire vacuum on-load tap changer.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and more specifically, to a vacuum on-load tap changer double-resistance transition circuit and a voltage regulation method. Background Art

[0002] The on-load tap changer is a switching device that provides a constant voltage for the transformer when the load changes. Its basic principle is to switch between the taps in the transformer winding without interrupting the load current, thereby changing the number of turns of the winding, that is, the voltage ratio of the transformer, and finally achieving the purpose of voltage regulation. At present, the on-load tap changers configured in the transformers of rectification, smelting, and railway traction are mostly fast resistor switching, and work on the principle that the arc contact system extinguishes the arc when the current passes through the zero point. This switching principle is particularly serious for the tap changer with frequent switching of the transformer, the failure rate of the switch is high, and the carbonization speed of the oil is fast, which increases the daily maintenance for the power supply department. The vacuum on-load tap changer mainly relies on the vacuum tube of the switching switch to achieve arc extinguishing, and the arc and hot gas are not exposed; the oil in the oil chamber of the tap changer will not be carbonized and polluted, and the oil does not need to be purified; the burning and corrosion of the contacts in the vacuum tube can be minimized. The on-load tap changer is mainly composed of a switching switch, a conversion selector, and an electric mechanism.

[0003] The on-load tap changer needs a transition circuit and a selection circuit for load switching. Different voltage regulation methods require different voltage regulation circuits. Therefore, the circuit of the on-load tap changer consists of three parts: a transition circuit, a selection circuit, and a voltage regulation circuit. The transition circuit is a series resistance circuit across the tap points. The corresponding mechanism is a switching switch or a selection switch. It is a tap changer for changing transformer windings under power. The tap changer uses the principle of the transition circuit to realize the tap change operation. According to the number of transition circuit resistors, there are single resistors, double resistors, four resistors or multiple resistors. According to the contact break, there are single break, double break, etc., which can be combined to form a variety of transition circuits. The transition circuit and the switching procedure have different effects on the contact task of the switching switch. Whether the arc can be reliably extinguished within the first half cycle depends largely on the required switching task.

[0004] The arc contact without transition resistor in the on-load tap changer is the main on-off contact, which is only responsible for breaking the load current; the arc contact with transition resistor is the auxiliary contact, which is only responsible for breaking the internal circulating current. According to the experience of UHV DC engineering, the load current of the single-column winding of the commutation transformer is generally 500-600A, and the internal circulating current flowing through the transition resistor R is about 900-1000A. Since the internal circulating current on the auxiliary vacuum contact is significantly greater than the load current, after multiple switching, the degree of ablation of the main vacuum contact and the auxiliary vacuum contact will be different, and the switching burden and electrical damage of the auxiliary vacuum contact will be more serious.

[0005] Therefore, it is necessary to provide a transition circuit which can reduce the switching task of the auxiliary vacuum contact and improve the electrical life of the on-load tap changer. Summary of the invention

[0006] The invention provides a vacuum on-load tap changer double-resistance transition circuit and a voltage regulation method to solve the problem of how to improve the electrical life of the vacuum on-load tap changer.

[0007] In order to solve the above problems, according to one aspect of the present invention, a vacuum on-load tap changer dual-resistance transition circuit is provided, the transition circuit comprising: a first main contact MC1, a second main contact MC2, a first auxiliary vacuum contact V1, a second auxiliary vacuum contact V3, a main vacuum contact V2, a first switch Z1, a second switch Z2, a first transition resistor R1 and a second transition resistor R2;

[0008] Among them, one end of the first main contact MC1 is connected to the odd-numbered tapping gear of the transformer voltage regulating winding; one end of the second main contact MC2 is connected to the even-numbered tapping gear of the transformer voltage regulating winding; one end of the first auxiliary vacuum contact V1 is respectively connected to the odd-numbered tapping gear of the transformer voltage regulating winding and the first switch Z1, and the other end is connected to one end of the first transition resistor R1; one end of the second auxiliary vacuum contact V3 is respectively connected to the even-numbered tapping gear of the transformer voltage regulating winding and the first switch Z1, and the other end is connected to one end of the second transition resistor R2; the other ends of the first transition resistor R1 and the second transition resistor R2 are both connected to the second switch Z2; one end of the main vacuum contact V2 is connected to the first switch Z1; the other ends of the main vacuum contact V2, the first main contact MC1 and the second main contact MC2 are all connected to the neutral point of the transformer for outputting load current;

[0009] When performing the task of cutting off the circulating current, the first auxiliary vacuum contact V1, the second auxiliary vacuum contact V3, the first transition resistor R1 and the second transition resistor R2 work in turn to reduce the switching task of the auxiliary vacuum contact, reduce the heating of the transition resistor and increase the electrical life of the on-load tap changer.

[0010] Preferably, when the first main contact MC1, the first auxiliary vacuum contact V1, the second auxiliary vacuum contact V3 and the main vacuum contact V2 are all in the on state, the first switch Z1 is connected to the odd-numbered tapping gear end of the transformer winding, the second switch Z2 is connected to the first transition resistor R1 end, the second main contact MC2 is in the off state, and the tap selector of the on-load tap changer is connected to the odd-numbered tapping gear of the transformer voltage regulating winding, the load current can be output through the first main contact MC1.

[0011] Preferably, when the second main contact MC2, the first auxiliary vacuum contact V1, the second auxiliary main vacuum contact V2 and the main second auxiliary vacuum contact V3 are all in the on state, the first switch Z1 is connected to the even-numbered tapping gear end of the transformer winding, the second switch Z2 is connected to the second transition resistor R2 end, the first main contact MC1 is in the off state, and the tap selector of the on-load tap changer is connected to the even-numbered tapping gear of the transformer voltage regulating winding, the load current can be output through the second main contact MC2.

[0012] Preferably, the method of switching the tap selector of the on-load tap changer from an odd-numbered tap position to an even-numbered tap position comprises:

[0013] The first main contact MC1 is disconnected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0014] The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted so that the main vacuum contact V2 is connected to the even-numbered tapping position end. During this process, the load current I N Flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence and outputs;

[0015] The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn for output;

[0016] The first auxiliary vacuum contact V1 is disconnected to generate an arc; after the arc in the first auxiliary vacuum contact V1 is completely extinguished, the second switch Z2 is adjusted to disconnect from the first transition resistor R1. During this process, the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0017] Close the first auxiliary vacuum contact V1, adjust the second switch Z2, so that the main vacuum contact V2 and the second transition resistor R2 are connected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0018] The second main contact MC2 is closed, so that the load current I N The voltage flows through the second main contact MC2 and is output, the tap change operation is completed, and the first-level voltage regulation is completed.

[0019] Preferably, the method of switching the tap selector of the on-load tap changer from an even-numbered tap position to an odd-numbered tap position comprises:

[0020] The second main contact MC2 is disconnected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0021] The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted to make the main vacuum contact V2 conductive with the odd-numbered tapping position end. During this process, the load current I N Flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence and outputs;

[0022] The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N It flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 for output;

[0023] The second auxiliary vacuum contact V3 is disconnected to generate an arc; after the arc in the second auxiliary vacuum contact V3 is completely extinguished, the second switch Z2 is adjusted to disconnect from the second transition resistor R2. During this process, the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0024] Close the second auxiliary vacuum contact V3, adjust the second switch Z2, so that the main vacuum contact V2 and the first transition resistor R1 are connected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0025] When the first main contact MC1 is closed, the load current I N The voltage flows through the first main contactor MC1 and is output, the tap change operation is completed, and the first-level voltage regulation is completed.

[0026] Preferably, the first switch Z1 is a mechanical single-contact switch or a conversion switch; the second switch Z2 is a mechanical single-contact switch or a conversion switch.

[0027] According to another aspect of the present invention, there is provided a method for voltage regulation using the vacuum on-load tap changer double resistance transition circuit as described above, the method comprising:

[0028] The first main contact MC1 is disconnected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0029] The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted to make the main vacuum contact V2 conductive with the even-numbered tapping position end. During this process, the load current IN Flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence and outputs;

[0030] The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0031] The first auxiliary vacuum contact V1 is disconnected to generate an arc; after the arc in the first auxiliary vacuum contact V1 is completely extinguished, the second switch Z2 is adjusted to disconnect from the first transition resistor R1. During this process, the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0032] Close the first auxiliary vacuum contact V1, adjust the second switch Z2, so that the main vacuum contact V2 and the second transition resistor R2 are connected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0033] The second main contact MC2 is closed, so that the load current I N The voltage flows through the second main contact MC2 and is output, and the tap change operation is completed, so that the tap selector of the on-load tap changer is switched from the odd-numbered tap position to the even-numbered tap position, completing the first-level voltage regulation.

[0034] According to another aspect of the present invention, there is provided a method for voltage regulation using the vacuum on-load tap changer double resistance transition circuit as described above, the method comprising:

[0035] The second main contact MC2 is disconnected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0036] The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted to make the main vacuum contact V2 conductive with the odd-numbered tapping position end. During this process, the load current I N Flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence and outputs;

[0037] The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N It flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 for output;

[0038] The second auxiliary vacuum contact V3 is disconnected to generate an arc. After the arc in the second auxiliary vacuum contact V3 is completely extinguished, the second switch Z2 is adjusted to disconnect from the second transition resistor R2. During this process, the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0039] Close the second auxiliary vacuum contact V3, adjust the second switch Z2, so that the main vacuum contact V2 and the first transition resistor R1 are connected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0040] When the first main contact MC1 is closed, the load current I N The voltage flows through the first main contact MC1 and the tap change operation is completed, and the tap selector of the on-load tap changer is switched from the even-numbered tap position to the odd-numbered tap position, completing the first-level voltage regulation.

[0041] The present invention provides a double-resistance transition circuit and a voltage regulation method for a vacuum on-load tap changer. Two auxiliary vacuum contact branches and one main vacuum contact branch are designed. The circulating current cutting task is performed by the two auxiliary vacuum contacts in turn. The switching procedure is symmetrical, so that the burning of the two auxiliary vacuum contacts is completely consistent, which reduces the switching task of the auxiliary vacuum contacts. Compared with the current transition circuit with a "single main vacuum contact and a single auxiliary vacuum contact" structure, the switching task of only one auxiliary vacuum contact is shared, and the switching capacity of the main vacuum contact and the auxiliary vacuum contact can be balanced. At the same time, two transition resistors are designed to work in rotation to solve the problem that the temperature of the transition resistor is too high due to the heating of the single transition resistor, resulting in the decomposition and gas production of transformer oil and the reduction of insulation performance, thereby improving the electrical life of the entire vacuum on-load tap changer. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0043] Figure 1 A circuit diagram of a double-resistance transition circuit 100 of a vacuum on-load tap changer according to an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0046] Figure 4A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0047] Figure 5 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0048] Figure 6 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0049] Figure 7 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0050] Figure 8 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0051] Fig. 9 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0052] Fig.10 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0053] Fig.11 A schematic diagram of a double-resistance transition circuit conversion of a vacuum on-load tap changer according to an embodiment of the present invention;

[0054] Fig.12 A schematic diagram of a conversion process of a double-resistance transition circuit of a vacuum on-load tap changer from an odd-numbered tap position to an even-numbered tap position according to an embodiment of the present invention;

[0055] Fig.13 A schematic diagram of a conversion process of a double-resistance transition circuit of a vacuum on-load tap changer from an even-numbered tapping position to an odd-numbered tapping position according to an embodiment of the present invention;

[0056] Fig.14 A circuit diagram of another vacuum on-load tap changer double resistance transition circuit according to an embodiment of the present invention;

[0057] Fig.15 It is a flow chart of a voltage regulation method 1500 for switching from an odd-numbered tapping position to an even-numbered tapping position using a double-resistance transition circuit of a vacuum on-load tap changer according to an embodiment of the present invention;

[0058] Fig.16 The flowchart is a voltage regulation method 1600 for switching from an even-numbered tap position to an odd-numbered tap position by using a double-resistance transition circuit of a vacuum on-load tap changer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0059] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0060] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0061] Figure 1 FIG. 1 is a circuit diagram of a vacuum on-load tap changer dual-resistance transition circuit 100 according to an embodiment of the present invention. Figure 1As shown, the double-resistance transition circuit and voltage regulation method of the vacuum on-load tap changer provided by the embodiment of the present invention are designed with two auxiliary vacuum contact branches and one main vacuum contact branch. The circulating current cutting task is performed by the two auxiliary vacuum contacts in turn. The switching procedure is symmetrical, so that the burning of the two auxiliary vacuum contacts is completely consistent, which reduces the switching task of the auxiliary vacuum contacts. Compared with the current transition circuit of "single main vacuum contact, single auxiliary vacuum contact" structure, it shares the switching task of only one auxiliary vacuum contact, and can balance the switching capacity of the main vacuum contact and the auxiliary vacuum contact; at the same time, the two transition resistors are designed to work in rotation to solve the problem that the temperature of the transition resistor is too high due to the heating of the single transition resistor, resulting in the decomposition and gas production of the transformer oil and the reduction of the insulation performance, thereby improving the electrical life of the entire vacuum on-load tap changer. A vacuum on-load tap changer dual-resistance transition circuit 100 provided in an embodiment of the present invention comprises: a first main contact MC1, a second main contact MC2, a first auxiliary vacuum contact V1, a second auxiliary vacuum contact V3, a main vacuum contact V2, a first switch Z1, a second switch Z2, a first transition resistor R1, and a second transition resistor R2; wherein, one end of the first main contact MC1 is connected to the odd-numbered tapping gear of the transformer voltage regulating winding; one end of the second main contact MC2 is connected to the even-numbered tapping gear of the transformer voltage regulating winding; one end of the first auxiliary vacuum contact V1 is respectively connected to the odd-numbered tapping gear of the transformer voltage regulating winding and the first switch Z1, and the other end is connected to one end of the first transition resistor R1; one end of the second auxiliary vacuum contact V3 is connected to the even-numbered tapping gear of the transformer voltage regulating winding. They are respectively connected to the even-numbered tapping gears of the transformer voltage regulating winding and the first switch Z1, and the other end is connected to one end of the second transition resistor R2; the other ends of the first transition resistor R1 and the second transition resistor R2 are both connected to the second switch Z2; one end of the main vacuum contact V2 is connected to the first switch Z1; the other ends of the main vacuum contact V2, the first main contact MC1 and the second main contact MC2 are all connected to the neutral point of the transformer for outputting load current; when performing the circulating current cutting task, the first auxiliary vacuum contact V1, the second auxiliary vacuum contact V3, the first transition resistor R1 and the second transition resistor R2 work in turn to reduce the switching task of the auxiliary vacuum contact, reduce the heating of the transition resistor, and improve the electrical life of the on-load tap changer.

[0062] Preferably, when the first main contact MC1, the first auxiliary vacuum contact V1, the second auxiliary vacuum contact V3 and the main vacuum contact V2 are all in the on state, the first switch Z1 is connected to the odd-numbered tapping gear end of the transformer winding, the second switch Z2 is connected to the first transition resistor R1 end, the second main contact MC2 is in the off state, and the tap selector of the on-load tap changer is connected to the odd-numbered tapping gear of the transformer voltage regulating winding, the load current can be output through the first main contact MC1.

[0063] Preferably, when the second main contact MC2, the first auxiliary vacuum contact V1, the second auxiliary main vacuum contact V2 and the main second auxiliary vacuum contact V3 are all in the on state, the first switch Z1 is connected to the even-numbered tapping gear end of the transformer winding, the second switch Z2 is connected to the second transition resistor R2 end, the first main contact MC1 is in the off state, and the tap selector of the on-load tap changer is connected to the even-numbered tapping gear of the transformer voltage regulating winding, the load current can be output through the second main contact MC2.

[0064] Preferably, the first switch Z1 is a mechanical single-contact switch or a conversion switch; the second switch Z2 is a mechanical single-contact switch or a conversion switch.

[0065] In the embodiment of the present invention, the first switch Z1 is a mechanical single-contact switch, including a first static contact 12, a second static contact 13 and a moving contact 11; the first static contact 12 is connected to the odd-numbered tapping gear; the second static contact 13 is connected to the even-numbered tapping gear; one end of the moving contact 11 is connected to the main vacuum contact V2, and the other end is slidably connected to the first static contact 12 and the second static contact 13. The second switch Z2 is a mechanical single-contact switch, including: a first static contact 22, a second static contact 23 and a moving contact 21; the first static contact 22 is connected to the first transition resistor R1; the second static contact 23 is connected to the second transition resistor R2; one end of the moving contact 21 is connected to the main vacuum contact V2, and the other end is slidably connected to the first static contact 23 and the second static contact 22.

[0066] In an embodiment of the present invention, when the tap selector of the on-load tap changer is connected to the odd-numbered tapping gear of the transformer voltage regulating winding, the first main contact MC1 is turned on, the second main contact MC2 is turned off, the first auxiliary vacuum contact V1 is turned on, the main vacuum contact V2 is turned on, and the second auxiliary vacuum contact V3 is turned on, the moving contact 11 of the first switch Z1 is connected to its first static contact 12, the moving contact 21 of the second switch Z2 is connected to its first static contact 22, and the load current is output through the first main contact MC1. When the tap selector of the on-load tap changer is connected to the even-numbered tapping position of the transformer regulating winding, the second main contact MC2 is turned on, the first main contact MC1 is turned off, the first auxiliary vacuum contact V1 is turned on, the main vacuum contact V2 is turned on, and the second auxiliary vacuum contact V3 is turned on. The moving contact 11 of the first switch Z1 is connected to its second static contact 13, the moving contact 21 of the second switch Z2 is connected to its second static contact 23, and the load current is output through the second main contact MC2.

[0067] Preferably, the method of switching the tap selector of the on-load tap changer from an odd-numbered tap position to an even-numbered tap position comprises:

[0068] The first main contact MC1 is disconnected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0069] The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted so that the main vacuum contact V2 is connected to the even-numbered tapping position end. During this process, the load current I N Flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence and outputs;

[0070] The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0071] The first auxiliary vacuum contact V1 is disconnected to generate an arc; after the arc in the first auxiliary vacuum contact V1 is completely extinguished, the second switch Z2 is adjusted to disconnect from the first transition resistor R1. During this process, the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0072] Close the first auxiliary vacuum contact V1, adjust the second switch Z2, so that the main vacuum contact V2 and the second transition resistor R2 are connected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0073] The second main contact MC2 is closed, so that the load current I N The voltage flows through the second main contact MC2 and is output, the tap change operation is completed, and the first-level voltage regulation is completed.

[0074] In the embodiment of the present invention, it is assumed that the initial position of the change-over selector of the tap selector of the on-load tap changer remains unchanged, and the gear number of the on-load tap changer is consistent with the contact group number of the tap selector, and the gear position of the on-load tap changer is to increase from an odd gear position N to an even gear position N+1.

[0075] When the tap selector is connected to the odd-numbered tap position of the transformer voltage regulating winding, Figure 2 As shown, the first main contact MC1 is turned on, the second main contact MC2 is turned off, the first auxiliary vacuum contact V1 is turned on, the main vacuum contact V2 is turned on, the second auxiliary vacuum contact V3 is turned on, the moving contact 11 of the first switch Z1 is connected to its first static contact 12, the moving contact 21 of the second switch Z2 is connected to its first static contact 22, and the load current is output through the first main contact MC1. When the tap selector is switched from an odd-numbered tapping position to an even-numbered tapping position, the specific operation method includes:

[0076] (1) Figure 2 As shown, the first main contact MC1 is closed and the load current I N Output through the first main contact MC1;

[0077] (2) Figure 3 As shown, the first main contact MC1 is disconnected, and the load current IN flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 in sequence to be output;

[0078] (3) Figure 4 As shown, the main vacuum contact V2 is disconnected to generate an arc; after the arc is extinguished, the load current I N The recovery voltage U across the main vacuum contact V2 flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence. V2 =I N ×R1;

[0079] (4) Figure 5 As shown, after the arc in the main vacuum contact V2 is completely extinguished, the moving contact 11 of the first switch Z1 is adjusted to rotate from connecting to the first static contact 12 to connecting to the second static contact 13. At this time, the load current I N Flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence and outputs;

[0080] (5) Figure 6 As shown, the main vacuum contact V2 is closed, the transition circuit is bridged, and a circulating current I is generated. c1 ; Load current I N The current I flowing through the main vacuum contact V2 is output from the even-numbered tap position end through the first switch Z1 and the main vacuum contact V2 in sequence; V2 =I N +I C1 ; Among them, I C1 =U S / R1, the U S is the on-load tapchanger level voltage;

[0081] (6) Figure 7 As shown, the first auxiliary vacuum contact V1 is disconnected to generate an arc; the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn for output; the recovery voltage across the first auxiliary vacuum contact V1 is U V1 =U S ;

[0082] (7) Figure 8As shown, after the arc in the first auxiliary vacuum contact V1 is completely extinguished, the moving contact 21 of the second switch Z2 is adjusted to be disconnected from its first static contact 22, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0083] (8) Fig. 9 As shown, the first auxiliary vacuum contact V1 is closed, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0084] (9) Fig.10 As shown, the movable contact 21 of the second switch Z2 is adjusted to be connected to the second static contact 23, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0085] (10) Fig.11 As shown, the second main contact MC2 is closed, and the load current I N The voltage flows through the second main contact MC2 and is output, the tap change operation is completed, and the switch completes the first-level voltage regulation.

[0086] When the tap selector switches from an odd-numbered tap position to an even-numbered tap position, the transition circuit conversion procedure is as follows: Fig.12 shown.

[0087] Preferably, the method of switching the tap selector of the on-load tap changer from an even-numbered tap position to an odd-numbered tap position comprises:

[0088] The second main contact MC2 is disconnected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0089] The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted to make the main vacuum contact V2 conductive with the odd-numbered tapping position end. During this process, the load current I N Flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence and outputs;

[0090] The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N It flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 for output;

[0091] The second auxiliary vacuum contact V3 is disconnected to generate an arc; after the arc in the second auxiliary vacuum contact V3 is completely extinguished, the second switch Z2 is adjusted to disconnect from the second transition resistor R2. During this process, the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0092] Close the second auxiliary vacuum contact V3, adjust the second switch Z2, so that the main vacuum contact V2 and the first transition resistor R1 are connected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0093] When the first main contact MC1 is closed, the load current I N The voltage flows through the first main contactor MC1 and is output, the tap change operation is completed, and the first-level voltage regulation is completed.

[0094] In the embodiment of the present invention, when the tap selector of the on-load tap changer is connected to the even-numbered taps of the transformer voltage regulating winding, Fig.11 As shown, the second main contact MC2 is turned on, the first main contact MC1 is turned off, the first auxiliary vacuum contact V1 is turned on, the main vacuum contact V2 is turned on, the second auxiliary vacuum contact V3 is turned on, the moving contact 11 of the first switch Z1 is connected to its second static contact 13, the moving contact 21 of the second switch Z2 is connected to its second static contact 23, and the load current is output through the second main contact MC2. When the tap selector is switched from an even-numbered tapping gear position to an odd-numbered tapping gear position, the specific operation method includes:

[0095] (1) The second main contact MC2 is disconnected, and the load current IN flows from the even-numbered tap position end through the first switch Z1 and the main vacuum contact V2 in sequence for output;

[0096] (2) The main vacuum contact V2 is disconnected to generate an arc. After the arc is extinguished, the load current I N The recovery voltage U across the main vacuum contact V2 flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence. V2 =I N ×R2;

[0097] (3) After the arc in the main vacuum contact V2 is completely extinguished, the moving contact of the first switch Z1 rotates from connecting to the second stationary contact 13 to connecting to the first stationary contact 12, and the load current I N Flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence and outputs;

[0098] (4) The main vacuum contact V2 is closed, the transition circuit is bridged, and a circulating current I is generated. C2 ; Load current IN The current I flowing through the main vacuum contact V2 flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2. V2 =I N -I C1 ; Among them, I C2 =U S / R2, the U S is the on-load tapchanger level voltage;

[0099] (5) The second auxiliary vacuum contact V3 is disconnected to generate an arc; the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; the recovery voltage across the second auxiliary vacuum contact V3 is U V3 =U S ;

[0100] (6) After the arc in the second auxiliary vacuum contact V3 is completely extinguished, the moving contact 21 of the second switch Z2 is adjusted to be disconnected from its second static contact 23, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0101] (7) The second auxiliary vacuum contact V3 is closed, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0102] (8) Adjust the movable contact 21 of the second switch Z2 to be rotationally connected to its first stationary contact 22, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn;

[0103] (9) Close the first main contact MC1, the load current I N The voltage flows through the first main contact MC1 and is output, the tap change operation is completed, and the switch completes the first-level voltage regulation.

[0104] When the tap selector switches from an even-numbered tap position to an odd-numbered tap position, the transition circuit conversion procedure is as follows: Fig.13 shown.

[0105] In the embodiment of the present invention, the switching tasks of the vacuum on-load tap changer transition circuit are shown in the following table:

[0106]

[0107] Among them, I N is the load current; Us is the on-load tap changer level voltage; R1 and R2 are transition resistors.

[0108] Fig.14FIG. 2 is a circuit diagram of another vacuum on-load tap changer double resistance transition circuit according to an embodiment of the present invention. Fig.14 As shown, only Figure 1 The first switch and the second switch in the embodiment are configured as transfer switches, and the other components are configured as Figure 1 The components are the same as in Figure 1 The functions and effects of the transition circuit shown are also the same and will not be described in detail here.

[0109] Fig.15 FIG. 1 is a flow chart of a voltage regulation method 1500 for converting an odd-numbered tapping position to an even-numbered tapping position using a double-resistance transition circuit of a vacuum on-load tap changer according to an embodiment of the present invention. Fig.15 As shown, a method 1500 for voltage regulation using the vacuum on-load tap changer double resistance transition circuit as described above is provided in an embodiment of the present invention, starting from step 1501, in step 1501, the first main contact MC1 is disconnected, and the load current IN flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 in sequence to be output.

[0110] In step 1502, the main vacuum contact V2 is disconnected to generate an arc. After the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted so that the main vacuum contact V2 is connected to the even-numbered tapping position end. In this process, the load current I N The voltage sequentially flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 for output.

[0111] In step 1503, the main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the even-numbered tap position end, the power flows sequentially through the first switch Z1 and the main vacuum contactor V2 for output.

[0112] In step 1504, the first auxiliary vacuum contact V1 is disconnected to generate an arc. After the arc in the first auxiliary vacuum contact V1 is completely extinguished, the second switch Z2 is adjusted to be disconnected from the first transition resistor R1. During this process, the load current I N From the even-numbered tap position end, the power flows sequentially through the first switch Z1 and the main vacuum contactor V2 for output.

[0113] In step 1505, the first auxiliary vacuum contact V1 is closed, and the second switch Z2 is adjusted so that the main vacuum contact V2 is connected to the second transition resistor R2, and the load current I N From the even-numbered tap position end, the power flows sequentially through the first switch Z1 and the main vacuum contactor V2 for output.

[0114] In step 1506, the second main contact MC2 is closed so that the load current I NThe voltage flows through the second main contact MC2 and is output, and the tap change operation is completed, so that the tap selector of the on-load tap changer is switched from the odd-numbered tap position to the even-numbered tap position, completing the first-level voltage regulation.

[0115] The voltage regulation method 1500 for switching from an odd-numbered tap position to an even-numbered tap position using a vacuum on-load tap changer dual-resistance transition circuit according to the embodiment of the present invention corresponds to the vacuum on-load tap changer dual-resistance transition circuit 100 according to another embodiment of the present invention, and will not be described in detail herein.

[0116] Fig.16 16 is a flow chart of a voltage regulation method 1600 for switching from an even-numbered tap position to an odd-numbered tap position using a double-resistance transition circuit of a vacuum on-load tap changer according to an embodiment of the present invention. Fig.16 As shown, the method 1600 for voltage regulation using the double resistance transition circuit of the vacuum on-load tap changer provided in the embodiment of the present invention starts from step 1601. In step 1601, the second main contact MC2 is disconnected, and the load current I N From the even-numbered tap position end, the power flows sequentially through the first switch Z1 and the main vacuum contactor V2 for output.

[0117] In step 1602, the main vacuum contact V2 is disconnected to generate an arc. After the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted so that the main vacuum contact V2 is connected to the odd-numbered tapping position end. In this process, the load current I N The voltage sequentially flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 for output.

[0118] In step 1603, the main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the odd-numbered tap position end, the voltage flows through the first switch Z1 and the main vacuum contactor V2 and is output.

[0119] In step 1604, the second auxiliary vacuum contact V3 is disconnected to generate an arc. After the arc in the second auxiliary vacuum contact V3 is completely extinguished, the second switch Z2 is adjusted to disconnect from the second transition resistor R2. During this process, the load current I N From the odd-numbered tap position end, the power flows sequentially through the first switch Z1 and the main vacuum contactor V2 for output.

[0120] In step 1605, the second auxiliary vacuum contact V3 is closed, and the second switch Z2 is adjusted so that the main vacuum contact V2 is connected to the first transition resistor R1, and the load current I N From the odd-numbered tap position end, the power flows sequentially through the first switch Z1 and the main vacuum contactor V2 for output.

[0121] In step 1606, the first main contact MC1 is closed, and the load current IN The voltage flows through the first main contact MC1 and the tap change operation is completed, and the tap selector of the on-load tap changer is switched from the even-numbered tap position to the odd-numbered tap position, completing the first-level voltage regulation.

[0122] The voltage regulation method 1600 for switching from an even-numbered tap position to an odd-numbered tap position using a vacuum on-load tap changer dual-resistance transition circuit according to an embodiment of the present invention corresponds to the vacuum on-load tap changer dual-resistance transition circuit 100 according to another embodiment of the present invention, and will not be described in detail herein.

[0123] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0124] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of the means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0125] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0126] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0127] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0128] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A vacuum on-load tap changer double resistance transition circuit, characterized in that: The transition circuit includes: a first main contact MC1, a second main contact MC2, a first auxiliary vacuum contact V1, a second auxiliary vacuum contact V3, a main vacuum contact V2, a first switch Z1, a second switch Z2, a first transition resistor R1 and a second transition resistor R2; Among them, one end of the first main contact MC1 is connected to the odd-numbered tapping gear of the transformer voltage regulating winding; one end of the second main contact MC2 is connected to the even-numbered tapping gear of the transformer voltage regulating winding; one end of the first auxiliary vacuum contact V1 is respectively connected to the odd-numbered tapping gear of the transformer voltage regulating winding and the first switch Z1, and the other end is connected to one end of the first transition resistor R1; one end of the second auxiliary vacuum contact V3 is respectively connected to the even-numbered tapping gear of the transformer voltage regulating winding and the first switch Z1, and the other end is connected to one end of the second transition resistor R2; the other ends of the first transition resistor R1 and the second transition resistor R2 are both connected to the second switch Z2; one end of the main vacuum contact V2 is connected to the first switch Z1; the other ends of the main vacuum contact V2, the first main contact MC1 and the second main contact MC2 are all connected to the neutral point of the transformer for outputting load current; When performing the task of cutting off the circulating current, the first auxiliary vacuum contact V1, the second auxiliary vacuum contact V3, the first transition resistor R1 and the second transition resistor R2 work in turn to reduce the switching task of the auxiliary vacuum contact, reduce the heating of the transition resistor and increase the electrical life of the on-load tap changer; The following method is used to realize the switching of the tap selector of the on-load tap changer from an odd-numbered tap position to an even-numbered tap position, including: The first main contact MC1 is disconnected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted so that the main vacuum contact V2 is connected to the even-numbered tapping position end. During this process, the load current I N Flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence and outputs; The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The first auxiliary vacuum contact V1 is disconnected to generate an arc; after the arc in the first auxiliary vacuum contact V1 is completely extinguished, the second switch Z2 is adjusted to disconnect from the first transition resistor R1. During this process, the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; Close the first auxiliary vacuum contact V1, adjust the second switch Z2, so that the main vacuum contact V2 and the second transition resistor R2 are connected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The second main contact MC2 is closed, so that the load current I N The current flows through the second main contact MC2 and is output, the tap change operation is completed, and the first-level voltage regulation is completed; Wherein, the first switch Z1 is a mechanical single-contact switch or a conversion switch.

2. The transition circuit according to claim 1, characterized in that: When the first main contact MC1, the first auxiliary vacuum contact V1, the second auxiliary vacuum contact V3 and the main vacuum contact V2 are all in the on state, the first switch Z1 is connected to the odd-numbered tapping gear end of the transformer winding, the second switch Z2 is connected to the first transition resistor R1 end, the second main contact MC2 is in the off state, and the tap selector of the on-load tap changer is connected to the odd-numbered tapping gear of the transformer voltage regulating winding, the load current can be output through the first main contact MC1.

3. The transition circuit according to claim 1, characterized in that: When the second main contact MC2, the first auxiliary vacuum contact V1, the second auxiliary main vacuum contact V2 and the main second auxiliary vacuum contact V3 are all in the on state, the first switch Z1 is connected to the even-numbered tapping gear end of the transformer winding, the second switch Z2 is connected to the second transition resistor R2 end, the first main contact MC1 is in the off state, and the tap selector of the on-load tap changer is connected to the even-numbered tapping gear of the transformer voltage regulating winding, the load current can be output through the second main contact MC2.

4. The transition circuit according to claim 1, characterized in that: The tap selector of the on-load tap changer is switched from an even-numbered tap position to an odd-numbered tap position by: The second main contact MC2 is disconnected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The main vacuum contact V2 is disconnected to generate an arc. After the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted to connect the main vacuum contact V2 to the odd-numbered tapping position end. During this process, the load current I N Flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence and outputs; The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N It flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 for output; The second auxiliary vacuum contact V3 is disconnected to generate an arc. After the arc in the second auxiliary vacuum contact V3 is completely extinguished, the second switch Z2 is adjusted to disconnect from the second transition resistor R2. During this process, the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; Close the second auxiliary vacuum contact V3, adjust the second switch Z2, so that the main vacuum contact V2 and the first transition resistor R1 are connected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; When the first main contact MC1 is closed, the load current I N The voltage flows through the first main contactor MC1 and is output, the tap change operation is completed, and the first-level voltage regulation is completed.

5. The transition circuit according to claim 1, characterized in that: The second switch Z2 is a mechanical single-contact switch or a conversion switch.

6. A method for voltage regulation using a vacuum on-load tap changer double resistance transition circuit as claimed in any one of claims 1 to 5, characterized in that: The method comprises: The first main contact MC1 is disconnected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The main vacuum contact V2 is disconnected to generate an arc; after the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted so that the main vacuum contact V2 is connected to the even-numbered tapping position end. During this process, the load current I N Flows through the first auxiliary vacuum contact V1, the first transition resistor R1 and the second switch Z2 in sequence and outputs; The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The first auxiliary vacuum contact V1 is disconnected to generate an arc; after the arc in the first auxiliary vacuum contact V1 is completely extinguished, the second switch Z2 is adjusted to disconnect from the first transition resistor R1. During this process, the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; Close the first auxiliary vacuum contact V1, adjust the second switch Z2, so that the main vacuum contact V2 and the second transition resistor R2 are connected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The second main contact MC2 is closed, so that the load current I N The voltage flows through the second main contact MC2 and is output, and the tap change operation is completed, so that the tap selector of the on-load tap changer is switched from the odd-numbered tap position to the even-numbered tap position, completing the first-level voltage regulation.

7. A method for voltage regulation using a vacuum on-load tap changer double resistor transition circuit as claimed in any one of claims 1 to 5, characterized in that: The method comprises: The second main contact MC2 is disconnected, and the load current I N From the even-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; The main vacuum contact V2 is disconnected to generate an arc. After the arc in the main vacuum contact V2 is completely extinguished, the first switch Z1 is adjusted to connect the main vacuum contact V2 to the odd-numbered tapping position end. During this process, the load current I N Flows through the second auxiliary vacuum contact V3, the second transition resistor R2 and the second switch Z2 in sequence and outputs; The main vacuum contact V2 is closed, the transition circuit is bridged, and the load current I N It flows from the odd-numbered tap position end through the first switch Z1 and the main vacuum contact V2 for output; The second auxiliary vacuum contact V3 is disconnected to generate an arc. After the arc in the second auxiliary vacuum contact V3 is completely extinguished, the second switch Z2 is adjusted to disconnect from the second transition resistor R2. During this process, the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; Close the second auxiliary vacuum contact V3, adjust the second switch Z2, so that the main vacuum contact V2 and the first transition resistor R1 are connected, and the load current I N From the odd-numbered tap position end, it flows through the first switch Z1 and the main vacuum contact V2 in turn; When the first main contact MC1 is closed, the load current I N The voltage flows through the first main contact MC1 and the tap change operation is completed, and the tap selector of the on-load tap changer is switched from the even-numbered tap position to the odd-numbered tap position, completing the first-level voltage regulation.

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