Voltage control system of on-load voltage regulating transformer

Abstract

The utility model discloses a voltage control system of an on-load voltage regulation transformer, which relates to the field of on-load voltage regulation control of transformers, and comprises a first microswitch, a second microswitch, a third microswitch and a fourth microswitch which are arranged in an on-load voltage regulation switch in a main transformer; a detection relay is arranged in the AC voltage detection module; the AC voltage detection module is used for detecting the voltage of the 10kV bus; a first normally open contact of the detection relay is respectively connected with a normally open contact of the upshift contactor, a second normally open contact of the detection relay and a first normally open contact of the auxiliary contactor; a second normally open contact of the auxiliary contactor is respectively connected with a second normally open contact of the detection relay and a first normally closed contact of the detection relay; the second normally-closed contact of the detection relay is connected with the first normally-closed contact of the detection relay and the coil of the auxiliary contactor. According to the invention, automatic control of the on-load tap changer is realized, and automatic voltage stabilization regulation of the bus voltage in a set range is completed.

Description

Technical Field

[0001] This application relates to the field of on-load tap-changing control technology for transformers, and in particular to a voltage control system for on-load tap-changing transformers. Background Technology

[0002] According to relevant regulations, the bus voltage fluctuation of a 10kV system must be controlled within ±7%. If the voltage fluctuation exceeds this range, it will affect the quality and safety of power supply to a certain extent.

[0003] Currently, if fluctuations in the bus voltage are detected in the system, and the on-load tap changer on the main transformer needs adjustment, the operators manually operate the tap changer to adjust the tap position to obtain a suitable voltage. However, the main drawback of this manual operation method is its low level of automation. Furthermore, if the operators are careless and fail to detect voltage over-limit issues in a timely manner, it will inevitably have a significant impact on the stability of the bus voltage. Summary of the Invention

[0004] The purpose of this application is to provide a voltage control system for an on-load tap-changing transformer, which realizes automatic control of the on-load tap changer and completes automatic voltage regulation of the bus voltage within a set range.

[0005] To achieve the above objectives, this application provides the following solution:

[0006] This application provides an on-load tap-changing transformer voltage control system, which includes at least: a main transformer, an AC voltage detection module, a circuit breaker, an up-slot contactor, a down-slot contactor, and an auxiliary contactor; the on-load tap-changing switch in the main transformer has a built-in first micro switch, a second micro switch, a third micro switch, and a fourth micro switch; the AC voltage detection module has a built-in detection relay;

[0007] The high-voltage side of the main transformer is connected to the 220kV busbar; the low-voltage side of the main transformer is connected to the 10kV busbar; the AC voltage detection module is used to detect the voltage of the 10kV busbar.

[0008] The normally open contacts of the circuit breaker are connected to the normally open contacts of the upshift contactor, the common terminal of the first micro switch, and the live wire, respectively; the first normally open contact of the detection relay is connected to the normally open contact of the upshift contactor, the second normally open contact of the detection relay, and the first normally open contact of the auxiliary contactor, respectively; the normally open contacts of the downshift contactor are connected to the second normally open contact of the detection relay and the second normally closed contact of the auxiliary contactor, respectively; the first normally closed contact of the auxiliary contactor is connected to the normally open contact of the upshift contactor and the normally open terminal of the first micro switch, respectively; the second normally open contact of the auxiliary contactor is connected to the second normally open contact of the detection relay and the first normally closed contact of the detection relay, respectively.

[0009] The common terminal of the second micro switch is connected to the common terminal of the first micro switch and the common terminal of the third micro switch, respectively; the normally open terminal of the second micro switch is connected to the normally open terminal of the third micro switch and the first normally closed contact of the detection relay, respectively; the common terminal of the fourth micro switch is connected to the common terminal of the third micro switch; the normally open terminal of the fourth micro switch is connected to the second normally closed contact of the auxiliary contactor and the coil of the downshift contactor, respectively; the second normally closed contact of the detection relay is connected to the first normally closed contact of the detection relay and the coil of the auxiliary contactor, respectively; the coil of the auxiliary contactor is connected to the coil of the downshift contactor; the coil of the upshift contactor is connected to the normally open terminal of the first micro switch, the coil of the auxiliary contactor, and the neutral wire, respectively.

[0010] Optionally, one end of the first normally closed contact of the auxiliary contactor is connected to one end of the first normally open contact of the auxiliary contactor; one end of the second normally open contact of the auxiliary contactor is connected to one end of the second normally closed contact of the auxiliary contactor; and the other end of the first normally open contact of the auxiliary contactor is connected to the other end of the second normally open contact of the auxiliary contactor.

[0011] Optionally, a minimum position limit switch is provided on the connection line between the first normally closed contact of the auxiliary contactor and the normally open terminal of the first micro switch.

[0012] The common terminal of the lowest gear limit switch is connected to the first normally closed contact of the auxiliary contactor; the normally closed terminal of the lowest gear limit switch is connected to the normally open terminal of the first micro switch.

[0013] Optionally, a maximum gear limit switch is provided on the connection line between the normally open terminal of the fourth micro switch and the second normally closed contact of the auxiliary contactor.

[0014] The common terminal of the highest gear limit switch is connected to the second normally closed contact of the auxiliary contactor; the normally closed terminal of the highest gear limit switch is connected to the normally open terminal of the fourth micro switch.

[0015] Optionally, the on-load tap-changing transformer voltage control system further includes: a first auxiliary relay and a second auxiliary relay;

[0016] The coil of the first auxiliary relay is connected to the coil of the upshift contactor and the normally closed contact of the second auxiliary relay, respectively; the normally closed contact of the second auxiliary relay is connected to the normally closed contact of the downshift contactor, respectively; the coil of the second auxiliary relay is connected to the coil of the downshift contactor and the normally closed contact of the first auxiliary relay, respectively; the normally closed contact of the first auxiliary relay is connected to the normally closed contact of the upshift contactor.

[0017] Optionally, the on-load tap-changing transformer voltage control system further includes: a manual up-shift / down-shift switch;

[0018] The first normally open terminal of the manual upshift / downshift switch is connected to the normally open terminal of the upshift contactor; the second normally open terminal and the common terminal of the manual upshift / downshift switch are respectively connected to the normally open contact of the downshift contactor.

[0019] Optionally, the manual upshift / downshift switch is a three-position selector switch.

[0020] Optionally, a first connecting plate is provided on the connection line between the first normally open contact of the detection relay and the normally open contact of the upshift contactor; a second connecting plate is provided on the connection line between the second normally open contact of the detection relay and the first normally open contact of the detection relay.

[0021] One end of the first connecting plate is connected to one end of the second connecting plate and the normally open contact of the shift contactor; the other end of the first connecting plate is connected to the first normally open contact of the detection relay; and the other end of the second connecting plate is connected to the second normally open contact of the detection relay.

[0022] Optionally, the AC voltage detection module is connected to the 10kV voltage transformer on the 10kV bus.

[0023] Optionally, the AC voltage detection module is model YVT8.

[0024] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0025] This application utilizes an AC voltage detection module to monitor the voltage of the 10kV bus in real time. Simultaneously, it effectively connects different auxiliary contacts of the detection relay within the AC voltage detection module to the up-shift contactor, down-shift contactor, auxiliary contactor, and different microswitches within the on-load tap changer. When the AC voltage detection module detects a rise / fall in the 10kV bus voltage, its internal detection relay activates, thereby effectively linking the various contacts and terminals to control the up / down circuit of the on-load tap changer, ultimately achieving automatic voltage regulation of the bus within a set range. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The main circuit diagram of the on-load tap-changing transformer voltage control system provided in the embodiments of this application;

[0028] Figure 2 The control loop diagram of the on-load tap-changing transformer voltage control system provided in the embodiments of this application is shown.

[0029] Symbol explanation:

[0030] Main transformer - TC, AC voltage detection module - VS, 10kV voltage transformer - PT1, 220kV voltage transformer - PT2, circuit breaker - Q1, upshift contactor - K1, downshift contactor - K2, auxiliary contactor - K20, first micro switch - S14, second micro switch - S13A, third micro switch - S13B, fourth micro switch - S12, detection relay - JC, lowest gear limit switch - S4, highest gear limit switch - S5, first auxiliary relay - K41, second auxiliary relay - K42, manual upshift / downshift switch - S3, first connecting pressure plate - 1LP, second connecting pressure plate - 2LP. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] The purpose of this application is to provide a voltage control system for an on-load tap-changing transformer, which realizes automatic control of the on-load tap changer and completes automatic voltage regulation of the bus voltage within a set range.

[0033] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] This embodiment provides an on-load tap-changing transformer voltage control system, which includes at least: a main transformer TC, an AC voltage detection module VS, a circuit breaker Q1, an up-slot contactor K1, a down-slot contactor K2, and an auxiliary contactor K20; the on-load tap-changing switch in the main transformer TC has a built-in first micro switch S14, a second micro switch S13A, a third micro switch S13B, and a fourth micro switch S12; the AC voltage detection module VS has a built-in detection relay JC.

[0035] like Figure 1 As shown, the high-voltage side of the main transformer TC is connected to the 220kV bus, and the low-voltage side of the main transformer TC is connected to the 10kV bus; the AC voltage detection module VS is connected to the 10kV voltage transformer PT1 on the 10kV bus, and the AC voltage detection module VS is used to detect the voltage of the 10kV bus.

[0036] In this embodiment, the AC voltage detection module VS is model YVT8.

[0037] like Figure 2 As shown, the normally open contacts (33-34) of circuit breaker Q1 are connected to the normally open contacts (53-54) of upshift contactor K1 and the common terminal C of the first micro switch S14, respectively; the first normally open contact JC11 of detection relay JC is connected to the normally open contact of upshift contactor K1, the second normally open contact JC21 of detection relay JC, and the first normally open contact (13-14) of auxiliary contactor K20, respectively; the normally open contacts (53-54) of downshift contactor K2 are connected to the second normally open contact JC21 of detection relay JC and the second normally closed contact (31-32) of auxiliary contactor K20, respectively; the auxiliary contact... The first normally closed contact (21-22) of contactor K20 is connected to the normally open contact of the upshift contactor K1 and the normally open terminal NO of the first micro switch S14, respectively; the second normally open contact (43-44) of auxiliary contactor K20 is connected to the second normally open contact JC21 and the first normally closed contact JC12 of detection relay JC, respectively; terminal 21 of auxiliary contactor K20 is connected to terminal 13 of auxiliary contactor K20; terminal 43 of auxiliary contactor K20 is connected to terminal 31 of auxiliary contactor K20; terminal 14 of auxiliary contactor K20 is connected to terminal 44 of auxiliary contactor K20.

[0038] The common terminal C of the second micro switch S13A is connected to the common terminal C of the first micro switch S14 and the common terminal C of the third micro switch S13B, respectively; the normally open terminal NO of the second micro switch S13A is connected to the normally open terminal NO of the third micro switch S13B and the first normally closed contact JC12 of the detection relay JC, respectively; the common terminal C of the fourth micro switch S12 is connected to the common terminal C of the third micro switch S13B; the normally open terminal NO of the fourth micro switch S12 is connected to the auxiliary contactor, respectively. The second normally closed contact of K20 is connected to the coil (A1-A2) of the downshift contactor K2; the second normally closed contact JC22 of the detection relay JC is connected to the first normally closed contact JC12 of the detection relay JC and the coil (A1-A2) of the auxiliary contactor K20; the coil of the auxiliary contactor K20 is connected to the coil of the downshift contactor K2; the coil (A1-A2) of the upshift contactor K1 is connected to the normally open terminal NO of the first micro switch S14, the coil of the auxiliary contactor K20, and the neutral wire N.

[0039] Furthermore, the above-mentioned on-load tap-changing transformer voltage control system also includes: a first auxiliary relay K41, a second auxiliary relay K42, and a manual upshift / downshift switch S3; the coils (A1-A2) of the first auxiliary relay K41 are respectively connected to the coil of the upshift contactor K1 and the normally closed contacts (31-32) of the second auxiliary relay K42; the normally closed contacts of the second auxiliary relay K42 are connected to the normally closed contacts (21-22) of the downshift contactor K2; the coil of the upshift contactor K1 is connected to the normally closed contacts of the downshift contactor K2; the coils (A1-A2) of the second auxiliary relay K42 are respectively connected to the coil of the downshift contactor K2 and the normally closed contacts (31-32) of the first auxiliary relay K41; the normally closed contacts of the first auxiliary relay K41 are connected to the normally closed contacts (21-22) of the upshift contactor K1; the coil of the downshift contactor is connected to the normally closed contacts of the upshift contactor K1. The first normally open terminal 1 of the manual upshift / downshift switch S3 is connected to the normally open terminal of the upshift contactor K1; the second normally open terminal 3 and the common terminals 2-4 of the manual upshift / downshift switch S3 are respectively connected to the normally open contacts of the downshift contactor K2.

[0040] In this embodiment, the manual upshift / downshift switch S3 is a three-position selector switch. After being switched to one of the two positions and released, it automatically returns to the middle position. When switched to the "upshift" position, terminals 1-2 are connected and terminals 3-4 are disconnected; when switched to the "downshift" position, terminals 1-2 are disconnected and terminals 3-4 are connected.

[0041] In a preferred embodiment, a minimum gear limit switch S4 is provided on the connection line between the first normally closed contact of the auxiliary contactor K20 and the normally open terminal NO of the first micro switch S14; a maximum gear limit switch S5 is provided on the connection line between the normally open terminal NO of the fourth micro switch S12 and the second normally closed contact of the auxiliary contactor K20. Specifically, the common terminal C of the minimum gear limit switch S4 is connected to the first normally closed contact of the auxiliary contactor K20; the normally closed terminal NC of the minimum gear limit switch S4 is connected to the normally open terminal NO of the first micro switch S14; the common terminal C of the maximum gear limit switch S15 is connected to the second normally closed contact of the auxiliary contactor K20; and the normally closed terminal NC of the maximum gear limit switch S15 is connected to the normally open terminal NO of the fourth micro switch S12.

[0042] In another preferred embodiment, a first connecting plate 1LP is provided on the connection line between the first normally open contact JC11 of the detection relay JC and the normally open contact of the upshift contactor K1; a second connecting plate 2LP is provided on the connection line between the second normally open contact JC21 of the detection relay JC and the first normally open contact JC11 of the detection relay JC; one end 1 of the first connecting plate 1LP is connected to one end 1 of the second connecting plate 2LP and the normally open contact of the upshift contactor K1; the other end 2 of the first connecting plate 1LP is connected to the first normally open contact JC11 of the detection relay JC; and the other end 2 of the second connecting plate 2LP is connected to the second normally open contact JC21 of the detection relay JC.

[0043] To verify the effectiveness of the above-mentioned on-load tap-changing transformer voltage control system, its working principle is explained in detail below:

[0044] (1) During automatic upshifting:

[0045] When VS detects that the 10kV bus voltage has dropped to 9.3kV, the corresponding JC will activate. Terminals 11-14 of JC11 will change from open to closed, and terminals 21-24 of JC12 will change from closed to open. At this time, the coil of K1 will be energized, and terminals 53-54 of K1 will close. The on-load tap changer will start to rotate and increase its speed.

[0046] When the on-load tap changer is rotated to the position, S14 inside the on-load tap changer is activated. The C-NO terminal of S14 changes from open to closed, and it is connected in parallel with the 53-54 terminals of K1 and the 11-14 terminals of JC11 to supply power to the coil of K1.

[0047] When the on-load tap changer continues to rotate to the position, S13A starts, and the C-NO terminal of S13A changes from open to closed. Because the 21-24 terminals of JC12 are open at this time, the coil of K20 cannot be energized. Although the C-NO terminal of S13A changes from open to closed, this has no substantial impact on the circuit.

[0048] At this point, the on-load tap changer continues to rotate until the winding turns switching is complete. Two scenarios can occur: First, if the bus voltage rises above 9.3kV after the switching, the JC (Jack Cover) releases, and the on-load tap changer stops increasing its range. Second, if the bus voltage fails to rise above 9.3kV after the switching, the JC will not release, and the on-load tap changer will continue increasing its range. The following provides a detailed explanation of these two scenarios:

[0049] When the bus voltage rises above 9.3kV, VS immediately samples and detects that the 10kV bus voltage has risen to 9.3kV. At this time, JC is immediately released, and terminals 11-14 of JC11 will change from closed to open, and terminals 21-24 of JC12 will change from open to closed. Since the C-NO terminal of S13A is closed at this time, the coil of K20 will be connected at the moment when terminals 21-24 of JC12 are closed.

[0050] At the instant the coil of K20 is energized, terminals 21-22 of K20 change from closed to open, terminals 13-14 of K20 change from open to closed, terminals 43-44 of K20 change from open to closed, and terminals 31-32 of K20 change from closed to open.

[0051] As the on-load tap changer continues to rotate, after reaching the S13A release position, the C-NO terminal of S13A changes from closed to open;

[0052] The on-load tap changer continues to rotate. When it reaches the S14 release position, the C-NO terminal of S14 changes from closed to open. At this time, the coil of K1 is de-energized, and the 53-54 terminals of K1 change from closed to open. At this time, the coil of K20 is de-energized, and the 21-22 terminals of K20 change from open to closed, the 13-14 terminals of K20 change from closed to open, the 43-44 terminals of K20 change from closed to open, and the 31-32 terminals of K20 change from open to closed. At this time, the circuit returns to its initial state.

[0053] When the coil of K1 is de-energized, the rotational power of the on-load tap changer disappears, but it will continue to rotate due to inertia until it stops. At this time, the on-load tap changer has rotated a full revolution and the gear has been upgraded by 1 level.

[0054] When the bus voltage does not rise above 9.3kV, JC will not release and will continue to perform the upshift operation. Terminals 11-14 of JC11 will remain closed, and terminals 21-24 of JC12 will remain open. At this time, the on-load tap changer will not stop and will continue to rotate to perform the next shift operation until the 10kV bus voltage is adjusted to the specified range. At the same time, after the VS detection is normal, JC will release, and the on-load tap changer will stop operating.

[0055] (2) During automatic downshifting:

[0056] When VS detects that the 10kV bus voltage rises to 10.7kV, its corresponding JC operates. Terminals 11-14 of JC21 change from open to closed, and terminals 21-24 of JC22 change from closed to open. At this time, the coil of K2 is energized, terminals 53-54 of K2 close, and the on-load tap changer rotates to downshift.

[0057] When the on-load tap changer is turned to the position, S12 starts, and the C-NO terminal of S12 changes from open to closed. It is connected in parallel with the 53-54 terminals of K2 and the 11-14 terminals of JC21 to supply power to the coil of K2.

[0058] When the on-load tap changer continues to rotate to the position, S13B starts, and the C-NO terminal of S13B changes from open to closed. Because the 21-24 terminals of JC22 are in the open state at this time, the coil of K20 cannot be energized. Although the C-NO terminal of S13B changes from open to closed, it has no substantial impact on the circuit.

[0059] At this point, the on-load tap changer continues to rotate until the winding turns have been switched. Two scenarios can occur: First, after the switch is complete, the bus voltage drops below 10.7kV. In this case, the JC releases, and the on-load tap changer stops downsizing. Second, after the switch is complete, the bus voltage fails to drop below 10.7kV. In this case, the JC will not release, and the on-load tap changer continues downsizing. The following provides a detailed explanation of these two scenarios:

[0060] When the bus voltage drops below 10.7kV, VS immediately samples and detects that the 10kV bus voltage rises to 10.7kV. At this time, JC is immediately released, and terminals 11-14 of JC21 will change from closed to open, while terminals 21-24 of JC22 will change from open to closed. Since terminals C-NO of S13B are closed at this time, the coil of K20 is connected at the instant terminals 21-24 of JC22 are closed.

[0061] At the instant the coil of K20 is energized, terminals 21-22 of K20 change from closed to open, terminals 13-14 of K20 change from open to closed, terminals 43-44 of K20 change from open to closed, and terminals 31-32 of K20 change from closed to open.

[0062] As the on-load tap changer continues to rotate, after reaching the S13B release position, the C-NO terminal of S13B changes from closed to open.

[0063] The on-load tap changer continues to rotate. When it reaches the release position of S12, the C-NO terminal of S12 changes from closed to open. At this time, the coil of K2 is de-energized, and the 53-54 terminals of K2 change from closed to open. At this time, the coil of K20 is de-energized, and the 21-22 terminals of K20 change from open to closed, the 13-14 terminals of K20 change from closed to open, the 43-44 terminals of K20 change from closed to open, and the 31-32 terminals of K20 change from open to closed.

[0064] When the coil of K2 is de-energized, the rotational power of the on-load tap changer disappears, but it will continue to rotate due to inertia until it stops. At this time, the on-load tap changer has rotated a full revolution and the gear has been downgraded by 1 level.

[0065] When the bus voltage does not drop below 10.7kV, JC will not release and will continue to perform the downshifting operation. Terminals 11-14 of JC21 will remain closed, and terminals 21-24 of JC22 will remain open. At this time, the on-load tap changer will not stop and will continue to rotate to perform the next tap change operation until the 10kV bus voltage is adjusted to the specified range. At the same time, after the VS detection is normal, JC will release, and the on-load tap changer will stop operating.

[0066] The above process details the automatic upshifting and downshifting process of the on-load tap-changing transformer voltage control system. However, the on-load tap-changing transformer voltage control system is also equipped with a manual upshifting and downshifting switch. Manual upshifting and downshifting can also be achieved by rotating this switch. Its working principle is similar to that of the automatic upshifting and downshifting described above, so it will not be explained again.

[0067] In addition, the function of individual components is further explained below:

[0068] The on-load tap changer has 17 maximum positions and 1 minimum position. S4 is the minimum position limit switch. When S4's C-NC terminal opens, the upshift contactor K1 is de-energized. This prevents the on-load tap changer from exceeding its limit position due to improper operation after it has already been downshifted to position 1, thus preventing damage to the switch. The minimum position limit switch S5 operates on the same principle as S4.

[0069] The 21-22 terminals of K2 are connected in series with the coil of K1, and the 21-22 terminals of K1 are connected in series with the coil of K2. The purpose is to prevent the on-load tap changer from both shifting up and down at the same time, so as to avoid damaging the switch power mechanism.

[0070] The coil of K41 is connected in parallel with the coil of K1. Its purpose is to be used as an auxiliary relay to expand the auxiliary contacts. Since the coil of K1 only has two open and two closed auxiliary contacts, in order to prevent the number of auxiliary contacts from being insufficient, the coil of K41 is added in parallel with the coil of K1. When the auxiliary contacts of K1 are insufficient, the auxiliary contacts of K41 can be used directly. The same applies to K42.

[0071] In summary, this application has the following main advantages:

[0072] (1) Improve voltage stability. The AC voltage detection module can monitor voltage changes in real time and adjust the transformer taps in a timely manner to ensure that the voltage is stable within the set range and reduce fluctuations.

[0073] (2) Improve power supply quality. Automatic control can respond quickly to load changes, reduce voltage fluctuations and flicker, improve power quality, and reduce interference to sensitive equipment.

[0074] (3) Reduced human intervention. Automated control reduces reliance on manual operation, lowers the risk of human error, and reduces the workload of maintenance personnel.

[0075] (4) Improve system efficiency. The automatic control system can optimize the transformer operating status in a timely manner according to the changes in grid-side voltage, reduce unnecessary energy loss, and improve the overall system efficiency.

[0076] (5) Adapting to complex power grids. In complex power grids with distributed generation and renewable energy integration, automatic control can better cope with voltage fluctuations and ensure stable grid operation.

[0077] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0078] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A voltage control system for an on-load tap-changing transformer, characterized in that, The on-load tap-changing transformer voltage control system includes at least: a main transformer, an AC voltage detection module, a circuit breaker, an up-slot contactor, a down-slot contactor, and an auxiliary contactor; the on-load tap-changing switch in the main transformer has a built-in first micro switch, a second micro switch, a third micro switch, and a fourth micro switch; the AC voltage detection module has a built-in detection relay; The high-voltage side of the main transformer is connected to the 220kV busbar; the low-voltage side of the main transformer is connected to the 10kV busbar; the AC voltage detection module is used to detect the voltage of the 10kV busbar. The normally open contacts of the circuit breaker are connected to the normally open contacts of the upshift contactor, the common terminal of the first micro switch, and the live wire, respectively; the first normally open contact of the detection relay is connected to the normally open contact of the upshift contactor, the second normally open contact of the detection relay, and the first normally open contact of the auxiliary contactor, respectively; the normally open contacts of the downshift contactor are connected to the second normally open contact of the detection relay and the second normally closed contact of the auxiliary contactor, respectively; the first normally closed contact of the auxiliary contactor is connected to the normally open contact of the upshift contactor and the normally open terminal of the first micro switch, respectively; the second normally open contact of the auxiliary contactor is connected to the second normally open contact of the detection relay and the first normally closed contact of the detection relay, respectively. The common terminal of the second micro switch is connected to the common terminal of the first micro switch and the common terminal of the third micro switch, respectively; the normally open terminal of the second micro switch is connected to the normally open terminal of the third micro switch and the first normally closed contact of the detection relay, respectively; the common terminal of the fourth micro switch is connected to the common terminal of the third micro switch; the normally open terminal of the fourth micro switch is connected to the second normally closed contact of the auxiliary contactor and the coil of the downshift contactor, respectively; the second normally closed contact of the detection relay is connected to the first normally closed contact of the detection relay and the coil of the auxiliary contactor, respectively; the coil of the auxiliary contactor is connected to the coil of the downshift contactor; the coil of the upshift contactor is connected to the normally open terminal of the first micro switch, the coil of the auxiliary contactor, and the neutral wire, respectively.

2. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, One end of the first normally closed contact of the auxiliary contactor is connected to one end of the first normally open contact of the auxiliary contactor; one end of the second normally open contact of the auxiliary contactor is connected to one end of the second normally closed contact of the auxiliary contactor; and the other end of the first normally open contact of the auxiliary contactor is connected to the other end of the second normally open contact of the auxiliary contactor.

3. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, A minimum position limit switch is provided on the connection line between the first normally closed contact of the auxiliary contactor and the normally open terminal of the first micro switch. The common terminal of the lowest gear limit switch is connected to the first normally closed contact of the auxiliary contactor; the normally closed terminal of the lowest gear limit switch is connected to the normally open terminal of the first micro switch.

4. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, A maximum gear limit switch is provided on the connection line between the normally open terminal of the fourth micro switch and the second normally closed contact of the auxiliary contactor. The common terminal of the highest gear limit switch is connected to the second normally closed contact of the auxiliary contactor; the normally closed terminal of the highest gear limit switch is connected to the normally open terminal of the fourth micro switch.

5. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, The on-load tap-changing transformer voltage control system further includes: a first auxiliary relay and a second auxiliary relay; The coil of the first auxiliary relay is connected to the coil of the upshift contactor and the normally closed contact of the second auxiliary relay, respectively; the normally closed contact of the second auxiliary relay is connected to the normally closed contact of the downshift contactor, respectively; the coil of the second auxiliary relay is connected to the coil of the downshift contactor and the normally closed contact of the first auxiliary relay, respectively; the normally closed contact of the first auxiliary relay is connected to the normally closed contact of the upshift contactor.

6. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, The on-load tap-changing transformer voltage control system also includes: a manual up-shift and down-shift switch; The first normally open terminal of the manual upshift / downshift switch is connected to the normally open terminal of the upshift contactor; the second normally open terminal and the common terminal of the manual upshift / downshift switch are respectively connected to the normally open contact of the downshift contactor.

7. The on-load tap-changing transformer voltage control system according to claim 6, characterized in that, The manual upshift / downshift switch is a three-position selector switch.

8. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, A first connecting plate is provided on the connection line between the first normally open contact of the detection relay and the normally open contact of the upshift contactor; a second connecting plate is provided on the connection line between the second normally open contact of the detection relay and the first normally open contact of the detection relay. One end of the first connecting plate is connected to one end of the second connecting plate and the normally open contact of the shift contactor; the other end of the first connecting plate is connected to the first normally open contact of the detection relay; and the other end of the second connecting plate is connected to the second normally open contact of the detection relay.

9. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, The AC voltage detection module is connected to the 10kV voltage transformer on the 10kV bus.

10. The on-load tap-changing transformer voltage control system according to claim 1, characterized in that, The AC voltage detection module is model YVT8.

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