Vacuum load variable voltage regulating device

Abstract

The application discloses a kind of vacuum load variable voltage regulating devices, including with transformer oil cavity communication oil pressure driving device, by oil pressure driving device for adjusting transformer secondary coil turns voltage regulating device, for realizing voltage regulating on-load switching electronic switching device and controller, the oil pressure driving device and electronic switching device are controlled to controller;The voltage regulating device includes several voltage regulating sub-device, the electronic switching device includes the same electronic switching sub-device as the number of voltage regulating sub-device, several voltage regulating sub-device and corresponding electronic switching sub-device are built with load voltage regulating mechanism;Scheme by design oil pressure driving device executes segmented, mechanical type wide-range accurate voltage regulating action, matches electronic switching device to carry out on-load switching, expands voltage regulating range, while significantly improves the stability and security when voltage regulating.

Description

Technical Field

[0001] This invention relates to the field of transformer voltage regulation technology, specifically to a vacuum on-load variable voltage regulation device. Background Technology

[0002] Residential users' electricity voltage should be stable between 198V and 235.4V. However, due to the numerous factors causing voltage anomalies in the power distribution sector, the rectification work is arduous and requires significant investment, resulting in residential users' voltage often failing to meet the normal voltage requirements of the national standard. The main reasons for substandard voltage in residential users' power distribution sector are as follows: a) The transmission lines in the distribution area are too long, resulting in excessive voltage drop and low voltage at the end of the line; b) The distribution area lacks reactive power compensation devices or the capacity of the reactive power compensation devices is insufficient; c) The transmission lines in the distribution area are old and cannot meet the increased load of the area; d) Abnormal output voltage of the distribution transformer, etc.

[0003] The current solutions for substandard output voltage of distribution transformers caused by the above reasons are not perfect and mainly include the following: a) installing a 10kV line series compensation device; b) installing a 10kV line voltage stabilizer; c) adjusting the substation bus voltage; d) adjusting the distribution transformer tap changer, etc.

[0004] As can be seen from the above-mentioned governance methods, the main measure for controlling the output voltage of distribution transformers is still to regulate the voltage from higher-level transmission lines or substations to achieve the goal of normal input voltage on the high-voltage side of the distribution transformer. However, due to the higher procurement cost, lower regulation accuracy, and poorer self-regulation capability of higher voltage level equipment, voltage control in the distribution field with lower voltage levels is a more economical, reliable, and accurate approach, and it is also a direction that needs to be addressed in the future. Currently, main grid transformers have gradually adopted on-load tap changer technology, but the distribution network still uses the outdated off-load tap changer technology. This technology has a small voltage regulation range, only ±5%, and the risk factor is high and the work efficiency is low when maintenance personnel adjust the voltage during power outages. It cannot meet the voltage regulation needs of distribution transformers, making the output voltage of the transformer still uncontrollable.

[0005] Chinese Patent, Publication No. CN106920656B, Publication Date: February 19, 2019, relates to an autotransformer with a high-voltage on-load tap-changing coil and a low-voltage off-load tap-changing coil. The first winding of each phase of the autotransformer is connected at both ends and then connected to the first or second end of the on-load tap-changing coil via a switch. The second end of the on-load tap-changing coil serves as the negative terminal of that phase, and the first end serves as the positive terminal. The first end of the second winding is connected to the on-load tap-changing coil as a sliding contact. While this solution can achieve a wide range of voltage regulation for both high and low voltage, the process involves gradually switching to all stages of the on-load or off-load tap-changing coil by traversing the circuit with a sliding contact, sequentially determining whether the voltage regulation meets the requirements. This process is too slow and lacks specificity. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of small pressure regulation range and low pressure regulation accuracy faced by traditional pressure regulation technology. A vacuum on-load variable pressure regulation device is designed. By designing a hydraulic drive device to perform segmented, mechanical, large-range, and precise pressure regulation actions, and matching an electronic switching device for on-load switching, the pressure regulation range is expanded while significantly improving the stability and safety of pressure regulation.

[0007] One technical solution provided in this embodiment of the invention is a vacuum on-load variable voltage regulating device, comprising a hydraulic drive device connected to the transformer oil chamber, a voltage regulating device driven by the hydraulic drive device for adjusting the number of turns of the transformer secondary coil, an electronic switching device for realizing on-load voltage regulation switching, and a controller. The hydraulic drive device and the electronic switching device are controlled by the controller. The voltage regulating device includes a plurality of voltage regulating sub-devices, and the electronic switching device includes the same number of electronic switching sub-devices as the voltage regulating sub-devices. The plurality of voltage regulating sub-devices and the corresponding electronic switching sub-devices constitute an on-load voltage regulating mechanism.

[0008] In this scheme, the hydraulic drive unit uses transformer oil as the power medium to cool the transformer oil while simultaneously filtering and cleaning it, thus improving the safety and lifespan of the transformer. Since the voltage regulating sub-units correspond to precise voltage adjustment within a specific range, several sub-units implement segmented voltage regulation. Driving the corresponding sub-units with the hydraulic drive unit allows for coarse-to-fine voltage adjustment. During mechanical voltage regulation, to ensure stable output on the transformer secondary side, the corresponding electronic switching sub-unit remains inactive. After the mechanical voltage regulation process is complete, the transformer secondary side needs to switch to the corresponding voltage value. Therefore, the electronic switching sub-unit must operate according to the set logic to ensure rapid, safe, and reliable switching. Thus, this scheme significantly improves the stability and safety of voltage regulation while expanding the voltage regulation range.

[0009] Preferably, the hydraulic drive device includes an oil guide pipe, a return pipe, a filter chamber, a first oil chamber, a second oil chamber, a first oil pump, a second oil pump, a first oil delivery pipe, a second oil delivery pipe, and a bidirectional oil valve mechanism matching the voltage regulating device. The oil guide pipe connects the transformer oil chamber and the filter chamber. The first oil chamber and the second oil chamber are respectively connected to the filter chamber. The first oil pump is used to inject the transformer oil in the first oil chamber into the voltage regulating chamber of the voltage regulating device. The return pipe connects the voltage regulating chamber and the transformer oil chamber. Both the first oil delivery pipe and the second oil delivery pipe are provided with bidirectional oil valve mechanisms. The second oil pump is connected to the first oil delivery pipe and the second oil delivery pipe respectively through a two-way oil valve to inject the transformer oil into the drive chamber of the voltage regulating device.

[0010] In this scheme, the filter chamber can filter the transformer oil, making the transformer oil injected into the voltage regulating chamber cleaner, and improving the arc extinguishing effect at the moment of voltage switching; at the same time, the filtered unclean transformer oil can be injected into the drive chamber as the driving power medium, effectively improving the utilization efficiency of waste oil; both the first oil supply pipe and the second oil supply pipe are equipped with a two-way oil valve mechanism, which can ensure that the driving direction in each drive chamber is variable and adjustable.

[0011] Preferably, the system also includes a refueling tank, an oil injection pipe, an oil level sensor, and a valve. The oil injection pipe connects the refueling tank and the first oil chamber for replenishing and cleaning transformer oil. The valve and the oil level sensor are electrically connected to the controller. The oil level sensor is installed inside the transformer to detect the transformer oil level. When the oil level is lower than a certain set value, the controller opens the valve to inject the transformer oil from the refueling tank into the first oil chamber. The transformer oil in the first oil chamber is then injected into the transformer by a first oil pump to replenish the transformer oil.

[0012] Preferably, the voltage regulating device includes a load plate and a first voltage regulating device, a second voltage regulating device, a third voltage regulating device, and a fourth voltage regulating device disposed on the load plate. The load plate is connected to the secondary coil of the transformer to achieve stepless voltage regulation within a rated voltage range of ±20% according to the load ratio of the load plate.

[0013] In this scheme, the first voltage regulating device, the second voltage regulating device, the third voltage regulating device, and the fourth voltage regulating device work together with the load plate to achieve segmented voltage regulation function. This segmented voltage regulation process involves the initial judgment (determining which segment the voltage value to be regulated belongs to) and the subsequent fine adjustment (the specific voltage value), which can significantly improve the efficiency of voltage regulation, and the voltage regulation range can be expanded through segmented voltage regulation.

[0014] Preferably, the first, second, third, and fourth voltage regulating devices have the same structure. The first voltage regulating device includes a first voltage regulating cavity, a first driving cavity, a first moving block disposed in the first driving cavity, and a conductive head fixedly connected to the first moving block. The contact of the conductive head abuts against the load plate. When the first moving block moves in the first driving cavity, it synchronously drives the conductive head to move on the load plate to achieve stepless voltage regulation.

[0015] In this scheme, when voltage regulation is required, the controller first determines which voltage regulation segment the voltage regulation value falls into. After determining the voltage regulation segment, it starts to drive the drive chamber of the voltage regulation sub-device. Specifically, by injecting transformer oil, a force is applied to the first drive block located in the first drive chamber, driving the first drive block to move a certain distance in a certain direction. The moving distance can be precisely controlled according to the amount of transformer oil injected, thereby achieving precise adjustment. Subsequently, the conductive head moves in the first voltage regulation chamber, and the contact of the conductive head moves a certain distance on the load plate, thus achieving precise voltage regulation.

[0016] Preferably, the first, second, third, and fourth pressure regulating devices are all equipped with a bidirectional oil valve mechanism. The bidirectional oil valve mechanism includes a first bidirectional oil valve and a second bidirectional oil valve. The first and second bidirectional oil valves are respectively connected to the first oil supply pipe and the second oil supply pipe. The first and second bidirectional oil valves are simultaneously closed or opened to drive the movement of the corresponding moving blocks in the first, second, third, or fourth pressure regulating devices to achieve pressure regulation.

[0017] In this scheme, since the injected transformer oil is needed to provide thrust to the drive block in the drive cavity, a flow channel needs to be formed at both ends of the drive cavity. Therefore, a first bidirectional oil valve and a second bidirectional oil valve are configured on the external oil supply pipe of each drive cavity, that is, one end injects transformer oil and the other end discharges transformer oil, so as to ensure that the drive block can perform phase-fixed movement according to the direction of transformer oil injection.

[0018] Preferably, the load ratio formula for the load plate is as follows:

[0019]

[0020] λ is the load ratio, U max The maximum adjustable voltage of the secondary coil, U min L is the minimum adjustable voltage of the secondary coil, and L is the effective length of the load plate.

[0021] In this scheme, the voltage of the transformer is proportional to the turns ratio. Therefore, the number of turns of the adjustable coil is designed according to the adjustable range of the transformer. Then, the adjustable coil is used as the adjustable unit and a mapping is established with the load plate. That is, the number of turns corresponding to a unit stroke can be obtained through the conversion relationship, and the range of adjustable voltage corresponding to a unit stroke can be obtained. Therefore, the adjustable voltage value per unit stroke is characterized by the load ratio, thereby realizing the conversion from stepped voltage regulation to stepless voltage regulation, or in other words, realizing the upgrade from coarse adjustment to fine adjustment.

[0022] Preferably, the electronic switching sub-device includes a first disconnect switch, a second disconnect switch, and an on-load switching sub-mechanism. The first disconnect switch is disposed on the first output line, and the second disconnect switch is disposed on the second output line. Both the first and second output lines are connected to a common bus. The on-load switching sub-mechanism is electrically connected between the first and second output lines to achieve on-load switching.

[0023] In this scheme, the voltage adjustment range between the first output line and the second output line is the voltage adjustment range of the first voltage regulating sub-device. The mechanical voltage adjustment of the first voltage regulating sub-device has been described above and will not be repeated here. After the mechanical voltage adjustment process is completed, the voltage output needs to be switched from the first output line to the second output line through the on-load switching sub-mechanism. The controller makes precise adjustments according to the set logic.

[0024] Preferably, the on-load switching submechanism includes a first relay, a second relay, and a first current limiter. The first terminal of the first relay is electrically connected to the first output line, the first terminal of the second relay is electrically connected to the second output line, the second terminals of the first relay and the second terminal of the second relay are both electrically connected to the first terminal of the first current limiter, and the second terminal of the first current limiter is electrically connected to the common bus.

[0025] In this scheme, precise switching can be achieved through the connection structure of the components of the on-load switching submechanism and the control logic of the controller. For example, when it is necessary to switch the voltage output from the first output line to the second output line, both the first and second relays are set to normally open contact relays, with the first output line connected to the transformer secondary side at point A and the second output line connected to the secondary side at point B. The initial current path is: A → first disconnecting switch → common bus. First, the second relay is closed, and then the first disconnecting switch is turned off. At this time, the current path changes to: B → second relay → first current limiter → common bus. Then, the second disconnecting switch is closed, and the current path changes to: B → second disconnecting switch → common bus, thus realizing a single node switching operation.

[0026] Preferably, the controller includes a load metering unit, a voltage stabilizing drive unit, and a relay group. The relay group is used to control the opening and closing of the bidirectional oil valve mechanism and the switching of the electronic switching sub-device. The load metering unit is used to acquire voltage fluctuation data at the load end. The voltage stabilizing drive unit calculates the required voltage regulation range and the corresponding voltage value based on the voltage fluctuation data, and then drives the hydraulic drive device to achieve voltage regulation.

[0027] The beneficial effects of this invention are as follows: This solution designs a vacuum on-load variable voltage regulating device. By designing a hydraulic drive device to perform segmented, mechanical, wide-range, precise voltage regulation, and matching it with an electronic switching device for on-load switching, the voltage regulation range is expanded while significantly improving the stability and safety during voltage regulation. By establishing a mapping between the number of turns of the secondary adjustable coil and the load plate, the conversion relationship can be obtained to determine the number of turns per unit stroke, and correspondingly, the range of adjustable voltage per unit stroke. The load ratio characterizes the adjustable voltage value per unit stroke, thereby realizing the conversion from stepped voltage regulation to stepless voltage regulation, and thus achieving a significant improvement from coarse to fine voltage adjustment.

[0028] The above description of the invention is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0029] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. The drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0030] Figure 1 This is a schematic diagram of the structure of a vacuum on-load variable pressure regulating device according to the present invention.

[0031] Figure 2 This is a partial structural schematic diagram of a vacuum on-load variable pressure regulating device according to the present invention.

[0032] Explanation of markings in the diagram: 11-Transformer oil chamber, 12-Transformer secondary coil, 13-Transformer primary coil, 201-Oil guide pipe, 202-Return pipe, 203-Filter chamber, 204-First oil chamber, 205-Second oil chamber, 206-First oil pump, 207-Second oil pump, 208-First oil delivery pipe, 209-Second oil delivery pipe, 210-Two-way oil valve, 3-Voltage regulating device, 31-Load plate, 32-First voltage regulating sub-device, 33-Second voltage regulating sub-device, 34-Third voltage regulating sub-device, 35-Fourth voltage regulating sub-device. 36-First bidirectional oil valve, 37-Second bidirectional oil valve, 321-First pressure regulating chamber, 322-First driving chamber, 323-First moving block, 324-Conductive head, 41-First on-load switching sub-mechanism, 42-Second on-load switching sub-mechanism, 43-Third on-load switching sub-mechanism, 44-Fourth on-load switching sub-mechanism, 45-First disconnecting switch, 46-Second disconnecting switch, 47-Common bus, 48-First output line, 49-Second output line, 411-First relay, 412-Second relay, 413-First current limiter. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only one preferred embodiment of this invention and are only used to explain this invention. They do not limit the scope of protection of this invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations (or steps) can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but it may also have additional steps not included in the figures; the process may correspond to a method, function, procedure, subroutine, subroutine, etc.

[0035] Example: Figure 1As shown, a vacuum on-load variable voltage regulating device comprises a hydraulic drive device connected to the transformer oil chamber 11, a voltage regulating device 3 driven by the hydraulic drive device to adjust the number of turns of the transformer secondary coil 12, an electronic switching device for realizing on-load voltage regulation switching, and a controller. The hydraulic drive device and the electronic switching device are controlled by the controller. The voltage regulating device includes a plurality of voltage regulating sub-devices, and the electronic switching device includes the same number of electronic switching sub-devices as the voltage regulating sub-devices. The plurality of voltage regulating sub-devices and the corresponding electronic switching sub-devices constitute an on-load voltage regulating mechanism.

[0036] In this embodiment, the hydraulic drive device uses transformer oil as the power medium to cool the transformer oil while simultaneously filtering and cleaning it, thereby improving the safety and lifespan of the transformer. Since the voltage regulating sub-devices correspond to precise voltage regulation within a certain range, several sub-devices implement segmented voltage regulation. Driving the corresponding voltage regulating sub-devices through the hydraulic drive device allows for coarse-to-fine voltage regulation. During mechanical voltage regulation, the number of turns in the transformer's main winding 13 remains fixed, and the voltage ratio between the main and secondary sides of the transformer is equal to the ratio of the number of turns in the main and secondary windings. Therefore, adjusting the number of turns in the secondary winding participating in voltage regulation achieves the desired voltage regulation. To ensure stable output on the secondary side of the transformer, the corresponding electronic switching sub-device remains inactive. After the mechanical voltage regulation process is completed, the secondary side of the transformer needs to switch to the corresponding voltage value. Therefore, the electronic switching sub-device needs to operate according to the set logic to ensure rapid, safe, and reliable switching. Thus, this solution significantly improves the stability and safety of voltage regulation while expanding the voltage regulation range.

[0037] The hydraulic drive device consists of an oil guide pipe 201, a return pipe 202, a filter chamber 203, a first oil chamber 204, a second oil chamber 205, a first oil pump 206, a second oil pump 207, a first oil delivery pipe 208, a second oil delivery pipe 209, and a bidirectional oil valve mechanism for matching the voltage regulating device. The oil guide pipe connects the transformer oil chamber and the filter chamber. The first oil chamber and the second oil chamber are respectively connected to the filter chamber. The first oil pump is used to inject the transformer oil in the first oil chamber into the voltage regulating chamber of the voltage regulating device. The return pipe connects the voltage regulating chamber and the transformer oil chamber. Both the first oil delivery pipe and the second oil delivery pipe are equipped with bidirectional oil valve mechanisms. The second oil pump is connected to the first oil delivery pipe and the second oil delivery pipe through a two-way oil valve 210 to inject the transformer oil into the drive chamber of the voltage regulating device.

[0038] In this embodiment, the filter chamber can filter the transformer oil, making the transformer oil injected into the voltage regulating chamber cleaner and improving the arc extinguishing effect at the moment of voltage switching. At the same time, the filtered unclean transformer oil can be injected into the drive chamber as the driving power medium, effectively improving the utilization efficiency of waste oil. Both the first oil pipe and the second oil pipe are equipped with a bidirectional oil valve mechanism, which can ensure that the driving direction in each drive chamber is variable and adjustable.

[0039] As an optional embodiment, it also includes a refueling tank (not shown), an oil injection pipe (not shown), an oil level sensor (not shown), and a valve (not shown). The oil injection pipe connects the refueling tank and the first oil chamber for replenishing and cleaning transformer oil. The valve and the oil level sensor are electrically connected to the controller. The oil level sensor is installed inside the transformer to detect the transformer oil level. When the oil level is lower than a certain set value, the controller opens the valve to inject the transformer oil from the refueling tank into the first oil chamber. The transformer oil in the first oil chamber is then injected into the transformer by the first oil pump to replenish the transformer oil.

[0040] The voltage regulating device includes a load plate 31 and a first voltage regulating sub-device 32, a second voltage regulating sub-device 33, a third voltage regulating sub-device 34, and a fourth voltage regulating sub-device 35 disposed on the load plate. The load plate is connected to the secondary coil of the transformer to achieve stepless voltage regulation within ±20% of the rated voltage range according to the load ratio of the load plate. The corresponding electronic switching device includes a first electronic switching sub-device, a second electronic switching sub-device, a third electronic switching sub-device, and a fourth electronic switching sub-device.

[0041] In this embodiment, the first voltage regulating device, the second voltage regulating device, the third voltage regulating device, and the fourth voltage regulating device work together with the load plate to achieve segmented voltage regulation function. This segmented voltage regulation process involves the initial judgment (determining which segment the voltage value to be regulated belongs to) and the subsequent fine adjustment (the specific voltage value), which can significantly improve the efficiency of voltage regulation, and the voltage regulation range can be expanded through segmented voltage regulation.

[0042] like Figure 2 As shown, the first voltage regulating device, the second voltage regulating device, the third voltage regulating device, and the fourth voltage regulating device have the same structure. Specifically, the first voltage regulating device includes a first voltage regulating cavity 321, a first driving cavity 322, a first moving block 323 disposed in the first driving cavity, and a conductive head 324 fixedly connected to the first moving block. The contact of the conductive head abuts against the load plate. When the first moving block moves in the first driving cavity, it synchronously drives the conductive head to move on the load plate to achieve stepless voltage regulation.

[0043] In this embodiment, since the first, second, third, and fourth voltage regulating devices have the same structure, describing only the structure and connection relationship of the first voltage regulating device can be used to infer the structure and connection relationship of the other voltage regulating devices. When voltage regulation is required, the controller first determines which voltage regulation segment the voltage regulation value falls into. After determining the voltage regulation segment, it starts driving the drive chamber of the voltage regulating device. Specifically, by injecting transformer oil, a force is applied to the first drive block located in the first drive chamber, driving the first drive block to move a certain distance in a certain direction. The moving distance can be precisely controlled according to the amount of transformer oil injected, thereby achieving precise adjustment. Subsequently, the conductive head moves within the first voltage regulating chamber, and the contact of the conductive head moves a certain distance on the load plate, thus achieving precise voltage regulation.

[0044] The first, second, third, and fourth pressure regulating devices are all equipped with a bidirectional oil valve mechanism. The bidirectional oil valve mechanism includes a first bidirectional oil valve 36 and a second bidirectional oil valve 37. The first and second bidirectional oil valves are respectively connected to the first oil supply pipe and the second oil supply pipe. The first and second bidirectional oil valves are simultaneously closed or opened to drive the corresponding moving blocks in the first, second, third, or fourth pressure regulating devices to move in order to achieve pressure regulation.

[0045] In this embodiment, since the injected transformer oil is needed to provide thrust to the drive block in the drive cavity, a flow channel needs to be formed at both ends of the drive cavity. Therefore, a first bidirectional oil valve and a second bidirectional oil valve are configured on the external oil supply pipe of each drive cavity, that is, one end injects transformer oil and the other end discharges transformer oil, so as to ensure that the drive block can perform phase-fixed movement according to the direction of transformer oil injection.

[0046] The load ratio formula for the load plate is as follows:

[0047]

[0048] λ is the load ratio, U max The maximum adjustable voltage of the secondary coil, U min L is the minimum adjustable voltage of the secondary coil, and L is the effective length of the load plate.

[0049] In this embodiment, the voltage of the transformer is proportional to the turns ratio. Therefore, the number of turns of the adjustable coil is designed according to the adjustable range of the transformer. Then, the adjustable coil is used as the adjustable unit and a mapping is established with the load plate. That is, the number of turns corresponding to a unit stroke can be obtained through the conversion relationship, and the range of adjustable voltage corresponding to a unit stroke can be obtained. Therefore, the adjustable voltage value on a unit stroke is characterized by the load ratio, thereby realizing the conversion from stepped voltage regulation to stepless voltage regulation, or in other words, realizing the upgrade from coarse adjustment to fine adjustment.

[0050] like Figure 2 As shown, the electronic switching sub-device includes a first disconnecting switch 45, a second disconnecting switch 46, and an on-load switching sub-mechanism, as follows: Figure 1 As shown, the four switching sub-devices correspond to the on-load switching sub-mechanisms, including 41 first on-load switching sub-mechanism, 42 first on-load switching sub-mechanism, 43 first on-load switching sub-mechanism, and 44 first on-load switching sub-mechanism. The first disconnecting switch is installed on the first output line 48, and the second disconnecting switch is installed on the second output line 49. Both the first and second output lines are connected to the common bus 47. The first and second output lines are electrically connected to the on-load switching sub-mechanisms to achieve on-load switching.

[0051] In this embodiment, the voltage adjustment range between the first output line and the second output line is the voltage adjustment range of the first voltage regulating device. The mechanical voltage adjustment of the first voltage regulating device has been described above and will not be repeated here. After the mechanical voltage adjustment process is completed, the voltage output needs to be switched from the first output line to the second output line through the on-load switching submechanism. The controller makes precise adjustments according to the set logic.

[0052] The on-load switching submechanism includes a first relay 411, a second relay 412, and a first current limiter 413. The first end of the first relay is electrically connected to the first output line, the first end of the second relay is electrically connected to the second output line, the second ends of the first relay and the second end of the second relay are both electrically connected to the first end of the first current limiter, and the second end of the first current limiter is electrically connected to the common bus.

[0053] In this embodiment, precise switching can be achieved through the connection structure of the components of the on-load switching submechanism and the control logic of the controller. For example, when it is necessary to switch the voltage output from the first output line to the second output line, the first relay and the second relay are both normally open contact relays, and the connection point A between the first output line and the secondary side of the transformer and the connection point B between the second output line and the secondary side are set. The initial current path is: A → first disconnecting switch → common bus. First, the second relay is closed, and then the first disconnecting switch is turned off. At this time, the current path becomes: B → second relay → first current limiter → common bus. Then the second disconnecting switch is closed, and the current path becomes: B → second disconnecting switch → common bus, realizing a single node switching operation.

[0054] The controller includes a load metering unit, a voltage stabilizing drive unit, and a relay group. The relay group is used to control the opening and closing of the bidirectional oil valve mechanism and the switching of the electronic switching sub-device. The load metering unit is used to acquire voltage fluctuation data at the load end. The voltage stabilizing drive unit calculates the required voltage regulation range and the corresponding voltage value based on the voltage fluctuation data, and then drives the hydraulic drive device to achieve voltage regulation.

[0055] The specific embodiments described above are preferred embodiments of a vacuum on-load variable voltage regulating device of the present invention, and are not intended to limit the specific scope of the present invention. The scope of the present invention includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the shape and structure of the present invention are within the protection scope of the present invention.

Claims

1. A vacuum on-load variable voltage regulating device, characterized in that: The device includes a hydraulic drive unit connected to the transformer oil chamber, a voltage regulating device driven by the hydraulic drive unit to adjust the number of turns in the transformer secondary coil, an electronic switching device for realizing on-load voltage regulation, and a controller. The hydraulic drive unit and the electronic switching device are controlled by the controller. The voltage regulating device includes several voltage regulating sub-devices, and the electronic switching device includes the same number of electronic switching sub-devices as the voltage regulating sub-devices. The several voltage regulating sub-devices and the corresponding electronic switching sub-devices constitute an on-load voltage regulating mechanism. The hydraulic drive device includes an oil guide pipe, a return pipe, a filter chamber, a first oil chamber, a second oil chamber, a first oil pump, a second oil pump, a first oil delivery pipe, a second oil delivery pipe, and a bidirectional oil valve mechanism matching the voltage regulating device. The oil guide pipe connects the transformer oil chamber and the filter chamber. The first oil chamber and the second oil chamber are respectively connected to the filter chamber. The first oil pump is used to inject the transformer oil in the first oil chamber into the voltage regulating chamber of the voltage regulating device. The return pipe connects the voltage regulating chamber and the transformer oil chamber. Both the first oil delivery pipe and the second oil delivery pipe are equipped with bidirectional oil valve mechanisms. The second oil pump is connected to the first oil delivery pipe and the second oil delivery pipe respectively through a two-way oil valve to inject the transformer oil into the drive chamber of the voltage regulating device.

2. The vacuum on-load variable voltage regulating device according to claim 1, characterized in that: The voltage regulating device includes a load plate and a first voltage regulating device, a second voltage regulating device, a third voltage regulating device, and a fourth voltage regulating device disposed on the load plate. The load plate is connected to the secondary coil of the transformer and is used to achieve stepless voltage regulation within a rated voltage range of ±20% according to the load ratio of the load plate.

3. A vacuum on-load variable voltage regulating device according to claim 2, characterized in that: The first, second, third, and fourth voltage regulating devices have the same structure. The first voltage regulating device includes a first voltage regulating cavity, a first driving cavity, a first moving block disposed in the first driving cavity, and a conductive head fixedly connected to the first moving block. The contact of the conductive head abuts against the load plate. When the first moving block moves in the first driving cavity, it synchronously drives the conductive head to move on the load plate to achieve stepless voltage regulation.

4. A vacuum on-load variable voltage regulating device according to claim 3, characterized in that: The first, second, third, and fourth pressure regulating devices are all equipped with a bidirectional oil valve mechanism. The bidirectional oil valve mechanism includes a first bidirectional oil valve and a second bidirectional oil valve. The first and second bidirectional oil valves are respectively connected to the first oil supply pipe and the second oil supply pipe. The first and second bidirectional oil valves are simultaneously closed or opened to drive the corresponding moving blocks in the first, second, third, or fourth pressure regulating devices to move in order to achieve pressure regulation.

5. A vacuum on-load variable voltage regulating device according to claim 2, characterized in that: The load ratio formula for the load plate is as follows: ; For load ratio, The maximum adjustable voltage of the secondary coil This is the minimum adjustable voltage for the secondary coil. L This is the effective length of the load plate.

6. A vacuum on-load variable voltage regulating device according to claim 1, characterized in that: The electronic switching sub-device includes a first disconnecting switch, a second disconnecting switch, and an on-load switching sub-mechanism. The first disconnecting switch is disposed on the first output line, and the second disconnecting switch is disposed on the second output line. Both the first and second output lines are connected to a common bus. The on-load switching sub-mechanism is electrically connected between the first and second output lines to realize on-load switching. The on-load switching submechanism includes a first relay, a second relay, and a first current limiter. The first terminal of the first relay is electrically connected to the first output line, the first terminal of the second relay is electrically connected to the second output line, the second terminals of the first relay and the second terminal of the second relay are both electrically connected to the first terminal of the first current limiter, and the second terminal of the first current limiter is electrically connected to the common bus.

7. A vacuum on-load variable voltage regulating device according to claim 6, characterized in that: The controller includes a load metering unit, a voltage stabilizing drive unit, and a relay group. The relay group is used to control the opening and closing of the bidirectional oil valve mechanism and the switching of the electronic switching sub-device. The load metering unit is used to acquire voltage fluctuation data at the load end. The voltage stabilizing drive unit calculates the required voltage regulation range and the corresponding voltage value based on the voltage fluctuation data, and then drives the hydraulic drive device to achieve voltage regulation.

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