Intelligent power distribution transformer with load regulation and voltage regulation functions

Abstract

The application belongs to the technical field of transformers, and particularly relates to an intelligent power distribution transformer with a load-regulated capacity-regulated voltage regulating function; the intelligent power distribution transformer comprises a mounting frame for mounting the transformer, a transformer core provided with a main core column and a side core column, a high-voltage winding arranged on the main core column, a low-voltage winding arranged on the main core column, wherein the low-voltage winding adopts a double-split structure and comprises a first winding and a second winding, a load switching unit connected with a voltage dividing connector, the first winding and the second winding respectively, and the load switching unit comprising a thyristor valve group and a vacuum switch, a magnetic control reactor unit arranged on the side core column, and an intelligent control unit for collecting electrical data and executing a predictive control algorithm; the load switching unit of the application comprises the thyristor valve group and the vacuum switch, and in the process of switching the voltage dividing connector and reconstructing the series-parallel connection of the low-voltage winding, the arcless transition in the electrical switching process is realized through the cooperation of the thyristor valve group and the vacuum switch.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to an intelligent distribution transformer with on-load capacity and voltage regulation functions. Background Technology

[0002] With the increasing diversification of electricity loads and the widespread integration of distributed energy resources, the requirements for power supply quality, operational efficiency, and reliability in distribution networks are constantly increasing. As a key piece of equipment in the distribution network, the operating performance of distribution transformers directly affects the power supply quality and loss level of the entire system. In actual operation, distribution transformers often face problems such as large load fluctuations and significant voltage deviations. For example, in residential or commercial areas, the daily load peak-valley difference is large. If a fixed-capacity transformer is used, the no-load loss ratio is high during light-load periods, resulting in energy waste. Simultaneously, when the load changes or the voltage of the upstream grid fluctuates, the transformer output voltage is prone to deviate from the rated value, affecting the power quality for users. Therefore, distribution transformers with capacity and voltage regulation functions have become an important technological development direction.

[0003] In existing technologies, capacity-adjustable transformers typically change their capacity by altering the series-parallel connection structure of the low-voltage winding, while voltage-adjustable transformers regulate their output voltage by changing the voltage divider terminals of the high-voltage winding. However, traditional mechanical on-load tap changers suffer from problems such as mechanical wear, arc erosion, slow response speed, and high maintenance costs during operation, making it difficult to meet the demands of frequent adjustments and intelligent control. Furthermore, inrush currents or reactive power surges may occur during capacity or voltage adjustment switching, affecting the stable operation of the transformer itself and the power grid. How to effectively suppress inrush currents, achieve a smooth transition, and deeply integrate with the transformer body and control system during switching remains a pressing technical challenge. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an intelligent distribution transformer with on-load capacity and voltage regulation functions, aiming to solve the problems in the background technology.

[0005] To achieve the above-mentioned technical objectives, the specific technical solution of the present invention is as follows: The intelligent distribution transformer with on-load capacity and voltage regulation function proposed in the present invention includes: a mounting frame for mounting the transformer; a transformer core fixedly mounted on the mounting frame, wherein the transformer core is provided with a main core column and a side core column; a high-voltage winding disposed on the main core column, wherein the high-voltage winding is provided with multiple voltage divider terminals; a low-voltage winding disposed on the main core column, wherein the low-voltage winding adopts a double-split structure, including a first winding and a second winding; a high-voltage bushing and a low-voltage bushing, mounted above the mounting frame; an on-load switching unit connected to the voltage divider terminals, the first winding and the second winding respectively, wherein the on-load switching unit includes a thyristor valve group and a vacuum switch, and the on-load switching unit is used to realize arc-free transition during the switching of voltage divider terminals and the series-parallel reconfiguration process of the low-voltage winding; a magnetically controlled reactor unit disposed on the side core column; and an intelligent control unit for collecting electrical data and executing predictive control algorithms to control the coordinated operation of the on-load switching unit and the magnetically controlled reactor unit.

[0006] Preferably, the vacuum switch includes an electromagnetic drive coil, a metal disk, and a vacuum interrupter; the vacuum interrupter is provided with a stationary contact rod, a stationary contact, a moving contact rod, and a moving contact, the moving contact rod being fixedly connected to the metal disk, and the electromagnetic drive coil being used to drive the metal disk to move.

[0007] Preferably, a bellows is sealed between the moving contact rod and the vacuum interrupter, and a shielding cylinder is provided inside the vacuum interrupter.

[0008] Preferably, a fixed end cover plate and a moving end cover plate are fixedly connected to both ends of the vacuum interrupter, and a guide sleeve that cooperates with the moving contact rod is fixedly connected to the moving end cover plate.

[0009] Preferably, the magnetically controlled reactor unit includes a DC excitation winding for providing reactive power support and suppressing inrush current during capacity and voltage regulation operations.

[0010] Preferably, the on-load switching unit further includes a connecting frame, on which the thyristor valve group and the vacuum switch are mounted, and a heat dissipation structure is installed on one side of the thyristor valve group.

[0011] Preferably, an oil reservoir is installed above the mounting frame, and heat dissipation fins are installed on one side of the mounting frame for transformer heat dissipation.

[0012] Preferably, the intelligent control unit includes: The main control processing module, composed of a digital signal processor or microcontroller, is used for data acquisition, algorithm calculation, logic judgment and communication. The signal acquisition and conditioning module is used to monitor the operating status of the transformer in real time and convert analog signals into digital signals for use by the main control processing module; The drive and execution interface module is used to drive the vacuum switch and adjust the current of the DC excitation winding.

[0013] The communication and human-machine interaction module is used to realize transformer data exchange, remote control, and status visualization.

[0014] Preferably, the signal acquisition and conditioning module monitors the transformer's operating status, including: voltage and current waveforms on the high-voltage and low-voltage sides; the opening and closing status of the vacuum interrupter; the temperature of the thyristor valve group; and the magnitude of the DC excitation winding current.

[0015] The beneficial effects of this invention are as follows: 1. This invention includes an on-load switching unit comprising a thyristor valve assembly and a vacuum switch. During voltage divider switching and low-voltage winding series-parallel reconfiguration, the thyristor valve assembly and vacuum switch work together to achieve arc-free transition during electrical switching. Compared to traditional mechanical on-load tap changers, this invention effectively avoids contact erosion and arc generation, significantly improves the electrical life and operational reliability of the switch, and reduces equipment maintenance frequency.

[0016] 2. The present invention sets up a magnetically controlled reactor unit on the side core column of the transformer core. The unit includes a DC excitation winding. During the operation of capacity adjustment or voltage adjustment, the intelligent control unit controls the magnetically controlled reactor unit to work together to provide reactive power support and effectively suppress excitation inrush current, thereby avoiding the current impact on the transformer body and the power grid at the moment of switching and ensuring the smoothness of the switching process and the stability of the system.

[0017] In summary, this invention, through an intelligent control unit, coordinates the arc-free switching technology of the on-load switching unit with the reactive power support and inrush current suppression technology of the magnetically controlled reactor to form a linkage mechanism: before the switching action occurs, the magnetically controlled reactor pre-establishes a compensation environment, and then the on-load switching unit performs arc-free switching. The two are precisely coordinated in timing, and together they achieve the outstanding technical effect of smooth on-load capacity and voltage regulation of the distribution transformer without arc, inrush current, or impact on the power grid under load fluctuation and voltage deviation conditions. This solves the problems of unstable switching process, large impact, and short lifespan of traditional solutions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the transformer of the present invention.

[0019] Figure 2 This is a front view schematic diagram of the transformer of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of the on-load switching unit proposed in this invention.

[0021] Figure 4This is a front view schematic diagram of the on-load switching unit proposed in this invention.

[0022] Figure 5 This is a schematic diagram of the vacuum interrupter structure proposed in this invention.

[0023] Figure 6 This is a structural diagram of the intelligent control unit system proposed in this invention.

[0024] The corresponding names of the attached figures are as follows: 1. Mounting frame; 2. Transformer core; 21. Main core column; 22. Side core column; 3. Low-voltage winding; 4. High-voltage winding; 5. Magnetically controlled reactor unit; 6. On-load switching unit; 7. High-voltage bushing; 8. Low-voltage bushing; 9. Heat sink fins; 10. Intelligent control unit; 11. Oil reservoir; 61. Connecting frame; 62. Thyristor valve group; 63. Vacuum interrupter; 64. Electromagnetic drive coil; 65. Metal disc; 66. Heat dissipation structure; 631. Stationary contact rod; 632. Fixed end cover plate; 633. Stationary contact; 634. Moving contact; 635. Shielding cylinder; 636. Bellows; 637. Moving contact rod; 638. Moving end cover plate; 639. Guide sleeve. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0026] This embodiment provides an intelligent distribution transformer with on-load capacity and voltage regulation functions, such as... Figures 1-6As shown, its overall structure is as follows: mounting frame 1, transformer core 2, high-voltage winding 4, low-voltage winding 3, on-load switching unit 6, magnetically controlled reactor unit 5, and intelligent control unit 10; the mounting frame 1 is welded from channel steel or steel plate, and has mounting holes at the bottom for fixing the transformer to an outdoor pole or indoor platform; an oil reservoir 11 is fixed above the mounting frame to provide space for the transformer oil to expand due to heat and to achieve a sealed oil replenishment function. The oil reservoir 11 is equipped with an oil level gauge and a dehumidifier to monitor oil level changes and keep the oil dry; the transformer core 2 includes a main core column 21 and a side core column 22. The core is made of high-permeability cold-rolled silicon steel sheets. The main core column is used to arrange the high and low voltage windings, and the side core column is used to install the magnetically controlled reactor unit. Specifically, the high-voltage winding 4 and the low-voltage winding 3 are concentrically mounted on the main core column 21. An insulating cylinder is provided between the high-voltage and low-voltage windings. The high-voltage winding 4 is equipped with multiple voltage divider joints. The low-voltage winding adopts a double-split structure, that is, the first winding and the second winding have the same number of turns and symmetrical structure. They are respectively led out with terminals and connected to the on-load switching unit through external copper busbars. The transformer body adopts an oil-immersed self-cooling method. Heat dissipation fins 9 are installed on one side of the mounting frame. The fins are made of thin steel plate pressed and welded to the outer wall of the oil tank to increase the heat dissipation area. A high-voltage bushing 7 and a low-voltage bushing 8 are also installed above the mounting frame 1.

[0027] like Figures 3-5 As shown, the on-load switching unit 6 is mounted on the connecting frame 61, which is fixed above or to the side of the transformer body for easy connection of the lead wires. The on-load switching unit 6 includes a thyristor valve group 62 and a vacuum switch. The thyristor valve group 62 adopts a bidirectional thyristor or anti-parallel thyristor form, with each phase independently packaged and equipped with an RC snubber circuit to suppress overvoltage. A heat dissipation structure 66 is installed on one side of the thyristor valve group 62. The heat dissipation structure can adopt an aluminum alloy heat sink or forced air cooling to ensure that the junction temperature of the thyristor does not exceed the allowable value during frequent switching. The vacuum switch includes an electromagnetic drive coil 64, a metal disk 65, and a vacuum interrupter 63. The electromagnetic drive coil is wound with copper wire and cooperates with the metal disk to form an electromagnetic repulsion mechanism, which can realize millisecond-level opening and closing actions.

[0028] Specifically, such as Figure 5 As shown, the vacuum interrupter 63 has the following structure: a stationary contact rod 631 is fixed to a fixed end cover plate 632, and a stationary contact 633 is provided at its end; a moving contact rod 637 is fixedly connected to a metal disk 65, and a moving contact 634 is provided at its end; a bellows pipe 636 is used to seal the moving contact rod and the vacuum interrupter; a shielding cylinder 635 is arranged around the contact area to absorb the metal vapor generated during interruption; a guide sleeve 639 is installed on the moving end cover plate 638 to ensure the linearity of the moving contact rod's movement.

[0029] The electrical connections in this embodiment are as follows: For high-voltage side voltage regulation: each voltage divider is connected to the corresponding thyristor valve group 62 and vacuum switch combination, with the common terminal led out to the high-voltage output terminal; For low-voltage side capacity regulation: the beginning and end of the first winding and the second winding are respectively connected to the on-load switching unit 6, and parallel large-capacity or series small-capacity connection is achieved through the switching of the thyristor valve group 62 and the vacuum switch; the switching process is controlled by the intelligent control unit, following the principle of "thyristor first turn on, vacuum switch last; vacuum switch first turn off, thyristor last turn off"; the specific closing and opening sequence is as follows: Closing transition: first trigger the thyristor valve group 62 to conduct, and after the current is transferred to the thyristor branch, the vacuum switch closes, and then the thyristor valve group 62 exits conduction; Opening transition: first trigger the thyristor valve group 62 to conduct, the vacuum switch opens, and after the arc is extinguished, the thyristor valve group 62 is delayed to turn off. This timing ensures that the mechanical contacts are not arc-eroded during operation, extending electrical life.

[0030] Preferably, the thyristor valve group 62 is first triggered to conduct, and after a short delay, such as 1-2ms, the current is allowed to naturally commutate to the thyristor branch, or the vacuum switch is controlled to close after the current flowing through the vacuum switch is detected to be zero; after the closing is completed, the thyristor valve group 62 is turned off after a delay.

[0031] In this embodiment, the magnetically controlled reactor unit 5 is mounted on the side core column 22 and includes a DC excitation winding made of insulated copper wire, which is mounted on the side core column and connected to the low-voltage side or an independent DC power supply via a rectifier module. By adjusting the magnitude of the DC excitation current, the magnetic saturation degree of the side core column is changed, thereby adjusting the equivalent inductance value of the reactor and achieving continuous regulation of reactive power. Before the capacity or voltage adjustment operation, the intelligent control unit 10 adjusts the DC excitation current in advance to make the reactor operate in the required reactive power output state, which is used to suppress voltage fluctuations and inrush currents during switching.

[0032] In this embodiment, the intelligent control unit 10 is installed inside the transformer control box and adopts a modular design, including the following functional modules: Main control processing module: Selects a 32-bit digital signal processor (DSP) or an ARM Cortex-M series microcontroller with a main frequency of not less than 100 MHz, and has built-in flash memory and RAM for running predictive control algorithms, logic judgments, data storage and communication protocol stack.

[0033] The signal acquisition and conditioning module acquires data including: voltage and current acquisition: using precision voltage and current transformers, high and low voltage and current signals are converted into analog signals within a ±5V range, which are then fed into the ADC after anti-aliasing filtering; status quantity acquisition: the opening and closing status of the vacuum interrupter is connected to the optocoupler isolation input through auxiliary contacts; thyristor valve group temperature is acquired through a PT100 or digital temperature sensor; DC excitation winding current is detected through a Hall current sensor. All analog signals are converted into digital quantities by the ADC, with a sampling frequency of not less than 12.8 kHz to ensure harmonic analysis accuracy.

[0034] Drive and execution interface modules: Vacuum switch drive: Controls the on / off state of the electromagnetic drive coil through IGBT or MOSFET drive circuit to achieve millisecond-level opening and closing; Thyristor valve group 62 trigger: Employs a trigger circuit isolated by a pulse transformer to ensure reliable triggering of the thyristor when it needs to conduct; DC excitation regulation: Regulates the DC excitation winding current through PWM control of the DC / DC converter, with a response time of no more than 10 ms.

[0035] Communication and Human-Machine Interaction Module: Supports RS-485, Ethernet or 4G / 5G wireless communication interfaces, and adopts ModbusRTU, IEC 60870-5-104 or IEC 61850 protocols to realize data exchange with the distribution automation master station.

[0036] Implementation of the predictive control algorithm: To achieve smooth switching between on-load capacity and voltage regulation, the intelligent control unit incorporates a cooperative control algorithm based on model predictive control (MPC). The specific steps are as follows: Data preprocessing: Fast Fourier Transform (FFT) is performed on the acquired voltage and current waveforms to extract the fundamental amplitude, harmonic content, and power factor.

[0037] Status Judgment: Based on the load factor and voltage deviation, determine whether capacity or voltage adjustment is required. Capacity derating is triggered when the load factor is below a set threshold (e.g., 30%); voltage adjustment is triggered when the voltage deviation exceeds a set range (e.g., ±5%).

[0038] Switching timing prediction: Based on the current zero-crossing point, harmonic phase, and the state of the magnetically controlled reactor, the optimal switching time is predicted to minimize the impact of switching on the power grid.

[0039] Coordinated execution: First, adjust the DC excitation current to a predetermined value so that the magnetically controlled reactor outputs the required reactive power. Then, the on-load switching unit is controlled according to the timing sequence to complete the winding series-parallel reconfiguration or voltage divider switching; after the switching is completed, closed-loop regulation is performed according to voltage and reactive power feedback until the system enters steady state.

[0040] Fault self-check: If an abnormality such as timeout, failure to operate, or overcurrent occurs during the switching process, the subsequent actions will be immediately blocked and an alarm will be issued. At the same time, the event log will be uploaded to the main station.

[0041] This embodiment takes switching from "small capacity mode" to "large capacity mode" as an example. The specific implementation steps are as follows: The intelligent control unit 10 monitors in real time that the load on the low-voltage side continues to increase, reaching the capacity switching threshold, and predicts that the load will continue to rise within the next 30 seconds. The main control module first adjusts the DC excitation current of the magnetically controlled reactor to make the reactor output inductive reactive power, suppressing the voltage drop at the moment of switching. The on-load switching unit 6 is then controlled to perform the switching: the thyristor valve group 62 is triggered to conduct, temporarily connecting the first winding and the second winding in parallel through the thyristor to form a transition path; the vacuum switch is closed to complete the permanent parallel connection; the thyristor valve group 62 is turned off after a delay, and the switching is completed. After the switching, the intelligent control unit 10 monitors the voltage and current on the low-voltage side, confirms the successful mode conversion, and stores and uploads the action record. If an abnormal voltage or current surge is detected during the switching process, the system automatically returns to the original mode and issues an alarm.

[0042] Preferably, if the main control processing module does not receive the corresponding status feedback from the signal acquisition and conditioning module within a set time, such as 5ms, after issuing the opening or closing command, it is determined that the switch action is abnormal, the subsequent switching process is immediately blocked, and a fault alarm is issued through the communication and human-machine interaction module.

[0043] Finally, it should be noted that in the description of this invention, the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intelligent distribution transformer with on-load capacity and voltage regulation functions, characterized in that, include: Mounting bracket (1) is used to install the transformer; The transformer core (2) is fixedly installed on the mounting frame (1), and the transformer core (2) is provided with a main core column (21) and a side core column (22). The high voltage winding (4) is set on the main core column (21), and the high voltage winding (4) is provided with multiple voltage divider joints; The low-voltage winding (3) is set on the main core column (21). The low-voltage winding (3) adopts a double-split structure, including a first winding and a second winding. High-pressure bushing (7) and low-pressure bushing (8) are installed above the mounting bracket (1); The on-load switching unit (6) is connected to the voltage divider, the first winding and the second winding respectively. The on-load switching unit includes a thyristor valve group (62) and a vacuum switch. The on-load switching unit is used to realize the arc-free transition in the process of switching the voltage divider and reconfiguring the series and parallel connection of the low-voltage winding (3). A magnetically controlled reactor unit (5) is disposed on the side core column (22); The intelligent control unit (10) is used to collect electrical data and execute predictive control algorithms to control the coordinated operation of the on-load switching unit (6) and the magnetically controlled reactor unit (5).

2. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 1, characterized in that, The vacuum switch includes an electromagnetic drive coil (64), a metal disk (65), and a vacuum interrupter (63); the vacuum interrupter (63) is provided with a stationary contact rod (631), a stationary contact (633), a moving contact rod (637), and a moving contact (634). The moving contact rod (637) is fixedly connected to the metal disk (65), and the electromagnetic drive coil (64) is used to drive the metal disk (65) to move.

3. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 2, characterized in that, A bellows (636) is sealed between the moving contact rod (637) and the vacuum interrupter (63), and a shielding cylinder (635) is provided inside the vacuum interrupter (63).

4. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 2, characterized in that, The vacuum interrupter (63) is fixedly connected to a fixed end cover plate (632) and a moving end cover plate (638) at both ends, and a guide sleeve (639) that cooperates with the moving contact rod (637) is fixedly connected to the moving end cover plate (638).

5. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 1, characterized in that, The magnetically controlled reactor unit (5) includes a DC excitation winding, which is used to provide reactive power support and suppress excitation inrush current during capacity and voltage regulation operations.

6. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 1, characterized in that, The on-load switching unit (6) also includes a connecting frame (61), the thyristor valve group (62) and the vacuum switch are mounted on the connecting frame (61), and a heat dissipation structure (66) is installed on one side of the thyristor valve group (62).

7. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 1, characterized in that, An oil storage tank (11) is installed above the mounting frame (1), and a heat dissipation fin (9) is installed on one side of the mounting frame (1) for transformer heat dissipation.

8. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 5, characterized in that, The intelligent control unit (10) includes: The main control processing module, composed of a digital signal processor or microcontroller, is used for data acquisition, algorithm calculation, logic judgment and communication. The signal acquisition and conditioning module is used to monitor the operating status of the transformer in real time and convert analog signals into digital signals for use by the main control processing module; The drive and execution interface module is used to drive the vacuum switch and adjust the current of the DC excitation winding. The communication and human-machine interaction module is used to realize transformer data exchange, remote control, and status visualization.

9. The intelligent distribution transformer with on-load capacity and voltage regulation function according to claim 8, characterized in that, The signal acquisition and conditioning module monitors the transformer's operating status, including: voltage and current waveforms on the high-voltage and low-voltage sides; opening and closing status of the vacuum interrupter; temperature of the thyristor valve group (62); and magnitude of the DC excitation winding current.

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