A high-energy-efficiency intelligent hybrid distribution area power distribution terminal voltage management device

Abstract

The application relates to the technical field of power distribution equipment, and discloses a high-energy-efficiency intelligent hybrid type terminal voltage management device for distribution areas, which comprises a current and voltage sampling module, an intelligent voltage regulating controller module, a voltage regulating transformer module and an intelligent capacitor bank connected to a terminal line of a distribution area; further comprises an environment regulation unit, a safety protection unit, a seamless bypass unit and an Internet of Things remote control device; the current and voltage sampling module is used for collecting electrical parameters of the distribution line, and the intelligent voltage regulating controller module is used for overall planning and control of the voltage regulating transformer module and the intelligent capacitor; the terminal voltage regulation and dynamic reactive power compensation are realized; the device is combined with hierarchical temperature control, low-temperature anti-freezing, multi-stage safety protection and Internet of Things remote control; the device has local man-machine interaction and fault bypass switching functions, is reliable in operation, high in integration, strong in intelligence and wide in adaptability, and is suitable for terminal voltage management and power quality optimization of various urban and rural low-voltage distribution areas.

Description

Technical Field

[0001] This invention relates to the field of power distribution equipment technology, specifically to a high-efficiency intelligent hybrid distribution terminal voltage management device. Background Technology

[0002] With the continuous growth of electricity load in urban and rural areas, a large number of distributed photovoltaic (PV) systems, new energy vehicle charging facilities, and various nonlinear loads are being connected to low-voltage distribution networks, making the problem of day-night voltage fluctuations in distribution substations increasingly prominent. During the day, the grid-connected power generation of distributed PV generates reverse current, which can easily lead to excessive voltage rises at the end of the substation lines. At night, after PV power generation stops, high-power loads are concentrated, increasing line voltage drop and causing a significant drop in end-point voltage, resulting in bidirectional voltage exceeding limits both day and night. At the same time, some rural substations have problems such as large power supply radius, thin line diameter, and large load fluctuations, leading to frequent low voltage phenomena, which seriously affect the reliability of power supply and the service life of electrical equipment.

[0003] Currently, the equipment for addressing voltage issues at the end of distribution transformer areas is mainly divided into two categories: one is single voltage regulating equipment, such as on-load tap changers and line tap changers, which can directly adjust the voltage amplitude but cannot improve the power factor of the transformer area or reduce reactive power losses in the lines. Furthermore, frequent voltage regulation can lead to a shortened tap changer life and high operating losses. The other category is single reactive power compensation equipment, such as intelligent capacitors and static var generators, which can increase voltage by compensating for reactive power and reduce line losses. However, the voltage regulation range is limited, and it cannot meet the management requirements when the voltage deviation is too large.

[0004] Some existing hybrid voltage regulation devices simply combine voltage regulation equipment and reactive power compensation equipment. These two systems are controlled independently, lacking a unified and coordinated control strategy. This makes them highly susceptible to control oscillations, where voltage regulation leads to overcompensation and compensation causes voltage fluctuations. Voltage regulation accuracy is poor, equipment operates frequently, and mechanical losses are high. Furthermore, existing devices generally have weak environmental adaptability, only equipped with conventional axial air cooling and lacking low-temperature antifreeze and condensation prevention mechanisms. In cold and humid northern regions during winter, condensation, icing, and component freezing damage are common. In southern regions during hot and heavy summers, overheating is also a concern. Hot shutdown results in poor reliability during outdoor operation. Furthermore, the existing equipment protection system is incomplete, possessing only basic electrical protection, lacking lightning surge protection, module-level independent protection, and physical protection layers. This leads to a high failure rate and short equipment lifespan in outdoor scenarios with frequent lightning strikes, humidity, and external interference. Most devices only support local button debugging and lack comprehensive IoT remote control capabilities, making it impossible to achieve real-time monitoring of operating status, fault early warning, and remote parameter setting. The urban and rural power distribution substations are scattered and numerous, requiring frequent on-site inspections by maintenance personnel, resulting in high maintenance costs and slow fault response. Summary of the Invention

[0005] The purpose of this invention is to provide a high-efficiency intelligent hybrid distribution terminal voltage management device, which solves the problems pointed out in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a high-efficiency intelligent hybrid distribution terminal voltage management device, comprising a current and voltage sampling module connected to the distribution terminal line, an intelligent voltage regulator module, a voltage regulator transformer module, and an intelligent capacitor bank; It also includes an environmental control unit, a safety protection unit, a seamless bypass unit, and an Internet of Things remote control device; The voltage regulator module incorporates a hierarchical collaborative control algorithm module and a multi-level anti-oscillation logic module. The system adopts a dual-dimensional voltage regulation architecture of reactive power compensation and transformer voltage regulation in parallel and collaborative manner, classifying and precisely addressing high and low voltage issues: fault diversion and independent regulation are achieved based on the cause of voltage drops. Specifically, low voltage caused by insufficient reactive power is compensated by intelligent capacitor banks switching reactive power to quickly raise the voltage; high and low voltage caused by lack of active power or low overall grid amplitude are mitigated by the voltage regulating transformer module, which performs amplitude-level voltage regulation as a fallback. The two types of regulation units work in parallel, each performing its own function, respectively addressing reactive and active voltage drops, achieving refined and differentiated closed-loop management of voltage deviations.

[0007] The environmental control unit adopts a three-level temperature control architecture, with the temperature and humidity control module as the core, which links the heat dissipation module, the intelligent cooling module and the auxiliary heater. It also has the functions of high-temperature graded heat dissipation and low-temperature antifreeze and dehumidification. The safety protection unit includes four levels of protection: surge protection, electrical protection, module protection, and physical protection. The seamless bypass unit adopts a topology structure of parallel power electronic switches and mechanical switches for seamless switching of power supply to the transformer substation during maintenance.

[0008] Preferably, the current and voltage sampling module uses current transformers and voltage transformers with an accuracy of not less than 0.2, and a sampling period of not more than 20ms. It can collect three-phase voltage, three-phase current, power factor, active power, reactive power and three-phase unbalance parameters in real time, and the output terminal is electrically connected to the signal input terminal of the intelligent voltage regulator.

[0009] Preferably, the intelligent voltage regulator controller adopts a 32-bit industrial-grade ARM main control chip, which integrates a data acquisition and processing unit, a voltage regulation control unit, a bypass control unit, a protection logic unit, a human-machine interaction unit, an algorithm calculation unit, and a communication unit. The voltage regulation control unit is electrically connected to the actuator of the voltage regulation transformer module and is used to issue voltage regulation level commands; the bypass control unit is electrically connected to the seamless bypass unit and is used to trigger bypass switching actions; the protection logic unit is linked with the safety protection unit and is used for fault determination and protection action triggering; the human-machine interaction unit includes a high-definition LCD screen and waterproof and dustproof buttons for local parameter display and on-site debugging; the communication unit is connected to the Internet of Things remote control device and supports data interaction and command transmission.

[0010] Preferably, the intelligent capacitor bank is composed of multiple independent intelligent capacitor units, supporting independent phase switching; each intelligent capacitor unit includes a switching unit, a control unit, and a self-healing thin-film capacitor body. The switching unit adopts a composite switching structure of thyristors and magnetic latching relays in parallel to achieve zero-crossing switching, and the inrush current is no more than twice the rated current; the control unit is electrically connected to the intelligent voltage regulator controller and receives switching commands to control the switching timing; the self-healing thin-film capacitor body has the ability to self-heal overvoltage faults.

[0011] Preferably, the three-level temperature control architecture of the environmental control unit is as follows: Level 1 Conventional Heat Dissipation: When the temperature inside the cabinet is between 40℃ and 50℃, the silent speed-regulating axial fan of the heat dissipation module is activated for air cooling. Two-stage forced cooling: When the temperature inside the cabinet exceeds 50℃, the semiconductor cooling unit of the heat dissipation module and the intelligent cooling module are activated simultaneously for powerful cooling. Level 3 Low Temperature Antifreeze: When the temperature inside the cabinet is below 5℃, or when the temperature and humidity data show that the ambient temperature is close to the dew point and there is a risk of condensation, the PTC constant temperature heating unit of the auxiliary heater will be activated to heat up and dehumidify. The temperature and humidity control module uses a high-precision four-wire digital temperature and humidity sensor to collect temperature and humidity data of the cabinet environment and core components in real time and upload them to the intelligent voltage regulator.

[0012] Preferably, the protection system of the security protection unit is as follows: Level 1 lightning surge protection: The lightning surge protection module is connected in parallel between the phase line and the neutral line, and between the phase line and the protective ground line at the incoming end of the device. A large-current surge protector with a nominal discharge current of not less than 35kA is used to discharge lightning and power grid operation surges. Secondary electrical circuit protection: The electrical protection module is connected to the main incoming line, the voltage regulating transformer circuit, and the intelligent capacitor bank circuit respectively, and integrates overvoltage, undervoltage, overcurrent, short circuit, phase loss, overload, and overtemperature protection functions, with a fault response time of no more than 10ms; Three-level module-level self-protection: The voltage regulating transformer module, intelligent capacitor unit, and intelligent voltage regulating controller are each equipped with an independent protection sub-unit, which can quickly isolate the fault in the event of a single module failure and prevent the fault from spreading; Level 4 physical protection: The physical protection module adopts dustproof sealing strips, waterproof inlet glands, and line protection sleeve structure, and the overall protection level of the cabinet is not lower than IP54.

[0013] Preferably, the power electronic switch of the seamless bypass unit is an IGBT device, and the mechanical switch is a magnetically latched AC contactor; during normal operation, the mechanical switch carries the load current, and when a fault is triggered, the power electronic switch quickly turns on within 5ms to achieve seamless switching, after which the mechanical switch closes to carry the current; the bypass switching supports automatic triggering of protection linkage, local manual triggering and remote control triggering.

[0014] Preferably, the IoT remote control device adopts a dual-mode architecture of 5G wide-area communication + Bluetooth local communication, and is compatible with MQTT and Modbus industrial communication protocols. It can upload device operating parameters, fault information, voltage regulation compensation data, temperature and humidity data to the background operation and maintenance platform and mobile terminal in real time, and supports remote start and stop, parameter setting, mode switching and fault reset. The built-in fault early warning algorithm can identify potential equipment hazards based on historical operating data and actively push alarms.

[0015] Preferably, the progressive anti-oscillation mechanism included in the multi-level anti-oscillation logic module is as follows: a. Voltage action dead zone: a 2% action dead zone of the rated voltage is set, and no new adjustment action is triggered when the voltage is in the dead zone; b. Two-level delay control: Set a 2-second over-limit judgment delay to filter out instantaneous disturbances, and set a 3-second action interval delay to control the frequency adjustment; c. Cross-equipment operation interlock: During capacitor switching operation, the voltage regulation command is blocked; during voltage regulation gear switching, the capacitor switching command is blocked; only one type of equipment is allowed to operate at the same time. d. Malignant Oscillation Lockout: If the cumulative adjustment action is ≥5 times within 30 seconds, it is judged as a malignant oscillation. All automatic adjustment functions will be forcibly locked and an alarm will be reported. Manual reset is required to restore the function.

[0016] Preferably, the collaborative governance control method of the device includes the following steps: S1. Data Acquisition and Preprocessing: The current and voltage sampling module collects the three-phase electrical parameters of the transformer area at a fixed period. After digital filtering, the average three-phase voltage and reactive power parameters are calculated. Temperature and humidity data and equipment operating status are collected simultaneously in the cabinet. S2. Over-limit validity judgment: The collected voltage is compared with the qualified voltage range. If the voltage exceeds the limit, the over-limit judgment timer is started. If the over-limit continues for a set delay, it is judged as a steady-state voltage abnormality and the adjustment process is entered. If the over-limit is instantaneous, it is judged as a disturbance and the timer is reset and does not operate. S3, Layered Coordinated Voltage Regulation Control: S3.1 Low-voltage operation: When the voltage is lower than the lower limit of the qualified range, the reactive power boost is performed first: the intelligent capacitors are put into operation one group at a time, and the voltage is re-tested after a set interval after each group is put into operation; if the voltage is still lower than the qualified range after all the capacitors are put into operation, the voltage regulating transformer is started to boost the voltage step by step until the voltage returns to the qualified range or reaches the upper limit of the boost level. S3.2 Overvoltage condition: When the voltage is higher than the upper limit of the qualified range, reactive power reduction is performed first: the intelligent capacitors are disconnected one by one, and the voltage is re-detected after a set time interval after each group is disconnected; if the voltage is still higher than the qualified range after all capacitors are disconnected, the voltage regulating transformer is started to reduce the voltage step by step until the voltage returns to the qualified range or reaches the upper limit of the voltage reduction step. S4. Anti-oscillation closed-loop control: During the adjustment process, dead zone judgment, interval delay control and cross-device interlocking are executed synchronously. After the voltage enters the dead zone, the adjustment is stopped immediately and the current state is maintained. S5. Handling of malignant oscillations: Real-time statistics of the number of adjustment actions per unit time. If the oscillation judgment threshold is reached, the automatic adjustment function is locked, local and remote alarms are triggered, and manual reset is required. S6. Steady-state operation: After the voltage stabilizes within the qualified range, reset all timers and action flags, and the device maintains the current state for continuous monitoring.

[0017] Preferably, in step S2, the qualified voltage range is -10% to +15% of the rated voltage; the over-limit determination delay is 2 seconds.

[0018] Preferably, in step S3, the action interval delay after each group of capacitors is switched on and off and each voltage regulation is switched is 3 seconds.

[0019] The beneficial effects of this invention are as follows: by integrating reactive power compensation, precise voltage regulation, intelligent temperature control, dehumidification and antifreeze, multi-level protection, local human-machine interaction, and remote management, it takes into account voltage deviation correction, reactive power loss reduction, and equipment safety protection, and solves problems such as unstable voltage at the end of the distribution transformer area, low power factor, large line loss, and easy equipment damage, thereby improving power supply quality and distribution transformer area operation efficiency.

[0020] It adopts a graded temperature control design that links the temperature and humidity control module with the heat dissipation module, the intelligent cooling module, and the auxiliary heater. It takes into account both high-temperature heat dissipation and low-temperature heating, which can not only prevent outdoor cabinet overheating failure, but also prevent low-temperature condensation, icing, and component freezing damage. It is suitable for various harsh working conditions such as high temperature, high cold, and high humidity, and improves operational reliability.

[0021] It integrates a multi-level protection system for lightning surge protection, electrical protection, physical protection, and low-temperature antifreeze, achieving electrical safety, physical protection, and low-temperature protection. It is suitable for harsh working conditions such as outdoor humidity, frequent lightning, high altitude, large temperature difference, and large load fluctuation, avoiding equipment damage caused by surge breakdown, moisture short circuit, low-temperature freezing damage, external interference, and electrical faults, and significantly extending the service life of the equipment.

[0022] The intelligent voltage regulator module integrates multiple functions such as voltage regulation, bypass, protection, display, buttons, and communication. It supports local on-site debugging and remote control without the need for additional auxiliary equipment. It takes into account both on-site operation and maintenance and remote management, greatly reducing the difficulty of operation and maintenance and labor costs.

[0023] Employing intelligent surge-free switching technology and a high-efficiency voltage regulation topology, capacitor switching is shock-free and has a fast response speed. The voltage regulation process is smooth and lossless. Compared with traditional treatment devices, the overall operating loss is low and the line loss in the transformer area is significantly reduced. It can treat both active and reactive voltage deviation problems, resulting in outstanding energy-saving and efficiency-enhancing effects.

[0024] Adopting a modular integrated design, it is compact in size and easy to install. It can be adapted to various urban and rural low-voltage distribution substations. Whether it is the renovation of old substations or the supporting facilities for new substations, it can be deployed quickly and has strong versatility. Attached Figure Description

[0025] Figure 1 This is a block diagram of the overall system architecture of the present invention; Figure 2 This is a front view of the cabinet of the device of the present invention; Figure 3 This is a right view of the cabinet of the device of the present invention; Figure 4 This is a left view of the cabinet of the device of the present invention; Figure 5 This is a bottom view of the cabinet of the device of the present invention; Figure 6 This is a rendering of the device described in an embodiment of the present invention; Figure 7 This is a physical assembly diagram of the device described in an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0027] Embodiments of the present invention: like Figures 1-6As shown, this invention provides a high-efficiency intelligent hybrid distribution terminal voltage management device. The rated voltage is 380V three-phase four-wire, the rated compensation capacity is 60-120kvar, the voltage regulation range is ±20%Un, and it is suitable for distribution substations with a capacity of 200-400kVA. It adopts an outdoor cabinet-type integrated structure and can be installed on a pole or floor. The device internally includes: a current and voltage sampling module, an intelligent voltage regulator controller module, a voltage regulator transformer module, an intelligent capacitor bank, an environmental control unit (temperature and humidity control module, heat dissipation module, intelligent cooling module, auxiliary heater), a four-level safety protection unit (lightning surge protection module, electrical protection module, module-level protection subunit, physical protection module), a seamless bypass unit, and an IoT remote control device.

[0028] The specific implementation is as follows: Current and voltage sampling module: Employing 0.2-class high-precision LMK series low-voltage current transformers and JDG series voltage transformers, the input terminals are connected to the A, B, and C phases and the neutral line of the low-voltage outgoing line in the transformer substation, while the output terminals are connected to the AD sampling port of the intelligent voltage regulator controller 2. The sampling period is 20ms, and it can collect raw data such as three-phase voltage, three-phase current, and phase angle. The controller then calculates parameters such as power factor, active power, reactive power, and three-phase imbalance, with a sampling error ≤ ±0.2%.

[0029] The input terminal of the current and voltage sampling module is connected to the low-voltage outgoing line at the end of the distribution transformer area, and the output terminal is electrically connected to the signal input terminal of the intelligent voltage regulator module. The module uses low-voltage current transformers and voltage transformers with an accuracy of no less than 0.2 class, and can collect electrical parameters such as three-phase voltage, three-phase current, power factor, active power, reactive power, and three-phase imbalance in real time, with a sampling period of no more than 20ms, providing real-time data support for voltage regulation, reactive power compensation, and fault protection. The intelligent voltage regulator is the core control hub of the entire device, using a 32-bit high-performance industrial-grade main control chip based on the ARM Cortex-M4 core, with a working frequency of 168MHz. The circuit board is coated with conformal coating, suitable for wide-temperature industrial environments. The controller is electrically connected to the current and voltage sampling module, the voltage regulator transformer module, the intelligent capacitor bank, the environmental control unit, the safety protection unit, the seamless bypass unit, and the IoT remote control device.

[0030] The controller integrates the following functional units: Data Acquisition and Processing Unit: Contains a built-in 12-bit high-precision AD converter to perform analog-to-digital conversion on the analog signals transmitted from the sampling module. It uses digital filtering algorithms to remove interference signals and outputs accurate electrical operating and environmental parameters. Voltage Regulation Control Unit: Outputs multiple relay control signals, connecting to the on-load tap changer of the voltage regulating transformer module to control the motor's forward and reverse rotation, thus achieving tap changer up and down operation. It also receives position feedback signals from the tap changer to ensure accurate voltage regulation. Bypass Control Unit: Electrically connected to the drive circuit of the seamless bypass unit, it outputs switch control signals to switch between the main circuit and bypass circuit under fault and maintenance conditions. Protection Logic Unit: Receives fault detection signals from the safety protection unit and executes alarm, trip, and bypass switching actions according to preset protection logic, while recording the fault type. The system includes: a human-machine interface unit (HMI) with a 3.5-inch high-definition LCD screen and six waterproof membrane buttons. The screen displays information such as three-phase voltage, three-phase current, power factor, current compensation capacity, voltage regulation level, cabinet temperature and humidity, and fault codes. The buttons support parameter settings, mode switching, manual voltage regulation, and manual capacitor switching, facilitating on-site maintenance and debugging. The algorithm unit incorporates a layered collaborative control algorithm and multi-level anti-oscillation logic, with "reactive power compensation priority and voltage regulation transformer as a backup" as the core control logic. It coordinates capacitor switching and voltage regulation actions, while suppressing control oscillations through a four-level mechanism of dead zone, delay, interlock, and blocking. The communication unit includes an RS485 local communication interface and a wireless communication interface, supporting Modbus-RTU and MQTT communication protocols, connecting to local debugging equipment and IoT remote control devices respectively.

[0031] Intelligent voltage regulator controller module: Utilizes the HK32F407 industrial-grade main control chip with a 168MHz clock speed, and integrates 512KB Flash and 192KB RAM. The circuit board undergoes conformal coating treatment, and its operating temperature range is -40℃ to +85℃. The controller integrates 7 functional units, features a 3.5-inch TFT LCD display and 6 waterproof membrane buttons, and includes both RS485 and wireless communication interfaces. It also incorporates a hierarchical collaborative control algorithm and anti-oscillation logic.

[0032] Module 3: A three-phase column-type on-load autotransformer with a rated capacity of 200kVA, a rated voltage of 380V, a voltage regulation range of -20% to +20%Un, and 9 tap positions, each adjusting the voltage by 5%. It is equipped with a vacuum on-load tap changer with a mechanical life of 100,000 cycles and a voltage regulation response time of ≤100ms. The transformer windings are equipped with PT100 temperature sensors connected to a temperature and humidity control module, with a winding over-temperature protection threshold of 105℃. The transformer is fixedly installed at the bottom of the cabinet using brackets, and vibration damping pads are added to reduce operating noise.

[0033] Intelligent Capacitor Bank: A total of 6 intelligent capacitor units are configured, 2 units each for phases A, B, and C, with a single unit capacity of 25kvar and a total capacity of 150kvar. Phase-by-phase switching is supported. Each unit uses a thyristor + magnetic latching relay composite switch, enabling zero-crossing switching with inrush current ≤ 2 times the rated current. The capacitor body uses self-healing polypropylene film capacitors with a rated voltage of 450V and a built-in discharge resistor; the voltage at the downstream end is ≤ 50V after 1 minute of power failure. Each unit has its own control board, communicating with the intelligent voltage regulator 2 via RS485 to receive switching commands and providing overvoltage, overtemperature, and phase loss self-protection functions.

[0034] Specifically, a three-phase column-type on-load autotransformer is used, with rated capacity matching the transformer substation capacity. The voltage regulation range is -20% to +20% of the rated voltage, and it has no fewer than 9 tap positions, each with a voltage regulation range of 5%. The on-load tap changer adopts a vacuum arc-extinguishing structure with a mechanical life of no less than 100,000 cycles and a voltage regulation response time of no more than 100ms. The voltage regulation process is free from power outages and significant voltage surges. The transformer body is equipped with a PT100 temperature sensor connected to a temperature and humidity control module to monitor the winding temperature in real time and trigger protection when the temperature exceeds the limit. The intelligent capacitor bank consists of multiple independent intelligent capacitor units, supporting independent phase switching and simultaneously addressing three-phase voltage imbalances. Each intelligent capacitor unit includes a switching unit, a control unit, and a self-healing thin-film capacitor body: The switching unit employs a composite switch structure with a thyristor and a magnetic latching relay connected in parallel. When switched on, the thyristor conducts at the voltage zero-crossing point, then the magnetic latching relay is engaged to handle the load current. When switched off, the magnetic latching relay is disconnected first, then the thyristor turns off at the current zero-crossing point, achieving true zero-crossing switching. The inrush current is less than twice the rated current, with no operational overvoltage and no impact on the power grid. The control unit, based on a 32-bit microcontroller, communicates with the intelligent voltage regulator controller. After receiving switching commands, it precisely controls the switching sequence and simultaneously collects the capacitor's operating voltage, current, and temperature, providing overvoltage, overtemperature, and phase loss self-protection functions. The self-healing thin-film capacitor body uses a metallized polypropylene film dielectric with self-healing properties. When a local breakdown occurs internally, the metallized layer around the breakdown point evaporates under the action of an electric arc, forming an insulating area, and the capacitor automatically returns to normal operation without requiring shutdown or replacement. A built-in discharge resistor reduces the terminal voltage below the safe voltage within one minute after power failure, ensuring operational safety. Environmental Control Unit: Temperature and Humidity Control Module: Employs 4-channel SHT30 digital temperature and humidity sensors, positioned at four monitoring points: the upper part, middle part, near the transformer, and near the capacitor within the cabinet. Temperature measurement accuracy is ±0.3℃, and humidity measurement accuracy is ±2%RH. Real-time data collection from each point is uploaded to the intelligent voltage regulator controller. Heat Dissipation Module: Equipped with two 120mm silent variable-speed axial flow fans, installed at the upper air outlet and lower air inlet of the cabinet, forming an upper and lower convection airflow. The fans support 0-100% PWM speed regulation, with a maximum airflow of 120CFM. Intelligent Cooling Module: Utilizes a semiconductor cooling chip combined with a heat dissipation airflow structure, installed in the middle of the cabinet. Activates above 50℃, rapidly reducing the temperature in the core area of ​​the cabinet. Auxiliary Heater: Employs a PTC ceramic constant-temperature heating element, installed at the lower part of the cabinet. Activates below 5℃ or when there is a risk of condensation. Provides uniform heating without open flame and includes overheat protection. The environmental control unit is centered on a temperature and humidity control module and is electrically connected to a heat dissipation module, an intelligent cooling module, and an auxiliary heater to form a three-level temperature control architecture. It also has high-temperature graded heat dissipation and low-temperature antifreeze and dehumidification functions, achieving wide environmental temperature adaptability from -40℃ to +70℃.

[0035] Temperature and humidity control module: Employs SHT30 high-precision digital temperature and humidity sensors, with four monitoring points located at the top, middle, near the transformer, and near the capacitor within the cabinet. Temperature measurement accuracy is ±0.3℃, and humidity measurement accuracy is ±2%RH. Real-time data collection from each point is uploaded to the intelligent voltage regulator controller. It also supports dew point temperature calculation to predict condensation risk. Cooling module: Equipped with two silent, speed-adjustable axial flow fans, installed at the top air outlet and bottom air inlet of the cabinet respectively, forming an upper and lower convection airflow. The fans support 0-100% speed adjustment, automatically adjusting speed according to temperature to reduce operating noise and energy consumption, meeting the cooling requirements of normal operating conditions. Intelligent cooling module: Utilizes a semiconductor cooling chip combined with a cooling duct structure, installed in the middle of the cabinet. Its cooling capacity matches the cabinet volume. It activates when the internal temperature exceeds 50℃ and conventional air cooling cannot meet temperature control requirements, rapidly reducing the temperature in the core area of ​​the cabinet to cope with high-temperature, heavy-load operating conditions in summer. Auxiliary heater: It adopts PTC ceramic constant temperature heating element, with power matching the cabinet volume, and is installed at the bottom of the cabinet. It provides uniform heating without open flame and has no safety hazards. When the temperature inside the cabinet is lower than 5℃, or the difference between the dew point temperature and the ambient temperature is less than 3℃, and there is a risk of condensation, it will automatically start to raise the temperature inside the cabinet, eliminate the risk of condensation, and prevent low-temperature freezing damage and moisture short circuit.

[0036] The specific method of three-level temperature control is as follows: Level 1: Conventional heat dissipation: When the internal temperature of the cabinet is 40℃ < ≤ 50℃, the axial flow fan of the heat dissipation module is started, and the fan speed is linearly adjusted according to the temperature; Level 2: Forced cooling: When the internal temperature of the cabinet is > 50℃, the heat dissipation module and the intelligent cooling module are started simultaneously for full-speed heat dissipation and cooling; when the temperature drops below 40℃, the intelligent cooling module stops, and the heat dissipation module runs at a low speed; Level 3: Low temperature antifreeze: When the internal temperature of the cabinet is ≤ 5℃, or there is a risk of condensation, the auxiliary heater is started to heat up and dehumidify; after the temperature rises above 10℃ and the risk of condensation is eliminated, the heater automatically stops.

[0037] Level 4 security protection unit: Level 1 Surge Protection: The incoming line is equipped with a 4P large-current surge protector with a nominal discharge current of 40kA (8 / 20μs), a maximum discharge current of 80kA, and a response time of ≤25ns. It is connected in parallel to the phase line-N and phase line-PE. The lightning surge protection module adopts a three-phase four-wire large-current surge protector, which is installed in parallel between the phase line-neutral line and the phase line-protected ground line at the incoming line of the device. The nominal discharge current is not less than 35kA, the maximum discharge current is 80kA, and the response time is less than 25ns. It can quickly discharge lightning-induced surges and grid operation overvoltages, limit the residual voltage within a safe range, prevent surge impacts from damaging internal precision components, improve the equipment's lightning protection and anti-interference capabilities, and is suitable for operation in areas with frequent lightning strikes. Secondary electrical protection: The main incoming line is equipped with a 250A molded case circuit breaker with overload and short-circuit protection; a comprehensive protection relay is configured to provide overvoltage, undervoltage, phase loss, and overcurrent protection; dedicated circuit breakers and fuses are configured for the voltage regulating circuit and capacitor circuit respectively; the electrical protection module is equipped with a molded case circuit breaker and a comprehensive protection relay on the main incoming line, providing overcurrent, short-circuit, phase loss, undervoltage, and overvoltage protection functions; dedicated circuit breakers and fuses are configured for the voltage regulating transformer circuit and the intelligent capacitor bank circuit respectively, achieving independent electrical protection for each circuit; the fault response time is no more than 10ms, and it acts quickly after a fault occurs, cooperating with the protection logic unit to achieve tripping or bypass switching. Tertiary module self-protection: The transformer, capacitor unit, and controller are each equipped with independent temperature, voltage, and current protection, and automatically disconnect the circuit in case of a fault; the voltage regulating transformer module, intelligent capacitor unit, and intelligent voltage regulating controller are each equipped with independent over-temperature, overvoltage, and overcurrent protection sub-units, which can quickly disconnect their own circuits when a single module fails, achieving fault isolation without affecting the operation of other modules and the overall system, and avoiding the spread and expansion of fault losses. Level 4 Physical Protection: The cabinet is welded from 1.5mm cold-rolled steel plate with outdoor electrostatic powder coating for corrosion protection; the cabinet door is equipped with EPDM sealing strips, the inlet hole is equipped with a waterproof gland, and the wiring is run through flame-retardant conduit, with an overall protection level of IP54; the cabinet is welded from cold-rolled steel plate with outdoor powder coating for corrosion protection, the cabinet door is equipped with EPDM rubber sealing strips, the inlet hole is equipped with a waterproof gland, and the wiring is run through waterproof flame-retardant protective conduit, with an overall protection level of IP54, which can effectively block dust intrusion, prevent water splashing, and resist external damage, suitable for outdoor pole-mounted or floor-mounted installation scenarios.

[0038] Seamless Bypass Unit: Employs a 200A SCR device, connected in series between the main circuit and the bypass circuit; configured with a dedicated drive circuit, connected to the bypass control unit of the intelligent voltage regulator controller 2; switching time ≤20ms, supporting automatic, manual, and remote triggering modes. IoT Remote Control Device: Adopts a dual-mode design with a 5G full-network module + Bluetooth 5.0 module, supporting China Mobile, China Unicom, and China Telecom networks; Bluetooth communication distance ≤10m; compatible with MQTT and Modbus-RTU protocols, communicating with the controller via RS485; can be connected to a power distribution maintenance cloud platform, supporting data upload, remote control, fault warning, statistical analysis, and other functions. The seamless bypass unit uses a SCR electronic device, connected in series between the main circuit and the bypass circuit of the device.

[0039] During normal operation, the bypass switch is open, the device is connected to the power distribution circuit, and the load current is output after being treated by the device; when the device experiences a serious fault, needs maintenance, or is taken out of operation, the bypass switch is closed, disconnecting the entire device from the circuit, and the load current is directly supplied to the user through the bypass circuit.

[0040] The switching process employs the control logic of a "power electronic switch": after the switching command is triggered, the thyristor switch quickly turns on within 20ms to handle the load current, achieving seamless power supply switching without voltage drops or power interruptions; subsequently, the magnetically latched AC contactor engages to handle the continuous load current, reducing conduction losses. Bypass switching supports three triggering methods: automatic triggering via protection linkage, local manual button triggering, and remote control triggering, fully adapting to different operation and maintenance scenarios.

[0041] The working process of the device in this embodiment is as follows: After the device is powered on and started, the system performs self-check, initializes each module, and enters the automatic operation mode by default. The current and voltage sampling module 1 continuously collects electrical data of the transformer district with a 20ms cycle, and the intelligent voltage regulation controller calculates three-phase average voltage and reactive power parameters in real time, and compares them with the qualified voltage range (phase voltage 204.6V~235.4V, three-line voltage 353.4V~406.6V). If the voltage exceeds the limit instantaneously and the duration is less than 2s, it is determined as load disturbance and no regulation is triggered; if the continuous over-limit reaches 2s, it is determined as steady-state abnormality, and the hierarchical regulation process is entered. Low-voltage working condition: preferentially put capacitors into operation group by group, and detect the voltage at an interval of 3S after each group is put into operation; if the low voltage is caused by reactive power, preferentially put 6 groups of intelligent capacitor units into operation to offset reactive power loss, if it is caused by active power, raise the voltage regulating transformer step by step, with an interval of 3S between each step, until the voltage is qualified or reaches the highest step. Overvoltage working condition: preferentially cut off capacitors group by group, and detect the voltage at an interval of 3S after each group is cut off; if the voltage is still high after all 9 groups of capacitors are cut off, lower the voltage regulating transformer step by step, with an interval of 3S between each step, until the voltage is qualified or drops to the lowest step. During the regulation process, when the voltage enters the qualified voltage range (phase voltage 204.6V~235.4V, three-phase voltage 353.4V~406.6V), the regulation is stopped immediately and the current state is maintained. Capacitor switching and voltage regulation actions are interlocked, and only one type of equipment operates at the same time. A mandatory interval of 3S is set between every two actions to avoid continuous regulation. The system counts the number of actions within 30s in real time. If the cumulative number reaches 5 times, it is determined as malignant oscillation, the automatic regulation is immediately locked, local and remote alarms are triggered, and manual reset is waited for.

[0042] During operation, the temperature and humidity control module monitors the temperature and humidity inside the cabinet in real time, and automatically starts heat dissipation, cooling or heating according to the three-level temperature control logic to maintain the temperature and humidity inside the cabinet within a safe range. The four-level safety protection unit monitors various faults throughout the whole process. When a fault occurs, it performs alarm, tripping or bypass switching according to the protection level to ensure the safety of equipment and power grid. The Internet of Things remote control device synchronously uploads all operation data to the cloud platform. Operation and maintenance personnel can view the equipment status in real time through computers or mobile phone APPs, adjust parameters and control equipment remotely; the system automatically analyzes the operation trend, pushes early warning information in advance when hidden dangers are found, and guides active operation and maintenance. When a serious fault occurs to the device or maintenance is required, the seamless bypass unit quickly switches to the bypass mode, the power supply of the transformer district is not affected, and operation and maintenance personnel can safely shut down the device for maintenance.

[0043] As an implementable mode, the voltage hierarchical cooperative management and control method matched with the device specifically includes the following steps: S1, Data collection and preprocessing: The current and voltage sampling module collects raw three-phase voltage and current data of the distribution area at a period of 20ms. After digital filtering to remove pulse interference, it calculates parameters such as three-phase average voltage, active power, reactive power, power factor, and three-phase imbalance. The temperature and humidity sensor collects temperature and humidity data of each monitoring point in the cabinet at the same time and calculates dew point temperature and condensation risk. At the same time, it reads the current capacitor switching status, voltage regulation level, equipment fault status and other operating information.

[0044] S2. Validity determination for exceeding limits: The acceptable voltage range is -10% to +15% of the rated voltage. Compare the calculated three-phase average voltage with the acceptable range: If the voltage is within the acceptable range: it is determined to be normal operation, all over-limit timers and action flags are reset, and the process returns to step S1 for continuous monitoring; If the voltage exceeds the acceptable range: start a 2-second over-limit judgment timer; if the voltage returns to the acceptable range during the timing process, it is judged as an instantaneous load disturbance, the timer is reset to zero, and no regulation is triggered; if the over-limit time continues for 2 seconds, it is judged as a steady-state voltage abnormality, and the tiered regulation process is initiated.

[0045] S3, Layered Coordinated Voltage Regulation Control: Depending on the direction of voltage over-limit, the low-voltage boost and over-voltage de-limit processes are executed respectively, always adhering to the control principle of "parallel coordination of reactive power compensation and voltage regulating transformer".

[0046] S3.1 Low-voltage boost operation (average voltage < lower acceptable limit) Prioritize reactive power boosting: Check the activation status of the intelligent capacitor bank. If not all of them are activated and the interval since the last adjustment has reached 3 seconds, activate the capacitors one by one to reduce the line voltage drop and boost the terminal voltage using reactive power compensation. After activating each capacitor bank, re-detect the voltage. If the voltage returns to the qualified range, stop the activation. If the voltage is still below the qualified range after activation but meets the interval delay requirement, continue to activate the next bank.

[0047] Voltage regulation with backup boost: If the voltage is still below the acceptable range after all the smart capacitor banks are engaged, the capacitor switching action is locked, and the voltage regulating transformer boost process is initiated; the voltage regulation level is checked, and if the highest boost level has not been reached and 3 seconds have passed since the last voltage regulation interval, the voltage regulating transformer is controlled to increase one level; after each level increase, the voltage is rechecked, and if the voltage returns to the acceptable range, voltage regulation is stopped; if it is still below the acceptable range, the level increase continues until the voltage is acceptable or the highest boost level is reached.

[0048] S3.2 Overvoltage drop condition (average voltage > upper limit of acceptable voltage) Prioritize reactive power reduction: Check the status of the intelligent capacitor bank. If not all of them are disconnected and the interval since the last adjustment has reached 3 seconds, disconnect the capacitors one by one to reduce reactive power injection and lower the terminal voltage. After disconnecting each group, retest the voltage. If the voltage returns to the qualified range, stop disconnecting. If the voltage is still higher than the qualified range after disconnection and meets the interval delay requirement, continue disconnecting the next group.

[0049] Voltage regulation with backup voltage reduction: If the voltage is still higher than the acceptable range after all intelligent capacitor banks are disconnected, the capacitor switching action is locked, and the voltage regulation transformer voltage reduction process is started; the voltage regulation level is checked. If the lowest voltage reduction level has not been reached and 3 seconds have passed since the last voltage regulation interval, the voltage regulation transformer is controlled to reduce one level; the voltage is re-checked after each reduction. If the voltage returns to the acceptable range, the voltage regulation stops; if it is still higher than the acceptable range, the voltage reduction continues until the voltage is acceptable or the lowest voltage reduction level is reached.

[0050] S4. Anti-oscillation closed-loop control: During the adjustment process, a four-level anti-oscillation mechanism is implemented simultaneously to suppress and control oscillations: Voltage dead zone control: Set an operating dead zone of 2% of the rated voltage. The dead zone on the low voltage side is [lower acceptable limit - 2%Un, lower acceptable limit], and the dead zone on the high voltage side is [upper acceptable limit, upper acceptable limit + 2%Un]. When the adjusted voltage enters the dead zone, immediately stop all adjustment actions, maintain the current equipment state, and avoid frequent operation caused by the voltage crossing back and forth near the threshold.

[0051] Action interval delay: After each capacitor switching or voltage regulation gear switching is completed, a 3-second interval timer is forcibly started. During the timer, all similar regulation actions are blocked, giving the grid voltage sufficient response stabilization time and avoiding overshoot oscillation caused by continuous rapid regulation.

[0052] Cross-device operation interlock: During the execution of capacitor switching, all voltage regulation commands are blocked; during the execution of voltage regulation level switching, all capacitor switching commands are blocked; only one type of regulating device is allowed to operate at the same time to avoid the superposition of two types of regulation quantities, which would cause drastic voltage fluctuations and trigger secondary oscillations.

[0053] State maintenance logic: When the voltage is in the qualified range or dead range, the equipment maintains the current switching state and voltage regulation level, does not perform any adjustment action, and maintains steady-state operation.

[0054] S5. Handling of malignant oscillations: Real-time statistics of the cumulative number of capacitor switching and voltage regulation actions within a 30-second time window: If the cumulative number of actions is less than 5: it is considered normal adjustment and will be continuously counted. If the cumulative number of actions is ≥5: it is determined to be a malignant control oscillation, and the following measures should be taken immediately: Forcefully lock all automatic adjustment functions, locking the device in the current operating state and no longer executing any automatic adjustment commands; The controller locally triggers an oscillation fault code and activates an audible and visual alarm. The IoT remote control device pushes oscillation alarm information to the back-end and operation and maintenance terminal, along with historical action records and voltage curves. After maintenance personnel investigate the cause and resolve the fault on-site, the automatic adjustment function can be restored through local or remote manual reset.

[0055] S6. Steady-state operation: When the voltage stabilizes within the acceptable range and there are no faults or alarms, the device enters a steady-state operation, resets all timers, counters and action flags, continuously monitors electrical and environmental parameters in real time, and repeats the above process in a loop.

[0056] It should be noted that, depending on the implementation needs, the various components described in the embodiments of the present invention can be divided into more components, or two or more components or parts of components can be combined into new components to achieve the purpose of the embodiments of the present invention. The above embodiments only illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A high-efficiency intelligent hybrid distribution terminal voltage management device, characterized in that, This includes a current and voltage sampling module for connecting to the end line of the distribution substation, an intelligent voltage regulator module, a voltage regulating transformer module, and an intelligent capacitor bank; It also includes an environmental control unit, a safety protection unit, a seamless bypass unit, and an Internet of Things remote control device; The voltage regulator module incorporates a hierarchical collaborative control algorithm module and a multi-level anti-oscillation logic module. The system adopts a dual-dimensional voltage regulation architecture of reactive power compensation and transformer voltage regulation in parallel and collaborative manner to classify and manage high and low voltage problems: based on the cause of voltage drop, fault diversion and independent regulation are achieved; among them, low voltage caused by insufficient reactive power is compensated by intelligent capacitor banks switching reactive power to quickly raise the voltage; high and low voltage caused by lack of active power and low overall grid amplitude is handled by the voltage regulating transformer module to complete amplitude-level voltage regulation as a fallback; the two types of regulation units work in parallel and perform their respective functions to manage reactive power voltage drop and active power voltage drop respectively, realizing refined and differentiated closed-loop management of voltage deviation; The environmental control unit adopts a three-level graded temperature control architecture, with the temperature and humidity control module as the core, linking the heat dissipation module, intelligent cooling module and auxiliary heater, and has the functions of high-temperature graded heat dissipation and low-temperature antifreeze and dehumidification. The safety protection unit includes four levels of protection: surge protection, electrical protection, module protection, and physical protection. The seamless bypass unit adopts a topology structure of parallel power electronic switches and mechanical switches for seamless switching of power supply to the transformer substation under maintenance conditions.

2. The high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The current and voltage sampling module uses current transformers and voltage transformers with an accuracy of no less than 0.2, and a sampling period of no more than 20ms. It can collect three-phase voltage, three-phase current, power factor, active power, reactive power and three-phase unbalance parameters in real time. The output terminal is electrically connected to the signal input terminal of the intelligent voltage regulator.

3. The high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The intelligent voltage regulator controller uses a 32-bit industrial-grade ARM main control chip, which integrates a data acquisition and processing unit, a voltage regulation control unit, a bypass control unit, a protection logic unit, a human-machine interaction unit, an algorithm calculation unit, and a communication unit. The voltage regulation control unit is electrically connected to the actuator of the voltage regulation transformer module and is used to issue voltage regulation level commands; the bypass control unit is electrically connected to the seamless bypass unit and is used to trigger bypass switching actions; the protection logic unit is linked with the safety protection unit and is used for fault determination and protection action triggering; the human-machine interaction unit includes a high-definition LCD screen and waterproof and dustproof buttons for local parameter display and on-site debugging; the communication unit is connected to the Internet of Things remote control device and supports data interaction and command transmission.

4. The high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The intelligent capacitor bank consists of multiple independent intelligent capacitor units, supporting independent phase switching; each intelligent capacitor unit includes a switching unit, a control unit, and a self-healing thin-film capacitor body. The switching unit adopts a composite switching structure of thyristors and magnetic latching relays in parallel to achieve zero-crossing switching, and the inrush current is no more than twice the rated current; the control unit is electrically connected to the intelligent voltage regulator controller and receives switching commands to control the switching timing; the self-healing thin-film capacitor body has the ability to self-heal overvoltage faults.

5. The high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The three-level temperature control architecture of the environmental control unit is as follows: Level 1 Conventional Heat Dissipation: When the temperature inside the cabinet is between 40℃ and 50℃, the silent speed-regulating axial fan of the heat dissipation module is activated for air cooling. Two-stage forced cooling: When the temperature inside the cabinet exceeds 50℃, the semiconductor cooling unit of the heat dissipation module and the intelligent cooling module are activated simultaneously for powerful cooling. Level 3 Low Temperature Antifreeze: When the temperature inside the cabinet is below 5℃, or when the temperature and humidity data show that the ambient temperature is close to the dew point and there is a risk of condensation, the PTC constant temperature heating unit of the auxiliary heater will be activated to heat up and dehumidify. The temperature and humidity control module uses a high-precision four-wire digital temperature and humidity sensor to collect temperature and humidity data of the cabinet environment and core components in real time and upload them to the intelligent voltage regulator.

6. The high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The protection system of the security protection unit is specifically as follows: Level 1 lightning surge protection: The lightning surge protection module is connected in parallel between the phase line and the neutral line, and between the phase line and the protective ground line at the incoming end of the device. A large-current surge protector with a nominal discharge current of not less than 35kA is used to discharge lightning and power grid operation surges. Secondary electrical circuit protection: The electrical protection module is connected to the main incoming line, the voltage regulating transformer circuit, and the intelligent capacitor bank circuit respectively, and integrates overvoltage, undervoltage, overcurrent, short circuit, phase loss, overload, and overtemperature protection functions, with a fault response time of no more than 10ms; Three-level module-level self-protection: The voltage regulating transformer module, intelligent capacitor unit, and intelligent voltage regulating controller are each equipped with an independent protection sub-unit, which can quickly isolate the fault in the event of a single module failure and prevent the fault from spreading; Level 4 physical protection: The physical protection module adopts dustproof sealing strips, waterproof inlet glands, and line protection sleeve structure, and the overall protection level of the cabinet is not lower than IP54.

7. The high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The progressive anti-oscillation mechanism included in the multi-level anti-oscillation logic module is as follows: a. Voltage action dead zone: Set an action dead zone of 2% of the rated voltage. When the voltage is in the dead zone, no new adjustment action is triggered. b. Two-level delay control: Set a 2-second over-limit judgment delay to filter out instantaneous disturbances; set a 3-second action interval delay to control the adjustment frequency; c. Cross-equipment operation interlock: Lock the voltage regulation command during capacitor switching operation; lock the capacitor switching command during voltage regulation level switching; only one type of equipment is allowed to operate at any given time. d. Malignant Oscillation Lockout: If the cumulative adjustment action is ≥5 times within 30 seconds, it is judged as a malignant oscillation, all automatic adjustment functions are forcibly locked and an alarm is reported. Manual reset is required to restore the function.

8. A high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The power electronic switch of the seamless bypass unit is an IGBT device, and the mechanical switch is a magnetically latched AC contactor. During normal operation, the mechanical switch carries the load current. When a fault is triggered, the power electronic switch quickly turns on within 5ms to achieve seamless switching, and then the mechanical switch closes to take over the current. The bypass switching supports automatic triggering of protection linkage, local manual triggering, and remote control triggering.

9. A high-efficiency intelligent hybrid distribution terminal voltage management device according to claim 1, characterized in that, The IoT remote control device adopts a dual-mode architecture of 5G wide-area communication + Bluetooth local communication, and is compatible with MQTT and Modbus industrial communication protocols. It can upload device operating parameters, fault information, voltage regulation compensation data, temperature and humidity data to the background operation and maintenance platform and mobile terminal in real time. It supports remote start and stop, parameter setting, mode switching and fault reset. The built-in fault early warning algorithm can identify potential equipment hazards based on historical operating data and actively push alarms.

Images