Low-voltage power distribution network coordinated voltage regulation autonomous device

Abstract

The application discloses a kind of low voltage distribution network coordinated control voltage autonomous device, comprising: perception, decision-making, hierarchical execution, four-layer architecture of multi-source cooperation, perception layer includes: three-phase voltage acquisition module, three-phase current acquisition module, active power acquisition module, photovoltaic state monitoring module, for collecting power grid parameters and photovoltaic inverter operation data according to minute level interval;Decision-making layer includes: working condition clustering unit, double-target hierarchical determination unit, for executing working condition classification and priority determination;Hierarchical execution layer includes: gear type coarse adjustment unit, fine-tuning unit, strategy iteration unit;Low voltage distribution network coordinated control voltage autonomous device;Multi-source cooperation layer includes: multi-protocol communication module, photovoltaic inverter cooperation module.The application is adapted to rural, urban community and other multiple types of low voltage distribution network scenes containing new energy;It has strong edge autonomous ability simultaneously, without relying on centralized main station can complete acquisition-determination-compensation-iteration whole process.

Description

Technical Field

[0001] This invention relates to the technical field of power quality management in power systems, and more particularly to a low-voltage distribution network collaborative regulation voltage self-governance device. Background Technology

[0002] With the large-scale integration of distributed photovoltaic power, energy storage, electric vehicle charging piles, and high-power single-phase loads into low-voltage distribution networks, the operating characteristics of distribution networks are shifting from the traditional "passive" to "active." Bidirectional voltage over-limit (excessive over / under) and three-phase imbalance problems are becoming increasingly prominent, often exhibiting strong coupling and dynamic interaction, severely impacting power quality, equipment safety, and the efficiency of renewable energy absorption. Low-voltage distribution network collaborative regulation voltage self-regulation device. Existing power quality management solutions have the following shortcomings: Low-voltage distribution network collaborative regulation voltage self-regulation device 1. Ambiguous target priorities: Dynamic weighting or single-target strategies are frequently used, without clearly defining the core logic of voltage priority. This leads to conflicts between voltage exceeding limits and imbalance management, resulting in insufficient power supply stability; low-voltage distribution network collaborative regulation voltage self-regulation devices... 2. Limited adjustment methods: Relying solely on fixed compensation from traditional equipment such as capacitors and reactors, lacking coordination with new energy equipment like photovoltaic inverters, and failing to establish a tiered governance system of coarse and fine adjustments, resulting in insufficient adjustment precision and flexibility; low-voltage distribution network collaborative regulation voltage self-regulation device. 3. Unclear Judgment Logic: The functional positioning of three-phase imbalance and contribution is not clearly distinguished, leading to inaccurate judgment and unclear positioning of imbalance problems, and low governance efficiency; Low-voltage distribution network collaborative regulation voltage self-governance device 4. Lack of application of core formulas: A unified theoretical support for voltage regulation and imbalance mitigation has not been established, compensation calculations lack scientific basis, and precise matching is difficult to achieve. Low-voltage distribution network coordinated control voltage self-regulation device. While some studies have attempted to incorporate multi-objective optimization, they generally suffer from problems such as complex algorithms, poor adaptability to renewable energy equipment like photovoltaics, and weak local autonomy, making it difficult to meet the practical engineering needs of low-voltage distribution networks for voltage priority, precise governance, and renewable energy integration. Therefore, there is an urgent need for a modular voltage autonomy solution that prioritizes voltage, employs a coarse-to-fine adjustment approach, is supported by core formulas, and is supplemented by photovoltaic integration, in order to improve the power supply reliability, operational economy, and renewable energy absorption capacity of low-voltage active distribution networks. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] In view of the problems existing in the above-mentioned low-voltage distribution network collaborative regulation voltage autonomous devices, this invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a low-voltage distribution network collaborative regulation voltage autonomous device that supports collaboration with photovoltaic inverters and smart fusion terminals, and is suitable for various low-voltage distribution network scenarios containing new energy sources, such as rural areas and urban communities; at the same time, it has strong edge autonomy capabilities, and can complete the entire process of data acquisition-judgment-compensation-iteration without relying on a centralized master station, and is suitable for the characteristics of large differences in communication conditions in low-voltage distribution networks.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-voltage distribution network collaborative regulation voltage autonomy device, comprising: A four-layer architecture encompassing perception, decision-making, hierarchical execution, and multi-source collaboration. The sensing layer includes: a three-phase voltage acquisition module, a three-phase current acquisition module, an active power acquisition module, and a photovoltaic status monitoring module, which are used to acquire grid parameters and photovoltaic inverter operating data at minute intervals; The decision-making layer includes: a working condition clustering unit and a dual-objective hierarchical decision-making unit, which are used to perform working condition classification and priority determination; The hierarchical execution layer includes: a level-based coarse adjustment unit, a fine adjustment unit, and a strategy iteration unit; wherein, the level-based coarse adjustment unit is used to perform voltage over-limit coarse adjustment, the fine adjustment unit is used to perform three-phase imbalance management, and the strategy iteration unit is used to adjust the acquisition interval and iteratively correct the strategy according to the abnormal rules; a low-voltage distribution network collaborative regulation voltage autonomous device; The multi-source collaboration layer includes a multi-protocol communication module and a photovoltaic inverter collaboration module, which are used to receive the substation-level collaboration limits of the intelligent converged terminal and to interact with the photovoltaic inverter for reactive power dispatching commands.

[0007] A low-voltage active distribution network collaborative regulation voltage autonomy method, which is executed collaboratively by a voltage autonomy device and a photovoltaic inverter, includes the following steps: S1: Operating Condition Classification and Data Acquisition: The device collects real-time data on three-phase voltage, three-phase current, distribution point switching power P, and photovoltaic inverter operating status of the low-voltage active distribution network. The operating conditions are further subdivided into two dimensions: voltage over-limit status and three-phase unbalance. The three-phase unbalance and its contribution are calculated simultaneously. The degree of voltage over-limit is classified according to the voltage value, and the three-phase unbalance is classified according to the ratio of the negative sequence component to the positive sequence component. S2: Dual-objective hierarchical judgment: Based on the typical operating conditions generated in step S1, a voltage priority fixed priority strategy is adopted: the first priority is the bidirectional voltage over-limit management, and the second priority is the three-phase imbalance management. S3: Tiered compensation implementation; S4: Distribution Area Coordination Threshold Adjustment: Every 30 minutes, the device receives the distribution area-level voltage coordination limit and photovoltaic consumption demand parameters issued by the intelligent fusion terminal via the LORA / HPLC protocol, dynamically updates the local voltage compensation threshold and the reactive power adjustment range of the photovoltaic inverter, and adapts to the needs of large-scale grid optimization and new energy consumption.

[0008] As a preferred embodiment of the low-voltage active distribution network coordinated regulation voltage autonomy method of the present invention, wherein the specific criteria for classifying the degree of voltage exceeding the limit in step S1 are as follows: a. Voltage below the lower limit: The voltage of any one of the three phases is below 198V; Low-voltage distribution network coordinated regulation voltage self-regulation device. b. Voltage generally exceeds the upper limit: the voltage of any one of the three phases is higher than 235V but lower than 253V; low-voltage distribution network coordinated regulation voltage self-regulation device. c. Voltage severely exceeds the upper limit: The voltage of any one of the three phases is higher than 253V.

[0009] As a preferred embodiment of the low-voltage active distribution network coordinated regulation voltage autonomy method of the present invention, wherein: the three-phase imbalance in step S1 is calculated by an empirical formula, the formula being: ; in, This refers to the three-phase current imbalance. , , These correspond to the effective voltage values ​​of phases a, b, and c, respectively.

[0010] As a preferred embodiment of the low-voltage active distribution network coordinated regulation voltage autonomy method of the present invention, wherein: the three-phase imbalance contribution in step S1 is calculated by a formula, the formula being: ; in, Let be the effective value of the i-th phase voltage (i=a,b,c). The average value of the three-phase voltage; the adjustment sequence is from Compensation is applied sequentially from the highest phase to the lowest phase, gradually reducing the phase density. Up to ≤2%.

[0011] As a preferred embodiment of the low-voltage active distribution network coordinated regulation voltage autonomy method of the present invention, step S3 includes: S3.1: Coarse Adjustment for Voltage Exceeding Limits: The device performs coarse adjustment by adjusting capacitor switching or reactor adjustment according to the direction of the voltage exceeding the limit. This allows the voltage to quickly enter the acceptable range of 198V-235V; S3.2 Three-phase imbalance fine-tuning: After the voltage is qualified, if the three-phase imbalance is >2%, the key adjustment phase is located based on the contribution of the three-phase imbalance. The target phase's reactive power deficiency is accurately compensated by fine-tuning the grouped capacitors and coordinating with the reactive power of the photovoltaic inverter. S3.3 Abnormal Iteration: If the following abnormality occurs within the sampling interval: the voltage fluctuation exceeds 5V within 3 consecutive sampling periods, the sampling interval will be adjusted from 15 minutes to 5 minutes, and S3.1-S3.2 will be re-executed based on the new sampling data until the voltage stabilizes between 198V and 235V and the three-phase imbalance is stable at ≤2%.

[0012] As a preferred embodiment of the low-voltage active distribution network coordinated regulation voltage autonomy method described in this invention, the compensation amount is based on the core formula: ; in The reactive power compensated by the device. The reactive power compensated by the photovoltaic inverter, R and X are the line resistance and reactance respectively, and P is the line active power. The specific allocation rules are as follows: a. Voltage over-limit management phase S3.1: Priority allocation Perform a coarse adjustment. Maintain the base compensation amount, i.e., maintain the power factor at 0.95; b. Three-phase imbalance mitigation stage S3.2: Maintain the voltage at the appropriate setting, utilizing the idle group capacitors and photovoltaic inverter within the device. The power factor is dynamically adjusted according to the unbalanced contribution to maintain it within the range of 0.9-1.

[0013] The beneficial effects of this invention are as follows: Compared with the prior art, this invention has significant advantages: its voltage priority clearly defines the governance priority, effectively ensuring power supply safety; through a coarse adjustment + fine adjustment hierarchical strategy and the reuse of existing photovoltaic equipment, governance costs can be reduced by more than 30%; by dividing the work of imbalance determination and contribution positioning, the judgment logic is simplified and manual intervention is reduced; it supports collaboration with photovoltaic inverters and smart integrated terminals, adapting to various low-voltage distribution network scenarios containing new energy sources, such as rural areas and urban communities; at the same time, it has strong edge autonomy capabilities, completing the entire process of data collection-judgment-compensation-iteration without relying on a centralized master station, adapting to the characteristics of large differences in communication conditions in low-voltage distribution networks. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the process structure of the low-voltage distribution network collaborative regulation voltage autonomous device of the present invention.

[0015] Figure 2 This is a schematic diagram of the four-layer architecture of the low-voltage distribution network collaborative regulation voltage autonomous device of the present invention. Detailed Implementation

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0017] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0018] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0019] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0020] Reference Figures 1-2 A low-voltage distribution network collaborative regulation voltage autonomy device is provided, comprising: A four-layer architecture encompassing perception, decision-making, hierarchical execution, and multi-source collaboration. The sensing layer includes: a three-phase voltage acquisition module, a three-phase current acquisition module, an active power acquisition module, and a photovoltaic status monitoring module, which are used to acquire grid parameters and photovoltaic inverter operating data at minute intervals; The decision-making layer includes: a working condition clustering unit and a dual-objective hierarchical decision-making unit, which are used to perform working condition classification and priority determination; The hierarchical execution layer includes: a level-based coarse adjustment unit, a fine-tuning unit, and a strategy iteration unit; wherein, the level-based coarse adjustment unit is used to perform voltage over-limit coarse adjustment, the fine-tuning unit is used to perform three-phase imbalance management, and the strategy iteration unit is used to adjust the acquisition interval and iteratively correct the strategy according to the abnormal rules; low-voltage distribution network collaborative regulation voltage autonomous device. The multi-source collaboration layer includes a multi-protocol communication module and a photovoltaic inverter collaboration module, which are used to receive the substation-level collaboration limits of the intelligent converged terminal and to interact with the photovoltaic inverter for reactive power dispatching commands.

[0021] Specifically, a low-voltage active distribution network collaborative regulation voltage autonomy method, executed collaboratively by a voltage autonomy device and a photovoltaic inverter, includes the following steps: S1: Operating Condition Classification and Data Acquisition: The device collects real-time data on three-phase voltage, three-phase current, distribution point switching power P, and photovoltaic inverter operating status of the low-voltage active distribution network. The operating conditions are further subdivided into two dimensions: voltage over-limit status and three-phase unbalance. The three-phase unbalance and its contribution are calculated simultaneously. The degree of voltage over-limit is classified according to the voltage value, and the three-phase unbalance is classified according to the ratio of the negative sequence component to the positive sequence component. S2: Dual-objective hierarchical judgment: Based on the typical operating conditions generated in step S1, a voltage priority fixed priority strategy is adopted: the first priority is the bidirectional voltage over-limit management, and the second priority is the three-phase imbalance management. S3: Tiered compensation implementation; S4: Distribution Area Coordination Threshold Adjustment: Every 30 minutes, the device receives the distribution area-level voltage coordination limit and photovoltaic consumption demand parameters issued by the intelligent fusion terminal via the LORA / HPLC protocol, dynamically updates the local voltage compensation threshold and the reactive power adjustment range of the photovoltaic inverter, and adapts to the needs of large-scale grid optimization and new energy consumption.

[0022] The specific criteria for classifying the degree of voltage exceeding the limit in step S1 are as follows: a. Voltage below the lower limit: The voltage of any one of the three phases is below 198V; Low-voltage distribution network coordinated regulation voltage self-regulation device. b. Voltage generally exceeds the upper limit: the voltage of any one of the three phases is higher than 235V but lower than 253V; low-voltage distribution network coordinated regulation voltage self-regulation device. c. Voltage severely exceeds the upper limit: The voltage of any one of the three phases is higher than 253V.

[0023] Furthermore, the three-phase imbalance in step S1 is calculated using an empirical formula, which is: ; in, This refers to the three-phase current imbalance. , , These correspond to the effective voltage values ​​of phases a, b, and c, respectively.

[0024] Furthermore, the contribution of the three-phase imbalance in step S1 is calculated using the formula: ; in, Let be the effective value of the i-th phase voltage (i=a,b,c). The average value of the three-phase voltage; the adjustment sequence is from Compensation is applied sequentially from the highest phase to the lowest phase, gradually reducing the phase density. Up to ≤2%.

[0025] Step S3 includes: S3.1: Coarse Adjustment for Voltage Exceeding Limits: The device performs coarse adjustment by adjusting capacitor switching or reactor adjustment according to the direction of the voltage exceeding the limit. This allows the voltage to quickly enter the acceptable range of 198V-235V; S3.2 Three-phase imbalance fine-tuning: After the voltage is qualified, if the three-phase imbalance is >2%, the key adjustment phase is located based on the contribution of the three-phase imbalance. The target phase's reactive power deficiency is accurately compensated by fine-tuning the grouped capacitors and coordinating with the reactive power of the photovoltaic inverter. S3.3 Abnormal Iteration: If the following abnormality occurs within the sampling interval: the voltage fluctuation exceeds 5V within 3 consecutive sampling periods, the sampling interval will be adjusted from 15 minutes to 5 minutes, and S3.1-S3.2 will be re-executed based on the new sampling data until the voltage stabilizes between 198V and 235V and the three-phase imbalance is stable at ≤2%.

[0026] Specifically, the compensation amount is based on the core formula: ; in The reactive power compensated by the device. The reactive power compensated by the photovoltaic inverter, R and X are the line resistance and reactance respectively, and P is the line active power. The specific allocation rules are as follows: a. Voltage over-limit management phase S3.1: Priority allocation Perform a coarse adjustment. Maintain the base compensation amount, i.e., maintain the power factor at 0.95; b. Three-phase imbalance mitigation stage S3.2: Maintain the voltage at the appropriate setting, utilizing the idle group capacitors and photovoltaic inverter within the device. The power factor is dynamically adjusted according to the unbalanced contribution to maintain it within the range of 0.9-1.

[0027] To make the technical solution of this invention clearer and easier to understand, an example is given in a typical rural area with distributed photovoltaic power generation to verify the feasibility and effectiveness of the technical solution.

[0028] 1. Overview of Implementation Scenarios (1) A rural transformer substation has a capacity of 200kVA, a power supply radius of 500m, and uses 120mm² lines. 2 Aluminum core wire, calculated , Therefore The distributed photovoltaic installation capacity is 150kW, the inverter power factor is adjustable from 0.9 to 1.0, and the maximum reactive power output is 50kvar. Before the upgrade, the voltage fluctuation range in the pre-installed area is 195V-245V, and the three-phase imbalance is 3.5%, resulting in frequent voltage exceedances and imbalances.

[0029] 2. Device Hardware Configuration and Parameter Setting: Low-voltage distribution network coordinated regulation voltage autonomous device (1) Hardware configuration of modular voltage autonomous device: Low-voltage distribution network coordinated regulation voltage autonomous device Gradient-type coarse adjustment unit: 1 x 50kvar magnetically controlled reactor (rated voltage 230V, firing angle adjustment range 0°-180°), 60kvar capacitor bank (divided into 3 levels, 20kvar per level, switching response time ≤1s); Low-voltage distribution network coordinated regulation voltage self-regulation device. Fine-tuning unit: 30kvar grouped capacitors (divided into 3 groups, 10kvar each, supporting independent switching of A / B / C phases), photovoltaic inverter collaborative interface (supporting Modbus-RTU protocol); low-voltage distribution network collaborative regulation voltage autonomous device. Controller: Employs an ARM Cortex-M7 processor (400MHz), equipped with a 480×240 resolution LCD screen and 4 operation buttons, supporting local parameter setting and operation status viewing; Low-voltage distribution network coordinated regulation voltage autonomous device. Sensing module: Voltage / current sampling accuracy class 0.2, active power calculation error ≤0.5%, sampling frequency 50Hz. 2. Operating condition clustering and parameter calculation. (2) Core parameter settings: Low-voltage distribution network coordinated regulation voltage autonomous device Voltage acceptable range: 198V-235V; Low-voltage distribution network coordinated regulation voltage self-regulation device Three-phase imbalance qualification standard: ≤2%; Low-voltage distribution network coordinated regulation voltage self-regulation device. The basic power factor of the photovoltaic inverter is 0.95 (when there is no imbalance control requirement).

[0030] 3. Hierarchical control process and effects: Low-voltage distribution network coordinated control voltage autonomous device (1) Working condition data acquisition and determination (S1-S2): Data collected by the device: Phase A voltage 240V, generally exceeding the voltage limit; Phase B voltage 233V; Phase C voltage 232V. During peak daytime solar power generation, the transformer output power is approximately equal to the solar power output. The current active power output of the solar inverter is 120kW. Three-phase imbalance: ; Phase A has the highest contribution from phase imbalance: ; The decision-making level determines that the current operating condition is voltage over-limit + imbalance, and executes the first priority voltage over-limit management, generating a coarse voltage adjustment command. Low-voltage distribution network coordinated control voltage self-regulation device. (2) Coarse adjustment of voltage over-limit (S3.1) According to the core formula Calculate the total compensation requirement: .

[0031] Device control command: Activate the 50kvar magnetically controlled reactor, then maintain the photovoltaic inverter with a power factor above 0.95, which will enable power generation. The reactive power is such that the photovoltaic inverter can generate 30kVar at this time.

[0032] Coarse adjustment result: After one sampling cycle, the voltage of phase A drops to 230V, phase B to 225V, and phase C to 223V, with the voltage stabilizing within the acceptable range of 198V-235V.

[0033] (3) Three-phase imbalance fine adjustment (S3.2) Low-voltage distribution network coordinated regulation voltage autonomous device After the voltage was found to be within acceptable limits, the three-phase imbalance was detected. Phase A contributes the most, generating a fine-tuning command. The power factor of phase A in the single-phase photovoltaic inverter is reduced by an order of 0.1, but not lower than 0.9. Then, the power factors of phases B and C are adjusted to increase until... The voltage should be maintained within the acceptable range of 225V-230V. 4. Abnormal Iteration and Transformer Area Collaboration (S3.3-S4) After running for 2 hours, the photovoltaic power generation in the distribution area reached full capacity. If the voltage fluctuation exceeds 6V (exceeding the 5V threshold) for three consecutive sampling cycles, the device will automatically adjust the sampling interval to 3 minutes. Recalculate the total compensation: By installing a 50kvar magnetically controlled reactor and maintaining a power factor of 0.95 in the photovoltaic inverter, it can generate electricity. The reactive power was 88.4 kVar, and then fine-tuned, the voltage fluctuation was reduced to 3V and returned to stability.

[0034] Area-level collaborative threshold adjustment: Every 30 minutes, the device receives the area-level voltage collaborative limit value issued by the intelligent fusion terminal via the LORA / HPLC protocol, and dynamically updates the local voltage compensation threshold. For example, if the voltage optimization reference value issued by the intelligent fusion terminal is 232V, the system will adjust the local voltage compensation threshold to 229V-235V to achieve precise voltage control.

[0035] 5. Implementation effect verification of low-voltage distribution network coordinated regulation voltage autonomous device Within 30 days of the device's commissioning, the power quality and operational economic indicators of the distribution area significantly improved: Low-voltage distribution network coordinated regulation voltage autonomy device Voltage management effects: Voltage fluctuation range reduced from 195V-245V to 220V-235V, voltage over-limit occurrence rate reduced from 3 times per day to 0 times, and voltage qualification rate increased from 85% to 99.8%; Imbalance management effect of low-voltage distribution network collaborative regulation voltage self-regulation device: Three-phase imbalance decreased from 3.5% before the upgrade to below 1.8%, meeting the requirement of ≤2% in GB / T15543-2019 "Power Quality Three-phase Voltage Imbalance"; Renewable energy consumption effect of low-voltage distribution network collaborative regulation voltage self-regulation device: Reactive power utilization rate of photovoltaic inverter increased from 15% before the upgrade to 45%, and total power loss in the distribution area decreased by 7.5% (monthly power saving of approximately 800kWh); Equipment reliability of low-voltage distribution network collaborative regulation voltage self-regulation device: No faults during device operation, compensation command response time ≤500ms, meeting the dynamic management requirements of low-voltage distribution network.

[0036] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-voltage distribution network collaborative regulation voltage autonomous device, characterized in that, include: A four-layer architecture encompassing perception, decision-making, hierarchical execution, and multi-source collaboration. The sensing layer includes: a three-phase voltage acquisition module, a three-phase current acquisition module, an active power acquisition module, and a photovoltaic status monitoring module, which are used to acquire grid parameters and photovoltaic inverter operating data at minute intervals; The decision-making layer includes: a working condition clustering unit and a dual-objective hierarchical decision-making unit, which are used to perform working condition classification and priority determination; The hierarchical execution layer includes: a level-based coarse adjustment unit, a fine-tuning unit, and a strategy iteration unit; wherein, the level-based coarse adjustment unit is used to perform voltage over-limit coarse adjustment, the fine-tuning unit is used to perform three-phase imbalance management, and the strategy iteration unit is used to adjust the acquisition interval and iteratively correct the strategy according to the abnormal rules; low-voltage distribution network collaborative regulation voltage autonomous device. The multi-source collaboration layer includes a multi-protocol communication module and a photovoltaic inverter collaboration module, which are used to receive the substation-level collaboration limits of the intelligent converged terminal and to interact with the photovoltaic inverter for reactive power dispatching commands.

2. A method for coordinated voltage autonomy regulation in a low-voltage active distribution network, characterized in that, This is performed in conjunction with a photovoltaic inverter via a voltage autonomous device, and includes the following steps: S1: Operating Condition Classification and Data Acquisition: The device collects real-time data on three-phase voltage, three-phase current, distribution point switching power P, and photovoltaic inverter operating status of the low-voltage active distribution network. The operating conditions are further subdivided into two dimensions: voltage over-limit status and three-phase unbalance. The three-phase unbalance and its contribution are calculated simultaneously. The degree of voltage over-limit is classified according to the voltage value, and the three-phase unbalance is classified according to the ratio of the negative sequence component to the positive sequence component. S2: Dual-objective hierarchical judgment: Based on the typical operating conditions generated in step S1, a voltage priority fixed priority strategy is adopted: the first priority is the bidirectional voltage over-limit management, and the second priority is the three-phase imbalance management. S3: Tiered compensation implementation; S4: Distribution Area Coordination Threshold Adjustment: Every 30 minutes, the device receives the distribution area-level voltage coordination limit and photovoltaic consumption demand parameters issued by the intelligent fusion terminal via the LORA / HPLC protocol, dynamically updates the local voltage compensation threshold and the reactive power adjustment range of the photovoltaic inverter, and adapts to the needs of large-scale grid optimization and new energy consumption.

3. The low-voltage active distribution network coordinated regulation voltage autonomy method according to claim 2, characterized in that: The specific criteria for classifying the degree of voltage exceeding the limit in step S1 are as follows: a. Voltage below the lower limit: The voltage of any one of the three phases is below 198V; Low-voltage distribution network coordinated regulation voltage self-regulation device. b. Voltage generally exceeds the upper limit: the voltage of any one of the three phases is higher than 235V but lower than 253V; low-voltage distribution network coordinated regulation voltage self-regulation device. c. Voltage severely exceeds the upper limit: The voltage of any one of the three phases is higher than 253V.

4. The low-voltage distribution network coordinated regulation voltage autonomous device according to claim 3, characterized in that: The three-phase imbalance in step S1 is calculated using an empirical formula, which is: ； in, This refers to the three-phase current imbalance. , , These correspond to the effective voltage values ​​of phases a, b, and c, respectively.

5. The low-voltage active distribution network coordinated regulation voltage autonomy method according to claim 4, characterized in that: The three-phase imbalance contribution in step S1 is calculated using a formula, which is: ； in, Let be the effective value of the i-th phase voltage (i=a,b,c). The average value of the three-phase voltage; the adjustment sequence is from Compensation is applied sequentially from the highest phase to the lowest phase, gradually reducing the phase density. Up to ≤2%.

6. The low-voltage active distribution network coordinated regulation voltage autonomy method according to claim 2, characterized in that: Step S3 includes: S3.1: Coarse Adjustment for Voltage Exceeding Limits: The device performs coarse adjustment by adjusting capacitor switching or reactor adjustment according to the direction of the voltage exceeding the limit. This allows the voltage to quickly enter the acceptable range of 198V-235V; S3.2 Three-phase imbalance fine-tuning: After the voltage is qualified, if the three-phase imbalance is >2%, the key adjustment phase is located based on the contribution of the three-phase imbalance. The target phase's reactive power deficiency is accurately compensated by fine-tuning the grouped capacitors and coordinating with the reactive power of the photovoltaic inverter. S3.3 Abnormal Iteration: If the following abnormality occurs within the sampling interval: the voltage fluctuation exceeds 5V within 3 consecutive sampling periods, the sampling interval will be adjusted from 15 minutes to 5 minutes, and S3.1-S3.2 will be re-executed based on the new sampling data until the voltage stabilizes between 198V and 235V and the three-phase imbalance is stable at ≤2%.

7. The low-voltage active distribution network coordinated regulation voltage autonomy method according to claim 5, characterized in that: The compensation amount is based on the core formula: ； in The reactive power compensated by the device. The reactive power compensated by the photovoltaic inverter, R and X are the line resistance and reactance respectively, and P is the line active power. The specific allocation rules are as follows: a. Voltage over-limit management phase S3.1: Priority allocation Perform a coarse adjustment. Maintain the base compensation amount, i.e., maintain the power factor at 0.95; b. Three-phase imbalance mitigation stage S3.2: Maintain the voltage at the appropriate setting, utilizing the idle group capacitors and photovoltaic inverter within the device. The power factor is dynamically adjusted according to the unbalanced contribution to maintain it within the range of 0.9-1.

Images