Distribution network adjusting system and method based on distributed photovoltaic

Abstract

The invention relates to a distributed photovoltaic-based power distribution network adjusting system and method, the power distribution network adjusting system comprises a plurality of distributed photovoltaic units, a monitoring unit, a control center unit and a photovoltaic inverter, and the plurality of distributed photovoltaic units, the monitoring unit, the control center unit and the photovoltaic inverter are electrically connected with one another; the photovoltaic unit is connected to a line node of the power distribution network, and the photovoltaic unit is used for outputting a photovoltaic signal; the monitoring unit is used for monitoring the state of the power distribution network on the photovoltaic unit in real time and acquiring change information of voltage and frequency of the power distribution network; and the control center unit is used for receiving the change information, sending an adjusting instruction to the photovoltaic inverter according to the change information, and dynamically controlling the photovoltaic inverter. The power supply quality, the transmission efficiency, the stability and the reliability of the power distribution network can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of distributed photovoltaic power distribution networks, and in particular relates to a distribution network regulation system and method based on distributed photovoltaics. Background Art

[0002] With the global emphasis on environmental protection and sustainable development, the energy mix is ​​gradually shifting towards a low-carbon economy. Distributed photovoltaic power generation, thanks to its clean and flexible advantages, has rapidly grown its share of distribution networks, becoming a vital component of the renewable energy sector. However, the high penetration of distributed photovoltaic power generation in the grid presents numerous challenges to the stable operation of distribution networks. Because photovoltaic power generation depends on sunlight intensity and weather conditions, its output power is subject to significant fluctuations and intermittent behavior. This unstable power output can easily cause fluctuations in voltage and frequency within the distribution network, severely impacting power supply reliability and quality.

[0003] In the prior art, a series transformer is often used to regulate the voltage of the distribution network. The specific method is to connect a transformer in series between the photovoltaic grid-connected point and the load, and to achieve voltage regulation by adjusting the transformer's ratio. When faced with rapid changes in distributed photovoltaic power, the speed of transformer ratio adjustment is difficult to meet the real-time regulation requirements, resulting in poor voltage regulation. In addition, there are methods of using static compensation devices (such as capacitors, reactors) or series centralized voltage regulators for regulation. Although the static compensation device can improve the power factor to a certain extent, its response speed is slow and it cannot respond to sudden voltage fluctuations in a timely manner; the series centralized voltage regulator has poor flexibility and is difficult to accurately adjust according to the specific needs of different nodes.

[0004] Traditional grid regulation methods rely on large, centralized power plants to balance power supply and demand. During power transmission, factors such as line impedance and load fluctuations can cause voltage loss and frequency deviation, reducing power quality and transmission efficiency. Existing regulation technologies using static compensation devices or series-connected centralized voltage regulators suffer from response lags and poor flexibility, making them ineffective in addressing the challenges posed by distributed photovoltaic integration.

[0005] Therefore, the present invention provides a distributed photovoltaic-based distribution network regulation system and method to solve the above technical problems. Summary of the Invention

[0006] In response to the above problems, the purpose of the present invention is to provide a distribution network regulation system based on distributed photovoltaics, which can achieve precise regulation of the voltage and frequency of the distribution network by incorporating distributed photovoltaics into the distribution network and combining real-time monitoring and dynamic adjustment technology, thereby improving the power supply quality and transmission efficiency of the distribution network and ensuring the stable and reliable operation of the distributed photovoltaic distribution network.

[0007] In a first aspect, an embodiment of the present invention provides a distributed photovoltaic-based distribution network regulation system, the distribution network regulation system comprising a plurality of distributed photovoltaic units, a monitoring unit, a control center unit, and a photovoltaic inverter, wherein the plurality of distributed photovoltaic units, the monitoring unit, the control center unit, and the photovoltaic inverter are electrically connected to each other;

[0008] The distributed photovoltaic unit is connected to a line node of the power distribution network, and is used to output a photovoltaic signal;

[0009] The monitoring unit is used to monitor the status of the distribution network on the distributed photovoltaic unit in real time and obtain change information of the voltage and frequency of the distribution network;

[0010] The control center unit is used to receive the change information and send an adjustment instruction to the photovoltaic inverter according to the change information to dynamically control the photovoltaic inverter.

[0011] Preferably, the control center unit is further used for:

[0012] A 300kW photovoltaic system is connected at 2km, 5km, and 8km from the head end. The photovoltaic inverter supports ±0.9 power factor regulation. The following processing is performed by receiving the data transmitted by the monitoring unit:

[0013] When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to increase reactive power to increase the voltage;

[0014] When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to reduce reactive power and voltage;

[0015] When it is detected that the voltage of a certain node maintains the threshold, the reactive power of the photovoltaic inverter near the node is controlled to remain unchanged.

[0016] Preferably, the control center unit is further used for:

[0017] When the monitoring unit detects that the frequency of the distribution network deviates, the control center unit adjusts the active power output of the photovoltaic inverter according to the magnitude and direction of the frequency deviation;

[0018] If the frequency is lower than the rated value, the control center unit will instruct the photovoltaic inverter to increase active power output to supplement power for the distribution network and increase the frequency; if the frequency is higher than the rated value, the control center unit will instruct the photovoltaic inverter to reduce active power output to stabilize the frequency.

[0019] Preferably, the distribution network regulation system further includes an optimization unit, which is configured to coordinate the active and reactive outputs of the photovoltaic inverter through an optimization algorithm according to the change information of the voltage and the frequency.

[0020] Preferably, the optimization algorithm includes:

[0021] Using node admittance and power equations, predict the voltage changes of each node in the future time domain and predict the frequency deviation trend;

[0022] Establish the objective function: Where, ΔV t is the voltage deviation, Δf t is the frequency deviation, ΔP t is the active power regulation quantity, α, β, γ are weight coefficients, and T is the length of the optimized time window;

[0023] The predicted parameter values ​​are brought into the objective function to adjust the real-time power generation situation.

[0024] In a second aspect, an embodiment of the present invention provides a distribution network regulation method based on distributed photovoltaics, the distribution network regulation method comprising the following steps:

[0025] Connect to the line nodes of the distribution network through multiple distributed photovoltaic units to output photovoltaic signals;

[0026] Using a monitoring unit to monitor the state of the distribution network at the distributed photovoltaic unit in real time and obtain information on changes in the voltage and frequency of the distribution network;

[0027] receiving the change information through a control center unit, and generating an adjustment instruction according to the change information;

[0028] The adjustment instruction is sent to the photovoltaic inverter through the control center unit to dynamically control the operating state of the photovoltaic inverter.

[0029] Preferably, the distribution network regulation method further comprises the following steps:

[0030] A 300kW photovoltaic system is connected at 2km, 5km, and 8km from the head end. The photovoltaic inverter supports ±0.9 power factor regulation. The following processing is performed by receiving the data transmitted by the monitoring unit:

[0031] When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to increase reactive power to increase the voltage;

[0032] When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to reduce reactive power and voltage;

[0033] When it is detected that the voltage of a certain node maintains the threshold, the reactive power of the photovoltaic inverter near the node is controlled to remain unchanged.

[0034] Preferably, the distribution network regulation method further comprises the following steps:

[0035] When the monitoring unit detects that the frequency of the distribution network deviates, the control center unit adjusts the active power output of the photovoltaic inverter according to the magnitude and direction of the frequency deviation;

[0036] If the frequency is lower than the rated value, the control center unit will instruct the photovoltaic inverter to increase active power output to supplement power for the distribution network and increase the frequency; if the frequency is higher than the rated value, the control center unit will instruct the photovoltaic inverter to reduce active power output to stabilize the frequency.

[0037] Preferably, the distribution network regulation method further comprises the following steps:

[0038] According to the change information of the voltage and the frequency, the active and reactive outputs of the photovoltaic inverter are coordinated through an optimization algorithm.

[0039] Preferably, the optimization algorithm includes:

[0040] Using node admittance and power equations, predict the voltage changes of each node in the future time domain and predict the frequency deviation trend;

[0041] Establish the objective function: Where, ΔV t is the voltage deviation, Δf t is the frequency deviation, ΔP t is the active power regulation quantity, α, β, γ are weight coefficients, and T is the length of the optimized time window;

[0042] The predicted parameter values ​​are brought into the objective function to adjust the real-time power generation situation.

[0043] Compared with the related art, the present invention electrically connects multiple distributed photovoltaic units, monitoring units, control center units and photovoltaic inverters; the distributed photovoltaic units are connected to the line nodes of the distribution network, and the distributed photovoltaic units are used to output photovoltaic signals; the distributed photovoltaic units are dispersed along the line nodes of the distribution network, and the photovoltaic inverters near each node can be independently adjusted according to the actual operating conditions of the node; the monitoring unit is used to monitor the status of the distribution network on the distributed photovoltaic units in real time, and obtain the voltage and frequency change information of the distribution network; it can respond to power fluctuations more quickly, effectively reduce the fluctuation amplitude of voltage and frequency, and improve power supply stability; the control center unit is used to receive change information, and send adjustment instructions to the photovoltaic inverter according to the change information, and dynamically control the photovoltaic inverter; in this way, by incorporating distributed photovoltaics into the distribution network and combining real-time monitoring and dynamic adjustment technology, precise adjustment of the voltage and frequency of the distribution network can be achieved, the power supply quality and transmission efficiency of the distribution network can be improved, and the stable and reliable operation of the distributed photovoltaic distribution network can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A module diagram of a distributed photovoltaic-based distribution network regulation system provided in the first embodiment of the present invention;

[0045] Figure 2 A schematic diagram of line node allocation of a distributed photovoltaic-based distribution network regulation system provided in the first embodiment of the present invention;

[0046] Figure 3 This is a flow chart of a distribution network regulation method based on distributed photovoltaics provided in the second embodiment of the present invention.

[0047] In the figure, 100, a distribution network regulation system based on distributed photovoltaics, 1. Distributed photovoltaic unit, 2. Monitoring unit, 3. Control center unit, 4. Photovoltaic inverter, 5. Optimization unit. DETAILED DESCRIPTION

[0048] The present invention provides a distribution network regulation system based on distributed photovoltaics, aiming to solve the problems of low yield, high cost and complex process in traditional graphene preparation process, which cannot meet the requirements of industrialized and large-scale production.

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] Example 1

[0051] Please also refer to the attached Figure 1-Figure 2 The present invention provides a distribution network regulation system 100 based on distributed photovoltaics. The distribution network regulation system 100 includes multiple distributed photovoltaic units 1, a monitoring unit 2, a control center unit 3 and a photovoltaic inverter 4. The multiple distributed photovoltaic units 1, the monitoring unit 2, the control center unit 3 and the photovoltaic inverter 4 are electrically connected to each other.

[0052] The distributed photovoltaic unit 1 is connected to a line node of the distribution network and is used to output a photovoltaic signal. The distributed photovoltaic unit 1 can be connected in series or in parallel at a line node. This node has been carefully planned and has electrical parameters suitable for photovoltaic power access, such as a stable voltage level and appropriate short-circuit capacity. The photovoltaic panel array within the distributed photovoltaic unit 1 generates direct current (DC) under the influence of sunlight. After being converted by an inverter into AC power with the same frequency and phase as the distribution network, the distributed photovoltaic unit 1 outputs a photovoltaic signal containing specific voltage, current, and power information, which is injected into the line node to achieve power interaction with the distribution network.

[0053] Monitoring unit 2 is used to monitor the status of the distribution network connected to distributed photovoltaic units 1 in real time and obtain information on changes in the distribution network's voltage and frequency. Leveraging advanced sensor technology and an efficient data acquisition system, monitoring unit 2 provides comprehensive, real-time monitoring of the distribution network connected to distributed photovoltaic units 1. At the hardware level, it utilizes high-precision voltage and frequency sensors, tightly coupled to the distribution network's circuits. Like sensitive antennae, it senses subtle fluctuations in the distribution network's voltage and frequency in real time.

[0054] The collected raw voltage and frequency data is rapidly transmitted to the internal data processing module via monitoring unit 2. This module uses complex algorithms to conduct in-depth analysis and integration of this data, accurately determining whether the distribution network is currently operating normally and stably, experiencing mild abnormal fluctuations, or facing a serious abnormal state that could cause a failure. Once an abnormality such as voltage exceeding the normal fluctuation range, frequency deviating from the rated value, or a sudden voltage or frequency change is detected, monitoring unit 2 will immediately generate a detailed change information report, including the time the abnormality occurred, the specific changes in voltage and frequency, and their trends, etc. This provides a key basis for subsequent regulatory decisions and fully guarantees the coordinated and stable operation of the distributed photovoltaic unit 1 and the distribution network.

[0055] The control center unit 3 is used to receive the change information and send an adjustment instruction to the photovoltaic inverter 4 according to the change information to dynamically control the photovoltaic inverter 4.

[0056] Specifically, multiple distributed photovoltaic units 1, monitoring units 2, control center units 3 and photovoltaic inverters 4 are electrically connected to each other; the distributed photovoltaic units 1 are connected to the line nodes of the distribution network, and the distributed photovoltaic units 1 are used to output photovoltaic signals; the distributed photovoltaic units 1 are dispersedly connected along the distribution network line nodes, and the photovoltaic inverters 4 near each node can be independently adjusted according to the actual operating conditions of the node; the monitoring unit 2 is used to monitor the status of the distribution network on the distributed photovoltaic units 1 in real time, and obtain the change information of the voltage and frequency of the distribution network; it can respond to power fluctuations more quickly, effectively reduce the fluctuation amplitude of voltage and frequency, and improve power supply stability; the control center unit 3 is used to receive change information, and send adjustment instructions to the photovoltaic inverter 4 according to the change information, and dynamically control the photovoltaic inverter 4; in this way, by incorporating distributed photovoltaics into the distribution network and combining real-time monitoring and dynamic adjustment technology, accurate adjustment of the voltage and frequency of the distribution network can be achieved, the power supply quality and transmission efficiency of the distribution network can be improved, and the stable and reliable operation of the distributed photovoltaic distribution network can be ensured.

[0057] In this embodiment, the control center unit 3 is further used for:

[0058] A 300kW photovoltaic system is connected at 2km, 5km and 8km away from the head end respectively. The photovoltaic inverter 4 supports ±0.9 power factor regulation and performs the following processing by receiving the data transmitted back by the monitoring unit 2.

[0059] Specifically, the control center unit 3 plays a crucial role in the stable operation of the entire distribution network. It possesses a series of precise and efficient control strategies to meet the voltage regulation requirements under different operating conditions. Specifically, photovoltaic systems with a rated power of 300kW are connected at three specific locations on the distribution network line: 2km, 5km, and 8km from the headend. These photovoltaic systems are equipped with powerful photovoltaic inverters 4 that support a power factor adjustment range of ±0.9, providing a flexible and effective means for voltage regulation in the distribution network.

[0060] When it is detected that the voltage of a certain node is lower than the threshold, the photovoltaic inverter 4 near the node is controlled to increase reactive power and increase the voltage. Among them, when the control center unit 3 detects that the voltage of a certain node is lower than the preset threshold, it will immediately issue a precise control instruction to instruct the photovoltaic inverter 4 near the node to quickly increase reactive power. This process is achieved by precisely adjusting the power factor of the inverter. The inverter will dynamically adjust within the power factor range of ±0.9 it supports to increase the output of reactive power. As the reactive power increases, the voltage at the node will gradually increase, thereby restoring the voltage to the normal operating range. It should be noted that the threshold here can be pre-set according to the actual operating requirements and design standards of the distribution network. Common values ​​include 5V, 10V, etc., but the specific values ​​will vary depending on the different distribution network systems.

[0061] When the voltage at a node is detected to be below a threshold, the photovoltaic inverter 4 near that node is controlled to reduce reactive power and thus voltage. Conversely, when the voltage at a node is detected to be above a preset threshold, the control center unit 3 decisively issues a control command to control the photovoltaic inverter 4 near that node to reduce reactive power. Similarly, the photovoltaic inverter 4, based on the control command, appropriately reduces reactive power output within the power factor adjustment range, thereby lowering the node voltage and ensuring voltage stability within a safe and reasonable range.

[0062] When it detects that the voltage at a node remains at a threshold, the reactive power of the PV inverter 4 near that node is controlled to remain unchanged. Furthermore, when it detects that the voltage at a node remains at a preset threshold, the control center unit 3 controls the PV inverter 4 near that node to maintain its current reactive power output. This avoids unnecessary power regulation operations, reduces equipment losses, and helps maintain the stability and reliability of the distribution network.

[0063] Through the above series of precise control strategies, the control center unit 3 can effectively deal with the problem of voltage fluctuation in the distribution network, ensuring that the entire distribution network can maintain a stable and efficient operating state under various working conditions.

[0064] In this embodiment, the control center unit 3 is further used for:

[0065] When the monitoring unit 2 detects that the frequency of the power distribution network deviates, the control center unit 3 adjusts the active power output of the photovoltaic inverter 4 according to the magnitude and direction of the frequency deviation.

[0066] The control center unit 3 then activates its internal complex and intelligent decision-making system, and carries out orderly regulation work based on the specific size of the frequency deviation and the direction of the deviation (whether it is lower than or higher than the rated value). The core execution object of the regulation is the active output of the photovoltaic inverter 4.

[0067] If the frequency is lower than the rated value, the control center unit 3 will instruct the photovoltaic inverter 4 to increase the active power output to supplement the power for the distribution network and increase the frequency; if the frequency is higher than the rated value, the control center unit 3 will instruct the photovoltaic inverter 4 to reduce the active power output to stabilize the frequency.

[0068] Specifically, if the frequency is determined to be lower than the rated value, this means that the distribution network is facing a power shortage and urgently needs additional power to increase the frequency to the normal range. At this time, the control center unit 3 will accurately issue an instruction to increase active power output to the relevant photovoltaic inverter 4 through a high-speed, reliable data communication link. After receiving the instruction, the photovoltaic inverter 4 will respond quickly. Its internal power regulation module uses advanced power electronics technology to dynamically adjust its operating parameters. While ensuring safe and stable operation, it maximizes the output of active power, continuously delivering much-needed electricity to the distribution network, and helping the frequency gradually return to the rated value.

[0069] Conversely, if the monitoring data indicates a frequency higher than the rated value, this indicates excess power within the distribution network, potentially leading to system instability and other potential risks. Control center unit 3 immediately responds by sending a control signal to photovoltaic inverter 4 to reduce active power output. Upon receiving the command, photovoltaic inverter 4 rapidly reduces its own generated power, reducing the active power injected into the distribution network. This alleviates the excess power situation and effectively stabilizes the frequency of the distribution network, returning it to its normal operating range. Through this precise and timely regulation mechanism, control center unit 3 ensures that the frequency of the distribution network remains stable and reliable despite various complex operating conditions, providing a solid foundation for the safe and efficient operation of the entire power system.

[0070] In this embodiment, the power distribution network regulation system 100 further includes an optimization unit 5 , which is configured to coordinate the active and reactive outputs of the photovoltaic inverter 4 through an optimization algorithm according to the change information of the voltage and the frequency.

[0071] Specifically, optimization unit 5 also has dynamic adjustment and self-adaptation capabilities. The operating state of the distribution network is dynamic and is affected by various factors, such as light intensity and load changes. Optimization unit 5 tracks these changes in real time and adjusts the optimization strategy based on the latest voltage and frequency information to ensure optimal control under different operating conditions.

[0072] The optimization unit 5 plays a core role in the distribution network regulation system 100. Through advanced optimization algorithms and precise coordinated control, it effectively improves the stability, reliability and economy of the distribution network, and provides solid technical support for the large-scale access and efficient utilization of renewable energy.

[0073] In this embodiment, the optimization algorithm includes:

[0074] Using node admittance and power equations, predict the voltage changes of each node in the future time domain and predict the frequency deviation trend;

[0075] Establish the objective function: Where, ΔV t is the voltage deviation, Δf t is the frequency deviation, ΔP t is the active power regulation quantity, α, β, γ are weight coefficients, and T is the length of the optimized time window;

[0076] The predicted parameter values ​​are brought into the objective function to adjust the real-time power generation situation.

[0077] Specifically, ΔV t is the voltage deviation in the tth period, Δf t is the frequency deviation in the tth period, ΔP t is the active power regulation value for the tth period, and the weights α, β, and γ are used to adjust the priority of different deviation terms. The objective function achieves multi-period dynamic optimization by accumulating the squared sum of the deviations (voltage, frequency, and power) for each period. By adjusting the generator output, the weighted sum of the squares of the voltage and frequency deviations is minimized over T periods. This approach is applicable to dynamic economic dispatch of power systems, frequency stability control, and renewable energy grid connection optimization. T is the length of the time window defined in the optimization problem, which determines the algorithm's prediction and control range for future states. A larger T improves long-term optimization results but increases computational complexity; a smaller T is suitable for rapid response to short-term fluctuations.

[0078] Example 2

[0079] Please also refer to the attached Figure 1-Figure 3 As shown, an embodiment of the present invention provides a distribution network regulation method based on distributed photovoltaics, the distribution network regulation method comprising the following steps:

[0080] S1, connect to the line node of the distribution network through multiple distributed photovoltaic units 1, and output photovoltaic signals.

[0081] Step S1 specifically includes:

[0082] Connecting multiple distributed photovoltaic units 1 to different line nodes of the power distribution network respectively;

[0083] Each distributed photovoltaic unit 1 converts solar energy into electrical energy and outputs a photovoltaic signal containing a specific voltage and current to the distribution network.

[0084] S2. Use monitoring unit 2 to monitor the status of the distribution network at the photovoltaic unit in real time and obtain information on changes in the voltage and frequency of the distribution network.

[0085] Specifically, the voltage sensor and frequency sensor in the monitoring unit 2 are used to measure the voltage and frequency at the distribution network line node connected to the distributed photovoltaic unit 1 in real time; the measured voltage and frequency data are analyzed and processed to obtain the change information of the distribution network voltage and frequency.

[0086] S3. Receive the change information through the control center unit 3 and generate an adjustment instruction according to the change information.

[0087] Specifically, the control center unit 3 receives the change information of the distribution network voltage and frequency transmitted by the monitoring unit 2; compares the received voltage and frequency change information with the preset voltage and frequency thresholds; and generates adjustment instructions for the photovoltaic inverter 4 according to the preset control strategy based on the comparison result.

[0088] Among them, when it is detected that the voltage of a certain node is lower than the threshold, an instruction is generated to control the photovoltaic inverter 4 near the node to increase reactive power; when it is detected that the voltage of a certain node is higher than the threshold, an instruction is generated to control the photovoltaic inverter 4 near the node to reduce reactive power; when it is detected that the voltage of a certain node remains within the threshold range, an instruction is generated to control the photovoltaic inverter 4 near the node to keep the reactive power unchanged.

[0089] S4. Send the adjustment instruction to the photovoltaic inverter 4 through the control center unit 3 to dynamically control the operating state of the photovoltaic inverter 4.

[0090] The adjustment instructions generated by the control center unit 3 are sent to the corresponding photovoltaic inverter 4 through the communication network; after receiving the adjustment instructions, the photovoltaic inverter 4 adjusts its own active and reactive power output according to the instruction content to achieve regulation of the distribution network.

[0091] Specifically, by monitoring the state of the power grid in real time, it is possible to quickly obtain information on changes in voltage and frequency, and send adjustment instructions to the photovoltaic inverter 4 in a timely manner. Compared with the response lag problem of traditional static compensation devices, the present invention can respond to power fluctuations more quickly, effectively reduce the fluctuation amplitude of voltage and frequency, and improve power supply stability. Distributed photovoltaic units 1 are distributed along the nodes of the distribution network line, and the photovoltaic inverter 4 near each node can be independently adjusted according to the actual operating conditions of the node. This decentralized adjustment method can more accurately meet the adjustment needs of different nodes and improve the flexibility and pertinence of the adjustment. The present invention can not only effectively adjust the voltage and frequency separately, but also realize the coordinated stable control of voltage and frequency through the optimization algorithm. In the adjustment process, the mutual influence between the two is fully considered to avoid the adverse effect of a single adjustment on another parameter, thereby comprehensively improving the operating performance and power supply quality of the distribution network.

[0092] In this embodiment, the power distribution network regulation method further includes the following steps:

[0093] A 300kW photovoltaic system is connected at 2km, 5km, and 8km from the head end. The photovoltaic inverter 4 supports ±0.9 power factor regulation and performs the following processing by receiving the data transmitted by the monitoring unit 2:

[0094] When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter 4 near the node is controlled to increase reactive power and increase the voltage;

[0095] When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter 4 near the node is controlled to reduce reactive power and voltage;

[0096] When it is detected that the voltage of a certain node maintains the threshold value, the reactive power of the photovoltaic inverter 4 near the node is controlled to remain unchanged.

[0097] In this embodiment, the power distribution network regulation method further includes the following steps:

[0098] When the monitoring unit 2 detects that the frequency of the distribution network deviates, the control center unit 3 adjusts the active power output of the photovoltaic inverter 4 according to the magnitude and direction of the frequency deviation;

[0099] If the frequency is lower than the rated value, the control center unit 3 will instruct the photovoltaic inverter 4 to increase the active power output to supplement the power for the distribution network and increase the frequency; if the frequency is higher than the rated value, the control center unit 3 will instruct the photovoltaic inverter 4 to reduce the active power output to stabilize the frequency.

[0100] In this embodiment, the distribution network regulation method further includes the following steps: coordinating the active and reactive outputs of the photovoltaic inverter 4 through an optimization algorithm according to the change information of the voltage and the frequency.

[0101] In this embodiment, the optimization algorithm includes:

[0102] Using node admittance and power equations, predict the voltage changes of each node in the future time domain and predict the frequency deviation trend;

[0103] Establish the objective function: Where, ΔV t is the voltage deviation, Δf t is the frequency deviation, ΔP t is the active power regulation quantity, α, β, γ are weight coefficients, and T is the length of the optimized time window;

[0104] The predicted parameter values ​​are brought into the objective function to adjust the real-time power generation situation.

[0105] Specifically, ΔV t is the voltage deviation in the tth period, Δf t is the frequency deviation in the tth period, ΔP t is the active power regulation value for the tth period, and the weights α, β, and γ are used to adjust the priority of different deviation terms. The objective function achieves multi-period dynamic optimization by accumulating the squared sum of the deviations (voltage, frequency, and power) for each period. By adjusting the generator output, the weighted sum of the squares of the voltage and frequency deviations is minimized over T periods. This approach is applicable to dynamic economic dispatch of power systems, frequency stability control, and renewable energy grid connection optimization. T is the length of the time window defined in the optimization problem, which determines the algorithm's prediction and control range for future states. A larger T improves long-term optimization results but increases computational complexity; a smaller T is suitable for rapid response to short-term fluctuations.

[0106] The technical effects produced by the second embodiment are the same as those of the first embodiment, and will not be described one by one here.

[0107] It should be noted that the above-described embodiments are to be understood as illustrative and not limiting of the scope of protection of the present invention, which is subject to the claims. It will be apparent to those skilled in the art that non-essential improvements and adjustments to the present invention, without departing from the spirit and scope of the present invention, still fall within the scope of protection of the present invention.

Claims

1. A distribution network regulation system based on distributed photovoltaics, characterized in that: The distribution network regulation system includes a plurality of distributed photovoltaic units, a monitoring unit, a control center unit and a photovoltaic inverter, wherein the plurality of distributed photovoltaic units, the monitoring unit, the control center unit and the photovoltaic inverter are electrically connected to each other; The distributed photovoltaic unit is connected to a line node of the power distribution network, and is used to output a photovoltaic signal; The monitoring unit is used to monitor the status of the distribution network on the distributed photovoltaic unit in real time and obtain change information of the voltage and frequency of the distribution network; The control center unit is used to receive the change information and send an adjustment instruction to the photovoltaic inverter according to the change information to dynamically control the photovoltaic inverter.

2. The distributed photovoltaic power distribution network regulation system according to claim 1, characterized in that: The control center unit is also used for: A 300kW photovoltaic system is connected at 2km, 5km, and 8km from the head end. The photovoltaic inverter supports ±0.9 power factor regulation. The following processing is performed by receiving the data transmitted by the monitoring unit: When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to increase reactive power to increase the voltage; When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to reduce reactive power and voltage; When it is detected that the voltage of a certain node maintains the threshold, the reactive power of the photovoltaic inverter near the node is controlled to remain unchanged.

3. The distributed photovoltaic power distribution network regulation system according to claim 2, characterized in that: The control center unit is also used for: When the monitoring unit detects that the frequency of the distribution network deviates, the control center unit adjusts the active power output of the photovoltaic inverter according to the magnitude and direction of the frequency deviation; If the frequency is lower than the rated value, the control center unit will instruct the photovoltaic inverter to increase active power output to supplement power for the distribution network and increase the frequency; if the frequency is higher than the rated value, the control center unit will instruct the photovoltaic inverter to reduce active power output to stabilize the frequency.

4. The distributed photovoltaic power distribution network regulation system according to claim 1, characterized in that: The distribution network regulation system further includes an optimization unit, which is configured to coordinate the active and reactive outputs of the photovoltaic inverter through an optimization algorithm according to the change information of the voltage and the frequency.

5. The distributed photovoltaic-based distribution network regulation system according to claim 4, characterized in that: The optimization algorithm includes: Using node admittance and power equations, predict the voltage changes of each node in the future time domain and predict the frequency deviation trend; Establish the objective function: Where, ΔV t is the voltage deviation, Δf t is the frequency deviation, ΔP t is the active power regulation quantity, α, β, γ are weight coefficients, and T is the length of the optimized time window; The predicted parameter values ​​are brought into the objective function to adjust the real-time power generation situation.

6. A distribution network regulation method based on distributed photovoltaics, characterized in that: The distribution network regulation method comprises the following steps: Connect to the line nodes of the distribution network through multiple distributed photovoltaic units to output photovoltaic signals; Using a monitoring unit to monitor the state of the distribution network at the distributed photovoltaic unit in real time and obtain information on changes in the voltage and frequency of the distribution network; receiving the change information through a control center unit, and generating an adjustment instruction according to the change information; The adjustment instruction is sent to the photovoltaic inverter through the control center unit to dynamically control the operating state of the photovoltaic inverter.

7. The method for regulating the distribution network based on distributed photovoltaics according to claim 6, characterized in that: The distribution network regulation method further comprises the following steps: A 300kW photovoltaic system is connected at 2km, 5km, and 8km from the head end. The photovoltaic inverter supports ±0.9 power factor regulation. The following processing is performed by receiving the data transmitted by the monitoring unit: When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to increase reactive power to increase the voltage; When it is detected that the voltage of a certain node is lower than a threshold, the photovoltaic inverter near the node is controlled to reduce reactive power and voltage; When it is detected that the voltage of a certain node maintains the threshold, the reactive power of the photovoltaic inverter near the node is controlled to remain unchanged.

8. The method for regulating the distribution network based on distributed photovoltaics according to claim 6, characterized in that: The distribution network regulation method further comprises the following steps: When the monitoring unit detects that the frequency of the distribution network deviates, the control center unit adjusts the active power output of the photovoltaic inverter according to the magnitude and direction of the frequency deviation; If the frequency is lower than the rated value, the control center unit will instruct the photovoltaic inverter to increase active power output to supplement power for the distribution network and increase the frequency; if the frequency is higher than the rated value, the control center unit will instruct the photovoltaic inverter to reduce active power output to stabilize the frequency.

9. The method for regulating the distribution network based on distributed photovoltaics according to claim 6, characterized in that: The distribution network regulation method further comprises the following steps: According to the change information of the voltage and the frequency, the active and reactive outputs of the photovoltaic inverter are coordinated through an optimization algorithm.

10. The distribution network regulation method based on distributed photovoltaics according to claim 9, characterized in that: The optimization algorithm includes: Using node admittance and power equations, predict the voltage changes of each node in the future time domain and predict the frequency deviation trend; Establish the objective function: Where, ΔV t is the voltage deviation, Δf t is the frequency deviation, ΔP t is the active power regulation quantity, α, β, γ are weight coefficients, and T is the length of the optimized time window; The predicted parameter values ​​are brought into the objective function to adjust the real-time power generation situation.

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