Local control method and system for target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation

Abstract

The invention discloses a local control method and system for a target photovoltaic inverter to participate in voltage regulation of a photovoltaic grid-connected point. The method comprises the following steps: acquiring related parameters of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point; voltage acquisition is carried out on different nodes of the photovoltaic grid-connected points, and whether voltage out-of-limit occurs at different nodes of all the photovoltaic grid-connected points is judged; if voltage out-of-limit occurs to a node in a certain photovoltaic grid-connected point, the node controls a target photovoltaic inverter to adjust the voltage value of the node of the photovoltaic grid-connected point according to a voltage control strategy; and synchronizing the adjusted voltage value of the node of the photovoltaic grid-connected point to the other connected photovoltaic grid-connected points, and performing voltage adjustment on the other connected photovoltaic grid-connected points through a voltage control strategy until voltage adjustment of all the photovoltaic grid-connected points is completed. According to the invention, rapid and accurate voltage regulation can be realized, the voltage stability of a photovoltaic grid-connected point is improved, the impact on a power grid is reduced, and the overall efficiency of a photovoltaic system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems and smart grids, and in particular to an on-site control method and system for a target photovoltaic inverter to participate in voltage regulation of a photovoltaic grid-connected point. Background Art

[0002] In recent years, with the rapid development and widespread application of new energy technologies such as wind power generation and solar photovoltaic power generation, the proportion of these new energy resources connected to the distribution network has gradually increased. This trend has led to a significant change in the power system flow distribution, and the original single-direction power flow pattern has gradually changed to a two-way flow pattern. In some cases, this change may cause voltage over-limit problems, that is, the voltage value exceeds the normal operating range, which has a serious impact on the stability and safety of the power system.

[0003] In order to meet this challenge, the role of photovoltaic inverters as a key device has become increasingly prominent. Photovoltaic inverters can not only adjust active power, that is, the amount of power generated, but also adjust reactive power, that is, the adjustment of the phase difference between voltage and current in the power system. This regulation function is crucial to maintaining the stability of the grid voltage. In addition, photovoltaic inverters are relatively low in cost and have a fast response speed, which can respond quickly to changes in the grid in a short time.

[0004] Therefore, it is possible to make full use of these advantages of photovoltaic inverters to achieve efficient regulation of the voltage at the photovoltaic grid connection point. By accurately controlling the output of photovoltaic inverters, the voltage fluctuation problem caused by the access of new energy sources can be effectively alleviated, thereby ensuring the stable operation of the power system. This will not only help improve the overall performance of the power system, but also further promote the widespread application of new energy, promote the optimization of energy structure and promote green and low-carbon development. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above existing problems, the present invention is proposed.

[0007] Therefore, the present invention provides an on-site control method and system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation, which can solve the problems mentioned in the background technology.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] In a first aspect, the present invention provides an on-site control method for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation, comprising:

[0010] Obtain relevant parameters of the target photovoltaic inverter involved in the voltage regulation of the photovoltaic grid-connected point;

[0011] Collecting voltages at different nodes of the photovoltaic grid-connected points, and determining whether voltages at different nodes of all photovoltaic grid-connected points exceed a limit, wherein the photovoltaic grid-connected points are interconnected according to spatial distances and receive node voltage information from other photovoltaic grid-connected points;

[0012] If a node in a photovoltaic grid-connected point has a voltage exceeding the limit, the node controls the target photovoltaic inverter according to the voltage control strategy to adjust the voltage value of the photovoltaic grid-connected point node;

[0013] The adjusted voltage value of the photovoltaic grid-connected point node is synchronized to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust the voltage through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

[0014] As a preferred solution of the on-site control method for the target photovoltaic inverter participating in the photovoltaic grid-connected point voltage regulation described in the present invention, wherein: the acquisition of the relevant parameters of the target photovoltaic inverter participating in the photovoltaic grid-connected point voltage regulation includes: the relevant parameters include the starting voltage V1 of the target photovoltaic inverter reactive power absorption, the starting voltage V2 of the target photovoltaic inverter reactive power compensation, the starting voltage V3 of the target photovoltaic inverter active power regulation, the upper limit V max And the voltage lower limit V min .

[0015] As a preferred scheme of the on-site control method of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point described in the present invention, wherein: the judgment of whether the voltage exceeds the limit at different nodes of all photovoltaic grid-connected points includes: if the node voltage of any photovoltaic grid-connected point in the distribution network exceeds the range of 0.95pu to 1.05pu, it is considered that the voltage exceeds the limit.

[0016] As a preferred solution of the on-site control method of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point described in the present invention, wherein: if there is a node in a photovoltaic grid-connected point where the voltage exceeds the limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, including:

[0017] The voltage control strategy includes setting a capacity constraint of a target photovoltaic inverter, and the capacity constraint of the target photovoltaic inverter is as follows:

[0018] S N 2 =Q2 +P 2

[0019] Among them, Q is the photovoltaic reactive capacity of the target photovoltaic inverter, P is the photovoltaic active power of the target photovoltaic inverter; S N is the rated capacity of the Nth target PV inverter, and:

[0020] Q≤Q max

[0021] P≤P max

[0022] Among them, Q max is the maximum reactive capacity of the target PV inverter, P max is the maximum active output of the target PV inverter;

[0023] If the PV grid-connected point voltage V is less than the set PV grid-connected point voltage lower limit V min When the active power output of the photovoltaic inverter reaches the maximum P m1 , P m1 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the photovoltaic inverter has the maximum reactive power compensation capacity Q max At this time, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0024] P=P m1

[0025] Q=Q max

[0027] As a preferred solution of the on-site control method of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point described in the present invention, wherein: if there is a node in a photovoltaic grid-connected point where the voltage exceeds the limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes:

[0028] If the photovoltaic grid-connected point voltage V is less than the set target photovoltaic inverter reactive power absorption starting voltage V1, and is greater than the set photovoltaic grid-connected point voltage lower limit V min When the active power output of the photovoltaic inverter reaches the maximum P m2 , P m2 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0029] P=P m2

[0030]

[0031] If the PV grid-connected point voltage V is greater than the set target PV inverter reactive power absorption starting voltage V1, and less than the target PV inverter reactive power compensation starting voltage V2, the target PV inverter will not operate. At this time, the PV inverter active power output is maintained at P m2 , then the specific adjustments of the active power P and reactive power Q of the target PV inverter are as follows:

[0032] P=P m2

[0033] Q=0

[0035] As a preferred solution of the on-site control method of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point described in the present invention, wherein: if there is a node in a photovoltaic grid-connected point where the voltage exceeds the limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes:

[0036] If the photovoltaic grid-connected point voltage V is greater than the set target photovoltaic inverter reactive power compensation starting voltage V2, and less than the target photovoltaic inverter active power regulation starting voltage V3, then the photovoltaic inverter active power output reaches the maximum P m3 , P m3 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0037] P=P m3

[0038]

[0039] If the PV grid-connected point voltage V is greater than the set target PV inverter active power regulation start voltage V3, and less than the PV grid-connected point voltage upper limit V max When the active power output of the photovoltaic inverter reaches the maximum P m4 , P m4 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0040]

[0041] Q=-Q max

[0043] As a preferred solution of the on-site control method of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point described in the present invention, wherein: if there is a node in a photovoltaic grid-connected point where the voltage exceeds the limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes: if the photovoltaic grid-connected point voltage V is greater than the set photovoltaic grid-connected point voltage upper limit V max At this time, the target photovoltaic inverter is fully used to absorb reactive power, and the active power is 0. At this time, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0044] P=0

[0045] Q=-Q max

[0047] In a second aspect, the present invention provides an on-site control system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation, comprising:

[0048] A parameter acquisition module is used to acquire relevant parameters of a target photovoltaic inverter that participates in the voltage regulation of a photovoltaic grid-connected point;

[0049] A judgment module is used to collect voltages of different nodes of the photovoltaic grid-connected points and judge whether voltages of different nodes of all photovoltaic grid-connected points exceed the limit. The photovoltaic grid-connected points are interconnected according to spatial distances and receive node voltage information from other photovoltaic grid-connected points.

[0050] The first regulating module is used to control the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy if there is a node in the photovoltaic grid-connected point that exceeds the voltage limit;

[0051] The second regulation module is used to synchronize the adjusted voltage value of the photovoltaic grid-connected point node to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust the voltage through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

[0052] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method when executing the computer program.

[0053] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the method described above when executed by a processor.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention proposes an on-site control method and system for a target photovoltaic inverter to participate in the voltage regulation of a photovoltaic grid-connected point, obtains relevant parameters of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point; collects voltages of different nodes of the photovoltaic grid-connected point, and determines whether voltages of different nodes of all photovoltaic grid-connected points exceed the limit, the photovoltaic grid-connected points are interactively connected according to spatial distances, and receive node voltage information from other photovoltaic grid-connected points; if voltage exceeds the limit at a node in a photovoltaic grid-connected point, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy; synchronizes the adjusted voltage value of the photovoltaic grid-connected point node to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust voltages through the voltage control strategy until voltage regulation of all photovoltaic grid-connected points is completed. The present application is to achieve fast and accurate voltage regulation, improve the voltage stability of photovoltaic grid-connected points, and reduce the impact on the power grid and improve the overall efficiency of the photovoltaic system.

[0055] Specifically, the present invention can effectively deal with voltage fluctuations by real-time monitoring and adjusting the active power and reactive power output of the photovoltaic inverter. When the voltage exceeds the limit, the inverter can quickly adjust its output to ensure that the voltage remains within the set range. In addition, the present invention also takes into account the capacity constraints of the inverter to ensure that the maximum output capacity of the inverter is not exceeded during the adjustment process, thereby avoiding equipment damage and extending the service life of the equipment.

[0056] In practical applications, the control system of the present invention can automatically adjust the output of the inverter according to the real-time voltage conditions of the photovoltaic grid-connected points without manual intervention, greatly improving the automation and response speed of the system. At the same time, due to the use of spatial distance interactive connection, the various photovoltaic grid-connected points can coordinate with each other and jointly participate in voltage regulation, thereby achieving stable operation of the entire system.

[0057] In addition, the present invention has good scalability and compatibility, and can be applied to photovoltaic grid-connected points of different sizes and types. Through the coordinated use of computer equipment and computer-readable storage media, the method and system of the present invention can be easily integrated into the existing photovoltaic management system to achieve seamless connection with the existing system.

[0058] In summary, the on-site control method and system proposed in the present invention can not only effectively solve the problem of voltage fluctuation at the photovoltaic grid-connected point, but also have the advantages of simple operation, fast response, and system stability, and have high practical value and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0060] Figure 1 A method flow chart of an on-site control method and system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation provided by an embodiment of the present invention;

[0061] Figure 2 An internal structural diagram of a computer device of an on-site control method and system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0063] Example 1

[0064] Reference Figure 1-Figure 2 , which is the first embodiment of the present invention, provides a local control method and system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation, including:

[0065] Before describing the embodiments of the present application in detail, some related concepts are first explained for the sake of clarity.

[0066] Photovoltaic inverter: A photovoltaic inverter is a power electronic device that converts direct current (DC) generated by solar panels into alternating current (AC) so that it can be used by homes or commercial buildings, or fed into the public power grid. Photovoltaic inverters can not only convert electricity, but also monitor and manage the working status of solar power generation systems, and maximize the conversion of electricity generated by solar panels into usable electricity.

[0067] Photovoltaic grid connection point: The photovoltaic grid connection point refers to the place where the solar photovoltaic power generation system is connected to the power grid. At this point, the electricity generated by the solar system is injected into the power grid, or electricity is taken from the power grid to meet the load demand. Usually, the photovoltaic grid connection point is located near the distribution board or circuit breaker box on the user side, which is the location where the solar system interacts with the public power grid.

[0068] Voltage over-limit: Voltage over-limit means that the voltage value in the power grid exceeds the predetermined safe operating range. In the power system, the voltage must be kept within a certain range to ensure the normal operation of power equipment and the stable operation of the power system. If the voltage is too high or too low, it may damage the power equipment, affect the power supply quality, and even threaten the safety of the power system. For photovoltaic systems, voltage over-limit may be caused by the high penetration of renewable energy access to the power grid, because a large number of distributed power sources will change the power flow distribution in the power grid, thereby causing voltage fluctuations.

[0069] In the related art, there are some problems, such as untimely voltage regulation, slow system response, high risk of equipment damage and low degree of automation.

[0070] The present application provides a method that can effectively solve the above-mentioned problems. Next, a plurality of embodiments will be combined to elaborate on how to achieve the local control method of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point;

[0071] Figure 1 A method flow chart of an on-site control method and system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation is shown, including:

[0072] S101, obtaining relevant parameters of a target photovoltaic inverter participating in the voltage regulation of a photovoltaic grid-connected point;

[0073] In the embodiment of the present application, the relevant parameters of the target photovoltaic inverter participating in the photovoltaic grid-connected point voltage regulation are obtained, including: the relevant parameters include the starting voltage V1 of the target photovoltaic inverter reactive power absorption, the starting voltage V2 of the target photovoltaic inverter reactive power compensation, the starting voltage V3 of the target photovoltaic inverter active power regulation, the upper limit of the photovoltaic grid-connected point voltage V max And the voltage lower limit V min .

[0074] It should be noted that in addition to the parameters that must be obtained above, other parameters that may affect voltage regulation need to be obtained, such as ambient temperature, inverter temperature, grid load, etc. These parameters help to more accurately control the output of the inverter and ensure stable operation of the system.

[0075] It should be noted that the benefit of obtaining the above-mentioned parameters is that it can provide a clear adjustment threshold for the inverter, ensuring that the inverter can respond promptly and accurately when the voltage fluctuates. The setting of these parameters is based on a deep understanding of the characteristics of the power grid and the performance of the photovoltaic system to ensure that the voltage can be kept stable under different operating conditions.

[0076] S102, collecting voltages at different nodes of the photovoltaic grid-connected points, and determining whether voltages at different nodes of all photovoltaic grid-connected points exceed the limit, the photovoltaic grid-connected points are interconnected according to spatial distances, and receive node voltage information from other photovoltaic grid-connected points;

[0077] In an embodiment of the present application, determining whether voltage over-limit occurs at different nodes of all photovoltaic grid-connected points includes: if the node voltage of any photovoltaic grid-connected point in the distribution network exceeds the range of 0.95pu to 1.05pu, it is considered that voltage over-limit occurs.

[0078] In the embodiment of the present application, the specific selection of different nodes of the photovoltaic grid-connected point can be as follows:

[0079] PV inverter output: This is the first point where the DC power generated by the PV panels enters the grid after being converted to AC power by the inverter.

[0080] Distribution grid access point: This is the point where the PV system is connected to the public distribution grid, usually the user's meter location or distribution panel.

[0081] Branch line connection point: If the PV system contains multiple inverters or multiple grid connection points, the connection point of each inverter or grid connection point can be regarded as a different node.

[0082] Critical load access points: If the PV system supports certain critical loads (such as important equipment or important appliances in a residence), the access points of these loads can also serve as nodes.

[0083] Both sides of the transformer: If a transformer is used in the system to adjust the voltage level, the high-voltage side and the low-voltage side of the transformer can be considered as different nodes.

[0084] Distributed energy storage system access point: If an energy storage system (such as a battery pack) is integrated into the photovoltaic system, the access point of the energy storage system can also serve as a node.

[0085] Critical nodes in the grid: If a PV system is connected to multiple points of the grid, these connection points can also be considered different nodes.

[0086] In the embodiment of the present application, the interconnection of photovoltaic grid-connected points can be assumed to be interconnected through a certain communication network, so that each point can receive information from other points. In order to represent this connection relationship, a graph model in graph theory can be used. For example, suppose there is a set of photovoltaic grid-connected points {A1, A2, ..., A n}, where n is the number of grid-connected points. Each photovoltaic grid-connected point A i If there is a direct spatial connection between two points, then there is an edge between them.

[0087] The adjacency matrix M can be used to represent the connection relationship between photovoltaic grid-connected points. ij =1 indicates node A i and A j Directly connected. ij =0 indicates node A i and A j There are no direct connections; using a topological sort or other graph algorithm, it can be determined which nodes are adjacent, and node voltage information can be passed from one point to another.

[0088] For example, assume that there are two photovoltaic grid-connected points A1 and A2. They are directly connected, that is, M 12 =M 21 = 1. When A1 finds that its voltage is out of the normal range, it sends an alarm to all nodes connected to it (only A2 in this example), indicating that a voltage out-of-limit event has occurred. After receiving this information, A2 can make corresponding adjustments based on its own situation.

[0089] It should be noted that the benefit of the above step S102 is that it can monitor the voltage status of the entire distribution network in real time and promptly detect voltage limit problems. Through the photovoltaic grid-connected points that are interactively connected at spatial distances, information can be quickly transmitted and shared, thereby improving the response speed and reliability of the system. In addition, by judging the voltage status of each node, the problem can be more accurately located, providing a basis for subsequent voltage regulation.

[0090] S103, if there is a node in a photovoltaic grid-connected point where the voltage exceeds the limit, the node controls the target photovoltaic inverter according to the voltage control strategy to adjust the voltage value of the photovoltaic grid-connected point node;

[0091] In an embodiment of the present application, if a node in a photovoltaic grid-connected point has a voltage over-limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, including:

[0092] The voltage control strategy includes setting the capacity constraint of the target PV inverter. The capacity constraint of the target PV inverter is as follows:

[0093] S N 2 =Q 2 +P 2

[0094] Among them, Q is the photovoltaic reactive capacity of the target photovoltaic inverter, P is the photovoltaic active power of the target photovoltaic inverter; S N is the rated capacity of the Nth target PV inverter, and:

[0095] Q≤Q max

[0096] P≤P max

[0097] Among them, Q max is the maximum reactive capacity of the target PV inverter, P max is the maximum active output of the target PV inverter;

[0098] In the embodiment of the present application, if the photovoltaic grid-connected point voltage V is less than the set photovoltaic grid-connected point voltage lower limit V min When the active power output of the photovoltaic inverter reaches the maximum P m1 , P m1 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the photovoltaic inverter has the maximum reactive power compensation capacity Q max At this time, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0099] P=P m1

[0100] Q=Q max

[0102] In the embodiment of the present application, if a node in a photovoltaic grid-connected point has a voltage over-limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes:

[0103] If the photovoltaic grid-connected point voltage V is less than the set target photovoltaic inverter reactive power absorption starting voltage V1, and is greater than the set photovoltaic grid-connected point voltage lower limit V min When the active power output of the photovoltaic inverter reaches the maximum P m2 , P m2 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0104] P=P m2

[0105]

[0106] In the embodiment of the present application, if the photovoltaic grid-connected point voltage V is greater than the set target photovoltaic inverter reactive power absorption starting voltage V1, and less than the target photovoltaic inverter reactive power compensation starting voltage V2, the target photovoltaic inverter does not operate, and the photovoltaic inverter active power output maintains P m2 , then the specific adjustments of the active power P and reactive power Q of the target PV inverter are as follows:

[0107] P=P m2

[0108] Q=0

[0110] In the embodiment of the present application, if a node in a photovoltaic grid-connected point has a voltage over-limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes:

[0111] If the photovoltaic grid-connected point voltage V is greater than the set target photovoltaic inverter reactive power compensation starting voltage V2, and less than the target photovoltaic inverter active power regulation starting voltage V3, then the photovoltaic inverter active power output reaches the maximum P m3 , P m3 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0112] P=P m3

[0113]

[0114] In the embodiment of the present application, if the photovoltaic grid-connected point voltage V is greater than the set target photovoltaic inverter active power regulation start voltage V3, and less than the photovoltaic grid-connected point voltage upper limit V max When the active power output of the photovoltaic inverter reaches the maximum P m4 , P m4 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0115]

[0116] Q=-Q max

[0118] In the embodiment of the present application, if a node in a photovoltaic grid-connected point has a voltage over-limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes: if the photovoltaic grid-connected point voltage V is greater than the set photovoltaic grid-connected point voltage upper limit V max At this time, the target photovoltaic inverter is fully used to absorb reactive power, and the active power is 0. At this time, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

[0119] P=0

[0120] Q=-Q max

[0122] It should be noted that the benefit of the above step S103 is that the active power and reactive power output of the photovoltaic inverter can be flexibly adjusted according to the specific circumstances of the voltage over-limit event. In this way, the voltage can be effectively controlled within a safe range to avoid equipment damage or system instability caused by excessively high or low voltage.

[0123] S104, synchronizing the adjusted voltage value of the photovoltaic grid-connected point node to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust the voltage through a voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

[0124] In the embodiment of the present application, it is assumed that the photovoltaic grid point A i Adjust the voltage value to V i,new , for all i Connected photovoltaic grid point A j (i.e. M ij =1), V i,new Synchronize to A j .

[0125] Assume that the photovoltaic grid connection point A j Received from A i The voltage update V i ,new,A j Voltage adjustment is performed according to the following logic: Calculate A j The current voltage V j Deviation from the target voltage range [0.95pu, 1.05pu]. If V j Not within the target range, or with V i,new If there is a large deviation, then A j adjusts its own voltage output. If V j <0.95pu, increase the reactive power output of the inverter to increase the voltage. j >1.05pu, reduce the reactive power output of the inverter to lower the voltage. j Close to V i,new But it is not within the target range, so it is adjusted accordingly. Update A j The voltage value is V j,new And simultaneously give A j Other connected photovoltaic grid points.

[0126] For all photovoltaic grid-connected points A k Repeat the above process until the voltage of all photovoltaic grid-connected points is within the target range. An iterative method can be used, that is, each photovoltaic grid-connected point continuously adjusts the voltage and synchronizes information until the voltage of the entire system stabilizes.

[0127] It should be noted that the benefit of S104 is to ensure the voltage stability of the entire photovoltaic grid-connected system through coordinated control. This distributed voltage control strategy not only improves the flexibility and reliability of the system, but also can effectively cope with the impact of local voltage fluctuations on the entire system.

[0128] In an optional embodiment, the operating status of the entire photovoltaic grid-connected system can also be monitored to ensure that the system operates within a normal range. In the embodiment of the present application, the monitoring system includes but is not limited to key parameters such as voltage, current, frequency, and power factor. By monitoring these parameters in real time, abnormal conditions in the operation of the system can be discovered in a timely manner, and corresponding measures can be taken to adjust them.

[0129] In an optional embodiment, it can also be determined that when an abnormal system operating parameter is detected, an emergency response mechanism is activated. In the embodiment of the present application, the emergency response mechanism includes but is not limited to measures such as reducing the output power of the photovoltaic inverter, cutting off part of the load, and starting the backup power supply. Through these measures, the expansion of system failures can be effectively avoided and the safe and stable operation of the system can be ensured.

[0130] In an optional embodiment, the control strategy of the photovoltaic grid-connected system can also be optimized according to the system operating status and historical data. In the embodiment of the present application, the optimization process includes but is not limited to adjusting the voltage control strategy, optimizing the power control algorithm of the inverter, improving the system topology, etc. By continuously optimizing the control strategy, the operating efficiency of the system can be improved, energy consumption can be reduced, and the service life of the equipment can be extended.

[0131] In an optional embodiment, the photovoltaic grid-connected system can also be regularly maintained and inspected to ensure long-term stable operation of the system. In the embodiment of the present application, the maintenance and inspection work includes but is not limited to checking the cleanliness of the photovoltaic panels, checking the operating status of the inverter and the power distribution equipment, checking the reliability of the line connection, etc. Through regular maintenance and inspection, potential problems can be discovered in time to avoid the occurrence of system failures.

[0132] In summary, the present invention proposes an on-site control method for a target photovoltaic inverter to participate in the voltage regulation of a photovoltaic grid-connected point, obtains relevant parameters of the target photovoltaic inverter participating in the voltage regulation of the photovoltaic grid-connected point; performs voltage collection on different nodes of the photovoltaic grid-connected point, and determines whether the voltage exceeds the limit at different nodes of all photovoltaic grid-connected points, the photovoltaic grid-connected points are interactively connected according to spatial distance, and receive node voltage information from other photovoltaic grid-connected points; if there is a node in a photovoltaic grid-connected point that exceeds the limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy; synchronizes the adjusted voltage value of the photovoltaic grid-connected point node to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points perform voltage adjustment through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed. The present application is to achieve fast and accurate voltage regulation, improve the voltage stability of photovoltaic grid-connected points, and at the same time reduce the impact on the power grid and improve the overall efficiency of the photovoltaic system.

[0133] Specifically, the present invention can effectively deal with voltage fluctuations by real-time monitoring and adjusting the active power and reactive power output of the photovoltaic inverter. When the voltage exceeds the limit, the inverter can quickly adjust its output to ensure that the voltage remains within the set range. In addition, the present invention also takes into account the capacity constraints of the inverter to ensure that the maximum output capacity of the inverter is not exceeded during the adjustment process, thereby avoiding equipment damage and extending the service life of the equipment.

[0134] In practical applications, the control system of the present invention can automatically adjust the output of the inverter according to the real-time voltage conditions of the photovoltaic grid-connected points without manual intervention, greatly improving the automation and response speed of the system. At the same time, due to the use of spatial distance interactive connection, the various photovoltaic grid-connected points can coordinate with each other and jointly participate in voltage regulation, thereby achieving stable operation of the entire system.

[0135] In addition, the present invention has good scalability and compatibility, and can be applied to photovoltaic grid-connected points of different sizes and types. Through the coordinated use of computer equipment and computer-readable storage media, the method and system of the present invention can be easily integrated into the existing photovoltaic management system to achieve seamless connection with the existing system.

[0136] This embodiment also provides an on-site control system for a target photovoltaic inverter to participate in the voltage regulation of a photovoltaic grid-connected point, including:

[0137] A parameter acquisition module is used to acquire relevant parameters of a target photovoltaic inverter that participates in the voltage regulation of a photovoltaic grid-connected point;

[0138] The judgment module is used to collect voltages at different nodes of the photovoltaic grid-connected points and judge whether voltages at different nodes of all photovoltaic grid-connected points exceed the limit. The photovoltaic grid-connected points are interconnected according to spatial distances and receive node voltage information from other photovoltaic grid-connected points.

[0139] The first regulating module is used to control the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy if there is a node in the photovoltaic grid-connected point that exceeds the voltage limit;

[0140] The second regulation module is used to synchronize the adjusted voltage value of the photovoltaic grid-connected point node to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust the voltage through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

[0141] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0142] This embodiment also provides a computer device, which may be a terminal, and its internal structure diagram may be as shown in FIG. Figure 2 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for local control of a target photovoltaic inverter participating in the voltage regulation of a photovoltaic grid-connected point is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0143] This embodiment further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0144] Obtain relevant parameters of the target photovoltaic inverter involved in the voltage regulation of the photovoltaic grid-connected point;

[0145] The voltage of different nodes of the photovoltaic grid-connected points is collected, and it is determined whether the voltage of different nodes of all photovoltaic grid-connected points exceeds the limit. The photovoltaic grid-connected points are interactively connected according to the spatial distance, and all receive node voltage information from other photovoltaic grid-connected points;

[0146] If a node in a photovoltaic grid-connected point has a voltage exceeding the limit, the node controls the target photovoltaic inverter according to the voltage control strategy to adjust the voltage value of the photovoltaic grid-connected point node;

[0147] The adjusted voltage value of the photovoltaic grid-connected point node is synchronized to the other connected photovoltaic grid-connected points, and the other connected photovoltaic grid-connected points adjust the voltage through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

[0148] Example 2

[0149] Reference Figure 1-Figure 2 , which is an embodiment of the present invention, provides an on-site control method and system for a target photovoltaic inverter to participate in photovoltaic grid-connected point voltage regulation. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0150] Experiment date: 202* year * month ** day;

[0151] Number of photovoltaic grid-connected points: 10;

[0152] Photovoltaic inverter model: PV-Inverter-X;

[0153] Number of photovoltaic inverters: Each photovoltaic grid-connected point is equipped with one inverter;

[0154] The experimental data table is shown in the following table:

[0155]

[0156]

[0157] As shown in the above table, by comparing the experimental data, it can be seen that the new local control method shows significant superiority in different time periods. In particular, in terms of voltage over-limit times and voltage regulation time, the new local control method has significant improvements over the traditional control method. This shows that the local control system proposed in the present invention can effectively improve the voltage stability of the photovoltaic grid-connected point, shorten the voltage regulation time, and thus improve the operating efficiency and reliability of the entire photovoltaic system.

[0158] In addition, the experiment also recorded the system response time, that is, the time from the voltage limit to the system completing the voltage regulation. From the experimental data, it can be seen that the system response time of the new local control method is much lower than that of the traditional control method, which means that the new local control method can respond to voltage changes faster and make adjustments in time, thus ensuring the stable operation of the system.

[0159] In terms of equipment damage, no equipment damage occurred in either control method during the experiment, which shows that the on-site control system proposed in the present invention has good safety while ensuring the voltage regulation effect.

[0160] In summary, the local control system proposed by the present invention can not only effectively solve the voltage over-limit problem, shorten the voltage regulation time, and improve the system response speed, but also has good safety and reliability. Therefore, the system has a wide range of application prospects and can provide an efficient, stable and safe solution for the voltage regulation of photovoltaic grid-connected points.

[0161] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0162] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0163] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0164] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0165] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0166] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0167] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A local control method for a target photovoltaic inverter to participate in the voltage regulation of a photovoltaic grid-connected point, characterized in that: include: Obtain relevant parameters of the target photovoltaic inverter involved in the voltage regulation of the photovoltaic grid-connected point; Collecting voltages at different nodes of the photovoltaic grid-connected points, and determining whether voltages at different nodes of all photovoltaic grid-connected points exceed a limit, wherein the photovoltaic grid-connected points are interconnected according to spatial distances and receive node voltage information from other photovoltaic grid-connected points; If a node in a photovoltaic grid-connected point has a voltage exceeding the limit, the node controls the target photovoltaic inverter according to the voltage control strategy to adjust the voltage value of the photovoltaic grid-connected point node; The adjusted voltage value of the photovoltaic grid-connected point node is synchronized to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust the voltage through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

2. The on-site control method for the target photovoltaic inverter to participate in the photovoltaic grid-connected point voltage regulation as claimed in claim 1, characterized in that: The acquisition of the relevant parameters of the target photovoltaic inverter participating in the photovoltaic grid-connected point voltage regulation includes: the relevant parameters include the starting voltage V1 of the target photovoltaic inverter reactive power absorption, the starting voltage V2 of the target photovoltaic inverter reactive power compensation, the starting voltage V3 of the target photovoltaic inverter active power regulation, the photovoltaic grid-connected point voltage upper limit V max And the voltage lower limit V min .

3. The on-site control method for the target photovoltaic inverter to participate in the photovoltaic grid-connected point voltage regulation as claimed in claim 2, characterized in that: The determining whether voltage over-limit occurs at different nodes of all photovoltaic grid-connected points includes: if the node voltage of any photovoltaic grid-connected point in the distribution network exceeds the range of 0.95pu to 1.05pu, it is considered that voltage over-limit occurs.

4. The on-site control method for the target photovoltaic inverter to participate in the photovoltaic grid-connected point voltage regulation as claimed in claim 3, characterized in that: If a node in a photovoltaic grid-connected point has a voltage over-limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, including: The voltage control strategy includes setting a capacity constraint of a target photovoltaic inverter, and the capacity constraint of the target photovoltaic inverter is as follows: S N 2 =Q 2 +P 2 Among them, Q is the photovoltaic reactive capacity of the target photovoltaic inverter, P is the photovoltaic active power of the target photovoltaic inverter; S N is the rated capacity of the Nth target PV inverter, and: Q≤Q max P≤P max Among them, Q max is the maximum reactive capacity of the target PV inverter, P max is the maximum active output of the target PV inverter; If the PV grid-connected point voltage V is less than the set PV grid-connected point voltage lower limit V min When the active power output of the photovoltaic inverter reaches the maximum P m1 , P m1 According to the reactive power Q and the capacity constraint of the target photovoltaic inverter, the photovoltaic inverter has the maximum reactive power compensation capacity Q max At this time, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

5. The on-site control method for the target photovoltaic inverter to participate in the photovoltaic grid-connected point voltage regulation as claimed in claim 4, characterized in that: If a node in a photovoltaic grid-connected point has a voltage exceeding a limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and the step further includes: If the photovoltaic grid-connected point voltage V is less than the set target photovoltaic inverter reactive power absorption starting voltage V1, and is greater than the set photovoltaic grid-connected point voltage lower limit V min When the active power output of the photovoltaic inverter reaches the maximum P m2 , P m2 According to the reactive power Q and the capacity constraint of the target PV inverter, the active power P and reactive power Q of the target PV inverter are specifically adjusted as shown in the following formulas: P=P m2 If the PV grid-connected point voltage V is greater than the set target PV inverter reactive power absorption starting voltage V1, and less than the target PV inverter reactive power compensation starting voltage V2, the target PV inverter will not operate. At this time, the PV inverter active power output is maintained at P m2 , then the specific adjustments of the active power P and reactive power Q of the target PV inverter are as follows:

6. The on-site control method for the target photovoltaic inverter to participate in the photovoltaic grid-connected point voltage regulation as claimed in claim 5, characterized in that: If a node in a photovoltaic grid-connected point has a voltage exceeding a limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and the step further includes: If the photovoltaic grid-connected point voltage V is greater than the set target photovoltaic inverter reactive power compensation starting voltage V2, and less than the target photovoltaic inverter active power regulation starting voltage V3, then the photovoltaic inverter active power output reaches the maximum P m3 , P m3 According to the reactive power Q and the capacity constraint of the target PV inverter, the active power P and reactive power Q of the target PV inverter are specifically adjusted as shown in the following formulas: P=P m3 If the PV grid-connected point voltage V is greater than the set target PV inverter active power regulation start voltage V3, and less than the PV grid-connected point voltage upper limit V max When the active power output of the photovoltaic inverter reaches the maximum P m4 , P m4 According to the reactive power Q and the capacity constraint of the target PV inverter, the active power P and reactive power Q of the target PV inverter are specifically adjusted as shown in the following formulas:

7. The on-site control method for the target photovoltaic inverter to participate in the photovoltaic grid-connected point voltage regulation as claimed in claim 6, characterized in that: If a node in a photovoltaic grid-connected point has a voltage over-limit, the node controls the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy, and further includes: if the photovoltaic grid-connected point voltage V is greater than the set photovoltaic grid-connected point voltage upper limit V max At this time, the target photovoltaic inverter is fully used to absorb reactive power, and the active power is 0. At this time, the active power P and reactive power Q of the target photovoltaic inverter are specifically adjusted as shown in the following formulas:

8. An on-site control system for a target photovoltaic inverter to participate in the voltage regulation of a photovoltaic grid-connected point, characterized in that: include: A parameter acquisition module is used to acquire relevant parameters of a target photovoltaic inverter that participates in the voltage regulation of a photovoltaic grid-connected point; A judgment module is used to collect voltages of different nodes of the photovoltaic grid-connected points and judge whether voltages of different nodes of all photovoltaic grid-connected points exceed the limit. The photovoltaic grid-connected points are interconnected according to spatial distances and receive node voltage information from other photovoltaic grid-connected points. The first regulating module is used to control the target photovoltaic inverter to adjust the voltage value of the photovoltaic grid-connected point node according to the voltage control strategy if there is a node in the photovoltaic grid-connected point that exceeds the voltage limit; The second regulation module is used to synchronize the adjusted voltage value of the photovoltaic grid-connected point node to the remaining connected photovoltaic grid-connected points, and the remaining connected photovoltaic grid-connected points adjust the voltage through the voltage control strategy until the voltage regulation of all photovoltaic grid-connected points is completed.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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