A power distribution network voltage out-of-limit suppression method, device and equipment based on photovoltaic dynamic output ratio sensing and a storage medium

Abstract

The application discloses a power distribution network voltage out-of-limit suppression method and device based on photovoltaic dynamic output ratio sensing, equipment and storage medium, comprising: performing direct current power flow analysis on power grid data, and determining the active power-voltage droop coefficient of each photovoltaic node in the power distribution network according to the analysis result; obtaining the output voltage and output current of each photovoltaic component in the power distribution network, and inputting the output voltage and output current into a pre-constructed dynamic output ratio sensing model to determine the direct current side stress parameter; obtaining the voltage of each photovoltaic grid-connected point in the power distribution network, and inputting the voltage into an active power-voltage droop controller constructed based on the active power-voltage droop coefficient to determine the alternating current side stress parameter; and taking the direct current side stress parameter as the outer loop controlled variable of the outer loop control loop of the power distribution network, and taking the alternating current side stress parameter as the outer loop control of the outer loop control loop to perform voltage out-of-limit suppression on the power distribution network.

Description

Technical Field

[0001] This invention belongs to the field of power distribution networks and relates to methods for suppressing voltage over-limits, particularly to a method, device, equipment, and storage medium for suppressing voltage over-limits in power distribution networks based on photovoltaic dynamic output ratio sensing. Background Technology

[0002] With the rapid growth of residential distributed photovoltaic (PV) systems, high-penetration PV low-voltage distribution networks have become the norm. High-penetration PV cannot be locally absorbed in low-voltage distribution networks, easily leading to reverse power flow in the grid, which in turn causes the voltage of the end-point power supply system to exceed the safety threshold, resulting in voltage exceeding limits.

[0003] Current research on voltage limit suppression primarily focuses on medium- and high-voltage distribution networks, employing control strategies such as centralized power regulation, energy storage coordinated control, on-load tap changer regulation, and decentralized power regulation. Centralized voltage regulation requires real-time monitoring of the entire distribution network parameters, resulting in high costs and stringent communication requirements. Most low-voltage distribution networks have poor communication conditions, making this control strategy impractical. In contrast, decentralized voltage regulation only requires local or block-based regulation according to predefined control logic, has lower construction costs, and offers stable and reliable operation.

[0004] In related technologies, since the R / X ratio of medium and high voltage distribution networks is much smaller than that of low voltage distribution networks, the reactive power voltage regulation effect is much smaller than that of active power regulation. This leads to the inability of traditional distributed active power regulation to achieve uniform reduction of photovoltaic output power in the distribution network when voltage regulation is lacking, which will cause the imbalance of income and expenditure rates among different household distributed photovoltaic entities. Summary of the Invention

[0005] In view of this, the present invention discloses a method, device, equipment and storage medium for suppressing voltage over-limit in distribution networks based on photovoltaic dynamic output ratio sensing, which can solve the shortcomings of related technologies.

[0006] To achieve the above objectives, the present invention discloses the following technical solution:

[0007] According to a first aspect of the present invention, a method for suppressing voltage exceedances in distribution networks based on photovoltaic dynamic output ratio sensing is proposed, the method comprising:

[0008] In response to the acquired power grid data of each node and line in the distribution network, DC power flow analysis is performed on the power grid data, and the active power output-voltage droop coefficient of each photovoltaic node in the distribution network is determined based on the analysis results.

[0009] The output voltage and output current of each photovoltaic module in the power distribution network are obtained, and the output voltage and output current are input into a pre-constructed dynamic output ratio sensing model so as to determine the dynamic photovoltaic output ratio output by the sensing model as the DC side stress parameter.

[0010] The voltage of each photovoltaic grid-connected point in the distribution network is obtained and input into the active power output-voltage droop controller constructed based on the active power output-voltage droop coefficient, so that the output of the active power output-voltage droop controller is determined as the AC side stress parameter.

[0011] The DC-side stress parameter is used as the outer loop controlled variable of the outer loop control loop of the distribution network, and the AC-side stress parameter is used as the outer loop control of the outer loop control loop to suppress voltage over-limit in the distribution network.

[0012] According to a second aspect of the present invention, a distribution network voltage over-limit suppression device based on photovoltaic dynamic output ratio sensing is provided, the device comprising:

[0013] Analysis unit: In response to the acquired power grid data of each node and line in the distribution network, performs DC power flow analysis on the power grid data, and determines the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results;

[0014] First acquisition unit: acquires the output voltage and output current of each photovoltaic module in the distribution network, and inputs the output voltage and output current into a pre-constructed dynamic output ratio sensing model, so as to determine the dynamic photovoltaic output ratio output by the sensing model as the DC side stress parameter;

[0015] The second acquisition unit acquires the voltage of each photovoltaic grid-connected point in the distribution network and inputs it into the active power output-voltage droop controller constructed based on the active power output-voltage droop coefficient, so as to determine the output of the active power output-voltage droop controller as the AC side stress parameter.

[0016] Control unit: The DC-side stress parameter is used as the outer loop controlled variable of the outer loop control loop of the distribution network, and the AC-side stress parameter is used as the outer loop control of the outer loop control loop to suppress voltage over-limit of the distribution network.

[0017] According to a third aspect of the present invention, an electronic device is provided, comprising:

[0018] processor;

[0019] Memory used to store processor-executable instructions;

[0020] The processor implements the steps of the method as described in the first aspect by running the executable instructions.

[0021] According to a fourth aspect of the invention, a computer-readable storage medium is provided having computer instructions stored thereon that, when executed by a processor, implement the steps of the method as described in the first aspect.

[0022] As can be seen from the above technical solutions, the distribution network voltage over-limit suppression method based on photovoltaic dynamic output ratio sensing disclosed in this invention requires relatively easy-to-obtain data, thus requiring less communication and can operate in low-communication environments. It is also easy to port and has low construction costs. Furthermore, by suppressing voltage over-limits in the distribution network through the output of the active power output-voltage droop controller and the sensing model, photovoltaic output can be reduced fairly and proportionally, thereby avoiding the imbalance of income and expenditure rates among different residential distributed photovoltaic entities. Attached Figure Description

[0023] Figure 1 This is a flowchart of an exemplary embodiment of a distribution network voltage over-limit suppression method based on photovoltaic dynamic output ratio sensing.

[0024] Figure 2 This is a schematic diagram of a dual-loop control circuit provided in an exemplary embodiment.

[0025] Figure 3 This is a schematic diagram of a photovoltaic power output ratio provided in an exemplary embodiment.

[0026] Figure 4 This is a schematic structural diagram of a device provided in an exemplary embodiment.

[0027] Figure 5 This is a block diagram of a distribution network voltage over-limit suppression device based on photovoltaic dynamic output ratio sensing, provided as an exemplary embodiment. Detailed Implementation

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of the present invention as detailed in the appended claims.

[0029] It should be noted that the steps of the corresponding methods in other embodiments are not necessarily performed in the order shown and described in this invention. In some other embodiments, the methods may include more or fewer steps than those described in this invention. Furthermore, a single step described in this invention may be broken down into multiple steps in other embodiments; and multiple steps described in this invention may be combined into a single step in other embodiments.

[0030] To further illustrate the present invention, the following embodiments are provided:

[0031] With the rapid growth of residential distributed photovoltaic (PV) systems, high-penetration PV low-voltage distribution networks have become the norm. High-penetration PV cannot be locally absorbed in low-voltage distribution networks, easily leading to reverse power flow in the grid, which in turn causes the voltage of the end-point power supply system to exceed the safety threshold, resulting in voltage exceeding limits.

[0032] Current research on voltage limit suppression primarily focuses on medium- and high-voltage distribution networks, employing control strategies such as centralized power regulation, energy storage coordinated control, on-load tap changer regulation, and decentralized power regulation. Centralized voltage regulation requires real-time monitoring of the entire distribution network parameters, resulting in high costs and stringent communication requirements. Most low-voltage distribution networks have poor communication conditions, making this control strategy impractical. In contrast, decentralized voltage regulation only requires local or block-based regulation according to predefined control logic, has lower construction costs, and offers stable and reliable operation.

[0033] In related technologies, since the R / X ratio of medium and high voltage distribution networks is much smaller than that of low voltage distribution networks, the reactive power voltage regulation effect is much smaller than that of active power regulation. This leads to the inability of traditional distributed active power regulation to achieve uniform reduction of photovoltaic output power in the distribution network when voltage regulation is lacking, which will cause the imbalance of income and expenditure rates among different household distributed photovoltaic entities.

[0034] To address the shortcomings of related technologies, this invention proposes a method for suppressing voltage over-limit in distribution networks based on photovoltaic dynamic output ratio sensing.

[0035] Figure 1 This is a flowchart illustrating an exemplary embodiment of a distribution network voltage over-limit suppression method based on photovoltaic dynamic output ratio sensing. (Example:) Figure 1 As shown, the method may include the following steps:

[0036] Step 102: In response to the acquired power grid data of each node and line in the distribution network, perform DC power flow analysis on the power grid data, and determine the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results.

[0037] The distribution network is a crucial component of the power system, responsible for stepping down the high-voltage electricity transmitted from the transmission network and distributing it to various electricity users. A photovoltaic (PV) node is a specific point in the distribution network connected to a photovoltaic (PV) power generation system. A PV system typically includes solar panels, inverters, and other necessary components that convert solar energy into electrical energy, which is then fed into the distribution network through this node. Non-PV nodes refer to all other nodes in the distribution network that are not connected to a PV power generation system. These nodes may be connected to traditional power generation resources (such as thermal power, hydropower, etc.) or simply other connection points within the distribution network.

[0038] DC power flow analysis is a fundamental tool in power system analysis, primarily used to assess the operation of a power system under steady-state conditions. The main analysis steps include: establishing a network model: determining the type of all nodes (load nodes, generator nodes, slack nodes), and determining the parameters of all branches, including resistance, reactance, and transformer turns ratio; forming a node admittance matrix: using branch parameters to form a node admittance matrix (Y-Bus matrix); selecting a reference node: typically, the slack node is chosen as the reference node, with its voltage phase angle set to 0; establishing power equations: for each node, establishing active power equations according to its type (load node, generator node); solving the equation set: forming a system of equations about the node voltage phase angle and solving the system; calculating branch power and voltage: using the obtained voltage phase angles to calculate the active power of each branch and the voltage of each node; analyzing results: checking the load conditions of each branch to ensure that they do not exceed the thermal limit, and checking whether the node voltages are within the allowable range.

[0039] In one embodiment, the step of performing DC power flow analysis on the power grid data and determining the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results includes: analyzing the distribution network model constructed based on the power grid data to establish a full network Jacobian impedance matrix; determining the correlation between voltage change and photovoltaic power output ratio change based on the full network Jacobian impedance matrix; and adjusting the active power output-voltage droop coefficient based on the correlation.

[0040] Furthermore, the DC power flow analysis of the power grid data includes: reducing the effect of the imaginary part of the power flow on the voltage during the DC power flow analysis process.

[0041] A model analysis of the low-voltage distribution network was performed, and the relationships between node voltages are as follows:

[0042]

[0043] Among them, U m U represents the voltage at node m of a single line; m+1 P represents the voltage at node m+1 of a single line. kInjecting active power at a certain node; Q k Injecting reactive power at a certain node; R m Q represents the line resistance at nodes m and m+1 of a single line. m The line reactance at nodes m and m+1 of a single line.

[0044] The Jacobian impedance matrix of the entire network can be established using the above formula:

[0045]

[0046] Where ΔU represents the change in voltage amplitude at each node; Δθ represents the change in phase at each node; B is the Jacobian matrix of network voltage and power changes; ΔP represents the change in active power at each node; and ΔQ represents the change in reactive power at each node.

[0047] The high R / X ratio of low-voltage distribution networks indicates the low impact of Δθ and ΔQ, and further, the strong correlation between ΔU and ΔP can be determined.

[0048] The main change in ΔP is the active power output of the photovoltaic module, which can be further derived as the correlation between voltage change and photovoltaic power output ratio change ΔU / Δη. PV This enables the tuning of the photovoltaic output ratio-voltage droop coefficient.

[0049] The voltage-active power output ratio droop controller can be constructed from the above droop coefficients, i.e.

[0050] η PV * =1+m(UU) min );

[0051] Where, η PV * Here, m is the photovoltaic output ratio reference value, m is the photovoltaic output ratio minus the voltage droop coefficient, and U is the voltage at the current node's grid connection point. min To suppress downlink voltage when the current node voltage exceeds the limit.

[0052] Step 104: Obtain the output voltage and output current of each photovoltaic module in the power distribution network, and input the output voltage and output current into the pre-constructed dynamic output ratio sensing model, so as to determine the dynamic photovoltaic output ratio output by the sensing model as the DC side stress parameter.

[0053] In one embodiment, the dynamic output ratio sensing model is:

[0054]

[0055] Where, η PVThe dynamic photovoltaic output ratio is used to characterize the ratio of the actual output active power of a photovoltaic module to the maximum output active power. 'a' represents the first-order linear coefficient of the fitted graph, 'b' represents the linear intercept of the fitted graph, and U... pv For the output voltage, I pv Let dI be the output current. pv dU represents the change in photovoltaic current. pv This represents the change in photovoltaic voltage.

[0056] Furthermore, the dynamic photovoltaic power ratio output by the dynamic power ratio sensing model is limited to a range of 0.75 to 1 to avoid poor control performance caused by fitting errors.

[0057] Step 106: Obtain the voltage of each photovoltaic grid-connected point in the distribution network and input it into the active power output-voltage droop controller constructed based on the active power output-voltage droop coefficient, so as to determine the output of the active power output-voltage droop controller as the AC side stress parameter.

[0058] Step 108: The DC-side stress parameter is used as the outer loop controlled variable of the outer loop control loop of the distribution network, and the AC-side stress parameter is used as the outer loop control of the outer loop control loop, so as to suppress voltage over-limit of the distribution network.

[0059] In this embodiment, the data required for the distribution network voltage over-limit suppression method based on photovoltaic dynamic output ratio sensing is relatively easy to obtain. Therefore, its communication requirements are low, it can operate in low-communication environments, and it is easy to port and has low construction costs. Furthermore, by using the output of the active power output-voltage droop controller and the sensing model to suppress voltage over-limits in the distribution network, photovoltaic output can be reduced fairly and proportionally, thereby avoiding the problem of income-expenditure imbalance among different residential distributed photovoltaic entities.

[0060] In one embodiment, the control loop of the distribution network is a PI dual-loop control loop, and the inner loop of the PI dual-loop control loop is a grid-connected side current control loop. The method further includes: using the grid-connected current d-axis reference value of the distribution network as the outer loop output parameter; using the grid-connected current dq-axis current of the distribution network as the inner loop controlled variable; using the grid-connected current d-axis reference value as the inner loop control variable; and using the switching sequence and switching time of the converter of the distribution network as the inner loop output parameter.

[0061] like Figure 2 As shown, the photovoltaic grid-connected architecture of this invention is a DC / AC single-stage topology, which generates the photovoltaic output voltage U through the DC-side voltage regulator capacitor. pv Real-time data acquisition is used to measure the photovoltaic output current I at the DC-side positive terminal. pv Real-time data acquisition, and grid-connected current I of AC filter inductor. gVoltage U g The data is collected in real time, and after being processed by the voltage over-limit suppression method described in this invention, the switching sequence and switching time of the converter are controlled.

[0062] The control loop used in this example is a PI dual-loop control loop. The outer loop controls the photovoltaic output ratio η output by the DC-side dynamic output ratio sensing model. PV As the outer-loop controlled variable, the photovoltaic output ratio reference value η output by the voltage-active power output ratio droop controller is... PV * As the outer loop control variable, the grid-connected current d-axis reference value I gd * As the outer loop output parameter, the inner loop is controlled by the grid-connected current dq axis current I. gd I gq As the controlled variable in the inner loop, the grid-connected current d-axis reference value I gd * As inner-loop control variables, the switching sequence and conduction time d of the converter's switching transistors are used as inner-loop output parameters.

[0063] The real-time DC-side data is processed by a dynamic power ratio sensing model to output the current sensed photovoltaic power ratio η. PV This photovoltaic power output ratio is not the actual dynamic power output ratio of the photovoltaic modules, but rather a dynamic power output ratio predicted by fitting two parameters. Figure 3 This can express the difference between the two parameters mentioned above, where η PV,X Indicates the output voltage U of the photovoltaic system pv and photovoltaic output current I pv The dynamic output ratio, Δη, is predicted by fitting the dynamic output ratio sensing model. PV This represents the difference between the actual dynamic power output ratio of the photovoltaic module and the fitted predicted dynamic power output ratio. Analysis can reveal the difference between the predicted value and the actual dynamic power output ratio of the photovoltaic module when the photovoltaic module reaches its maximum output (i.e., η). PV A value of 1) perfectly overlaps and is unaffected by irradiance. However, under the same irradiance, the deviation between the predicted value and the actual value gradually increases as the predicted value decreases. Therefore, it is necessary to select an appropriate sensing prediction range.

[0064] In one embodiment, determining the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results includes: selecting the center value of the high-frequency fluctuation area of ​​residential load as the node load, in order to consider actual application needs and expand the control range.

[0065] In one embodiment, the dynamic output ratio sensing model can be upgraded or piecewise fitted based on the fitting effect, with the aim of reducing the fitting error and expanding the effective control range.

[0066] In one embodiment, the collected grid connection point voltage needs to be converted into dq coordinates via Park transformation and the d-axis voltage is used as a reference value. The purpose is to achieve feedback control of the voltage during power regulation.

[0067] Figure 4 This is a schematic structural diagram of a device provided in an exemplary embodiment. Please refer to... Figure 4 At the hardware level, the device includes a processor 402, an internal bus 404, a network interface 406, memory 408, and non-volatile memory 410, and may also include other hardware required for its functions. One or more embodiments of the present invention can be implemented in software, for example, the processor 402 reads the corresponding computer program from the non-volatile memory 410 into memory 408 and then runs it. Of course, in addition to software implementation, one or more embodiments of the present invention do not exclude other implementation methods, such as logic devices or a combination of hardware and software, etc. That is to say, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0068] Please refer to Figure 5 A distribution network voltage over-limit suppression device based on photovoltaic dynamic output ratio sensing can be applied to, for example... Figure 5 The device shown, in order to implement the technical solution of the present invention, may include:

[0069] Analysis unit 502 is used to perform DC power flow analysis on the acquired power grid data of each node and line in the distribution network, and determine the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results.

[0070] The first acquisition unit 504 is used to acquire the output voltage and output current of each photovoltaic module in the distribution network, and input the output voltage and output current into a pre-constructed dynamic output ratio sensing model, so as to determine the dynamic photovoltaic output ratio output by the sensing model as a DC side stress parameter.

[0071] The second acquisition unit 506 is used to acquire the voltage of each photovoltaic grid connection point in the distribution network and input it into the active power output-voltage droop controller constructed based on the active power output-voltage droop coefficient, so as to determine the output of the active power output-voltage droop controller as the AC side stress parameter.

[0072] The control unit 508 is used to use the DC-side stress parameter as the outer loop controlled variable of the outer loop control loop of the distribution network, and to use the AC-side stress parameter as the outer loop control of the outer loop control loop, so as to suppress voltage over-limit of the distribution network.

[0073] Optionally, the analysis unit 502 is specifically used for:

[0074] The distribution network model constructed based on the power grid data is analyzed to establish the Jacobian impedance matrix of the entire network;

[0075] The correlation between voltage change and photovoltaic output ratio change is determined based on the full network Jacobian impedance matrix, and the active power output-voltage droop coefficient is tuned based on the correlation.

[0076] Optionally, the dynamic output ratio sensing model is:

[0077]

[0078] Where, η PV The dynamic photovoltaic output ratio is used to characterize the ratio of the actual output active power of a photovoltaic module to the maximum output active power. 'a' represents the first-order linear coefficient of the fitted graph, 'b' represents the linear intercept of the fitted graph, and U... pv For the output voltage, I pv Let dI be the output current. pv dU represents the change in photovoltaic current. pv This represents the change in photovoltaic voltage.

[0079] Optionally, the dynamic photovoltaic power ratio output by the dynamic power ratio sensing model is limited to a range of 0.75 to 1.

[0080] Optionally, the control loop of the distribution network is a PI dual-loop control loop, and the inner loop of the PI dual-loop control loop is a grid-connected side current control loop. The method further includes:

[0081] The outer loop output unit 510 is used to take the grid-connected current d-axis reference value of the distribution network as the outer loop output parameter;

[0082] The inner loop control unit 512 is used to take the grid-connected current dq-axis current of the distribution network as the inner loop controlled variable, the grid-connected current d-axis reference value as the inner loop control variable, and the switching sequence and switching time of the converter of the distribution network as the inner loop output parameter.

[0083] Optionally, the analysis unit 502 is specifically used for:

[0084] In the process of DC power flow analysis, the effect of the imaginary part of the power flow on voltage is reduced.

[0085] Optionally, the first acquisition unit 504 is specifically used for:

[0086] The center value of the high-frequency fluctuation area of ​​residential load is selected as the node load.

[0087] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, which can take the form of a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email sending and receiving device, game console, tablet computer, wearable device, or any combination of these devices.

[0088] In a typical configuration, a computer includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0089] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0090] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0091] For any other form of computer-readable medium (or computer-readable storage medium) as described above, computer instructions may be stored thereon, which, when executed by a processor, implement one or more of the above embodiments, thereby realizing the technical solution of the present invention.

[0092] The present invention also proposes a computer program that, when executed by a processor, implements one or more of the embodiments described above, thereby realizing the technical solution of the present invention. This computer program may be specifically recorded on the above-described or other computer-readable media, and the present invention does not impose any limitations on this.

[0093] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0094] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0095] The terminology used in one or more embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in one or more embodiments of the invention and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0096] It should be understood that although the terms first, second, third, etc., may be used to describe various information in one or more embodiments of the present invention, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of one or more embodiments of the present invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0097] The above description is merely a preferred embodiment of one or more embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of the present invention should be included within the protection scope of one or more embodiments of the present invention.

Claims

1. A method for suppressing voltage exceedances in distribution networks based on photovoltaic dynamic output ratio sensing, characterized in that, The method includes: In response to the acquired power grid data of each node and line in the distribution network, DC power flow analysis is performed on the power grid data, and the active power output-voltage droop coefficient of each photovoltaic node in the distribution network is determined based on the analysis results. The output voltage and output current of each photovoltaic module in the distribution network are acquired, and the output voltage and output current are input into a pre-constructed dynamic output ratio sensing model to determine the dynamic photovoltaic output ratio output by the sensing model as a DC-side stress parameter; the dynamic output ratio sensing model is as follows: Where, η PV The dynamic photovoltaic output ratio is used to characterize the ratio of the actual output active power of a photovoltaic module to the maximum output active power. 'a' represents the first-order linear coefficient of the fitted graph, 'b' represents the linear intercept of the fitted graph, and U... pv For the output voltage, I pv Let dI be the output current. pv dU represents the change in photovoltaic current. pv This represents the change in photovoltaic voltage. The voltage of each photovoltaic grid-connected point in the distribution network is obtained and input into the active power output-voltage droop controller constructed based on the active power output-voltage droop coefficient, so that the output of the active power output-voltage droop controller is determined as the AC side stress parameter. The DC-side stress parameter is used as the outer loop controlled variable of the outer loop control loop of the distribution network, and the AC-side stress parameter is used as the outer loop control variable of the outer loop control loop. The grid-connected current d-axis reference value of the distribution network is used as the outer loop output parameter to suppress voltage over-limit of the distribution network.

2. The method according to claim 1, characterized in that, The process of performing DC power flow analysis on the power grid data and determining the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results includes: The distribution network model constructed based on the power grid data is analyzed to establish the Jacobian impedance matrix of the entire network; The correlation between voltage change and photovoltaic output ratio change is determined based on the full network Jacobian impedance matrix, and the active power output-voltage droop coefficient is tuned based on the correlation.

3. The method according to claim 1, characterized in that, The dynamic photovoltaic power ratio output by the dynamic power ratio sensing model is limited to a range of 0.75 to 1.

4. The method according to claim 1, characterized in that, The control circuit of the distribution network is a PI dual-loop control circuit, and the inner loop of the PI dual-loop control circuit is a grid-connected side current control circuit. The method further includes: The grid-connected current dq-axis current of the distribution network is used as the inner loop controlled variable, the grid-connected current d-axis reference value is used as the inner loop control variable, and the switching sequence and switching time of the converter of the distribution network are used as the inner loop output parameters.

5. The method according to claim 1, characterized in that, The DC power flow analysis of the power grid data includes: In the process of DC power flow analysis, the effect of the imaginary part of the power flow on voltage is reduced.

6. The method according to claim 1, characterized in that, The determination of the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results includes: The center value of the high-frequency fluctuation area of ​​residential load is selected as the node load.

7. A distribution network voltage over-limit suppression device based on photovoltaic dynamic output ratio sensing, characterized in that, The device includes: Analysis unit: In response to the acquired power grid data of each node and line in the distribution network, performs DC power flow analysis on the power grid data, and determines the active power output-voltage droop coefficient of each photovoltaic node in the distribution network based on the analysis results; First acquisition unit: acquires the output voltage and output current of each photovoltaic module in the distribution network, and inputs the output voltage and output current into a pre-constructed dynamic output ratio sensing model, so as to determine the dynamic photovoltaic output ratio output by the sensing model as the DC side stress parameter; The second acquisition unit acquires the voltage of each photovoltaic grid-connected point in the distribution network and inputs it into the active power output-voltage droop controller constructed based on the active power output-voltage droop coefficient, so that the output of the active power output-voltage droop controller is determined as the AC side stress parameter; the dynamic output ratio sensing model is: Where, η PV The dynamic photovoltaic output ratio is used to characterize the ratio of the actual output active power of a photovoltaic module to the maximum output active power. 'a' represents the first-order linear coefficient of the fitted graph, 'b' represents the linear intercept of the fitted graph, and U... pv For the output voltage, I pv Let dI be the output current. pv dU represents the change in photovoltaic current. pv This represents the change in photovoltaic voltage. Control unit: The DC-side stress parameter is used as the outer loop controlled variable of the outer loop control loop of the distribution network, and the AC-side stress parameter is used as the outer loop control variable of the outer loop control loop. The grid-connected current d-axis reference value of the distribution network is used as the outer loop output parameter to suppress voltage over-limit of the distribution network.

8. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor implements the steps of the method as described in any one of claims 1-6 by running the executable instructions.

9. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by the processor, this instruction implements the steps of the method as described in any one of claims 1-6.

Images