Power distribution network voltage out-of-limit suppression method, device and equipment based on photovoltaic dynamic output ratio perception and storage medium

Abstract

The invention discloses a power distribution network voltage out-of-limit suppression method, device and equipment based on photovoltaic dynamic output ratio perception and a storage medium, and the method comprises the steps: carrying out the DC power flow analysis of power grid data, and determining the active output-voltage droop coefficient of each photovoltaic node in a power distribution network according to an analysis result; acquiring output voltage and output current of each photovoltaic module in the power distribution network, and inputting the output voltage and the output current into a pre-constructed dynamic output ratio sensing model to determine the output voltage and the output current as direct current side stress parameters; obtaining the voltage of each photovoltaic grid-connected point in the power distribution network, and inputting the voltage into an active output-voltage droop controller constructed based on an active output-voltage droop coefficient to determine the voltage as an AC side stress parameter; and taking the direct current side stress parameter as an outer ring controlled quantity of an outer ring control loop of the power distribution network, and taking the alternating current side stress parameter as outer ring control of the outer ring control loop, so as to carry out voltage out-of-limit suppression on the power distribution network.

Description

Technical Field

[0001] The present invention belongs to the field of distribution network, and relates to a voltage over-limit suppression method, and in particular to a distribution network voltage over-limit suppression method, device, equipment and storage medium based on photovoltaic dynamic output ratio perception. Background Art

[0002] With the rapid growth of household distributed photovoltaics, high-penetration photovoltaic low-voltage distribution networks have become the norm for power supply networks. High-penetration photovoltaics cannot be locally absorbed in low-voltage distribution networks, which can easily lead to reverse power flow in the power grid, and then cause the voltage of the terminal power supply system to exceed the safety threshold and form a voltage over-limit phenomenon.

[0003] The current research object of voltage over-limit suppression is medium and high voltage distribution network, and the control strategies include centralized power control, energy storage coordinated control, on-load tap changer control, decentralized power control, etc. Centralized voltage control requires real-time monitoring of global distribution network parameters, which is costly and has strict communication requirements. Most low-voltage distribution networks have poor communication conditions and do not have the conditions to implement this control strategy. In comparison, decentralized voltage control only needs to perform local or block control according to the set control logic, and the construction cost is low, while the operation control is stable and reliable.

[0004] In the relevant technology, since the R / X ratio of the medium and high voltage distribution network is much smaller than that of the low voltage distribution network, the reactive power voltage regulation effect is much smaller than the active power regulation. This leads to the traditional distributed active power regulation being unable to achieve uniform reduction of photovoltaic output power in the distribution network during voltage regulation in the absence of communication, which will cause an imbalance in the income and expenditure ratio between distributed photovoltaic entities in different household distributions. 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 a distribution network based on photovoltaic dynamic output ratio perception, which can solve the deficiencies existing in the related art.

[0006] To achieve the above purpose, the present invention discloses the following technical solutions:

[0007] According to a first aspect of the present invention, a method for suppressing voltage over-limit in a distribution network based on photovoltaic dynamic output ratio perception is proposed, the method comprising:

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

[0009] Obtaining the output voltage and output current of each photovoltaic module in the distribution network, and inputting the output voltage and output current into a pre-built dynamic output ratio perception model, so as to determine the dynamic photovoltaic output ratio output by the perception model as a DC side stress parameter;

[0010] Acquire the voltage of each photovoltaic grid-connected point in the distribution network, and input it into an active output-voltage droop controller constructed based on the active output-voltage droop coefficient, so as to determine the output of the active output-voltage droop controller as an 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 of 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 perception is proposed, the device comprising:

[0013] An analysis unit: in response to the acquired grid data of each node and line in the distribution network, performing a DC power flow analysis on the grid data, and determining the active output-voltage droop coefficient of each photovoltaic node in the distribution network according to the analysis result;

[0014] A 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-built dynamic output ratio perception model, so as to determine the dynamic photovoltaic output ratio output by the perception model as a DC side stress parameter;

[0015] A second acquisition unit: acquiring the voltage of each photovoltaic grid-connected point in the distribution network, and inputting the voltage into an active output-voltage droop controller constructed based on the active output-voltage droop coefficient, so as to determine the output of the active output-voltage droop controller as an AC side stress parameter;

[0016] A control unit: uses the DC side stress parameter as an outer loop controlled variable of an outer loop control loop of the distribution network, and uses the AC side stress parameter as an outer loop control of the outer loop control loop, so as 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] a memory for storing processor-executable instructions;

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

[0021] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which computer instructions are stored, and when the instructions are executed by a processor, the steps of the method described in the first aspect are implemented.

[0022] It can be seen from the above technical solutions that the method for suppressing voltage over-limit in the distribution network based on photovoltaic dynamic output ratio perception disclosed by the present invention requires data that is relatively easy to obtain, so it has less communication requirements, can operate in a low communication environment, and is easy to transplant and has low construction costs. In addition, by suppressing the voltage over-limit of the distribution network through the output of the active output-voltage droop controller and the perception model, the photovoltaic output can be reduced in a fair and equal proportion, thereby avoiding the problem of imbalance in the revenue and expenditure ratio between distributed photovoltaic entities with different household distributions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flowchart of a method for suppressing voltage over-limit in a distribution network based on photovoltaic dynamic output ratio perception, provided by an exemplary embodiment.

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

[0025] Figure 3 It is a schematic diagram of a photovoltaic output ratio provided by an exemplary embodiment.

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

[0027] Figure 5 A block diagram of a distribution network voltage over-limit suppression device based on photovoltaic dynamic output ratio perception is provided by an exemplary embodiment. DETAILED DESCRIPTION

[0028] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of the present invention. Instead, they are merely examples of devices 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: in other embodiments, the steps of the corresponding method are not necessarily performed in the order shown and described in the present invention. In some other embodiments, the steps included in the method may be more or less than those described in the present invention. In addition, a single step described in the present invention may be decomposed into multiple steps for description in other embodiments; and multiple steps described in the present invention may be combined into a single step for description in other embodiments.

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

[0031] With the rapid growth of household distributed photovoltaics, high-penetration photovoltaic low-voltage distribution networks have become the norm for power supply networks. High-penetration photovoltaics cannot be locally absorbed in low-voltage distribution networks, which can easily lead to reverse power flow in the power grid, and then cause the voltage of the terminal power supply system to exceed the safety threshold and form a voltage over-limit phenomenon.

[0032] The current research object of voltage over-limit suppression is medium and high voltage distribution network, and the control strategies include centralized power control, energy storage coordinated control, on-load tap changer control, decentralized power control, etc. Centralized voltage control requires real-time monitoring of global distribution network parameters, which is costly and has strict communication requirements. Most low-voltage distribution networks have poor communication conditions and do not have the conditions to implement this control strategy. In comparison, decentralized voltage control only needs to perform local or block control according to the set control logic, and the construction cost is low, while the operation control is stable and reliable.

[0033] In the relevant technology, since the R / X ratio of the medium and high voltage distribution network is much smaller than that of the low voltage distribution network, the reactive power voltage regulation effect is much smaller than the active power regulation. This leads to the traditional distributed active power regulation being unable to achieve uniform reduction of photovoltaic output power in the distribution network during voltage regulation in the absence of communication, which will cause an imbalance in the income and expenditure ratio between distributed photovoltaic entities in different household distributions.

[0034] In order to solve the deficiencies existing in the related art, the present invention proposes a method for suppressing voltage over-limit in a distribution network based on photovoltaic dynamic output ratio perception.

[0035] Figure 1 FIG. 1 is a flowchart of a method for suppressing voltage over-limit in a distribution network based on photovoltaic dynamic output ratio perception provided by an exemplary embodiment. Figure 1 As shown, the method may include the following steps:

[0036] Step 102, in response to the acquired grid data of each node and line in the distribution network, performing a DC power flow analysis on the grid data, and determining the active output-voltage droop coefficient of each photovoltaic node in the distribution network according to the analysis result.

[0037] The distribution network is an important part of the power system. It is responsible for reducing the voltage of high-voltage electricity sent from the transmission network and distributing it to various power users. Photovoltaic nodes refer to specific points in the distribution network that are connected to photovoltaic power generation systems. Photovoltaic power generation systems usually include solar panels, inverters and other necessary components, which convert solar energy into electrical energy and feed it into the distribution network through this node. Non-photovoltaic nodes refer to all other nodes in the distribution network that are not connected to the photovoltaic power generation system. These nodes may be connected to traditional power generation resources (such as thermal power generation, hydropower generation, etc.) or simply other connection points in the distribution network.

[0038] DC power flow analysis is a basic tool in power system analysis, mainly used to evaluate the operation of power systems under steady-state conditions. The main analysis steps include: Establishing a network model: Determine the types of all nodes (load nodes, generator nodes, balancing nodes), determine the parameters of all branches, including resistance, reactance and transformer ratio; Forming a node admittance matrix: Use branch parameters to form a node admittance matrix (Y-Bus matrix); Select a reference node: Usually a balancing node is selected as the reference node, and its voltage phase angle is set to 0; Establish a power equation: For each node, establish an active power equation according to its type (load node, generator node); Solve a system of equations: Form an equation system about the node voltage phase angle and solve the equation system; Calculate branch power and voltage: Use the obtained voltage phase angle to calculate the active power of each branch and the voltage of each node; Analyze the results: Check the load of each branch to ensure that it does not exceed the thermal limit, and check whether the node voltage is within the allowable range.

[0039] In one embodiment, the DC power flow analysis is performed on the power grid data, and the active output-voltage droop coefficient of each photovoltaic node in the distribution network is determined according to the analysis results, including: parsing the distribution network model constructed based on the power grid data to establish a Jacobian impedance matrix of the entire network; determining the correlation between voltage changes and photovoltaic output ratio changes according to the Jacobian impedance matrix of the entire network, and adjusting the active output-voltage droop coefficient according to the correlation.

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

[0041] The model of the low-voltage distribution network is analyzed, and the relationship between the node voltages is as follows:

[0042]

[0043] Among them, U m is the voltage at node m of a single line; U m+1 is the voltage at node m+1 of a single line; P kInject active power into a certain node; Q k Inject reactive power into a node; R m is the line resistance at nodes m and m+1 of a single line; Q m is 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] Among them, ΔU is the change of voltage amplitude at each node; Δθ is the change of phase at each node; B is the Jacobian matrix of network voltage and power change; ΔP is the change of active power at each node; ΔQ is the change of reactive power at each node.

[0047] The high R / X ratio of the low voltage distribution network leads to the low interaction of Δθ and ΔQ, which further confirms the strong correlation of ΔU / ΔP.

[0048] The main change of ΔP is the active output of the photovoltaic module, so it can be further derived as the correlation between voltage change and photovoltaic output ratio change ΔU / Δη PV , to achieve the setting of photovoltaic output ratio-voltage droop coefficient.

[0049] The voltage-active power ratio droop controller can be constructed based on the above droop coefficient, that is:

[0050] η PV * =1+m(UU min );

[0051] Among them, η PV * is the reference value of photovoltaic output ratio, m is the photovoltaic output ratio-voltage droop coefficient, U is the voltage at the current node connected to the grid, and U min The downstream voltage is suppressed when the current node voltage exceeds the limit.

[0052] Step 104, obtaining the output voltage and output current of each photovoltaic component in the distribution network, and inputting the output voltage and output current into a pre-built dynamic output ratio perception model to determine the dynamic photovoltaic output ratio output by the perception model as a DC side stress parameter.

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

[0054]

[0055] Among them, η PVis the dynamic photovoltaic output ratio, which is used to characterize the ratio of the actual active power output of the photovoltaic module to the current maximum active power output, a is the first-order linear coefficient of the fitting, b is the linear intercept of the fitting, and U pv is the output voltage, I pv is the output current, dI pv is the photovoltaic current change value, dU pv is the photovoltaic voltage change value.

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

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

[0058] Step 108: Using the DC side stress parameter as an outer loop controlled variable of an outer loop control loop of the distribution network, and using the AC side stress parameter as an 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 voltage over-limit suppression method of the distribution network based on the perception of the photovoltaic dynamic output ratio is relatively easy to obtain, so its communication requirements are relatively small, it can be operated in a low communication environment, and it is easy to transplant and has low construction costs. In addition, the voltage over-limit of the distribution network is suppressed by the output of the active output-voltage droop controller and the perception model, so that the photovoltaic output can be fairly and proportionally reduced, thereby avoiding the problem of imbalance in the revenue and expenditure ratio between distributed photovoltaic entities with different household distributions.

[0060] In one embodiment, the control loop of the distribution network is a PI dual-loop control loop, the inner control loop of the PI dual-loop control loop is a grid-connected current control loop, and 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 quantity, and using the grid-connected current d-axis reference value as the inner loop control quantity, and using the switch tube conduction sequence and conduction time of the converter of the distribution network as the inner loop output parameters.

[0061] like Figure 2 As shown, the photovoltaic grid-connected architecture of the present invention is a DC / AC single-stage topology, and the photovoltaic output voltage U pv Real-time acquisition, photovoltaic output current I pv Real-time acquisition, grid-connected current I of AC filter inductor g, voltage U g The data is collected in real time, and the conduction sequence and conduction time of the switch tubes of the converter are controlled after the voltage over-limit suppression method of the present invention.

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

[0063] The real-time data of the DC side is output through the dynamic output ratio perception model to output the current perceived photovoltaic output ratio η PV The PV output ratio is not the actual PV module dynamic output ratio, but the dynamic output ratio predicted by two parameter fitting. Figure 3 Can express the difference between the above two parameters, where η PV,X Indicates the photovoltaic output voltage U pv and photovoltaic output current I pv The dynamic output ratio predicted by the dynamic output ratio perception model, Δη PV It represents the difference between the actual dynamic output ratio of the photovoltaic module and the dynamic output ratio predicted by the fitting. It can be analyzed that the dynamic output ratio perception model prediction value and the actual dynamic output ratio of the photovoltaic module are when the photovoltaic module reaches the maximum output (i.e., η PV The value is 1) perfectly coincides with the actual value and is not affected by the irradiance. At the same time, as the predicted value decreases under the same irradiance, the deviation from the actual value gradually increases, so it is necessary to select a suitable perceptual prediction range.

[0064] In one embodiment, the active output-voltage droop coefficient of each photovoltaic node in the distribution network is determined based on the analysis results, including: 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 perception model can be upgraded or segmented according to the fitting effect, with the purpose of reducing the fitting error to expand the effective control range.

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

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

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

[0069] The analysis unit 502 is used to perform a DC power flow analysis on the grid data in response to the acquired grid data of each node and line in the distribution network, and determine the active output-voltage droop coefficient of each photovoltaic node in the distribution network according to the analysis result;

[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-built dynamic output ratio perception model to determine the dynamic photovoltaic output ratio output by the perception model as a DC side stress parameter;

[0071] A second acquisition unit 506 is used to acquire the voltage of each photovoltaic grid-connected point in the distribution network, and input it into an active output-voltage droop controller constructed based on the active output-voltage droop coefficient, so as to determine the output of the active output-voltage droop controller as an 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 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 configured to:

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

[0075] The correlation between the voltage change and the photovoltaic output ratio change is determined according to the full network Jacobian impedance matrix, and the active output-voltage droop coefficient is adjusted according to the correlation.

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

[0077]

[0078] Among them, η PV is the dynamic photovoltaic output ratio, which is used to characterize the ratio of the actual output active power of the photovoltaic module to the current maximum output active power. a is the first-order linear coefficient of the fitting, b is the linear intercept of the fitting, and U pv is the output voltage, I pv is the output current, dI pv is the photovoltaic current change value, dU pv is the photovoltaic voltage change value.

[0079] Optionally, the limit range of the dynamic photovoltaic output ratio output by the dynamic output ratio perception model is 0.75 to 1.

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

[0081] An outer loop output unit 510, used to use the grid-connected current d-axis reference value of the distribution network as an outer loop output parameter;

[0082] The inner loop control unit 512 is used to use the dq-axis current of the distribution network as the inner loop controlled variable, the d-axis reference value of the grid current as the inner loop controlled variable, and the conduction sequence and conduction time of the switch tubes of the converter of the distribution network as the inner loop output parameters.

[0083] Optionally, the analysis unit 502 is specifically configured to:

[0084] During DC power flow analysis, reduce the effect of the imaginary part of the power flow on the voltage.

[0085] Optionally, the first acquiring unit 504 is specifically configured to:

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

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

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

[0089] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0090] Computer-readable media include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. Information can be computer-readable instructions, data structures, program modules 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 technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0091] With respect to the computer-readable medium (or computer-readable storage medium) as described above or in any other form, computer instructions may be stored thereon, and when the instructions are executed by a processor, one or more of the above-mentioned embodiments are implemented, thereby realizing the technical solution of the present invention.

[0092] The present invention also proposes a computer program, which, when executed by a processor, implements one or more of the above embodiments, thereby realizing the technical solution of the present invention. The computer program may be specifically recorded in the above or any other form of computer-readable medium, and the present invention is not limited thereto.

[0093] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0094] The above describes specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0095] The terms used in one or more embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of the present invention. The singular forms of "a", "said" and "the" used in one or more embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" 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, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

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

Claims

1. A method for suppressing voltage over-limit in a distribution network based on photovoltaic dynamic output ratio perception, characterized in that: The method comprises: In response to the acquired grid data of each node and line in the distribution network, a DC power flow analysis is performed on the grid data, and an active output-voltage droop coefficient of each photovoltaic node in the distribution network is determined according to the analysis result; Obtaining the output voltage and output current of each photovoltaic module in the distribution network, and inputting the output voltage and output current into a pre-built dynamic output ratio perception model, so as to determine the dynamic photovoltaic output ratio output by the perception model as a DC side stress parameter; Acquire the voltage of each photovoltaic grid-connected point in the distribution network, and input it into an active output-voltage droop controller constructed based on the active output-voltage droop coefficient, so as to determine the output of the active output-voltage droop controller as an 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 of the outer loop control loop to suppress voltage over-limit of the distribution network.

2. The method according to claim 1, characterized in that The DC power flow analysis is performed on the power grid data, and the active output-voltage droop coefficient of each photovoltaic node in the distribution network is determined according to the analysis result, including: Analyzing the distribution network model constructed based on the power grid data to establish a Jacobian impedance matrix of the entire network; The correlation between the voltage change and the photovoltaic output ratio change is determined according to the full network Jacobian impedance matrix, and the active output-voltage droop coefficient is adjusted according to the correlation.

3. The method according to claim 1, characterized in that The dynamic output ratio perception model is: Among them, η PV is the dynamic photovoltaic output ratio, which is used to characterize the ratio of the actual output active power of the photovoltaic module to the current maximum output active power. a is the first-order linear coefficient of the fitting, b is the linear intercept of the fitting, and U pv is the output voltage, I pv is the output current, dI pv is the photovoltaic current change value, dU pv is the photovoltaic voltage change value.

4. The method according to claim 3, characterized in that The limit range of the dynamic photovoltaic output ratio output by the dynamic output ratio perception model is 0.75 to 1.

5. The method according to claim 1, characterized in that The control loop of the distribution network is a PI double-loop control loop, the inner loop control loop of the PI double-loop control loop is a grid-connected current control loop, and the method further includes: Taking the grid-connected current d-axis reference value of the distribution network as the outer loop output parameter; 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 controlled variable, and the switch tube conduction sequence and conduction time of the converter of the distribution network are used as the inner loop output parameters.

6. The method according to claim 1, characterized in that The performing DC power flow analysis on the power grid data includes: During DC power flow analysis, reduce the effect of the imaginary part of the power flow on the voltage.

7. The method according to claim 1, characterized in that The step of determining the active output-voltage droop coefficient of each photovoltaic node in the distribution network according to the analysis result includes: The center value of the high-frequency fluctuation area of ​​resident load is selected as the node load.

8. A distribution network voltage over-limit suppression device based on photovoltaic dynamic output ratio perception, characterized in that: The device comprises: An analysis unit: in response to the acquired grid data of each node and line in the distribution network, performing a DC power flow analysis on the grid data, and determining the active output-voltage droop coefficient of each photovoltaic node in the distribution network according to the analysis result; A 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-built dynamic output ratio perception model, so as to determine the dynamic photovoltaic output ratio output by the perception model as a DC side stress parameter; A second acquisition unit: acquiring the voltage of each photovoltaic grid-connected point in the distribution network, and inputting the voltage into an active output-voltage droop controller constructed based on the active output-voltage droop coefficient, so as to determine the output of the active output-voltage droop controller as an AC side stress parameter; A control unit: uses the DC side stress parameter as an outer loop controlled variable of an outer loop control loop of the distribution network, and uses the AC side stress parameter as an outer loop control of the outer loop control loop, so as to suppress voltage over-limit of the distribution network.

9. An electronic device, characterized in that: include: processor; a memory for storing processor-executable instructions; The processor implements the steps of the method according to any one of claims 1 to 7 by running the executable instructions.

10. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the instruction 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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