Short-circuit ratio-aware method for configuring capacity of grid-connected photovoltaic cluster units

Abstract

The application relates to the technical field of alternating current power grids, and particularly discloses a short-circuit ratio sensing-based capacity configuration method for grid-following and grid-forming photovoltaic cluster units, which comprises the following steps: acquiring the short-circuit ratio value of a grid-connected access point in a target distribution network, the output power and voltage of a photovoltaic cluster, and interference measurement values; adaptively adjusting inverters in the photovoltaic cluster to obtain preliminary control instructions; determining the proportion of the operation modes of the photovoltaic cluster to obtain mode switching instructions and capacity allocation schemes; adjusting the active and reactive output set values of the inverters in the photovoltaic cluster to coordinate the outputs of the inverters in the photovoltaic cluster and respond to the frequency and voltage changes of the target distribution network, thereby obtaining collaborative control instructions; fusing the preliminary control instructions, the output set values and the collaborative control instructions to obtain a comprehensive control instruction set, and delivering the comprehensive control instruction set to the inverters in the photovoltaic cluster; and the application can improve the capacity configuration efficiency of the grid-following and grid-forming photovoltaic cluster units.

Description

Technical Field

[0001] This invention relates to the field of AC power grid technology, and in particular to a method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing. Background Technology

[0002] In the field of AC power grid technology, grid-connected operation of photovoltaic clusters has become an important form of new energy consumption. The mainstream configuration method is to simultaneously configure grid-connected and grid-connected inverters in photovoltaic clusters. However, the existing capacity configuration methods for photovoltaic cluster units do not take the short-circuit ratio at the grid connection point as a core sensing parameter. They cannot dynamically adjust the ratio of the two types of inverter operation modes and capacity allocation schemes according to the grid connection intensity. Furthermore, during the inverter control command generation stage, the output response is not adaptively adjusted by combining the interference measurement values ​​of sunlight and voltage fluctuations. This results in a large deviation between the actual output of the inverter and the expected response, which directly reduces the adaptability of capacity configuration and control commands.

[0003] Existing technologies lack deep coupling between the active and reactive power output setpoint adjustment of photovoltaic cluster inverters and mode switching commands and capacity allocation schemes. Capacity quota splitting and constraint allocation lack standardized processes. At the same time, when coordinating inverter output, they fail to effectively aggregate the cluster's power output status and accurately respond to frequency and voltage changes in the distribution network. Furthermore, the fusion of various control commands is merely a simple superposition without semantic alignment and timing arbitration of execution conflicts, which easily leads to command execution contradictions. This results in low capacity configuration efficiency of photovoltaic cluster units, poor output coordination between inverters, difficulty in adapting to the dynamic operating state of the distribution network, and inability to guarantee the stable operation of photovoltaic clusters after grid connection. Summary of the Invention

[0004] This invention provides a method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing, in order to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing, comprising: Step 1: Integrate the short-circuit ratio of the grid connection point in the target distribution network, the output power and voltage of the photovoltaic cluster, and the interference measurement values ​​characterizing the fluctuations in light and voltage into the real-time operating data of the target distribution network; Step 2: Based on the measured interference value and the preset inverter reference parameters, adaptively adjust the actual output response and expected response of the inverter in the photovoltaic cluster to obtain the initial control command of the inverter; Step 3: Based on the short-circuit ratio, determine the operating mode ratio of the grid-connected inverters and the grid-following inverters in the photovoltaic cluster, and obtain the mode switching command and capacity allocation scheme of the photovoltaic cluster. Step 4: Adjust the active and reactive power output settings of the inverters in the photovoltaic cluster according to the mode switching command and the capacity allocation scheme; Step 5: Based on the adjusted active and reactive power output settings, coordinate the output between inverters in the photovoltaic cluster and respond to the frequency and voltage changes of the target distribution network to obtain the coordinated control command of the target distribution network; Step 6: Integrate the preliminary control command, the output setpoint, and the collaborative control command to obtain the comprehensive control command set of the target distribution network, and send it to the inverters in the photovoltaic cluster.

[0006] In a preferred embodiment, the integration of the short-circuit ratio at the grid connection point in the target distribution network, the output power and voltage of the photovoltaic cluster, and interference measurements characterizing irradiance and voltage fluctuations into real-time operating data of the target distribution network includes: By using the synchronous phasor measurement unit at the grid connection point in the target distribution network, the voltage phasor and current phasor of the grid connection point are collected to generate the short-circuit capacity of the grid connection point. Extract the short-circuit ratio of the grid connection point from the short-circuit capacity; The local controller of the inverter in the photovoltaic cluster in the target distribution network reads the real-time output active power, real-time output reactive power and grid-connected voltage amplitude of the inverter, and aggregates them into the output power and voltage of the photovoltaic cluster. The system obtains the sampled values ​​of solar irradiance in the area where the photovoltaic cluster is located under a continuous time series, and obtains the sampled values ​​of instantaneous voltage under a synchronous time series from the voltage monitoring device at the grid connection point. The sampled values ​​of light irradiance and the sampled values ​​of instantaneous voltage are correlated to form an interference measurement value characterizing the fluctuations in light and voltage; Using a unified timestamp identifier, the short-circuit ratio, the output power and voltage, and the interference measurement values ​​are recombined to obtain the real-time operating data of the target distribution network.

[0007] In a preferred embodiment, the step of adaptively adjusting the actual output response and expected response of the inverter in the photovoltaic cluster based on the interference measurement value and preset inverter reference parameters to obtain the initial control command of the inverter includes: Read the actual active and reactive power output of the inverter in the photovoltaic cluster during the current control cycle to obtain the actual output response of the inverter. The sampled values ​​of light irradiance and instantaneous voltage in the interference measurement are mapped and matched with the preset inverter reference parameters to obtain the expected active power reference value and the expected reactive power reference value of the inverter. The expected active power reference value and the expected reactive power reference value are correlated to form the expected response of the inverter; The actual output response is compared with the expected response point by point to generate the active power deviation indication and reactive power deviation indication of the inverter. Based on the active power deviation indication and the reactive power deviation indication, adjust the active axis reference value and the reactive axis reference value of the inverter's inner current loop so that the actual output response approaches the expected response. The adjusted active axis reference value and reactive axis reference value of the inner current loop are formatted and encapsulated to obtain the initial control command of the inverter.

[0008] In a preferred embodiment, the step of determining the operating mode ratio of grid-connected inverters and grid-linked inverters in the photovoltaic cluster based on the short-circuit ratio, to obtain the mode switching command and capacity allocation scheme of the photovoltaic cluster, includes: The grid connection strength attribute of the grid connection access point is obtained by interpreting the short-circuit ratio. Based on the grid connection strength attribute, mode tendency is extracted from the preset inverter operation mode library to obtain the cluster operation mode tendency of the photovoltaic cluster. The cluster operation mode tendency includes the activation ratio of grid-connected inverters and grid-following inverters. Based on the cluster's operating mode preference, the inverters in the photovoltaic cluster that are in standby mode are assigned operating modes to obtain the mode identifiers of the inverters. Based on the mode identifier, the rated capacity of inverters assigned with grid-connected operation mode identifiers is aggregated for grid-connected capacity, and the rated capacity of inverters assigned with grid-following operation mode identifiers is aggregated for grid-following capacity, so as to obtain the total capacity of grid-connected units and the total capacity of grid-following units in the photovoltaic cluster. Based on the total capacity of the grid-connected units and the total capacity of the grid-following units, the capacity allocation ratio of the photovoltaic cluster is proportionally adjusted to obtain the capacity allocation scheme of the photovoltaic cluster, and the mode identifier of the inverter is encapsulated into the corresponding mode switching instruction.

[0009] In a preferred embodiment, based on the grid connection strength attribute, a mode preference extraction is performed on a preset inverter operation mode library to obtain the cluster operation mode preference of the photovoltaic cluster. The cluster operation mode preference includes the activation ratio of grid-connected inverters and grid-following inverters, including: The grid connection strength attribute is interpreted to obtain the grid connection strength level of the grid connection access point; Based on the grid connection strength level, the attenuation coefficient and reference threshold are extracted from the preset inverter operation mode library to obtain the mode tendency tuning parameters of the photovoltaic cluster. Based on the grid connection strength level, the inverter operation mode library is filtered by mode domain to obtain the candidate modes of the photovoltaic cluster; Based on the grid connection strength level and the mode preference tuning parameters, the operating mode preference assessment is performed on the candidate modes to obtain the preference weight of the candidate modes. The formula for calculating the preference weight is as follows: ; In the formula, This represents the bias weight. Represents the natural constant. This represents the attenuation coefficient. This indicates the grid connection strength level. This represents the reference threshold; Based on the aforementioned bias weights, the activation ratio of the grid-connected operation mode and the grid-following operation mode in the candidate modes is adjusted to obtain the activation ratio of the grid-connected inverter and the grid-following inverter. The activation ratio is encapsulated with a mode preference to obtain the cluster operation mode preference of the photovoltaic cluster.

[0010] In a preferred embodiment, the step of aggregating the rated capacity of inverters assigned with grid-connected operation mode identifiers and aggregating the rated capacity of inverters assigned with grid-following operation mode identifiers to obtain the total capacity of grid-connected units and the total capacity of grid-following units in the photovoltaic cluster, based on the mode identifiers, includes: The mode identifier and corresponding rated capacity of the inverter in the photovoltaic cluster are associated and mapped to obtain the mode capacity association tuple of the inverter; Based on the aforementioned mode capacity association tuple, the rated capacity of inverters with mode identifiers of grid-connected operation mode is aggregated to obtain the total capacity of the grid-connected units of the photovoltaic cluster. Based on the aforementioned mode capacity association tuple, the rated capacity of inverters with the mode identifier set to grid-connected operation mode is encapsulated for capacity matching to obtain the total capacity of the grid-connected units in the photovoltaic cluster.

[0011] In a preferred embodiment, adjusting the active and reactive power output settings of the inverters in the photovoltaic cluster according to the mode switching command and the capacity allocation scheme includes: The mode switching command is parsed to obtain the inverter's operating mode assignment identifier; The capacity allocation scheme is decomposed into capacity quotas to obtain the active capacity quota and reactive capacity quota of the inverter. Based on the operating mode assignment identifier, the active power output setpoint of the inverter is adaptively tuned to obtain the mode-based active power setpoint of the inverter. Based on the active capacity quota and the reactive capacity quota, capacity constraint allocation is performed on the patterned active capacity setting value and the reactive output setting value of the inverter to obtain the capacity constraint active capacity setting value and the capacity constraint reactive capacity setting value of the inverter. The capacity-constrained active power setting value and the capacity-constrained reactive power setting value are associated as the active and reactive power output setting values ​​of the inverter in the photovoltaic cluster.

[0012] In a preferred embodiment, the step of adjusting the modemed active power setpoint and the inverter's reactive power output setpoint based on the active power capacity quota and the reactive power capacity quota to obtain the inverter's capacity-constrained active power setpoint and capacity-constrained reactive power setpoint includes: The active capacity quota and the reactive capacity quota are deconstructed to extract the active capacity quota component and the reactive capacity quota component of the inverter. Based on the active power quota component, the active power upper limit is checked on the patterned active power setting value to obtain the capacity constraint active power setting value of the inverter. Based on the reactive power quota component, the reactive power output setting value of the inverter is clamped by a reactive power threshold to obtain the capacity constraint reactive power setting value of the inverter. The capacity constraint active power setting value and the capacity constraint reactive power setting value are associated and encapsulated to obtain the capacity constraint setting value pair of the inverter.

[0013] In a preferred embodiment, the step of coordinating the outputs of inverters in the photovoltaic cluster based on the adjusted active and reactive power output setpoints, and responding to frequency and voltage changes in the target distribution network to obtain coordinated control commands for the target distribution network, includes: Based on the adjusted active and reactive power output settings, the real-time output margin of the inverters in the photovoltaic cluster is aggregated and mapped to obtain the cluster output capacity status of the photovoltaic cluster. The grid connection frequency of the target distribution network is perturbed and decoupled to extract the frequency offset of the target distribution network and obtain the frequency deviation characteristic quantity of the target distribution network. The grid-connected voltage of the target distribution network is analyzed for fluctuations to extract the voltage amplitude offset of the target distribution network and obtain the voltage fluctuation characteristic quantity of the target distribution network. Based on the frequency deviation characteristic and the voltage fluctuation characteristic, the power output capability status of the cluster is modulated to obtain the response modulation command of the inverter. The response modulation commands are fused and prioritized to obtain the coordinated control commands for the target distribution network.

[0014] In a preferred embodiment, the process of integrating the initial control command, the output setpoint, and the coordinated control command to obtain a comprehensive control command set for the target distribution network, and then issuing it to the inverters in the photovoltaic cluster, includes: The initial control command, the output set value, and the coordinated control command are semantically aligned to obtain the alignment command set of the target distribution network; The execution conflicts of the instructions in the alignment instruction set are arbitrated in a timing manner to obtain the timing arrangement instruction table of the target distribution network; The timing arrangement instruction table is aggregated and encapsulated to obtain the comprehensive control instruction set of the target distribution network; Based on the comprehensive control instruction set, instructions are broadcast and pushed to the control ports of the inverters in the photovoltaic cluster.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses the short-circuit ratio at the grid connection point as the core sensing parameter. It can interpret the grid connection strength and dynamically adjust the activation ratio and capacity allocation scheme of grid-connected and grid-following inverters. Combined with the measured values ​​of sunlight and voltage fluctuation interference, it adaptively adjusts the inverter output response, so that the capacity configuration is adapted to the actual grid connection strength and external interference. This greatly improves the accuracy and dynamic adaptability of photovoltaic cluster unit capacity configuration and solves the problems of lack of core sensing parameters and low configuration efficiency in traditional configuration methods.

[0016] 2. This invention achieves refined integration of multi-dimensional control commands and coordinated output control of inverters. First, it adjusts the active and reactive power setpoints based on mode switching and capacity allocation. Then, it modulates the cluster output in conjunction with grid frequency and voltage changes. Finally, it performs semantic alignment and timing arbitration on various commands to avoid command execution conflicts, effectively coordinates the output cooperation between inverters, improves the photovoltaic cluster's response capability to grid frequency and voltage fluctuations, and ensures the stability and coordination of the photovoltaic cluster's grid-connected operation. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing, according to an embodiment of the present invention. The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] This application provides a method for configuring the capacity of grid-connected photovoltaic (PV) cluster units based on short-circuit ratio awareness. The execution entity of this method includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application: a server, a terminal, etc. In other words, the method for configuring the capacity of grid-connected PV cluster units based on short-circuit ratio awareness can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster. The server can be an independent server or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms.

[0020] Reference Figure 1 The diagram shown is a flowchart illustrating a grid-connected photovoltaic cluster capacity configuration method based on short-circuit ratio sensing according to an embodiment of the present invention. In this embodiment, the grid-connected photovoltaic cluster capacity configuration method based on short-circuit ratio sensing includes: Step 1: Integrate the short-circuit ratio of the grid connection point in the target distribution network, the output power and voltage of the photovoltaic cluster, and the interference measurement values ​​characterizing the fluctuations in light and voltage into the real-time operating data of the target distribution network; In this embodiment of the invention, the integration of the short-circuit ratio at the grid connection point in the target distribution network, the output power and voltage of the photovoltaic cluster, and the interference measurements characterizing irradiance and voltage fluctuations into the real-time operating data of the target distribution network includes: By using the synchronous phasor measurement unit at the grid connection point in the target distribution network, the voltage phasor and current phasor of the grid connection point are collected to generate the short-circuit capacity of the grid connection point. Extract the short-circuit ratio of the grid connection point from the short-circuit capacity; The local controller of the inverter in the photovoltaic cluster in the target distribution network reads the real-time output active power, real-time output reactive power and grid-connected voltage amplitude of the inverter, and aggregates them into the output power and voltage of the photovoltaic cluster. The system obtains the sampled values ​​of solar irradiance in the area where the photovoltaic cluster is located under a continuous time series, and obtains the sampled values ​​of instantaneous voltage under a synchronous time series from the voltage monitoring device at the grid connection point. The sampled values ​​of light irradiance and the sampled values ​​of instantaneous voltage are correlated to form an interference measurement value characterizing the fluctuations in light and voltage; Using a unified timestamp identifier, the short-circuit ratio, the output power and voltage, and the interference measurement values ​​are recombined to obtain the real-time operating data of the target distribution network.

[0021] The synchronous phasor measurement unit is fixedly installed at the physical location of the grid connection point of the target distribution network. The unit continuously collects the electrical signals of the grid connection point at a constant timing rhythm, directly and accurately acquiring the voltage phasor data and current phasor data of the grid connection point. Then, through the electrical quantity analysis and calculation logic of the synchronous phasor measurement unit itself, the collected voltage phasors and current phasors are analyzed and calculated item by item, and finally the short-circuit capacity of the grid connection point is directly generated.

[0022] Using the short-circuit capacity of the already generated grid connection point as the basic calculation data, and following the established execution process of distribution network short-circuit characteristic analysis, all electrical characteristic information contained in the short-circuit capacity is decomposed layer by layer. Then, the core characteristic information that can directly reflect the short-circuit carrying capacity of the grid connection point is selected from the decomposed electrical characteristic information. Through direct comparison and refinement of the core characteristic information, the short-circuit ratio of the grid connection point is finally extracted.

[0023] Each inverter in the photovoltaic cluster within the target distribution network is equipped with its own dedicated local controller. Each inverter's local controller reads the real-time output active power, real-time output reactive power, and voltage amplitude at the inverter's grid connection port during operation. All inverters' local controllers stably transmit the aforementioned data to the photovoltaic cluster's dedicated data aggregation node. The data aggregation node collects and integrates all transmitted data to ultimately form the photovoltaic cluster's output power and voltage.

[0024] Dedicated solar irradiance acquisition equipment is deployed within the actual geographical area where the photovoltaic cluster is located. This solar irradiance acquisition equipment continuously performs sampling work at fixed time intervals, uninterruptedly acquiring solar irradiance sampling values ​​in the continuous time series of the area. At the same time, the voltage monitoring device at the grid connection point is activated. This voltage monitoring device maintains a sampling sequence completely consistent with that of the solar irradiance acquisition equipment, synchronously acquiring instantaneous voltage sampling values ​​in the synchronous time series.

[0025] The obtained irradiance sampling values ​​and instantaneous voltage sampling values ​​are matched point by point according to the same time node. The matched irradiance sampling data and instantaneous voltage sampling data are tightly bound together. The data formed after binding can intuitively reflect the corresponding relationship between irradiance changes and voltage fluctuations. The bound data is the interference measurement value characterizing irradiance and voltage fluctuations.

[0026] The extracted short-circuit ratio, the output power and voltage of the integrated photovoltaic cluster, and the interference measurement values ​​representing the fluctuations of light and voltage are each assigned a unified and consistent timestamp. The three sets of different types of data are accurately matched and orderly spliced ​​together by the unified timestamp, and the overall reorganization operation of the three sets of data is completed. The complete data set formed after reorganization is the real-time operation data of the target distribution network.

[0027] Step 2: Based on the measured interference value and the preset inverter reference parameters, adaptively adjust the actual output response and expected response of the inverter in the photovoltaic cluster to obtain the initial control command of the inverter. In this embodiment of the invention, the step of adaptively adjusting the actual output response and expected response of the inverter in the photovoltaic cluster based on the interference measurement value and preset inverter reference parameters to obtain the initial control command of the inverter includes: Read the actual active and reactive power output of the inverter in the photovoltaic cluster during the current control cycle to obtain the actual output response of the inverter. The sampled values ​​of light irradiance and instantaneous voltage in the interference measurement are mapped and matched with the preset inverter reference parameters to obtain the expected active power reference value and the expected reactive power reference value of the inverter. The expected active power reference value and the expected reactive power reference value are correlated to form the expected response of the inverter; The actual output response is compared with the expected response point by point to generate the active power deviation indication and reactive power deviation indication of the inverter. Based on the active power deviation indication and the reactive power deviation indication, adjust the active axis reference value and the reactive axis reference value of the inverter's inner current loop so that the actual output response approaches the expected response. The adjusted active axis reference value and reactive axis reference value of the inner current loop are formatted and encapsulated to obtain the initial control command of the inverter.

[0028] The inverter's local controller has a dedicated power acquisition channel that remains operational after the current control cycle begins. This channel directly connects to the inverter's power output port to acquire the actual active power output by the inverter during the current control cycle. Simultaneously, another independent and synchronously operating power acquisition channel acquires the actual reactive power output by the inverter during the same control cycle. The data acquired by both channels is directly transmitted to the controller's data integration module. The data integration module merges the two data streams without any missing data, and the resulting complete data is the inverter's actual output response.

[0029] The inverter control unit has pre-stored fixed inverter reference parameters. These parameters are fixed reference data adapted to the inverter's own operating characteristics. The irradiance sample value included in the interference measurement is matched item by item with the reference data of the corresponding irradiance conditions in the inverter reference parameters. At the same time, the instantaneous voltage sample value included in the interference measurement is matched item by item with the reference data of the corresponding voltage state in the inverter reference parameters. During the matching process, the predetermined standards in the reference parameters are strictly matched according to the actual state of irradiance and voltage. After the matching is completed, the target active power value that the inverter should output is directly determined. This value is the inverter's expected active power reference value. At the same time, the target reactive power value that the inverter should output is determined. This value is the inverter's expected reactive power reference value.

[0030] The obtained expected active power reference value is transmitted to the power integration unit of the inverter control logic. At the same time, the expected reactive power reference value is also transmitted to the power integration unit. The power integration unit binds and combines the two sets of reference values ​​according to the coordinated correspondence between active power and reactive power when the inverter is running normally, so that the two sets of data form a unified ideal output reference system. The complete data system after binding and combining is the expected response of the inverter.

[0031] The actual output active power in the actual output response of the inverter is directly compared with the expected active power reference value in the expected response at every data point. This clearly determines the difference between the actual output active power and the expected active power reference value. After standardization by the controller, this difference information is formed into specific indication data, which is the active power deviation indication of the inverter. At the same time, the actual output reactive power in the actual output response is directly compared with the expected reactive power reference value in the expected response at every data point. This clearly determines the difference between the actual output reactive power and the expected reactive power reference value. After standardization by the controller, this difference information is formed into specific indication data, which is the reactive power deviation indication of the inverter.

[0032] When the active power deviation indicator shows that the actual output active power deviates from the expected active power reference value, the inverter control loop directly adjusts the active axis reference value of the current inner loop. If the actual output is too high, the active axis reference value is lowered; if the actual output is too low, the active axis reference value is raised. When the reactive power deviation indicator shows that the actual output reactive power deviates from the expected reactive power reference value, the control loop directly adjusts the reactive axis reference value of the current inner loop. If the actual output is too high, the reactive axis reference value is lowered; if the actual output is too low, the reactive axis reference value is raised. The entire adjustment process continues until the actual output response of the inverter continuously approaches the expected response.

[0033] The adjusted active axis reference value and reactive axis reference value of the inner current loop are transmitted to the inverter's instruction encapsulation module. The instruction encapsulation module arranges the two sets of reference values ​​in sequence according to the standard data format that the inverter's execution unit can recognize, removes redundant information in the data, and standardizes the data transmission format and structure, so that the two sets of reference values ​​form a complete data whole that can be directly transmitted and executed. This data whole after standard arrangement and structure is the inverter's initial control instruction.

[0034] Step 3: Based on the short-circuit ratio, determine the matching ratio of the operating modes of the grid-connected inverters and the grid-following inverters in the photovoltaic cluster, and obtain the mode switching command and capacity allocation scheme of the photovoltaic cluster. In this embodiment of the invention, the step of determining the operating mode ratio of grid-connected inverters and grid-linked inverters in the photovoltaic cluster based on the short-circuit ratio, and obtaining the mode switching command and capacity allocation scheme of the photovoltaic cluster, includes: The grid connection strength attribute of the grid connection access point is obtained by interpreting the short-circuit ratio. Based on the grid connection strength attribute, mode tendency is extracted from the preset inverter operation mode library to obtain the cluster operation mode tendency of the photovoltaic cluster. The cluster operation mode tendency includes the activation ratio of grid-connected inverters and grid-following inverters. Based on the cluster's operating mode preference, the inverters in the photovoltaic cluster that are in standby mode are assigned operating modes to obtain the mode identifiers of the inverters. Based on the mode identifier, the rated capacity of inverters assigned with grid-connected operation mode identifiers is aggregated for grid-connected capacity, and the rated capacity of inverters assigned with grid-following operation mode identifiers is aggregated for grid-following capacity, so as to obtain the total capacity of grid-connected units and the total capacity of grid-following units in the photovoltaic cluster. Based on the total capacity of the grid-connected units and the total capacity of the grid-following units, the capacity allocation ratio of the photovoltaic cluster is proportionally adjusted to obtain the capacity allocation scheme of the photovoltaic cluster, and the mode identifier of the inverter is encapsulated into the corresponding mode switching instruction.

[0035] Based on the grid connection strength attribute, a mode preference extraction is performed on a preset inverter operation mode library to obtain the cluster operation mode preference of the photovoltaic cluster. The cluster operation mode preference includes the activation ratio of grid-connected inverters and grid-following inverters, including: The grid connection strength attribute is interpreted to obtain the grid connection strength level of the grid connection access point; Based on the grid connection strength level, the attenuation coefficient and reference threshold are extracted from the preset inverter operation mode library to obtain the mode tendency tuning parameters of the photovoltaic cluster. Based on the grid connection strength level, the inverter operation mode library is filtered by mode domain to obtain the candidate modes of the photovoltaic cluster; Based on the grid connection strength level and the mode preference tuning parameters, the operating mode preference assessment is performed on the candidate modes to obtain the preference weight of the candidate modes. The formula for calculating the preference weight is as follows: ; In the formula, This represents the bias weight. Represents the natural constant. This represents the attenuation coefficient. This indicates the grid connection strength level. This represents the reference threshold; Based on the aforementioned bias weights, the activation ratio of the grid-connected operation mode and the grid-following operation mode in the candidate modes is adjusted to obtain the activation ratio of the grid-connected inverter and the grid-following inverter. The activation ratio is encapsulated with a mode preference to obtain the cluster operation mode preference of the photovoltaic cluster.

[0036] Based on the mode identifier, the rated capacity of inverters assigned with grid-connected operation mode identifiers is aggregated for grid-connected capacity, and the rated capacity of inverters assigned with grid-following operation mode identifiers is aggregated for grid-following capacity, to obtain the total capacity of grid-connected units and the total capacity of grid-following units in the photovoltaic cluster, including: The mode identifier and corresponding rated capacity of the inverter in the photovoltaic cluster are associated and mapped to obtain the mode capacity association tuple of the inverter; Based on the aforementioned mode capacity association tuple, the rated capacity of inverters with mode identifiers of grid-connected operation mode is aggregated to obtain the total capacity of the grid-connected units of the photovoltaic cluster. Based on the aforementioned mode capacity association tuple, the rated capacity of inverters with the mode identifier set to grid-connected operation mode is encapsulated for capacity matching to obtain the total capacity of the grid-connected units in the photovoltaic cluster.

[0037] After the grid connection strength interpretation unit is started, it uses the short-circuit ratio as the core input data and decomposes and analyzes the grid rigidity support capability, voltage maintenance characteristics under short-circuit faults, grid inertia support level, and resistance to external disturbances reflected by the short-circuit ratio at the grid connection point. The features corresponding to the short-circuit ratio directly correspond to the strength of the grid connection support capability. The interpretation unit sorts out and integrates these decomposed qualitative grid connection support features one by one according to a fixed interpretation logic, removes duplicate information, clarifies the correlation between each feature, and finally forms attribute information that can completely and accurately characterize the support strength of the grid connection point. This attribute information is the grid connection strength attribute of the grid connection point.

[0038] The distribution network control center has pre-formulated and solidified qualitative classification rules for grid connection strength levels. These rules clearly define the judgment conditions corresponding to different grid connection strength levels, including specific requirements such as voltage support capacity range, short-circuit response speed, and grid rigidity. The analysis unit precisely compares all the contents of the grid connection strength attributes, such as voltage support capacity, short-circuit response characteristics, grid rigidity, and inertia level, with each judgment condition corresponding to each strength level in the classification rules. It verifies whether each item of the grid connection strength attribute meets the requirements of the corresponding level and finds the strength level judgment result that perfectly matches the grid connection strength attribute without any deviation. The strength level result determined by this matching is the grid connection strength level of the grid connection access point.

[0039] The inverter operation mode library is pre-classified and stored according to different grid connection intensity levels, using a hierarchical archiving method. Each grid connection intensity level corresponds to a dedicated parameter storage partition, which stores the attenuation coefficient and reference threshold adapted to the grid operation state of that level. All parameters have been pre-calibrated and fixed. Using the determined grid connection intensity level as the basis for accurate retrieval, the retrieval unit directly locates the parameter storage partition in the inverter operation mode library that corresponds exactly to that level, and directly extracts the dedicated attenuation coefficient and reference threshold from that partition. After extraction, the two parameters are arranged and combined in a fixed order, and irrelevant and redundant information is removed to form a complete parameter set. This parameter set is the mode tendency tuning parameter of the photovoltaic cluster.

[0040] The control unit first clarifies the distribution network stability operation constraints, voltage support requirements, and inertia replenishment requirements corresponding to the current grid connection intensity level. This serves as the core basis for mode selection. The control unit defines the selection range of operating modes that are compatible with the grid connection intensity level in the inverter operating mode library. Within this defined range, the selection unit checks the compatibility of each inverter operating mode in the library one by one, eliminating operating modes that cannot meet the current grid connection support requirements, do not meet the grid stability operation conditions, or cannot adapt to the voltage support requirements. Only all operating modes that can fully adapt to the grid connection intensity level and meet all operating constraints are retained. The combination of all retained operating modes is the candidate mode for the photovoltaic cluster.

[0041] The evaluation unit uses the actual support needs and stable operation requirements of the power grid reflected in the grid connection intensity level as the evaluation basis. Combined with the operation constraints limited by the attenuation coefficient and reference threshold in the mode tendency setting parameters, the unit determines the degree of adaptation for each operation mode among the candidate modes. During the determination process, the unit clarifies the operation stability, voltage regulation capability, and inertia support effect of each operation mode under the current grid connection intensity level. These determination results are transformed into characteristic information of the degree of adaptation. Then, according to a fixed transformation logic, the degree of adaptation is transformed into corresponding weight characteristic information. Each candidate mode corresponds to a unique weight information, which is the tendency weight of the candidate mode.

[0042] The attenuation coefficient used in the bias weight calculation is extracted from the inverter operating mode library, specifically the bias tuning parameters that match the grid connection strength level. The reference threshold is also extracted from the inverter operating mode library, again matching the bias tuning parameters. The grid connection strength level used in the bias weight calculation is the grid connection strength level of the connection point obtained after interpreting the grid connection strength attribute. The natural constants used in the bias weight calculation are fixed mathematical constants that directly participate in the calculation process.

[0043] This calculation process is used to generate the bias weights of the candidate modes. By combining the difference between the grid connection intensity level and the reference threshold with the attenuation coefficient, and through exponential and reciprocal operations, weight information that can characterize the degree to which the candidate mode adapts to the current grid connection intensity level is obtained. This weight information is the bias weight of the candidate mode, which is used to adjust the activation ratio of the grid-connected operation mode and the grid-following operation mode in the future.

[0044] When the grid connection intensity level is higher than the reference threshold, the calculated bias weight gradually decreases as the grid connection intensity level increases. When the grid connection intensity level is lower than the reference threshold, the calculated bias weight gradually increases as the grid connection intensity level decreases. When the grid connection intensity level is equal to the reference threshold, the calculated bias weight will be at a fixed intermediate value. The overall calculation result shows a monotonic trend of change with the grid connection intensity level.

[0045] The matching and tuning unit first clarifies the adaptation priority of each operating mode reflected by the tendency weight. The operating mode with a larger tendency weight indicates that it is more compatible with the current grid connection intensity level and is set with a higher activation ratio. The operating mode with a smaller tendency weight is set with a lower activation ratio. Then, combined with the total number of inverters in the photovoltaic cluster, the number and activation ratio of grid-connected operating mode and grid-following operating mode are calculated when the photovoltaic cluster is actually put into operation. Through this direct corresponding ratio setting method, the activation ratio of the two types of inverters is accurately tuned. The clear ratio relationship after tuning is the activation ratio of grid-connected inverters and grid-following inverters.

[0046] The encapsulation unit organizes and integrates information such as the commissioning ratio, mode selection preference, overall cluster operation orientation, and core requirements for grid connection intensity level of the grid-connected inverters and grid-connected inverters according to the unified data format for overall photovoltaic cluster operation control. It standardizes the data arrangement order and expression form, removes scattered proportional data and irrelevant information, and integrates all relevant content into a complete data set that can characterize the overall cluster mode selection trend and can be directly used for cluster control. This organized and integrated data set is the cluster operation mode tendency of the photovoltaic cluster.

[0047] The mode assignment unit determines the activation ratio of the grid-connected operation mode and the grid-following operation mode based on the cluster operation mode preference. First, it calculates the number of inverters that need to be activated for each of the two operation modes. Then, it sequentially assigns the mode to all inverters in the photovoltaic cluster that are not in operation and are in standby mode. The allocation process is strictly carried out according to the calculated number to ensure that the number of inverters for the two modes meets the activation ratio requirements. After the allocation is completed, each inverter is marked with a unique mark that can clearly distinguish its operation mode type. This unique mark can be directly recognized by the inverter controller and is the mode identifier of the inverter.

[0048] The association mapping unit first extracts the mode identifier of each inverter in the photovoltaic cluster, and then simultaneously extracts the inherent rated capacity of each inverter. This rated capacity is a core parameter fixed at the factory and will not change with the operating status. Then, through the unique device identifier of the inverter, the mode identifier of each inverter is fixedly bound to the corresponding rated capacity one-to-one, ensuring that the operating mode attribute of each inverter and its own rated capacity form an inseparable correspondence. After the binding is completed, each set of corresponding data is packaged into an independent data unit, which is the inverter's mode capacity association tuple.

[0049] The capacity accumulation unit iterates through all mode capacity association tuples within the photovoltaic cluster, proceeding sequentially according to the inverter's device number, ensuring no inverter association tuple is missed. Simultaneously, it checks the mode identifier of each association tuple, filtering out all association tuples with the mode identifier indicating grid-connected operation mode. Then, it extracts the corresponding inverter rated capacity from each filtered association tuple, and continuously accumulates all extracted rated capacities in a fixed order, ensuring no deviation or omission during the accumulation process. The total capacity value obtained after accumulation is the total capacity of the grid-connected units in the photovoltaic cluster.

[0050] The capacity encapsulation unit iterates through all mode capacity-related tuples within the photovoltaic cluster, maintaining consistency with the calculation of the total capacity of grid-connected units. It proceeds sequentially according to the inverter's device number, checking the mode identifier of each related tuple one by one. All related tuples with the mode identifier set to grid-connected operation mode are selected. The corresponding inverter rated capacity is extracted from each selected related tuple. All extracted rated capacities are then continuously accumulated and summarized in a fixed order to ensure the accumulation process is error-free and complete. The total capacity value obtained after accumulation and summarization is the total capacity of the grid-connected units in the photovoltaic cluster.

[0051] The capacity allocation unit first directly compares the total capacity of the grid-connected units with the total capacity of the grid-connected units to calculate the respective proportions of the two types of units in the overall rated capacity of the photovoltaic cluster. Then, based on these proportions, it clarifies the capacity allocation range and operating limits for the grid-connected and grid-connected units, completing the allocation and setting of the overall capacity of the photovoltaic cluster and forming a complete capacity allocation scheme that can directly guide the operation of the units. At the same time, the instruction encapsulation unit encapsulates the mode identifier of each inverter according to a standard format that can be recognized by the inverter control unit, standardizes the transmission structure and expression of the identifier, and converts it into a mode switching instruction that can be directly sent to the inverter and executed by the inverter.

[0052] Step 4: Adjust the active and reactive power output settings of the inverters in the photovoltaic cluster according to the mode switching command and the capacity allocation scheme; In this embodiment of the invention, adjusting the active and reactive power output settings of the inverters in the photovoltaic cluster according to the mode switching command and the capacity allocation scheme includes: The mode switching command is parsed to obtain the inverter's operating mode assignment identifier; The capacity allocation scheme is decomposed into capacity quotas to obtain the active capacity quota and reactive capacity quota of the inverter. Based on the operating mode assignment identifier, the active power output setpoint of the inverter is adaptively tuned to obtain the mode-based active power setpoint of the inverter. Based on the active capacity quota and the reactive capacity quota, capacity constraint allocation is performed on the patterned active capacity setting value and the reactive output setting value of the inverter to obtain the capacity constraint active capacity setting value and the capacity constraint reactive capacity setting value of the inverter. The capacity-constrained active power setting value and the capacity-constrained reactive power setting value are associated as the active and reactive power output setting values ​​of the inverter in the photovoltaic cluster.

[0053] The process of adjusting the modemed active power setpoint and the inverter's reactive power output setpoint based on the active power capacity quota and the reactive power capacity quota to obtain the inverter's capacity-constrained active power setpoint and capacity-constrained reactive power setpoint includes: The active capacity quota and the reactive capacity quota are deconstructed to extract the active capacity quota component and the reactive capacity quota component of the inverter. Based on the active power quota component, the active power upper limit is checked on the patterned active power setting value to obtain the capacity constraint active power setting value of the inverter. Based on the reactive power quota component, the reactive power output setting value of the inverter is clamped by a reactive power threshold to obtain the capacity constraint reactive power setting value of the inverter. The capacity constraint active power setting value and the capacity constraint reactive power setting value are associated and encapsulated to obtain the capacity constraint setting value pair of the inverter.

[0054] The instruction semantic parsing module breaks down and identifies the complete data content of the mode switching instruction segment by segment through the hardware parsing channel. It accurately identifies the operating mode type pointing information and target inverter matching information contained in the instruction. The identified operating mode type pointing information is standardized and organized to form a unique identifier that can uniquely mark the corresponding operating mode of the inverter. This standardized and organized unique identifier is the operating mode assignment identifier of the inverter.

[0055] The capacity quota breakdown module, based on the established overall capacity allocation rules of the photovoltaic cluster in the capacity allocation scheme, and combined with the operating mode assignment identifier of each inverter and the basic capacity information of the equipment itself, breaks down the corresponding cluster-level capacity quota in the capacity allocation scheme and assigns it to each individual inverter. It then determines a dedicated active power allocation limit and reactive power allocation limit for each inverter. The determined active power allocation limit is the active capacity quota of the inverter, and the determined reactive power allocation limit is the reactive capacity quota of the inverter.

[0056] The mode adaptive tuning module adjusts the original active power output setpoint of the inverter according to the inherent control characteristics of the inverter's operating mode corresponding to the operating mode assignment identifier, combined with the control logic and adjustment requirements of the active power output in that operating mode. This ensures that the active power output setpoint fully matches the output characteristics and control objectives of the currently assigned operating mode. The adjusted active power output setpoint is the mode-specific active power setpoint of the inverter.

[0057] The quota decomposition module breaks down the overall capacity constraint information of the active power capacity quota layer by layer, extracting independent active power capacity constraint segments that are adapted to the current control cycle and operating scenario. These extracted independent active power capacity constraint segments are the active power quota components of the inverter. At the same time, the module breaks down the overall capacity constraint information of the reactive power capacity quota layer by layer, extracting independent reactive power capacity constraint segments that are adapted to the current control cycle and operating scenario. These extracted independent reactive power capacity constraint segments are the reactive power quota components of the inverter.

[0058] The active power limit verification module directly compares the patterned active power setpoint with the active power quota component. When the patterned active power setpoint is greater than the active power quota component, the patterned active power setpoint is directly adjusted to the corresponding value of the active power quota component. When the patterned active power setpoint is less than or equal to the active power quota component, the original value of the patterned active power setpoint is directly retained. The final determined active power output value is the capacity constraint active power setpoint of the inverter.

[0059] The reactive power threshold clamping module first reads the upper and lower limits of reactive power output defined by the reactive power quota component. Then, it compares the inverter's reactive power output setting value with these upper and lower limits sequentially. When the reactive power output setting value is greater than the upper limit of the reactive power quota component, it directly adjusts the reactive power output setting value to the upper limit value. When the reactive power output setting value is less than the lower limit of the reactive power quota component, it directly adjusts the reactive power output setting value to the lower limit value. When the reactive power output setting value is between the upper and lower limits, it directly retains the original value of the reactive power output setting value. The final determined reactive power output value is the inverter's capacity constraint reactive power setting value.

[0060] The setpoint association encapsulation module binds and combines the capacity constraint active power setpoint and the capacity constraint reactive power setpoint according to the data arrangement order required for real-time control of the inverter. It standardizes the transmission structure and correspondence of the two sets of setpoints, forming a control reference data combination that matches each other and transmits synchronously. The control reference data combination after standard binding is the capacity constraint setpoint pair of the inverter.

[0061] The data association module directly binds and associates the capacity constraint active power setpoint with the capacity constraint reactive power setpoint, so that the two sets of setpoints verified by the capacity constraint form a unified output control basis. This unified output control basis directly serves as the active and reactive power output execution standard for each inverter in the photovoltaic cluster. This execution standard is the active and reactive power output setpoint of the inverter in the photovoltaic cluster.

[0062] Step 5: Based on the adjusted active and reactive power output settings, coordinate the output between inverters in the photovoltaic cluster and respond to the frequency and voltage changes of the target distribution network to obtain the coordinated control command of the target distribution network. In this embodiment of the invention, the step of coordinating the outputs of inverters in the photovoltaic cluster based on the adjusted active and reactive power output setpoints, and responding to frequency and voltage changes in the target distribution network to obtain the coordinated control command for the target distribution network, includes: Based on the adjusted active and reactive power output settings, the real-time output margin of the inverters in the photovoltaic cluster is aggregated and mapped to obtain the cluster output capacity status of the photovoltaic cluster. The grid connection frequency of the target distribution network is perturbed and decoupled to extract the frequency offset of the target distribution network and obtain the frequency deviation characteristic quantity of the target distribution network. The grid-connected voltage of the target distribution network is analyzed for fluctuations to extract the voltage amplitude offset of the target distribution network and obtain the voltage fluctuation characteristic quantity of the target distribution network. Based on the frequency deviation characteristic and the voltage fluctuation characteristic, the power output capability status of the cluster is modulated to obtain the response modulation command of the inverter. The response modulation commands are fused and prioritized to obtain the coordinated control commands for the target distribution network.

[0063] The adjusted active and reactive power output setpoints are directly used as the benchmark for inverter output adjustment. The real-time active and reactive power output values ​​of each inverter in the photovoltaic cluster are collected one by one. The real-time output value of each inverter is compared with the corresponding adjusted active and reactive power output setpoints to determine the output margin value that can be adjusted upward or downward for a single inverter. Then, the output margin values ​​of all inverters are uniformly collected and integrated, and fully mapped according to the dimension of the overall output adjustment of the photovoltaic cluster to form an overall status information that can fully reflect the overall adjustable output range and power support capability of the entire photovoltaic cluster. This overall status information is the cluster output capability status of the photovoltaic cluster.

[0064] Real-time grid-connected frequency data at the grid-connected nodes of the target distribution network are continuously collected. Random disturbance components, external interference components, and inherent frequency change components in the collected continuous grid-connected frequency data are separated. All irrelevant disturbance and interference data are eliminated, and only the core offset data of the grid-connected frequency deviating from the rated operating frequency is retained. These core offset data are standardized and organized to form characteristic information that can accurately characterize the degree and trend of frequency deviation. This characteristic information is the frequency deviation characteristic quantity of the target distribution network.

[0065] Real-time acquisition of grid-connected voltage amplitude data at the grid-connected nodes of the target distribution network; point-by-point fluctuation state analysis of the continuously acquired voltage amplitude data; differentiation between steady-state operating values ​​and dynamic fluctuation values ​​of voltage amplitude; removal of interference components belonging to normal fluctuations in voltage amplitude; accurate extraction of core offset data of voltage amplitude deviating from rated voltage amplitude; systematic integration of these core offset data to form characteristic information that can completely characterize voltage fluctuation amplitude and fluctuation state, which is the voltage fluctuation characteristic quantity of the target distribution network.

[0066] First, the frequency deviation characteristic quantity reflects the degree of frequency deviation and the corresponding frequency adjustment requirement. Then, the voltage fluctuation characteristic quantity reflects the voltage fluctuation amplitude and the corresponding voltage adjustment requirement. Combined with the overall adjustable output range and power support capability of the photovoltaic cluster as shown by the cluster output capability status, and in accordance with the principle of matching frequency adjustment with voltage adjustment, the output capability status of the cluster is adjusted and adapted in a targeted manner. The adjusted output adjustment requirements are then converted into control command information that can be directly applied to the inverter. This control command information is the inverter's response modulation command.

[0067] The response modulation commands corresponding to all inverters in the photovoltaic cluster are collected, commands with the same control objectives and adjustment directions are merged and integrated, and conflicting content and redundant information in the commands are removed. Then, the execution priority of each command is determined according to the order of frequency stability adjustment, voltage stability adjustment, and power balance adjustment. All commands after merging and priority arrangement are integrated into a unified command set that adapts to the global operation control of the entire target distribution network, which is the collaborative control command of the target distribution network.

[0068] Step 6: Integrate the preliminary control command, the output setpoint, and the collaborative control command to obtain the comprehensive control command set of the target distribution network, and send it to the inverters in the photovoltaic cluster.

[0069] In this embodiment of the invention, the step of integrating the preliminary control command, the output setpoint, and the coordinated control command to obtain a comprehensive control command set for the target distribution network, and then issuing it to the inverters in the photovoltaic cluster, includes: The initial control command, the output set value, and the coordinated control command are semantically aligned to obtain the alignment command set of the target distribution network; The execution conflicts of the instructions in the alignment instruction set are arbitrated in a timing manner to obtain the timing arrangement instruction table of the target distribution network; The timing arrangement instruction table is aggregated and encapsulated to obtain the comprehensive control instruction set of the target distribution network; Based on the comprehensive control instruction set, instructions are broadcast and pushed to the control ports of the inverters in the photovoltaic cluster.

[0070] The preliminary control command, output setpoint, and coordinated control command each contain independent control semantic information. After the command semantic alignment unit is activated, it first parses the semantics of the preliminary control command to clarify its control objective, adjustment direction, and target. Then, it parses the semantics of the output setpoint to clarify its output reference, constraint range, and target. Simultaneously, it parses the semantics of the coordinated control command to clarify its global adjustment objective, priority requirements, and scope. Subsequently, it compares the three sets of parsed semantic information one by one to unify the expression of the control objective, the judgment criteria for the adjustment direction, and the referential range of the target, eliminating semantic ambiguity and expression differences among the three sets of commands. All commands after semantic unification are integrated and collected to form a semantically clear, consistent, and unambiguous command set. This command set is the alignment command set of the target distribution network.

[0071] In the alignment instruction set, the same inverter may receive multiple instructions with different adjustment requirements at the same time node. After the timing arbitration unit is started, it first traverses all instructions in the alignment instruction set, identifies instruction combinations with execution conflicts one by one, clarifies the control objective, adjustment direction and execution time of each group of conflicting instructions, and then determines the execution priority of each group of conflicting instructions according to the established rules of global coordinated control taking precedence over local control and time urgency taking precedence over time leniency. Subsequently, all instructions are time-series arranged in order of priority from high to low, and each instruction is assigned a unique execution time node and execution sequence number. The arranged instructions are organized into an ordered instruction table according to the execution order. This ordered instruction table is the timing arrangement instruction table of the target distribution network.

[0072] The instructions in the timing orchestration instruction table are arranged in a distributed manner according to the execution order. After the instruction set aggregation and encapsulation unit is started, it first groups and collects the instructions in the timing orchestration instruction table according to the unique identifier of the inverter, and integrates all instructions corresponding to the same inverter into the same group. Then, the instructions in each group are sorted again according to the execution time order to remove duplicate instruction content and redundant control information. Subsequently, the instructions in each group are encapsulated according to the standard format that the inverter control port can recognize, forming a subset of control instructions adapted to a single inverter. Finally, the subsets of control instructions of all inverters are integrated to form a unified instruction set covering the entire photovoltaic cluster. This unified instruction set is the comprehensive control instruction set of the target distribution network.

[0073] The integrated control instruction set contains control instructions for all inverters within the photovoltaic cluster. After the instruction broadcasting and pushing unit is activated, it first reads the control port address and communication parameters corresponding to each inverter, establishes a stable communication connection with the control port of each inverter, and then pushes the corresponding subset of control instructions to its control port in sequence according to the timing arrangement requirements of the integrated control instruction set. During the pushing process, the transmission status of the instructions is monitored in real time to confirm that each instruction has been successfully received by the inverter control port. If a transmission interruption or instruction loss occurs, the corresponding instruction is immediately re-pushed until all instructions have been effectively pushed, ensuring that the inverter can execute the corresponding control operation according to the integrated control instruction set.

[0074] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0075] This application embodiment can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence is the theory, method, technology, and application system that uses digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to obtain optimal results.

[0076] This disclosure provides a grid-connected photovoltaic (PV) cluster capacity configuration device 300 based on short-circuit ratio sensing, including a processor 304 and a memory 301. Optionally, the device may further include a communication interface 302 and a bus 303. The processor 304, communication interface 302, and memory 301 can communicate with each other via the bus 303. The communication interface 302 can be used for information transmission. The processor 304 can call logical instructions in the memory 301 to execute the grid-connected PV cluster capacity configuration method based on short-circuit ratio sensing described in the above embodiment.

[0077] Furthermore, the logic instructions in the aforementioned memory 301 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0078] The memory 301, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 304 executes functional applications and data processing by running the program instructions / modules stored in the memory 301, thereby realizing the grid-connected photovoltaic cluster unit capacity configuration method based on short-circuit ratio sensing in the above embodiments.

[0079] The memory 301 may include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 301 may include high-speed random access memory and may also include non-volatile memory. The technical solutions of this disclosure embodiment can be embodied in the form of a software product stored in a storage medium, including one or more instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in this disclosure embodiment. The aforementioned storage medium may be a non-transitory storage medium, including: USB flash drive, mobile hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk, etc., and other media capable of storing program code; it may also be a transient storage medium.

[0080] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0081] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0082] The methods and products (including but not limited to devices and equipment) disclosed in the embodiments herein can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed between each other may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected to implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0083] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing, characterized in that, The method includes: Step 1: Integrate the short-circuit ratio of the grid connection point in the target distribution network, the output power and voltage of the photovoltaic cluster, and the interference measurement values ​​characterizing the fluctuations in light and voltage into the real-time operating data of the target distribution network; Step 2: Based on the measured interference value and the preset inverter reference parameters, adaptively adjust the actual output response and expected response of the inverter in the photovoltaic cluster to obtain the initial control command of the inverter; Step 3: Based on the short-circuit ratio, determine the operating mode ratio of the grid-connected inverters and the grid-following inverters in the photovoltaic cluster, and obtain the mode switching command and capacity allocation scheme of the photovoltaic cluster. Step 4: Adjust the active and reactive power output settings of the inverters in the photovoltaic cluster according to the mode switching command and the capacity allocation scheme; Step 5: Based on the adjusted active and reactive power output settings, coordinate the output between inverters in the photovoltaic cluster and respond to the frequency and voltage changes of the target distribution network to obtain the coordinated control command of the target distribution network; Step 6: Integrate the preliminary control command, the output setpoint, and the collaborative control command to obtain the comprehensive control command set of the target distribution network, and send it to the inverters in the photovoltaic cluster.

2. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 1, characterized in that, The process of integrating the short-circuit ratio at the grid connection point in the target distribution network, the output power and voltage of the photovoltaic cluster, and interference measurements characterizing irradiance and voltage fluctuations into real-time operating data of the target distribution network includes: By using the synchronous phasor measurement unit at the grid connection point in the target distribution network, the voltage phasor and current phasor of the grid connection point are collected to generate the short-circuit capacity of the grid connection point. Extract the short-circuit ratio of the grid connection point from the short-circuit capacity; The local controller of the inverter in the photovoltaic cluster in the target distribution network reads the real-time output active power, real-time output reactive power and grid-connected voltage amplitude of the inverter, and aggregates them into the output power and voltage of the photovoltaic cluster. The system obtains the sampled values ​​of solar irradiance in the area where the photovoltaic cluster is located under a continuous time series, and obtains the sampled values ​​of instantaneous voltage under a synchronous time series from the voltage monitoring device at the grid connection point. The sampled values ​​of light irradiance and the sampled values ​​of instantaneous voltage are correlated to form an interference measurement value characterizing the fluctuations in light and voltage; Using a unified timestamp identifier, the short-circuit ratio, the output power and voltage, and the interference measurement values ​​are recombined to obtain the real-time operating data of the target distribution network.

3. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 1, characterized in that, The step of adaptively adjusting the actual output response and expected response of the inverter in the photovoltaic cluster based on the interference measurement value and the preset inverter reference parameters to obtain the initial control command of the inverter includes: Read the actual active and reactive power output of the inverter in the photovoltaic cluster during the current control cycle to obtain the actual output response of the inverter. The sampled values ​​of light irradiance and instantaneous voltage in the interference measurement are mapped and matched with the preset inverter reference parameters to obtain the expected active power reference value and the expected reactive power reference value of the inverter. The expected active power reference value and the expected reactive power reference value are correlated to form the expected response of the inverter; The actual output response is compared with the expected response point by point to generate the active power deviation indication and reactive power deviation indication of the inverter. Based on the active power deviation indication and the reactive power deviation indication, adjust the active axis reference value and the reactive axis reference value of the inverter's inner current loop so that the actual output response approaches the expected response. The adjusted active axis reference value and reactive axis reference value of the inner current loop are formatted and encapsulated to obtain the initial control command of the inverter.

4. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 1, characterized in that, Based on the short-circuit ratio, the operating modes of grid-connected inverters and grid-linked inverters in the photovoltaic cluster are matched to obtain the mode switching command and capacity allocation scheme of the photovoltaic cluster, including: The grid connection strength attribute of the grid connection access point is obtained by interpreting the short-circuit ratio. Based on the grid connection strength attribute, mode tendency is extracted from the preset inverter operation mode library to obtain the cluster operation mode tendency of the photovoltaic cluster. The cluster operation mode tendency includes the activation ratio of grid-connected inverters and grid-following inverters. Based on the cluster's operating mode preference, the inverters in the photovoltaic cluster that are in standby mode are assigned operating modes to obtain the mode identifiers of the inverters. Based on the mode identifier, the rated capacity of inverters assigned with grid-connected operation mode identifiers is aggregated for grid-connected capacity, and the rated capacity of inverters assigned with grid-following operation mode identifiers is aggregated for grid-following capacity, so as to obtain the total capacity of grid-connected units and the total capacity of grid-following units in the photovoltaic cluster. Based on the total capacity of the grid-connected units and the total capacity of the grid-following units, the capacity allocation ratio of the photovoltaic cluster is proportionally adjusted to obtain the capacity allocation scheme of the photovoltaic cluster, and the mode identifier of the inverter is encapsulated into the corresponding mode switching instruction.

5. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 4, characterized in that, Based on the grid connection strength attribute, a mode preference extraction is performed on a preset inverter operation mode library to obtain the cluster operation mode preference of the photovoltaic cluster. The cluster operation mode preference includes the activation ratio of grid-connected inverters and grid-following inverters, including: The grid connection strength attribute is interpreted to obtain the grid connection strength level of the grid connection access point; Based on the grid connection strength level, the attenuation coefficient and reference threshold are extracted from the preset inverter operation mode library to obtain the mode tendency tuning parameters of the photovoltaic cluster. Based on the grid connection strength level, the inverter operation mode library is filtered by mode domain to obtain the candidate modes of the photovoltaic cluster; Based on the grid connection strength level and the mode preference tuning parameters, the operating mode preference assessment is performed on the candidate modes to obtain the preference weight of the candidate modes. The formula for calculating the preference weight is as follows: ； In the formula, This represents the bias weight. Represents the natural constant. This represents the attenuation coefficient. This indicates the grid connection strength level. This represents the reference threshold; Based on the aforementioned bias weights, the activation ratio of the grid-connected operation mode and the grid-following operation mode in the candidate modes is adjusted to obtain the activation ratio of the grid-connected inverter and the grid-following inverter. The activation ratio is encapsulated with a mode preference to obtain the cluster operation mode preference of the photovoltaic cluster.

6. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 4, characterized in that, Based on the mode identifier, the rated capacity of inverters assigned with grid-connected operation mode identifiers is aggregated for grid-connected capacity, and the rated capacity of inverters assigned with grid-following operation mode identifiers is aggregated for grid-following capacity, to obtain the total capacity of grid-connected units and the total capacity of grid-following units in the photovoltaic cluster, including: The mode identifier and corresponding rated capacity of the inverter in the photovoltaic cluster are associated and mapped to obtain the mode capacity association tuple of the inverter; Based on the aforementioned mode capacity association tuple, the rated capacity of inverters with mode identifiers of grid-connected operation mode is aggregated to obtain the total capacity of the grid-connected units of the photovoltaic cluster. Based on the aforementioned mode capacity association tuple, the rated capacity of inverters with the mode identifier set to grid-connected operation mode is encapsulated for capacity matching to obtain the total capacity of the grid-connected units in the photovoltaic cluster.

7. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 1, characterized in that, The step of adjusting the active and reactive power output settings of the inverters in the photovoltaic cluster according to the mode switching command and the capacity allocation scheme includes: The mode switching command is parsed to obtain the inverter's operating mode assignment identifier; The capacity allocation scheme is decomposed into capacity quotas to obtain the active capacity quota and reactive capacity quota of the inverter. Based on the operating mode assignment identifier, the active power output setpoint of the inverter is adaptively tuned to obtain the mode-based active power setpoint of the inverter. Based on the active capacity quota and the reactive capacity quota, capacity constraint allocation is performed on the patterned active capacity setting value and the reactive output setting value of the inverter to obtain the capacity constraint active capacity setting value and the capacity constraint reactive capacity setting value of the inverter. The capacity-constrained active power setting value and the capacity-constrained reactive power setting value are associated as the active and reactive power output setting values ​​of the inverter in the photovoltaic cluster.

8. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 7, characterized in that, The process of adjusting the modemed active power setpoint and the inverter's reactive power output setpoint based on the active power capacity quota and the reactive power capacity quota to obtain the inverter's capacity-constrained active power setpoint and capacity-constrained reactive power setpoint includes: The active capacity quota and the reactive capacity quota are deconstructed to extract the active capacity quota component and the reactive capacity quota component of the inverter. Based on the active power quota component, the active power upper limit is checked on the patterned active power setting value to obtain the capacity constraint active power setting value of the inverter. Based on the reactive power quota component, the reactive power output setting value of the inverter is clamped by a reactive power threshold to obtain the capacity constraint reactive power setting value of the inverter. The capacity constraint active power setting value and the capacity constraint reactive power setting value are associated and encapsulated to obtain the capacity constraint setting value pair of the inverter.

9. The method for configuring the capacity of grid-connected photovoltaic cluster units based on short-circuit ratio sensing as described in claim 1, characterized in that, Based on the adjusted active and reactive power output setpoints, the system coordinates the output between inverters in the photovoltaic cluster and responds to frequency and voltage changes in the target distribution network to obtain coordinated control commands for the target distribution network, including: Based on the adjusted active and reactive power output settings, the real-time output margin of the inverters in the photovoltaic cluster is aggregated and mapped to obtain the cluster output capacity status of the photovoltaic cluster. The grid connection frequency of the target distribution network is perturbed and decoupled to extract the frequency offset of the target distribution network and obtain the frequency deviation characteristic quantity of the target distribution network. The grid-connected voltage of the target distribution network is analyzed for fluctuations to extract the voltage amplitude offset of the target distribution network and obtain the voltage fluctuation characteristic quantity of the target distribution network. Based on the frequency deviation characteristic and the voltage fluctuation characteristic, the power output capability status of the cluster is modulated to obtain the response modulation command of the inverter. The response modulation commands are fused and prioritized to obtain the coordinated control commands for the target distribution network; The process of integrating the initial control command, the output setpoint, and the coordinated control command to obtain a comprehensive control command set for the target distribution network, and then distributing it to the inverters in the photovoltaic cluster, includes: The initial control command, the output set value, and the coordinated control command are semantically aligned to obtain the alignment command set of the target distribution network; The execution conflicts of the instructions in the alignment instruction set are arbitrated in a timing manner to obtain the timing arrangement instruction table of the target distribution network; The timing arrangement instruction table is aggregated and encapsulated to obtain the comprehensive control instruction set of the target distribution network; Based on the comprehensive control instruction set, instructions are broadcast and pushed to the control ports of the inverters in the photovoltaic cluster.

10. A capacity configuration device for grid-connected photovoltaic cluster units based on short-circuit ratio sensing, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute, when running the program instructions, the grid-connected photovoltaic cluster unit capacity configuration method based on short-circuit ratio sensing as described in any one of claims 1-9.

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