A method and system for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid

Abstract

The present invention discloses a method and system for evaluating the possibility of large-scale inverter interface distributed power sources being disconnected from the grid: obtaining structural parameters and data parameters of a target power system after connecting to the inverter interface distributed power source, and establishing a topological node model containing the data parameters; calculating the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing the data parameters, and performing the first inverter interface distributed power source partitioning according to a preset first offline judgment logic; performing equivalent calculation on the inverter interface distributed power source after the partitioning, and performing offline operation; obtaining the grid connection point voltages of the remaining different inverter interface distributed power sources after the offline operation, and performing the second inverter interface distributed power source partitioning according to the preset first offline judgment logic, and performing offline operation. The method can not only effectively evaluate and process the possibility of the inverter interface distributed power source being disconnected from the grid, but also improve the stability and reliability of the power system.

Description

Technical Field

[0001] The present invention relates to the technical field of off-grid possibility evaluation of large-scale inverter-type interface distributed power sources, and in particular to a method and system for evaluating off-grid possibility of large-scale inverter-type interface distributed power sources. Background Art

[0002] With the widespread application of renewable energy and the continuous development of power systems, inverter-interface distributed power sources play an increasingly important role in power systems. However, the access of inverter-interface distributed power sources will have a certain impact on the stable operation of the power system, especially in the case of large-scale access. Therefore, evaluating the possibility of disconnection of large-scale inverter-interface distributed power sources is of great significance to ensure the stable operation of the power system.

[0003] Traditional off-grid possibility evaluation methods are often based on simple threshold judgments or empirical formulas, which fail to fully consider the complexity and diversity of the power system after the inverter-type interface distributed power generation is connected. Therefore, the existing evaluation methods have certain limitations in accuracy and reliability, and it is difficult to meet the needs of practical applications. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a method and system for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid, which can solve the problems mentioned in the background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid, comprising:

[0009] Acquire structural parameters and data parameters of the target power system after connecting to the inverter interface distributed power source, and establish a topological node model including the data parameters according to the structural parameters and data parameters;

[0010] Calculating the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing the data parameters, and performing the first inverter interface distributed power source partitioning according to the preset first off-grid judgment logic;

[0011] Perform equivalent calculation on the partitioned inverter interface distributed power sources, and disconnect the inverter interface distributed power sources that meet the disconnection requirements in the first disconnection judgment logic according to the calculation results combined with the first disconnection judgment logic;

[0012] The grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation are obtained, and the second inverter interface distributed power source partition is performed according to the preset first off-grid judgment logic, and the off-grid operation is performed.

[0013] As a preferred solution of the method for evaluating the possibility of large-scale inverter-type interface distributed power supply being disconnected from the grid according to the present invention, it also includes:

[0014] Performing a second inverter interface distributed power generation partition according to a preset first off-grid judgment logic;

[0015] Perform equivalent calculation on the inverter-type interface distributed power source after the second partition, and disconnect the inverter-type interface distributed power source that meets the disconnection requirement in the first disconnection judgment logic according to the calculation result and the first disconnection judgment logic;

[0016] Obtaining the grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation, performing a third inverter interface distributed power partition according to the preset first off-grid judgment logic, and performing the off-grid operation;

[0017] Repeat the off-grid and partitioning operations until all the inverter-type interface distributed power sources on the non-fault lines are not off-grid and all the inverter-type interface distributed power sources on the faulty lines are off-grid, obtain the number of inverter-type interface distributed power sources that are off-grid, and perform a possibility evaluation.

[0018] As a preferred solution of the method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid according to the present invention, the method of calculating the grid connection point voltages of different inverter-type interface distributed power sources according to the topological node model containing data parameters includes:

[0019] Obtain the upstream and downstream fault current values ​​of the grid connection point voltage before a certain inverter-type interface distributed power source is connected;

[0020] Obtaining the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system;

[0021] The grid connection point voltage value after the inverter interface distributed power source is connected to the power system is calculated according to the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system.

[0022] As a preferred solution of the method for evaluating the possibility of large-scale inverter-type interface distributed power supply being disconnected from the grid according to the present invention, the first partitioning of the inverter-type interface distributed power supply according to the preset first disconnection judgment logic includes:

[0023] Prioritizing partitioning of the topological node model, and recording the partitioned topological node model as a fault partition and a non-fault partition;

[0024] When the grid connection point voltage value of a certain inverter interface distributed power source is less than the first grid connection threshold after it is connected to the power system, it is recorded as the inverter interface distributed power source is within the first partition range;

[0025] When the grid connection point voltage value of a certain inverter interface distributed power source is not less than the first grid connection threshold value and not greater than the second threshold value after the inverter interface distributed power source is connected to the power system, and the inverter interface distributed power source is located in the fault zone, the inverter interface distributed power source is recorded as being within the second zone range;

[0026] When a certain inverter-type interface distributed power source is connected to the power system, the grid connection point voltage value is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter-type interface distributed power source is located in a non-fault partition, it is recorded that the inverter-type interface distributed power source is within the third partition range;

[0027] When the voltage value of the grid connection point of a certain inverter-type interface distributed power source is not less than the second grid connection threshold after it is connected to the power system, it is recorded that the inverter-type interface distributed power source is within the fourth zone.

[0028] As a preferred scheme of the method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid described in the present invention, the equivalent calculation of the partitioned inverter-type interface distributed power sources includes: performing equivalent calculations on the inverter-type interface distributed power sources within the first partition range, the second partition range, the third partition range, and the fourth partition range according to a preset equivalent logic.

[0029] As a preferred solution of the method for evaluating the possibility of large-scale inverter-type interface distributed power supply being disconnected from the grid according to the present invention, the second inverter-type interface distributed power supply partitioning is performed according to the preset first disconnection judgment logic; including:

[0030] Obtain the upstream and downstream fault current values ​​of the grid connection point voltage before the remaining distributed power sources with different inverter interfaces are connected after the off-grid operation;

[0031] Obtaining the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system;

[0032] The grid connection point voltage value after the inverter interface distributed power source is connected to the power system after the off-grid operation is calculated based on the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system.

[0033] As a preferred solution of the method for evaluating the possibility of off-grid disconnection of a large-scale inverter-type interface distributed power source according to the present invention, the equivalent calculation of the inverter-type interface distributed power source after the second partitioning, and the off-grid disconnection of the inverter-type interface distributed power source that meets the off-grid disconnection requirement in the first off-grid disconnection judgment logic according to the calculation result in combination with the first off-grid judgment logic includes:

[0034] When the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is less than the first grid connection threshold, the inverter interface distributed power source is recorded as being within the first partition range;

[0035] When the grid-connected voltage value of a certain inverter-type interface distributed power source after being connected to the power system after the off-grid operation is not less than the first grid-connected threshold value and not greater than the second threshold value, and the inverter-type interface distributed power source is located in the fault partition, the inverter-type interface distributed power source is recorded as being within the second partition range;

[0036] When the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter interface distributed power source is located in a non-fault partition, it is recorded that the inverter interface distributed power source is within the third partition range;

[0037] When the voltage value of the grid connection point after a certain inverter-type interface distributed power source is connected to the power system after the off-grid operation is performed is not less than the second grid connection threshold, the inverter-type interface distributed power source is recorded as being within the fourth zone.

[0038] In a second aspect, the present invention provides a large-scale inverter-type interface distributed power supply off-grid possibility evaluation system, comprising:

[0039] A model building module, used to obtain structural parameters and data parameters of the target power system after connecting to the inverter interface distributed power source, and to build a topological node model including the data parameters according to the structural parameters and data parameters;

[0040] A partitioning module, used to calculate the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing data parameters, and perform the first inverter interface distributed power source partitioning according to a preset first off-grid judgment logic;

[0041] The off-grid judgment module is used to perform equivalent calculation on the inverter-type interface distributed power source after partitioning, and to disconnect the inverter-type interface distributed power source that meets the off-grid requirement in the first off-grid judgment logic according to the calculation result combined with the first off-grid judgment logic;

[0042] The off-grid operation module is used to obtain the grid connection point voltages of the remaining different inverter-type interface distributed power sources after the off-grid operation, and to perform a second inverter-type interface distributed power source partition according to the preset first off-grid judgment logic, and to perform the off-grid operation.

[0043] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method when executing the computer program.

[0044] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the method described above when executed by a processor.

[0045] Compared with the prior art, the present invention has the following beneficial effects: the present invention proposes a method and system for evaluating the possibility of large-scale inverter interface distributed power sources being disconnected from the grid, obtains structural parameters and data parameters of a target power system after connecting to the inverter interface distributed power source, and establishes a topological node model containing data parameters according to the structural parameters and data parameters; calculates the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing data parameters, and performs a first inverter interface distributed power source partitioning according to a preset first offline judgment logic; performs equivalent calculation on the partitioned inverter interface distributed power sources, and disconnects the inverter interface distributed power sources that meet the offline requirements in the first offline judgment logic according to the calculation results combined with the first offline judgment logic; obtains the grid connection point voltages of the remaining different inverter interface distributed power sources after the offline operation, and performs a second inverter interface distributed power source partitioning according to the preset first offline judgment logic, and performs an offline operation.

[0046] It can not only effectively evaluate and handle the possibility of the inverter-type interface distributed power source being disconnected from the grid, but also improve the stability and reliability of the power system. Specifically, the present invention can accurately reflect the actual operation of the power system by establishing a topological node model containing data parameters. According to the model, the present invention can calculate the grid connection point voltage of different inverter-type interface distributed power sources, and perform partitioning in combination with the preset offline judgment logic, and then evaluate the possibility of offline. Through multiple partitioning and offline operations, the present invention can gradually optimize the operating state of the power system and reduce the impact of the inverter-type interface distributed power source being disconnected from the grid on the system.

[0047] In summary, the method and system for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid of the present invention are not only innovative in theory, but also have broad prospects and important value in practical applications. Through the implementation of the present invention, the safety and reliability of the power system can be improved, the losses caused by the disconnection of the inverter-type interface distributed power sources from the grid can be reduced, and a strong guarantee can be provided for the stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0049] Figure 1 A method flow chart of a method for evaluating the possibility of off-grid disconnection of a large-scale inverter-type interface distributed power source provided by an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of grid connection point voltage calculation for a method for evaluating the possibility of off-grid operation of a large-scale inverter-type interface distributed power source provided by one embodiment of the present invention;

[0051] Figure 3 A schematic diagram of a topological node model of a method for evaluating the possibility of off-grid disconnection of a large-scale inverter-type interface distributed power source provided by an embodiment of the present invention;

[0052] Figure 4 An internal structural diagram of a computer device for a method for evaluating the possibility of off-grid operation of a large-scale inverter-type interface distributed power source provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0054] Example 1, reference Figure 1-Figure 4 , is the first embodiment of the present invention, which provides a large-scale inverter interface distributed power supply off-grid possibility evaluation method and system, including a large-scale inverter interface distributed power supply off-grid possibility evaluation method and a large-scale inverter interface distributed power supply off-grid possibility evaluation system, wherein a large-scale inverter interface distributed power supply off-grid possibility evaluation method includes:

[0055] Before describing the embodiments of the present application in detail, some related concepts are first explained for the sake of clarity.

[0056] Inverter interface distributed power: Inverter interface distributed power refers to distributed generation units connected to the power grid through power electronic inverters. The power generated by these generators may initially be in the form of DC (such as from solar panels or fuel cells) or need to be converted to DC (such as the AC power generated by wind turbines after rectification), and then converted into AC power that meets grid quality standards through high-performance inverters and connected to the grid. The "inverter interface" here emphasizes the key technical link in the connection between this type of generator and the grid, that is, the role of the inverter is not only to convert the form of electrical energy, but also to ensure that the frequency, phase and voltage of the output current match the grid, while realizing the necessary control functions, such as maximum power point tracking (MPPT), low voltage ride-through (LVRT) and rapid response and protection in the event of grid failure (such as the off-grid function mentioned above).

[0057] Topology Node Model: Topology Node Model is a mathematical model in power system analysis, which is used to represent the structure and component characteristics of the power network. In this model, the power system is simplified into a network diagram consisting of nodes (representing generators, load points, substations, etc.) and branches (representing transmission lines, transformers, etc.). Each node and branch has corresponding electrical parameters, such as the injected power and voltage of the node, and the resistance, reactance and admittance of the branch. Through this model, it is convenient to calculate and study the power system's power flow distribution, stability analysis, fault simulation and other issues. When dealing with the problem of inverter-type distributed power access, the topology node model can help analyze its impact on the system voltage and current distribution.

[0058] Islanding: Islanding, in the power system, refers to the process in which a distributed power source (such as a photovoltaic system connected to an inverter) actively or passively disconnects from the main grid when it detects a power outage or grid anomaly (such as a voltage drop or frequency deviation from the normal range) to protect the safety of the equipment, prevent reverse power supply to the grid, or affect the safety of maintenance personnel. The islanding function is an important safety mechanism of the inverter, ensuring that the distributed power source can operate independently or shut down safely when the grid fails to avoid interfering with the grid recovery process. Islanding can be achieved by detecting grid frequency, voltage changes, or communication signals, and is one of the key technologies in the design of distributed power generation systems.

[0059] In related technologies, the evaluation of the possibility of inverter-type interface distributed power sources going offline usually relies on traditional power system analysis methods and models. However, these methods often ignore the particularity and complexity of inverter-type interface distributed power sources and cannot accurately reflect their offline risks in actual operation.

[0060] The present application provides a method for effectively solving the above-mentioned problems. Next, a plurality of embodiments will be combined to explain in detail how to implement the method for evaluating the possibility of large-scale inverter-type interface distributed power supply being disconnected from the grid.

[0061] Figure 1 A method flow chart of a method for evaluating the possibility of off-grid disconnection of a large-scale inverter-type interface distributed power source is shown, including:

[0062] S101, obtaining structural parameters and data parameters of a target power system after connecting to an inverter interface distributed power source, and establishing a topological node model including the data parameters according to the structural parameters and the data parameters;

[0063] In an optional embodiment, the structural parameters and data parameters can be obtained by collecting detailed structural information of the target power system, including but not limited to the location of the substation, the type and length of the transmission line, the parameters of the transformer (rated capacity, ratio, etc.), the distribution of load points and their load characteristics (such as static load, dynamic load ratio), and the basic data of the existing distributed power sources. For the newly connected inverter-type distributed power sources, collect their technical specifications, such as rated power, maximum output current, voltage range, inverter control strategy (such as maximum power point tracking capability, low voltage ride-through capability), as well as their geographical location and grid connection point information. Through smart meters, sensors and remote monitoring systems, collect real-time data on the current system operating status, including voltage, current, frequency, power factor, etc., as well as the impact of historical fault records and weather conditions on the power generation of distributed power sources.

[0064] In an optional embodiment, the collected data needs to be preprocessed to remove outliers and missing data, correct measurement errors, and ensure data accuracy and consistency. Confirm that the timestamps and geographic coordinates of all data correspond correctly to ensure data synchronization when building the model. Convert data from different sources and scales into a unified standard format to facilitate unified processing and comparison of models.

[0065] In an optional embodiment, each key point in the system (such as a substation, load center, inverter grid connection point) is defined as a node in the model, and its electrical parameters (such as voltage level, active and reactive power demand or supply) are recorded. According to the actual grid structure, the nodes are connected with branches (representing transmission lines and transformer connections), and the impedance, admittance, maximum transmission capacity and other parameters of the branches are recorded. A virtual node is created for each inverter-type distributed power source in the model, and its behavior in the system is defined according to the characteristic model of the inverter (such as PQ curve, control strategy response function). If dynamic simulation is required, dynamic models of generators, loads and lines, as well as a fast control response model of the inverter, are also required.

[0066] In the embodiment of the present application, the simplest straight line connection from the fault to the power system is adopted, and the status of several inverter-type interface distributed power sources are externally connected to the connection line for analysis.

[0067] It should be noted that by constructing a topological node model containing data parameters, the actual operating status and characteristics of the power system can be more accurately reflected. This model not only takes into account the static structure of the power system, but also incorporates the dynamic behavior and control strategy of the inverter-type interface distributed power source, so that the possibility of off-grid can be more comprehensively evaluated. In addition, preprocessing data can ensure the accuracy and consistency of the model, providing a reliable basis for subsequent analysis and calculation. Incorporating the inverter-type distributed power source into the model in the form of a virtual node can easily simulate and analyze its behavior in different scenarios, providing strong support for the evaluation of the possibility of off-grid. At the same time, this modeling method also takes into account the dynamic characteristics of the power system, making the evaluation results closer to the actual operation.

[0068] S102, calculating the grid connection point voltages of different inverter interface distributed power sources according to a topological node model including data parameters, and performing a first inverter interface distributed power source partitioning according to a preset first off-grid judgment logic;

[0069] The calculation of the grid connection point voltage of different inverter-type interface distributed power sources according to the topological node model containing data parameters includes: obtaining the upstream and downstream fault current values ​​of the grid connection point voltage before a certain inverter-type interface distributed power source is connected;

[0070] Furthermore, the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system are obtained;

[0071] Furthermore, the grid connection point voltage value after the inverter interface distributed power source is connected to the power system is calculated based on the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected to the power system and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system.

[0072] In the embodiments of the present application, Figure 2 As shown, the specific operation of obtaining the upstream and downstream fault current values ​​of the grid connection point voltage before a certain inverter interface distributed power source is connected can be:

[0073] ,

[0074] in, Indicates the upstream fault current value of a certain inverter interface distributed power source before it is connected to the grid. Indicates the fault current value downstream of a certain inverter interface distributed power source before it is connected to the grid. Indicates load The magnitude of the voltage source, , , Represents the impedance of three different loads.

[0075] In the embodiments of the present application, Figure 2 As shown, the specific operation of obtaining the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system can be:

[0076] ,

[0077] ,

[0078] in, It indicates the fault current value upstream of the grid connection point voltage after the inverter interface distributed power source is connected to the power system. The fault current value downstream of the grid connection point voltage after the inverter interface distributed power source is connected to the power system, Indicates the access current of the inverter interface distributed power supply.

[0079] In the embodiments of the present application, Figure 2 As shown, according to the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system, the grid connection point voltage value after the inverter interface distributed power source is connected to the power system can be calculated as:

[0080] ,

[0081] in, Indicates the voltage value of the grid connection point after the inverter interface distributed generation is connected to the power system.

[0082] It should be noted that the solution can also be performed according to the traditional calculation method. The traditional synchronous power supply network can be decomposed into a normal operating network and a fault component network after a short circuit fault occurs. First, the voltage of each node under normal conditions is obtained by using the power flow calculation, which is the normal component; then, all power supplies are grounded, and a reverse power supply is added to the fault point, with the direction from the short circuit point to the ground, so as to calculate the fault component of the voltage of each node. The normal component and the fault component are superimposed to obtain the voltage distribution of the network during the short circuit, and thus the current distribution of the entire network can be obtained.

[0083] Furthermore, performing the first inverter interface distributed power supply partition according to the preset first off-grid judgment logic includes: preferentially partitioning the topological node model, and recording the partitioned topological node model as a fault partition and a non-fault partition;

[0084] When the grid connection point voltage value of a certain inverter interface distributed power source is less than the first grid connection threshold after it is connected to the power system, it is recorded as the inverter interface distributed power source is within the first partition range;

[0085] When the grid connection point voltage value of a certain inverter interface distributed power source is not less than the first grid connection threshold value and not greater than the second threshold value after the inverter interface distributed power source is connected to the power system, and the inverter interface distributed power source is located in the fault zone, the inverter interface distributed power source is recorded as being within the second zone range;

[0086] When a certain inverter-type interface distributed power source is connected to the power system, the grid connection point voltage value is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter-type interface distributed power source is located in a non-fault partition, it is recorded that the inverter-type interface distributed power source is within the third partition range;

[0087] When the voltage value of the grid connection point of a certain inverter-type interface distributed power source is not less than the second grid connection threshold after it is connected to the power system, it is recorded that the inverter-type interface distributed power source is within the fourth zone.

[0088] In the embodiment of the present application, the first grid-connected threshold is 0.2pu, and the second grid-connected threshold is 0.9pu. The acquisition of these thresholds is implemented using the above operations:

[0089] Step 1: Obtain the detailed topology of the power grid, including parameters of transformers, lines, loads, generators, etc. Determine potential distributed generation (DG) access points and their expected maximum output power.

[0090] Use power system simulation software (such as PSCAD, MATLAB / Simulink with Power System Toolbox, DIgSILENT PowerFactory, etc.) to build a dynamic model of the power grid, including the DG model. Various operating conditions should be considered in the model, such as different load levels, the status of existing power generation resources, etc.

[0091] Step 2: Conduct preliminary simulations to calculate the power flow of the power grid without DG access, record the voltage levels at key nodes (especially the expected DG access nodes), analyze the system's response to load changes, and identify voltage-sensitive areas.

[0092] Step 3: Determine the grid connection threshold, gradually increase the DG power simulation, gradually increase the DG output power from zero, perform power flow calculation after each increase, and observe the voltage change at the grid connection point. Record the voltage value corresponding to the DG output power when the voltage begins to drop significantly (the critical point that may cause voltage instability or service quality degradation), which will be the candidate value of the first grid connection threshold.

[0093] Continue to increase the power and find the point where the voltage is close to but does not exceed the upper limit of the normal working range (usually around 1.0pu of the nominal voltage, but not more than 1.1pu to avoid overvoltage problems). The voltage value corresponding to the DG power at this time can be used as a reference for the second grid-connected threshold.

[0094] Step 4: Repeat step 3 for different load levels and system fault conditions to ensure that the selected threshold has broad applicability and robustness. Consider seasonal load changes, extreme weather events, etc., conduct sensitivity analysis and fine-tune the threshold.

[0095] Step 5: Experimental DG access can be carried out in a small area of ​​the actual power grid to verify the accuracy of the simulation results.

[0096] Step 6: Combine the simulation results with the actual grid operation experience to determine the final first grid connection threshold (preferably 0.2pu) and second grid connection threshold (preferably 0.9pu). Ensure that the selected thresholds meet the grid stability and security requirements and fully utilize the potential of DG.

[0097] In the embodiment of the present application, when the grid connection point voltage value is <0.2pu, the grid-off time of the inverter interface distributed power source (IIDG) is 0.15s;

[0098] When the grid connection point voltage value is 0.2-0.9pu, the IIDG off-grid time is 2s;

[0099] When the grid connection point voltage value exceeds 0.9pu, the IIDG will not be disconnected from the grid.

[0100] In an optional embodiment, the first grid-connected threshold and the second grid-connected threshold can also be roughly set based on historical data, or can be set based on expert experience, or can be set based on expert experience combined with different algorithms, or can be set based on other specific experiments, which is not limited here.

[0101] It should be noted that by analyzing and calculating the voltage value of the grid connection point after the inverter-type interface distributed power source is connected to the power system, and partitioning based on the preset first off-grid judgment logic, the following benefits can be achieved:

[0102] First, by calculating the fault current values ​​upstream and downstream of the grid connection point voltage, the impact of the inverter-type interface distributed power generation on the voltage distribution of the entire system after it is connected to the power system can be accurately evaluated. This helps to understand the potential impact of distributed power generation access on the voltage stability and power quality of the power grid, thereby ensuring the safe and stable operation of the power system.

[0103] Secondly, according to the preset first off-grid judgment logic, the inverter-type interface distributed power source can be classified and managed according to different voltage ranges. In this way, when a fault or abnormal situation occurs, corresponding control strategies can be adopted according to different partition situations, such as priority off-grid, delayed off-grid or no off-grid, so as to maximize the stability and reliability of the power system.

[0104] In addition, by setting the first grid connection threshold and the second grid connection threshold, it can be flexibly adjusted according to the actual operation and needs of the power grid. The setting of these thresholds can be based on a variety of methods such as simulation analysis, historical data, and expert experience to ensure their accuracy and applicability. In this way, it can better meet the needs of distributed power generation access to the power system in different scenarios and improve the intelligence and adaptability of the power grid.

[0105] In summary, step S102 provides an effective means for access and management of inverter-type interface distributed power sources through precise calculation and logical partitioning, which helps to ensure the safe and stable operation of the power system and improve the power quality.

[0106] S103, performing equivalent calculation on the partitioned inverter interface distributed power sources, and disconnecting the inverter interface distributed power sources that meet the disconnection requirements in the first disconnection judgment logic according to the calculation results combined with the first disconnection judgment logic;

[0107] Among them, performing equivalent calculation on the partitioned inverter interface distributed power supply includes: performing equivalent calculation on the inverter interface distributed power supply within the first partition range, the second partition range, the third partition range and the fourth partition range according to a preset equivalent logic.

[0108] In the embodiment of the present application, when the grid connection point voltage value of a certain inverter interface distributed power source is less than 0.2pu after it is connected to the power system, it is recorded as the inverter interface distributed power source is within the first partition range;

[0109] When the grid connection point voltage value of a certain inverter interface distributed power source is not less than 0.2pu and not more than 0.9pu after it is connected to the power system, and the inverter interface distributed power source is located in the fault zone, it is recorded as the inverter interface distributed power source is within the second zone;

[0110] When the grid connection point voltage value of a certain inverter interface distributed power source is not less than 0.2pu and not more than 0.9pu after it is connected to the power system, and the inverter interface distributed power source is located in a non-fault partition, it is recorded as the inverter interface distributed power source is within the third partition;

[0111] When the grid connection point voltage value of a certain inverter-type interface distributed power source is not less than 0.9pu after it is connected to the power system, it is recorded as the inverter-type interface distributed power source is within the fourth zone.

[0112] like Figure 3 As shown, line LM is a non-fault area, line MN is a fault area, in the figure, ① is the fourth partition range, ② is the third partition range, ③ is the second partition range, ④ is the first partition range, and all inverter interface distributed power sources within the first partition range in the first inverter interface distributed power source partition are disconnected from the grid. The probability of all inverter interface distributed power sources within the first partition range in the first inverter interface distributed power source partition being disconnected from the grid is 100%, but since the original line data will change after each disconnection operation, the second inverter interface distributed power source partition, the third inverter interface distributed power source partition, ..., the Nth inverter interface distributed power source partition have a probability of disconnecting from the grid. The probability of all inverter-type interface distributed power sources within a partition being disconnected from the grid is reduced according to a fixed step size, which can be determined based on the ratio of the capacity of all inverter-type interface distributed power sources within the first partition range in the first inverter-type interface distributed power source partition to the capacity of all inverter-type interface distributed power sources on the line LN. If the ratio is less than the first proportion threshold, the selected fixed step size can be 5%. In this application, the first proportion threshold is generally 0.1. If the ratio is greater than the second proportion threshold, the selected fixed step size can be 1%. In this application, the second proportion threshold is generally 0.4, until finally after the disconnection, only inverter-type interface distributed power sources in the fourth partition range and the non-fault area of ​​the third partition range exist.

[0113] When a partition does not include the first partition range after the off-grid operation is performed, the off-grid operation is started for the inverter interface distributed power supply within the second partition range, and the probability of all the inverter interface distributed power supplies within the second partition range being off-grid is not less than the probability of all the inverter interface distributed power supplies within the first partition range being off-grid for the last time. In this application, the probability of all the inverter interface distributed power supplies within the second partition range being off-grid is equal to the probability of all the inverter interface distributed power supplies within the first partition range being off-grid for the last time. For example, when the inverter interface distributed power supplies within the first partition range are off-grid in different rounds, the probability of off-grid operation is 80%, then the probability of off-grid operation for all the inverter interface distributed power supplies within the second partition range next time is at least 80%;

[0114] After the final disconnection from the grid, only inverter-type interface distributed power sources exist within the fourth zone and the non-fault area within the third zone.

[0115] In the embodiment of the present application, the equivalent calculation of the partitioned inverter interface distributed power supply is to calculate the capacity and position of the equivalent inverter interface distributed power supply. In the present application, all the inverter interface distributed power supplies on the line LN are divided into ①, ②, ③, and ④ according to the partition results. Therefore, the equivalent capacity in each partition result can be directly obtained, which can be calculated by the following formula, such as Figure 3 As shown:

[0116] ,

[0117] Wherein, j represents the jth equivalent inverter interface distributed power source, j=1,2,3,4; n represents that there are n inverter interface distributed power sources equivalent to the jth equivalent inverter interface distributed power source. The access position of the jth equivalent inverter interface distributed power source is the first and last inverter interface distributed power source access position x among the n inverter interface distributed power sources. 1 and x n The average value of x j =(x 1 +x n ) / 2;

[0118] In an optional embodiment, the equivalent calculation of the partitioned inverter interface distributed power source can also be obtained through weighted operations. Since the location of the distributed power source has different effects on the system voltage, the power source close to the load center or the weak link of the power grid has a greater influence. The location weight can be determined based on the distance between its access location and certain key nodes (such as the load center, voltage support point) or the inverse of the system impedance, the capacity weight factor can be set, and a comprehensive weight calculation method can be established based on the above operations to achieve the final capacity and location determination. The specific operations can be as follows:

[0119] Step 1: Position weight factor :Due to the different influences of the location of distributed power sources on the system voltage, the power sources close to the load center or the weak link of the power grid have a greater influence. The location weight can be determined based on the distance between its access location and certain key nodes (such as the load center, voltage support point) or the inverse of the system impedance. For example:

[0120] ,

[0121] in, is the distance from the jth inverter interface distributed generation access point to the key node.

[0122] Capacity Weight Factor :It is set directly according to the rated power or actual output power of the inverter, reflecting its contribution to the system energy. It can be simply defined as ,in is the power of the jth inverter interface distributed generation.

[0123] Step 2: Calculate the comprehensive weight and record the comprehensive weight factor:

[0124] ,

[0125] in, It is a coefficient between 0 and 1, which is used to balance the importance of location factors and capacity factors. Adjust according to system characteristics If you pay more attention to the geographical location, increase ; if more emphasis is placed on capacity contribution, reduce .

[0126] Step 3: Calculate equivalent capacity. Use weighted average method to calculate equivalent capacity. For n inverter-type interface distributed power sources in the ith partition, the equivalent capacity is The calculation formula becomes:

[0127] ,

[0128] in, is the capacity of the i-th inverter interface distributed generation, is the corresponding comprehensive weight factor.

[0129] Step 4: Calculation of equivalent position. The calculation of equivalent position still uses the average position method, but the weight factor can be further considered. Although the equivalence of position usually depends more on the physical layout than the weight:

[0130] ,

[0131] here, is the access location of the i-th inverter interface distributed generation, is its position weight factor.

[0132] In an optional embodiment, the equivalent calculation of the partitioned inverter-type interface distributed power source may also be calculated by other methods, which are not limited in this application.

[0133] It should be noted that by partitioning and equivalently calculating the inverter-type interface distributed power sources, the subsequent calculation and analysis process can be greatly simplified. Dividing the large number of widely distributed inverter-type interface distributed power sources into several areas according to certain rules and performing equivalent processing on each area can significantly reduce the amount of data to be processed and improve calculation efficiency.

[0134] Equivalent calculations retain key information while ignoring minor details. By calculating the equivalent capacity and location of each partition, the key points that have the greatest impact on the system can be obtained without paying attention to the specific details of each inverter-type interface distributed power source. This helps to more clearly understand the impact of distributed power sources on the system and provide strong support for subsequent optimization and control strategies.

[0135] According to the ratio of the capacity of the inverter-type interface distributed power supply in different partitions to the total capacity of the line, different fixed step sizes are selected for off-grid operation, which can ensure that the impact of off-grid operation on the system is minimized while ensuring the stable operation of the system. This design takes into account both the safety of the system and its economy and practicality.

[0136] S104, obtaining the grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation, performing a second inverter interface distributed power source partitioning according to a preset first off-grid judgment logic, and performing an off-grid operation.

[0137] Among them, performing the second inverter interface distributed power source partitioning according to the preset first off-grid judgment logic includes: obtaining the upstream and downstream fault current values ​​of the voltage of the remaining different inverter interface distributed power sources before access to the grid after the off-grid operation;

[0138] Furthermore, the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system are obtained;

[0139] Furthermore, the grid connection point voltage value after the inverter interface distributed power source is connected to the power system after the off-grid operation is performed is calculated based on the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system.

[0140] Furthermore, performing equivalent calculation on the inverter interface distributed power source after the second partition, and disconnecting the inverter interface distributed power source that meets the disconnection requirement in the first disconnection judgment logic according to the calculation result in combination with the first disconnection judgment logic includes:

[0141] When the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is less than the first grid connection threshold, the inverter interface distributed power source is recorded as being within the first partition range;

[0142] Furthermore, when the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter interface distributed power source is located in the fault partition, it is recorded as the inverter interface distributed power source is within the second partition range;

[0143] Furthermore, when a grid-connected point voltage value of a certain inverter-type interface distributed power source after being connected to the power system after the off-grid operation is performed is not less than the first grid-connected threshold value and not greater than the second threshold value, and the inverter-type interface distributed power source is located in a non-fault partition, it is recorded that the inverter-type interface distributed power source is within the third partition range;

[0144] Furthermore, when the voltage value of the grid connection point after a certain inverter-type interface distributed power source is connected to the power system after the off-grid operation is performed is not less than the second grid connection threshold, the inverter-type interface distributed power source is recorded as being within the fourth zone.

[0145] Furthermore, a second inverter interface distributed power source partition is performed according to a preset first off-grid judgment logic;

[0146] Furthermore, an equivalent calculation is performed on the inverter-type interface distributed power source after the second partition, and the inverter-type interface distributed power source that meets the off-grid requirement in the first off-grid judgment logic is off-grid according to the calculation result combined with the first off-grid judgment logic;

[0147] Furthermore, the grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation are obtained, and the third inverter interface distributed power source partition is performed according to the preset first off-grid judgment logic, and the off-grid operation is performed;

[0148] Furthermore, the off-grid and partitioning operations are repeated until all the inverter-type interface distributed power sources on the non-fault lines are not off-grid and all the inverter-type interface distributed power sources on the faulty lines are off-grid, the number of inverter-type interface distributed power sources that are off-grid is obtained, and the possibility is evaluated.

[0149] In the embodiment of the present application, by obtaining the capacity values ​​of all inverter interface distributed power sources within the first partition range of the first inverter interface distributed power source partition, the capacity values ​​of all inverter interface distributed power sources within the second partition range, the capacity values ​​of all inverter interface distributed power sources within the third partition range, and the capacity values ​​of all inverter interface distributed power sources within the fourth partition range, as well as the total capacity value of all inverter interface distributed power sources that are completely disconnected from the grid after being completely disconnected, the proportion of off-grid capacity in different areas is determined, and the possibility of off-grid of the inverter interface distributed power source is evaluated according to the off-grid proportion;

[0150] Specifically, according to the above formula for calculating capacity, the total capacity value of the inverter interface distributed power supply within the first partition can be obtained: , the total capacity value of the inverter interface distributed power supply within the second zone , the total capacity value of the inverter interface distributed power supply within the third zone , the total capacity value of inverter interface distributed power supply within the fourth zone , according to the total capacity value of all off-grid inverter interface distributed power sources after complete off-grid disconnection ;

[0151] In the embodiment of the present application, different evaluation levels can be formulated based on the proportion of off-grid capacity. For example, if the proportion of off-grid capacity in a certain partition is very high, it means that the inverter-type interface distributed power source in the area is more likely to be off-grid under certain conditions, which may be because the grid structure, voltage control capability or inverter setting in the area are relatively fragile.

[0152] In an embodiment of the present application, a threshold value can be set. For example, in non-fault lines, a proportion of more than 30% is considered to be a "high risk" area, 10%-30% is a "medium risk", and less than 10% is a "low risk". In fault lines, a proportion of more than 30% is considered to be a "low risk" area, 10%-30% is a "medium risk", and less than 10% is a "high risk".

[0153] In an optional embodiment, the specific reasons for the identified high-risk areas may be further analyzed, such as whether the voltage control strategy in the area is not flexible enough or the low voltage ride-through capability of the inverter is insufficient.

[0154] In an optional embodiment, improvement measures can also be proposed based on the analysis results, such as optimizing the inverter control strategy, enhancing the local voltage support capability of the power grid, or adjusting the layout and access strategy of the inverter-type interface distributed power source to reduce the possibility of future disconnection from the grid.

[0155] In an optional embodiment, the risk status can also be directly judged by the offline capacity, low risk: the actual offline capacity is less than the first offline threshold or the predicted offline capacity is less than the first offline threshold, medium risk: the actual / predicted offline capacity is not less than the first offline threshold and less than the second offline threshold, high risk: the actual offline capacity is not less than the second offline threshold or the predicted offline capacity is not less than the second offline threshold.

[0156] This embodiment also provides a large-scale inverter-type interface distributed power supply off-grid possibility evaluation system, including:

[0157] A model building module is used to obtain the structural parameters and data parameters of the target power system after the inverter interface distributed power source is connected, and to build a topological node model including the data parameters according to the structural parameters and the data parameters;

[0158] A partitioning module, used to calculate the grid connection point voltages of different inverter interface distributed power sources according to a topological node model containing data parameters, and perform a first inverter interface distributed power source partition according to a preset first off-grid judgment logic;

[0159] The off-grid judgment module is used to perform equivalent calculation on the inverter-type interface distributed power source after partitioning, and to disconnect the inverter-type interface distributed power source that meets the off-grid requirement in the first off-grid judgment logic according to the calculation result combined with the first off-grid judgment logic;

[0160] The off-grid operation module is used to obtain the grid connection point voltages of the remaining different inverter-type interface distributed power sources after the off-grid operation, and to perform a second inverter-type interface distributed power source partition according to the preset first off-grid judgment logic, and to perform the off-grid operation.

[0161] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0162] This embodiment also provides a computer device, which may be a terminal, and its internal structure diagram may be as shown in FIG. Figure 4As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0163] This embodiment further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0164] Obtaining structural parameters and data parameters of the target power system after connecting to the inverter interface distributed power source, and establishing a topological node model including the data parameters according to the structural parameters and the data parameters;

[0165] Calculate the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing data parameters, and perform the first inverter interface distributed power source partitioning according to the preset first off-grid judgment logic;

[0166] Perform equivalent calculation on the partitioned inverter interface distributed power sources, and disconnect the inverter interface distributed power sources that meet the disconnection requirements in the first disconnection judgment logic according to the calculation results combined with the first disconnection judgment logic;

[0167] The grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation are obtained, and the second inverter interface distributed power source partition is performed according to the preset first off-grid judgment logic, and the off-grid operation is performed.

[0168] Example 2, reference Figure 1-Figure 4 , which is an embodiment of the present invention, provides a method and system for evaluating the possibility of off-grid disconnection of a large-scale inverter-type interface distributed power source. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0169] In this embodiment, the accuracy and effectiveness of the off-grid possibility evaluation method are further verified. To achieve this, an actual operating power system is selected as the test object, which contains a large number of inverter-type interface distributed power sources. First, the power system is modeled according to the above method, and partitions and off-grid judgments are performed based on the model. Then, the actual operation data is compared with the model prediction results to verify the accuracy of the method.

[0170] Table 1: Comparison of actual operation data and model predictions.

[0171] ,

[0172] ,

[0173] The consistency of risk level assessment lists the degree of agreement between the risk level predicted by the model and the actual operating conditions, with √ indicating agreement and × indicating deviation.

[0174] Table 2: Computational efficiency evaluation table.

[0175] ,

[0176] The experimental results show that the present invention can accurately predict the possibility of disconnection of inverter-type interface distributed power sources, and the zoning results are consistent with the actual situation. Through the present invention, potential high-risk areas can be discovered in time, and corresponding improvement measures can be formulated, thereby improving the stability and reliability of the power system.

[0177] In addition, the computational efficiency of the present invention is evaluated. The experimental results show that the present invention exhibits good performance in terms of computational speed and resource consumption, and can meet the real-time evaluation requirements of large-scale power systems.

[0178] In summary, the large-scale inverter-type interface distributed power supply disconnection possibility evaluation method and system provided by this embodiment have high accuracy and effectiveness, which is of great significance for improving the safety and stability of the power system. At the same time, the method has high computational efficiency and is suitable for real-time evaluation of large-scale power systems.

[0179] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0180] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present application may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0181] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0182] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0183] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0184] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0185] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid, characterized in that: include: Acquire structural parameters and data parameters of the target power system after connecting to the inverter interface distributed power source, and establish a topological node model including the data parameters according to the structural parameters and data parameters; Calculating the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing the data parameters, and performing the first inverter interface distributed power source partitioning according to the preset first off-grid judgment logic; Perform equivalent calculation on the inverter-type interface distributed power sources after partitioning, and disconnect the inverter-type interface distributed power sources that meet the disconnection requirements in the first disconnection judgment logic according to the calculation results combined with the first disconnection judgment logic; Obtaining the grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation, performing a second inverter interface distributed power source partition according to the preset first off-grid judgment logic, and performing the off-grid operation; Performing a second inverter interface distributed power generation partition according to a preset first off-grid judgment logic; Perform equivalent calculation on the inverter-type interface distributed power source after the second partition, and disconnect the inverter-type interface distributed power source that meets the disconnection requirement in the first disconnection judgment logic according to the calculation result and the first disconnection judgment logic; Obtaining the grid connection point voltages of the remaining distributed power sources with different inverter interfaces after the off-grid operation, performing a third inverter interface distributed power partition according to the preset first off-grid judgment logic, and performing the off-grid operation; Repeat the off-grid and partition operations until all the inverter-type interface distributed power sources on the non-fault lines are not off-grid and all the inverter-type interface distributed power sources on the faulty lines are off-grid, obtain the number of inverter-type interface distributed power sources that are off-grid, and conduct a possibility evaluation; The step of calculating the grid connection point voltage of distributed power sources with different inverter interfaces according to the topological node model containing data parameters includes: Obtain the upstream and downstream fault current values ​​of the grid connection point voltage before a certain inverter-type interface distributed power source is connected; Obtaining the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system; Calculate the grid connection point voltage value after the inverter interface distributed power source is connected to the power system according to the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system; The first inverter interface distributed power source partitioning according to the preset first off-grid judgment logic includes: Prioritizing partitioning of the topological node model, and recording the partitioned topological node model as a fault partition and a non-fault partition; When the grid connection point voltage value of a certain inverter interface distributed power source is less than the first grid connection threshold after it is connected to the power system, it is recorded as the inverter interface distributed power source is within the first partition range; When the grid connection point voltage value of a certain inverter interface distributed power source is not less than the first grid connection threshold value and not greater than the second threshold value after the inverter interface distributed power source is connected to the power system, and the inverter interface distributed power source is located in the fault zone, the inverter interface distributed power source is recorded as being within the second zone range; When a certain inverter interface distributed power source is connected to the power system, the grid connection point voltage value is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter interface distributed power source is located in a non-fault partition, it is recorded that the inverter interface distributed power source is within the third partition range; When the voltage value of the grid connection point of a certain inverter-type interface distributed power source is not less than the second grid connection threshold after it is connected to the power system, it is recorded that the inverter-type interface distributed power source is within the fourth zone.

2. The method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid as claimed in claim 1, characterized in that: The performing equivalent calculation on the partitioned inverter interface distributed power sources includes: performing equivalent calculation on the inverter interface distributed power sources within the first partition range, the second partition range, the third partition range, and the fourth partition range according to a preset equivalent logic.

3. The method for evaluating the possibility of large-scale inverter-type interface distributed power sources being disconnected from the grid as claimed in claim 2, characterized in that: The second inverter interface distributed power supply partitioning according to the preset first off-grid judgment logic includes: Obtain the upstream and downstream fault current values ​​of the grid connection point voltage before the remaining distributed power sources with different inverter interfaces are connected after the off-grid operation; Obtaining the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system; The grid connection point voltage value after the inverter interface distributed power source is connected to the power system after the off-grid operation is performed is calculated based on the upstream and downstream fault current values ​​of the grid connection point voltage before the inverter interface distributed power source is connected and the upstream and downstream fault current values ​​of the grid connection point voltage after the inverter interface distributed power source is connected to the power system.

4. The method for evaluating the possibility of large-scale inverter-type interface distributed power supply being disconnected from the grid as claimed in claim 3, characterized in that: The equivalent calculation is performed on the inverter interface distributed power source after the second partition, and the inverter interface distributed power source that meets the off-grid requirement in the first off-grid judgment logic is disconnected from the grid according to the calculation result and the first off-grid judgment logic, including: When the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is less than the first grid connection threshold, the inverter interface distributed power source is recorded as being within the first partition range; When the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter interface distributed power source is located in the fault partition, the inverter interface distributed power source is recorded as being within the second partition range; When the grid connection point voltage value of a certain inverter interface distributed power source after being connected to the power system after the off-grid operation is not less than the first grid connection threshold value and not greater than the second threshold value, and the inverter interface distributed power source is located in a non-fault partition, it is recorded that the inverter interface distributed power source is within the third partition range; When the voltage value of the grid connection point after a certain inverter-type interface distributed power source is connected to the power system after the off-grid operation is performed is not less than the second grid connection threshold, the inverter-type interface distributed power source is recorded as being within the fourth zone.

5. A large-scale inverter interface distributed power supply off-grid possibility evaluation system, based on the large-scale inverter interface distributed power supply off-grid possibility evaluation method according to any one of claims 1 to 4, characterized in that: include: A model building module, used to obtain structural parameters and data parameters of the target power system after connecting to the inverter interface distributed power source, and to build a topological node model including the data parameters according to the structural parameters and data parameters; A partitioning module, used to calculate the grid connection point voltages of different inverter interface distributed power sources according to the topological node model containing data parameters, and perform the first inverter interface distributed power source partitioning according to a preset first off-grid judgment logic; The off-grid judgment module is used to perform equivalent calculation on the inverter-type interface distributed power source after partitioning, and to disconnect the inverter-type interface distributed power source that meets the off-grid requirement in the first off-grid judgment logic according to the calculation result combined with the first off-grid judgment logic; The off-grid operation module is used to obtain the grid connection point voltages of the remaining different inverter-type interface distributed power sources after the off-grid operation, and to perform a second inverter-type interface distributed power source partition according to the preset first off-grid judgment logic, and to perform the off-grid operation.

6. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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