Photovoltaic system anti-islanding performance detection method and device

Abstract

The present invention relates to a method and device for detecting the anti-islanding performance of a photovoltaic system, comprising: connecting simulation models corresponding to respective photovoltaic inverters in parallel, and performing anti-islanding simulation on the parallel-connected models; and determining whether the anti-islanding performance of the photovoltaic system is qualified based on the anti-islanding simulation results of the parallel-connected models. The present invention realizes the anti-islanding performance detection of the entire photovoltaic system based on the simulation models corresponding to the respective photovoltaic inverters, thereby solving the problem in the prior art that the anti-islanding performance detection of the entire photovoltaic system cannot be performed due to the capacity limitation of the test device.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy grid-connected detection technology, and in particular to a method and device for detecting anti-islanding performance of a photovoltaic system. Background Art

[0002] In a photovoltaic system, the generator is connected to the grid and local loads via an inverter. If a fault occurs in the external grid, the grid-connected inverter will disconnect from the grid. To prevent islanding, grid-connected photovoltaic inverters must be equipped with anti-islanding protection. Because islanding can be very harmful, it is particularly important to test the inverter's anti-islanding performance.

[0003] Currently, the anti-islanding performance test of photovoltaic power generation systems is mostly conducted on a single inverter according to relevant standards. However, the active anti-islanding detection method used by inverters in photovoltaic power generation systems is mostly positive feedback control. When multiple machines are connected in parallel, the positive feedback method is not linearly related to the positive feedback method of a single machine. The anti-islanding performance of multiple machines will interfere with each other. Therefore, the sampling results of a single machine cannot represent the test results of multiple machines.

[0004] In addition, in actual working conditions, the capacity of anti-islanding test equipment is limited and cannot meet the requirements of all distributed photovoltaic power generation systems. In addition, the access points of photovoltaic power generation systems are not equipped with dedicated switching devices. Without affecting the user load, the multiple inverters connected in parallel in the photovoltaic power generation system do not have a unified grid disconnection switch device, making it impossible to carry out anti-islanding capability testing. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method and device for detecting the anti-islanding performance of a photovoltaic system, which can realize the overall anti-islanding performance detection of the photovoltaic system by establishing a simulation model of the photovoltaic system.

[0006] The present invention provides a method for detecting anti-islanding performance of a photovoltaic system, wherein the method comprises:

[0007] The simulation models corresponding to each photovoltaic inverter are connected in parallel, and anti-islanding simulation is performed on the parallel models;

[0008] Whether the anti-islanding performance of the photovoltaic system is qualified is determined based on the anti-islanding simulation results of the parallel model.

[0009] Preferably, before connecting the simulation models corresponding to the photovoltaic inverters in parallel, the method includes:

[0010] Perform anti-islanding simulation on the simulation model corresponding to each photovoltaic inverter;

[0011] Performing model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter to obtain a model verification result;

[0012] Adjust the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified until the model verification is qualified.

[0013] Furthermore, the simulation model corresponding to each photovoltaic inverter is verified based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter to obtain the model verification result, including:

[0014] The root mean square error F between the simulated data and the measured data of the grid connection point in the anti-islanding simulation results of the i-th photovoltaic inverter is calculated as follows: i,err :

[0015]

[0016] Where, F i,f_start is the grid connection point simulation data corresponding to the simulation start time in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,f_end is the grid connection point simulation data corresponding to the end of the simulation in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,s_start is the measured data of the grid connection point corresponding to the starting time of the simulation of the i-th photovoltaic inverter, F i,s_end is the measured data of the grid connection point corresponding to the end of the simulation of the i-th photovoltaic inverter;

[0017] If F i,err If the value is less than the preset value, the verification result of the simulation model corresponding to the i-th photovoltaic inverter is qualified, otherwise it is unqualified;

[0018] Where i∈[1,N], N is the total number of PV inverters.

[0019] Furthermore, the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified is adjusted, including:

[0020] Obtain the curvature k of the grid connection point simulation data curve of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified f The curvature k of the measured data curve of the grid connection point of each photovoltaic inverter whose model verification result is unqualified s ;

[0021] If k f ≥k s , the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is reduced according to the preset step size; otherwise, the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is increased according to the preset step size.

[0022] Preferably, determining whether the anti-islanding performance of the photovoltaic system is qualified according to the anti-islanding simulation results of the parallel-connected models includes:

[0023] If the maximum value of the photovoltaic inverter tripping time in the anti-islanding simulation result of the parallel model is greater than the preset tripping time, the test result of the photovoltaic system anti-islanding performance is qualified, otherwise it is unqualified.

[0024] Based on the same inventive concept, the present invention also provides a photovoltaic system anti-islanding performance detection device, the improvement of which is that the device includes:

[0025] The simulation unit is used to connect the simulation models corresponding to the photovoltaic inverters in parallel and perform anti-islanding simulation on the parallel models;

[0026] The detection unit is used to determine whether the anti-islanding performance of the photovoltaic system is qualified according to the anti-islanding simulation results of the parallel model.

[0027] Preferably, the device further comprises:

[0028] The simulation subunit is used to perform anti-islanding simulation on the simulation model corresponding to each photovoltaic inverter;

[0029] a verification unit, configured to perform model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter, and obtain a model verification result;

[0030] The adjustment unit is used to adjust the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified until the model verification is qualified.

[0031] Furthermore, the verification unit is specifically used to:

[0032] The root mean square error F between the simulated data and the measured data of the grid connection point in the anti-islanding simulation results of the i-th photovoltaic inverter is calculated as follows: i,err :

[0033]

[0034] Where, F i,f_start is the grid connection point simulation data corresponding to the simulation start time in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,f_end is the grid connection point simulation data corresponding to the end of the simulation in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,s_start is the measured data of the grid connection point corresponding to the starting time of the simulation of the i-th photovoltaic inverter, F i,s_end is the measured data of the grid connection point corresponding to the end of the simulation of the i-th photovoltaic inverter;

[0035] If F i,err If the value is less than the preset value, the verification result of the simulation model corresponding to the i-th photovoltaic inverter is qualified, otherwise it is unqualified;

[0036] Where i∈[1,N], N is the total number of PV inverters.

[0037] Furthermore, the adjustment unit is specifically configured to:

[0038] Obtain the curvature k of the grid connection point simulation data curve of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified f The curvature k of the measured data curve of the grid connection point of each photovoltaic inverter whose model verification result is unqualified s ;

[0039] If k f ≥k s , the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is reduced according to the preset step size; otherwise, the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is increased according to the preset step size.

[0040] Preferably, the detection unit is specifically used to:

[0041] If the maximum value of the photovoltaic inverter tripping time in the anti-islanding simulation result of the parallel model is greater than the preset tripping time, the test result of the photovoltaic system anti-islanding performance is qualified, otherwise it is unqualified.

[0042] Compared with the closest prior art, the present invention has the following beneficial effects:

[0043] The present invention provides a method and device for detecting the anti-islanding performance of a photovoltaic system. The method connects simulation models corresponding to each photovoltaic inverter in parallel, performs anti-islanding simulation on the paralleled models, and determines whether the anti-islanding performance of the photovoltaic system is qualified based on the anti-islanding simulation results of the paralleled models. The present invention detects the anti-islanding performance of the photovoltaic system as a whole based on the simulation models corresponding to each photovoltaic inverter, solving the problem in the prior art that the anti-islanding performance of the photovoltaic system as a whole cannot be detected due to the limited capacity of the test device. At the same time, it avoids the problem that the sampling results of a single machine cannot represent the detection results of multiple machines.

[0044] Among them, before the simulation models corresponding to the photovoltaic inverters are connected in parallel, the simulation models corresponding to the photovoltaic inverters are simulated first, and then the simulation models are verified based on the simulation results. Finally, the parameters of the models that fail the verification are adjusted to improve the accuracy of the models. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a flow chart of the photovoltaic system anti-islanding performance detection method of the present invention;

[0046] Figure 2 It is a schematic diagram of the photovoltaic system anti-islanding performance detection device of the present invention. DETAILED DESCRIPTION

[0047] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0049] The present invention provides a method for detecting the anti-islanding performance of a photovoltaic system. Figure 1 As shown, the method includes:

[0050] The simulation models corresponding to each photovoltaic inverter are connected in parallel, and anti-islanding simulation is performed on the parallel models;

[0051] Whether the anti-islanding performance of the photovoltaic system is qualified is determined based on the anti-islanding simulation results of the parallel model.

[0052] In order to more clearly illustrate the purpose of the present invention, the scheme of the present invention is further described below in conjunction with specific embodiments.

[0053] In an embodiment of the present invention, before connecting the simulation models corresponding to the photovoltaic inverters in parallel, the method includes:

[0054] Perform anti-islanding simulation on the simulation model corresponding to each photovoltaic inverter;

[0055] Performing model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter to obtain a model verification result;

[0056] Adjust the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified until the model verification is qualified.

[0057] The simulation model corresponding to each photovoltaic inverter is a model built according to the actual main circuit and control circuit structure of each photovoltaic inverter.

[0058] Specifically, the above-mentioned model verification is performed on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter to obtain the model verification result, including:

[0059] The root mean square error F between the simulated data and the measured data of the grid connection point in the anti-islanding simulation results of the i-th photovoltaic inverter is calculated as follows: i,err :

[0060]

[0061] Where, F i,f_start is the grid connection point simulation data corresponding to the simulation start time in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,f_end is the grid connection point simulation data corresponding to the end of the simulation in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,s_start is the measured data of the grid connection point corresponding to the starting time of the simulation of the i-th photovoltaic inverter, F i,s_end is the measured data of the grid-connected point corresponding to the end of the simulation of the i-th photovoltaic inverter; wherein the grid-connected point data includes the voltage, current or frequency of the grid-connected point. In the embodiment of the present invention, the frequency of the grid-connected point is used as the basis for judgment.

[0062] If F i,err If the value is less than the preset value, the verification result of the simulation model corresponding to the i-th photovoltaic inverter is qualified, otherwise it is unqualified;

[0063] Where i∈[1,N], N is the total number of PV inverters.

[0064] In the embodiment of the present invention, a 3MW photovoltaic system is selected. In this system, there are two photovoltaic inverters of three types, as shown in Table 1:

[0065] Table 1 Anti-islanding protection algorithms corresponding to three inverters

[0066] Inverter model Anti-islanding protection algorithm adopted Inverter A Active frequency shift method Inverter B Active phase shift method Inverter C Reactive disturbance method

[0067] And the anti-islanding test conditions given in Table 2 are tested to verify whether the model is qualified, and the frequency preset value is set to 0.1 Hz;

[0068] Table 2 Anti-islanding capability test conditions

[0069]

[0070]

[0071] When inverter A is running at rated power, the three operating conditions shown in Table 2 are tested. By comparing the simulated and measured frequencies at the grid connection point, we find that:

[0072] 1) When the RLC load is fully matched, the anti-islanding detection time in the type test is 0.296s. The RLC load in the simulation model is consistent with the type test, with an anti-islanding detection time of 0.285s and a root mean square error of 0.049Hz, which meets the error limit requirements.

[0073] 2) When the RLC active load is fully matched and the reactive power flowing through the grid-connected switch is -5% of the nominal load reactive power value when fully matched, the anti-islanding detection time in the type test is 0.135s, and the anti-islanding detection time in the simulation model is 0.138s, with a root mean square error of 0.076Hz, which meets the error limit requirement;

[0074] 3) When the RLC active load is fully matched and the reactive power flowing through the grid-connected switch is 5% of the nominal reactive power value of the load when fully matched, the anti-islanding detection time in the type test is 0.133s, and the anti-islanding detection time in the simulation model is 0.125s, and the root mean square error is 0.033Hz, which meets the error limit requirement;

[0075] To further confirm the accuracy of the model, the rated power was changed and compared multiple times, as shown in Table 3. The analysis found that the error between the simulation results and the measured results of the anti-islanding capability model of inverter A was extremely small, and it can be fully used to evaluate the anti-islanding capability of photovoltaic power generation systems.

[0076] Table 3 Error analysis results of inverter A anti-islanding capability model verification

[0077] Test error (Hz) Test 2 error (Hz) Test three errors (Hz) Weighted error (Hz) 100% rated power 0.049 0.0076 0.033 0.053 60% rated power 0.061 0.014 0.045 0.040 30% rated power 0.074 0.063 0.069 0.069

[0078] Similarly, the verification error analysis results of inverter B and C models can be obtained, as shown in Table 4 and Table 5.

[0079] Table 4. Verification error analysis results of inverter B’s anti-islanding capability model

[0080]

[0081]

[0082] Table 5 Error analysis results of inverter C anti-islanding capability model verification

[0083] Test 1 Test 2 Test Three Weighted 100% rated power 0.030 0.012 0.011 0.018 60% rated power 0.083 0.088 0.039 0.070 30% rated power 0.059 0.012 0.011 0.028

[0084] If the model verification fails, the model needs to be adjusted. The positive feedback coefficients of the simulation models corresponding to the photovoltaic inverters whose model verification results fail are as follows:

[0085] Obtain the curvature k of the grid connection point simulation data curve of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified fThe curvature k of the measured data curve of the grid connection point of each photovoltaic inverter whose model verification result is unqualified s ;

[0086] If k f ≥k s , the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is reduced according to the preset step size. Otherwise, the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is increased according to the preset step size. The preset step size can be set to 1%. The actual value of the step size can be changed according to the specific situation based on the error size.

[0087] In an embodiment of the present invention, the above-mentioned determination of whether the anti-islanding performance of the photovoltaic system is qualified based on the anti-islanding simulation results of the parallel-connected models includes:

[0088] If the maximum value of the photovoltaic inverter tripping time in the anti-islanding simulation result of the parallel model is greater than the preset tripping time, the test result of the photovoltaic system anti-islanding performance is qualified, otherwise it is unqualified.

[0089] In this embodiment, a photovoltaic system simulation model was established based on a model-verified inverter model connected in parallel. Simulation tests of the photovoltaic power generation system's anti-islanding performance were conducted under the nine test conditions listed in Table 2. The test duration ranged from 0.3s to 1.3s, with a maximum duration of 1.3s, which is less than the protection limit of 2s. Therefore, the tested photovoltaic power generation system's anti-islanding protection capability met standard requirements. This invention has broad applicability, and the number of parallel models can be varied for testing as needed.

[0090] Based on the same inventive concept, the present invention also provides a photovoltaic system anti-islanding performance detection device, such as Figure 2 As shown, the device includes:

[0091] The simulation unit is used to connect the simulation models corresponding to the photovoltaic inverters in parallel and perform anti-islanding simulation on the parallel models;

[0092] The detection unit is used to determine whether the anti-islanding performance of the photovoltaic system is qualified according to the anti-islanding simulation results of the parallel model.

[0093] Preferably, the device further comprises:

[0094] The simulation subunit is used to perform anti-islanding simulation on the simulation model corresponding to each photovoltaic inverter;

[0095] a verification unit, configured to perform model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter, and obtain a model verification result;

[0096] The adjustment unit is used to adjust the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified until the model verification is qualified.

[0097] Specifically, the verification unit is used to:

[0098] The root mean square error F between the simulated data and the measured data of the grid connection point in the anti-islanding simulation results of the i-th photovoltaic inverter is calculated as follows: i,err :

[0099]

[0100] Where, F i,f_start is the grid connection point simulation data corresponding to the simulation start time in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,f_end is the grid connection point simulation data corresponding to the end of the simulation in the anti-islanding simulation result of the i-th photovoltaic inverter, F i,s_start is the measured data of the grid connection point corresponding to the starting time of the simulation of the i-th photovoltaic inverter, F i,s_end is the measured data of the grid connection point corresponding to the end of the simulation of the i-th photovoltaic inverter;

[0101] If F i,err If the value is less than the preset value, the verification result of the simulation model corresponding to the i-th photovoltaic inverter is qualified, otherwise it is unqualified;

[0102] Where i∈[1,N], N is the total number of PV inverters.

[0103] Specifically, the adjustment unit is used to:

[0104] Obtain the curvature k of the grid connection point simulation data curve of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified f The curvature k of the measured data curve of the grid connection point of each photovoltaic inverter whose model verification result is unqualified s ;

[0105] If k f ≥k s , the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is reduced according to the preset step size; otherwise, the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is increased according to the preset step size.

[0106] In an embodiment of the present invention, the detection unit is specifically configured to:

[0107] If the maximum value of the photovoltaic inverter tripping time in the anti-islanding simulation result of the parallel model is greater than the preset tripping time, the test result of the photovoltaic system anti-islanding performance is qualified, otherwise it is unqualified.

[0108] In summary, the present invention provides a method and device for detecting the anti-islanding performance of a photovoltaic system. The method connects the simulation models corresponding to the photovoltaic inverters in parallel, performs anti-islanding simulation on the parallel models, and determines whether the anti-islanding performance of the photovoltaic system is qualified based on the anti-islanding simulation results of the parallel models. The present invention detects the anti-islanding performance of the photovoltaic system as a whole based on the simulation models corresponding to the photovoltaic inverters, thereby solving the problem in the prior art that the anti-islanding performance of the photovoltaic system as a whole cannot be detected due to the limited capacity of the test device. At the same time, it avoids the problem that the sampling results of a single machine cannot represent the detection results of multiple machines.

[0109] Among them, before the simulation models corresponding to the photovoltaic inverters are connected in parallel, the simulation models corresponding to the photovoltaic inverters are simulated first, and then the simulation models are verified based on the simulation results. Finally, the parameters of the models that fail the verification are adjusted to improve the accuracy of the models.

[0110] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0111] 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. 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.

[0112] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work 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 The function specified in one or more boxes.

[0113] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for detecting anti-islanding performance of a photovoltaic system, characterized in that: The method comprises: The simulation models corresponding to each photovoltaic inverter are connected in parallel, and anti-islanding simulation is performed on the parallel models; Determine whether the anti-islanding performance of the photovoltaic system is qualified based on the anti-islanding simulation results of the parallel model; Before connecting the simulation models corresponding to the photovoltaic inverters in parallel, the method includes: Perform anti-islanding simulation on the simulation model corresponding to each photovoltaic inverter; Performing model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter to obtain a model verification result; Adjust the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified until the model verification is qualified; The performing model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter to obtain the model verification result includes: The root mean square error F between the simulated data and the measured data of the grid connection point in the anti-islanding simulation results of the i-th photovoltaic inverter is calculated as follows: i，Err : Where, F i，f_start is the grid connection point simulation data corresponding to the simulation start time in the anti-islanding simulation result of the i-th photovoltaic inverter, F i，f_end is the grid connection point simulation data corresponding to the end of the simulation in the anti-islanding simulation result of the i-th photovoltaic inverter, F i，s_start is the measured data of the grid connection point corresponding to the starting time of the simulation of the i-th photovoltaic inverter, F i，s_end is the measured data of the grid connection point corresponding to the end of the simulation of the i-th photovoltaic inverter; If F i，err If the value is less than the preset value, the verification result of the simulation model corresponding to the i-th photovoltaic inverter is qualified, otherwise it is unqualified; Where, i∈[1, N], N is the total number of PV inverters; The determining whether the anti-islanding performance of the photovoltaic system is qualified according to the anti-islanding simulation results of the parallel-connected models includes: If the maximum value of the photovoltaic inverter tripping time in the anti-islanding simulation result of the parallel model is greater than the preset tripping time, the test result of the photovoltaic system anti-islanding performance is qualified, otherwise it is unqualified.

2. The method according to claim 1, wherein The positive feedback coefficients of the simulation models corresponding to the photovoltaic inverters whose verification results of the adjustment model are unqualified include: Obtain the curvature k of the grid connection point simulation data curve of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified f The curvature k of the measured data curve of the grid connection point of each photovoltaic inverter whose model verification result is unqualified s ; If k f ≥k s , the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is reduced according to the preset step size; otherwise, the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is increased according to the preset step size.

3. A photovoltaic system anti-islanding performance detection device, characterized in that: The device comprises: The simulation unit is used to connect the simulation models corresponding to the photovoltaic inverters in parallel and perform anti-islanding simulation on the parallel models; A detection unit is used to determine whether the anti-islanding performance of the photovoltaic system is qualified based on the anti-islanding simulation results of the parallel-connected model; The device further comprises: The simulation subunit is used to perform anti-islanding simulation on the simulation model corresponding to each photovoltaic inverter; a verification unit, configured to perform model verification on the simulation model corresponding to each photovoltaic inverter based on the grid connection point simulation data in the anti-islanding simulation result of each photovoltaic inverter, and obtain a model verification result; An adjustment unit, used for adjusting the positive feedback coefficient of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified, until the model verification is qualified; The verification unit is specifically used to: The root mean square error F between the simulated data and the measured data of the grid connection point in the anti-islanding simulation results of the i-th photovoltaic inverter is calculated as follows: i，err : Where, F i，f_start is the grid connection point simulation data corresponding to the simulation start time in the anti-islanding simulation result of the i-th photovoltaic inverter, F i，f_end is the grid connection point simulation data corresponding to the end of the simulation in the anti-islanding simulation result of the i-th photovoltaic inverter, F i，s_start is the measured data of the grid connection point corresponding to the starting time of the simulation of the i-th photovoltaic inverter, F i，s_end is the measured data of the grid connection point corresponding to the end of the simulation of the i-th photovoltaic inverter; If F i,err If the value is less than the preset value, the verification result of the simulation model corresponding to the i-th photovoltaic inverter is qualified, otherwise it is unqualified; Where, i∈[1,N], N is the total number of PV inverters; The detection unit is specifically used for: If the maximum value of the photovoltaic inverter tripping time in the anti-islanding simulation result of the parallel model is greater than the preset tripping time, the test result of the photovoltaic system anti-islanding performance is qualified, otherwise it is unqualified.

4. The device according to claim 3, characterized in that The adjustment unit is specifically used to: Obtain the curvature k of the grid connection point simulation data curve of the simulation model corresponding to each photovoltaic inverter whose model verification result is unqualified f The curvature k of the measured data curve of the grid connection point of each photovoltaic inverter whose model verification result is unqualified s ; If k f ≥k s , the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is reduced according to the preset step size; otherwise, the positive feedback coefficient of the simulation model corresponding to the photovoltaic inverter whose model verification result is unqualified is increased according to the preset step size.

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