A method and system for evaluating reactive power support capability of a grid-connected wind turbine generator

Abstract

The application provides a network-constructed wind turbine reactive power support capability evaluation method and system, and relates to the technical field of power systems.The method comprises the following steps: obtaining active power output by a to-be-tested unit before disturbance; adding disturbance, adjusting the terminal voltage amplitude of the to-be-tested unit, and restoring after a set time; obtaining the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance; drawing a positive sequence reactive current variation requirement curve; and judging whether the steady-state reactive current-voltage characteristic of the to-be-tested unit meets the requirement according to the positional relationship between the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance and the drawn positive sequence reactive current variation requirement curve.The application can realize accurate evaluation of the reactive power support capability of a network-constructed wind turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method and system for evaluating the reactive support capability of a grid-connected wind turbine generator set. Background Art

[0002] With the construction of new power systems dominated by renewable energy, the penetration of renewable energy generation, represented by wind power and photovoltaics, continues to increase. To address the weak active support capabilities associated with grid-following control systems for renewable energy generation, various grid-forming (GFM) converter control strategies have been proposed in recent years. GFM converters can mimic the operating characteristics of synchronous generators, autonomously construct voltages, and proactively support the grid.

[0003] Grid-connected wind power, a key development direction in wind power technology, is crucial for the stability and security of new power systems due to its dynamic reactive power support and fault ride-through capabilities. Research on grid-connected wind turbines has largely focused on their control strategies and theoretical modeling. However, there is a lack of research on evaluation indicators and testing methods for their dynamic reactive power support capabilities. Furthermore, there is a lack of unified standards for testing and evaluating dynamic reactive current support capabilities.

[0004] Compared with grid-following wind turbines, the evaluation of the dynamic reactive current support capability of grid-connected wind turbines has the following difficulties and challenges:

[0005] (1) Complexity of the control mechanism: Grid-following wind turbines adjust their reactive power output by phase-locking the grid voltage signal. Their dynamic reactive current support capability test primarily assesses the wind turbine's passive response capability. Grid-connected wind turbines, on the other hand, do not rely on external grid signals but instead actively generate voltage and frequency, providing dynamic grid support capabilities similar to synchronous generators. This requires simulating complex grid interactions and involves a variety of complex control algorithms (such as virtual synchronous machines and droop control). The stability of the control strategy under different grid disturbance conditions must be verified.

[0006] (2) Difficulty in testing dynamic characteristics: The dynamic reactive response test of grid-following wind turbines mainly focuses on basic indicators such as response time and steady-state error. However, the dynamic reactive response of grid-connecting wind turbines also needs to evaluate their support capacity, stability and fault recovery characteristics for the power grid, requiring a multi-dimensional performance indicator assessment. Summary of the Invention

[0007] In order to address at least one deficiency of the prior art, an object of the present invention is to provide a method and system for evaluating the reactive support capability of a grid-type wind turbine generator set, so as to achieve accurate evaluation of the reactive support capability of the grid-type wind turbine generator set.

[0008] In order to achieve the above-mentioned purpose, according to some embodiments, a first aspect of the present application provides a method for evaluating reactive power support capability of a grid-connected wind turbine, comprising:

[0009] acquiring active power output of the to-be-tested unit before disturbance;

[0010] adding disturbance, adjusting the terminal voltage amplitude of the to-be-tested unit, and restoring after a set time;

[0011] acquiring the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance;

[0012] drawing a positive sequence reactive current variation requirement curve, and judging whether the steady-state reactive current-voltage characteristic of the to-be-tested unit meets the requirement according to the position relationship between the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance and the drawn positive sequence reactive current variation requirement curve.

[0013] In a further technical solution, if the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance meets the following formula, it is judged that the steady-state reactive current-voltage characteristic of the to-be-tested unit meets the requirement:

[0014]

[0015] wherein, the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance, K1 is the upper limit of strong excitation reactive current coefficient, K2 is the upper limit of strong excitation reactive current coefficient, β is the active power correction coefficient, P0 represents the steady-state active power output value of the to-be-tested unit before disturbance, U represents the terminal voltage amplitude of the to-be-tested unit, and U ch represents the upper limit of strong excitation voltage.

[0016] In a further technical solution, the method further comprises a reactive current dynamic response speed evaluation method, which comprises: changing the terminal voltage amplitude of the to-be-tested unit, recording the waveform information of the reactive current with time, calculating the response time, and judging whether the reactive current dynamic response speed meets the requirement according to the response time.

[0017] In a further technical solution, the method further comprises a low voltage ride through evaluation method, which comprises: reducing the terminal voltage of the to-be-tested unit, and evaluating the low voltage ride through capability of the to-be-tested unit according to whether the to-be-tested unit remains continuous operation without being off-grid in the voltage drop interval.

[0018] In a further technical solution, the method further comprises a high voltage ride through evaluation method, which comprises: increasing the terminal voltage of the to-be-tested unit, and evaluating the high voltage ride through capability of the to-be-tested unit according to whether the to-be-tested unit remains continuous operation without being off-grid in the voltage rise interval.

[0019] A further technical solution also includes an active power impact evaluation method, which comprises: lowering the terminal voltage of the unit under test to simulate a grid fault, setting a time for the rear-end voltage to recover, and evaluating the reactive power support capacity of the unit under test under active power impact based on the difference between the maximum value and the steady-state value of the active power of the unit under test.

[0020] A second aspect of the present invention provides a reactive support capability evaluation system for a grid-connected wind turbine generator system, comprising:

[0021] An active power acquisition module is configured to acquire the active power output by the unit under test before the disturbance;

[0022] The disturbance module is configured to add disturbances, adjust the terminal voltage amplitude of the unit under test, and recover after a set time;

[0023] A steady-state reactive current amplitude change acquisition module is configured to acquire the steady-state reactive current amplitude change and the corresponding terminal voltage value of the unit under test after the disturbance;

[0024] The judgment module is configured to draw a positive-sequence reactive current change requirement curve, and judge whether the steady-state reactive current-voltage characteristics of the unit under test meet the requirements based on the positional relationship between the steady-state reactive current amplitude change of the unit under test and the corresponding terminal voltage value after the disturbance and the drawn positive-sequence reactive current change requirement curve.

[0025] A third aspect of the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to complete the steps of the above-mentioned method for evaluating the reactive support capacity of a grid-type wind turbine.

[0026] A fourth aspect of the present invention provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the steps of the above-mentioned method for evaluating the reactive support capacity of a grid-connected wind turbine.

[0027] A fifth aspect of the present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of the above-mentioned method for evaluating the reactive support capability of a grid-connected wind turbine.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The application provides a network-constructed wind turbine reactive power support capability evaluation method and system, and aims at the problem that the prior art lacks reactive power support capability evaluation indexes and test methods of network-constructed wind turbines.

[0030] Advantages of the additional aspects of the application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings, which form a part of the specification, are included to provide a further understanding of the application and are incorporated herein by reference. The illustrations are shown for the purpose of enabling those skilled in the art to implement the application and are not intended to limit the scope of the application.

[0032] Figure 1 The structural schematic diagram of the test system in the embodiment one of the application is shown in the figure;

[0033] Figure 2 The schematic diagram of the positive sequence reactive current change requirement curve in the embodiment one of the application is shown in the figure;

[0034] Figure 3 The schematic diagram of the reactive current-time characteristic curve in the embodiment one of the application is shown in the figure;

[0035] Figure 4 The schematic diagram of the low voltage ride through curve in the embodiment one of the application is shown in the figure;

[0036] Figure 5 The schematic diagram of the high voltage ride through curve in the embodiment one of the application is shown in the figure;

[0037] Figure 6 The schematic diagram of the active power-time characteristic curve in the embodiment one of the application is shown in the figure;

[0038] Figure 7 The schematic diagram of the end voltage change curve in the first test of the embodiment two of the application is shown in the figure;

[0039] Figure 8 The comparative schematic diagram of the reactive current-voltage characteristic curve and the requirement curve in the first test of the embodiment two of the application is shown in the figure;

[0040] Figure 9 The schematic diagram of the reactive current dynamic response curve in the first test of the embodiment two of the application is shown in the figure;

[0041] Figure 10 Schematic diagram of the terminal voltage change curve of the second test in the second embodiment of the present invention;

[0042] Figure 11 Schematic diagram comparing the reactive current-voltage characteristic curve and the required curve in the second test in Example 2 of the present invention;

[0043] Figure 12 Schematic diagram of a reactive current dynamic response curve of the second test in the second embodiment of the present invention;

[0044] Figure 13 Schematic diagram comparing active power curves that meet the requirements and those that do not meet the requirements in the second embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Example 1

[0047] Embodiment 1 of the present invention, as Figures 1-6 As shown, a method for evaluating the reactive support capability of a grid-connected wind turbine is provided, including:

[0048] Obtain the active power output of the unit under test before the disturbance;

[0049] Add disturbance, adjust the terminal voltage amplitude of the unit under test, and recover after a set time;

[0050] Obtain the change in the steady-state reactive current amplitude of the unit under test after the disturbance;

[0051] Draw the positive sequence reactive current change requirement curve, and judge whether the steady state reactive current-voltage characteristics of the unit under test meet the requirements based on the positional relationship between the steady state reactive current amplitude change of the unit under test after the disturbance and the drawn positive sequence reactive current change requirement curve.

[0052] To address the existing lack of evaluation indicators and testing methods for the reactive power support capability of grid-type wind turbines, this embodiment connects a grid-type wind turbine to specific testing equipment to construct a test system. By varying the terminal voltage amplitude of the unit under test and generating asymmetric positive and negative sequence voltages in the testing equipment, the three-phase terminal voltage and current of the grid-type wind turbine are measured and recorded, and the reactive current component and output active power are calculated. This first generates an evaluation indicator for the reactive current support capability, including an evaluation indicator for the reactive current-voltage characteristic and fault ride-through. Secondly, the reactive current-voltage characteristic and fault voltage characteristic curves are obtained and compared with the evaluation indicators for verification.

[0053] like Figure 1As shown, the grid-type wind turbine to be tested is connected to a specific test device. Figure 1 Medium X eq represents the equivalent reactance of the converter, X s Represents line reactance. The connected test equipment is a large-capacity, four-quadrant, programmable, fast-response three-phase AC power supply. By adjusting the test equipment's output voltage, changing the voltage amplitude at the tested unit's terminals, and causing voltage drops in the test equipment, the three-phase terminal voltage and current of the grid-connected wind turbine are measured and recorded, and the reactive current component and output active power are calculated.

[0054] The evaluation of reactive current-voltage characteristics includes steady-state evaluation and dynamic evaluation. Steady-state evaluation uses the steady-state reactive current amplitude change Specifically, the evaluation method is as follows:

[0055] (1) Record the active power output P0 of the unit under test before the disturbance;

[0056] (2) Adjust the output voltage of the test equipment to change the voltage amplitude U at the terminal of the unit to be tested, and then restore it after a period of time;

[0057] (3) Record the change in the steady-state reactive current amplitude of the unit under test after the disturbance ;

[0058] (4) Obtain several sets of pre-disturbance output active power-terminal voltage-steady-state reactive current amplitude data.

[0059] Change in the amplitude of the steady-state reactive current output by the measured unit after the disturbance The following requirements must be met:

[0060]

[0061] Among them, K1 is the reactive current coefficient before the upper limit of strong excitation, indicating that the reactive current will increase or decrease rapidly when the voltage changes; K2 is the reactive current coefficient after the upper limit of strong excitation. For the safety of the unit, the change of reactive current will be significantly reduced after the strong excitation reaches the upper limit; β is the active power correction coefficient. The smaller the active power, the greater the change of reactive current with voltage. It is an active power correction factor, considering the differences in reactive current characteristics under different active power output conditions under the same voltage disturbance; P0 represents the steady-state active power output value of the unit under test before the disturbance; U represents the terminal voltage amplitude of the unit under test; U ch Indicates the upper limit voltage of the forced excitation, the voltage drops to U ch Later it was considered that the upper limit of the incentive had been reached.

[0062] Typical values ​​of the parameters are: K1=2, K2=1, β=0.3, U ch =0.7.

[0063] The piecewise function curve of the above formula is the positive sequence reactive current change requirement curve, such as Figure 2 As shown in the figure, the reactive current-voltage characteristics required for this are explained in detail:

[0064] For grid-connected units, the phase angle difference with the external system voltage varies at different active power outputs. Therefore, when the voltage amplitude changes, the reactive current characteristics are affected to a certain extent. Therefore, a correction based on P0 is incorporated into the required reactive current-voltage characteristics. The smaller P0, the greater the change in reactive current with voltage.

[0065] When the terminal voltage of a grid-type unit drops, it will generally perform "strong excitation" to increase the internal potential amplitude and further increase the output reactive current. However, for the safety of the unit, there is an upper limit to strong excitation. When the upper limit is reached, the voltage drops further and the increase in reactive current will be significantly reduced. Therefore, a segmented characteristic is added to the required reactive current-voltage characteristic. When the voltage drops to U ch Later it was considered that the upper limit of the incentive had been reached.

[0066] In addition to the static requirement of reactive current-voltage characteristics, there are also requirements for the dynamic response speed of reactive current.

[0067] Grid-type generators exhibit voltage source characteristics and should be able to spontaneously change their reactive current output in response to voltage amplitude changes, demonstrating rapid reactive current response. In the previous test, after varying the terminal voltage amplitude of the generator under test, not only was the steady-state reactive current amplitude recorded, but also the reactive current-time waveform was recorded to measure the reactive current response speed.

[0068] like Figure 3 As shown in Figure 1, the response time, that is, the time required for the reactive current to reach 90% of the steady-state reactive current amplitude after the disturbance occurs, shall not exceed 20ms, which is the requirement for the dynamic response speed of the reactive current.

[0069] In addition to the requirements for reactive current-voltage characteristics and the dynamic response speed of reactive current, grid-connected wind turbines should also meet the requirements for low-voltage and high-voltage ride-through of the wind turbines in the event of a grid fault, as well as the requirements for active power surge after the fault is cleared.

[0070] Wind turbine low voltage and high voltage ride through requirements. Figure 4 The voltage drop range shown (three-phase voltage drop) and Figure 5Within the voltage increase range shown, the wind turbine should remain connected to the grid and operate continuously. Connect the grid-connected wind turbine to the test device. This test device is a large-capacity, programmable, fast-response, four-quadrant, three-phase inverter capable of rapidly changing output voltage. This changes the terminal voltage of the unit under test, i.e., by changing the modulation signal of the test device at time 0, thereby changing its output voltage. After the voltage drops or rises for a period of time, it recovers. In this case, the wind turbine should not be disconnected from the grid and should assume the responsibility of voltage support.

[0071] Requirements and testing methods for active power surge after fault clearance. After a grid fault causes a voltage drop, the imbalance between input mechanical power and output active power in synchronous generators can lead to increased unit speed and a power angle swing. After the fault is cleared and the voltage is restored, a significant active power surge can occur.

[0072] For grid-type wind turbines, the rotor motion equations governing their internal potential rotation are fictitious. Post-fault motion characteristics can be easily controlled to avoid transient stability issues associated with power angle swings in synchronous machines. This capability is essential for grid-type wind turbines and can be reflected in the magnitude of the active power surge after a fault is cleared.

[0073] During the voltage drop test, the output active power-time waveform information is recorded simultaneously, and the curve is as follows: Figure 6 Requirement: After voltage recovery, the difference between the maximum active power and the recovered steady-state value (i.e., active power surge) shall not exceed 20% of the steady-state value.

[0074] Example 2

[0075] This embodiment provides a reactive power support capability evaluation system for a grid-connected wind turbine generator system, including:

[0076] An active power acquisition module is configured to acquire the active power output by the unit under test before the disturbance;

[0077] The disturbance module is configured to add disturbances, adjust the terminal voltage amplitude of the unit under test, and recover after a set time;

[0078] A steady-state reactive current amplitude change acquisition module is configured to acquire the steady-state reactive current amplitude change and the corresponding terminal voltage value of the unit under test after the disturbance;

[0079] The judgment module is configured to draw a positive-sequence reactive current change requirement curve, and judge whether the steady-state reactive current-voltage characteristics of the unit under test meet the requirements based on the positional relationship between the steady-state reactive current amplitude change of the unit under test and the corresponding terminal voltage value after the disturbance and the drawn positive-sequence reactive current change requirement curve.

[0080] It should be noted here that the various modules in this embodiment correspond one-to-one to the steps of the method in Example 1, and the specific implementation process is the same, which will not be repeated here.

[0081] Example 3

[0082] This embodiment uses simulation software to build a test system model, and performs simulation testing using the method in the first embodiment to demonstrate the method in the first embodiment.

[0083] (1) Test of reactive current-voltage characteristics

[0084] The test was performed according to the method and requirements in Example 1.

[0085] Adjust the output voltage of the test equipment and change the voltage amplitude of the unit under test to U=0.7625 (for the convenience of expression, the digital values ​​in this embodiment are all per unit values, the same below), and continue to run for a period of time and then recover. Figure 7 As shown. Record the change in the steady-state reactive current amplitude of the unit under test after the disturbance ΔI Q+ =3.225. The output active power before disturbance - terminal voltage - steady-state reactive current amplitude data are obtained, where the output active power before disturbance P0 = 0.9, and the proposed area that meets the requirements ( Figure 2 ) for comparison, such as Figure 8 As shown in the figure, it can be seen that the steady-state reactive current amplitude-voltage characteristics are within the required area.

[0086] In addition to the static requirement of reactive current-voltage characteristics, the dynamic response speed of reactive current is also tested, such as Figure 9 As shown in the figure, it can be seen that the time required for the reactive current to reach 90% of the steady-state reactive current amplitude after the disturbance occurs does not exceed 20ms, which meets the requirements of the dynamic response speed of the reactive current.

[0087] Then adjust the output voltage of the test equipment and change the voltage amplitude of the unit under test to U=0.6625. Continue to run for a period of time to recover. Figure 10 As shown. Record the change in the steady-state reactive current amplitude of the unit under test after the disturbance ΔI Q+ =3.195. The output active power before disturbance - terminal voltage - steady-state reactive current amplitude data are obtained, where the output active power before disturbance P0 = 0.9, and compared with the proposed area that meets the requirements, such as Figure 11 As shown in the figure, it can be seen that the steady-state reactive current amplitude-voltage characteristics are within the required area.

[0088] Then the dynamic response speed of reactive current is also tested, such as Figure 12As shown in the figure, it can be seen that the time required for the reactive current to reach 90% of the steady-state reactive current amplitude after the disturbance occurs does not exceed 20ms, which meets the requirements of the dynamic response speed of the reactive current.

[0089] (2) Test of active power impact after fault clearing

[0090] Adjust the output voltage of the test equipment. The grid fault causes the voltage to drop at 1s, and the fault is cleared at 1.5s. The steady-state value of active power before and after the fault is P0=0.9. Simulate the test unit that meets the reactive current support capacity requirements and the unit with poor reactive support capacity. The results are compared. Figure 13 As shown in the figure, after voltage recovery, as shown by the red curve, the difference between the maximum active power and the steady-state value after recovery for the units under test that meet the reactive current support capability requirements does not exceed 20% of the steady-state value, meeting the requirements. However, for units with poor reactive support capability, as shown by the blue curve, the active power surge reaches 200% of the steady-state value, which does not meet the requirements.

[0091] Example 4

[0092] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to complete the steps of the method in the first embodiment.

[0093] The processor may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor may be implemented in at least one of the following hardware forms: a DSP (Digital Signal Processing), an FPGA (Field-Programmable Gate Array), or an LA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor is used to process data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor may integrate a graphics processing unit (GPU), which is responsible for rendering and drawing content required for display screens. In some embodiments, the processor may also include an artificial intelligence (AI) processor, which is used to handle computational operations related to machine learning.

[0094] The memory may include one or more computer-readable media, which may be non-transitory. The memory may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable medium in the memory is used to store at least one computer program, which is executed by the processor to implement a method for evaluating the reactive support capability of a grid-connected wind turbine provided in an embodiment of the present disclosure.

[0095] Those skilled in the art will appreciate that the electronic device provided in this embodiment may include more or fewer components, or combine certain components, or adopt different component arrangements.

[0096] Example 5

[0097] This embodiment provides a computer-readable storage medium for storing computer instructions. When the computer instructions are executed by a processor, the steps of the method in the first embodiment are completed.

[0098] Example 6

[0099] This embodiment provides a computer program product, including a computer program / instruction, which implements the steps of the method in embodiment 1 when executed by a processor.

[0100] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for evaluating the reactive support capability of a grid-connected wind turbine generator system, characterized in that: include: Obtain the active power output of the unit under test before the disturbance; Add disturbance, adjust the terminal voltage amplitude of the unit under test, and recover after a set time; Obtain the change in the steady-state reactive current amplitude of the unit under test after the disturbance; Draw a positive sequence reactive current change requirement curve, and judge whether the steady state reactive current-voltage characteristics of the unit under test meet the requirements based on the positional relationship between the steady state reactive current amplitude change of the unit under test after the disturbance and the drawn positive sequence reactive current change requirement curve; If the change in the steady-state reactive current amplitude of the unit under test after the disturbance satisfies the following formula, it is judged that the steady-state reactive current-voltage characteristics of the unit under test meet the requirements: in, It represents the change in the steady-state reactive current amplitude of the unit under test after the disturbance, K1 is the reactive current coefficient before the upper limit of the strong excitation, K2 is the reactive current coefficient after the upper limit of the strong excitation, β is the active power correction coefficient, P0 represents the steady-state active power output value of the unit under test before the disturbance, U represents the terminal voltage amplitude of the unit under test, U ch Indicates the upper limit voltage of forced excitation.

2. A method for evaluating reactive support capability of a grid-connected wind turbine generator system according to claim 1, characterized in that: It also includes a method for evaluating the dynamic response speed of reactive current, including: changing the terminal voltage amplitude of the unit to be tested, recording the waveform information of the reactive current over time, calculating the response time, and judging whether the dynamic response speed of the reactive current meets the requirements based on the response time.

3. The method for evaluating reactive support capability of a grid-connected wind turbine generator system according to claim 1, wherein: It also includes a low voltage ride-through evaluation method, comprising: reducing the terminal voltage of the unit under test, and evaluating the low voltage ride-through capability of the unit under test based on whether the unit under test maintains continuous operation without being disconnected from the grid within the voltage drop range.

4. The method for evaluating reactive support capability of a grid-connected wind turbine generator system according to claim 1, wherein: It also includes a high voltage ride-through evaluation method, comprising: increasing the terminal voltage of the unit under test, and evaluating the high voltage ride-through capability of the unit under test based on whether the unit under test maintains continuous operation without being disconnected from the grid within the voltage increase range.

5. The method for evaluating reactive support capability of a grid-connected wind turbine generator system according to claim 1, wherein: It also includes an active power impact evaluation method, including: reducing the terminal voltage of the unit to be tested to simulate a power grid failure, setting a time for the rear end voltage to recover, and evaluating the reactive power support capacity of the unit to be tested under active power impact based on the difference between the maximum value and the steady-state value of the active power of the unit to be tested.

6. A reactive support capability evaluation system for grid-connected wind turbines, characterized in that: include: An active power acquisition module is configured to acquire the active power output by the unit under test before the disturbance; The disturbance module is configured to add disturbances, adjust the terminal voltage amplitude of the unit under test, and recover after a set time; A steady-state reactive current amplitude change acquisition module is configured to acquire the steady-state reactive current amplitude change and the corresponding terminal voltage value of the unit under test after the disturbance; a judgment module configured to draw a positive-sequence reactive current change requirement curve, and judge whether the steady-state reactive current-voltage characteristic of the unit under test meets the requirements based on the positional relationship between the steady-state reactive current amplitude change of the unit under test and the corresponding terminal voltage value after the disturbance and the drawn positive-sequence reactive current change requirement curve; If the change in the steady-state reactive current amplitude of the unit under test after the disturbance satisfies the following formula, it is judged that the steady-state reactive current-voltage characteristics of the unit under test meet the requirements: in, It represents the change in the steady-state reactive current amplitude of the unit under test after the disturbance, K1 is the reactive current coefficient before the upper limit of the strong excitation, K2 is the reactive current coefficient after the upper limit of the strong excitation, β is the active power correction coefficient, P0 represents the steady-state active power output value of the unit under test before the disturbance, U represents the terminal voltage amplitude of the unit under test, U ch Indicates the upper limit voltage of forced excitation.

7. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to complete the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that Used to store computer instructions, which, when executed by a processor, complete the steps of the method according to any one of claims 1 to 5.

9. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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