Method and system for evaluating reactive power supporting capability of network construction type wind turbine generator

Abstract

The invention provides a method and a system for evaluating reactive power supporting capability of a network-forming type wind turbine generator, and relates to the technical field of power systems, and the method comprises the steps: obtaining active power outputted by a to-be-tested generator before disturbance; adding disturbance, adjusting the terminal voltage amplitude of the to-be-tested unit, and recovering after setting time; obtaining the steady-state reactive current amplitude variation of the to-be-tested unit after disturbance; and drawing a positive-sequence reactive current variable quantity requirement curve, and judging whether the steady-state reactive current-voltage characteristics of the to-be-tested unit meet requirements or not according to the position relation between the steady-state reactive current amplitude variable quantity of the to-be-tested unit after disturbance and the drawn positive-sequence reactive current variable quantity requirement curve. According to the method, the reactive power supporting capability of the network-forming type wind turbine generator can be accurately evaluated.

Description

Technical Field

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

[0002] With the construction of new power systems dominated by new energy, the penetration rate of new energy power generation represented by wind power and photovoltaic power generation continues to increase. In the face of the problems such as weak active support capability brought about by the grid-following control of new energy power generation systems, in recent years, a variety of grid-forming (GFM) converter control strategies have been proposed. Grid-forming converters can simulate the operating characteristics of synchronous generators, independently build voltage, and have the ability to actively support the power grid.

[0003] As an important development direction of wind power technology, grid-connected wind power has a dynamic reactive power support capability and fault ride-through capability that are of great significance to the stability and safety of new power systems. In related technologies, most of the research on grid-connected wind turbines focuses on the control strategy and theoretical modeling of grid-connected wind turbines. There is a lack of research on the evaluation indicators and test methods for the dynamic reactive power support capability of grid-connected wind turbines, and there is also a lack of unified standards for the test and evaluation of dynamic reactive current support capability.

[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: (1) Complexity of control mechanism: Grid-following wind turbines adjust the reactive output of wind turbines by phase locking with grid voltage signals. The dynamic reactive current support capability test mainly evaluates the passive response capability of wind turbines. Grid-connecting wind turbines do not rely on external grid signals, but actively generate voltage and frequency to provide 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, droop control, etc.). It is necessary to verify the stability of the control strategy under different grid disturbance conditions.

[0005] (2) Difficulty in testing dynamic characteristics: The dynamic reactive power response test of grid-following wind turbines mainly focuses on basic indicators such as response time and steady-state error. The dynamic reactive power response of grid-connecting wind turbines also needs to evaluate their support capacity, stability and fault recovery characteristics for the power grid, and requires the evaluation of multi-dimensional performance indicators. Summary of the invention

[0006] In order to solve 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 a grid-type wind turbine generator set.

[0007] In order to achieve the above object, according to some embodiments, a first aspect of the present invention provides a method for evaluating reactive support capability of a grid-connected wind turbine generator system, comprising: Obtain the active power output of the unit under test before the disturbance; Add disturbance, adjust the terminal voltage amplitude of the unit to be tested, and recover after a set time; Obtain the change in the steady-state reactive current amplitude of the unit to be tested after the disturbance; 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.

[0008] A further technical solution is that 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 characteristic of the unit under test meets the requirements:

[0009] in, It indicates the change of steady-state reactive current amplitude of the unit under test after the disturbance, K1 is the reactive current coefficient before the upper limit of strong excitation, K2 is the reactive current coefficient after the upper limit of strong excitation, β is the active power correction coefficient, P0 indicates the steady-state output value of active power of the unit under test before the disturbance, U indicates the terminal voltage amplitude of the unit under test, U ch Indicates the upper limit voltage of forced excitation.

[0010] A further technical solution also includes a method for evaluating the dynamic response speed of reactive current, comprising: 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.

[0011] A further technical solution also includes a low voltage ride-through evaluation method, comprising: lowering 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.

[0012] A further technical solution 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.

[0013] A further technical solution also includes an active power impact evaluation method, comprising: reducing the terminal voltage of the unit under test 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 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.

[0014] A second aspect of the present invention provides a reactive power support capability evaluation system for a grid-connected wind turbine generator set, comprising: An active power acquisition module is configured to acquire the active power output by the unit to be tested 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 to be tested after the disturbance; 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 position 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.

[0015] 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-connected wind turbine.

[0016] 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.

[0017] A fifth aspect of the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the above-mentioned method for evaluating the reactive support capacity of a grid-connected wind turbine.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method and system for evaluating the reactive support capacity of a grid-type wind turbine. In view of the problem that the prior art lacks evaluation indicators and test methods for the dynamic reactive support capacity of a grid-type wind turbine, the grid-type wind turbine to be tested is connected to the test equipment, and the reactive support capacity of the grid-type wind turbine is evaluated by changing the terminal voltage of the unit to be tested, and the change in the amplitude of the steady-state reactive current after the disturbance is recorded to determine whether the steady-state reactive current-voltage characteristics of the unit to be tested meet the requirements. In addition, the present invention also realizes a multi-dimensional rapid and accurate evaluation of the reactive support capacity of the grid-type wind turbine by evaluating the dynamic response speed of reactive current, high and low voltage ride-through, and active power impact.

[0019] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 This is a schematic diagram of the structure of the test system in Embodiment 1 of the present invention; Figure 2 Schematic diagram of a positive sequence reactive current change requirement curve in Embodiment 1 of the present invention; Figure 3 Schematic diagram of a reactive current-time characteristic curve in Embodiment 1 of the present invention; Figure 4 is a schematic diagram of a low voltage ride through curve in Embodiment 1 of the present invention; Figure 5 is a schematic diagram of a high voltage ride through curve in the first embodiment of the present invention; Figure 6 Schematic diagram of active power-time characteristic curve in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of a terminal voltage variation curve of the first test in the second embodiment of the present invention; Figure 8 Schematic diagram of comparison between the reactive current-voltage characteristic curve and the required curve in the first test in the second embodiment of the present invention; Fig. 9 It is a schematic diagram of a reactive current dynamic response curve of the first test in the second embodiment of the present invention; Fig.10 is a schematic diagram of a terminal voltage variation curve of the second test in the second embodiment of the present invention; Fig.11 Schematic diagram of comparison between the reactive current-voltage characteristic curve and the required curve in the second test in the second embodiment of the present invention; Fig.12 A schematic diagram of a reactive current dynamic response curve of the second test in the second embodiment of the present invention; Fig.13 The figure is a schematic diagram for 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

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Embodiment 1 Embodiment 1 of the present invention, as Figure 1-Figure 6 As shown, a method for evaluating the reactive support capacity of a grid-connected wind turbine is provided, comprising: Obtain the active power output of the unit under test before the disturbance; Add disturbance, adjust the terminal voltage amplitude of the unit to be tested, and recover after a set time; Obtain the change in the steady-state reactive current amplitude of the unit to be tested after the disturbance; 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.

[0024] In view of the problem that the prior art lacks evaluation indicators and test methods for evaluating the reactive support capacity of grid-type wind turbines, this embodiment connects the grid-type wind turbines to specific test equipment, builds a test system, measures and records the three-phase terminal voltage and current of the grid-type wind turbines by changing the terminal voltage amplitude of the unit to be tested, and makes the test equipment generate positive and negative sequence asymmetric voltage, calculates the reactive current component and the output active power. Thus, the reactive current support capacity evaluation index is first obtained, including the reactive current-voltage characteristic and the fault crossing evaluation index; secondly, the reactive current-voltage characteristic and the fault voltage characteristic curve are obtained, and compared with the evaluation index for verification.

[0025] like Figure 1 As shown in the figure, 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 Indicates line reactance. The connected test equipment is a large-capacity, four-quadrant, programmable, fast-response three-phase AC power supply. The output voltage of the test equipment is adjusted to change the voltage amplitude of the tested unit terminal, and the test equipment is caused to produce a voltage drop. The three-phase terminal voltage and current of the grid-type wind turbine are measured and recorded, and the reactive current component and the output active power are calculated.

[0026] The evaluation of reactive current-voltage characteristics includes steady-state evaluation and dynamic evaluation. The steady-state evaluation uses the steady-state reactive current amplitude change Specifically, the evaluation method is as follows: (1) Record the active power output P0 of the unit under test before the disturbance; (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; (3) Record the change in the steady-state reactive current amplitude of the unit under test after the disturbance ; (4) Obtain several sets of pre-disturbance output active power-terminal voltage-steady-state reactive current amplitude data.

[0027] The change in the amplitude of the steady-state reactive current output of the measured unit after the disturbance The following requirements must be met:

[0028] Among them, K1 is the reactive current coefficient before the upper limit of strong excitation, which means that when the voltage changes, the reactive current will increase or decrease rapidly; 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 a correction of active power. It is based on the consideration that the reactive current characteristics are different under different active power output conditions of the same voltage disturbance; P0 represents the steady-state output value of active power of the unit under test before the disturbance; U represents the voltage amplitude of the unit under test; U ch Indicates the upper limit voltage of strong excitation, the voltage drops to U ch Later it was considered that the upper limit of the incentive had been reached.

[0029] Typical values ​​of the parameters are: K1=2, K2=1, β=0.3, U ch =0.7.

[0030] The piecewise function curve of the above formula is the positive sequence reactive current change requirement curve, such as Figure 2 As shown, the reactive current-voltage characteristics required for this are explained in detail: For grid-type units, there are different phase angle differences with the external system voltage at different active power outputs. Therefore, when the voltage amplitude changes, the reactive current characteristics will be affected to a certain extent. Therefore, a correction based on P0 is added to the required reactive current-voltage characteristics. The smaller P0 is, the greater the change in reactive current with voltage.

[0031] 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 sake of unit safety, there is an upper limit to strong excitation. When the voltage drops further after reaching the upper limit, 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.

[0032] In addition to the static requirement of reactive current-voltage characteristics, there are also requirements for the dynamic response speed of reactive current.

[0033] The grid-type unit exhibits the characteristics of a voltage source. It should be able to spontaneously change the reactive current output after the voltage amplitude changes, and have a fast reactive current response capability. In the previous test, after changing the terminal voltage amplitude of the unit under test, in addition to recording the reactive current steady-state amplitude information, the reactive current-time waveform information is also recorded to measure the reactive current response speed.

[0034] like Figure 3 As shown in the figure, 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, and the dynamic response speed of the reactive current is required.

[0035] 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 wind turbines in the event of a grid fault, as well as the requirements for active power impact after the fault is cleared.

[0036] Wind turbine low voltage and high voltage ride through requirements. Figure 4 The voltage drop range shown (three-phase voltage drop) and Figure 5 In the voltage increase range shown, the wind turbine should remain connected to the grid and operate continuously. The grid-connected wind turbine to be tested is connected to a test device, which is a large-capacity, programmable, fast-response four-quadrant three-phase inverter power supply that can quickly change the output voltage. The terminal voltage of the unit to be tested is changed, that is, the modulation signal of the test device is changed 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.

[0037] Active power impact requirements and test methods after fault clearing. After a grid fault causes a voltage drop, for a synchronous machine, the imbalance between input mechanical power and output active power will cause the unit speed to increase and the power angle to swing. After the fault is cleared and the voltage is restored, there will be a large active power impact.

[0038] For grid-type wind turbines, the rotor motion equation that determines the internal potential rotation motion is fictitious, and the motion characteristics after a fault can be easily controlled to avoid transient stability problems such as the power angle swing of synchronous machines. This function is what grid-type units should have. It can be reflected by the size of the active power impact after the fault is cleared.

[0039] In the voltage drop test, the output active power-time waveform information is recorded at the same time, and the curve is as follows Figure 6 Requirement: After the voltage is restored, the difference between the maximum active power and the steady-state value after restoration (i.e. active power surge) shall not exceed 20% of the steady-state value.

[0040] Embodiment 2 This embodiment provides a reactive power support capability evaluation system for a grid-connected wind turbine generator set, including: An active power acquisition module is configured to acquire the active power output by the unit to be tested 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 to be tested after the disturbance; 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 position 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.

[0041] 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.

[0042] Embodiment 3 This embodiment uses simulation software to build a test system model, and performs simulation testing using the method in Embodiment 1 to test and demonstrate the method in Embodiment 1.

[0043] (1) Test of reactive current-voltage characteristics The test was performed according to the method and requirements in Example 1.

[0044] Adjust the output voltage of the test equipment, change the voltage amplitude of the unit under test to U=0.7625 (for the convenience of expression, the digital quantities in this embodiment are all per unit values, the same below), and continue to run for a period of time before recovery. 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, it can be seen from the figure that the steady-state reactive current amplitude-voltage characteristics are within the required area.

[0045] In addition to the static requirement of reactive current-voltage characteristics, the dynamic response speed of reactive current is also tested, such as Fig. 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.

[0046] Then adjust the output voltage of the test equipment, change the voltage amplitude of the unit under test to U=0.6625, and continue to run for a period of time to recover. Fig.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 Fig.11 As shown, it can be seen from the figure that the steady-state reactive current amplitude-voltage characteristics are within the required area.

[0047] The dynamic response speed of reactive current is also tested. Fig.12 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.

[0048] (2) Test of active power impact after fault clearing 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 units that meet the reactive current support capacity requirements and the units with poor reactive support capacity. The results are compared. Fig.13 As shown in the figure, after the voltage is restored, as shown by the red curve, the difference between the maximum active power of the tested unit that meets the reactive current support capacity requirements and the steady-state value after recovery does not exceed 20% of the steady-state value, which meets the requirements; while the unit with poor reactive support capacity, as shown by the blue curve, has an active power impact of 200% of the steady-state value, which does not meet the requirements.

[0049] Embodiment 4 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.

[0050] The processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and LA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor may also include an AI (Artificial Intelligence) processor, which is used to process computing operations related to machine learning.

[0051] 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, 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 used to be executed by the processor to implement a method for evaluating the reactive support capacity of a grid-type wind turbine provided in an embodiment of the present disclosure.

[0052] Those skilled in the art can understand that the electronic device provided in this embodiment can include more or fewer components, or combine certain components, or adopt different component arrangements.

[0053] Embodiment 5 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.

[0054] Embodiment 6 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.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for evaluating the reactive support capacity 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 to be tested, and recover after a set time; Obtain the change in the steady-state reactive current amplitude of the unit to be tested after the disturbance; 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.

2. A method for evaluating reactive support capability of a grid-connected wind turbine generator system according to claim 1, characterized in that: If the change in the amplitude of the steady-state reactive current 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 indicates the change of steady-state reactive current amplitude of the unit under test after the disturbance, K1 is the reactive current coefficient before the upper limit of strong excitation, K2 is the reactive current coefficient after the upper limit of strong excitation, β is the active power correction coefficient, P0 indicates the steady-state output value of active power of the unit under test before the disturbance, U indicates the terminal voltage amplitude of the unit under test, U ch Indicates the upper limit voltage of forced excitation.

3. 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 according to the response time.

4. 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 low voltage ride-through evaluation method, including: 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.

5. 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 high voltage ride-through evaluation method, comprising: increasing the terminal voltage of the unit to be tested, and evaluating the high voltage ride-through capability of the unit to be tested based on whether the unit to be tested maintains continuous operation without being disconnected from the grid within the voltage increase range.

6. 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 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.

7. 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 to be tested 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 to be tested after the disturbance; 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 position 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.

8. An electronic device, characterized in that: The invention 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 6.

9. 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 6.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images