A ground experiment platform grid-connected performance test method, device, equipment and medium

Abstract

The application discloses a ground experiment platform grid-connected performance test method and device, equipment and medium, relates to the wind turbine generator set grid-connected test field, and the method comprises the steps of constructing a wind turbine generator set grid-connected model according to an actual wind turbine generator set on a ground experiment platform; controlling a virtual power grid end in the wind turbine generator set grid-connected model to generate different power grid voltage fault working conditions and adverse power grid working conditions; performing fault performance virtual testing on the wind turbine generator set grid-connected model under different power grid voltage fault working conditions; and performing grid-connected adaptability virtual testing on the wind turbine generator set grid-connected model under different adverse power grid working conditions. The application can realize wind turbine generator set ground experiment platform grid-connected performance testing, has low cost, and can accurately test the wind turbine generator set grid-connected safe and stable operation level.

Description

Technical Field

[0001] This application relates to the field of grid connection testing of wind turbine units, and in particular to a method, apparatus, equipment and medium for testing the grid connection performance of a ground-based experimental platform. Background Technology

[0002] The trend towards larger offshore wind turbines is towards larger individual units, effectively reducing the construction costs of offshore wind farms. Currently, the industry lacks sufficient testing capabilities for the grid-connected performance of large-capacity offshore wind turbines. Actual grid-connected testing of large-capacity offshore wind turbines is prohibitively expensive and susceptible to environmental interference. Therefore, ground-based testing platforms are being considered for testing the grid-connected performance of offshore wind power. Ground-based testing platforms can simulate different grid conditions to conduct grid-connected tests on large-capacity offshore wind turbines, verifying their safe and stable grid-connected operation. However, how to implement grid-connected performance testing of wind turbines using ground-based testing platforms remains a pressing issue. Summary of the Invention

[0003] The purpose of this application is to provide a method, apparatus, equipment and medium for testing the grid connection performance of a ground test platform, which can realize the grid connection performance testing of wind turbine ground test platforms, with low cost and can accurately verify the safe and stable operation level of wind turbine grid connection.

[0004] To achieve the above objectives, this application provides the following solution:

[0005] Firstly, this application provides a method for testing the grid connection performance of a ground-based experimental platform, including:

[0006] A wind turbine grid-connected model is constructed based on the actual wind turbine on the ground test platform. The wind turbine grid-connected model includes: a wind turbine end and a virtual grid end. The wind turbine end includes: a model of the wind turbine under test. The virtual grid end includes: an ideal three-phase voltage source.

[0007] The virtual grid terminal in the wind turbine grid connection model is controlled to generate different grid voltage fault conditions and severe grid conditions; the grid voltage fault conditions include: grid voltage rise conditions and grid voltage drop conditions; the severe grid conditions include: voltage deviation conditions, frequency deviation conditions, three-phase voltage imbalance conditions, and harmonic voltage conditions.

[0008] The grid-connected model of the wind turbine was subjected to virtual fault performance tests under different grid voltage fault conditions to obtain virtual fault performance test results; the virtual fault performance test results are used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform.

[0009] The wind turbine grid-connected model is subjected to virtual testing of grid-connection adaptability under different severe grid conditions, and virtual testing results of grid-connection adaptability are obtained; the virtual testing results of grid-connection adaptability are used to represent the grid-connection adaptability of the actual wind turbine on the ground test platform.

[0010] In a second aspect, the present application provides a ground test platform grid-connection performance testing device, comprising:

[0011] A wind turbine grid-connected model construction module is configured to construct a wind turbine grid-connected model according to an actual wind turbine on a ground test platform; the wind turbine grid-connected model comprises a wind turbine end and a virtual grid end; the wind turbine end comprises a wind turbine model under test; and the virtual grid end comprises an ideal three-phase voltage source.

[0012] A grid condition generation module is configured to control the virtual grid end of the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions; the grid voltage fault conditions comprise a grid voltage rise condition and a grid voltage drop condition; and the severe grid conditions comprise a voltage deviation condition, a frequency deviation condition, a three-phase voltage imbalance condition and a harmonic voltage condition.

[0013] A fault performance virtual testing module is configured to perform virtual testing of fault performance of the wind turbine grid-connected model under different grid voltage fault conditions, and obtain virtual testing results of fault performance; the virtual testing results of fault performance are used to represent the fault ride-through capability of the actual wind turbine on the ground test platform.

[0014] A grid-connection adaptability virtual testing module is configured to perform virtual testing of grid-connection adaptability of the wind turbine grid-connected model under different severe grid conditions, and obtain virtual testing results of grid-connection adaptability; the virtual testing results of grid-connection adaptability are used to represent the grid-connection adaptability of the actual wind turbine on the ground test platform.

[0015] In a third aspect, the present application provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the ground test platform grid-connection performance testing method of any one of the above.

[0016] In a fourth aspect, the present application provides a computer readable storage medium having a computer program stored thereon, wherein the computer program is executable by a processor to implement the ground test platform grid-connection performance testing method of any one of the above.

[0017] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0018] The application provides a ground experiment platform grid-connected performance test method, device, equipment and medium. A wind turbine grid-connected model is constructed according to actual wind turbines on a ground experiment platform, different grid voltage fault conditions and severe grid conditions are generated through control of a virtual grid end in the wind turbine grid-connected model, virtual test of fault performance of the wind turbine grid-connected model under different grid voltage fault conditions is realized, and virtual test of grid-connected adaptability of the wind turbine grid-connected model under different severe grid conditions is realized. The application realizes virtual test of grid-connected performance of the ground experiment platform of the wind turbine, avoids real machine grid-connected test on large-capacity offshore wind turbines, has low cost, and will not be disturbed by environmental factors. Therefore, the application can verify the safe and stable operation level of the wind turbine grid-connected at low cost and accurately. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 An application environment diagram of a ground experiment platform grid-connected performance test method in an embodiment of the present application;

[0021] Figure 2 A flowchart of a ground experiment platform grid-connected performance test method provided by an embodiment of the present application;

[0022] Figure 3 A structure diagram of a wind turbine model to be tested provided by an embodiment of the present application;

[0023] Figure 4 A structure diagram of a wind turbine grid-connected model provided by an embodiment of the present application;

[0024] Figure 5 A voltage fault ride-through curve diagram provided by an embodiment of the present application;

[0025] Figure 6 A fault ride-through virtual test process diagram provided by an embodiment of the present application;

[0026] Figure 7 A grid-connected performance virtual test process diagram provided by an embodiment of the present application;

[0027] Figure 8 A functional module diagram of a ground experiment platform grid-connected performance test device provided by another embodiment of the present application;

[0028] Figure 9 A structural schematic diagram of a computer device is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0030] The above purposes, features and advantages of the present application can be more obvious and easy to understand. The present application will be described in further detail below with reference to the drawings and specific embodiments.

[0031] The wind turbine generator set grid-connected system of the ground test platform is digitally modeled in the embodiments of the present application, and the grid-connected performance is virtually tested under different grid conditions. The dynamic performance simulation results of the wind turbine generator set under different grid conditions can be obtained, which provides simulation reference for the test of the actual grid-connected system of the ground test platform. Whether the grid-connected control system of the ground test platform is effective under different grid conditions can be tested, which provides a model verification platform for the optimization of the grid-connected control strategy and the grid-connected protection system of the ground test platform.

[0032] The ground test platform grid-connected performance test method provided in the embodiments of the present application can be applied to, for example Figure 1The application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data required by the server 104 to process. The data storage system can be set up separately, or integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the wind turbine grid-connected model to the server 104, and the server 104 receives the wind turbine grid-connected model. For the wind turbine grid-connected model, the server 104 controls the virtual power grid end in the wind turbine grid-connected model to generate different grid voltage fault conditions and adverse grid conditions; the wind turbine grid-connected model is tested for fault performance under different grid voltage fault conditions, and the fault performance virtual test result is obtained; the wind turbine grid-connected model is tested for grid adaptability under different adverse grid conditions, and the grid adaptability virtual test result is obtained. The server 104 can feed back the obtained fault performance virtual test result and grid adaptability virtual test result to the terminal 102. In addition, in some embodiments, the ground experiment platform grid-connected performance test method can also be implemented by the server 104 or the terminal 102 alone, such as being directly processed by the terminal 102 for the wind turbine grid-connected model, or being processed by the server 104 for the wind turbine grid-connected model obtained from the data storage system.

[0033] Among them, the terminal 102 can be, but not limited to, various desktop computers, notebook computers, smart phones, tablet computers, Internet of Things devices and portable wearable devices. The Internet of Things device can be a smart speaker, a smart television, a smart air conditioner, a smart vehicle device, etc. The portable wearable device can be a smart watch, a smart bracelet, a head-mounted device, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0034] In an exemplary embodiment, as Figure 2 shown, a ground experiment platform grid-connected performance test method is provided, which is executed by a computer device, specifically, can be executed by a terminal or a server, etc. Computer device alone, or can be executed by a terminal and a server together, in the embodiment of the application, taking the server 104 in the Figure 1 application environment as an example for illustration, including the following steps 201 to 204. Among them:

[0035] Step 201, constructing a wind turbine grid-connected model according to an actual wind turbine on a ground experiment platform.

[0036] Among them, the wind turbine grid-connected model includes: a wind turbine end and a virtual power grid end; the wind turbine end includes: a measured wind turbine model; the virtual power grid end includes: an ideal three-phase voltage source.

[0037] Step 202, controlling the virtual grid end in the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions.

[0038] The grid voltage fault conditions include grid voltage rise conditions and grid voltage drop conditions; and the severe grid conditions include voltage deviation conditions, frequency deviation conditions, three-phase voltage imbalance conditions and harmonic voltage conditions.

[0039] Step 203, performing a fault performance virtual test on the wind turbine grid-connected model under different grid voltage fault conditions to obtain a fault performance virtual test result.

[0040] The fault performance virtual test result is used to represent the fault ride-through capability of the actual wind turbine on the ground test platform.

[0041] Step 204, performing a grid-connected adaptability virtual test on the wind turbine grid-connected model under different severe grid conditions to obtain a grid-connected adaptability virtual test result.

[0042] The grid-connected adaptability virtual test result is used to represent the grid-connected adaptability of the actual wind turbine on the ground test platform.

[0043] Implementing the above steps 201 to 204 can realize the wind turbine ground test platform grid-connected performance test, which is low in cost and can accurately test the wind turbine grid-connected safe and stable operation level.

[0044] In another exemplary embodiment of the present application, step 201 specifically includes:

[0045] (1) constructing a measured wind turbine model according to the actual wind turbine on the ground test platform; the measured wind turbine model includes a transmission chain mechanical model and a generator electrical model; the generator electrical model is connected with a functional model interface (FMI) through a zero-order holder; and the transmission chain mechanical model is connected with the FMI through a delay register. The structure of the measured wind turbine model is shown in Figure 3 .

[0046] (2) connecting the measured wind turbine model, the filter equivalent resistance R2 and the filter equivalent inductance L2 in sequence to form the wind turbine end; connecting the ideal three-phase voltage source, the grid-side equivalent resistance R1 and the grid-side equivalent inductance L1 in sequence to form the virtual grid end; connecting the grid-side equivalent inductance of the virtual grid end to the point of common coupling (PCC) through a transformer, and connecting the filter equivalent inductance in the wind turbine end to the point of common coupling (PCC) to obtain the wind turbine grid-connected model. The structure of the wind turbine grid-connected model is shown in Figure 4 .

[0047] In another exemplary embodiment of the present application, first, a measured wind turbine model is constructed, then a wind turbine grid-connected model is built based on the measured wind turbine model, and finally, simulation tests are performed on the wind turbine grid-connected model under various grid operating conditions, and the grid-connected performance of the wind turbine used by the ground test platform is evaluated according to the test results.

[0048] The present embodiment mainly further introduces the construction process of the measured wind turbine model.

[0049] Still referring to Figure 2 , the measured wind turbine model is built according to the mechanism of the actual wind turbine used by the ground test platform. The electrical part of the measured wind turbine model is built in MATLAB / Simulink with a simulation step of 5e-5s, and the mechanical part is built in Simpack with a simulation step of 0.02s. The generator electrical model outputs the electromagnetic torque parameter, and the transmission chain mechanical model outputs the speed and mechanical torque parameters, which are interacted through the FMI interface. The generator electrical model is a doubly-fed generator model, which includes the calculation formulas of stator current, rotor current and electromagnetic torque.

[0050] The transmission chain mechanical model of the measured wind turbine model is a two-mass model of the transmission chain, which includes the calculation formulas of the wind wheel mass block speed and the generator rotor mass block speed, and the mechanical relationship between the two mass blocks is defined by formulas (1)-(4), and the mechanical relationship between the two mass blocks is taken as the expression of the transmission chain mechanical model, as follows:

[0051]

[0052] T s =K s ∫(ω t -ω sl )dt+B s (ω t -ω sl ) (2)

[0053]

[0054] where J r represents the equivalent inertia of the wind wheel; J g represents the inertia of the generator rotor; T m represents the mechanical torque of the wind wheel, the value of which is set according to the virtual test content; T s represents the torque of the transmission shaft; T h represents the mechanical torque of the generator; T e represents the electromagnetic torque of the generator, which is provided by the engine electrical model; ω t represents the angular velocity of the wind wheel mass block; ω sl represents the angular velocity of the low-speed shaft of the transmission chain; ω r represents the angular velocity of the generator rotor; D r represents the damping coefficient of the wind wheel; D g represents the damping coefficient of the generator rotor; B s represents the equivalent damping coefficient of the shafting of the transmission shaft; K s represents the equivalent stiffness coefficient of the shafting of the transmission shaft; N represents the gear box transmission ratio; ω w represents the variable wind wheel speed; t represents time.

[0055] The generator electrical model of the measured wind turbine model comprises: a doubly-fed generator model, the stator and rotor currents of which are represented by a four-order model in a dq rotating coordinate system. The generator rotor speed and input mechanical torque of the generator electrical model are provided by a two-mass block model of the transmission chain, and the stator voltage and rotor voltage are provided by an ideal three-phase voltage source. The doubly-fed generator model comprises: a stator current parameter calculation expression, a rotor current parameter calculation expression, and an electromagnetic torque expression.

[0056] Specifically, the stator current parameter calculation expression is shown in formula (5), and the rotor current parameter calculation expression is shown in formula (6), and the stator and rotor currents can be controlled by adjusting the rotor-side voltage.

[0057]

[0058]

[0059] In the formula, u ds , u qs , u dr , u qr are voltage components of the stator and rotor in the dq coordinate system; i ds , i qs , i dr , i qr are current components of the stator and rotor in the dq coordinate system; R s , R rrespectively, are stator resistance and rotor resistance; ω s is synchronous angular velocity; p is the pole pair number of the generator; L s , L r are stator and rotor self-inductance; L ls , L lr are stator and rotor leakage inductance; L m is the mutual inductance of the generator.

[0060] The electromagnetic torque expression of the doubly-fed generator model is shown in equation (7).

[0061]

[0062] The active power P and the reactive power Q of the doubly-fed generator model are calculated by equation (8).

[0063]

[0064] By adjusting the stator current component and the rotor current component, the electromagnetic torque adjustment value is satisfied , and the variables of equation (1) and equation (4), i.e., the wind rotor speed ω w and the rotor speed ω r , are calculated to converge. When the wind rotor speed ω w and the rotor speed ω r converge, the stable stator voltage component, the rotor voltage component, the stator current component, and the rotor current component u ds , u qs , u dr , u qr , i ds , i qs , i dr , i qr of the doubly-fed generator model are obtained, and u ds , u qs , u dr , u qr , i ds , i qs , i dr , i qr are brought into equation (8) to calculate the active power and the reactive power of the doubly-fed generator model.

[0065] To realize the real-time interaction of data between the generator electrical model and the transmission chain mechanical model with different simulation steps, refer to Figure 1 for data processing. First, the initial active power and the initial reactive power of the generator electrical model, the initial stator voltage and the initial rotor voltage are set, the initial values of the stator current and the rotor current are calculated by bringing them into equation (8), and the initial value of the electromagnetic torque T e is calculated by equation (7). The electromagnetic torque Te After the zero-order holder processing, the rectangular wave which meets the simulation step of the mechanical model of the drive train is formed, and is output to the mechanical model of the drive train with large step through the FMI protocol; then, the electromagnetic torque T e After the initial data, the corresponding wind rotor speed ω t , the generator mechanical torque T h and the generator rotor speed ω r are calculated by formula (1) - formula (4). h The delay register updates the stored mechanical torque T r and the generator rotor speed ω h simulation data; finally, the generator electrical model reads the T r , ω e data in the register through the FMI interface, and calculates the electromagnetic torque T j simulation data of the next simulation period by formula (5) - formula (7).

[0066] The wind turbine grid-connected model is built in MATLAB / Simulink to simulate the grid-connected characteristics of the actual wind turbine. The wind turbine grid-connected model is divided into a virtual grid end and a wind turbine end. The virtual grid end is composed of an ideal three-phase voltage source U j and a grid-side equivalent resistance R1 and inductance L1 in series; the wind turbine end is composed of a measured wind turbine model, a filter equivalent resistance R2 and inductance L2 in series.

[0067] The voltage value U o of each term of the ideal three-phase voltage source is calculated by formula (9).

[0068]

[0069] In the formula, U N is the rated voltage amplitude of the grid, f(t) is the grid frequency, is the initial phase angle.

[0070] The wind turbine grid-connected model simulates the grid-connected characteristics of the wind turbine under different AC grid strengths by adjusting the values of the short-circuit ratio SCR and the impedance ratio. The definitions of the short-circuit ratio and the impedance ratio are shown in formula (10) and formula (11).

[0071]

[0072] In the formula, V N and P dn are the rated voltage of the grid and the rated active power of the wind turbine connected to the grid, respectively; L g and R gThe equivalent inductance value and the equivalent resistance value of the power grid. Formula (11) is used to describe the form of the harmonic voltage.

[0073] In another exemplary embodiment of the present application, in step 202, the virtual grid end of the wind turbine grid-connected model can generate different special grid operating conditions, including grid voltage fault and severe grid operating conditions. The grid voltage fault condition refers to the grid voltage drop or rise, and the severe grid operating condition refers to the voltage deviation, frequency deviation, three-phase voltage imbalance, and harmonic voltage in the grid.

[0074] Step 202 specifically includes:

[0075] (1) Grid voltage fault simulation method.

[0076] The virtual grid end of the wind turbine grid-connected model generates different types of voltage faults, and the wind turbine model performs different fault ride-through control according to the type of voltage fault. When simulating different types of grid voltage faults, the voltage variation range of the grid-connected point is all within the voltage region shown in the figure, and the wind turbine model does not disconnect from the grid and continuously operates. Figure 5

[0077] Specifically, different grid voltage fault conditions are generated at the virtual grid end of the wind turbine grid-connected model by controlling the fault parameters (such as generating different grid voltage rise conditions and voltage drop conditions at the virtual grid end of the wind turbine grid-connected model by setting the fault parameters), and the measured wind turbine model in the wind turbine grid-connected model responds to the fault type according to the set control parameters, thereby generating control actions corresponding to the grid voltage fault conditions. The fault parameters include: the voltage variation degree of the virtual grid end, the voltage fault duration, and the fault phase number; the control parameters include: the ride-through reactive power support coefficient (low voltage ride-through reactive power support coefficient, high voltage ride-through reactive power support coefficient) when the grid voltage fault occurs, the ride-through threshold voltage (low voltage ride-through threshold voltage, high voltage ride-through threshold voltage), and the current amplitude limit value.

[0078] (2) Severe grid operating condition simulation method.

[0079] Specifically, the voltage deviation condition is generated by setting the amplitude-time variation sequence of the ideal voltage source at the virtual grid end of the wind turbine grid-connected model; the frequency deviation condition is generated by setting the frequency-time variation sequence of the ideal voltage source at the virtual grid end of the wind turbine grid-connected model; the three-phase voltage imbalance condition is generated by introducing a negative sequence voltage component to the ideal voltage source at the virtual grid end of the wind turbine grid-connected model; and the harmonic voltage condition is generated by adding a harmonic sequence to the grid-connected point voltage of the wind turbine grid-connected model.

[0080] ​Further, the voltage deviation condition, the frequency deviation condition are generated by setting the amplitude and the frequency time variation sequence of the ideal voltage source of the virtual grid terminal in the wind turbine generator set grid-connected model; the three-phase voltage unbalance condition is generated by introducing the negative sequence voltage component of the three-phase voltage, and the negative sequence unbalance degree ranges from 0 to 10%; the grid harmonic voltage is generated by adding the harmonic sequence U j to the grid point voltage as shown in equation (12).

[0081]

[0082] wherein, A v is the harmonic amplitude of the v-th harmonic; n is the total harmonic number; f g is the grid working frequency; is the harmonic phase angle. The harmonic sequence frequency band is 2.5Hz-1250Hz, covering the harmonic and inter-harmonic of the working frequency, and the injected single harmonic and inter-harmonic voltage amplitude does not exceed 5%U N , U N is the grid rated voltage.

[0083] In another exemplary embodiment of the present application, step 203 specifically comprises:

[0084] (1) obtaining the grid point voltage amplitude of the measured wind turbine generator set model under the current grid voltage fault condition.

[0085] (2) judging whether the grid point voltage amplitude is out of the set voltage amplitude range.

[0086] If the grid point voltage amplitude is out of the set voltage amplitude range, the measured wind turbine generator set model is not off-grid, and the fault ride-through protection circuit is put into operation to limit the converter current and the DC bus voltage within the set maximum allowable value.

[0087] After the fault ride-through protection circuit is put into operation, the wind turbine generator set grid-connected model enters the fault ride-through state, and then the grid-connected active power and the grid-connected reactive power are adjusted until the grid point voltage amplitude is within the set voltage amplitude range, and the fault ride-through state ends; the fault performance virtual test result includes whether the wind turbine generator set grid-connected model is off-grid, the value of the converter current, the value of the DC bus voltage and the fault ride-through state duration.

[0088] The fault ride-through virtual test process in actual application will be further described in detail below. Figure 6

[0089] ​To verify the simulation performance of the tested wind turbine model for the high and low voltage ride-through of the actual wind turbine on the ground test platform, the three-phase symmetric and three-phase asymmetric voltage fault chain tests are carried out under the conditions that the active power output of the tested wind turbine model is 0.2 p.u and 0.9 p.u. The chain fault voltage working conditions used in the test are that the virtual grid end of the wind turbine grid-connected model first experiences voltage drop, the drop amplitude is 0.20 p.u, and the duration is 625 ms; after 10 ms of interval time, the virtual grid end experiences voltage rise, the rise amplitude is 1.30 p.u, and the duration is 500 ms. See Figure 6 The fault ride-through control flow adopted by the tested wind turbine model is as follows:

[0090] a) The virtual grid end of the wind turbine grid-connected model generates the corresponding grid voltage fault according to the fault parameters, the fault ride-through control program of the tested wind turbine model measures the voltage amplitude at the grid-connected point, and judges whether the tested wind turbine model performs the off-grid action according to whether the voltage amplitude at the grid-connected point is higher than 1.3 p.u or lower than 0.2 p.u.

[0091] b) If the judgment result is that the tested wind turbine model continues to operate in grid-connected mode, the fault ride-through protection circuit (including the crowbar circuit and the energy dissipation circuit) is put into operation to limit the current of the converter and the voltage of the DC bus within the maximum allowable value.

[0092] c) When the wind turbine is in the voltage fault period (i.e. in the fault ride-through state), the active power control program limits the active power fluctuation to ±5% P n , P n is the rated power, and the reactive current control program quickly responds to the grid-connected current demand to support voltage recovery by injecting or absorbing reactive current. The detailed reactive current control scheme is as follows:

[0093] When the positive sequence voltage component at the grid-connected point is lower than the low voltage ride-through threshold voltage, the tested wind turbine model supports the recovery of the virtual grid voltage by injecting reactive current, and the injected dynamic reactive current I T satisfies formula (13).

[0094] I T ≥K1*(0.9-U T )*I N ,(0.2≤U T ≤0.9) (13)

[0095] In the formula, K1 is the low voltage ride-through reactive support coefficient, K1 is not less than 1.5 and not greater than 3; U T is the grid-connected point voltage per unit value; and I N is the rated current of the wind turbine.

[0096] When the positive sequence voltage component of the grid-connected point is higher than the high voltage ride-through threshold voltage, the measured wind turbine model supports voltage recovery by actively absorbing reactive current T The formula (14) is met.

[0097] I T ≥K2*(U T -1.1)*I N ,(1.1≤U T ≤1.3) (14)

[0098] In the formula, K2 is a high voltage ride-through reactive support coefficient, and the value of K2 is not less than 1.5.

[0099] The above step c) specifically describes the adjustment process of the grid-connected active power and the grid-connected reactive power after the wind turbine grid-connected model enters the fault ride-through state after the fault ride-through protection circuit is put into operation.

[0100] d) After the duration of the grid fault ends, the model active power is restored to the output power corresponding to the actual wind condition at a speed of at least 0.1P n / s per second, and the model grid-connected reactive current is restored to the value before the fault.

[0101] According to the fault ride-through control process, the measured wind turbine fault ride-through capability estimation method is: (1) During the duration of the grid fault, it is judged whether the measured wind turbine model has been disconnected from the grid according to the voltage at the grid-connected point. If the voltage at the grid-connected point is zero, it means that the measured wind turbine model cannot maintain the grid-connected state during the duration of the grid fault, the model virtual test is failed, and the grid-connected relay capacity of the measured wind turbine may not be enough. (2) If the measured wind turbine model can maintain the fault grid-connected operation, it is detected whether the converter current and the DC bus voltage of the model exceed the maximum allowable value. If the maximum allowable value is exceeded, it means that the crowbar circuit and the energy dissipation circuit resistance of the measured wind turbine may be too small. (3) It is measured whether the reactive power injected or absorbed by the measured wind turbine model to the virtual grid at the grid-connected model during the grid fault meets the standard requirement. If it does not meet the requirement, the reactive power control program needs to be optimized. (4) It is measured whether the fluctuation amplitude of the active power during the voltage fault meets the amplitude limit value, and whether the recovery speed of the active power after the low voltage ride-through is observed reaches 0.1P n / s. If it does not meet the requirement, the active power control program needs to be optimized.

[0102] In another example embodiment of the present application, in step 204, before the actual wind turbine grid-connection adaptability test is performed on the ground test platform, a virtual test of the wind turbine grid-connection adaptability under severe grid conditions is performed on the wind turbine grid-connection model. Different disturbance conditions are set in the virtual grid end of the grid-connection model, and the simulation curves of the grid-connection electrical quantities of the wind turbine model under each grid disturbance condition are simulated and recorded, and the grid-connection performance of the actual wind turbine on the ground test platform is estimated according to the simulation data. The tested grid-connection performance includes voltage deviation adaptability, frequency deviation adaptability, grid background harmonic adaptability, and three-phase voltage imbalance adaptability.

[0103] Step 204 specifically includes:

[0104] In the voltage deviation condition, it is judged whether the tested wind turbine model is off-grid, if the tested wind turbine model is not off-grid, a first voltage deviation adaptability test result is recorded, if the tested wind turbine model is off-grid, a second voltage deviation adaptability test result is recorded, the first voltage deviation adaptability test result includes the waveform of the active power in the voltage deviation simulation test, and the second voltage deviation adaptability test result includes the duration of the voltage deviation simulation test, the off-grid time, and the electrical quantity waveform triggering the off-grid protection.

[0105] In the frequency deviation condition, it is judged whether the tested wind turbine model is off-grid, if the tested wind turbine model is not off-grid, a first frequency deviation adaptability test result is recorded, if the tested wind turbine model is off-grid, a second frequency deviation adaptability test result is recorded, the first frequency deviation adaptability test result includes the waveform of the grid-connection current frequency in the frequency deviation simulation test, and the second frequency deviation adaptability test result includes the duration of the frequency deviation simulation test, the off-grid time, and the electrical quantity waveform triggering the off-grid protection.

[0106] In the three-phase voltage imbalance condition, it is judged whether the tested wind turbine model is off-grid, if the tested wind turbine model is not off-grid, a first voltage imbalance adaptability test result is recorded, if the tested wind turbine model is off-grid, a second voltage imbalance adaptability test result is recorded, the first voltage imbalance adaptability test result includes the negative sequence imbalance degree of the grid-connection point voltage and the negative sequence imbalance degree of the grid-connection point current in the voltage imbalance simulation test, and the second voltage imbalance adaptability test result includes the duration of the voltage imbalance simulation test, the off-grid time, and the electrical quantity waveform triggering the off-grid protection.

[0107] Under the harmonic voltage working condition, it is judged whether the measured wind turbine model is off-grid, if the measured wind turbine model is not off-grid, a first harmonic voltage adaptability test result is recorded, if the measured wind turbine model is off-grid, a second harmonic voltage adaptability test result is recorded, the first harmonic voltage adaptability test result comprises: total harmonic distortion rate of grid-connected point voltage and total harmonic distortion rate of grid-connected point current in the harmonic voltage simulation test, and the second harmonic voltage adaptability test result comprises: duration of the harmonic voltage simulation test, off-grid time and electrical quantity waveform triggering off-grid protection.

[0108] The grid-connected adaptability virtual test result comprises: first voltage deviation adaptability test result, second voltage deviation adaptability test result, first frequency deviation adaptability test result, second frequency deviation adaptability test result, first voltage imbalance adaptability test result, second voltage imbalance adaptability test result, first harmonic voltage adaptability test result and second harmonic voltage adaptability test result.

[0109] The grid-connected adaptability virtual test process in actual application is further described below.

[0110] 1. Voltage deviation adaptability.

[0111] The wind turbine model wind rotor mechanical torque T m Set to 0.2p.u, the following steps are used for simulation test.

[0112] a) The initial voltage of the power grid is set to rated value, the voltage amplitude is gradually reduced at the amplitude of 1% rated voltage under rated frequency, the voltage is raised by 0.01p.u every 20s. After the voltage is raised to 1.10p.u, the voltage value is kept unchanged for 10min. It is tested whether the measured wind turbine model can normally operate in grid-connected mode, if it can normally operate, the waveform of active power in simulation test is measured and recorded, if the measured wind turbine model is off-grid, the simulation test duration, off-grid time and electrical quantity waveform triggering off-grid protection are recorded.

[0113] b) The initial voltage of the power grid is set to rated value, the voltage amplitude is gradually reduced at the amplitude of 1% rated voltage under rated frequency, the voltage is reduced by 0.01p.u every 20s. After the voltage is reduced to 0.90p.u, the voltage value is kept unchanged for 10min. It is tested whether the measured wind turbine model can normally operate in grid-connected mode, if it can normally operate, the waveform of active power in simulation test is measured and recorded, if the measured wind turbine model is off-grid, the simulation test duration, off-grid time and electrical quantity waveform triggering off-grid protection are recorded.

[0114] 2. Frequency deviation adaptability.

[0115] The wind turbine model wind rotor mechanical torque Tm Set the value to 0.2 pu and perform simulation testing using the following steps.

[0116] a) Set the voltage frequency of the virtual grid terminal of the grid-connected model to 50Hz. Gradually increase the voltage frequency by 0.1Hz every 20 seconds at the rated voltage. Increase the frequency until it reaches the highest allowable operating frequency of the wind turbine under test, then maintain this highest frequency for 1 minute. Test whether the wind turbine model can operate normally in grid connection. If it can operate normally, measure and record the waveform of the grid-connected current frequency during the simulation test. If the wind turbine model is disconnected from the grid, record the simulation test duration, the disconnection time, and the electrical quantity waveform that triggers the disconnection protection.

[0117] b) Set the voltage frequency of the virtual grid terminal of the grid-connected model to 50Hz. Gradually decrease the voltage frequency by 0.1Hz every 20 seconds at the rated voltage. Reduce the frequency to the minimum allowable operating frequency of the wind turbine under test, then maintain this minimum frequency for 1 minute. Test whether the wind turbine model can operate normally in grid connection. If it can operate normally, measure and record the waveform of the grid-connected current frequency during the simulation test. If the wind turbine model disconnects from the grid, record the simulation test duration, disconnection time, and the electrical waveform that triggers the disconnection protection.

[0118] 3. Adaptability to background harmonics in the power grid.

[0119] The mechanical torque T of the wind turbine model under test m Set the voltage to 0.5 pu and allow the wind turbine model under test to operate normally at rated voltage and frequency. Then, add background harmonics to the virtual grid terminal of the grid-connected model for 2 minutes. The frequency, amplitude, and phase angle of the harmonic sequence are set according to the measured values ​​of the ground test platform, and the harmonic content does not exceed 3%. Test whether the wind turbine model under test can operate normally in grid connection. If it can operate normally, measure and record the total harmonic distortion rate of the voltage and current at the grid connection point during the simulation test. If the wind turbine model under test is disconnected from the grid, record the simulation test duration, disconnection time, and electrical waveforms that trigger the disconnection protection.

[0120] 4. Three-phase voltage imbalance adaptability.

[0121] The mechanical torque T of the wind turbine model under test m Set the value to 0.5 pu and perform simulation testing using the following steps.

[0122] a) Let the measured wind turbine model run normally at rated voltage and rated frequency, then adjust the voltage amplitude of each phase to make the virtual grid end output of the grid-connected model 2.0% negative sequence voltage unbalance for 30 minutes. Test whether the measured wind turbine model can run normally, if it can run normally, measure and record the negative sequence unbalance of the voltage and current at the grid connection point in the simulation test; if the measured wind turbine model is off-grid, record the duration of the simulation test, the off-grid time and the electrical quantity waveform triggering the off-grid protection.

[0123] b) Let the measured wind turbine model run normally at rated voltage and rated frequency, then adjust the voltage amplitude of each phase to make the virtual grid end output of the grid-connected model 4.0% negative sequence voltage unbalance for 1 minute. Test whether the measured wind turbine model can run normally, if it can run normally, measure and record the negative sequence unbalance of the voltage and current at the grid connection point in the simulation test; if the measured wind turbine model is off-grid, record the duration of the simulation test, the off-grid time and the electrical quantity waveform triggering the off-grid protection.

[0124] The above steps 203 and 204 of the embodiment realize virtual testing of grid-connection performance, as shown in Figure 7 According to the ground test platform grid-connection safety checking method, the simulation system performs virtual testing of the grid-connection performance of the measured wind turbine model used in the ground test, the test content is fault ride-through capability and grid-connection adaptability in severe grid conditions, the measured wind turbine model used in the virtual testing is built according to the wind turbine used in the ground test platform, and the simulation accuracy can reach more than 85%. The simulation system refers to the rated safety parameter threshold of each electrical element of the platform, and feeds back the working condition of the model electrical element exceeding the safety threshold in the virtual testing to the ground test platform, so as to realize the estimation of the fault ride-through capability and grid-connection adaptability of the wind turbine of the ground test platform.

[0125] The embodiment of the application realizes a ground test platform grid-connection performance virtual testing method based on a wind turbine grid-connection model. The wind turbine grid-connection model includes a measured wind turbine model, an ideal three-phase voltage source, a grid measurement equivalent resistance element, a grid measurement equivalent inductance element, a filter equivalent resistance element and a filter equivalent inductance element. The measured wind turbine model is built according to the wind turbine used in the ground test platform, the wind turbine grid-connection model can simulate the grid-connection characteristics according to different grid conditions set according to the grid-connection performance test content, and the grid-connection capability of the wind turbine used in the ground test platform is estimated according to the simulation result, so as to provide data reference for the grid-connection performance analysis of the wind turbine actually running in the ground test platform.

[0126] Specifically, a modeling method of a ground test platform wind turbine model is designed, data interaction between models with different simulation steps is realized, and the simulation results can simulate the coupling relationship between mechanical quantities and electrical quantities. In view of the problem of large difference between the simulation steps of the mechanical model and the electrical model of the wind turbine to be tested, a delay register and a zero-order sampler are used to process the interaction data of the two, so as to realize the real-time data interaction between them; a virtual test method based on the grid-connected model of the wind turbine is also designed, different voltage fault and severe grid conditions of the grid-connected model of the wind turbine are set according to the virtual test content, the low-voltage ride-through capability and grid adaptability simulation virtual test of the wind turbine model to be tested are carried out, and the grid-connected performance estimation is provided before the actual test on the ground test platform.

[0127] Based on the same inventive concept, the embodiment of the present application also provides a ground test platform grid-connected performance test device for realizing the ground test platform grid-connected performance test method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more ground test platform grid-connected performance test device embodiments provided below can be referred to the limitations of the ground test platform grid-connected performance test method in the above, which will not be repeated here.

[0128] In one exemplary embodiment, as shown in Figure 8 a ground test platform grid-connected performance test device is provided, which includes:

[0129] A wind turbine grid-connected model construction module 801 is configured to construct a wind turbine grid-connected model according to an actual wind turbine on a ground test platform. The wind turbine grid-connected model includes a wind turbine end and a virtual grid end. The wind turbine end includes a wind turbine model to be tested. The virtual grid end includes an ideal three-phase voltage source.

[0130] A grid condition generation module 802 is configured to control the virtual grid end of the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions. The grid voltage fault conditions include a grid voltage rise condition and a grid voltage drop condition. The severe grid conditions include a voltage deviation condition, a frequency deviation condition, a three-phase voltage imbalance condition, and a harmonic voltage condition.

[0131] A fault performance virtual test module 803 is configured to perform fault performance virtual test on the wind turbine grid-connected model under different grid voltage fault conditions, and obtain fault performance virtual test results. The fault performance virtual test results are used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform.

[0132] The grid-adaptability virtual test module 804 is configured to perform virtual grid-adaptability tests on the wind turbine grid-connection model under different severe grid conditions to obtain virtual grid-adaptability test results, which are used to represent the grid-adaptability of the actual wind turbine on the ground test platform.

[0133] In an exemplary embodiment, a computer device, which can be a server or a terminal, is provided, and an internal structure diagram of the computer device can be as shown in FIG. 1. Figure 9 The computer device includes a processor, a memory, an input / output interface (I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for running the operating system and the computer program in the non-volatile storage medium. The database of the computer device is configured to store a wind turbine grid-connection model. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to communicate with external terminals through network connection. The computer program is executed by the processor to implement a ground test platform grid-connection performance test method.

[0134] Those skilled in the art can understand that Figure 9 The structure shown in FIG. 1 is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0135] In an exemplary embodiment, a computer device is also provided, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0136] In an exemplary embodiment, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0137] In an exemplary embodiment, a computer program product is provided, which includes a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0138] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. The non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. The volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.

[0139] The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a blockchain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, etc., without being limited thereto.

[0140] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0141] The principles and implementation modes of the present application are described by applying specific examples herein, and the above-mentioned embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the present application should not be understood as a limitation.

Claims

1. A method for grid-connected performance test of a ground test platform, characterized in that, The ground experiment platform grid-connected performance test method comprises: According to the actual wind turbine on the ground experiment platform, a wind turbine grid-connected model is constructed; the wind turbine grid-connected model comprises: a wind turbine end and a virtual power grid end; the wind turbine end comprises: a measured wind turbine model; the virtual power grid end comprises: an ideal three-phase voltage source; The virtual power grid end in the wind turbine grid-connected model is controlled to generate different grid voltage fault working conditions and severe grid working conditions; the grid voltage fault working conditions comprise: a grid voltage rise working condition and a grid voltage drop working condition; the severe grid working conditions comprise: a voltage deviation working condition, a frequency deviation working condition, a three-phase voltage imbalance working condition and a harmonic voltage working condition; The wind turbine grid-connected model is subjected to fault performance virtual testing under different grid voltage fault working conditions, and fault performance virtual testing results are obtained; the fault performance virtual testing results are used to represent the fault ride-through capability of the actual wind turbine on the ground experiment platform; The wind turbine grid-connected model is subjected to grid-connected adaptability virtual testing under different severe grid working conditions, and grid-connected adaptability virtual testing results are obtained; the grid-connected adaptability virtual testing results are used to represent the grid-connected adaptability of the actual wind turbine on the ground experiment platform.

2. The method of claim 1, wherein, According to the actual wind turbine on the ground experiment platform, a wind turbine grid-connected model is constructed, specifically comprising: According to the actual wind turbine on the ground experiment platform, a measured wind turbine model is constructed; the measured wind turbine model comprises: a transmission chain mechanical model and a generator electrical model; the generator electrical model is connected with an FMI interface through a zero-order holder; the transmission chain mechanical model is connected with the FMI interface through a delay register; The measured wind turbine model, a filter equivalent resistance and a filter equivalent inductance are connected in sequence to form the wind turbine end; The ideal three-phase voltage source, a grid-side equivalent resistance and a grid-side equivalent inductance are connected in sequence to form the virtual power grid end; The grid-side equivalent inductance of the virtual power grid end is connected with a point of common coupling through a transformer, and the filter equivalent inductance in the wind turbine end is connected with the point of common coupling, to obtain the wind turbine grid-connected model.

3. The method of claim 1, wherein, The virtual power grid end in the wind turbine grid-connected model is controlled to generate different grid voltage fault working conditions and severe grid working conditions, specifically comprising: The virtual power grid end in the wind turbine grid-connected model is controlled to generate different grid voltage fault working conditions by controlling fault parameters; the measured wind turbine model in the wind turbine grid-connected model responds to the fault type according to control parameters, thereby generating control actions corresponding to the grid voltage fault working conditions; the fault parameters comprise: a voltage variation degree of the virtual power grid end, a voltage fault duration and a fault phase number; the control parameters comprise: a ride-through reactive power support coefficient, a ride-through threshold voltage and a current amplitude limiting value when the grid voltage fails; A voltage deviation working condition is generated by setting an amplitude-time variation sequence for the ideal voltage source of the virtual power grid end in the wind turbine grid-connected model; A frequency deviation working condition is generated by setting a frequency-time variation sequence for the ideal voltage source of the virtual power grid end in the wind turbine grid-connected model; The negative sequence voltage component is introduced into the ideal voltage source of the virtual grid terminal in the wind turbine grid-connected model to generate a three-phase voltage imbalance condition; The harmonic sequence is added to the grid-connected point voltage in the wind turbine grid-connected model to generate a harmonic voltage condition.

4. The method of claim 1, wherein, The wind turbine grid-connected model is tested for fault performance under different grid voltage fault conditions to obtain fault performance virtual test results, which specifically include: The grid-connected point voltage amplitude of the tested wind turbine model under the current grid voltage fault condition is obtained; It is determined whether the grid-connected point voltage amplitude is outside the set voltage amplitude range; If the grid-connected point voltage amplitude is outside the set voltage amplitude range, the tested wind turbine model is not off-grid, and the fault ride-through protection circuit is put into operation to limit the converter current and DC bus voltage within the set maximum allowable value; After the fault ride-through protection circuit is put into operation, the wind turbine grid-connected model enters a fault ride-through state, and the grid-connected active power and grid-connected reactive power are adjusted until the grid-connected point voltage amplitude is within the set voltage amplitude range, and the fault ride-through state ends; the fault performance virtual test results include whether the wind turbine grid-connected model is off-grid, the value of the converter current, the value of the DC bus voltage, and the duration of the fault ride-through state.

5. The method of claim 1, wherein, The wind turbine grid-connected model is tested for grid-connected adaptability under different severe grid conditions to obtain grid-connected adaptability virtual test results, which specifically include: Under the voltage deviation condition, it is determined whether the tested wind turbine model is off-grid, and if the tested wind turbine model is not off-grid, a first voltage deviation adaptability test result is recorded; if the tested wind turbine model is off-grid, a second voltage deviation adaptability test result is recorded; the first voltage deviation adaptability test result includes the active power waveform in the voltage deviation simulation test; the second voltage deviation adaptability test result includes the duration of the voltage deviation simulation test, the off-grid time, and the electrical quantity waveform triggering the off-grid protection; Under the frequency deviation condition, it is determined whether the tested wind turbine model is off-grid, and if the tested wind turbine model is not off-grid, a first frequency deviation adaptability test result is recorded; if the tested wind turbine model is off-grid, a second frequency deviation adaptability test result is recorded; the first frequency deviation adaptability test result includes the grid-connected current frequency waveform in the frequency deviation simulation test; the second frequency deviation adaptability test result includes the duration of the frequency deviation simulation test, the off-grid time, and the electrical quantity waveform triggering the off-grid protection; In the three-phase voltage imbalance condition, it is judged whether the measured wind turbine model is off-grid, if the measured wind turbine model is not off-grid, the first voltage imbalance adaptability test result is recorded, if the measured wind turbine model is off-grid, the second voltage imbalance adaptability test result is recorded, the first voltage imbalance adaptability test result includes: negative sequence imbalance degree of grid-connected point voltage and negative sequence imbalance degree of grid-connected point current in the voltage imbalance simulation test, the second voltage imbalance adaptability test result includes: duration of the voltage imbalance simulation test, off-grid time and electrical quantity waveform triggering off-grid protection; In the harmonic voltage condition, it is judged whether the measured wind turbine model is off-grid, if the measured wind turbine model is not off-grid, the first harmonic voltage adaptability test result is recorded, if the measured wind turbine model is off-grid, the second harmonic voltage adaptability test result is recorded, the first harmonic voltage adaptability test result includes: total harmonic distortion rate of grid-connected point voltage and total harmonic distortion rate of grid-connected point current in the harmonic voltage simulation test, the second harmonic voltage adaptability test result includes: duration of the harmonic voltage simulation test, off-grid time and electrical quantity waveform triggering off-grid protection; The grid-connected adaptability virtual test result includes: first voltage deviation adaptability test result, second voltage deviation adaptability test result, first frequency deviation adaptability test result, second frequency deviation adaptability test result, first voltage imbalance adaptability test result, second voltage imbalance adaptability test result, first harmonic voltage adaptability test result and second harmonic voltage adaptability test result.

6. The method of claim 2, wherein, The expression of the transmission chain mechanical model is: where J r represents the equivalent inertia of the wind wheel; J g represents the inertia of the generator rotor; T m represents the mechanical torque of the wind wheel; T s represents the torque of the transmission shaft; T h represents the mechanical torque of the generator; T e represents the electromagnetic torque of the generator; ω t represents the angular velocity of the wind wheel mass; ω sl represents the angular velocity of the low-speed shaft of the transmission chain; ω r represents the angular velocity of the generator rotor; D r represents the damping coefficient of the wind wheel; D g represents the damping coefficient of the generator rotor; B s represents the equivalent damping coefficient of the shafting of the transmission shaft; K s represents the equivalent stiffness coefficient of the shafting of the transmission shaft; N represents the gear box transmission ratio; ω w represents the variable wind wheel speed; t represents time.

7. The method of claim 2, wherein, The generator electrical model includes: a doubly-fed generator model, the doubly-fed generator model includes: a stator current parameter calculation expression, a rotor current parameter calculation expression and an electromagnetic torque expression.

8. A ground test platform grid-connection performance testing device, characterized in that, The grid-connected performance test device of the ground experiment platform includes: A wind turbine grid-connected model construction module is configured to construct a wind turbine grid-connected model according to an actual wind turbine on the ground experiment platform, the wind turbine grid-connected model includes: a wind turbine end and a virtual grid end, the wind turbine end includes: a measured wind turbine model, the virtual grid end includes: an ideal three-phase voltage source; A grid condition generation module is configured to control the virtual grid end in the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions, the grid voltage fault conditions include: a grid voltage rise condition and a grid voltage drop condition, the severe grid conditions include: a voltage deviation condition, a frequency deviation condition, a three-phase voltage imbalance condition and a harmonic voltage condition; A fault performance virtual test module is configured to perform fault performance virtual test on the wind turbine grid-connected model in different grid voltage fault conditions to obtain fault performance virtual test results, the fault performance virtual test results are used to represent fault ride-through capability of the actual wind turbine on the ground experiment platform. A grid-adaptability virtual testing module is configured to perform grid-adaptability virtual testing on the grid-connection model of the wind turbine under different severe grid conditions to obtain grid-adaptability virtual testing results, which are used to represent the grid-adaptability of the actual wind turbine on the ground test platform.

9. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the ground test platform grid-connection performance testing method of any one of claims 1-7.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the ground test platform grid-connection performance testing method of any one of claims 1-7.

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