Ground experimental platform grid-connected performance test method, device, equipment and medium

Abstract

The invention discloses a ground experiment platform grid-connected performance testing method, device and equipment and a medium, and relates to the field of wind turbine generator grid-connected testing, and the method comprises the steps: constructing a wind turbine generator grid-connected model according to an actual wind turbine generator on a ground experiment platform; controlling a virtual power grid end in the wind turbine generator grid-connected model to generate different power grid voltage fault working conditions and severe power grid working conditions; fault performance virtual testing is carried out on the wind turbine generator grid-connected model under different power grid voltage fault working conditions; the grid-connected adaptability virtual test is performed on the wind turbine generator grid-connected model under different severe power grid working conditions, the grid-connected performance test of the wind turbine generator ground experiment platform can be realized, the cost is low, and the safe and stable operation level of the wind turbine generator grid-connected can be accurately tested.

Description

Technical Field

[0001] The present application relates to the field of wind turbine grid-connected testing, and in particular to a method, device, equipment and medium for testing grid-connected performance of a ground experimental platform. Background Art

[0002] The large-scale development of offshore wind turbines is a trend in the development of offshore wind power generation, which can effectively reduce the construction cost of offshore wind farms. At present, the industry lacks the testing of the grid-connected performance of large-capacity offshore wind turbines. The cost of conducting real-machine grid-connected testing of large-capacity offshore wind turbines is too high, and it is easily affected by environmental factors. Therefore, it is considered to use a ground test platform to test the grid-connected performance of offshore wind power. The ground test platform can simulate different grid conditions, conduct grid-connected tests on large-capacity offshore wind turbines, and verify the safe and stable operation level of wind turbines connected to the grid. How to realize the grid-connected performance test of the ground test platform of wind turbines has become an urgent problem to be solved. Summary of the invention

[0003] The purpose of this application is to provide a ground test platform grid-connected performance test method, device, equipment and medium, which can realize the grid-connected performance test of wind turbines on the ground test platform, with low cost and accurate inspection of the safe and stable operation level of wind turbines connected to the grid.

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

[0005] In a first aspect, the present application provides a method for testing the grid-connected performance of a ground experimental platform, comprising:

[0006] A wind turbine grid-connected model is constructed based on the actual wind turbine on the ground experimental 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] Controlling the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and adverse grid conditions; the grid voltage fault conditions include: grid voltage increase conditions and grid voltage drop conditions; the adverse grid conditions include: voltage deviation conditions, frequency deviation conditions, three-phase voltage unbalance conditions and harmonic voltage conditions;

[0008] Performing a virtual fault performance test on the wind turbine grid-connected model under different grid voltage fault conditions to obtain a virtual fault performance test result; the virtual fault performance test result is used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform;

[0009] The grid-connected adaptability virtual test is performed on the grid-connected model of the wind turbine generator set under different severe grid conditions to obtain the grid-connected adaptability virtual test results; the grid-connected adaptability virtual test results are used to characterize the grid-connected adaptability of the actual wind turbine generator set on the ground experimental platform.

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

[0011] A wind turbine grid-connected model building module is used to build a wind turbine grid-connected model according to the actual wind turbine on the ground experimental 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;

[0012] A grid condition generating module is used to control the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and adverse grid conditions; the grid voltage fault conditions include: grid voltage increase conditions and grid voltage drop conditions; the adverse grid conditions include: voltage deviation conditions, frequency deviation conditions, three-phase voltage unbalance conditions and harmonic voltage conditions;

[0013] A fault performance virtual test module is used to perform 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; the fault performance virtual test result is used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform;

[0014] The grid-connected adaptability virtual test module is used to perform 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; the grid-connected adaptability virtual test result is used to characterize the grid-connected adaptability of the actual wind turbine on the ground experimental platform.

[0015] In a third aspect, the present application provides a computer device, including: 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 any of the above-mentioned ground experimental platform grid-connected performance testing methods.

[0016] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-mentioned ground experimental platform grid-connected performance testing methods.

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

[0018] The present application provides a method, device, equipment and medium for testing the grid-connected performance of a ground test platform. A wind turbine grid-connected model is constructed according to the actual wind turbine on the ground test platform. Different grid voltage fault conditions and severe grid conditions are generated by controlling the virtual grid end in the wind turbine grid-connected model. Virtual testing of the fault performance of the wind turbine grid-connected model under different grid voltage fault conditions and virtual testing of the grid adaptability of the wind turbine grid-connected model under different severe grid conditions are achieved. The present application realizes virtual testing of the grid-connected performance of the wind turbine ground test platform, avoids actual grid-connected testing of large-capacity offshore wind turbines, has low cost, and will not be affected by environmental factors. Therefore, the present application can accurately and cost-effectively test the safe and stable operation level of wind turbine grid-connected operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is an application environment diagram of a method for testing the grid-connected performance of a ground experimental platform in one embodiment of the present application;

[0021] Figure 2 A schematic diagram of a flow chart of a method for testing the grid-connected performance of a ground experimental platform provided in one embodiment of the present application;

[0022] Figure 3 A schematic diagram of the structure of a wind turbine model under test provided in an embodiment of the present application;

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

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

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

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

[0027] Figure 8 A schematic diagram of functional modules of a ground experimental platform grid-connected performance testing device provided in another embodiment of the present application;

[0028] Fig. 9 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0031] The embodiment of the present application digitally models the wind turbine grid-connected system of the ground test platform and conducts virtual tests of the grid-connected performance under different grid conditions. It can not only obtain the dynamic performance simulation results of the wind turbine under different grid conditions, providing a simulation reference for the test of the actual grid-connected system of the ground test platform, but also test whether the grid-connected control system of the ground test platform is effective under different grid conditions, providing a model verification platform for the optimization of the grid-connected control strategy and grid-connected protection system of the ground test platform.

[0032] The ground test platform grid-connected performance test method provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, 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. After the server 104 receives the wind turbine grid-connected model, for the wind turbine grid-connected model, the server 104 controls the virtual grid end in the wind turbine grid-connected model to generate different grid voltage fault conditions and harsh grid conditions; the wind turbine grid-connected model is subjected to a virtual test of fault performance under different grid voltage fault conditions to obtain a virtual test result of fault performance; the wind turbine grid-connected model is subjected to a virtual test of grid adaptability under different harsh grid conditions to obtain a virtual test result of grid adaptability. The server 104 can feed back the obtained virtual test results of fault performance and virtual test results of grid adaptability to the terminal 102. In addition, in some embodiments, the ground test platform grid-connected performance testing method can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly process the wind turbine grid-connected model, or the server 104 can obtain the wind turbine grid-connected model from the data storage system and process the wind turbine grid-connected model.

[0033] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, IoT devices, and portable wearable devices. The IoT devices may be smart speakers, smart TVs, smart air conditioners, smart vehicle-mounted devices, etc. The portable wearable devices may be smart watches, smart bracelets, head-mounted devices, etc. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0034] In an exemplary embodiment, Figure 2 As shown, a method for testing the grid-connected performance of a ground experimental platform is provided. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server 104 in the example is used as an example to illustrate the method, which includes the following steps 201 to 204. Among them:

[0035] Step 201 : constructing a wind turbine grid-connected model according to the actual wind turbine on the ground experimental platform.

[0036] Wherein, the wind turbine grid-connected model includes: a wind turbine end and a virtual grid end; the wind turbine end includes: a model of a wind turbine under test; and the virtual grid end includes: an ideal three-phase voltage source.

[0037] Step 202: Control the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions.

[0038] Among them, the grid voltage fault conditions include: grid voltage rising conditions and grid voltage dropping conditions; the severe grid conditions include: voltage deviation conditions, frequency deviation conditions, three-phase voltage unbalance 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 results are used to characterize the fault ride-through capability of the actual wind turbine generator set on the ground test platform.

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

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

[0043] By implementing the above steps 201 to 204, the grid-connected performance test of the ground test platform of the wind turbine can be realized at low cost, and the safe and stable operation level of the wind turbine grid-connected can be accurately verified.

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

[0045] (1) A wind turbine model to be tested is constructed based on the actual wind turbine on the ground test platform; the wind turbine model to be tested includes: a transmission chain mechanical model and a generator electrical model; the generator electrical model is connected to the functional model interface (FMI) through a zero-order holder; the transmission chain mechanical model is connected to the FMI interface through a delay register. The structure of the wind turbine model to be tested is as follows: Figure 3 shown.

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

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

[0048] This embodiment mainly provides a further detailed introduction to the construction process of the wind turbine model under test.

[0049] Still see Figure 2 According to the mechanism of the actual wind turbine used in the ground experimental platform, the model of the wind turbine to be tested is built. Among them, the electrical part of the wind turbine model to be tested 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 electromagnetic torque parameters, and the transmission chain mechanical model outputs speed and mechanical torque parameters. The two interact with simulation parameters through the FMI interface. The generator electrical model is a doubly fed generator model, which contains the calculation formulas of stator current, rotor current and electromagnetic torque.

[0050] The transmission chain mechanical model of the wind turbine model under test is a two-mass block model of the transmission chain, which includes the calculation formulas for the rotation speed of the wind wheel mass block and the rotation speed of the generator rotor mass block. The mechanical relationship between the two mass blocks is defined by formula (1) to formula (4). The mechanical relationship between the two mass blocks is used 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] Among them, J r Indicates the equivalent inertia of the wind wheel; J g Represents the generator rotor inertia; T m Represents the mechanical torque of the wind wheel, and its value is set according to the virtual test content; T s Indicates the transmission shaft torque; 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 rotor mass block; ω sl Represents the rotational angular velocity of the low-speed shaft of the transmission chain; ω r Indicates the rotational angular velocity of the generator rotor; D r Indicates the damping coefficient of the wind wheel; D g Indicates the damping coefficient of the generator rotor; B s Indicates the equivalent damping coefficient of the transmission shaft; K s represents the equivalent stiffness coefficient of the transmission shaft; N represents the gearbox transmission ratio; ω w represents the variable wind wheel speed; t represents time.

[0055] The generator electrical model of the wind turbine model under test includes: a doubly-fed generator model, whose stator and rotor currents are characterized by a fourth-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 includes: 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). 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 is the voltage component of the stator and rotor in the dq coordinate system; i ds 、i qs 、i dr 、i qr is the current component of the stator and rotor in the dq coordinate system; R s , R rare stator resistance and rotor resistance respectively; ω s is the synchronous angular velocity; p is the number of pole pairs of the generator; L s , L r is the stator and rotor self-inductance; L ls , L lr is the stator and rotor leakage inductance; L m is the mutual inductance coefficient of the generator.

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

[0061]

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

[0063]

[0064] By adjusting the stator current component and the rotor current component, the electromagnetic torque adjustment value is satisfy Then the variable wind wheel speed ω in formula (1) and formula (4) is w , rotor speed ω r The calculation converges. When the wind wheel speed ω w , rotor speed ω r After the calculation converges, the doubly-fed generator model obtains stable stator voltage component, rotor voltage component, stator current component, and rotor current component u ds 、u qs 、u dr 、u qr 、i ds 、i qs 、i dr 、i qr , will u ds 、u qs 、u dr 、u qr 、i ds 、i qs 、i dr 、i qr Substitute into formula (8) to calculate the active power and reactive power of the doubly fed generator model.

[0065] To achieve real-time data interaction between the generator electrical model and the transmission chain mechanical model at different simulation steps, refer to Figure 1 Data processing is performed. First, the initial active power, reactive power, initial stator voltage, and rotor voltage of the generator electrical model are set, and the initial values ​​of the stator and rotor currents are calculated by using formula (8). Then, the electromagnetic torque T is calculated by using formula (7). e The initial value of the electromagnetic torque Te After being processed by the zero-order retainer, a rectangular wave that meets the simulation step length of the transmission chain mechanical model is formed and output to the transmission chain mechanical model with a large step length through the FMI protocol; then, when the transmission chain mechanical model receives the electromagnetic torque T e After the initial data is taken, it is substituted into formula (1)-formula (4) to calculate the corresponding wind wheel speed ω t , Generator mechanical torque T h and the generator rotor speed ω r , the delay register updates the stored mechanical torque T h and the generator rotor speed ω r Simulation data; Finally, the generator electrical model reads the T in the register through the FMI interface h ,ω r Data is substituted into formula (5)-formula (7) to calculate the electromagnetic torque T of the next simulation cycle e Simulation data.

[0066] A 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 It is connected in series with the grid-side equivalent resistance R1 and the grid-side equivalent inductance L1; the wind turbine end is composed of the wind turbine model under test, the filter equivalent resistance R2, and the filter equivalent inductance L2 in series.

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

[0068]

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

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

[0071]

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

[0073] In another exemplary embodiment of the present application, in step 202, the virtual grid terminal of the wind turbine grid-connected model can generate different special grid conditions, including grid voltage failure and severe grid conditions. Grid voltage failure conditions refer to a drop or rise in grid voltage, and severe grid conditions refer to 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] Different types of voltage faults are generated at the virtual grid end of the wind turbine model. The wind turbine model performs different fault ride-through controls according to the type of voltage fault. When simulating different types of grid voltage faults, the voltage change range of the grid connection point is all within Figure 5 In the voltage region shown, the wind turbine model operates continuously without being disconnected from the grid.

[0077] Specifically, by controlling the fault parameters, the virtual grid end in the wind turbine grid-connected model generates different grid voltage fault conditions (such as by setting the fault parameters, the virtual grid end of the wind turbine grid-connected model generates different grid voltage rise conditions and voltage drop conditions), and the wind turbine model under test in the wind turbine grid-connected model responds to the fault type according to the set control parameters, thereby generating a control action corresponding to the grid voltage fault condition. The fault parameters include: the voltage change degree of the virtual grid end, the voltage fault duration and the number of fault phases; the control parameters include: the reactive power support coefficient (low voltage reactive power support coefficient, high voltage reactive power support coefficient), the threshold voltage (low voltage threshold voltage, high voltage threshold voltage) and the current limit value during the grid voltage fault.

[0078] (2) Simulation method of severe power grid conditions.

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

[0080] Furthermore, the voltage deviation condition and frequency deviation condition are generated by setting the amplitude and frequency time variation sequence of the ideal voltage source at the virtual grid end in the wind turbine grid-connected model; the three-phase voltage unbalance condition is generated by introducing the negative sequence voltage component into 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 shown in formula (12) to the grid connection point voltage j to generate.

[0081]

[0082] In the formula, A v is the harmonic amplitude of the vth harmonic; n is the total harmonic number; f g is the power frequency of the power grid; is the harmonic phase angle. The harmonic sequence frequency band is 2.5Hz~1250Hz, covering the harmonics and interharmonics of the power frequency. The injected single harmonic and interharmonic voltage amplitude does not exceed 5%U N , U N is the rated voltage of the grid.

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

[0084] (1) Obtaining the grid connection point voltage amplitude of the wind turbine model under the current grid voltage fault condition.

[0085] (2) Determine whether the voltage amplitude of the grid connection point exceeds a set voltage amplitude range.

[0086] If the voltage amplitude at the grid connection point exceeds the set voltage amplitude range, the wind turbine model under test is not disconnected from the grid, and the fault ride-through protection circuit is activated to limit the converter current and the DC bus voltage to within the set maximum allowable values.

[0087] 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 the grid-connected reactive power are adjusted until the voltage amplitude of the grid-connected point 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.

[0088] Combine the following Figure 6 , the fault ride-through virtual testing process in actual applications is further explained in detail.

[0089] In order to verify the simulation performance of the wind turbine model under test for the high and low voltage ride-through of the actual wind turbine on the ground test platform, three-phase symmetrical and three-phase asymmetrical voltage fault chain tests were carried out under the conditions of the active power output of the wind turbine model under test of 0.2pu and 0.9pu respectively. The chain fault voltage conditions used in the test are: the virtual grid end of the wind turbine grid-connected model first experiences a voltage drop with a drop amplitude of 0.20pu and a duration of 625ms; after an interval of 10ms, the voltage of the virtual grid segment increases with an increase amplitude of 1.30pu and a duration of 500ms. Figure 6 , the fault ride-through control process adopted by the wind turbine model under test is:

[0090] a) The virtual grid end of the wind turbine grid-connected model generates a corresponding grid voltage fault according to the fault parameters. The fault ride-through control program of the wind turbine model under test measures the grid-connected point voltage amplitude, and determines whether the wind turbine module under test is disconnected from the grid based on whether the grid-connected point voltage amplitude is higher than 1.3pu or lower than 0.2pu.

[0091] b) If the judgment result is that the wind turbine model under test continues to be connected to the grid, the fault ride-through protection circuit (including the crowbar circuit and the energy discharge circuit) is activated to limit the converter current and the DC bus voltage to the maximum allowable values.

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

[0093] When the positive sequence voltage component of the grid connection point is lower than the low voltage crossing threshold voltage, the wind turbine model under test supports the virtual grid voltage recovery by injecting reactive current. 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] Where, K1 is the reactive support coefficient of low voltage ride through, and the value of K1 is not less than 1.5 and not more than 3; U T I is the voltage per unit value of the grid connection point; N is the rated current of the wind turbine.

[0096] When the positive sequence voltage component of the grid connection point is higher than the high voltage crossing threshold voltage, the wind turbine model under test supports voltage recovery by actively absorbing reactive current. The dynamic reactive current I T Satisfies formula (14).

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

[0098] Where: K2 is the reactive support coefficient of high voltage ride through, 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 fault ride-through protection circuit is activated and the wind turbine grid-connected model enters the fault ride-through state.

[0100] d) After the grid fault duration ends, the model active power increases at a rate of at least 0.1P per second. n The speed is restored to the output power corresponding to the actual wind conditions, 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 method for estimating the fault ride-through capability of the wind turbine under test is as follows: (1) During the duration of the grid fault, determine whether the wind turbine under test model has been disconnected from the grid based on the grid connection point voltage. If the grid connection point voltage is zero, it means that the wind turbine under test model cannot maintain the grid connection state when the grid fault continues, the model virtual test fails, and the grid connection relay capacity of the wind turbine under test may be insufficient. (2) If the wind turbine under test model can maintain fault grid connection operation, then check whether the converter current and DC bus voltage of the model exceed the maximum allowable value. If they exceed the maximum allowable value, it means that the resistance of the crowbar circuit and the energy dissipation circuit of the wind turbine under test may be too small. (3) During the measurement of the grid fault, whether the reactive power injected or absorbed by the wind turbine under test model to the virtual grid end of the grid connection model meets the standard requirements. If not, the reactive power control program needs to be optimized. (4) Measure whether the fluctuation amplitude of the active power during the voltage fault meets the limit value, and observe whether the recovery speed of the active power after the low voltage ride-through ends reaches 0.1P n / s. If it does not meet the requirements, the active power control program needs to be optimized.

[0102] In another exemplary embodiment of the present application, in step 204, before the actual wind turbine grid-connected adaptability test is performed on the ground test platform, a virtual test of grid-connected adaptability under severe grid conditions is first performed in the wind turbine grid-connected model. Different disturbance conditions are set in the virtual grid terminal of the grid-connected model, and the grid-connected electrical quantity simulation curves of the wind turbine model under various grid disturbance conditions are simulated and recorded, and the grid-connected performance of the wind turbine on the actual ground test platform is estimated based on the simulation data. The tested grid-connected performance is: voltage deviation adaptability, frequency deviation adaptability, grid background harmonic adaptability, and three-phase voltage imbalance adaptability.

[0103] Step 204 specifically includes:

[0104] Under the voltage deviation condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first voltage deviation adaptability test result; if the wind turbine model under test is off-grid, record the second voltage deviation adaptability test result; the first voltage deviation adaptability test result includes: the waveform of the active power 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 waveform of the electrical quantity that triggers the off-grid protection.

[0105] Under the frequency deviation condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first frequency deviation adaptability test result; if the wind turbine model under test is off-grid, record the second frequency deviation adaptability test result; the first frequency deviation adaptability test result includes: the waveform of the grid-connected current frequency 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 waveform of the electrical quantity that triggers the off-grid protection.

[0106] Under the three-phase voltage imbalance condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first voltage imbalance adaptability test result; if the wind turbine model under test is off-grid, record the second voltage imbalance adaptability test result; the first voltage imbalance adaptability test result includes: the negative sequence imbalance of the grid-connected point voltage and the negative sequence imbalance of the grid-connected point current in the voltage imbalance simulation test; 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 that triggers the off-grid protection.

[0107] Under the harmonic voltage condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first harmonic voltage adaptability test result; if the wind turbine model under test is off-grid, record the second harmonic voltage adaptability test result; the first harmonic voltage adaptability test result includes: the total harmonic distortion rate of the grid-connected point voltage and the total harmonic distortion rate of the grid-connected point current in the harmonic voltage simulation test; the second harmonic voltage adaptability test result includes: the duration of the harmonic voltage simulation test, the off-grid time, and the electrical quantity waveform that triggers the off-grid protection.

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

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

[0110] 1. Voltage deviation adaptability.

[0111] The mechanical torque T of the wind turbine model to be tested m Set it to 0.2pu and use the following steps to perform simulation tests.

[0112] a) Set the initial grid voltage to the rated value, and gradually reduce the voltage amplitude by 1% of the rated voltage at the rated frequency, with the voltage rising by 0.01pu every 20s. After the voltage rises to 1.10pu, keep the voltage value unchanged for 10min. Test whether the wind turbine model under test can be connected to the grid normally. If it can operate normally, measure and record the waveform of the active power in the simulation test; if the wind turbine model under test is disconnected from the grid, record the duration of the simulation test, the time of disconnection, and the waveform of the electrical quantity that triggers the disconnection protection.

[0113] b) Set the initial grid voltage to the rated value, and gradually reduce the voltage amplitude by 1% of the rated voltage at the rated frequency, with the voltage decreasing by 0.01 pu every 20 seconds. After the voltage drops to 0.90 pu, keep the voltage value unchanged for 10 minutes. Test whether the wind turbine model under test can be connected to the grid normally. If it can operate normally, measure and record the waveform of the active power in the simulation test; if the wind turbine model under test is disconnected from the grid, record the duration of the simulation test, the time of disconnection, and the waveform of the electrical quantity that triggers the disconnection protection.

[0114] 2. Frequency deviation adaptability.

[0115] The mechanical torque T of the wind turbine model wind rotorm Set it to 0.2pu and use the following steps to perform simulation tests.

[0116] a) Set the voltage frequency of the virtual grid end of the grid-connected model to 50HZ, and gradually increase the voltage frequency by 0.1Hz at the rated voltage, increasing by 0.1Hz every 20s. Increase to the maximum frequency allowed for the wind turbine under test, and then keep the maximum frequency unchanged for 1min. Test whether the wind turbine model under test can be connected to the grid normally. If it can operate normally, measure and record the waveform of the grid-connected current frequency in the simulation test; if the wind turbine model under test is disconnected from the grid, record the duration of the simulation test, the time of disconnection, and the waveform of the electrical quantity that triggers the disconnection protection.

[0117] b) Set the voltage frequency of the virtual grid end of the grid-connected model to 50HZ, and gradually reduce the voltage frequency by 0.1Hz at the rated voltage, reducing it by 0.1Hz every 20s. Reduce it to the minimum frequency allowed for the wind turbine under test, and then keep the minimum frequency unchanged for 1min. Test whether the wind turbine model under test can be connected to the grid normally. If it can operate normally, measure and record the waveform of the grid-connected current frequency in the simulation test; if the wind turbine model under test is disconnected from the grid, record the duration of the simulation test, the time of disconnection, and the waveform of the electrical quantity that triggers the disconnection protection.

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

[0119] The mechanical torque T of the wind turbine model to be tested m Set to 0.5pu, let the wind turbine model under test run normally at rated voltage and rated frequency, then add background harmonics to the virtual grid end of the grid-connected model for a duration of 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 run normally in grid connection. If it can run normally, measure and record the total harmonic distortion rate of the voltage and current at the grid connection point in the simulation test; if the wind turbine model under test is off-grid, record the duration of the simulation test, the off-grid time, and the electrical quantity waveform that triggers the off-grid protection.

[0120] 4. Adaptability to three-phase voltage imbalance.

[0121] The mechanical torque T of the wind turbine model to be tested m Set it to 0.5pu and use the following steps to perform simulation tests.

[0122] a) Allow the wind turbine model under test to operate normally at rated voltage and rated frequency, and then adjust the voltage amplitude of each phase so that the output voltage of the virtual grid end of the grid-connected model is 2.0%, and the duration is 30 minutes. Test whether the wind turbine model under test can be connected to the grid normally. If it can operate normally, measure and record the negative sequence imbalance of the voltage and current at the grid connection point in the simulation test; if the wind turbine model under test is disconnected from the grid, record the duration of the simulation test, the time of disconnection, and the waveform of the electrical quantity that triggers the disconnection protection.

[0123] b) Allow the wind turbine model under test to operate normally at rated voltage and rated frequency, and then adjust the voltage amplitude of each phase so that the output voltage of the virtual grid end of the grid-connected model is 4.0%, and the duration is 1 minute. Test whether the wind turbine model under test can be connected to the grid normally. If it can operate normally, measure and record the negative sequence imbalance of the voltage and current at the grid connection point in the simulation test; if the wind turbine model under test is disconnected from the grid, record the duration of the simulation test, the time of disconnection, and the waveform of the electrical quantity that triggers the disconnection protection.

[0124] The above steps 203 and 204 of this embodiment implement a virtual test of grid-connected performance. Figure 7 As shown in the figure, according to the grid-connected safety verification method of the ground test platform, the simulation system conducts a virtual test of the grid-connected performance of the wind turbine model used in the ground test. The test content is the fault ride-through capability and the grid-connected adaptability under the condition of a harsh power grid. The wind turbine model used in the virtual test is built according to the wind turbine used in the ground test platform, which can achieve a simulation accuracy of more than 85%. The simulation system refers to the rated safety parameter thresholds of each electrical component of the platform, and feeds back to the ground test platform the operating conditions where the model electrical components exceed the safety threshold in the virtual test, so as to estimate the fault ride-through capability and grid-connected adaptability of the wind turbine on the ground test platform.

[0125] The embodiment of the present application realizes a virtual test method for the grid-connected performance of a ground test platform based on a wind turbine grid-connected model. The wind turbine grid-connected model includes a model of a wind turbine to be tested, an ideal three-phase voltage source, a network-tested equivalent resistance element, a network-tested equivalent inductance element, a filter equivalent resistance element, and a filter equivalent inductance element. The model of the wind turbine to be tested is built according to the wind turbine used in the ground test platform. The wind turbine grid-connected model can set different grid conditions according to the grid-connected performance test content to simulate the grid-connected characteristics, and estimate the grid-connected capability of the wind turbine used in the ground test platform based on the simulation results, providing data reference for the grid-connected performance analysis of the wind turbine on the ground test platform during actual operation.

[0126] Specifically, a modeling method for the wind turbine model under test on the ground test platform was designed to achieve data interaction between models with different simulation step sizes. The simulation results can simulate the coupling relationship between mechanical quantities and electrical quantities. In order to solve the problem of large differences in simulation step sizes between the mechanical model and the electrical model of the wind turbine under test, a delay register and a zero-order sampler are used to process the interactive data between the two to achieve real-time data interaction between them. A virtual test method for grid-connected performance based on the wind turbine grid-connected model was also designed. Different wind turbine grid-connected model voltage faults and adverse grid conditions were set according to the virtual test content, and low voltage ride-through capability and grid-connected adaptability simulation virtual tests of the wind turbine model under test were conducted to provide grid-connected performance estimates before actual testing 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 implementing the ground test platform grid-connected performance test method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more ground test platform grid-connected performance test device embodiments provided below can refer to the limitations of the ground test platform grid-connected performance test method above, and will not be repeated here.

[0128] In an exemplary embodiment, Figure 8 As shown, a ground experimental platform grid-connected performance test device is provided, comprising:

[0129] The wind turbine grid-connected model construction module 801 is used to construct a wind turbine grid-connected model based on the actual wind turbine on the ground experimental 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.

[0130] The grid condition generating module 802 is used to control the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions; the grid voltage fault conditions include: grid voltage increase 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.

[0131] The fault performance virtual test module 803 is used to perform 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; the fault performance virtual test result is used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform.

[0132] The grid-connected adaptability virtual test module 804 is used to perform 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; the grid-connected adaptability virtual test result is used to characterize the grid-connected adaptability of the actual wind turbine on the ground test platform.

[0133] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig. 9 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as 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 used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store a wind turbine grid-connected model. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a ground experimental platform grid-connected performance test method is implemented.

[0134] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may 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 further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0136] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0137] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0138] Those of ordinary skill 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, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the 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. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0139] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, etc., but is not limited thereto.

[0140] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0141] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for testing the grid-connected performance of a ground experimental platform, characterized in that: The ground experimental platform grid-connected performance test method comprises: A wind turbine grid-connected model is constructed based on the actual wind turbine on the ground experimental 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; Controlling the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and adverse grid conditions; the grid voltage fault conditions include: grid voltage increase conditions and grid voltage drop conditions; the adverse grid conditions include: voltage deviation conditions, frequency deviation conditions, three-phase voltage unbalance conditions and harmonic voltage conditions; Performing a virtual fault performance test on the wind turbine grid-connected model under different grid voltage fault conditions to obtain a virtual fault performance test result; the virtual fault performance test result is used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform; The grid-connected adaptability virtual test is performed on the grid-connected model of the wind turbine generator set under different severe grid conditions to obtain the grid-connected adaptability virtual test results; the grid-connected adaptability virtual test results are used to characterize the grid-connected adaptability of the actual wind turbine generator set on the ground experimental platform.

2. The method for testing the grid-connected performance of a ground experimental platform according to claim 1, characterized in that: The wind turbine grid-connected model is constructed based on the actual wind turbine on the ground experimental platform, including: A model of the wind turbine to be tested is constructed according to the actual wind turbine on the ground test platform; the model of the wind turbine to be tested includes: a transmission chain mechanical model and a generator electrical model; the generator electrical model is connected to the FMI interface through a zero-order holder; the transmission chain mechanical model is connected to the FMI interface through a delay register; Connecting the wind turbine model to be measured, the filter equivalent resistor and the filter equivalent inductor in sequence to form the wind turbine end; The ideal three-phase voltage source, the grid-side equivalent resistance and the grid-side equivalent inductance are connected in sequence to form the virtual grid terminal; The grid-side equivalent inductance of the virtual grid end is connected to a common connection point through a transformer, and the filter equivalent inductance in the wind turbine generator set end is connected to the common connection point to obtain a grid-connected model of the wind turbine generator set.

3. The method for testing the grid-connected performance of a ground experimental platform according to claim 1, characterized in that: Controlling the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and severe grid conditions, specifically including: By controlling the fault parameters, different grid voltage fault conditions are generated at the virtual grid end in the wind turbine grid-connected model, and the wind turbine model under test in the wind turbine grid-connected model responds to the fault type according to the control parameters, thereby generating a control action corresponding to the grid voltage fault condition; the fault parameters include: the voltage change degree, voltage fault duration and fault phase number of the virtual grid end; the control parameters include: the cross-reactive support coefficient, the cross-threshold voltage and the current limit value when the grid voltage fails; A voltage deviation condition is generated by setting an amplitude time variation sequence for an ideal voltage source at a virtual grid end in the wind turbine grid-connected model; A frequency deviation operating condition is generated by setting a frequency time variation sequence for an ideal voltage source at a virtual grid end in the wind turbine grid-connected model; By introducing a negative sequence voltage component into the ideal voltage source at the virtual grid end in the wind turbine grid-connected model, a three-phase voltage unbalanced condition is generated; A harmonic voltage operating condition is generated by adding a harmonic sequence to the grid connection point voltage in the wind turbine grid connection model.

4. The method for testing the grid-connected performance of a ground experimental platform according to claim 1, characterized in that: The wind turbine grid-connected model is subjected to a fault performance virtual test under different grid voltage fault conditions to obtain a fault performance virtual test result, specifically including: Obtaining the grid connection point voltage amplitude of the wind turbine model under the current grid voltage fault condition; Determining whether the voltage amplitude of the grid connection point exceeds a set voltage amplitude range; If the voltage amplitude of the grid connection point exceeds the set voltage amplitude range, the wind turbine model under test is not disconnected from the grid, and the fault ride-through protection circuit is put into operation to limit the converter current and the DC bus voltage to within the set maximum allowable values; 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 the grid-connected reactive power are adjusted until the voltage amplitude of the grid-connected point 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 for testing the grid-connected performance of a ground experimental platform according to claim 1, characterized in that: The grid-connected adaptability virtual test is performed on the wind turbine grid-connected model under different severe grid conditions to obtain the grid-connected adaptability virtual test results, which specifically include: Under the voltage deviation condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first voltage deviation adaptability test result; if the wind turbine model under test is off-grid, record the second voltage deviation adaptability test result; the first voltage deviation adaptability test result includes: the waveform of active power 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 waveform of the electrical quantity that triggers the off-grid protection; Under the frequency deviation condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first frequency deviation adaptability test result; if the wind turbine model under test is off-grid, record the second frequency deviation adaptability test result; the first frequency deviation adaptability test result includes: the waveform of the grid-connected current frequency 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 waveform of the electrical quantity that triggers the off-grid protection; Under the three-phase voltage imbalance condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first voltage imbalance adaptability test result; if the wind turbine model under test is off-grid, record the second voltage imbalance adaptability test result; 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; 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 that triggers the off-grid protection; Under the harmonic voltage condition, determine whether the wind turbine model under test is off-grid. If the wind turbine model under test is not off-grid, record the first harmonic voltage adaptability test result; if the wind turbine model under test is off-grid, record the second harmonic voltage adaptability test result; the first harmonic voltage adaptability test result includes: the total harmonic distortion rate of the grid-connected point voltage and the total harmonic distortion rate of the grid-connected point current in the harmonic voltage simulation test; the second harmonic voltage adaptability test result includes: the duration of the harmonic voltage simulation test, the off-grid time, and the electrical quantity waveform that triggers the off-grid protection; The grid-connected adaptability virtual test results include: a first voltage deviation adaptability test result, a second voltage deviation adaptability test result, a first frequency deviation adaptability test result, a second frequency deviation adaptability test result, a first voltage imbalance adaptability test result, a second voltage imbalance adaptability test result, a first harmonic voltage adaptability test result and a second harmonic voltage adaptability test result.

6. The method for testing the grid-connected performance of a ground experimental platform according to claim 2, characterized in that: The expression of the transmission chain mechanical model is: Among them, J r Indicates the equivalent inertia of the wind wheel; J g Represents the generator rotor inertia; T m Represents the mechanical torque of the wind wheel; T s Indicates the transmission shaft torque; 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 rotor mass block; ω sl Represents the rotational angular velocity of the low-speed shaft of the transmission chain; ω r Indicates the rotational angular velocity of the generator rotor; D r Indicates the damping coefficient of the wind wheel; D g Indicates the damping coefficient of the generator rotor; B s Indicates the equivalent damping coefficient of the transmission shaft; K s represents the equivalent stiffness coefficient of the transmission shaft; N represents the gearbox transmission ratio; ω w represents the variable wind wheel speed; t represents time.

7. The method for testing the grid-connected performance of a ground experimental platform according to claim 2, characterized in that: 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-connected performance test device, characterized in that: The ground experimental platform grid-connected performance test device comprises: A wind turbine grid-connected model building module is used to build a wind turbine grid-connected model according to the actual wind turbine on the ground experimental 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; A grid condition generating module is used to control the virtual grid terminal in the wind turbine grid-connected model to generate different grid voltage fault conditions and adverse grid conditions; the grid voltage fault conditions include: grid voltage increase conditions and grid voltage drop conditions; the adverse grid conditions include: voltage deviation conditions, frequency deviation conditions, three-phase voltage unbalance conditions and harmonic voltage conditions; A fault performance virtual test module is used to perform 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; the fault performance virtual test result is used to characterize the fault ride-through capability of the actual wind turbine on the ground test platform; The grid-connected adaptability virtual test module is used to perform 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; the grid-connected adaptability virtual test result is used to characterize the grid-connected adaptability of the actual wind turbine on the ground experimental 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 experimental platform grid-connected performance testing method described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the ground experimental platform grid-connected performance testing method described in any one of claims 1-7 is implemented.

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