A method and device for testing characteristics of a grid-connected new energy unit

Abstract

The present invention provides a method and device for testing the characteristics of a grid-forming new energy unit, and relates to the field of testing technology. The method comprises: switching the inverter unit control mode to VF control, calculating the system impedance parameters corresponding to each grid strength; determining the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power; performing a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and recording the grid strength adaptability test result data. The device executes the above method. The method and device provided by the embodiment of the present invention can efficiently and accurately perform a grid-forming new energy unit characteristic test.

Description

Technical Field

[0001] The present invention relates to the field of testing technology, and in particular to a method and device for testing characteristics of a grid-connected new energy generator set. Background Art

[0002] In recent years, the new energy industry has developed rapidly, and the installed capacity of wind power and photovoltaic power has continued to grow. The mainstream new energy units adopt a grid-following control method in which the phase-locked loop passively follows the grid voltage, and do not have the ability to actively support frequency and voltage. The access of large-scale new energy sources brings potential risks to the safe and stable operation of the power grid. In this context, grid-building new energy units with the ability to independently establish voltage and frequency have gradually become a research hotspot and have broad application prospects.

[0003] The characteristics of grid-building units are significantly different from those of grid-following units in terms of self-built voltage capability, frequency / voltage active support capability, and grid strength adaptability. However, there is currently no standardized testing method for the grid-connected characteristics of grid-building units. Summary of the invention

[0004] In view of the problems in the prior art, an embodiment of the present invention provides a method and device for testing characteristics of a grid-connected new energy unit, which can at least partially solve the problems existing in the prior art.

[0005] On the one hand, the present invention proposes a method for testing the characteristics of a grid-connected new energy unit, including a method for testing the adaptability of a grid strength, specifically comprising:

[0006] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0007] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0008] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0009] Among them, the grid-connected new energy unit characteristic test method includes a transient overvoltage test method, specifically including:

[0010] Switch the inverter unit control mode to VF control, and calculate the corresponding system impedance parameters and short-circuit impedance parameters according to the transient overvoltage condition to be simulated;

[0011] Determine the voltage amplitude of the second control test port and the voltage phase of the second control test port according to the infinite grid phase voltage, the phase voltage on the high-voltage side of the unit box transformer, the phase active power of the new energy unit, the phase reactive power of the new energy unit, the phase active power and phase reactive power of the grid flowing to the short-circuit branch, the system impedance parameters and the short-circuit impedance parameters;

[0012] A transient overvoltage test is performed according to the voltage amplitude of the second control test port and the voltage phase of the second control test port, and transient overvoltage test result data is recorded.

[0013] The grid-connected new energy unit characteristic test method includes an isolated grid operation test method, which specifically includes:

[0014] Switch the inverter unit control mode to PQ control, and calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage;

[0015] Perform an isolated grid operation test according to the active load power setting value and record the isolated grid operation test result data.

[0016] The grid-connected new energy unit characteristic test method includes a black start test method, which specifically includes:

[0017] Switch the inverter unit control mode to PQ control, calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage, and set the reactive load power setting value to zero;

[0018] Perform a black start test according to the active load power setting value and record the black start test result data.

[0019] The grid-type new energy unit characteristic test method includes a frequency active support test method, which specifically includes:

[0020] Switch the inverter unit control mode to VF control, and use the voltage amplitude generated by the inverter unit VF control system as the voltage amplitude of the third control test port;

[0021] Determine the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system;

[0022] Perform an active frequency support test based on the voltage amplitude of the third control test port, the voltage phase of the third control test port, the load frequency adjustment coefficient of the scenario to be simulated, the primary frequency regulation equivalent adjustment coefficient, the first-order delay time constant and the disturbance power, and record the active frequency support test result data.

[0023] The step of determining the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system includes:

[0024] The equivalent frequency model is connected in series to the voltage phase generation branch of the inverter unit VF control system;

[0025] Correspondingly, the sum of the frequency variation output by the equivalent frequency model and the system power frequency is calculated, and the sum result is integrated to obtain the voltage phase of the third control test port.

[0026] On the one hand, the present invention proposes a grid-type new energy unit characteristic testing device including a grid strength adaptability testing device, specifically comprising:

[0027] A calculation unit, used to switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0028] A determination unit, used to determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0029] The test unit is used to perform a grid strength adaptability test according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and record grid strength adaptability test result data.

[0030] In another aspect, an embodiment of the present invention 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 implements the following method when executing the computer program:

[0031] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0032] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0033] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0034] An embodiment of the present invention provides a computer-readable storage medium, including:

[0035] The computer readable storage medium stores a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0036] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0037] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0038] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0039] The embodiment of the present invention further provides a computer program product, the computer program product comprising a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0040] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0041] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0042] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0043] The grid-type new energy unit characteristic testing method and device provided in the embodiment of the present invention include switching the inverter unit control mode to VF control, calculating the system impedance parameters corresponding to each grid strength respectively; determining the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power; performing a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and recording the grid strength adaptability test result data, so as to efficiently and accurately perform a grid-type new energy unit characteristic test. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0045] Figure 1 It is a flow chart of a method for testing characteristics of a grid-connected new energy generator set provided in one embodiment of the present invention.

[0046] Figure 2 It is a structural diagram of a grid-type new energy unit characteristic testing device provided in an embodiment of the present invention.

[0047] Figure 3 It is a control block diagram of a rectifier unit of a test device provided in an embodiment of the present invention.

[0048] Figure 4 It is a control block diagram of the inverter unit PQ of the test device provided by an embodiment of the present invention.

[0049] Figure 5 It is a control block diagram of the inverter unit VF of the test device provided by an embodiment of the present invention.

[0050] Figure 6 It is a schematic diagram of connecting a new energy generator set to a power grid according to an embodiment of the present invention.

[0051] Figure 7 It is a schematic diagram of voltage drop provided by an embodiment of the present invention.

[0052] Figure 8 This is a test wiring diagram provided by an embodiment of the present invention.

[0053] Fig. 9 It is a transient overvoltage simulation principle diagram provided by an embodiment of the present invention.

[0054] Fig.10 It is a schematic diagram illustrating a VF / PQ control switching strategy provided by an embodiment of the present invention.

[0055] Fig.11 It is a schematic diagram illustrating a simplified equivalent frequency model of a system provided in an embodiment of the present invention.

[0056] FIG. 12( a ) is a diagram showing the positive-sequence voltage simulation results of the grid strength adaptability test scenario 1 provided in an embodiment of the present invention.

[0057] FIG12( b ) is a diagram showing the positive sequence voltage simulation results of the grid strength adaptability test scenario 2 provided in an embodiment of the present invention.

[0058] FIG. 13( a ) is a diagram showing the active power simulation results of the grid strength adaptability test scenario 1 provided in an embodiment of the present invention.

[0059] FIG13( b ) is a diagram of active power simulation results of the grid strength adaptability test scenario 2 provided in an embodiment of the present invention.

[0060] FIG. 14( a ) is a diagram showing reactive power simulation results of a grid strength adaptability test scenario 1 provided in an embodiment of the present invention.

[0061] FIG14( b ) is a diagram showing reactive power simulation results of the second grid strength adaptability test scenario provided in an embodiment of the present invention.

[0062] FIG. 15( a ) is a diagram showing the positive-sequence voltage simulation results of transient overvoltage response test scenario 1 provided in an embodiment of the present invention.

[0063] FIG. 15( b ) is a diagram showing the positive-sequence voltage simulation results of transient overvoltage response test scenario 2 provided in an embodiment of the present invention.

[0064] FIG. 16( a ) is a diagram showing the active power simulation results of transient overvoltage response test scenario 1 provided in an embodiment of the present invention.

[0065] FIG. 16( b ) is a diagram showing the active power simulation results of transient overvoltage response test scenario 2 provided in an embodiment of the present invention.

[0066] FIG. 17( a ) is a diagram showing reactive power simulation results of transient overvoltage response test scenario 1 provided in an embodiment of the present invention.

[0067] FIG. 17( b ) is a diagram showing reactive power simulation results of transient overvoltage response test scenario 2 provided in an embodiment of the present invention.

[0068] FIG. 18( a ) is a diagram showing the active power simulation results of the self-built voltage test scenario 1 provided in an embodiment of the present invention.

[0069] FIG18( b ) is a diagram showing the active power simulation results of the self-built voltage test scenario 2 provided in an embodiment of the present invention.

[0070] FIG. 19( a ) is a diagram showing reactive power simulation results of a self-built voltage test scenario 1 provided in an embodiment of the present invention.

[0071] FIG. 19( b ) is a diagram showing reactive power simulation results of the second self-built voltage test scenario provided in an embodiment of the present invention.

[0072] FIG. 20( a ) is a diagram showing the simulation results of the A-phase current of the self-built voltage test scenario 1 provided in an embodiment of the present invention.

[0073] FIG. 20( b ) is a diagram showing the simulation results of the A-phase current of the second self-built voltage test scenario provided in an embodiment of the present invention.

[0074] FIG. 21( a ) is a diagram showing system frequency simulation results of a frequency active support test provided in an embodiment of the present invention.

[0075] Figure 21(b) is a diagram of the active power simulation results of the frequency active support test provided in an embodiment of the present invention.

[0076] Fig. 22 It is a structural schematic diagram of a grid-type new energy unit characteristic testing device provided in one embodiment of the present invention.

[0077] Fig.23 A schematic diagram of the physical structure of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0078] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily.

[0079] Figure 1 : is a flow chart of a method for testing characteristics of a grid-connected new energy generator set provided by an embodiment of the present invention, such as Figure 1 As shown, the grid-connected new energy unit characteristic testing method provided by the embodiment of the present invention includes a grid strength adaptability testing method, which specifically includes:

[0080] Step S1: Switch the inverter unit control mode to VF control, and calculate the system impedance parameters corresponding to each grid strength.

[0081] Step S2: Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit transformer high-voltage side voltage, unit transformer high-voltage side active power and unit transformer high-voltage side reactive power.

[0082] Step S3: Perform a grid strength adaptability test according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and record grid strength adaptability test result data.

[0083] In the above step S1, the device switches the inverter unit control mode to VF control and calculates the system impedance parameters corresponding to the strength of each power grid. The device can be a computer device that executes the method. The acquisition, storage, use, and processing of data in the technical solution of this application are in compliance with relevant regulations.

[0084] The structure of the grid-type new energy unit characteristic test device is as follows: Figure 2 As shown, it includes a step-down transformer, a rectifier unit, an inverter unit, a step-up transformer and a filter capacitor.

[0085] The control block diagram of the rectifier unit is as follows: Figure 3 As shown, the control goal is to achieve the converter running at unity power factor while maintaining the DC side voltage stable to the rated value.

[0086] The inverter unit control mode includes PQ control, such as Figure 4 As shown; the inverter unit control mode includes VF control, such as Figure 5 shown.

[0087] The grid strength adaptability test function is described as follows:

[0088] When the device conducts grid strength adaptability test, its inverter unit control adopts VF control, that is, controls the amplitude and frequency (or phase angle) of the port voltage to reach the set value. Calculate the change of the port voltage when the new energy unit is connected to the grid with different strengths, and then obtain the voltage amplitude and phase angle setting values ​​used to simulate different grid strengths.

[0089] like Figure 6 As shown, Figure 6 Where U1 is the grid voltage, with a per-unit value of 1∠0°, U2 is the voltage on the high-voltage side of the generator box transformer (U1 and U2 are both phase voltages), Rs and Xs are the system resistance and system reactance, PN and QN are the active power and reactive power on the high-voltage side of the generator box transformer, and P2 and Q2 are the active power and reactive power on the grid side. The grid strength is defined by the system short-circuit ratio (SCR), and the system impedance can be calculated based on the short-circuit ratio. The calculation formula is:

[0090]

[0091] In the formula, Z S is the system impedance, SCR is the system short-circuit ratio; Sn is the rated power of the wind turbine generator set, and U is the rated voltage of the test equipment. The ratio of system resistance and system reactance is designed according to the test requirements and can be selected as 1:10.

[0092] When the system impedance parameters are determined, the voltage U at the port of the test device is controlled. D The amplitude V D and phase θ D By making it the same as U2, the simulation of the unit under test being connected to a power grid of this strength can be realized.

[0093] According to the power system flow calculation principle, the horizontal and vertical components of the voltage drop between U1 and U2 are as follows: Figure 7 As shown in formula (2), δU2 and ΔU2 are the horizontal and vertical components of the voltage drop between U1 and U2, respectively. is the angle between U2 and I2, and θ is the angle between U1 and U2.

[0094]

[0095] The geometric relationship of voltage drop is shown in equation (3):

[0096]

[0097] Substituting P2 = -PN, Q2 = -QN into equation (3), considering that Rs is much smaller than Xs in the case of long-distance transmission, the Rs term is ignored in the solution process, and the amplitude V2 and phase θ2 of U2 are obtained as follows:

[0098]

[0099] The result of equation (4) is used as the control setting of the device inverter unit, that is, V D =V2,θ D =θ can obtain the device outlet voltage when the system impedance is Rs and Xs, thus realizing the simulation of the power grid strength.

[0100] like Figure 8 As shown, the grid strength adaptability test is described as follows:

[0101] Step 1: Confirm that the fan is in shutdown state and the bypass switch is disconnected;

[0102] Step 2: Close the inlet and outlet switches of the device;

[0103] Step 3: Turn on the device and set the inverter unit control mode to VF control;

[0104] Step 4: Calculate the corresponding system impedance parameters under the conditions of strong power grid (SCR=10), weak power grid (SCR=3), and extremely weak power grid (SCR=1.5);

[0105] Step 5: Start the unit and test it for 10 minutes in the low power range (0.1× rated active power of the unit ≤ unit active power ≤ 0.3× rated active power of the unit) and high power range (unit active power>0.9× rated active power of the unit) under strong grid, weak grid and extremely weak grid conditions. D and θ D The given values ​​of are set according to the system impedance parameters according to formula (4);

[0106] Step 6: Record the test data.

[0107] The system impedance parameters corresponding to each power grid strength are calculated, and the system impedance parameters Rs and Xs can be reversely calculated by formula (1).

[0108] In the above step S2, the device determines the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power within each preset power interval. Each preset power interval range includes the above low-power interval and the above high-power interval. That is, the first control test port voltage amplitude and the first control test port voltage phase are calculated according to formula (4).

[0109] In the above step S3, the device performs a grid strength adaptability test according to the voltage amplitude and the voltage phase of the first control test port, and records the grid strength adaptability test result data. Please refer to the description of the above step 5.

[0110] The grid-connected new energy unit characteristic test method includes a transient overvoltage test method, specifically including:

[0111] Switch the inverter unit control mode to VF control, and calculate the corresponding system impedance parameters and short-circuit impedance parameters according to the transient overvoltage condition to be simulated; the system transient overvoltage test function requirements for grid-type units are as follows:

[0112] The simulation of the DC near-zone continuous commutation failure and AC power grid single-phase transient voltage fault under different system short-circuit ratios can be achieved. The simulation of these conditions can be achieved by grounding the machine end through the short-circuit impedance. In order to simulate the single-phase, two-phase or three-phase faults in the power grid, the three-phase voltages at the device port are controlled separately. During the analysis, the A phase voltage in the system is taken as the research object, and the principles of the B and C phases are the same. Fig. 9 As shown, U1A and U2A are the A-phase voltages on the high-voltage side of the infinite power grid and the unit box transformer, respectively; PNA, QNA, P2A, Q2A are the A-phase active power and reactive power flowing from the new energy unit and the power grid to the short-circuit branch, respectively; Xs and Rs are the system reactance and system resistance, respectively; Xsc and Rsc are the A-phase short-circuit reactance and short-circuit resistance, respectively.

[0113] Similar to the grid strength adaptability test, the relationship between the transverse component and the longitudinal component between U2A and U1A is shown in equation (5), where θ A is the included angle between U1A and U2A.

[0114]

[0115] Considering the active and reactive power of the short-circuit branch, the calculation formulas of P2A and Q2A are shown in formula (6):

[0116]

[0117] Solve them together, ignoring Rs and Rsc, and get U2A, θ A The solution is as follows:

[0118]

[0119] Let the voltage U at the A phase port of the control test device be DA The amplitude V DA =U 2A , phase θ DA =θ A , so that it exhibits corresponding characteristics during transient overvoltage testing.

[0120] The transient overvoltage test is described as follows:

[0121] Step 1: Confirm that the fan is in shutdown state and the bypass switch is disconnected;

[0122] Step 2: Close the inlet and outlet switches of the device;

[0123] Step 3: Turn on the device and set the inverter unit control mode to VF control;

[0124] Step 4: Determine the transient overvoltage condition to be simulated and calculate the corresponding system impedance and short-circuit impedance parameters;

[0125] Step 5: Start the unit and set VD and θ D The given value of is set according to formula (7) and the test is carried out;

[0126] Step 6: Record the test data.

[0127] The transient overvoltage conditions to be simulated are the continuous commutation failure of the DC near area and the single-phase transient voltage fault of the AC power grid under the above-mentioned different system short-circuit ratios.

[0128] The corresponding system impedance parameters and short-circuit impedance parameters are calculated according to the transient overvoltage condition to be simulated, which can be achieved by using mature technologies in the field.

[0129] According to the infinite grid phase voltage, the high-voltage side phase voltage of the unit transformer, the phase active power of the new energy unit, the phase reactive power of the new energy unit, the phase active power and phase reactive power of the grid flowing to the short-circuit branch, the system impedance parameters and the short-circuit impedance parameters, the voltage amplitude of the second control test port and the voltage phase of the second control test port are determined; the voltage amplitude of the second control test port and the voltage phase of the second control test port can be calculated according to the above formula (7).

[0130] A transient overvoltage test is performed according to the voltage amplitude of the second control test port and the voltage phase of the second control test port, and transient overvoltage test result data is recorded.

[0131] The grid-connected new energy unit characteristic test method includes an isolated grid operation test method, specifically including:

[0132] Switch the inverter unit control mode to PQ control, and calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage; when the device conducts the self-built pressure test of the grid-type unit, it is connected to the unit under test as an adjustable load, and its inverter unit adopts PQ control. When the angle σ of the port current leading the port voltage is -90° to 90° through PQ control, the device presents a load characteristic, where when σ=0, the device presents a positive resistance characteristic; when σ is 0° to 90°, the device is a capacitive load, absorbing active power and capacitive reactive power; when σ is -90° to 0°, the device is an inductive load, absorbing active power and emitting capacitive reactive power.

[0133] During the self-built pressure test, the device needs to achieve smooth switching between power supply state and load state, that is, smooth switching between VF control and PQ control. Figure 4 and Figure 5 It can be seen that the current inner loop of VF control and PQ control is the same, and the difference lies in the control structure of the outer loop. Therefore, as long as the input of the current inner loop (i.e., the output of the outer loop) idref and iqref before and after the switching is guaranteed to be the same, smooth switching between the two states can be achieved. The specific switching strategy is as follows: Fig.10 shown.

[0134] The switching strategy is: when switching from the PQ control mode to the VF control mode, the states of switches K1 to K6 change from 1 to 2; when switching from the VF control mode to the PQ control mode, the states of switches K1 to K6 change from 2 to 1.

[0135] The switching process is analyzed as follows: When the switch positions are both 1, the inputs of the power outer loop of PQ control are Pref and Qref, achieving the purpose of controlling active and reactive power. At this time, the input of the current inner loop is equal to idref_PQ and iqref_PQ, and the input of the voltage outer loop of VF control is idref and iqref, so that the outputs idref_VF and iqref_VF after PI control can follow the current idref and iqref, thus ensuring that the current inner loop input does not suddenly change before and after the switch is switched from 1 to 2. The situation of switching the switch from 2 to 1 is similar and will not be repeated here.

[0136] The test description for isolated network operation is as follows:

[0137] Step 1: Confirm that the fan is in shutdown state and the bypass switch is disconnected;

[0138] Step 2: Close the inlet and outlet switches of the device;

[0139] Step 3: Turn on the device, switch the inverter unit VF control to PQ control, and set the active load to 10% of the rated capacity of the fan;

[0140] Step 4: After switching, the unit continues to test for more than 10 minutes;

[0141] Step 5: Record the test data.

[0142] The above preset percentage may be selected as 10%.

[0143] Perform an isolated grid operation test according to the active load power setting value and record the isolated grid operation test result data.

[0144] The grid-connected new energy unit characteristic test method includes a black start test method, specifically including:

[0145] Switch the inverter unit control mode to PQ control, calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage, and set the reactive load power setting value to zero;

[0146] Perform a black start test according to the active load power setting value and record the black start test result data. The black start test is described as follows:

[0147] Step 1: Confirm that the fan is in shutdown state and the bypass switch is disconnected;

[0148] Step 2: Close the inlet and outlet switches of the device;

[0149] Step 3: Turn on the device, set the inverter unit control mode to PQ control, set the active load to 10% of the rated capacity of the wind turbine, and set the reactive load to 0;

[0150] Step 4: The unit attempts to start under this test condition;

[0151] Step 5: If the unit starts successfully and can run stably, record the relevant test data. If the unit cannot start normally, record the fault information.

[0152] The grid-type new energy unit characteristic test method includes a frequency active support test method, specifically including:

[0153] The inverter unit control mode is switched to VF control, and the voltage amplitude generated by the inverter unit VF control system is used as the voltage amplitude of the third control test port; the inverter unit VF control system, such as Figure 5 As shown, the voltage amplitude and the output voltage amplitude V of the phase generation module can be used as the voltage amplitude of the third control test port.

[0154] Determining the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system; determining the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system includes:

[0155] The equivalent frequency model is connected in series to the voltage phase generation branch of the inverter unit VF control system;

[0156] Correspondingly, the sum of the frequency change output by the equivalent frequency model and the system power frequency is calculated, and the sum result is integrated to obtain the voltage phase of the third control test port. The system power frequency can be the operating frequency of the entire system, for example, 50Hz. The frequency active support test function is described as follows:

[0157] In the existing inertia or primary frequency modulation test standards, the frequency test curve is an ideal ramp or step curve, which is different from the frequency response of the actual power system when power disturbance occurs. In order to accurately simulate the impact of system frequency changes on the unit response, a method for generating a frequency dynamic response curve is proposed, and the corresponding program is embedded in the device control logic.

[0158] The system frequency characteristics can be expressed by the equivalent generator rotor motion equation:

[0159]

[0160] Where: Δf is the frequency change; ΔP m is the change in the equivalent generator mechanical power; ΔP d is the disturbance power; D sys is the load frequency adjustment coefficient, H sys is the system equivalent inertia.

[0161] From formula (8), we can see that the overall primary frequency modulation characteristics of the system can be equivalent to the first-order inertia link, such as Fig.11 As shown in the figure, Rsys and Tsys are the equivalent differential coefficient of the primary frequency modulation of the system and the first-order delay time constant, respectively, and Tsys is used to quantify the standard primary frequency modulation speed.

[0162] The frequency active support test is described as follows:

[0163] Step 1: Confirm that the fan is in shutdown state and the bypass switch is disconnected;

[0164] Step 2: Close the inlet and outlet switches of the device;

[0165] Step 3: Turn on the device and set the inverter unit control mode to VF control;

[0166] Step 4: Start the unit;

[0167] Step 5: Set the load frequency adjustment coefficient, primary frequency adjustment equivalent adjustment coefficient, first-order delay time constant and disturbance power of the scenario to be simulated;

[0168] Step 6: Carry out inertia and primary frequency modulation tests according to test requirements.

[0169] Step 7: Record the test data.

[0170] Perform an active frequency support test based on the voltage amplitude of the third control test port, the voltage phase of the third control test port, the load frequency adjustment coefficient of the scenario to be simulated, the primary frequency regulation equivalent adjustment coefficient, the first-order delay time constant and the disturbance power, and record the active frequency support test result data.

[0171] The grid-connected new energy unit characteristic test method provided in the embodiment of the present invention is simulated and verified as follows:

[0172] Grid strength adaptability test function:

[0173] Compare the response curves in the following two simulation scenarios:

[0174] Scenario 1: A 1.5MW wind turbine is connected to an infinite power source via system resistance and system reactance, with a short-circuit ratio of 5;

[0175] Scenario 2: The wind turbine is connected to the grid simulation device, and the device simulates a scenario with a short-circuit ratio of 5.

[0176] The positive sequence voltage, active power and reactive power at the machine end when the active power of the wind turbine changes in the two scenarios are shown in Figures 12(a) and 12(b), 13(a) and 13(b), and 14(a) and 14(b). The error is less than 0.1%, which proves that the power grid simulation device has a good simulation effect on the power grid strength.

[0177] Transient overvoltage response test function:

[0178] Compare the response curves in the following two simulation scenarios:

[0179] Scenario 1: A 1.5MW wind turbine is connected to an infinite power source via system resistance and system reactance, and a two-phase 0.2pu voltage drop fault is achieved by connecting a short-circuit branch in parallel on the high-voltage side of the box-type transformer;

[0180] Scenario 2: The wind turbine is connected to a grid simulation device, which simulates a two-phase 0.2pu voltage drop fault.

[0181] The positive sequence voltage, active power and reactive power at the wind turbine end in the two scenarios are shown in Figures 15(a) and 15(b), 16(a) and 16(b), and 17(a) and 17(b). The error is less than 0.1%, which proves that the power grid simulation device has a good simulation effect on transient overvoltage faults.

[0182] Self-built pressure test function:

[0183] Compare the response curves in the following two simulation scenarios:

[0184] Scenario 1: Infinite power source connected to actual active and reactive loads;

[0185] Scenario 2: An infinite power source is connected to a grid simulation device, which simulates the load change process.

[0186] The active power, reactive power, and phase A current in the two scenarios are shown in Figures 18(a) and 18(b), 19(a) and 19(b), and 20(a) and 20(b). The error is less than 0.1%, which proves that the power grid simulation device has a good simulation effect on active and reactive loads.

[0187] Frequency active support test:

[0188] The device is used to generate a frequency that meets the requirements of the frequency dynamic response curve, wherein the parameters are set as: Hsys=4, Dsys=5, Rsys=20, Tsys=3, ΔPd=6%.

[0189] The system frequency and wind turbine active power are shown in Figure 21(a) and Figure 21(b), which proves that the power grid simulator can be used to simulate the frequency dynamic response curve.

[0190] The grid-connected new energy unit characteristic testing method provided in an embodiment of the present invention includes a grid strength adaptability testing method, which specifically includes: switching the inverter unit control mode to VF control, and calculating the system impedance parameters corresponding to each grid strength; determining the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power within each preset power range; performing a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and recording the grid strength adaptability test result data, so as to efficiently and accurately perform a grid-connected new energy unit characteristic test.

[0191] Furthermore, the grid-connected new energy unit characteristic test method includes a transient overvoltage test method, specifically including:

[0192] The inverter unit control mode is switched to VF control, and the corresponding system impedance parameters and short-circuit impedance parameters are calculated according to the transient overvoltage condition to be simulated; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0193] According to the infinite grid phase voltage, the high-voltage side phase voltage of the unit transformer, the phase active power of the new energy unit, the phase reactive power of the new energy unit, the phase active power and phase reactive power of the grid flowing to the short-circuit branch, the system impedance parameters and the short-circuit impedance parameters, the voltage amplitude of the second control test port and the voltage phase of the second control test port are determined; the above-mentioned embodiment can be referred to for description and no further details are given.

[0194] A transient overvoltage test is performed according to the voltage amplitude of the second control test port and the voltage phase of the second control test port, and the transient overvoltage test result data is recorded. The above description can be referred to in the above embodiment and will not be repeated here.

[0195] Furthermore, the grid-connected new energy unit characteristic test method includes an isolated grid operation test method, which specifically includes:

[0196] The inverter unit control mode is switched to PQ control, and the active load power setting value is calculated based on the product of the wind turbine rated capacity and the preset percentage; the description can be made with reference to the above embodiment and will not be repeated here.

[0197] An isolated grid operation test is performed according to the active load power setting value, and the isolated grid operation test result data is recorded. The above-mentioned embodiment can be referred to for description, and no further description is given.

[0198] Furthermore, the grid-connected new energy unit characteristic test method includes a black start test method, specifically including:

[0199] The inverter unit control mode is switched to PQ control, the active load power setting value is calculated according to the product of the wind turbine rated capacity and the preset percentage, and the reactive load power setting value is set to zero; please refer to the above embodiment for description and no further details are given.

[0200] A black start test is performed according to the active load power setting value, and the black start test result data is recorded. The above-mentioned embodiment can be referred to for description, and no further description is given.

[0201] Furthermore, the grid-connected new energy unit characteristic test method includes a frequency active support test method, specifically including:

[0202] The control mode of the inverter unit is switched to VF control, and the voltage amplitude generated by the inverter unit VF control system is used as the voltage amplitude of the third control test port; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0203] According to the equivalent frequency model and the inverter unit VF control system, the voltage phase of the third control test port is determined; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0204] According to the voltage amplitude of the third control test port, the voltage phase of the third control test port, the load frequency adjustment coefficient of the scenario to be simulated, the primary frequency modulation equivalent adjustment coefficient, the first-order delay time constant and the disturbance power, the frequency active support test is performed, and the frequency active support test result data is recorded. The above-mentioned embodiment can be referred to for explanation and will not be repeated here.

[0205] Further, the determining of the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system includes:

[0206] The equivalent frequency model is connected in series to the voltage phase generation branch of the inverter unit VF control system; the above-mentioned embodiment can be referred to for description and will not be described in detail.

[0207] Correspondingly, the sum of the frequency variation output by the equivalent frequency model and the system power frequency is calculated, and the sum result is integrated to obtain the voltage phase of the third control test port.

[0208] Fig. 22 : is a schematic diagram of the structure of a network-type new energy unit characteristic testing device provided by an embodiment of the present invention, such as Fig. 22 As shown, the grid-type new energy unit characteristic testing device provided in the embodiment of the present invention includes a grid strength adaptability testing device, which specifically includes a calculation unit 2201, a determination unit 2202 and a testing unit 2203, wherein:

[0209] The calculation unit 2201 is used to switch the inverter unit control mode to VF control, and calculate the system impedance parameters corresponding to each grid strength; the determination unit 2202 is used to determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength according to each system impedance parameter, grid voltage, unit transformer high-voltage side voltage, unit transformer high-voltage side active power and unit transformer high-voltage side reactive power within each preset power range; the test unit 2203 is used to perform a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and record the grid strength adaptability test result data.

[0210] Specifically, the calculation unit 2201 in the device is used to switch the inverter unit control mode to VF control, and calculate the system impedance parameters corresponding to each grid strength; the determination unit 2202 is used to determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power within each preset power range; the test unit 2203 is used to perform a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and record the grid strength adaptability test result data.

[0211] The grid-type new energy unit characteristic test device provided in an embodiment of the present invention includes a grid strength adaptability test device, which specifically includes: switching the inverter unit control mode to VF control, and calculating the system impedance parameters corresponding to each grid strength; determining the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power within each preset power range; performing a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and recording the grid strength adaptability test result data, so as to efficiently and accurately perform a grid-type new energy unit characteristic test.

[0212] Furthermore, the grid-connected new energy unit characteristic test device includes a transient overvoltage test device, which is specifically used for:

[0213] Switch the inverter unit control mode to VF control, and calculate the corresponding system impedance parameters and short-circuit impedance parameters according to the transient overvoltage condition to be simulated;

[0214] Determine the voltage amplitude of the second control test port and the voltage phase of the second control test port according to the infinite grid phase voltage, the phase voltage on the high-voltage side of the unit box transformer, the phase active power of the new energy unit, the phase reactive power of the new energy unit, the phase active power and phase reactive power of the grid flowing to the short-circuit branch, the system impedance parameters and the short-circuit impedance parameters;

[0215] A transient overvoltage test is performed according to the voltage amplitude of the second control test port and the voltage phase of the second control test port, and transient overvoltage test result data is recorded.

[0216] Furthermore, the grid-connected new energy unit characteristic test device includes an isolated grid operation test device, which is specifically used for:

[0217] Switch the inverter unit control mode to PQ control, and calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage;

[0218] Perform an isolated grid operation test according to the active load power setting value and record the isolated grid operation test result data.

[0219] Furthermore, the grid-connected new energy unit characteristic test device includes a black start test device, which is specifically used for:

[0220] Switch the inverter unit control mode to PQ control, calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage, and set the reactive load power setting value to zero;

[0221] Perform a black start test according to the active load power setting value and record the black start test result data.

[0222] Furthermore, the network-type new energy unit characteristic test device includes a frequency active support test device, which is specifically used for:

[0223] Switch the inverter unit control mode to VF control, and use the voltage amplitude generated by the inverter unit VF control system as the voltage amplitude of the third control test port;

[0224] Determine the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system;

[0225] Perform an active frequency support test based on the voltage amplitude of the third control test port, the voltage phase of the third control test port, the load frequency adjustment coefficient of the scenario to be simulated, the primary frequency regulation equivalent adjustment coefficient, the first-order delay time constant and the disturbance power, and record the active frequency support test result data.

[0226] Furthermore, the frequency active support test device is also specifically used for:

[0227] The equivalent frequency model is connected in series to the voltage phase generation branch of the inverter unit VF control system;

[0228] Correspondingly, the sum of the frequency variation output by the equivalent frequency model and the system power frequency is calculated, and the sum result is integrated to obtain the voltage phase of the third control test port.

[0229] The embodiment of the present invention provides an embodiment of a grid-type new energy unit characteristic testing device, which can be specifically used to execute the processing flow of the above-mentioned method embodiments. Its functions are not repeated here, and reference can be made to the detailed description of the above-mentioned method embodiments.

[0230] Fig.23 A schematic diagram of the physical structure of a computer device provided in an embodiment of the present invention is shown in FIG. Fig.23As shown, the computer device includes: a memory 2301, a processor 2302, and a computer program stored in the memory 2301 and executable on the processor 2302. When the processor 2302 executes the computer program, the following method is implemented:

[0231] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0232] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0233] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0234] This embodiment discloses a computer program product, the computer program product including a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0235] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0236] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0237] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0238] This embodiment provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0239] Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength;

[0240] Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power;

[0241] A grid strength adaptability test is performed according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and grid strength adaptability test result data is recorded.

[0242] Compared with the technical solutions in the prior art, the grid-connected new energy unit characteristic testing method provided in the embodiment of the present invention switches the inverter unit control mode to VF control, and calculates the system impedance parameters corresponding to each grid strength; determines the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power; performs a grid strength adaptability test according to the first control test port voltage amplitude and the first control test port voltage phase, and records the grid strength adaptability test result data, so as to efficiently and accurately perform a grid-connected new energy unit characteristic test.

[0243] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0244] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0245] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0246] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0247] In the description of this specification, the description with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0248] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for testing the characteristics of a grid-connected new energy unit, characterized in that: The grid-connected new energy unit characteristic test method includes a grid strength adaptability test method, specifically including: Switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength; Determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power; Performing a grid strength adaptability test according to the voltage amplitude of the first control test port and the voltage phase of the first control test port, and recording grid strength adaptability test result data; The grid-connected new energy unit characteristic test method includes a transient overvoltage test method, specifically including: Switch the inverter unit control mode to VF control, and calculate the corresponding system impedance parameters and short-circuit impedance parameters according to the transient overvoltage condition to be simulated; Determine the voltage amplitude of the second control test port and the voltage phase of the second control test port according to the infinite grid phase voltage, the phase voltage on the high-voltage side of the unit box transformer, the phase active power of the new energy unit, the phase reactive power of the new energy unit, the phase active power and phase reactive power of the grid flowing to the short-circuit branch, the system impedance parameters and the short-circuit impedance parameters; A transient overvoltage test is performed according to the voltage amplitude of the second control test port and the voltage phase of the second control test port, and transient overvoltage test result data is recorded.

2. The method for testing the characteristics of a grid-connected new energy generator set according to claim 1, characterized in that: The grid-connected new energy unit characteristic test method includes an isolated grid operation test method, specifically including: Switch the inverter unit control mode to PQ control, and calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage; Perform an isolated grid operation test according to the active load power setting value and record the isolated grid operation test result data.

3. The method for testing the characteristics of a grid-connected new energy generator set according to claim 1, characterized in that: The grid-connected new energy unit characteristic test method includes a black start test method, specifically including: Switch the inverter unit control mode to PQ control, calculate the active load power setting value based on the product of the wind turbine rated capacity and the preset percentage, and set the reactive load power setting value to zero; Perform a black start test according to the active load power setting value and record the black start test result data.

4. The method for testing the characteristics of a grid-connected new energy generator set according to claim 1, characterized in that: The grid-type new energy unit characteristic test method includes a frequency active support test method, specifically including: Switch the inverter unit control mode to VF control, and use the voltage amplitude generated by the inverter unit VF control system as the voltage amplitude of the third control test port; Determine the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system; Perform an active frequency support test based on the voltage amplitude of the third control test port, the voltage phase of the third control test port, the load frequency adjustment coefficient of the scenario to be simulated, the primary frequency regulation equivalent adjustment coefficient, the first-order delay time constant and the disturbance power, and record the active frequency support test result data.

5. The method for testing the characteristics of a grid-connected new energy generator set according to claim 4 is characterized in that: The step of determining the voltage phase of the third control test port according to the equivalent frequency model and the inverter unit VF control system includes: The equivalent frequency model is connected in series to the voltage phase generation branch of the inverter unit VF control system; Correspondingly, the sum of the frequency variation output by the equivalent frequency model and the system power frequency is calculated, and the sum result is integrated to obtain the voltage phase of the third control test port.

6. A grid-type new energy unit characteristic test device, characterized in that: The grid-connected new energy unit characteristic test device includes a grid strength adaptability test device, specifically including: A calculation unit, used to switch the inverter unit control mode to VF control and calculate the system impedance parameters corresponding to each grid strength; A determination unit, used to determine the first control test port voltage amplitude and the first control test port voltage phase corresponding to each grid strength respectively within each preset power range according to each system impedance parameter, grid voltage, unit box transformer high-voltage side voltage, unit box transformer high-voltage side active power and unit box transformer high-voltage side reactive power; A testing unit, used to perform a grid strength adaptability test according to a voltage amplitude of a first control test port and a voltage phase of a first control test port, and record grid strength adaptability test result data; The grid-type new energy unit characteristic test device includes a transient overvoltage test device, which is specifically used for: Switch the inverter unit control mode to VF control, and calculate the corresponding system impedance parameters and short-circuit impedance parameters according to the transient overvoltage condition to be simulated; Determine the voltage amplitude of the second control test port and the voltage phase of the second control test port according to the infinite grid phase voltage, the phase voltage on the high-voltage side of the unit box transformer, the phase active power of the new energy unit, the phase reactive power of the new energy unit, the phase active power and phase reactive power of the grid flowing to the short-circuit branch, the system impedance parameters and the short-circuit impedance parameters; A transient overvoltage test is performed according to the voltage amplitude of the second control test port and the voltage phase of the second control test port, and transient overvoltage test result data is recorded.

7. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

9. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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