Multi-level full-scene network-building type fan grid-connected test method

Abstract

The invention provides a multi-level and full-scene grid-connection test method for a network-forming type fan, and develops a set of test method covering multi-level and full-scene, so that the performance of the network-forming type fan in different scenes and working conditions is effectively evaluated, and the safety and stability of grid connection of the fan are ensured; the invention discloses a multi-level full-scene networking type fan grid-connected test method, which comprises a networking type fan networking characteristic test method, a networking type wind power plant grid-connected test method, a network following and networking fan combined operation test method and a network following and networking wind power plant combined operation test method.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine grid-connected testing, and in particular to a multi-level, full-scenario grid-connected wind turbine testing method and system. Background Art

[0002] As the global demand for renewable energy continues to grow, wind energy, as one of the clean and renewable energy forms, has received increasing attention for its development and utilization. Wind power technology has undergone a transformation from the traditional grid-following (GFL) wind power system to the more advanced grid-forming (GFM) wind power system. The grid-following wind power system mainly relies on the voltage and frequency support of the power grid, while the grid-forming wind power system has the ability to autonomously maintain voltage and frequency stability under weak power grid or even island conditions, which is of great significance for improving the flexibility and reliability of the wind power system.

[0003] However, with the rapid development of grid-connected wind power technology, how to comprehensively and effectively evaluate its grid-connected performance in different scenarios has become an urgent problem to be solved. At present, there is no unified test method for grid-connected wind farms, and there is a lack of a systematic and comprehensive evaluation system, which makes it difficult to fully reflect the various characteristics and problems of wind farms in actual operation. Grid-connected wind farms have the ability to provide voltage and frequency support in the event of a grid failure, but their performance directly affects the safe and stable operation of the grid. Therefore, developing a comprehensive and scientific test method to evaluate the grid-connected performance of grid-connected wind farms is an important prerequisite for ensuring the safe and stable operation of the power grid.

[0004] The grid connection test of wind farms faces a variety of application scenarios, including grid-connected wind farm grid characteristics test, grid-connected wind farm grid test, grid-connected and grid-connected wind turbine joint operation test, and grid-connected and grid-connected wind farm joint operation test. Therefore, developing a set of test methods covering multiple levels and all scenarios will help meet the testing needs in different application scenarios, promote the widespread application of wind power technology, effectively evaluate the performance of grid-connected wind farms in different scenarios and working conditions, and provide strong support for the further development and application of wind turbine technology. Summary of the invention

[0005] The present invention aims to address the technical defects of the prior art and provide a multi-level, full-scenario grid-connected wind turbine testing method, develop a set of testing methods covering multi-level and full-scenario, effectively evaluate the performance of grid-connected wind turbines in different scenarios and working conditions, and ensure the safety and stability of wind turbine grid connection.

[0006] The present invention discloses a multi-level, full-scenario grid-connected test method for grid-connected wind turbines, including a grid-connected wind turbine characteristic test method, a grid-connected wind farm test method, a grid-connected and grid-connected wind turbine joint operation test method, and a grid-connected and grid-connected wind farm joint operation test method.

[0007] Preferably, the method for testing the network characteristics of a network-type wind turbine performs any one or more of the following steps:

[0008] Step 1: low and high voltage cascading fault ride-through capability test, including low and high voltage cascading fault ride-through no-load test and low and high voltage cascading fault ride-through load test;

[0009] Step 2: Low voltage ride through capability test, including low voltage ride through no-load test and low voltage ride through load test;

[0010] Step 3: High voltage ride through capability test, including high voltage ride through no-load test and high voltage ride through load test;

[0011] Step 4: frequency deviation adaptability test, including frequency adaptability no-load test and frequency adaptability load test;

[0012] Step 5, a frequency modulation test, including a frequency modulation dead zone test, a frequency step disturbance test, and a frequency modulation limit test;

[0013] Step 6, inertia response test, including inertia response no-load test and inertia response load test;

[0014] Step 7, voltage deviation adaptability test, including voltage deviation adaptability no-load test and voltage deviation adaptability load test;

[0015] Step 8: Power quality adaptability test, including harmonic voltage adaptability test, three-phase voltage unbalance adaptability test, and flicker adaptability test;

[0016] Step 9, voltage phase mutation adaptability test, including voltage phase mutation adaptability no-load test and voltage phase mutation adaptability load test;

[0017] Step 10, network following and network building mode switching test, including network building to network following mode switching test, network following to network building mode switching test;

[0018] Step 11, reactive power regulation capability test, including reactive power response capability based on control, maximum inductive reactive power, maximum capacitive reactive power test, reactive power response capability based on control, reactive power set value control mode operation capability test, reactive power response capability based on control, reactive power step change test, voltage jump reactive power response no-load test, voltage jump reactive power response load test;

[0019] Step 12, active power regulation capability test, including active power regulation capability maximum measured power test, active power regulation capability rise rate limit test, active power regulation capability set value control test;

[0020] Step 13, damping control test;

[0021] Step 14: Overload capacity test.

[0022] Preferably, the grid-type wind turbine network characteristics testing method includes a grid-type wind turbine single-machine network characteristics testing method and a grid-type wind turbine multi-machine coordinated control testing method.

[0023] Preferably, the single-machine network characteristic test method of the grid-type wind turbine is used to verify whether the grid-type wind turbine meets the low- and high-voltage cascading fault ride-through requirements, and executes any one or more of the steps 1-14:

[0024] The low and high voltage interlocking fault riding no-load test in step 1 adopts step 1-1: adjusting the voltage fault generating device to simulate the low and high voltage interlocking faults of the three-phase voltage and the two-phase voltage of the line, the voltage drop value is 0.15-0.25pu, the duration is 605-645ms; the voltage rise value is 1.27-1.33pu, the duration is 480-520ms, wherein the voltage drop and voltage rise interval time is 0-10ms, and the voltage curve of the wind turbine grid connection point is recorded by using a data acquisition device;

[0025] The high voltage cascading fault ride-through load test in step 1 includes the following steps using steps 1-2:

[0026] Step 1-2-1, put the fan disconnected during the no-load test into operation and connect it to the test equipment;

[0027] Step 1-2-2, adjust the fan output power to 0.1~0.3pn;

[0028] Step 1-2-3, control the voltage fault generating device to perform three-phase symmetrical voltage drop and rise, the voltage drop value is 0.15~0.25pu, the duration is 605~645ms, the voltage rise value is 1.27~1.33pu, the duration should be 480~520ms, and the voltage drop and voltage rise interval should be 0~10ms;

[0029] Step 1-2-4, use a data acquisition device to record the waveforms of the voltage and current at the wind turbine grid connection point, and record the data from 10 seconds before the voltage drops to more than 15 seconds after the voltage returns to normal, and do it twice for each point;

[0030] Step 1-2-5, adjust the fan output power to 0.9pn, and repeat steps (1-2-3) to (1-2-4);

[0031] Step 1-2-6, control the voltage fault generating device to drop and raise the two-phase voltage. The voltage drop value should be 0.15-0.25 pu, the duration should be 605-645 ms, the voltage increase value should be 1.27-1.33 pu, the duration should be 480-520 ms, and the voltage drop and voltage increase interval should be 0-10 ms. Repeat steps (1-2-4) to (1-2-5);

[0032] The low voltage ride-through no-load test in step 2 adopts step 2-1: adjusting the power grid simulation device to simulate the reduction of the three-phase voltage and the two-phase voltage of the line. When simulating the three-phase voltage reduction, the voltage amplitude is adjusted to 0.15-0.25pu for a test, the duration is 99980-100020ms, and the unit is disconnected from the power grid; when simulating the two-phase voltage reduction, the voltage amplitude is adjusted to 0.15-0.25pu for a test, the duration is 99980-100020ms, and the unit is disconnected from the power grid. The data acquisition device is used to record the voltage curve of the wind turbine grid connection point;

[0033] The low voltage ride through load test in step 2 includes the following steps using step 2-2:

[0034] Step 2-2-1, put the fan disconnected during the no-load test into operation and connect it to the test equipment;

[0035] Step 2-2-2, fan output power 0.1~0.3pn;

[0036] Step 2-2-3, control the power grid simulation device to perform three-phase symmetrical voltage reduction, first adjust the voltage amplitude to 0.85~0.95pu for two tests, the duration is 99980~100020ms, and then adjust the voltage amplitude range to 0.70~0.80pu, 0.45~0.55pu, 0.30~0.40pu, 0.15~0.25pu gradients and repeat the test in sequence;

[0037] Step 2-2-4, use a data acquisition device to record the waveforms of the voltage and current at the wind turbine grid connection point, and record the data from 10 seconds before the voltage drops to more than 15 seconds after the voltage returns to normal, and do it twice for each point;

[0038] Step 2-2-5, adjust the fan power to be greater than 0.9pn, and repeat steps (2-2-3) to (2-2-4);

[0039] Step 2-2-6, control the power grid simulation device to reduce the two-phase voltage, first adjust the voltage amplitude to the range of 0.85~0.95pu and perform two tests, the duration should be 99980~100020ms, and then adjust the voltage amplitude range to 0.70~0.80pu, 0.45~0.55pu, 0.30~0.40pu, 0.15~0.25pu in sequence, and repeat the test, and repeat steps (2-2-4)~(2-2-5).

[0040] In the step 3, the high voltage ride through no-load test adopts step 3-1: adjust the grid simulation device to simulate the increase of the three-phase voltage and the two-phase voltage of the line. When simulating the three voltage increases, adjust the voltage amplitude to 1.17-1.23pu for a test, the duration is 99980-100020ms, the unit is disconnected from the grid, and then set the voltage amplitude range to 1.22-1.28pu and 1.27-1.33pu respectively for another test, the duration is 9 9980~100020ms, when simulating two voltage reductions, adjust the voltage amplitude to 1.17~1.23pu for a test, the duration is 99980~100020ms, the unit operating condition should be disconnected from the grid, and then set the voltage amplitude range to 1.22~1.28pu and 1.27~1.33pu respectively for another test, the duration is 99980~100020ms, and use the data acquisition device to record the voltage curve of the wind turbine grid connection point;

[0041] The high voltage ride through load test in step 3 includes the following steps using step 3-2:

[0042] Step 3-2-1, put the fan disconnected during the no-load test into operation and connect it to the test equipment;

[0043] Step 3-2-2, adjust the fan output power between 0.1 and 0.3 pn;

[0044] Step 3-2-3, control the power grid simulation device to perform three-phase symmetrical voltage raising, first adjust the voltage amplitude to the range of 1.17-1.23pu for two tests, the duration is 99980-100020ms, and then repeat the test in the voltage amplitude range of 1.22-1.28pu and 1.27-1.33pu in sequence;

[0045] Step 3-2-4, use a data acquisition device to record the waveforms of the voltage and current at the wind turbine grid connection point, and record the data from 10 seconds before the voltage rises to more than 15 seconds after the voltage returns to normal, and do it twice for each point;

[0046] Step 3-2-5, adjust the fan output power to 0.9pn, and repeat steps (3-2-3) to (3-2-4);

[0047] Step 3-2-6, control the power grid simulation device to raise the two-phase voltage, first adjust the voltage amplitude to 1.17~1.23pu for two tests, the duration should be 99980~100020ms, and then adjust the voltage amplitude range to 1.22~1.28pu and 1.27~1.33pu in gradients to repeat test steps (3-2-4)~(3-2-4) in sequence;

[0048] The frequency deviation adaptability test in step 4 adopts step 4-1: adjusting the output frequency of the power grid adaptability detection device to 48-51.5Hz, the step length of the frequency adjustment is 0.1Hz, the duration of each step length is greater than 5s, and the actual frequency measured value and the corresponding adjustment parameter are recorded for each adjustment; adjusting the output frequency of the test device to gradually adjust from the rated frequency to 48Hz, 48.5Hz, 49Hz, 49.9Hz, 50.1Hz, 50.5Hz, 51Hz, 51.5Hz, the duration of each frequency setting value is greater than 5s, and the actual frequency measured value and the corresponding adjustment parameter are recorded for each adjustment;

[0049] The frequency adaptability load test in step 4 adopts either step 4-2 or step 4-3:

[0050] Step 4-2: The wind turbine operates normally and does not participate in system frequency regulation. During the test, the active power output of the wind turbine is greater than 10% of the rated power. The test adopts the following steps:

[0051] (1) Keep the wind turbine in normal operation under rated voltage conditions, adjust the test device to gradually increase the frequency from the rated frequency in steps of 0.1 Hz, and each step should last for more than 20 seconds. When the frequency rises to 51.5 Hz, the test duration at this point shall not be less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid;

[0052] (2) Keep the wind turbine in normal operation under rated voltage conditions, adjust the test device to gradually reduce the frequency from the rated frequency in steps of 0.1 Hz, and each step lasts for more than 20 seconds. When the frequency drops to 48 Hz, the test duration at this point is not less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid;

[0053] Step 4-3: The wind turbine generator set operates under the condition of limited power and frequency modulation. During the test, the active power output of the wind turbine generator set is greater than 20% of the rated power. The test adopts the following steps:

[0054] (1) Under rated voltage conditions, adjust the output frequency of the test device from the rated value to 48 Hz, 48.5 Hz, 49 Hz, 49.9 Hz, 50.1 Hz, 50.5 Hz, 51 Hz, and 51.5 Hz. The frequency retention time shall not be less than 30 s. After the frequency returns to the rated value, the test retention time shall not be less than 10 s. During the test, record whether the wind turbine is disconnected from the grid;

[0055] (2) Under rated voltage conditions, set the output frequency of the test device one by one in the order of 48 Hz, 48.5 Hz, 49 Hz, 49.9 Hz, 50.1 Hz, 50.5 Hz, 51 Hz, and 51.5 Hz, and repeat step 4-2;

[0056] The one-time frequency modulation dead zone test in step 5 includes the following steps using step 5-1:

[0057] Step 5-1-1, set the primary frequency modulation parameters of the grid-type fan, and connect the grid-type fan and related testing and measuring equipment;

[0058] Step 5-1-2, adjust the grid-type fan to operate in no-load mode;

[0059] Step 5-1-3, gradually increase the grid connection point frequency value with a step size of 0.01Hz until the active power starts to change regularly. Each frequency setting value runs for 5s, and the output frequency value at the time when the active power changes regularly during the frequency disturbance process is recorded;

[0060] Step 5-1-4, gradually reduce the grid connection point frequency value with a step size of 0.01Hz until the active power starts to change regularly. Run each frequency setting value for 5s, record the output frequency value steps at the time when the active power changes regularly during the frequency disturbance process, and repeat steps (5-1-3) to (5-1-4);

[0061] Step 5-1-5, adjusting the grid-type fan to operate in pn constant power load mode;

[0062] Step 5-1-6, adjust the grid-type fan to operate at no less than 20% pn, and repeat steps (5-1-3) to (5-1-4);

[0063] The frequency step disturbance test in step 5, using step 5-2, includes the following steps:

[0064] Step 5-2-1, connect the data acquisition device to the voltage transformer and current transformer at the test point, and connect the frequency signal generator to the grid-type wind turbine monitoring system;

[0065] Step 5-2-2, adjust the grid-type fan to operate in no-load mode;

[0066] Step 5-2-3, the grid-type wind turbine is respectively under the unlimited power and limited power operation states, and the active power is tested according to the grid-type wind turbine operation state and power range;

[0067] Step 5-2-4, using a frequency signal generator to output a frequency step disturbance signal from 50 Hz to 50.15 Hz, 50 Hz to 50.205 Hz, 50 Hz to 49.85 Hz, and 50 Hz to 49.80 Hz, and each working condition is tested twice;

[0068] Step 5-2-5, record the voltage, current, frequency and power values ​​during the test;

[0069] Step 5-2-6, calculate the primary frequency modulation response lag time, rise time, adjustment time and active power control deviation;

[0070] Step 5-2-7, adjust the grid-type fan to operate in pn constant power no-load mode;

[0071] Step 5-2-8, using a frequency signal generator to output a frequency step disturbance signal from 50 Hz to 50.15 Hz, 50 Hz to 50.205 Hz, 50 Hz to 49.85 Hz, and 50 Hz to 49.80 Hz, and each operating condition is tested twice;

[0072] Step 5-2-9, record the voltage, current, frequency and power values ​​during the test;

[0073] Step 5-2-10, calculate the frequency modulation response lag time, rise time, adjustment time and active power control deviation, the active power control deviation calculation formula is: in

[0074] ΔP t is the change in active power of the wind farm, K f is the active frequency modulation coefficient, ff is the power system frequency deviation, f N is the rated frequency of the power system, P t is the active power of the wind farm;

[0075] The one-time frequency modulation amplitude limiting test in step 5, using step 5-3, includes the following steps:

[0076] Step 5-3-1, connect the data acquisition device to the voltage transformer and current transformer of the test point, and connect the frequency signal generator to the grid-type wind turbine monitoring system;

[0077] Step 5-3-2, adjust the grid-type fan to operate in no-load mode;

[0078] Step 5-3-3, set the frequency value of the grid connection point to gradually increase in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s, and the frequency difference step does not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process;

[0079] Step 5-3-4, set the frequency value of the grid connection point to gradually decrease in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s, and the frequency difference step does not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process;

[0080] Step 5-3-5, adjust the grid-type fan to operate in pn constant power no-load mode;

[0081] Step 5-3-6, adjust the grid-type fan to operate at 20% pn, and repeat steps (5-3-3) to (5-3-6);

[0082] The inertia response no-load test in step 6 adopts step 6-1: adjusting the output frequency of the grid adaptability detection device from 50 Hz, and changing it to 51.5 Hz at a change rate of 0.1 Hz / s, 0.5 Hz / s, and 1 Hz / s respectively, maintaining the frequency for no less than 10 seconds after stabilization, and restoring it to 50 Hz at the same change rate; repeating the above process, adjusting the frequency from 50 Hz to 48 Hz, and then restoring it to 50 Hz, and recording the actual frequency value and the corresponding adjustment parameter during each adjustment;

[0083] The inertia response load test in step 6 includes the following steps using step 6-2:

[0084] Step 6-2-1, keep the wind turbine in normal operation under rated voltage conditions, adjust the output frequency of the test device from 50Hz to 51.5Hz at a change rate of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, keep the test time for no less than 10s. After the frequency returns to the rated value at the same frequency change rate, keep the test time for no less than 10s. During the test, record whether the wind turbine is off the grid;

[0085] Step 6-2-2, keep the wind turbine in normal operation under rated voltage conditions, adjust the output frequency of the test device from 50Hz to 48Hz at a change rate of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, keep the test time for no less than 10s. After the frequency returns to the rated value at the same frequency change rate, keep the test time for no less than 10s. During the test, record whether the wind turbine is off the grid;

[0086] The voltage deviation adaptability no-load test in step 7 adopts step 7-1:

[0087] When the wind turbine is disconnected from the grid, adjust the output voltage of the grid adaptability detection device from 0.9pu to 1.1pu. The voltage adjustment steps are 1% and 2% of the rated voltage respectively. The duration of each step is not less than 5s. Record the measured voltage value and the corresponding adjustment parameters for each adjustment.

[0088] The voltage deviation adaptability load test in step 7 includes the following steps using step 7-2:

[0089] Step 7-2-1, keep the wind turbine in normal operation under rated frequency conditions, adjust the test device to gradually increase the voltage from the rated voltage in steps of 1% and 2% of the rated voltage, and each step lasts for no less than 20 seconds. When the voltage rises to 1.10pu, the test duration at this point is no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid;

[0090] Step 7-2-2, keep the wind turbine in normal operation under rated frequency conditions, adjust the test device to gradually reduce the voltage from the rated voltage in steps of 1% and 2% of the rated voltage, and each step should last for no less than 20 seconds. When the voltage drops to 0.90pu, the test duration at this point shall be no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid;

[0091] The harmonic voltage adaptability test in step 8 includes the following steps using step 8-1:

[0092] Step 8-1-1, maintain normal operation of the unit under rated voltage and rated frequency conditions;

[0093] Step 8-1-2, set the adjustment parameter to the set value of the 5Hz interharmonic voltage content rate during no-load test. If the wind turbine is not disconnected from the grid after the corresponding adjustment parameter lasts for 2 minutes, stop the test; if the wind turbine is disconnected from the grid, record the test duration and the wind turbine disconnection time;

[0094] Step 8-1-3: The interharmonic voltage adaptability test method adopts step 8-1-2;

[0095] Step 8-1-4, restore the voltage and frequency to the rated conditions and keep the unit running normally, set the adjustment parameters to the adjustment parameters corresponding to the set value of the third harmonic content rate during the no-load test, and stop the test if the wind turbine is not disconnected from the grid after 2 minutes. If the wind turbine is disconnected from the grid, record the test duration and the wind turbine disconnection time;

[0096] Step 8-1-5: odd harmonic voltage adaptability test method adopts step 8-1-4;

[0097] Step 8-1-6, restore the voltage and frequency to the rated conditions and keep the unit running normally, set the adjustment parameters to the adjustment parameters corresponding to the set value of the second harmonic content rate during the no-load test, and stop the test if the wind turbine is not disconnected from the grid after 2 minutes. If the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid;

[0098] Step 8-1-7, the even harmonic voltage adaptability test method adopts step 8-1-6;

[0099] The three-phase voltage unbalance adaptability test in step 8 includes the following steps using step 8-2:

[0100] Step 8-2-1, three-phase voltage unbalance adaptability no-load test, restore the output voltage and frequency of the grid adaptability detection device to maintain the rated value, set and adjust the three-phase voltage unbalance degree to 2% and 4% respectively, continue to run for 30min and 1min, and record the corresponding three-phase unbalance voltage value;

[0101] Step 8-2-1, three-phase voltage unbalanced adaptive load test. The output voltage and frequency of the grid adaptability detection device are maintained at the rated value. The wind turbine is set to unity power factor control. During the test, the active power output of the wind turbine is greater than 50% of the rated power. The three-phase voltage unbalance is set to 2% and 4% respectively. The test lasts for 30 minutes and 1 minute, and the corresponding three-phase unbalanced voltage value is recorded.

[0102] The flicker adaptability test in step 8 includes the following steps using step 8-3:

[0103] Step 8-3-1, flicker adaptability no-load test, restore the grid adaptability detection device output voltage and frequency to maintain the rated value, set and adjust the three-phase voltage imbalance to 2% and 4% respectively, continue to run for 30min and 1min, and record the corresponding three-phase unbalanced voltage value;

[0104] Step 8-3-2, flicker adaptive load test, the wind turbine is set to unity power factor control, during the test, the active power output of the wind turbine is greater than 30% of the rated power, the unit is kept in normal operation under the conditions of rated voltage and rated frequency, and the same adjustment parameters as the no-load test are set. If the wind turbine is not disconnected from the grid after 10 minutes, the test is stopped. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded;

[0105] The voltage phase mutation adaptability no-load test in step 9 adopts step 9-1, when the wind turbine is disconnected from the grid, when the power supply voltage deviation at the test point is within the limit range of 0.9pu to 1.1pu, a test device is used to generate the required voltage phase mutation at the test point, and the voltage phase mutation angles are set to 5°, 30°, -5°, and -50° respectively, and the test is maintained for 30 seconds without disconnection from the grid. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded;

[0106] The voltage phase mutation adaptive load test in step 9 adopts step 9-2. During the test, the active power output of the wind turbine is greater than 30% of the rated power. When the supply voltage deviation of the test point is within the limit range of 0.9pu to 1.1pu, the test device is used to generate the required voltage phase mutation at the test point. The voltage phase mutation angles are set to 5°, 30°, -5°, and -50° respectively. The wind turbine should be kept running without disconnecting from the grid for 30 seconds. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded.

[0107] The test of switching from network building mode to network following mode in step 10 adopts step 10-1 including the following steps: step 10-1-1,

[0108] Adjust the grid-forming fans to operate in the grid-forming mode;

[0109] Step 10-1-2, adjust the grid-type fan to operate at 50% pn and run continuously for 3 minutes;

[0110] Step 10-1-3, switch the grid-type wind turbine mode to the grid-following operation mode;

[0111] Step 10-1-4, record the voltage, current and power of the grid-connected wind turbine;

[0112] Step 10-1-5, perform phase angle jump tolerance test, with an angle range of 15° to 30°;

[0113] Step 10-1-6, record the status of the grid-forming wind turbine and confirm whether the grid-forming wind turbine has switched to the grid-following operation mode;

[0114] Step 10-1-7, adjust the grid-type fan to run at 50% pn, run continuously for 3 minutes, and repeat steps (10-1-3) to (10-1-6);

[0115] The switching test from following the network to building the network in step 10 adopts step 10-2 including the following steps: step 10-2-1,

[0116] Adjust the grid-type fans to operate in the grid-following mode;

[0117] Step 10-2-2, adjust the grid-type fan to operate at 50% pn and run continuously for 3 minutes;

[0118] Step 10-2-3, switch the grid-forming wind turbine mode to the grid-forming operation mode;

[0119] Step 10-2-4, record the voltage, current and power of the grid-connected wind turbine;

[0120] Step 10-2-5, perform phase angle jump tolerance test, with an angle range of 15° to 30°;

[0121] Step 10-2-6, record the state of the grid-type fan and confirm whether the grid-type fan is switched to the grid-type operation mode;

[0122] Step 10-2-7, adjust the grid-type fan to run at 50% pn, run continuously for 3 minutes, and repeat steps (10-2-3) to (10-2-6);

[0123] The reactive power response capability maximum inductive reactive power and maximum capacitive reactive power test based on control in step 11 includes the following steps using step 11-1:

[0124] Step 11-1-1, only collect data in the continuous operation state;

[0125] Step 11-1-2, setting the active power of the wind turbine power station to pn, and adjusting the wind turbine power station to operate in a working mode of outputting the maximum inductive reactive power;

[0126] Step 11-1-3, respectively adjust the charging active power of the wind power station to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn and 0, and measure the active power and reactive power at the output end of the grid-type wind turbine;

[0127] Step 11-1-4, for each 10% rated power interval, collect at least 30 1-min active power and reactive power time series measurement data;

[0128] Step 11-1-5, in each 1-min time period, the sampled data is converted into a 1-min average value using a block average method;

[0129] Step 11-1-6, sorting the 1-min average value according to the interval method, and indicating in a table the average interval value of reactive power corresponding to the active power output of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the rated power;

[0130] Step 11-1-7, adjust the wind turbine power station to operate in the maximum inductive reactive power output working mode, and repeat steps (11-1-3) to (11-1-6);

[0131] The reactive power response capability based on the control in step 11 and the capability test of the reactive power set point control mode operation, using step 11-2, includes the following steps:

[0132] Step 11-2-1, only collect data in the continuous operation state;

[0133] Step 11-2-2, set the active power of the wind turbine power station to pn, adjust the charging active power of the wind turbine power station to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn and 0 respectively, and measure the active power and reactive power at the output end of the grid-type wind turbine;

[0134] Step 11-2-3, for each 10% rated power interval, collect at least 30 1-min active power and reactive power time series measurement data;

[0135] Step 11-2-4, in each 1-min time period, the sampled data is converted into a 1-min average value using a block average method;

[0136] Step 11-2-5, sorting the 1-min average value according to the interval method, and presenting the reactive power setting value control capability test results in a chart form, and indicating in the table the reactive power average interval values ​​corresponding to the active power output of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the rated power;

[0137] The reactive power step change test of reactive power response capability based on control in step 11 adopts step 11-3 to collect data under continuous operation, measure active power and reactive power at the output end of the grid-type wind turbine, the active power output is 50% of the rated power, the active power measurement result is the 1-min average value, the reactive power test result is the 0.2-s average value, and the reactive power adjustment should last for no less than 2 minutes under the capacitive reactive full-generation state and last for no less than 2 minutes under the inductive reactive full-generation state;

[0138] In the step 11, the voltage jump reactive power response no-load test based on control is carried out by adopting step 11-4, adjusting the power grid simulation device, simulating the line three-phase voltage to rise to 1.1pu for a duration of not less than 625ms, adjusting the power grid simulation device, simulating the line three-phase voltage to drop to 0.9pu for a duration of not less than 625ms, and recording the grid-connected point voltage curve of the grid-type wind turbine;

[0139] The voltage jump reactive power response load test in step 11 includes the following steps using step 11-5:

[0140] Step 11-5-1, connect the grid-connected wind turbine disconnected during the no-load test to the grid for operation;

[0141] Step 11-5-2, adjust the output power of the grid-type fan to 0.1-0.3pn;

[0142] Step 11-5-3, control the power grid simulation device to perform symmetrical three-phase voltage disturbance, simulate the line three-phase voltage rise to 1.1pu for not less than 30 minutes, adjust the power grid simulation device, simulate the line three-phase voltage drop to 0.9pu for not less than 30 minutes;

[0143] Step 11-5-4, record the waveforms of voltage and current at the grid-connected point of the grid-connected wind turbine, and record the data from 10 seconds before the voltage disturbance to more than 6 seconds after the voltage returns to normal, and do it twice for each point;

[0144] Step 11-5-5, adjust the grid-type fan output power to 0.9pn, and repeat steps (11-5-3) to (11-5-4);

[0145] The maximum measured power test of the active power regulation capability in step 12 adopts step 12-1 to collect data in the continuous operation state, measure the active power at the output end of the grid-type wind turbine, cut in the wind speed to 15m / s, and collect at least 5 10min time series of power measurement data for each 1m / s wind speed interval. The wind speed measurement result is the 10min average value. The power measurement data is converted into the 0.2s average value and the 1min average value within the measurement period by block averaging. When measuring the current, the full scale range should be twice the rated current of the grid-type wind turbine;

[0146] In the step 12, the active power regulation capacity increase rate limit test is performed, using step 12-2, the grid-type wind turbine is started from the shutdown state, the power increase rate is set to 10% of the rated power / min, and the grid-type wind turbine is tested for 10 minutes after being connected to the grid. During the entire test process, the active power output obtained should be at least 50% of the rated power. The active power is measured at the output end of the grid-type wind turbine, and the test result in the report should be the average value of the active power every 0.2s;

[0147] The active power regulation capability setting value control test in step 12 includes the following steps using step 12-3:

[0148] Step 12-3-1: within the first 24 hours when the wind farm predicts that the average wind speed can meet the output power of the wind farm to reach more than 80% of the rated capacity of the wind farm, inquire about the power forecast results of surrounding wind farms. If the forecast results are close, report the estimated start time of the test to the dispatcher and prepare to start the test;

[0149] Step 12-3-2: On-site personnel pay close attention to the ultra-short-term forecast of the wind power prediction system of the wind farm. If the predicted wind speed increases, they will formally apply to the dispatcher to start the test. During the test, the active power control mode of the wind farm under test is adjusted to the local control mode, and the wind farm will automatically issue the active power output command of the self-synchronous voltage source of the grid-forming wind turbine;

[0150] Step 12-3-3, each test cycle is 10 minutes;

[0151] Step 12-3-4, the rate limit function should be disabled during the test;

[0152] Step 12-3-5, the active power setting value starts from 100% and decreases in steps of 20%, and the operation time of each setting value is 2 minutes;

[0153] Step 12-3-6, during the entire test process, the available active power output is at least 0.9pn; Step 12-3-7, measuring the active power at the output end of the grid-type wind turbine;

[0154] Step 12-3-8, the acquired active power output is read from the grid-type wind turbine control system. If it is not easy to read from the grid-type wind turbine control system, an approximate value can be obtained by referring to the power curve of the grid-type wind turbine based on the measured wind speed;

[0155] The damping control test in step 13 comprises the following steps:

[0156] Step 13-1, adjust the grid-type fan to operate at 50% pn;

[0157] Step 13-2, adjust the damping coefficient of the grid-type fan to the minimum within the allowable range provided by the manufacturer;

[0158] Step 13-3, perform power step at ±10% pn and continue running for 30 seconds;

[0159] Step 13-4, recording the power and frequency curves of the grid-connected wind turbines;

[0160] Step 13-5, adjusting the damping coefficient of the grid-type fan to the middle value and the maximum value of the damping coefficient range provided by the manufacturer;

[0161] Step 13-6, compare the three test result curves to verify the effect and function of the damping control;

[0162] Step 13-7, adjust the grid-type fan to operate at 50% pn, and repeat steps (13-2) to (13-6);

[0163] The overload capacity test in step 14 may be performed by any one or more of the following steps:

[0164] Step 14-1, 1.1 times overload test, adjust the grid-type wind turbine to the hot standby state, set the reactive power value corresponding to 1.1pn under the load state of the grid-type wind turbine, run it continuously for 10 minutes, measure the sequential power at the grid-type wind turbine connection point, take the average power value every 0.2s as one point, and record the measured data;

[0165] Step 14-2, 1.2 times overload test, adjust the grid-type wind turbine to the hot standby state, set the grid-type wind turbine to carry out the reactive power value corresponding to 1.2pn under the load state, run continuously for 2 minutes, measure the sequential power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, and record the measured data;

[0166] Step 14-3, 1.5 times overload test, adjust the grid-type wind turbine to the hot standby state, set the reactive power value corresponding to 1.5pn under the load state of the grid-type wind turbine, run continuously for 30s, measure the sequential power at the grid-type wind turbine connection point, take the average power value every 0.2s as one point, and record the measured data;

[0167] Step 14-4, adjust the grid-type wind turbine to the hot standby state, set the grid-type wind turbine under load state, simulate the three-phase symmetrical fault of the line through the power grid simulation device to make the voltage drop to 0.2Un, and last for 10s, measure the timing power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, record the measured data, and verify whether the total current of the grid-type wind turbine can reach 3 times the rated current and last for 10s.

[0168] Preferably, the multi-machine coordinated control test method of the grid-type wind turbine verifies whether the multiple grid-type wind turbines meet the requirements of low and high voltage cascading fault ride-through, and performs a grid-type characteristic test on the multiple grid-type wind turbines.

[0169] Preferably, the grid-connected wind farm test method performs any one or more of the following steps:

[0170] Step S1, active power control test, includes the following steps:

[0171] Step S1-1, power increase test;

[0172] Step S1-1-1, setting the active power of the grid-connected wind farm to 0;

[0173] Step S1-1-2, adjust the active power setting value step by step to 0, -0.25pn, -0.5pn, -0.75pn, -pn, -0.75pn, -0.5pn, -0.25pn, 0, each power setting value runs continuously for 1 minute, and record the measured data;

[0174] Step S1-1-3, calculating the response time, regulation time and control deviation of the active power control in the remote regulation mode of the grid-connected wind farm, the response time calculation formula is:

[0175] T response =T start_adjust -T receive_command

[0176] Among them, T start_adjust It is the moment when the wind farm starts to adjust its output power;

[0177] T receive_command It is the moment when the wind farm receives the active power adjustment instruction;

[0178] The adjustment time calculation formula is: T regulation =T stable_output -T start_adjust

[0179] Among them, T stable_output It is the moment when the wind farm output power stabilizes near the new set value;

[0180] T start_adjust It is the moment when the wind farm starts to adjust its output power;

[0181] The control deviation calculation formula is: ΔP = P actual -P setpoint

[0182] Among them, P actual is the active power actually output by the wind farm;

[0183] P setpoint It is the active power required by the set value or dispatch instruction;

[0184] Step S1-1-4, change the power setting value continuous operation time to 10 minutes, and repeat steps (S1-1-2) to (S1-1-3);

[0185] Step S1-2, power reduction test, includes the following steps:

[0186] Step S1-2-1, setting the active power of the grid-connected wind farm to pn;

[0187] Step S1-2-2, adjust the active power setting value step by step to 0, 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0, each power setting value runs continuously for 1 minute, and record the measured data;

[0188] Step S1-2-3, calculating the response time, regulation time and control deviation of active power control;

[0189] Step S1-2-4, change the power setting value continuous operation time to 10 minutes, and repeat steps (S1-2-2) to (S1-2-3)

[0190] Step S2: automatic power generation control test, including the following steps:

[0191] Step S2-1, remote automatic power generation control test, set the grid-type wind farm to remote regulation mode, and set the active power to 0, manually issue AGC load instructions by the dispatcher, adjust the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0, and record the unit load situation;

[0192] Step S2-2, local automatic power generation control test, set the grid-type wind farm to the local adjustment mode, and set the active power to 0, the grid-type wind farm manually issues the AGC load command, and adjusts the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0, and record the unit load situation;

[0193] Step S3 reactive power regulation capability test includes the following steps:

[0194] S3-1, set the grid-type wind farm to no-load operation mode, with active power of pn;

[0195] S3-2, regulating the grid-connected wind farm to operate in the maximum inductive reactive power output working mode;

[0196] S3-3, measure the time series power at the grid connection point of the grid-connected wind farm, record the active power and reactive power for at least 30 seconds, take the average power value every 0.2 seconds as one point, and calculate the average active power and reactive power within the second 15 seconds;

[0197] S3-4, respectively adjusting the active power of the grid-type wind farm in the no-load operation mode to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn, 0, and repeating steps (S3-2) to (S3-3);

[0198] S3-5, adjusting the grid-connected wind farm to operate in a maximum capacitive reactive power output working mode, and repeating steps (S3-3) to (S3-4);

[0199] S3-6, with active power as the horizontal axis and reactive power as the vertical axis, draw the power envelope diagram of the grid-type wind farm;

[0200] S3-7, adjusting the grid-connected wind farm to operate in full load mode with active power pn, and repeating steps (S3-2) to (S3-6);

[0201] Step S4, power factor regulation capability test, includes the following steps:

[0202] Step S4-1, setting the grid-type wind farm in no-load operation mode, and adjusting the active power to four points of 0.25pn, 0.5pn, 0.75pn, and pn respectively;

[0203] Step S4-2, adjusting the power factor of the grid-type wind farm from leading 0.95 to lagging 0.95, with the adjustment amplitude not greater than 0.01, and measuring and recording the actual output power factor of the grid-type wind farm;

[0204] Step S4-3, setting the grid-type wind farm to a full-load operation mode, and adjusting the active power to four points of 0.25pn, 0.5pn, 0.75pn, and pn respectively;

[0205] Step S4-4, adjusting the power factor of the grid-type wind farm from leading 0.95 to lagging 0.95, with an adjustment range of no more than 0.01, measuring and recording the actual output power factor of the grid-type wind farm, and calculating the power factor accuracy, the power factor accuracy calculation formula is:

[0206]

[0207] Among them, PF 实际 is the actual measured power factor, PF 设定 is the set power factor;

[0208] Step S5, automatic voltage control test, check AGC interface information, and record; send rated power command to the grid-type wind farm, and run continuously for 2 minutes; use the data acquisition device to collect the current, voltage and power of the test point, and draw a real-time power curve; calculate the response time, adjustment time and control accuracy of active power, requiring the active power control accuracy to be within ±2% pn, the active power response time not exceeding 30s, and the adjustment time not exceeding 120s; send rated power command to the grid-type wind farm, and run continuously for 2 minutes; record the operating status of the grid-type wind farm after receiving the signal;

[0209] Step S6, power quality test, three-phase voltage RMS value during the test period; three-phase current RMS value during the test period; total voltage waveform distortion rate and 95% probability statistical value during the test period, the total distortion rate does not exceed 3%; total current waveform distortion rate and 95% probability statistical value during the test period, the total distortion rate does not exceed 3%; fundamental wave effective value and 2-25th voltage harmonic components and 95% probability statistical value during the test period; fundamental wave effective value and 2-25th current harmonic components and 95% probability statistical value during the test period; three-phase voltage unbalance at the measuring point during the test period, the unbalance does not exceed 2%; long-term flicker value of the voltage at the measuring point during the test period, the flicker value does not exceed 0.8;

[0210] Step S7, black start test; disconnect the switch of the entire station grid connection point, disconnect the load in the station, and close the transformer in the wind turbine collection line in the station; the background or cooperative control sends a black start command, and the wind turbine converter starts automatically with no load and zero voltage with the upper transformer; record the relevant waveforms, wait for the voltage to stabilize, and then record the line voltage effective value, frequency value and three-phase voltage imbalance.

[0211] Preferably, the grid-following and grid-building wind turbine joint operation test method and the grid-following and grid-building wind farm joint operation test method both perform any one or more of the following steps: active power control test; automatic power generation control test; reactive power control test; automatic voltage control test; primary frequency modulation test; grid-following and grid-building mode switching test.

[0212] Preferably, the following network to networking mode switching test includes a networking to following network mode switching test and a following network to networking mode switching test.

[0213] Preferably, the test of switching from network building to network following mode comprises the following steps:

[0214] Step a, adjusting the grid-forming wind turbine or wind farm to operate in the grid-forming mode;

[0215] Step b, adjusting the grid-type wind turbine or wind farm to operate at 50% pn for 3 minutes;

[0216] Step c, switching the grid-type wind turbine or wind farm mode to a grid-following operation mode;

[0217] Step d, recording the voltage, current and power of the grid-connected wind turbine or wind farm;

[0218] Step e, performing a phase angle jump tolerance test, with an angle of 15° to 30°;

[0219] Step f, recording the state of the grid-connected wind turbine or wind farm, and confirming whether the grid-connected wind turbine or wind farm has switched to a grid-following operation mode;

[0220] Step g, adjusting the grid-type wind turbine or wind farm to operate at 50% pn for 3 minutes continuously;

[0221] Step h, repeat steps (c) to (f).

[0222] Preferably, the test of switching from following the network to building the network mode comprises the following steps:

[0223] Step a1, adjusting the grid-connected wind farm to operate in a grid-following mode;

[0224] Step b1, adjusting the grid-type wind farm to operate at 50% pn for 3 minutes;

[0225] Step c1, switching the grid-building wind farm mode to the grid-building operation mode;

[0226] Step d1, recording the voltage, current and power of the grid-connected point of the grid-connected wind farm;

[0227] Step e1, performing a phase angle jump tolerance test at an angle of 15° to 30°;

[0228] Step f1, recording the state of the grid-forming wind farm, and confirming whether the grid-forming wind farm is switched to the grid-forming operation mode;

[0229] Step g1, adjusting the grid-type wind farm to operate at 50% pn for 3 minutes;

[0230] Step h1, repeat steps (c1) to (f1).

[0231] Compared with the prior art, the present invention has the following beneficial effects:

[0232] The present invention proposes a multi-level full-scenario grid-connected test method for grid-connected wind turbines. Due to the relative novelty of grid-connected wind turbine technology, there is currently a lack of a comprehensive and systematic test method to accurately evaluate its performance in various scenarios and working conditions. In view of the lack of a unified standard test method, test methods for four scenarios are proposed: a grid-connected wind turbine characteristic test method, a grid-connected wind farm test method, a grid-connected and grid-connected wind turbine joint operation test method, and a grid-connected and grid-connected wind farm joint operation test method; the necessity and advantages of these test methods are mainly reflected in the following aspects:

[0233] 1. Comprehensiveness: Through tests covering multiple levels and all scenarios, the performance of grid-connected wind farms under various working conditions can be comprehensively evaluated, including but not limited to the grid-connected characteristics of wind turbines, the grid-connected performance of wind farms, and the ability to operate in conjunction with traditional grid-connected wind turbines and wind farms;

[0234] 2. Technical development support: This test method can provide strong technical support for the further development of wind turbine technology, and provide data and experience for technological improvement and innovation through simulation and actual operation tests.

[0235] 3. Safety and stability: Through the grid-connected test of the grid-connected wind farm, the safety and stability of the wind farm grid connection can be ensured, which is crucial for the grid connection and consumption of new energy and the safe and stable operation of the power system. It helps to improve the stability and resilience of the power grid and reduce the impact of large-scale wind power access on the power grid;

[0236] 4. Standardization and normalization: By formulating standardized testing procedures and evaluation indicators, a scientific basis is provided for the technical research and development, product certification and market access of grid-type fans, which helps promote the standardized development of the industry;

[0237] In summary, the testing method of the present invention can not only meet the current needs of wind turbine grid-connected testing, but also provide a solid foundation for the further development and application of future wind power technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0238] Figure 1 It is a chain failure of low and high voltage of wind turbines;

[0239] Figure 2 Divide the low voltage ride through test items for wind turbines;

[0240] Figure 3 Classification of high voltage ride-through test items for wind turbines;

[0241] Figure 4 This is the no-load test content of the frequency regulation characteristics of wind turbines;

[0242] Figure 5 It is the test content of inertia response characteristics of wind turbines;

[0243] Figure 6 This is the test content for the adaptability of voltage phase mutation of wind turbines;

[0244] Figure 7 It is the test content of reactive power response to voltage jump;

[0245] Figure 8 is the reactive power setting value;

[0246] Fig. 9 is the active power setting value;

[0247] Fig.10 It is the allowable operating range of active power during the control of active power set value of wind turbine. DETAILED DESCRIPTION

[0248] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. All other embodiments obtained by ordinary technicians in the field without making creative work based on the embodiments of the present invention shall fall within the scope of protection of the present invention.

[0249] like Figures 1 to 10 As shown, it shows a specific embodiment of the present invention:

[0250] Example 1: Testing the networking characteristics of a single network-type wind turbine

[0251] Step 1: Low and high voltage cascading fault ride-through capability test;

[0252] It is required that when the voltage at the wind farm grid connection point drops to 20% of the nominal voltage (the voltage value is measured by the recording and broadcasting software), the wind turbines in the wind farm should ensure that they will not be disconnected from the grid and operate continuously for 10,000ms (use the recording and broadcasting software or the station monitoring system to check whether they are operating continuously for 10,000ms). When the voltage at the wind farm grid connection point rises to 130% of the nominal voltage (the voltage value is measured by the recording and broadcasting software), the wind turbines in the wind farm should ensure that they will not be disconnected from the grid and operate continuously for 10,000ms (use the recording and broadcasting software or the station monitoring system to check whether they are operating continuously for 10,000ms). Tests should be carried out under no-load conditions or load conditions respectively; verify whether the grid-connected wind turbines meet the requirements for low and high voltage cascading fault ride-through;

[0253] The test content includes the following sub-steps:

[0254] 1.1) Low and high voltage cascading fault ride-through no-load test;

[0255] a. Adjust the voltage fault generating device to simulate the low and high voltage chain faults of the three-phase voltage and two-phase voltage of the line. The voltage drop value should be (0.20±0.05)pu and the duration should be (625±20)ms; the voltage rise value should be (1.30±0.03)pu and the duration should be (500±20)ms. The voltage drop-voltage rise interval should be (0-10)ms. The chain fault waveform should be as shown in Table 1.

[0256] b. Record the voltage curve of the wind turbine grid connection point. (Use recording and playback software)

[0257] 1.2) Low and high voltage cascading fault ride-through load test;

[0258] a. Put the fan that was disconnected during the no-load test into operation and connect it to the test equipment;

[0259] b. Adjust the fan output power between 0.1pn and 0.3pn;

[0260] c. The voltage fault generating device is controlled to perform three-phase symmetrical voltage drop and rise. The voltage drop value should be (0.20±0.05)pu and the duration should be (625±20)ms; the voltage rise value should be (1.30±0.03)pu and the duration should be (500±20)ms. The voltage drop-voltage rise interval should be (0-10)ms. The chain fault waveform should be as shown in Table 1.

[0261] d. Record the waveforms of voltage and current at the wind turbine grid connection point (using recording software). The data should be recorded at least 10 seconds before the voltage drops and at least 15 seconds after the voltage returns to normal. Do this twice for each point.

[0262] e. Adjust the fan output power to 0.9pn; repeat (c) to (d);

[0263] f. Control the voltage fault generating device to drop and raise the two-phase voltage. The voltage drop value should be (0.20±0.05) pu and the duration should be (625±20) ms; the voltage increase value should be (1.30±0.03) pu and the duration should be (500±20) ms. The voltage drop-voltage increase interval should be (0-10) ms. The chain fault waveform should be as shown in Table 1. Repeat (d) to (e).

[0264] Step 2: Low voltage ride-through capability test;

[0265] It is required that when the voltage at the wind farm grid connection point drops to 20% of the nominal voltage (the voltage value is measured by the recording and broadcasting software), the wind turbines in the wind farm should be guaranteed to operate continuously for 10,000ms without disconnecting from the grid (use the recording and broadcasting software or the station monitoring system to check whether it is running continuously for 10,000ms). When the voltage at the wind farm grid connection point can be restored to 90% of the nominal voltage within 2s after the drop (the voltage value is measured by the recording and broadcasting software), the wind turbines in the wind farm should be guaranteed to operate continuously for 10,000ms without disconnecting from the grid (use the recording and broadcasting software or the station monitoring system to check whether it is running continuously for 10,000ms). Tests are carried out under no-load conditions or load conditions respectively; verify whether the grid-connected wind turbine meets the low voltage ride-through requirements; the test content includes the following sub-steps:

[0266] 2.1) Low voltage ride through no-load test;

[0267] a. Adjust the grid simulation device to simulate the three-phase voltage and two-phase voltage reduction of the line. When simulating three-phase voltage reduction, adjust the voltage amplitude to within the range of (0.20±0.05pu) for a test, and the duration should be within the range of (100000±20ms). The unit should be disconnected from the grid; when simulating two-phase voltage reduction, adjust the voltage amplitude to within the range of (0.20±0.05pu) for a test, and the duration should be within the range of (100000±20ms). The unit should be disconnected from the grid.

[0268] b. Record the voltage curve of the wind turbine grid connection point. (Use recording and playback software)

[0269] 2.2) Low voltage ride-through load test; (load test after no-load test is successful)

[0270] a. Put the fan that was disconnected during the no-load test into operation and connect it to the test equipment;

[0271] b. The fan output power is between 0.1pn and 0.3pn;

[0272] c. Control the power grid simulation device to perform three-phase symmetrical voltage reduction. First, adjust the voltage amplitude to within the range of (0.90±0.05) and conduct two tests. The duration should be within the range of (100000±20ms); then repeat the test in the voltage amplitude range of (0.75±0.05pu), (0.50±0.05pu), (0.35±0.05pu), and (0.20±0.05pu) in sequence.

[0273] d. Record the waveforms of voltage and current at the wind turbine grid connection point (using recording and broadcasting software). The data should be recorded at least 10 seconds before the voltage drops and at least 15 seconds after the voltage returns to normal. Do this twice for each point; do this twice for each point;

[0274] e. Adjust the fan power to be greater than 0.9pn; repeat (c) to (d);

[0275] f. Control the power grid simulation device to reduce the two-phase voltage. First, adjust the voltage amplitude to within the range of (0.90±0.05) and conduct two tests. The duration should be within the range of (100000±20ms). Then, adjust the voltage amplitude range to (0.75±0.05pu), (0.50±0.05pu), (0.35±0.05pu), and (0.20±0.05pu) in gradient and repeat (d) to (e).

[0276] Step 3 High voltage ride-through capability test

[0277] It is required that when the voltage at the wind farm grid connection point rises to 30% of the nominal voltage (using recording and broadcasting software), the wind turbines in the wind farm should ensure that they will not be disconnected from the grid and operate continuously for 10,000ms (using recording and broadcasting software or station monitoring system to check whether they are operating continuously for 10,000ms). When the voltage at the wind farm grid connection point can be restored to 110% of the nominal voltage within 10,000ms after the increase (using recording and broadcasting software), the wind turbines in the wind farm should ensure that they will not be disconnected from the grid and operate continuously. Tests are carried out under no-load conditions or load conditions respectively; verify whether the grid-connected wind turbines meet the high voltage ride-through requirements; the test content includes the following sub-steps:

[0278] 3.1) High voltage ride through no-load test;

[0279] a. Adjust the grid simulation device to simulate the increase of the three-phase voltage and two-phase voltage of the line. When simulating the increase of the three-phase voltage, adjust the voltage amplitude to the range of (1.20±0.03pu) for a test, and the duration should be within the range of (100000±20ms). The unit should be disconnected from the grid. Then set the voltage amplitude range to the range of (1.25±0.03pu) and (1.30±0.03pu) for another test, and the duration should be within the range of (10 When simulating two voltage reductions, adjust the voltage amplitude to (1.20±0.03pu) for a test, and the duration should be (100000±20ms). The unit should be disconnected from the grid, and then set the voltage amplitude range to (1.25±0.03pu) and (1.30±0.03pu) for another test, and the duration should be (100000±20ms).

[0280] b. Record the voltage curve of the wind turbine grid connection point.

[0281] 3.2) High voltage ride through load test;

[0282] a. Put the fan that was disconnected during the no-load test into operation and connect it to the test equipment;

[0283] b. Adjust the fan output power between 0.1pn-0.3pn;

[0284] c. Control the power grid simulation device to perform three-phase symmetrical voltage rise. First, adjust the voltage amplitude to within the range of (1.20±0.03pu) and conduct two tests. The duration should be within the range of (100000±20ms); then repeat the test in the voltage amplitude range according to the gradient of (1.25±0.03pu) and (1.30±0.03pu).

[0285] d. Record the waveforms of voltage and current at the wind turbine grid connection point. The data should be recorded at least 10 seconds before the voltage rises and at least 15 seconds after the voltage returns to normal. Do this twice for each point.

[0286] e. Adjust the fan output power to 0.9pn; repeat (c) to (d);

[0287] f. Control the power grid simulation device to raise the two-phase voltage. First, adjust the voltage amplitude to within the range of (1.20±0.03pu) and conduct two tests. The duration should be within the range of (100000±20ms). Then, adjust the voltage amplitude range to (1.25±0.03pu) and (1.30±0.03pu) in gradients and repeat the tests (d) to (e).

[0288] Step 4: Frequency deviation adaptability test;

[0289] The grid-type fans are required to maintain operation within the frequency deviation of 48.5Hz to 51.5Hz (monitored by recording and broadcasting software), the frequency adjustment step is 0.1Hz (operation instructions are given by equipment manufacturer personnel), and each step should last at least 5s (monitored by recording and broadcasting software); tests are carried out under no-load conditions or load conditions respectively; and the ability of grid-type fans to tolerate frequency anomalies is verified.

[0290] 4.1) Frequency adaptability no-load test

[0291] a. Adjust the output frequency of the grid adaptability detection device from 48Hz to 51.5Hz. The frequency adjustment step is 0.1Hz (operation instructions are given by the equipment manufacturer). Each step should last at least 5s (monitored by recording software). Record the actual frequency value and the corresponding adjustment parameters for each adjustment.

[0292] b. Adjust the output frequency of the test device from the rated frequency to 48Hz, 48.5Hz, 49Hz, 49.9Hz, 50.1Hz, 50.5Hz, 51Hz, and 51.5Hz respectively. Each frequency setting value should be maintained for at least 5s. Record the actual measured frequency value and the corresponding adjustment parameters for each adjustment.

[0293] 4.2) Frequency adaptability load test

[0294] a. The wind turbine operates normally and does not participate in system frequency modulation. During the test, the active power output of the wind turbine should be above 10% of the rated power (monitored by recording and broadcasting software). The test adopts the following steps:

[0295] (1) Keep the wind turbine in normal operation under rated voltage conditions, adjust the test device to gradually increase the frequency from the rated frequency in steps of 0.1Hz (monitored by recording software), and each step should last at least 20s. When the frequency rises to 51.5Hz, the test duration at this point should be no less than 30min. During the test, if the wind turbine is disconnected from the grid, the test duration and the time the wind turbine is disconnected from the grid need to be recorded.

[0296] (2) Keep the wind turbine in normal operation under rated voltage conditions, adjust the test device to gradually reduce the frequency from the rated frequency in steps of 0.1 Hz (monitored by recording software), and each step should last at least 20 seconds. When the frequency drops to 48 Hz, the test duration at this point should be no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid.

[0297] b. The wind turbine is operated under limited power and frequency modulation conditions. During the test, the active power output of the wind turbine should be above 20% of the rated power. The test adopts the following steps:

[0298] (1) Under rated voltage conditions, adjust the output frequency of the test device from the rated value to 48Hz, 48.5Hz, 49Hz, 49.9Hz, 50.1Hz, 50.5Hz, 51Hz, and 51.5Hz respectively. The frequency holding time should be no less than 30s. After the frequency returns to the rated value, the holding test time should be no less than 10s. During the test, record whether the wind turbine is disconnected from the grid.

[0299] (2) Under rated voltage conditions, set the output frequency of the test device one by one in the order of 48 Hz, 48.5 Hz, 49 Hz, 49.9 Hz, 50.1 Hz, 50.5 Hz, 51 Hz, and 51.5 Hz, and repeat process (a).

[0300] Step 5: One frequency modulation test;

[0301] The grid-type wind turbine is required to support a power response time of less than 0.5s (monitored by recording and broadcasting software), and can be flexibly adjusted according to the access to the power grid; the primary frequency modulation active power regulation deviation is not greater than 2% (calculated after monitoring by recording and broadcasting software, the calculation formula is regulation deviation = (actual value - command value / command value)); the test is carried out in the power range above 0.9pn and 0.2pn to 0.5pn (monitored by recording and broadcasting software), under load conditions or no-load conditions; verify the ability of the grid-type wind turbine to output primary frequency modulation active power when the grid frequency deviates; the test content includes the following sub-steps:

[0302] 5.1) One frequency modulation dead zone test;

[0303] a. Set the primary frequency modulation parameters of the grid-type fan (operation instructions are given by the equipment manufacturer), and connect the grid-type fan and related testing and measuring equipment;

[0304] b. Adjust the grid-type fan to operate in no-load mode (operation instructions are given by the equipment manufacturer's personnel and monitored by recording and broadcasting software);

[0305] c. Gradually increase the frequency value of the grid connection point with a step size of 0.01Hz until the active power starts to change regularly. Each frequency setting value runs for 5s, and the output frequency value at the time when the active power changes regularly during the frequency disturbance process is recorded; (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0306] d. Gradually reduce the frequency value of the grid connection point with a step size of 0.01Hz until the active power starts to change regularly. Run each frequency setting value for 5s and record the output frequency value at the time when the active power changes regularly during the frequency disturbance process; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0307] e. Repeat c) to d);

[0308] f. Adjust the grid-type fans to operate in pn constant power load mode;

[0309] g. Adjust the grid-type fans to operate at no less than 20% pn;

[0310] h. Repeat c) to e).

[0311] 5.2) Frequency step disturbance test;

[0312] a. Connect the data acquisition device (recording and broadcasting software) to the voltage transformer (PT) and current transformer (CT) at the test point, and connect the frequency signal generator to the grid-type wind turbine monitoring system;

[0313] b. Adjust the grid-type fan to operate in no-load mode; (operation instructions are given by the equipment manufacturer's personnel and monitored by recording and broadcasting software);

[0314] c. The grid-type wind turbine is tested in the unlimited power and limited power operating states respectively, and the active power is tested according to the grid-type wind turbine operating state and power range; (monitored by recording and broadcasting software)

[0315] d. Use the frequency signal generator to output a frequency step disturbance signal from 50Hz to 50.15Hz, 50Hz to 50.205Hz, 50Hz to 49.85Hz, and 50Hz to 49.80Hz. Test each operating condition twice;

[0316] e. Record voltage, current, frequency and power values ​​during the test (monitored by recording and broadcasting software);

[0317] f. Calculate the primary frequency modulation response lag time, rise time, adjustment time and active power control deviation;

[0318] g. Adjust the grid-type fan to operate in pn constant power no-load mode;

[0319] h. Use the frequency signal generator to output a frequency step disturbance signal from 50Hz to 50.15Hz, 50Hz to 50.205Hz, 50Hz to 49.85Hz, and 50Hz to 49.80Hz. Test each operating condition twice;

[0320] i. Record voltage, current, frequency and power values ​​during the test (monitored by recording and broadcasting software);

[0321] j. Calculate the primary frequency modulation response lag time, rise time, regulation time and active power control deviation.

[0322] (The response lag time is the time required for the actual output active power change of the fan to reach 10% of the difference between the active power target value and the initial value, starting from the time when the fan frequency increases or decreases more than one frequency modulation dead zone;

[0323] Rise time refers to the time required for the actual output active power change of the fan to reach 90% of the difference between the active power target value and the initial value, starting from the time when the fan frequency increases or decreases by more than one frequency modulation zone;

[0324] The adjustment time is the shortest time from when the fan frequency increases or decreases more than one frequency regulation dead zone, and the absolute value of the difference between the fan's actual output active power and the active target value never exceeds the allowable deviation;

[0325] 5.3) One-time frequency modulation and amplitude limiting test;

[0326] a. Connect the data acquisition device (recording and broadcasting software) to the voltage transformer (PT) and current transformer (CT) at the test point, and connect the frequency signal generator to the grid-type wind turbine monitoring system;

[0327] b. Adjust the grid-type fan to operate in no-load mode; (monitored by recording and broadcasting software)

[0328] c. Set the frequency value of the grid connection point to gradually increase in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s. The maximum frequency difference step should not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process; (operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software);

[0329] d. Set the frequency value of the grid connection point to be gradually reduced in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s. The maximum frequency difference step should not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process; (operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software);

[0330] e. Adjust the grid-type fan to operate in pn constant power no-load mode;

[0331] f. Adjust the grid-type fan to operate at 20% pn (operation instructions are given by the equipment manufacturer's personnel and monitored by recording and broadcasting software);

[0332] g. Repeat steps c) to f).

[0333] Step 6 Inertia response test:

[0334] The maximum value of the inertia time constant of the grid-type wind turbine is required to be no less than 20 seconds, the active power change ΔPI should not be less than 10% pn, the response time should not be greater than 0.5s, the error between the actual active power and the active power command should not exceed ±2% pn (error = command value - actual value / command value), and it can be flexibly adjusted according to the needs of the access system; the test is carried out in the power range above 0.9pn and 0.2pn to 0.5pn, under no-load conditions or load conditions; verify the ability of the grid-type wind turbine to output active inertia response when the grid frequency deviates; (monitored by recording and broadcasting software)

[0335] 6.1) Inertia response no-load test

[0336] Adjust the output frequency of the grid adaptability detection device from 50Hz, and change it to 51.5Hz at a rate of change of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, keep it for no less than 10s, and then restore it to 50Hz at the same rate of change; repeat the above process, adjust the frequency from 50Hz to 48Hz, and then restore it to 50Hz, and record the actual frequency value and the corresponding adjustment parameters during each adjustment. (Monitoring with recording software)

[0337] 6.2) Inertia response load test

[0338] a. Maintain normal operation of the wind turbine under rated voltage conditions. Adjust the output frequency of the test device from 50Hz to 51.5Hz at a rate of change of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, maintain the test time for no less than 10s. After the frequency returns to the rated value at the same frequency change rate, maintain the test time for no less than 10s. During the test, record whether the wind turbine is off the grid. (Monitor with recording software)

[0339] b. Maintain normal operation of the wind turbine under rated voltage conditions. Adjust the output frequency of the test device from 50Hz to 48Hz at a rate of change of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, maintain the test time for no less than 10s. After the frequency is restored to the rated value at the same rate of change, maintain the test time for no less than 10s. During the test, record whether the wind turbine is off the grid. (Monitor with recording software)

[0340] Step 7: Voltage deviation adaptability test;

[0341] The grid-type wind turbine is required to maintain normal operation of the wind turbine set under rated frequency conditions (monitored by recording and broadcasting software), and the test device is adjusted to gradually reduce the voltage from the rated voltage in steps of 1% UN and 2% UN. Each step should last at least 20 seconds (operation instructions are given by the equipment manufacturer's personnel and monitored by recording and broadcasting software); the test is carried out under no-load conditions or load conditions respectively; the adaptability of the grid-type wind turbine to the grid voltage deviation is verified;

[0342] 7.1) Voltage deviation adaptability no-load test

[0343] When the wind turbine is disconnected from the grid, adjust the output voltage of the grid adaptability detection device from 0.9pu to 1.1pu (operation instructions are given by the equipment manufacturer's personnel and monitored by recording and broadcasting software). The voltage adjustment step is 1% and 2% of the rated voltage respectively. Each step should last at least 5s. Record the actual voltage measured value and the corresponding adjustment parameters for each adjustment.

[0344] 7.2) Voltage deviation adaptability load test

[0345] a. Keep the wind turbine running normally under rated frequency conditions, adjust the test device to gradually increase the voltage from the rated voltage in steps of 1% and 2% of the rated voltage, and each step should last at least 20 seconds. When the voltage rises to 1.10pu, the test duration at this point should be no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid. (Operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0346] b. Keep the wind turbine running normally under rated frequency conditions, adjust the test device to gradually reduce the voltage from the rated voltage by 1% and 2% of the rated voltage, and each step should last at least 20 seconds. When the voltage drops to 0.90pu, the test duration at this point should be no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid. (Operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0347] Step 8 Power quality adaptability test

[0348] The sum of the absolute values ​​of the positive and negative deviations of the grid-connected point voltage is required to be no more than 10% of the nominal voltage (monitored by recording and broadcasting software). The test is carried out under no-load or load conditions respectively; the power quality of the grid-connected wind turbine is verified; the test content includes the following sub-steps:

[0349] 8.1) Harmonic voltage adaptability

[0350] 8.1.1) Harmonic voltage adaptability no-load test

[0351] a. The amplitude of broadband voltage disturbance is 0.03pu;

[0352] b. The wideband voltage disturbance frequency range is 0.1Hz~10000Hz;

[0353] c. Inject a voltage disturbance of a frequency (the disturbance frequency range is shown in d)) each time; (operation instructions are given by the equipment manufacturer's personnel and monitored by recording and broadcasting software)

[0354] d. When the disturbance frequency is 0.1~1Hz, the frequency change step is 0.1Hz; when the disturbance frequency is 1~100Hz, the frequency change step is 1Hz; when the disturbance frequency is 100~10000Hz, the frequency change step is 5Hz, and the duration is 0.5min.

[0355] 8.1.2) Harmonic voltage adaptability no-load test

[0356] a. Maintain normal operation of the unit under rated voltage and rated frequency conditions.

[0357] b. Set the adjustment parameter to the 5Hz inter-harmonic voltage content rate setting value during no-load test. If the wind turbine is not disconnected from the grid after the corresponding adjustment parameter lasts for 2 minutes, stop the test; if the wind turbine is disconnected from the grid, record the test duration and the wind turbine disconnection time. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0358] c. The interharmonic voltage adaptability test method is the same as b).

[0359] d. Restore the voltage and frequency to the rated conditions and keep the unit running normally. Set the adjustment parameters to the adjustment parameters corresponding to the set value of the third harmonic content rate during the no-load test. If the wind turbine is not disconnected from the grid after 2 minutes, stop the test; if the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid. (Operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0360] e. The odd harmonic voltage adaptability test method is the same as d).

[0361] f. Restore the voltage and frequency to the rated conditions and keep the unit running normally. Set the adjustment parameters to the adjustment parameters corresponding to the setting value of the second harmonic content rate during the no-load test. If the wind turbine is not disconnected from the grid after 2 minutes, stop the test; if the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0362] g. The test method for even-order harmonic voltage adaptability is the same as f).

[0363] 8.2) Adaptability to three-phase voltage imbalance

[0364] 8.2.1) Three-phase voltage unbalance adaptability no-load test

[0365] Restore the grid adaptability detection device to maintain rated output voltage and frequency, set and adjust the three-phase voltage imbalance to 2% and 4% respectively, continue to operate for 30 minutes and 1 minute, and record the corresponding three-phase imbalance voltage value. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0366] 8.2.2) Three-phase voltage unbalanced adaptive load test

[0367] The output voltage and frequency of the grid adaptability detection device are restored to the rated value. The wind turbine is set to unity power factor control. During the test, the active power output of the wind turbine should be above 50% of the rated power. The three-phase voltage imbalance is set to 2% and 4% respectively, and the operation lasts for 30 minutes and 1 minute, and the corresponding three-phase imbalance voltage value is recorded. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0368] 8.3) Flicker adaptability

[0369] 8.3.1) Flicker adaptability no-load test

[0370] Restore the grid adaptability detection device to maintain rated output voltage and frequency, set and adjust the three-phase voltage imbalance to 2% and 4% respectively, continue to operate for 30 minutes and 1 minute, and record the corresponding three-phase imbalance voltage value. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0371] 8.3.2) Flicker adaptability load test

[0372] The wind turbine is set to unity power factor control. During the test, the active power output of the wind turbine should be above 30% of the rated power. Maintain normal operation of the unit under rated voltage and rated frequency conditions, set the same adjustment parameters as the no-load test, and stop the test if the wind turbine is not disconnected from the grid after 10 minutes; if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid. (Operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0373] Step 9: Voltage phase mutation adaptability test;

[0374] It is required that the amplitude and phase angle of the voltage at the terminal of the grid-connected converter of the grid-connected wind turbine should have a certain maintenance capability in the steady-state and transient process, be able to share the unbalanced power of the grid, and the power response time should be no more than 5ms (monitored by recording and broadcasting software); the test should be carried out in the power range of 20% pn to 80% pn, under no-load condition or load condition; the ability of the grid-connected wind turbine to quickly inject active power when the voltage phase suddenly changes;

[0375] (The power response time is the time required for the actual output active power change of the grid-type wind turbine to reach 10% of the difference between the active power target value and the initial value)

[0376] 9.1) Voltage phase mutation adaptability no-load test

[0377] When the wind turbine is disconnected from the grid, when the power supply voltage deviation at the test point is within the limit of 0.9pu to 1.1pu, use the test device to generate the required voltage phase mutation at the test point. Set the voltage phase mutation angle to 5°, 30°, -5°, and -50° respectively, and keep running without disconnection for 30 seconds. If the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0378] 9.2) Voltage phase mutation adaptability load test

[0379] During the test, the active power output of the wind turbine should be above 30% of the rated power. When the supply voltage deviation at the test point is within the limit of 0.9pu to 1.1pu, the test device is used to generate the required voltage phase mutation at the test point. The voltage phase mutation angles are set to 5°, 30°, -5°, and -50°, respectively. The wind turbine should be kept running without disconnection for 30 seconds. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded. (Operation instructions are issued by the equipment manufacturer and monitored by recording and broadcasting software)

[0380] Step 10) Test the switching between network following and network building modes

[0381] Connect the grid-forming wind turbine to the public power grid, adjust all parameters to normal working conditions, and conduct tests under no-load or load conditions; verify the ability of the grid-forming wind turbine to switch between the grid-following mode and the grid-forming mode;

[0382] 1.10.1) Test the switching from network building mode to network following mode;

[0383] a. Adjust the grid-type fan to operate in grid-type mode;

[0384] b. Adjust the grid-type fan to run at 50% PN for 3 minutes (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software);

[0385] c. Switch the grid-type fan mode to the grid-following operation mode;

[0386] d. Record the voltage, current and power of the grid-connected wind turbine (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software); e. Conduct phase angle jump tolerance test (the angle range can be selected between 15°-30°);

[0387] f. Record the status of the grid-forming wind turbine and confirm whether the grid-forming wind turbine has switched to the grid-following operation mode; (Based on the monitoring file of the recording and broadcasting software, the phase angle jump in the grid-forming control mode will cause fluctuations in active power, reactive power and current, while the phase angle jump in the grid-following control mode will not cause fluctuations in active power, reactive power and current)

[0388] g. Adjust the grid-type fan to run at 50% PN for 3 minutes continuously; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software);

[0389] h. Repeat steps c) to f).

[0390] 1.10.2) Test the switching mode from following network to building network.

[0391] a. Adjust the grid-type fan to operate in the grid-following mode;

[0392] b. Adjust the grid-type fan to run at 50% PN for 3 minutes continuously; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software);

[0393] c. Switch the grid-type fan mode to the grid-type operation mode;

[0394] d. Record the voltage, current and power of the grid-connected wind turbine (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software);

[0395] e. Conduct phase angle jump tolerance test (the angle range can be selected between 15°-30°);

[0396] f. Record the status of the grid-type wind turbine and confirm whether the grid-type wind turbine has switched to the grid-type operation mode; (According to the monitoring file of the recording and broadcasting software, the phase angle jump in the grid-type control mode will cause fluctuations in active power, reactive power and current, while the phase angle jump in the grid-following control mode will not cause fluctuations in active power, reactive power and current)

[0397] g. Adjust the grid-type fan to run at 50% PN for 3 minutes continuously; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software);

[0398] h. Repeat steps c) to f).

[0399] Step 11 Reactive power regulation capability test

[0400] It is required that the steady-state reactive power control deviation of the constant reactive power control of the grid-type wind turbine should not exceed ±2% pn (deviation = command value - actual value / command value), and the reactive power step response time should not exceed 100ms (the time when the wind turbine power reaches 90% of the rated power pn for the first time since receiving the control signal). Tests are carried out in the reactive power set value control mode, no-load and load conditions (operation instructions are given by the equipment manufacturer personnel and monitored by recording and broadcasting software) to verify the reactive power regulation capability of the grid-type wind turbine. The test content includes the following sub-steps:

[0401] 11.1) Control-based reactive power response capability Maximum inductive reactive power and maximum capacitive reactive power test

[0402] a. Only collect data under continuous operation;

[0403] b. Set the active power of the wind turbine power station to pn; adjust the wind turbine power station to operate in the working mode of outputting the maximum inductive reactive power;

[0404] c. Adjust the charging active power of the wind power station to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn and 0 respectively, and measure the active power and reactive power at the output end of the grid-type wind turbine (monitored by recording and broadcasting software);

[0405] d. For each 10% rated power interval, at least 30 1-minute active power and reactive power time series measurement data should be collected;

[0406] e. In each 1-minute time period, the sampled data is converted into a 1-minute average using the block averaging method;

[0407] f. Arrange the 1-minute average values ​​according to the interval method, and indicate in a table the corresponding average interval values ​​of reactive power when the active power output is 0%, 10%, ..., 90%, and 100% of the rated power. Here, 0%, 10%, ..., 90%, and 100% are the midpoints of the rated power interval;

[0408] j. Adjust the wind turbine power station to operate in the maximum inductive reactive power output working mode, and repeat (c) to (f).

[0409] 11.2) Reactive power response capability based on control Capability test of reactive power setpoint control mode operation

[0410] a. Only collect data under continuous operation;

[0411] b. Set the active power of the wind turbine power station to pn, adjust the charging active power of the wind turbine power station to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn and 0 respectively, and measure the active power and reactive power at the output end of the grid-type wind turbine (monitored by recording and broadcasting software);

[0412] c. For each 10% rated power interval, at least 30 1-minute active power and reactive power time series measurement data should be collected;

[0413] d. In each 1-minute time period, the sampled data is converted into a 1-minute average using the block averaging method;

[0414] e. The 1-minute average value is sorted according to the interval method, and the reactive power setting value control ability test results are presented in the form of a chart, and the table shows the corresponding reactive power average interval values ​​when the active power output is 0%, 10%, ..., 90%, and 100% of the rated power. Here, 0%, 10%, ..., 90%, and 100% are the midpoints of the rated power interval.

[0415] 11.3) Reactive power response capability based on control Reactive power step change test

[0416] a. Only collect data under continuous operation;

[0417] b. Measure active power and reactive power at the output end of the grid-type wind turbine;

[0418] c. The active power output is about 50% of the rated power;

[0419] d. The active power measurement result is the average value of 1 minute;

[0420] e. The reactive power test result is the average value of 0.2s;

[0421] f. The reactive power regulation should last for no less than 2 minutes when the capacitive reactive power is fully generated; and should last for no less than 2 minutes when the inductive reactive power is fully generated;

[0422] g. The reactive power setting value control capability test results are presented in a chart. The results in the chart should be 0.2s test data and the corresponding reactive power setting value.

[0423] 11.4) Voltage jump reactive power response no-load test

[0424] a. Adjust the power grid simulation device, and the duration of the simulated line three-phase voltage rising to 1.1pu should not be less than 625ms; adjust the power grid simulation device, and the duration of the simulated line three-phase voltage dropping to 0.9pu should not be less than 625ms;

[0425] b. Record the voltage curve of the grid-connected wind turbine (monitored by recording and broadcasting software)

[0426] 11.5) Voltage jump reactive power response load test

[0427] a. Connect the grid-connected wind turbine that was disconnected during the no-load test to the grid for operation;

[0428] b. Adjust the output power of the grid-type fan to between 0.1pn and 0.3pn;

[0429] c. Control the power grid simulation device to perform symmetrical three-phase voltage disturbance; the duration of the simulated line three-phase voltage rising to 1.1pu should not be less than 30 minutes; adjust the power grid simulation device, and the duration of the simulated line three-phase voltage dropping to 0.9pu should not be less than 30 minutes;

[0430] d. Record the waveforms of voltage and current at the grid-connected points of the grid-connected wind turbines. The data should be recorded at least 10 seconds before the voltage disturbance and 6 seconds after the voltage returns to normal. Each point should be recorded twice; (Monitored by recording and broadcasting software)

[0431] e. Adjust the grid-type fan output power to 0.9pn, and repeat steps c) to d);

[0432] Step 12 Active power regulation capability test

[0433] It is required that the maximum deviation allowed for the active power set value control of the grid-type wind turbine shall not exceed 5% pn (deviation = command value - actual value / command value). When the set value change is less than 20% pn, the response time shall not exceed 10s (the time when the power of the wind turbine reaches 90% of the rated power pn for the first time since the control signal is received); when the set value change reaches 80% pn, the response time shall not exceed 30s (the time when the power of the wind turbine reaches 90% of the rated power pn for the first time since the control signal is received); tests shall be carried out under the conditions of maximum measured power, rate of increase limit, and set value control to verify the active power regulation capability of the grid-type wind turbine;

[0434] 12.1) Active power regulation capability maximum measurement power test

[0435] a. Only collect data under continuous operation;

[0436] b. Measure the active power at the output end of the grid-type wind turbine (monitored by recording and broadcasting software)

[0437] c. Cut-in wind speed is between 15m / s and at least 5 10-min time series of power measurement data should be collected for each 1m / s wind speed interval;

[0438] d. The wind speed measurement result is the average value of 10 minutes;

[0439] e. Use block averaging to convert the power measurement data into 0.2s average value and 1min average value within the measurement period;

[0440] f. When measuring current, the full scale range should be twice the rated current of the grid-type fan;

[0441] 12.2) Active power regulation capability rate limit test

[0442] a. The grid-type fan starts from the shutdown state;

[0443] b. The power increase rate is set to 10% rated power / min (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software); c. The grid-connected wind turbine is tested for 10 minutes after being connected to the grid;

[0444] d. During the entire test process, the available active power output should be at least 50% of the rated power;

[0445] e. Measure the active power at the output end of the grid-type wind turbine;

[0446] f. The test results in the report should be the average value of active power every 0.2s.

[0447] 12.3) Active power regulation capability set value control test

[0448] a. Within the first 24 hours when the wind farm predicts that the average wind speed can meet the output power of the wind farm to reach more than 80% of the rated capacity of the wind farm, inquire about the power forecast results of surrounding wind farms. If the forecast results are close, report the estimated start time of the test to the dispatcher and prepare to start the test;

[0449] b. On-site personnel pay close attention to the medium and ultra-short-term forecasts of the wind power prediction system of the wind farm. If the forecast wind speed increases, they will formally apply to the dispatcher to start the test. During the test, the active control mode of the wind farm under test is adjusted to the local control mode, and the wind farm will automatically issue the active output command of the self-synchronous voltage source of the grid-connected wind turbine.

[0450] c. Each test cycle is 10 minutes;

[0451] d. To obtain the fastest possible response, the rate limit function should be disabled during the test;

[0452] e. The active power setting value starts from 100% and decreases in steps of 20%. The operation time of each setting value is 2 minutes; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0453] f. During the entire test process, the available active power output should be at least 0.9pn (monitored by recording and broadcasting software);

[0454] g. Measure the active power at the output end of the grid-type wind turbine;

[0455] h. The available active power output can be read from the grid-type wind turbine control system. If reading from the grid-type wind turbine control system is not easy to achieve, an approximate value can be obtained by referring to the power curve of the grid-type wind turbine based on the measured wind speed.

[0456] Step 13 Damping Control Test

[0457] The grid-type wind turbine is required to have an autonomous damping suppression function. When the system has a low-frequency oscillation of 0.2Hz to 2.5Hz, and the frequency oscillation amplitude of the grid-connected point is greater than 0.003Hz (monitored by recording and broadcasting software), the wind turbine should be able to suppress the oscillation, and the maximum value of the active power change ΔPD should not be less than 10%pn and not higher than 30%pn. The response time should not be greater than 500ms (the time when the wind turbine power reaches 90% of the rated power pn for the first time since receiving the control signal, monitored by recording and broadcasting software). Tests are carried out under load conditions in the power ranges of 0.9pn to 1.0pn and above and 0.2pn to 0.5pn respectively; verify the damping control ability of the grid-type wind turbine on the system when the grid has low-frequency oscillations;

[0458] a. Adjust the grid-type fan to operate at 50% PN; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0459] b. Adjust the damping coefficient of the grid-type fan to the minimum within the allowable range provided by the manufacturer;

[0460] c. Perform power step at ±10% pn and continue running for 30 seconds; (operation instructions are given by the equipment manufacturer and monitored by recording and broadcasting software)

[0461] d. Record the power and frequency curves of the grid-connected wind turbines;

[0462] e. Adjust the damping coefficient of the grid-type fan to the middle and maximum values ​​of the damping coefficient range provided by the manufacturer.

[0463] f. Compare the three test result curves to verify the effect and function of damping control. (When the damping coefficient increases, the corresponding active power fluctuation amplitude decreases and the oscillation period becomes shorter.)

[0464] g. Adjust the mesh fan to run at 50% pn and repeat steps b) to f);

[0465] Step 14 Overload capacity test

[0466] It is required that the AC side current of the grid-type wind turbine should be able to operate continuously for a long time at 110% of the rated current (monitored by recording and broadcasting software), the continuous operation time should be no less than 2 minutes at 120% of the rated current (monitored by recording and broadcasting software), and the continuous operation time should be no less than 1 minute at 150% of the rated current (monitored by recording and broadcasting software), and it should have a short-term overload capacity of 300% of the rated current for 10 seconds (monitored by recording and broadcasting software); connect the wind turbine to the public power grid, adjust all parameters to normal working conditions, and conduct tests under load conditions; verify the overload capacity of the grid-type wind turbine;

[0467] a) 1.1 times overload test, adjust the grid-type wind turbine to hot standby state, set the reactive power value corresponding to 1.1pn under the grid-type wind turbine load state, run continuously for 10 minutes, measure the sequential power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, and record the measured data. (Operation instructions are given by the equipment manufacturer personnel, and monitoring is performed using recording and broadcasting software)

[0468] b) 1.2 times overload test, adjust the grid-type wind turbine to hot standby state, set the reactive power value corresponding to 1.2pn under the load state of the grid-type wind turbine, run continuously for 2 minutes, measure the time sequence power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, and record the measured data. (Operation instructions are given by the equipment manufacturer personnel, and monitoring is carried out using recording and broadcasting software)

[0469] c) 1.5 times overload test, adjust the grid-type wind turbine to hot standby state, set the reactive power value corresponding to 1.5pn under the load state of the grid-type wind turbine, run continuously for 30s, measure the time sequence power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, and record the measured data. (Operation instructions are given by the equipment manufacturer personnel, and monitoring is carried out using recording and broadcasting software)

[0470] d) Adjust the grid-type wind turbine to the hot standby state, set the grid-type wind turbine to load state, simulate the three-phase symmetrical fault of the line through the power grid simulation device to make the voltage drop to 0.2Un, last for 10s, measure the time sequence power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, record the measured data, and verify whether the total current of the grid-type wind turbine can reach 3 times the rated current and last for 10s. (The equipment manufacturer issues the operation instruction and the recording and broadcasting software is used for monitoring)

[0471] Example 2: Testing the grid characteristics of multiple grid-type wind turbines

[0472] Step 1: Low and high voltage cascading fault ride-through capability test;

[0473] It is required that when the voltage at the wind farm grid connection point drops to 20% of the nominal voltage (the voltage value is measured by the recording and broadcasting software), the multiple grid-type wind turbines in the wind farm should ensure that they will not be disconnected from the grid and operate continuously for 10,000ms (use the recording and broadcasting software or the station monitoring system to check whether they are operating continuously for 10,000ms). When the voltage at the wind farm grid connection point rises to 130% of the nominal voltage (the voltage value is measured by the recording and broadcasting software), the multiple grid-type wind turbines in the wind farm should ensure that they will not be disconnected from the grid and operate continuously for 10,000ms (use the recording and broadcasting software or the station monitoring system to check whether they are operating continuously for 10,000ms). Tests should be carried out under no-load conditions or load conditions respectively; verify whether multiple grid-type wind turbines meet the requirements for low and high voltage cascading fault ride-through;

[0474] The test content is the same as the test steps of the first embodiment, and multiple grid-type fans are tested simultaneously.

[0475] Example 3: Basic grid-connected performance test for grid-connected wind farms

[0476] Step 1: Active power control test;

[0477] The grid-type wind farm is required to be connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind farm output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind farm output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power, and tests are carried out respectively; verify that the active power control accuracy of the grid-type wind farm is within ±2%pn, the active power command response does not exceed 30s, and the adjustment time does not exceed 120s; the test content includes the following sub-steps:

[0478] 3.1.1) Power test;

[0479] a. Set the active power of the grid-connected wind farm to 0;

[0480] b. Adjust the active power setting value step by step to 0, -0.25pn, -0.5pn, -0.75pn, -pn, -0.75pn, -0.5pn, -0.25pn, 0. Each power setting value runs continuously for 1 minute and records the measured data;

[0481] c. Calculate the response time, regulation time and control deviation of active power control in remote regulation mode of grid-connected wind farms.

[0482] Active power control response time calculation formula: Tresponse = Tstart_adjust - Treceive_command

[0483] Where: Tstart_adjust is the time when the wind farm starts to adjust the output power;

[0484] Treceive_command is the moment when the wind farm receives the active power adjustment command;

[0485] Adjustment time calculation formula: Tregulation = Tstable_output-Tstart_adjust

[0486] Where: Tstable_output is the moment when the wind farm output power stabilizes near the new set value;

[0487] Tstart_adjust is the moment when the wind farm starts to adjust its output power;

[0488] Deviation calculation formula: ΔP = Pactual - Psetpoint

[0489] Where: Pactual is the active power actually output by the wind farm;

[0490] Psetpoint is the active power required by the set value or dispatch instruction;

[0491] d. Change the power setting value to continuous operation time of 10 minutes and repeat steps b) to c)

[0492] 3.1.2) Power reduction test;

[0493] a. Set the active power of the grid-connected wind farm to pn;

[0494] b. Adjust the active power setting value step by step to 0, 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0. Each power setting value runs continuously for 1 minute and records the measured data;

[0495] c. Calculate the response time, regulation time and control deviation of active power control;

[0496] d. Change the power setting value to continuous operation time of 10 minutes and repeat steps b) to c)

[0497] Step 2: Automatic power generation control test;

[0498] The grid-type wind farm is required to receive and respond to the sent AGC instructions; the grid-type wind farm is connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind farm output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind farm output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power, and tests are carried out respectively; verify that the active power control accuracy of the grid-type wind farm is within ±2%pn, the active power instruction response does not exceed 30s, and the adjustment time does not exceed 120s; the test content includes the following sub-steps:

[0499] 3.2.1) Remote automatic power generation control test;

[0500] a. Set the grid-connected wind farm to remote regulation mode and set the active power to 0;

[0501] b. The dispatcher manually issues AGC load instructions to adjust the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0;

[0502] c. Record the load of the unit;

[0503] 3.2.2) Local automatic power generation control test;

[0504] a. Set the grid-type wind farm to local regulation mode and set the active power to 0;

[0505] b. The grid-type wind farm manually issues AGC load instructions to adjust the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0;

[0506] c. Record the load of the unit;

[0507] Step 3: reactive power regulation capability test;

[0508] The grid-type wind farm is required to be connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind farm output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind farm output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power. Tests are carried out respectively; verify the reactive power regulation capability of the grid-type wind farm in the grid control mode. The specific steps of the test method are as follows:

[0509] a. Set the grid-type wind farm to no-load operation mode, with active power of pn;

[0510] b. The grid-connected wind farm is regulated to operate in the maximum inductive reactive power output working mode;

[0511] c. Measure the time-series power at the grid-connected point of the grid-connected wind farm, record the active power and reactive power for at least 30 seconds, take the average power value every 0.2 seconds as one point, and calculate the average active power and reactive power within the second 15 seconds;

[0512] d. Adjust the active power of the grid-type wind farm in no-load operation mode to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn, and 0 respectively, and repeat steps b) to c);

[0513] e. Adjust the grid-type wind farm to operate in the maximum capacitive reactive power output working mode, and repeat steps c) to d);

[0514] f. With active power as the horizontal axis and reactive power as the vertical axis, draw the power envelope diagram of the grid-type wind farm.

[0515] g. Adjust the grid-type wind farm in full load operation mode with active power pn, repeat steps b) to f)

[0516] Step 4: Power factor regulation capability test;

[0517] The grid-type wind farm is required to be connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind farm output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind farm output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power. Tests are carried out respectively; verify the power factor adjustment capability of the grid-type wind farm in the grid control mode, with an accuracy of no more than 3%. The specific steps of the test method are as follows:

[0518] a. Set the grid-type wind farm to no-load operation mode, and adjust the active power to 0.25pn, 0.5pn, 0.75pn, and pn respectively;

[0519] b. Adjust the power factor of the grid-connected wind farm from leading 0.95 to lagging 0.95 continuously, with the adjustment range not exceeding 0.01, and measure and record the actual output power factor of the grid-connected wind farm;

[0520] c. Set the grid-type wind farm to full load operation mode, and adjust the active power to 0.25pn, 0.5pn, 0.75pn, and pn respectively;

[0521] d. Adjust the power factor of the grid-connected wind farm from leading 0.95 and continuously adjust it to lagging 0.95. The adjustment range shall not exceed 0.01. Measure and record the actual output power factor of the grid-connected wind farm and calculate the accuracy.

[0522] Power factor accuracy calculation formula: Among them, PFactual is the actual measured power factor, and PFset is the set power factor;

[0523] Step 5: Automatic voltage control test;

[0524] The grid-type wind farm is required to receive and respond to the AVC instructions sent by the dispatcher; the grid-type wind farm is connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind farm output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind farm output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power, and tests are carried out respectively; verify whether the grid-type wind farm has the automatic voltage control function; the automatic voltage control (AVC) test includes the following steps:

[0525] a. Check the AGC interface information and record it;

[0526] b. Issue rated power instructions to the grid-type wind farm and run continuously for 2 minutes;

[0527] c. Use the data acquisition device to collect the current, voltage and power of the test point and draw a real-time power curve;

[0528] d. Calculate the response time, regulation time and control accuracy of active power, requiring the active power control accuracy to be within ±2% pn, the active power response time to be no more than 30s, and the regulation time to be no more than 120s;

[0529] e. Issue rated power instructions to the grid-type wind farm and run continuously for 2 minutes;

[0530] f. Record the operating status of the grid-type wind farm after receiving the signal.

[0531] Step 6: Power quality test;

[0532] It is required that under no-load conditions, the grid-type wind farm output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind farm output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power, and tests are carried out respectively; verify the power quality of the grid-type wind farm under the grid control mode; the test content includes the following sub-steps:

[0533] a. RMS value of three-phase voltage during the test period;

[0534] b. RMS value of three-phase current during the test period;

[0535] c. The total distortion rate of the voltage waveform and the 95% probability statistical value during the test period. The total distortion rate shall not exceed 3%;

[0536] d. The total distortion rate of the current waveform during the test period and the 95% probability statistical value. The total distortion rate shall not exceed 3%;

[0537] e. The effective value of the fundamental wave and the 2-25th voltage harmonic components and 95% probability statistical values ​​during the test period;

[0538] f. The fundamental wave effective value and 2-25th current harmonic components and 95% probability statistical values ​​during the test period;

[0539] g. The three-phase voltage unbalance degree of the measuring point during the test period shall not exceed 2%;

[0540] h. The long-term flicker value of the voltage at the measuring point during the test period shall not exceed 0.8;

[0541] Step 7: Black start test;

[0542] The grid-type wind farm is required to have a black start function. During the black start period, there should be no obvious circulating current or oscillation problems between the converters, and the maximum deviation of the effective current value should not exceed 5%. The island grid self-starting capability of the grid-type wind farm converter is verified. The black start test includes the following sub-steps:

[0543] a. Turn off the switch of the whole station connection point, disconnect the load in the station, and close the transformer in the fan collector line in the station;

[0544] b. The backend or co-control sends a black start command, and the wind turbine converter starts automatically with no-load and zero-voltage of the upper transformer;

[0545] c. Record the relevant waveforms. After the voltage stabilizes, record the effective value of the line voltage, the frequency value, and the three-phase voltage imbalance. Example 4: Joint operation test of the grid-following and grid-building wind turbines

[0546] Step 1: Active Power Control Test

[0547] The grid-type wind turbine is required to be connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind turbine output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind turbine output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power. Tests are carried out separately to verify that the active power control accuracy of the grid-type wind turbine is within ±2%pn, the active power command response does not exceed 30s, and the adjustment time does not exceed 120s;

[0548] The test content includes the following sub-steps:

[0549] Power test;

[0550] aa. Set the active power of the grid-type wind turbine to 0;

[0551] b. Adjust the active power setting value step by step to 0, -0.25pn, -0.5pn, -0.75pn, -pn, -0.75pn, -0.5pn, -0.25pn, 0. Each power setting value runs continuously for 1 minute and records the measured data;

[0552] c. Calculate the response time, regulation time and control deviation of the active power control in the remote regulation mode of the grid-type wind turbine.

[0553] d. Change the power setting value to continuous operation time of 10 minutes and repeat steps b) to c)

[0554] 1.2) Power reduction test

[0555] a. Set the active power of the grid-type wind turbine to pn;

[0556] b. Adjust the active power setting value step by step to 0, 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0. Each power setting value runs continuously for 1 minute and records the measured data;

[0557] c. Calculate the response time, regulation time and control deviation of active power control;

[0558] d. Change the power setting value to continuous operation time of 10 minutes and repeat steps b) to c)

[0559] Step 2: Automatic generation control (AGC) test;

[0560] The grid-type wind turbine is required to receive and respond to the sent AGC instructions; the grid-type wind turbine is connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind turbine output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind turbine output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power. Tests are carried out separately; verify that the active power control accuracy of the grid-type wind turbine is within ±2%pn, the active power instruction response does not exceed 30s, and the adjustment time does not exceed 120s;

[0561] The test content includes the following sub-steps:

[0562] 2.1) Remote automatic power generation control test;

[0563] a. Set the wind turbines that operate in conjunction with the grid to remote regulation mode, and set the active power to 0;

[0564] b. The dispatcher manually issues AGC load instructions to adjust the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0;

[0565] c. Record the load of the unit;

[0566] 2.2) On-site automatic power generation control test;

[0567] d. Set the wind turbines that operate in conjunction with the grid to the local regulation mode, and set the active power to 0;

[0568] e. The wind turbines operating in conjunction with the grid manually issue AGC load instructions, and adjust the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0;

[0569] f. Record the load of the unit;

[0570] Step 3: Reactive Power Control Test

[0571] The grid-type wind turbine is required to be connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind turbine output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind turbine output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power. Tests are carried out separately to verify the reactive power regulation capability of the grid-type wind turbine in the grid control mode.

[0572] 3.1) Reactive power regulation capability test, the specific steps of the test method are as follows:

[0573] a. Set the wind turbine no-load operation mode for joint operation with the grid, and the active power is pn;

[0574] b. Adjust the wind turbines that operate in conjunction with the grid to operate in the maximum inductive reactive power output mode;

[0575] c. Measure the time-series power at the wind turbine grid connection point in joint operation with the grid / construction grid, record the active power and reactive power for at least 30 seconds, take the average power value every 0.2 seconds as one point, and calculate the average active power and reactive power within the second 15 seconds;

[0576] d. Respectively adjust the active power of the wind turbine in the no-load operation mode of the joint operation with the grid to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn, 0, and repeat steps b) to c);

[0577] e. Adjust the wind turbines that are operated in conjunction with the grid to operate in the maximum capacitive reactive power output mode, and repeat steps c) to d); f. Draw the power envelope diagram of the wind turbines that are operated in conjunction with the grid with active power as the horizontal axis and reactive power as the vertical axis. g. Adjust the wind turbines that are operated in conjunction with the grid to operate in the full load mode with active power pn, and repeat steps b) to f).

[0578] Step 4: Automatic Voltage Control (AVC) test;

[0579] The grid-type wind turbine is required to receive and respond to the AVC instructions sent by the dispatcher; the grid-type wind turbine is connected to the public power grid, and all parameters are adjusted to normal working conditions. Under no-load conditions, the wind turbine output active power is set to 0MW, and the actual measured value should be kept within ±0.5MW, that is, the control accuracy is less than ±1% of the rated power; under load conditions, the wind turbine output active power value is set, and the accuracy of the actual measured value is less than ±1% of the set power, and tests are carried out respectively; verify whether the grid-type wind turbine has the automatic voltage control function; the automatic voltage control (AVC) test includes the following steps:

[0580] 4.1) Automatic Voltage Control (AVC) test, the specific steps of the test method are as follows:

[0581] a. Check the AGC interface information and record it;

[0582] b. Issue a rated power command to the grid-type fan and run it continuously for 2 minutes;

[0583] c. Use the data acquisition device to collect the current, voltage and power of the test point and draw a real-time power curve;

[0584] d. Calculate the response time, regulation time and control accuracy of active power, requiring the active power control accuracy to be within ±2% pn, the active power response time to be no more than 30s, and the regulation time to be no more than 120s;

[0585] e. Issue a rated power command to the grid-type fan and run it continuously for 2 minutes;

[0586] f. Record the operating status of the grid-type fan after receiving the signal.

[0587] Step 5: One frequency modulation test;

[0588] The dead zone of primary frequency regulation can be determined according to the actual situation of the power system, and it is advisable to set it to ±(0.03~0.1) Hz. When the frequency deviation of the power system is greater than the dead zone range, and the active power of the fan is greater than 20%P, the fan should have the ability to participate in the primary frequency regulation of the power system, and the daily active power change of the fan ΔP;

[0589] 5.1) Primary frequency modulation dead zone test

[0590] a. Set the primary frequency modulation parameters of multiple grid-connected / structured energy storage power stations, connect multiple grid-connected / structured wind turbines and related testing and measuring equipment; b. Adjust multiple grid-connected / structured energy storage power stations to operate in no-load mode (operation instructions are issued by equipment manufacturers and monitored by recording and broadcasting software);

[0591] c. Gradually increase the grid connection point frequency value in steps of 0.01Hz until the active power starts to change regularly. Run each frequency setting value for 5s and record the output frequency value at the time when the active power changes regularly during the frequency disturbance process;

[0592] d. Gradually reduce the grid connection point frequency value in steps of 0.01 Hz until the active power starts to change regularly. Run each frequency setting value for 5 seconds and record the output frequency value at the time when the active power changes regularly during the frequency disturbance process;

[0593] e. Repeat c) to d);

[0594] f. Adjust multiple fans / grid fans to operate in pn constant power load mode;

[0595] g. Adjust multiple fans / grid fans to operate at no less than 20% pn;

[0596] h. Repeat c) to e).

[0597] 5.2) Frequency step disturbance test

[0598] a. The data acquisition device is connected to the voltage transformer (PT) and current transformer (CT) of the test point, and the frequency signal generator is connected to multiple grid / grid energy storage power station monitoring systems;

[0599] b. Adjust multiple follow-up / structure network fans to operate at pn constant power until multiple follow-up / structure network fans cut off conditions;

[0600] c. Multiple fans in the grid are tested under unlimited power and limited power operating conditions.

[0601] d. Use the frequency signal generator to output the frequency step disturbance signal, and test each working condition twice;

[0602] e. Record voltage, current, frequency and power values ​​during the test;

[0603] f. Calculate the primary frequency modulation response lag time, rise time, adjustment time and active power control deviation;

[0604] g. Adjust multiple follow-up / structure network fans to operate at pn constant power until multiple follow-up / structure network fans cut off conditions;

[0605] h. Test multiple wind turbines in the grid under unlimited power and limited power operation conditions;

[0606] i. Use the frequency signal generator to output the frequency step disturbance signal, and test each working condition twice;

[0607] j. Record voltage, current, frequency and power values ​​during the test;

[0608] k. Calculate the primary frequency modulation response lag time, rise time, regulation time and active power control deviation.

[0609] (The response lag time is the time required for the actual output active power change of the fan to reach 10% of the difference between the active power target value and the initial value, starting from the time when the system frequency increases or decreases more than one frequency modulation dead zone;

[0610] The rise time refers to the time required for the actual output active power of the fan to reach 90% of the difference between the active power target value and the initial value from the time the system frequency rises or falls by more than one frequency modulation dead zone. The adjustment time refers to the shortest time from the time the system frequency rises or falls by more than one frequency modulation dead zone, and the absolute value of the difference between the actual output active power of the fan and the active power target value does not exceed the allowable deviation.

[0611] 5.3) Primary FM limit test

[0612] a. Connect the data acquisition device to the voltage transformer (PT) and current transformer (CT) at the test point, and connect the frequency signal generator to multiple wind turbine monitoring systems;

[0613] b. Adjust multiple fans / network fans to operate at pn constant power until the fan operation cut-off condition;

[0614] c. Adjust multiple fans / grid fans to operate at 20% PN;

[0615] d. Set the frequency value of the grid connection point to gradually increase in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s. The maximum frequency difference step should not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process.

[0616] e. Set the frequency value of the grid connection point to be gradually reduced in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s. The maximum frequency difference step should not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process.

[0617] f. Adjust multiple fans / network fans to run at pn constant power until the fan cut-off condition;

[0618] g. Adjust multiple fans / grid fans to operate at 20% PN;

[0619] h. Repeat steps d) to g).

[0620] Step 6: Test the switching between the following and building network modes;

[0621] The network following and network building mode switching test content includes the following sub-steps:

[0622] 6.1) Test the switching from network building mode to network following mode;

[0623] a. Adjust the grid-type fan to operate in grid-type mode;

[0624] b. Adjust the grid-type fan to run at 50% PN for 3 minutes;

[0625] c. Switch the grid-type fan mode to the grid-following operation mode;

[0626] d. Record the voltage, current and power of the grid-connected wind turbine;

[0627] e. Conduct phase angle jump tolerance test; (the angle range can be selected between 15°-30°)

[0628] f. Record the status of the grid-forming wind turbine and confirm whether the grid-forming wind turbine has switched to the grid-following operation mode; (Based on the monitoring file of the recording and broadcasting software, the phase angle jump in the grid-forming control mode will cause fluctuations in active power, reactive power and current, while the phase angle jump in the grid-following control mode will not cause fluctuations in active power, reactive power and current)

[0629] g. Adjust the grid-type fan to run at 50% PN for 3 minutes;

[0630] h. Repeat steps c) to f).

[0631] 6.2) Test the switching mode from following network to building network.

[0632] a. Adjust the grid-type fan to operate in the grid-following mode;

[0633] b. Adjust the grid-type fan to run at 50% PN for 3 minutes;

[0634] c. Switch the grid-type fan mode to the grid-type operation mode;

[0635] d. Record the voltage, current and power of the grid-connected wind turbine;

[0636] e. Conduct phase angle jump tolerance test; (the angle range can be selected between 15°-30°)

[0637] f. Record the status of the grid-type wind turbine and confirm whether the grid-type wind turbine has switched to the grid-type operation mode; (According to the monitoring file of the recording and broadcasting software, the phase angle jump in the grid-type control mode will cause fluctuations in active power, reactive power and current, while the phase angle jump in the grid-following control mode will not cause fluctuations in active power, reactive power and current)

[0638] g. Adjust the grid-type fan to run at 50% PN for 3 minutes;

[0639] h. Repeat steps c) to f).

[0640] Embodiment 5: Conducting a joint operation test on the grid-following and grid-forming wind farms, with the same parameter settings as in Embodiment 4. This test method covers multiple aspects such as grid-forming wind turbine characteristic test, wind farm grid connection test, and joint operation test of grid-following and grid-forming wind turbines / wind farms. It can comprehensively evaluate the performance of grid-forming wind turbines in different scenarios and working conditions, and comprehensively verify the various technical characteristics of grid-forming wind turbines, including their key capabilities such as voltage control, frequency regulation, and dynamic response.

[0641] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. These changes involve related technologies well known to those skilled in the art, which fall within the scope of protection of the patent of the present invention. Many other changes and modifications can be made without departing from the concept and scope of the present invention. It should be understood that the present invention is not limited to specific embodiments, and the scope of the present invention is defined by the appended claims.

Claims

1. A multi-level full-scenario grid-connected wind turbine test method, characterized in that: It includes the grid characteristics test method of grid-forming wind turbines, the grid connection test method of grid-forming wind farms, the joint operation test method of grid-following and grid-forming wind turbines, and the joint operation test method of grid-following and grid-forming wind farms.

2. A multi-level full-scenario grid-connected wind turbine test method according to claim 1, characterized in that: The method for testing the network characteristics of a network-type wind turbine performs any one or more of the following steps: Step 1: low and high voltage cascading fault ride-through capability test, including low and high voltage cascading fault ride-through no-load test and low and high voltage cascading fault ride-through load test; Step 2: Low voltage ride through capability test, including low voltage ride through no-load test and low voltage ride through load test; Step 3: High voltage ride through capability test, including high voltage ride through no-load test and high voltage ride through load test; Step 4: frequency deviation adaptability test, including frequency adaptability no-load test and frequency adaptability load test; Step 5, a frequency modulation test, including a frequency modulation dead zone test, a frequency step disturbance test, and a frequency modulation limit test; Step 6, inertia response test, including inertia response no-load test and inertia response load test; Step 7, voltage deviation adaptability test, including voltage deviation adaptability no-load test and voltage deviation adaptability load test; Step 8: Power quality adaptability test, including harmonic voltage adaptability test, three-phase voltage unbalance adaptability test, and flicker adaptability test; Step 9, voltage phase mutation adaptability test, including voltage phase mutation adaptability no-load test and voltage phase mutation adaptability load test; Step 10, network following and network building mode switching test, including network building to network following mode switching test, network following to network building mode switching test; Step 11, reactive power regulation capability test, including reactive power response capability based on control, maximum inductive reactive power, maximum capacitive reactive power test, reactive power response capability based on control, reactive power set value control mode operation capability test, reactive power response capability based on control, reactive power step change test, voltage jump reactive power response no-load test, voltage jump reactive power response load test; Step 12, active power regulation capability test, including active power regulation capability maximum measured power test, active power regulation capability rise rate limit test, active power regulation capability set value control test; Step 13, damping control test; Step 14: Overload capacity test.

3. A multi-level full-scenario grid-connected wind turbine test method according to claim 2, characterized in that: The grid-type wind turbine network characteristic test method includes a grid-type wind turbine single-machine network characteristic test method and a grid-type wind turbine multi-machine coordinated control test method.

4. A multi-level full-scenario grid-connected wind turbine testing method according to claim 3, characterized in that: The single-machine network characteristic test method of the grid-type wind turbine is used to verify whether the grid-type wind turbine meets the low- and high-voltage cascading fault ride-through requirements, and executes any one or more of the steps 1-14: The low and high voltage cascading fault ride-through no-load test in step 1 adopts step 1-1: adjusting the voltage fault generating device to simulate the low and high voltage cascading faults of the line three-phase voltage and two-phase voltage, the voltage drop value is 0.15-0.25pu, and the duration is 605-645ms; The voltage rise value is 1.27~1.33pu, and the duration is 480~520ms, of which the voltage drop and voltage rise interval is 0~10ms. The voltage curve of the wind turbine grid connection point is recorded by a data acquisition device; The high voltage cascading fault ride-through load test in step 1 includes the following steps using steps 1-2: Step 1-2-1, put the fan disconnected during the no-load test into operation and connect it to the test equipment; Step 1-2-2, adjust the fan output power to 0.1~0.3pn; Step 1-2-3, control the voltage fault generating device to perform three-phase symmetrical voltage drop and rise, the voltage drop value is 0.15~0.25pu, the duration is 605~645ms, the voltage rise value is 1.27~1.33pu, the duration should be 480~520ms, and the voltage drop and voltage rise interval should be 0~10ms; Step 1-2-4, use a data acquisition device to record the waveforms of the voltage and current at the wind turbine grid connection point, and record the data from 10 seconds before the voltage drops to more than 15 seconds after the voltage returns to normal, and do it twice for each point; Step 1-2-5, adjust the fan output power to 0.9pn, and repeat steps (1-2-3) to (1-2-4); Step 1-2-6, control the voltage fault generating device to drop and raise the two-phase voltage. The voltage drop value should be 0.15-0.25 pu, the duration should be 605-645 ms, the voltage increase value should be 1.27-1.33 pu, the duration should be 480-520 ms, and the voltage drop and voltage increase interval should be 0-10 ms. Repeat steps (1-2-4) to (1-2-5); The low voltage ride-through no-load test in step 2 adopts step 2-1: adjusting the power grid simulation device to simulate the reduction of the three-phase voltage and the two-phase voltage of the line. When simulating the three-phase voltage reduction, the voltage amplitude is adjusted to 0.15-0.25pu for a test, the duration is 99980-100020ms, and the unit is disconnected from the power grid; when simulating the two-phase voltage reduction, the voltage amplitude is adjusted to 0.15-0.25pu for a test, the duration is 99980-100020ms, and the unit is disconnected from the power grid. The data acquisition device is used to record the voltage curve of the wind turbine grid connection point; The low voltage ride through load test in step 2 includes the following steps using step 2-2: Step 2-2-1, put the fan disconnected during the no-load test into operation and connect it to the test equipment; Step 2-2-2, fan output power 0.1~0.3pn; Step 2-2-3, control the power grid simulation device to perform three-phase symmetrical voltage reduction, first adjust the voltage amplitude to 0.85~0.95pu for two tests, the duration is 99980~100020ms, and then adjust the voltage amplitude range to 0.70~0.80pu, 0.45~0.55pu, 0.30~0.40pu, 0.15~0.25pu gradients and repeat the test in sequence; Step 2-2-4, use a data acquisition device to record the waveforms of the voltage and current at the wind turbine grid connection point, and record the data from 10 seconds before the voltage drops to more than 15 seconds after the voltage returns to normal, and do it twice for each point; Step 2-2-5, adjust the fan power to be greater than 0.9pn, and repeat steps (2-2-3) to (2-2-4); Step 2-2-6, control the power grid simulation device to reduce the two-phase voltage, first adjust the voltage amplitude to the range of 0.85-0.95pu for two tests, the duration should be 99980-100020ms, and then adjust the voltage amplitude range to 0.70-0.80pu, 0.45-0.55pu, 0.30-0.40pu, 0.15-0.25pu gradients, repeat the test in sequence, and repeat steps (2-2-4) to (2-2-5); In the step 3, the high voltage ride through no-load test adopts step 3-1: adjust the grid simulation device to simulate the increase of the three-phase voltage and the two-phase voltage of the line. When simulating the three voltage increases, adjust the voltage amplitude to 1.17-1.23pu for a test, the duration is 99980-100020ms, the unit is disconnected from the grid, and then set the voltage amplitude range to 1.22-1.28pu and 1.27-1.33pu respectively for another test, the duration is 9 9980~100020ms, when simulating two voltage reductions, adjust the voltage amplitude to 1.17~1.23pu for a test, the duration is 99980~100020ms, the unit operating condition should be disconnected from the grid, and then set the voltage amplitude range to 1.22~1.28pu and 1.27~1.33pu respectively for another test, the duration is 99980~100020ms, and use the data acquisition device to record the voltage curve of the wind turbine grid connection point; The high voltage ride through load test in step 3 includes the following steps using step 3-2: Step 3-2-1, put the fan disconnected during the no-load test into operation and connect it to the test equipment; Step 3-2-2, adjust the fan output power between 0.1 and 0.3 pn; Step 3-2-3, control the power grid simulation device to perform three-phase symmetrical voltage raising, first adjust the voltage amplitude to the range of 1.17-1.23pu for two tests, the duration is 99980-100020ms, and then repeat the test in the voltage amplitude range of 1.22-1.28pu and 1.27-1.33pu in sequence; Step 3-2-4, use a data acquisition device to record the waveforms of the voltage and current at the wind turbine grid connection point, and record the data from 10 seconds before the voltage rises to more than 15 seconds after the voltage returns to normal, and do it twice for each point; Step 3-2-5, adjust the fan output power to 0.9pn, and repeat steps (3-2-3) to (3-2-4); Step 3-2-6, control the power grid simulation device to raise the two-phase voltage, first adjust the voltage amplitude to 1.17~1.23pu for two tests, the duration should be 99980~100020ms, and then adjust the voltage amplitude range to 1.22~1.28pu and 1.27~1.33pu in gradients to repeat test steps (3-2-4)~(3-2-4) in sequence; The frequency deviation adaptability test in step 4 adopts step 4-1: adjusting the output frequency of the power grid adaptability detection device to 48-51.5Hz, the step length of the frequency adjustment is 0.1Hz, the duration of each step length is greater than 5s, and the actual frequency measured value and the corresponding adjustment parameter are recorded for each adjustment; adjusting the output frequency of the test device to gradually adjust from the rated frequency to 48Hz, 48.5Hz, 49Hz, 49.9Hz, 50.1Hz, 50.5Hz, 51Hz, 51.5Hz, the duration of each frequency setting value is greater than 5s, and the actual frequency measured value and the corresponding adjustment parameter are recorded for each adjustment; The frequency adaptability load test in step 4 adopts either step 4-2 or step 4-3: Step 4-2: The wind turbine operates normally and does not participate in system frequency regulation. During the test, the active power output of the wind turbine is greater than 10% of the rated power. The test adopts the following steps: (1) Keep the wind turbine in normal operation under rated voltage conditions, adjust the test device to gradually increase the frequency from the rated frequency in steps of 0.1 Hz, and each step should last for more than 20 seconds. When the frequency rises to 51.5 Hz, the test duration at this point shall not be less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid; (2) Keep the wind turbine in normal operation under rated voltage conditions, adjust the test device to gradually reduce the frequency from the rated frequency in steps of 0.1 Hz, and each step lasts for more than 20 seconds. When the frequency drops to 48 Hz, the test duration at this point is not less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid; Step 4-3: The wind turbine generator set operates under the condition of limited power and frequency modulation. During the test, the active power output of the wind turbine generator set is greater than 20% of the rated power. The test adopts the following steps: (1) Under rated voltage conditions, adjust the output frequency of the test device from the rated value to 48 Hz, 48.5 Hz, 49 Hz, 49.9 Hz, 50.1 Hz, 50.5 Hz, 51 Hz, and 51.5 Hz. The frequency retention time shall not be less than 30 s. After the frequency returns to the rated value, the test retention time shall not be less than 10 s. During the test, record whether the wind turbine is disconnected from the grid; (2) Under rated voltage conditions, set the output frequency of the test device one by one in the order of 48 Hz, 48.5 Hz, 49 Hz, 49.9 Hz, 50.1 Hz, 50.5 Hz, 51 Hz, and 51.5 Hz, and repeat step 4-2; The one-time frequency modulation dead zone test in step 5 includes the following steps using step 5-1: Step 5-1-1, set the primary frequency modulation parameters of the grid-type fan, and connect the grid-type fan and related testing and measuring equipment; Step 5-1-2, adjust the grid-type fan to operate in no-load mode; Step 5-1-3, gradually increase the grid connection point frequency value with a step size of 0.01Hz until the active power starts to change regularly. Each frequency setting value runs for 5s, and the output frequency value at the time when the active power changes regularly during the frequency disturbance process is recorded; Step 5-1-4, gradually reduce the grid connection point frequency value with a step size of 0.01Hz until the active power starts to change regularly. Run each frequency setting value for 5s, record the output frequency value steps at the time when the active power changes regularly during the frequency disturbance process, and repeat steps (5-1-3) to (5-1-4); Step 5-1-5, adjusting the grid-type fan to operate in pn constant power load mode; Step 5-1-6, adjust the grid-type fan to operate at no less than 20% pn, and repeat steps (5-1-3) to (5-1-4); The frequency step disturbance test in step 5, using step 5-2, includes the following steps: Step 5-2-1, connect the data acquisition device to the voltage transformer and current transformer at the test point, and connect the frequency signal generator to the grid-type wind turbine monitoring system; Step 5-2-2, adjust the grid-type fan to operate in no-load mode; Step 5-2-3, the grid-type wind turbine is respectively under the unlimited power and limited power operation states, and the active power is tested according to the grid-type wind turbine operation state and power range; Step 5-2-4, using a frequency signal generator to output a frequency step disturbance signal from 50 Hz to 50.15 Hz, 50 Hz to 50.205 Hz, 50 Hz to 49.85 Hz, and 50 Hz to 49.80 Hz, and each working condition is tested twice; Step 5-2-5, record the voltage, current, frequency and power values ​​during the test; Step 5-2-6, calculate the primary frequency modulation response lag time, rise time, adjustment time and active power control deviation; Step 5-2-7, adjust the grid-type fan to operate in pn constant power no-load mode; Step 5-2-8, using a frequency signal generator to output a frequency step disturbance signal from 50 Hz to 50.15 Hz, 50 Hz to 50.205 Hz, 50 Hz to 49.85 Hz, and 50 Hz to 49.80 Hz, and each operating condition is tested twice; Step 5-2-9, record the voltage, current, frequency and power values ​​during the test; Step 5-2-10, calculate the frequency modulation response lag time, rise time, adjustment time and active power control deviation, the active power control deviation calculation formula is: Where ΔP t is the change in active power of the wind farm, K f is the active frequency modulation coefficient, f is the power system frequency deviation, f N is the rated frequency of the power system, P t is the active power of the wind farm; The one-time frequency modulation amplitude limiting test in step 5, using step 5-3, includes the following steps: Step 5-3-1, connect the data acquisition device to the voltage transformer and current transformer of the test point, and connect the frequency signal generator to the grid-type wind turbine monitoring system; Step 5-3-2, adjust the grid-type fan to operate in no-load mode; Step 5-3-3, set the frequency value of the grid connection point to gradually increase in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s, and the frequency difference step does not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process; Step 5-3-4, set the frequency value of the grid connection point to gradually decrease in steps of 0.01Hz until the active power reaches the limit value and stops changing. Each frequency setting value runs for 5s, and the frequency difference step does not exceed ±0.5Hz. Record the output frequency value at the time when the active power changes regularly during the frequency disturbance process; Step 5-3-5, adjust the grid-type fan to operate in pn constant power no-load mode; Step 5-3-6, adjust the grid-type fan to operate at 20% pn, and repeat steps (5-3-3) to (5-3-6); The inertia response no-load test in step 6 adopts step 6-1: adjusting the output frequency of the grid adaptability detection device from 50 Hz, and changing it to 51.5 Hz at a change rate of 0.1 Hz / s, 0.5 Hz / s, and 1 Hz / s respectively, maintaining the frequency for no less than 10 seconds after stabilization, and restoring it to 50 Hz at the same change rate; repeating the above process, adjusting the frequency from 50 Hz to 48 Hz, and then restoring it to 50 Hz, and recording the actual frequency value and the corresponding adjustment parameter during each adjustment; The inertia response load test in step 6 includes the following steps using step 6-2: Step 6-2-1, keep the wind turbine in normal operation under rated voltage conditions, adjust the output frequency of the test device from 50Hz to 51.5Hz at a change rate of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, keep the test time for no less than 10s. After the frequency returns to the rated value at the same frequency change rate, keep the test time for no less than 10s. During the test, record whether the wind turbine is off the grid; Step 6-2-2, keep the wind turbine in normal operation under rated voltage conditions, adjust the output frequency of the test device from 50Hz to 48Hz at a change rate of 0.1Hz / s, 0.5Hz / s, and 1Hz / s respectively. After the frequency stabilizes, keep the test time for no less than 10s. After the frequency returns to the rated value at the same frequency change rate, keep the test time for no less than 10s. During the test, record whether the wind turbine is off the grid; The voltage deviation adaptability no-load test in step 7 adopts step 7-1: When the wind turbine is disconnected from the grid, adjust the output voltage of the grid adaptability detection device from 0.9pu to 1.1pu. The voltage adjustment steps are 1% and 2% of the rated voltage respectively. The duration of each step is not less than 5s. Record the measured voltage value and the corresponding adjustment parameters for each adjustment. The voltage deviation adaptability load test in step 7 includes the following steps using step 7-2: Step 7-2-1, keep the wind turbine in normal operation under rated frequency conditions, adjust the test device to gradually increase the voltage from the rated voltage in steps of 1% and 2% of the rated voltage, and each step lasts for no less than 20 seconds. When the voltage rises to 1.10pu, the test duration at this point is no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time the wind turbine is disconnected from the grid; Step 7-2-2, keep the wind turbine in normal operation under rated frequency conditions, adjust the test device to gradually reduce the voltage from the rated voltage in steps of 1% and 2% of the rated voltage, and each step should last for no less than 20 seconds. When the voltage drops to 0.90pu, the test duration at this point shall be no less than 30 minutes. During the test, if the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid; The harmonic voltage adaptability test in step 8 includes the following steps using step 8-1: Step 8-1-1, maintain normal operation of the unit under rated voltage and rated frequency conditions; Step 8-1-2, set the adjustment parameter to the set value of the 5Hz interharmonic voltage content rate during no-load test. If the wind turbine is not disconnected from the grid after the corresponding adjustment parameter lasts for 2 minutes, stop the test; if the wind turbine is disconnected from the grid, record the test duration and the wind turbine disconnection time; Step 8-1-3: the interharmonic voltage adaptability test method adopts step 8-1-2; Step 8-1-4, restore the voltage and frequency to the rated conditions and keep the unit running normally, set the adjustment parameters to the adjustment parameters corresponding to the set value of the third harmonic content rate during the no-load test, and stop the test if the wind turbine is not disconnected from the grid after 2 minutes. If the wind turbine is disconnected from the grid, record the test duration and the wind turbine disconnection time; Step 8-1-5: odd harmonic voltage adaptability test method adopts step 8-1-4; Step 8-1-6, restore the voltage and frequency to the rated conditions and keep the unit running normally, set the adjustment parameters to the adjustment parameters corresponding to the set value of the second harmonic content rate during the no-load test, and stop the test if the wind turbine is not disconnected from the grid after 2 minutes. If the wind turbine is disconnected from the grid, record the test duration and the time when the wind turbine is disconnected from the grid; Step 8-1-7, the even harmonic voltage adaptability test method adopts step 8-1-6; The three-phase voltage unbalance adaptability test in step 8 includes the following steps using step 8-2: Step 8-2-1, three-phase voltage unbalance adaptability no-load test, restore the output voltage and frequency of the grid adaptability detection device to maintain the rated value, set and adjust the three-phase voltage unbalance degree to 2% and 4% respectively, continue to run for 30min and 1min, and record the corresponding three-phase unbalance voltage value; Step 8-2-1, three-phase voltage unbalanced adaptive load test. The output voltage and frequency of the grid adaptability detection device are maintained at the rated value. The wind turbine is set to unity power factor control. During the test, the active power output of the wind turbine is greater than 50% of the rated power. The three-phase voltage unbalance is set to 2% and 4% respectively. The test lasts for 30 minutes and 1 minute, and the corresponding three-phase unbalanced voltage value is recorded. The flicker adaptability test in step 8 includes the following steps using step 8-3: Step 8-3-1, flicker adaptability no-load test, restore the grid adaptability detection device output voltage and frequency to maintain the rated value, set and adjust the three-phase voltage imbalance to 2% and 4% respectively, continue to run for 30min and 1min, and record the corresponding three-phase unbalanced voltage value; Step 8-3-2, flicker adaptive load test, the wind turbine is set to unity power factor control, during the test, the active power output of the wind turbine is greater than 30% of the rated power, the unit is kept in normal operation under the conditions of rated voltage and rated frequency, and the same adjustment parameters as the no-load test are set. If the wind turbine is not disconnected from the grid after 10 minutes, the test is stopped. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded; The voltage phase mutation adaptability no-load test in step 9 adopts step 9-1, when the wind turbine is disconnected from the grid, when the power supply voltage deviation at the test point is within the limit range of 0.9pu to 1.1pu, a test device is used to generate the required voltage phase mutation at the test point, and the voltage phase mutation angles are set to 5°, 30°, -5°, and -50° respectively, and the test is maintained for 30 seconds without disconnection from the grid. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded; The voltage phase mutation adaptive load test in step 9 adopts step 9-2. During the test, the active power output of the wind turbine is greater than 30% of the rated power. When the supply voltage deviation of the test point is within the limit range of 0.9pu to 1.1pu, the test device is used to generate the required voltage phase mutation at the test point. The voltage phase mutation angles are set to 5°, 30°, -5°, and -50° respectively. The wind turbine should be kept running without disconnecting from the grid for 30 seconds. If the wind turbine is disconnected from the grid, the test duration and the wind turbine disconnection time are recorded. The test of switching from network building mode to network following mode in step 10 adopts step 10-1 including the following steps: Step 10-1-1, adjusting the grid-type fan to operate in the grid-type mode; Step 10-1-2, adjust the grid-type fan to operate at 50% pn and run continuously for 3 minutes; Step 10-1-3, switch the grid-type wind turbine mode to the grid-following operation mode; Step 10-1-4, record the voltage, current and power of the grid-connected wind turbine; Step 10-1-5, perform phase angle jump tolerance test, with an angle range of 15° to 30°; Step 10-1-6, record the status of the grid-forming wind turbine and confirm whether the grid-forming wind turbine has switched to the grid-following operation mode; Step 10-1-7, adjust the grid-type fan to run at 50% pn, run continuously for 3 minutes, and repeat steps (10-1-3) to (10-1-6); The test of switching from the network-following mode to the network-building mode in step 10 adopts step 10-2 including the following steps: Step 10-2-1, adjusting the grid-type fan to operate in the grid-following mode; Step 10-2-2, adjust the grid-type fan to operate at 50% pn and run continuously for 3 minutes; Step 10-2-3, switch the grid-forming wind turbine mode to the grid-forming operation mode; Step 10-2-4, record the voltage, current and power of the grid-connected wind turbine; Step 10-2-5, perform phase angle jump tolerance test, with an angle range of 15° to 30°; Step 10-2-6, record the state of the grid-type fan and confirm whether the grid-type fan is switched to the grid-type operation mode; Step 10-2-7, adjust the grid-type fan to run at 50% pn, run continuously for 3 minutes, and repeat steps (10-2-3) to (10-2-6); The reactive power response capability maximum inductive reactive power and maximum capacitive reactive power test based on control in step 11 includes the following steps using step 11-1: Step 11-1-1, only collect data in the continuous operation state; Step 11-1-2, setting the active power of the wind turbine power station to pn, and adjusting the wind turbine power station to operate in a working mode of outputting the maximum inductive reactive power; Step 11-1-3, respectively adjust the charging active power of the wind power station to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn and 0, and measure the active power and reactive power at the output end of the grid-type wind turbine; Step 11-1-4, for each 10% rated power interval, collect at least 30 1-min active power and reactive power time series measurement data; Step 11-1-5, in each 1-min time period, the sampled data is converted into a 1-min average value using a block average method; Step 11-1-6, sorting the 1-min average value according to the interval method, and indicating in a table the average interval value of reactive power corresponding to the active power output of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the rated power; Step 11-1-7, adjust the wind turbine power station to operate in the maximum inductive reactive power output working mode, and repeat steps (11-1-3) to (11-1-6); The reactive power response capability based on the control in step 11 and the capability test of the reactive power set point control mode operation, using step 11-2, includes the following steps: Step 11-2-1, only collect data in the continuous operation state; Step 11-2-2, set the active power of the wind turbine power station to pn, adjust the charging active power of the wind turbine power station to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn and 0 respectively, and measure the active power and reactive power at the output end of the grid-type wind turbine; Step 11-2-3, for each 10% rated power interval, collect at least 30 1-min active power and reactive power time series measurement data; Step 11-2-4, in each 1-min time period, the sampled data is converted into a 1-min average value using a block average method; Step 11-2-5, sorting the 1-min average value according to the interval method, and presenting the reactive power setting value control capability test results in a chart form, and indicating in the table the reactive power average interval values ​​corresponding to the active power output of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the rated power; The reactive power step change test of reactive power response capability based on control in step 11 adopts step 11-3 to collect data under continuous operation, measure active power and reactive power at the output end of the grid-type wind turbine, the active power output is 50% of the rated power, the active power measurement result is the 1-min average value, the reactive power test result is the 0.2-s average value, and the reactive power adjustment should last for no less than 2 minutes under the capacitive reactive full-generation state and last for no less than 2 minutes under the inductive reactive full-generation state; In the step 11, the voltage jump reactive power response no-load test based on control is carried out by adopting step 11-4, adjusting the power grid simulation device, simulating the line three-phase voltage to rise to 1.1pu for a duration of not less than 625ms, adjusting the power grid simulation device, simulating the line three-phase voltage to drop to 0.9pu for a duration of not less than 625ms, and recording the grid-connected point voltage curve of the grid-type wind turbine; The voltage jump reactive power response load test in step 11 includes the following steps using step 11-5: Step 11-5-1, connect the grid-connected wind turbine disconnected during the no-load test to the grid for operation; Step 11-5-2, adjust the output power of the grid-type fan to 0.1-0.3pn; Step 11-5-3, control the power grid simulation device to perform symmetrical three-phase voltage disturbance, simulate the line three-phase voltage rise to 1.1pu for not less than 30 minutes, adjust the power grid simulation device, simulate the line three-phase voltage drop to 0.9pu for not less than 30 minutes; Step 11-5-4, record the waveforms of voltage and current at the grid-connected point of the grid-connected wind turbine, and record the data from 10 seconds before the voltage disturbance to more than 6 seconds after the voltage returns to normal, and do it twice for each point; Step 11-5-5, adjust the grid-type fan output power to 0.9pn, and repeat steps (11-5-3) to (11-5-4); The maximum measured power test of the active power regulation capability in step 12 adopts step 12-1 to collect data in the continuous operation state, measure the active power at the output end of the grid-type wind turbine, cut in the wind speed to 15m / s, and collect at least 5 10min time series of power measurement data for each 1m / s wind speed interval. The wind speed measurement result is the 10min average value. The power measurement data is converted into the 0.2s average value and the 1min average value within the measurement period by block averaging. When measuring the current, the full scale range should be twice the rated current of the grid-type wind turbine; In the step 12, the active power regulation capacity increase rate limit test is performed, using step 12-2, the grid-type wind turbine is started from the shutdown state, the power increase rate is set to 10% of the rated power / min, and the grid-type wind turbine is tested for 10 minutes after being connected to the grid. During the entire test process, the active power output obtained should be at least 50% of the rated power. The active power is measured at the output end of the grid-type wind turbine, and the test result in the report should be the average value of the active power every 0.2s; The active power regulation capability setting value control test in step 12 includes the following steps using step 12-3: Step 12-3-1: within the first 24 hours when the wind farm predicts that the average wind speed can meet the output power of the wind farm to reach more than 80% of the rated capacity of the wind farm, inquire about the power forecast results of surrounding wind farms. If the forecast results are close, report the estimated start time of the test to the dispatcher and prepare to start the test; Step 12-3-2: On-site personnel pay close attention to the ultra-short-term forecast of the wind power prediction system of the wind farm. If the predicted wind speed increases, they will formally apply to the dispatcher to start the test. During the test, the active power control mode of the wind farm under test is adjusted to the local control mode, and the wind farm will automatically issue the active power output command of the self-synchronous voltage source of the grid-forming wind turbine; Step 12-3-3, each test cycle is 10 minutes; Step 12-3-4, the rate limit function should be disabled during the test; Step 12-3-5, the active power setting value starts from 100% and decreases in steps of 20%, and the operation time of each setting value is 2 minutes; Step 12-3-6, during the entire test process, the available active power output is at least 0.9pn; Step 12-3-7, measuring the active power at the output end of the grid-type wind turbine; Step 12-3-8, the acquired active power output is read from the grid-type wind turbine control system. If it is not easy to read from the grid-type wind turbine control system, an approximate value can be obtained by referring to the power curve of the grid-type wind turbine based on the measured wind speed; The damping control test in step 13 comprises the following steps: Step 13-1, adjust the grid-type fan to operate at 50% pn; Step 13-2, adjust the damping coefficient of the grid-type fan to the minimum within the allowable range provided by the manufacturer; Step 13-3, perform power step at ±10% pn and continue running for 30 seconds; Step 13-4, recording the power and frequency curves of the grid-connected wind turbines; Step 13-5, adjusting the damping coefficient of the grid-type fan to the middle value and the maximum value of the damping coefficient range provided by the manufacturer; Step 13-6, compare the three test result curves to verify the effect and function of the damping control; Step 13-7, adjust the grid-type fan to operate at 50% pn, and repeat steps (13-2) to (13-6); The overload capacity test in step 14 may be performed by any one or more of the following steps: Step 14-1, 1.1 times overload test, adjust the grid-type wind turbine to the hot standby state, set the reactive power value corresponding to 1.1pn under the load state of the grid-type wind turbine, run it continuously for 10 minutes, measure the sequential power at the grid-type wind turbine connection point, take the average power value every 0.2s as one point, and record the measured data; Step 14-2, 1.2 times overload test, adjust the grid-type wind turbine to the hot standby state, set the grid-type wind turbine to carry out the reactive power value corresponding to 1.2pn under the load state, run continuously for 2 minutes, measure the sequential power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, and record the measured data; Step 14-3, 1.5 times overload test, adjust the grid-type wind turbine to the hot standby state, set the reactive power value corresponding to 1.5pn under the load state of the grid-type wind turbine, run continuously for 30s, measure the sequential power at the grid-type wind turbine connection point, take the average power value every 0.2s as one point, and record the measured data; Step 14-4, adjust the grid-type wind turbine to the hot standby state, set the grid-type wind turbine under load state, simulate the three-phase symmetrical fault of the line through the power grid simulation device to make the voltage drop to 0.2Un, and last for 10s, measure the timing power at the grid-type wind turbine grid connection point, take the average power value every 0.2s as one point, record the measured data, and verify whether the total current of the grid-type wind turbine can reach 3 times the rated current and last for 10s.

5. A multi-level full-scenario grid-connected wind turbine testing method according to claim 3 or 4, characterized in that: The grid-type wind turbine multi-machine coordinated control test method verifies whether multiple grid-type wind turbines meet the low and high voltage cascading fault ride-through requirements, and performs grid-type characteristic tests on multiple grid-type wind turbines.

6. A multi-level full-scenario grid-connected wind turbine testing method according to claim 1, characterized in that: The grid-connected wind farm test method comprises performing any one or more of the following steps: Step S1, active power control test, includes the following steps: Step S1-1, power increase test; Step S1-1-1, setting the active power of the grid-connected wind farm to 0; Step S1-1-2, adjust the active power setting value step by step to 0, -0.25pn, -0.5pn, -0.75pn, -pn, -0.75pn, -0.5pn, -0.25pn, 0, each power setting value runs continuously for 1 minute, and record the measured data; Step S1-1-3, calculating the response time, regulation time and control deviation of the active power control in the remote regulation mode of the grid-connected wind farm, the response time calculation formula is: T response =T start_adjust -T receive_command Among them, T start_adjust It is the moment when the wind farm starts to adjust its output power; T receive_command It is the moment when the wind farm receives the active power adjustment instruction; The adjustment time calculation formula is: T regulation =T stable_output -T start_adjust Among them, T stable_output It is the moment when the wind farm output power stabilizes near the new set value; T start_adjust It is the moment when the wind farm starts to adjust its output power; The control deviation calculation formula is: ΔP = P actual -P setpoint Among them, P actual is the active power actually output by the wind farm; P setpoint It is the active power required by the set value or dispatch instruction; Step S1-1-4, change the power setting value continuous operation time to 10 minutes, and repeat steps (S1-1-2) to (S1-1-3); Step S1-2, power reduction test, includes the following steps: Step S1-2-1, setting the active power of the grid-connected wind farm to pn; Step S1-2-2, adjust the active power setting value step by step to 0, 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0, each power setting value runs continuously for 1 minute, and record the measured data; Step S1-2-3, calculating the response time, regulation time and control deviation of active power control; Step S1-2-4, change the power setting value continuous operation time to 10 minutes, and repeat steps (S1-2-2) to (S1-2-3) Step S2: automatic power generation control test, including the following steps: Step S2-1, remote automatic power generation control test, set the grid-type wind farm to remote regulation mode, and set the active power to 0, manually issue AGC load instructions by the dispatcher, adjust the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0, and record the unit load situation; Step S2-2, local automatic power generation control test, set the grid-type wind farm to the local adjustment mode, and set the active power to 0, the grid-type wind farm manually issues the AGC load command, and adjusts the active power setting value step by step to 0.25pn, 0.5pn, 0.75pn, pn, 0.75pn, 0.5pn, 0.25pn, 0, and record the unit load situation; Step S3 reactive power regulation capability test includes the following steps: S3-1, set the grid-type wind farm to no-load operation mode, with active power of pn; S3-2, regulating the grid-connected wind farm to operate in the maximum inductive reactive power output working mode; S3-3, measure the time series power at the grid connection point of the grid-connected wind farm, record the active power and reactive power for at least 30 seconds, take the average power value every 0.2 seconds as one point, and calculate the average active power and reactive power within the second 15 seconds; S3-4, respectively adjusting the active power of the grid-type wind farm in the no-load operation mode to 0.9pn, 0.8pn, 0.7pn, 0.6pn, 0.5pn, 0.4pn, 0.3pn, 0.2pn, 0.1pn, 0, and repeating steps (S3-2) to (S3-3); S3-5, adjusting the grid-connected wind farm to operate in a maximum capacitive reactive power output working mode, and repeating steps (S3-3) to (S3-4); S3-6, with active power as the horizontal axis and reactive power as the vertical axis, draw the power envelope diagram of the grid-type wind farm; S3-7, adjusting the grid-connected wind farm to operate in full load mode with active power pn, and repeating steps (S3-2) to (S3-6); Step S4, power factor regulation capability test, includes the following steps: Step S4-1, setting the grid-type wind farm in no-load operation mode, and adjusting the active power to four points of 0.25pn, 0.5pn, 0.75pn, and pn respectively; Step S4-2, adjusting the power factor of the grid-type wind farm from leading 0.95 to lagging 0.95, with the adjustment amplitude not greater than 0.01, and measuring and recording the actual output power factor of the grid-type wind farm; Step S4-3, setting the grid-type wind farm to a full-load operation mode, and adjusting the active power to four points of 0.25pn, 0.5pn, 0.75pn, and pn respectively; Step S4-4, adjusting the power factor of the grid-type wind farm from leading 0.95 to lagging 0.95, with an adjustment range of no more than 0.01, measuring and recording the actual output power factor of the grid-type wind farm, and calculating the power factor accuracy, the power factor accuracy calculation formula is: Among them, PF 实际 is the actual measured power factor, PF 设定 is the set power factor; Step S5, automatic voltage control test, check AGC interface information, and record; send rated power command to the grid-type wind farm, and run continuously for 2 minutes; use the data acquisition device to collect the current, voltage and power of the test point, and draw a real-time power curve; calculate the response time, adjustment time and control accuracy of active power, requiring the active power control accuracy to be within ±2% pn, the active power response time not exceeding 30s, and the adjustment time not exceeding 120s; send rated power command to the grid-type wind farm, and run continuously for 2 minutes; record the operating status of the grid-type wind farm after receiving the signal; Step S6, power quality test, three-phase voltage RMS value during the test period; three-phase current RMS value during the test period; total voltage waveform distortion rate and 95% probability statistical value during the test period, the total distortion rate does not exceed 3%; total current waveform distortion rate and 95% probability statistical value during the test period, the total distortion rate does not exceed 3%; fundamental wave effective value and 2-25th voltage harmonic components and 95% probability statistical value during the test period; fundamental wave effective value and 2-25th current harmonic components and 95% probability statistical value during the test period; three-phase voltage unbalance at the measuring point during the test period, the unbalance does not exceed 2%; long-term flicker value of the voltage at the measuring point during the test period, the flicker value does not exceed 0.8; Step S7, black start test; disconnect the switch of the entire station grid connection point, disconnect the load in the station, and close the transformer in the wind turbine collection line in the station; the background or cooperative control sends a black start command, and the wind turbine converter starts automatically with no load and zero voltage with the upper transformer; record the relevant waveforms, wait for the voltage to stabilize, and then record the line voltage effective value, frequency value and three-phase voltage imbalance.

7. A multi-level full-scenario grid-connected wind turbine test method according to claim 1, characterized in that: The grid-following and grid-building wind turbine joint operation test method and the grid-following and grid-building wind farm joint operation test method both execute any one or more of the following steps: active power control test; automatic power generation control test; reactive power control test; automatic voltage control test; primary frequency modulation test; grid-following and grid-building mode switching test.

8. A multi-level full-scenario grid-connected wind turbine testing method according to claim 7, characterized in that: The following network and networking mode switching test includes a networking to following network mode switching test and a following network to networking mode switching test.

9. A multi-level full-scenario grid-connected wind turbine test method according to claim 8, characterized in that: The test of switching from network building mode to network following mode includes the following steps: Step a, adjusting the grid-forming wind turbine or wind farm to operate in the grid-forming mode; Step b, adjusting the grid-type wind turbine or wind farm to operate at 50% pn for 3 minutes; Step c, switching the grid-connected wind turbine or wind farm mode to a grid-following operation mode; Step d, recording the voltage, current and power of the grid-connected wind turbine or wind farm; Step e, performing a phase angle jump tolerance test, with an angle of 15° to 30°; Step f, recording the state of the grid-connected wind turbine or wind farm, and confirming whether the grid-connected wind turbine or wind farm has switched to a grid-following operation mode; Step g, adjusting the grid-type wind turbine or wind farm to operate at 50% pn for 3 minutes continuously; Step h, repeat steps (c) to (f).

10. A multi-level full-scenario grid-connected wind turbine testing method according to claim 8, characterized in that: The test of switching from network following to network building mode includes the following steps: Step a1, adjusting the grid-connected wind farm to operate in a grid-following mode; Step b1, adjusting the grid-type wind farm to operate at 50% pn for 3 minutes; Step c1, switching the grid-building wind farm mode to the grid-building operation mode; Step d1, recording the voltage, current and power of the grid-connected point of the grid-connected wind farm; Step e1, performing a phase angle jump tolerance test at an angle of 15° to 30°; Step f1, recording the state of the grid-forming wind farm, and confirming whether the grid-forming wind farm is switched to the grid-forming operation mode; Step g1, adjusting the grid-type wind farm to operate at 50% pn for 3 minutes; Step h1, repeat steps (c1) to (f1).

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