Yaw error testing method for wind turbines based on feedforward technology

Abstract

The present invention belongs to the field of wind turbine yaw error testing methods based on feedforward technology, and in particular, a wind turbine yaw error testing method based on feedforward technology. In view of the problem that existing aircraft do not have heading correction technology and yaw causes power generation loss of wind turbines, the following solution is proposed, which includes the following steps: S1: installing a laser wind measurement radar on the top of the nacelle to measure the wind speed and wind direction in front of the wind rotor; S2: performing yaw error correction, including static correction and dynamic correction; static correction: achieved by modifying the offset parameter, that is, adding a fixed direction offset to the detection value of all wind direction errors at all wind speeds; S3: technical effect acceptance. The present invention analyzes the yaw error angle of the wind turbine and adjusts the corresponding parameters in the main control system, so that the wind turbine can better yaw into the wind, absorb wind energy to the greatest extent, and ultimately reduce the load of the unit.

Description

Technical Field

[0001] The present invention relates to the field of wind turbine yaw error testing methods, and in particular to a wind turbine yaw error testing method based on a feedforward technology. Background Art

[0002] Yaw error is common in wind turbines. Many wind turbine manufacturers and wind farm owners have long observed that the nacelle's orientation varies during operation. Research shows that the average yaw error of wind turbines in most wind farms is around 10-12 degrees, but only some with significant yaw can be visually identified; the majority cannot be determined visually. Due to the lack of suitable measurement methods for yaw error and the lack of quantification of the energy loss caused by yaw error, yaw error has not been taken seriously. Statistics from another wind turbine test also show that over 75% of wind turbines require yaw correction, and over 50% of turbines have yaw error that significantly impacts energy production. Yaw error is common in wind turbines, but wind measurement equipment has traditionally been mounted at the tail of the turbine. This is affected by rotor turbulence and the nacelle's shape, making it difficult to accurately measure wind speed and direction. Yaw error is a systemic problem that cannot be addressed by existing technologies. Therefore, it is necessary to utilize lidar systems to evaluate turbine performance and improve power generation.

[0003] The most direct consequence of yaw error is a loss in wind turbine power generation, and the power curve most directly reflects the difference in power generation before and after the correction. At an average yaw error of 12 degrees, yaw error correction increases turbine power generation and optimizes the power curve, increasing power generation by approximately 1%-4% annually. The reduced load also increases the service life of major components. Because the improvement is reflected in increased power below rated wind speeds, the effect is most pronounced in areas with lower average annual wind speeds.

[0004] Causes of yaw error

[0005] Traditional wind turbine wind measurement devices are installed at the tail of the wind turbine. Due to the influence of the wind rotor disturbance and the shape of the nacelle, it is impossible to accurately measure wind speed and direction. Yaw error is a systemic problem that cannot be solved by existing traditional technologies. The yaw error of wind turbines mainly comes from three aspects:

[0006] 1. Installation error of wind measuring equipment: Since most wind turbine anemometers are not installed with calibration equipment, an installation error of ±2 to 10 degrees may usually occur.

[0007] 2. Influence of wind rotor vortex: After the wind passes through the rotating wind rotor, it will generate many vortices, which makes the wind vane installed at the rear of the cabin unable to accurately measure the instantaneous wind direction at that time. When dealing with these vortices, most wind turbine manufacturers average the wind direction for 25 seconds to 2 minutes to filter out the influence of the vortex on the wind direction measurement. However, since the average value is used as the current instantaneous value to control the yaw action of the wind turbine, it will cause certain errors and discreteness of the wind turbine yaw.

[0008] 3. Errors caused by swirling airflow on the nacelle surface: When air flows through a rotating machine, it generates a swirling airflow field behind it. This airflow field, as it moves across the surface of the wind turbine nacelle, deflects the wind vane behind the nacelle, causing wind direction measurement errors. This error is related to the terrain and orientation of the wind turbine, so the error varies for each wind turbine in the same wind farm.

[0009] Yaw error power loss

[0010] The most direct consequence of yaw error is a loss in wind turbine power generation. Recent research by renowned independent research institutions at home and abroad, such as Risoe, GL-GH, NERL, and ECN, indicates that yaw error and power generation loss follow a cos² relationship: ΔP = 1-cos²θ, where θ is the wind turbine's yaw error angle (as shown in the "Yaw Angle" figure below). It is generally believed that the average yaw error of a wind turbine is within 4 degrees. Since the impact on power generation is minimal, static adjustment is not required in actual calibration. However, adjustments are required for wind turbines with yaw errors exceeding 4 degrees.

[0011] However, it is not just the average yaw error of the wind turbine that causes power generation loss to the wind turbine. In essence, the loss of wind turbine power generation is the yaw error of the wind turbine at each moment, that is, the discreteness of the wind turbine yaw is an important factor in power generation loss.

[0012] Existing aircraft do not have the technology to correct their heading, and the most direct consequence of heading is the loss of wind turbine power generation. Summary of the Invention

[0013] The purpose of the present invention is to solve the shortcomings of existing aircraft that have no heading correction technology and yaw causes power loss of wind turbines, and to propose a wind turbine yaw error testing method based on feedforward technology.

[0014] In order to achieve the above object, the present invention adopts the following technical solutions:

[0015] The wind turbine yaw error test method based on feedforward technology includes the following steps:

[0016] S1: Install a laser wind radar on the top of the nacelle to measure the wind speed and direction in front of the wind rotor;

[0017] S2: Perform yaw error correction, including static correction and dynamic correction;

[0018] Static correction: This is achieved by modifying the offset parameter, that is, at all wind speeds, an offset in a fixed direction is added to the detection value of all wind direction errors, and then output to the yaw control.

[0019] Dynamic correction: Based on the yaw error measured by the LiDAR, it is output to the yaw control algorithm, which can effectively reduce the discrete type of yaw error. It can be executed through the Windtimizer module, or directly connect the Limao product to the wind turbine main control system.

[0020] S3: Technical effect acceptance;

[0021] S4: Information input.

[0022] Preferably, in S1, by analyzing the yaw error angle of the wind turbine and adjusting the corresponding parameters in the main control system, the wind turbine can be better yawed to face the wind and absorb wind energy to the greatest extent, thereby ultimately reducing the load on the unit, increasing the service life of large components, and increasing the power generation of the unit by 1-4% per year.

[0023] Preferably, in S1, the specific installation of the laser wind measurement radar includes the following steps:

[0024] First, fix the tripod to the pre-selected installation position on the cabin roof. Open a hole (diameter Φ10mm) on the cabin roof for the wire rope to pull and fix the laser head and tripod. Complete the waterproof sealing work.

[0025] Second, a hole (diameter Φ48mm) is opened on the top of the cabin to allow the armored cable to pass through and connect to the control unit inside the cabin, while also completing the waterproof sealing work.

[0026] Third, the spindle centerline is confirmed inside the nacelle and projected onto the nacelle top using a laser alignment tool.

[0027] Fourth, align the laser measuring head outside the cabin along the center line and lock the measuring head.

[0028] Fifth, installation in the cabin, including: completing all wiring; the power module 220VAC and the control unit are installed by using strong magnets to absorb the cabinet; the RS485 serial communication cable is connected to the communication module of the main control cabinet; the RJ45 Ethernet cable is connected to the main control switch (if the switch can be connected to Ethernet).

[0029] Sixth, power on the equipment and complete debugging.

[0030] In S2, the optimization strategies for several cases of yaw error correction are as follows:

[0031] Working condition 1: The yaw discreteness is small and the average value is small, which is the ideal result of yaw correction (control).

[0032] Working condition 2: The yaw discreteness is large and the average value is small. Dynamic yaw correction or the Windtimizer module is required for yaw correction. Static yaw correction strategy cannot be used.

[0033] Working condition 3: The yaw dispersion is large and the average value is large. Dynamic yaw correction or the Windtimizer module is required for yaw correction. The static yaw correction strategy is not ideal.

[0034] Working condition 4: The yaw discreteness is small and the average value is large, so only the static yaw correction strategy is required.

[0035] Preferably, in S2, the steps of implementing yaw error correction include:

[0036] First, the laser wind measuring equipment is installed on the top of the wind turbine, parallel to the main shaft of the wind turbine, and shoots two laser beams forward at an angle of 30 degrees to the left and right in front of the wind turbine. By using the Doppler effect of the laser reflected back on the aerosols in the air, the relative wind direction between the wind 70 meters ahead and the main shaft direction of the wind turbine can be calculated.

[0037] Second, the lidar's internal software processes the measured data, automatically filtering out data where the laser beam is obstructed by turbine blades. Because the wind is measured 70 meters in front of the turbine, the airflow is largely unaffected by the turbine's rotor, allowing the lidar to accurately measure wind conditions directly at the rotor's surface.

[0038] Preferably, in said S3, after the correction is completed, the absolute value of the average yaw error of the wind turbine in the wind speed range of 3 to 14 m / s is less than 2 degrees.

[0039] Method 1: According to The power loss provided by Wind Turbine Power Performance Verification in Complex Terrain and Wind Farms follows the COS2 relationship to calculate the improvement in annual power generation: △P = (cos2)2 - (cos1)2, where 1 and 2 are the static and dynamic yaw error angles of the wind turbine, respectively.

[0040] Method 2: Filter out data from abnormal wind turbine operating conditions based on power curve measurements (this method applies to wind turbines that meet conditions 1 and 2 mentioned in Section 1). Calculate the wind turbine's NTF using a 10-minute average. Use the NTF to correct the second-level or 10-minute wind speed measured by the nacelle anemometer. Use the corrected wind speed to calculate the power curve using the Bin method of IEC61400-12, with a wind speed interval of 0.5 m / s. Calculate the AEP based on the Weibull distribution parameters of the wind resource in the feasibility study report. Calculate the optimization effect (AEP2 - AEP1) / AEP1 * 100%.

[0041] Preferably, in said S4, the project transformation has no impact on the hardware of the entire engineering project or equipment, but information needs to be provided for analysis and evaluation.

[0042] In the present invention, the beneficial effects of the wind turbine yaw error testing method based on the feedforward technology are as follows:

[0043] The present invention analyzes the yaw error angle of the wind turbine and adjusts the corresponding parameters in the main control system, so that the wind turbine can yaw better to face the wind and absorb wind energy to the greatest extent, ultimately reducing the load on the unit and increasing the service life of large components. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of the wind turbine yaw error testing method based on the feedforward technology proposed in the present invention;

[0045] Figure 2 This is a schematic diagram of the algorithm for static yaw correction proposed in the present invention;

[0046] Figure 3 This is the yaw correction optimization strategy diagram proposed by the present invention;

[0047] Figure 4 This is a schematic diagram of the installation and measurement of the laser wind measurement equipment proposed in the present invention;

[0048] Figure 5 This is a schematic diagram of the external installation of the cabin proposed by the present invention;

[0049] Figure 6 This is a schematic diagram of the installation in the cabin proposed by the present invention. DETAILED DESCRIPTION

[0050] The technical solution of this embodiment will be clearly and completely described below in conjunction with the drawings in this embodiment. Obviously, the described embodiment is only a part of this embodiment, rather than all the embodiments.

[0051] Reference Figure 1-6 The wind turbine yaw error test method based on feedforward technology includes the following steps:

[0052] S1: Install a laser wind radar on the top of the nacelle to measure the wind speed and direction in front of the wind rotor;

[0053] S2: Perform yaw error correction, including static correction and dynamic correction;

[0054] Static correction: This is achieved by modifying the offset parameter, that is, at all wind speeds, an offset in a fixed direction is added to the detection value of all wind direction errors, and then output to the yaw control.

[0055] Dynamic correction: Based on the yaw error measured by the LiDAR, it is output to the yaw control algorithm, which can effectively reduce the discrete type of yaw error. This can be performed through the Windtimizer module, or by directly connecting the LiMao product to the wind turbine main control system;

[0056] S3: Technical effect acceptance;

[0057] S4: Information input.

[0058] Reference Figure 5-6 In this embodiment, in S1, by analyzing the yaw error angle of the wind turbine and adjusting the corresponding parameters in the main control system, the wind turbine can be better yawed to face the wind and absorb wind energy to the greatest extent, ultimately reducing the load on the unit, increasing the service life of major components, and increasing the power generation of the unit by 1-4% per year;

[0059] The specific installation of the laser wind radar includes the following steps:

[0060] First, secure the tripod to the pre-selected mounting location on the cabin roof. Open a hole (Ø10mm) on the cabin roof for the wire rope to secure the laser head and tripod. Complete the waterproof seal. (Estimated time: 1 hour)

[0061] Second, a hole (diameter Φ48mm) is opened on the top of the cabin to allow the armored cable to pass through and connect to the control unit inside the cabin. At the same time, waterproof sealing is completed (estimated to take 1 hour).

[0062] Third, confirm the spindle centerline inside the nacelle and use a laser alignment tool to project the centerline onto the top of the nacelle (estimated time: 30 minutes).

[0063] Fourth, align the laser measuring head on the outside of the cabin along the centerline and lock the measuring head (estimated to take 1 hour).

[0064] Fifth, installation in the cabin, including: completing all wiring; attaching the 220VAC power module and control unit to the cabinet using strong magnets; connecting the RS485 serial communication cable to the communication module in the main control cabinet; and connecting the RJ45 Ethernet cable to the main control switch (if the switch can be connected to Ethernet). (Estimated time: 1 hour)

[0065] Sixth, power on the equipment and complete debugging.

[0066] Reference Figure 1 In this embodiment, in S2, the optimization strategies for several cases of yaw error correction are as follows:

[0067] Working condition 1: The yaw discreteness is small and the average value is small, which is the ideal result of yaw correction (control).

[0068] Working condition 2: The yaw discreteness is large and the average value is small. Dynamic yaw correction or the Windtimizer module is required for yaw correction. Static yaw correction strategy cannot be used.

[0069] Working condition 3: The yaw dispersion is large and the average value is large. Dynamic yaw correction or the Windtimizer module is required for yaw correction. The static yaw correction strategy is not ideal.

[0070] Working condition 4: The yaw discreteness is small and the average value is large, so only the static yaw correction strategy is required.

[0071] Domestic measurement results show that yaw dispersion is much more severe than that of foreign brand wind turbines. This means that the wind turbines are exposed to less than optimal wind conditions more often, resulting in greater deviations. Therefore, correcting yaw error can significantly improve power generation. Correcting yaw error increases power generation, optimizes the power curve, and improves turbine load. Since yaw error correction improves power generation by increasing power below rated wind speeds, the effect is more pronounced in areas with lower average annual wind speeds.

[0072] Reference Figure 2-4 In this embodiment, the steps of implementing yaw error correction include:

[0073] First, the laser wind measuring equipment is installed on the top of the wind turbine, parallel to the main shaft of the wind turbine, and shoots two laser beams forward at an angle of 30 degrees to the left and right in front of the wind turbine. By using the Doppler effect of the laser reflected back on the aerosols in the air, the relative wind direction between the wind 70 meters ahead and the main shaft direction of the wind turbine can be calculated.

[0074] Second, the LiDAR's internal software processes the measured data, automatically filtering out data where the laser beam is blocked by turbine blades. Because the wind is measured 70 meters in front of the turbine, the airflow is largely unaffected by the turbine's rotors, allowing the LiDAR to accurately measure wind conditions directly at the rotor surface.

[0075] The specific installation location and bracket should be determined based on the cabin roof shape and layout. The external power supply can be 230VAC 2A, 115VAC 4A, or 24VDC with a maximum of no more than 10A, and normal operation is 4-5A.

[0076] Reference Figure 3 In this embodiment, in S3, after the correction is completed, the absolute value of the average yaw error of the wind turbine in the wind speed range of 3 to 14 m / s is less than 2 degrees.

[0077] Method 1: According to The power loss provided by Wind Turbine Power Performance Verification in Complex Terrain and Wind Farms follows the COS2 relationship to calculate the improvement in annual power generation: ΔP = (cos2)2 - (cos1)2, where 1 and 2 are the static and dynamic yaw error angles of the wind turbine, respectively.

[0078] Method 2: Filter out data from abnormal wind turbine operating conditions based on power curve measurements (this method applies to wind turbines that meet conditions 1 and 2 mentioned in Section 1). Calculate the wind turbine's NTF using a 10-minute average. Use the NTF to correct the second-level or 10-minute wind speed measured by the nacelle anemometer. Use the corrected wind speed to calculate the power curve using the Bin method of IEC61400-12, with a wind speed interval of 0.5 m / s. Calculate the AEP based on the Weibull distribution parameters of the wind resource in the feasibility study report. Calculate the optimization effect (AEP2 - AEP1) / AEP1 * 100%.

[0079] Previous domestic test results show that the yaw error of most wind turbines is between 6 and 8 degrees. Using the cos² relationship, this yields a 1-2% increase in annual energy production. Using the Windtimizer module, the annual energy production increase will be greater than the cos² relationship. The specific amount of improvement depends on the turbine's yaw control strategy and the frequency of wind direction changes.

[0080] In this embodiment, in S4, the project transformation has no impact on the hardware of the entire project or equipment, but the following information is required for analysis and evaluation:

[0081]

[0082] The following data analysis and evaluation should be provided for the software:

[0083]

[0084] Yaw error can cause two problems for turbine operation: a reduction in annual power generation and increased load and vibration. Reducing yaw error to a controllable range not only resolves these two issues but also brings direct economic benefits.

[0085] The above is only a preferred specific implementation method of this embodiment, but the protection scope of this embodiment is not limited to this. Any technician familiar with this technical field can make equivalent replacements or changes based on the technical solution and inventive concept of this embodiment within the technical scope disclosed in this embodiment, and they should be covered by the protection scope of this embodiment.

Claims

1. A wind turbine yaw error test method based on feedforward technology, characterized in that: The following steps are involved: S1: Install a laser wind radar on the top of the nacelle to measure the wind speed and direction in front of the wind rotor; S2: Perform yaw error correction, including static correction and dynamic correction; Static correction: This is achieved by modifying the offset parameter. That is, at all wind speeds, an offset in a fixed direction is added to the detected values ​​of all wind direction errors, and then output to the yaw control. Dynamic correction: Based on the yaw error measured by the lidar, it is output to the yaw control algorithm, which can effectively reduce the discrete type of yaw error. It can be executed through the Windtimizer module, or directly connect the Limao product to the wind turbine main control system. S3: Technical effect acceptance; S4: information input; In S2, the optimization strategies for several cases of yaw error correction are as follows: Working condition 1: The yaw dispersion is small and the average value is small, which is the ideal result of yaw correction; Condition 2: The yaw dispersion is large and the average value is small. Dynamic yaw correction or the Windtimizer module is required for yaw correction. Static yaw correction strategy cannot be used. Condition 3: The yaw dispersion is large and the average value is large. Dynamic yaw correction or the Windtimizer module is required for yaw correction. The static yaw correction strategy is not ideal. Working condition 4: The yaw discreteness is small and the average value is large, so only the static yaw correction strategy is required.

2. The wind turbine yaw error testing method based on feedforward technology according to claim 1, characterized in that: In S1, the yaw error angle of the wind turbine is analyzed and the corresponding parameters are adjusted in the main control system, so that the wind turbine can yaw better to face the wind and absorb wind energy to the greatest extent. This ultimately reduces the load on the unit, increases the service life of major components, and increases the power generation of the unit by 1-4% per year.

3. The wind turbine yaw error testing method based on feedforward technology according to claim 1, characterized in that: In S1, the specific installation of the laser wind measurement radar includes the following steps: First, fix the tripod bracket to the pre-selected installation position on the top of the cabin. Open a hole on the top of the cabin for the steel wire rope to pull and fix the laser head and tripod to complete the waterproof sealing work; Second, a hole is opened on the top of the cabin for the armored cable to pass through to connect to the control unit inside the cabin, while also completing the waterproof sealing work; Third, confirm the spindle centerline inside the nacelle and use a laser alignment tool to project the centerline onto the top of the nacelle; Fourth, align the laser measuring head outside the cabin according to the center line and lock the measuring head; Fifth, installation in the cabin, including: completing all wiring; installing the 220VAC power module and control unit using strong magnets to attach to the cabinet; connecting the RS485 serial communication cable to the communication module in the main control cabinet; and connecting the RJ45 Ethernet cable to the main control switch. Sixth, power on the equipment and complete debugging.

4. The wind turbine yaw error testing method based on feedforward technology according to claim 1, characterized in that: In S2, the steps of implementing the yaw error correction include: First, the laser wind measuring device is installed on the top of the wind turbine, parallel to the wind turbine main shaft. It shoots two laser beams forward at an angle of 30 degrees to the left and right of the wind turbine. The Doppler effect of the laser reflected by the aerosol in the air is used to calculate the relative wind direction between the wind at 70 meters ahead and the wind turbine main shaft direction. Second, the internal software of the lidar can process the measured data and automatically filter out the data when the laser beam is blocked by the wind turbine blades. Since the wind measured is 70 meters in front of the wind turbine, the airflow is basically not disturbed by the wind turbine rotor, and the lidar accurately measures the wind conditions blowing onto the wind turbine rotor surface.

5. The wind turbine yaw error testing method based on feedforward technology according to claim 1, characterized in that: In S3, after the correction is completed, the absolute value of the average yaw error of the wind turbine in the wind speed range of 3 to 14 m / s is less than 2 degrees.

6. The wind turbine yaw error testing method based on feedforward technology according to claim 1, characterized in that: In S4, the technical transformation has no impact on the hardware of the entire project or equipment, and information needs to be provided for analysis and evaluation.

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