A method and monitoring device for reducing rain erosion of a blade

Abstract

The application discloses a method for reducing blade rain erosion, comprising the following steps: step 1, a sensor monitors the impact force of raindrops on the surface of the blade in real time; step 2, a database of impact force-damage is established, and a unit control damage value is formulated according to the number of rainfall days in the local wind field design life; step 3, the wind wheel rotating speed is controlled in combination with the unit control damage value and the current damage value; and step 4, a data collector counts the cumulative damage of the current blade, and when the cumulative damage reaches the total damage, a fault warning of blade rain erosion is performed. A monitoring device for reducing blade rain erosion comprises a piezoelectric impact sensor arranged at the leading edge of a blade, the piezoelectric impact sensor is connected with a main control system through a data collector, and the main control system is connected with a converter and a monitoring system. The wind wheel rotating speed can be accurately controlled to reduce the damage of rain erosion, meanwhile, the power generation can be maximized without losing too much, thereby providing technical support for subsequent protection of the leading edge of a large wind power blade.

Description

Technical Field

[0001] This invention relates to the field of wind turbine technology, and in particular to a method and monitoring device for reducing blade rain erosion. Background Technology

[0002] Rain erosion is currently the most significant factor contributing to corrosion at the leading edge of wind turbine blades, especially in offshore wind farms where high humidity and rainfall exacerbate its effects. Rain erosion refers to the corrosion caused by raindrops impacting the high-speed leading edge of the blade. The blade tip has the highest linear velocity across the entire blade, and the leading edge is the primary point of contact with air and rainwater during wind turbine blade rotation; therefore, the corrosion at the blade tip is the most severe.

[0003] Current wind turbine blades have tip linear velocities reaching 100 m / s or even higher. At these high speeds, raindrops impacting the blade surface generate tremendous force, damaging the protective coating. After the damaged coating is washed away by rainwater, the unaffected areas are exposed and subjected to further damage. Leading-edge corrosion negatively impacts aerodynamic performance; even minor corrosion can reduce annual power generation by 5%, while severe corrosion can lead to even greater losses. Therefore, effectively reducing rain erosion on wind turbine blades is a pressing issue that needs to be addressed. Summary of the Invention

[0004] The purpose of this invention is to provide a method and monitoring device for reducing wind turbine blade rain erosion, which can accurately control the wind turbine speed to reduce rain erosion damage, while minimizing the loss of power generation, and providing technical support for the subsequent protection of the leading edge of large wind turbine blades.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for reducing rain erosion on blades includes the following steps:

[0007] Step 1: The sensor monitors the impact force of raindrops on the blade surface in real time;

[0008] Step 2: Establish the impact force P i -Damage D i The database, along with the number of rainfall days within the design life of the local wind farm, is used to formulate unit control damage values;

[0009] Step 3: Combine the unit control damage value and the current damage value to control the wind turbine speed;

[0010] Step 4: The data acquisition device counts the cumulative damage of the current blade. When the cumulative damage reaches the total damage, a fault warning for blade rain erosion is issued.

[0011] Alternatively, the sensor may be a piezoelectric impact sensor.

[0012] Alternatively, the sensor monitoring data can be calibrated to eliminate the influence of rotational speed and wind speed on the sensor.

[0013] Alternatively, in step 1, the leading edge of the blade may be monitored.

[0014] Alternatively, in step 2, the relationship between raindrop impact force and fatigue damage to the leading edge protective film or paint of the blade is established using the finite element method, and the impact force P is formed. i -Damage D i The database.

[0015] Alternatively, test data based on rain erosion experiments can be used as a standard to measure rain erosion damage at the blade leading edge, and the total damage D can be established through database interpolation. total =1;

[0016] Based on the total number of rainfall hours n within the target design life of the local wind field, the total damage is allocated to the 1-hour control unit D1 as the initial damage:

[0017]

[0018] Where D1 is the initial target damage value of the control unit, and n is the total number of hours of rainfall.

[0019] Alternatively, the target design life is 25 years.

[0020] Alternatively, an impact force P can be collected from the leading edge of the blade using a piezoelectric impact sensor. i -Damage D i The database interpolates damage in real time, and uses a data collector to accumulate all damage up to this moment, aggregating it hourly. j Redefine the damage value in the element based on the current damage:

[0021]

[0022] Among them, D k P represents the target damage value for the current control unit. j Let be the damage value during the j-th hour of rainfall, where j is the current cumulative number of hours of rainfall.

[0023] Alternatively, in step 3, according to the redefined D k To control the target, examine the impact force P. i -Damage D i The database dynamically reduces wind speed and rotational speed to ensure the current damage value does not exceed D. k This enables real-time control of the unit.

[0024] A monitoring device for reducing blade rain erosion includes a piezoelectric impact sensor located at the leading edge of the blade. The piezoelectric impact sensor is connected to a main control system via a data acquisition unit. The main control system is connected to a converter and a monitoring system.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] 1. The method and monitoring equipment for reducing wind turbine blade erosion provided by the present invention can reduce the impact of raindrops on wind turbine blades, thereby improving the operating performance of wind turbine units, extending the service life of blades and reducing maintenance costs.

[0027] 2. The present invention provides a method and monitoring device for reducing blade rain erosion, which uses a piezoelectric impact sensor to test the impact of raindrops on the blade tip and measures the impact force P. i -Damage D i The damage is retrieved from the database table. If it exceeds the damage value of the control unit, the wind turbine speed will be adjusted to reduce the wind turbine speed so that the damage is less than the damage value of the control unit, thereby achieving more precise control of rain erosion damage. Attached Figure Description

[0028] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0029] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings.

[0031] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0032] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0033] One method to reduce blade rain erosion, such as Figure 1 As shown, it includes the following steps:

[0034] Step 1: The sensor monitors the impact force of raindrops on the blade surface in real time;

[0035] Step 2: Establish the impact force P based on the blade leading edge protection method. i -Damage D iThe database, along with the number of rainfall days within the design life of the local wind farm, is used to formulate unit control damage values;

[0036] Step 3: Combine the unit control damage value and the current damage value to control the wind turbine speed;

[0037] Step 4: Use a data acquisition device to count the cumulative damage to the blades and provide early warning of blade rain erosion.

[0038] Specifically, raindrops possess kinetic energy during their descent. When they impact the blade surface at a certain speed, especially when striking a rotating blade, they cause physical impact. This impact force may create dents, cracks, or other forms of damage on the blade surface. It also generates mechanical forces such as friction and shear forces. These forces may cause coatings, adhesives, or other protective layers on the blade surface to peel off, exposing the blade substrate and accelerating material wear and corrosion. Furthermore, the acidic substances and salts in raindrops may undergo chemical reactions upon contact with the blade material, such as corrosion and hydrolysis, which, over time, weaken the blade's structure and performance. However, the blade rotation speed is directly related to the power generation efficiency of the wind turbine. Too low a rotation speed leads to a decrease in the generator's output power, reducing power generation and impacting the economics of the wind farm. Therefore, while reducing the rotation speed to mitigate raindrop impact, it is necessary to ensure that the rotation speed does not decrease to a level that negatively affects power generation efficiency; a balance needs to be found between protecting the blade and maintaining power generation efficiency. This method establishes an impact force P... i -Damage D i By using a database and controlling the blade rotation speed within a target range based on unit control damage values ​​and current damage values, the system can reduce blade tip speed, decrease the speed at which raindrops impact the blades, thereby reducing impact force, lowering the leading-edge corrosion rate, and extending blade lifespan. It also ensures the blades maintain optimal aerodynamic performance, allowing them to capture more wind energy even at lower wind speeds and maintain efficient energy conversion. Furthermore, by collecting data from sensors, accurate damage values ​​can be obtained, enabling timely detection and handling of rain erosion issues, further extending blade lifespan and reducing the frequency and cost of blade replacement. This also helps ensure the blades operate in optimal condition, maintaining high power generation efficiency and preventing a decrease in wind turbine efficiency, which could lead to energy loss and reduced revenue.

[0039] In another specific implementation, the sensor is a piezoelectric impact sensor. Piezoelectric impact sensors have high sensitivity and can detect minute changes in impact force, thereby accurately monitoring information such as the size, shape, and velocity of raindrops.

[0040] As another specific implementation method, the sensor monitoring data is calibrated to eliminate the influence of rotational speed and wind speed on the sensor. When monitoring the impact force of raindrops, rotational speed and wind speed can affect the actual impact force of the raindrops. By eliminating the influence of rotational speed and wind speed, the accuracy and stability of the sensor monitoring results can be ensured, allowing for a more accurate assessment of the potential damage of raindrops to the blades and the implementation of appropriate protective measures.

[0041] In another specific implementation, step 1 involves monitoring the leading edge of the blade. During blade rotation, the blade tip has the highest linear velocity, meaning raindrops possess significant kinetic energy upon impact, increasing the potential for rain erosion damage. Furthermore, the leading edge of the blade is typically designed to be sharp or have a specific geometry to optimize aerodynamic performance. This design results in a greater impact force when raindrops strike the leading edge, especially near the blade tip. This makes the leading edge more susceptible to rain erosion than other parts, thus requiring special attention and effective protection and monitoring.

[0042] As another specific implementation, in step 2, the relationship between the raindrop impact force and the fatigue damage of the blade leading edge protective film or paint is established using the finite element method, and the impact force P is formed. i -Damage D i The database. The finite element method can simulate various physical phenomena and engineering behaviors, including stress, strain, and stiffness of mechanical structures. Therefore, the finite element method is used to analyze impact force P. i -Damage D i The database can consider various mechanical actions to obtain the impact force P. i -Damage D i The experimental data provides the original data source for establishing the database.

[0043] As another specific implementation method, based on the test data from rain erosion tests, and using this data as a standard to measure rain erosion damage at the blade leading edge, a total damage D is established through database interpolation. total =1;

[0044] Based on the total number of rainfall hours n within the target design life of the local wind field, the total damage is allocated to the 1-hour control unit D1 as the initial damage:

[0045]

[0046] Where D1 is the initial target damage value of the control unit, and n is the total number of hours of rainfall.

[0047] Breaking down the total damage into hourly damage allows for a more accurate description of the damage situation. Rotation speed is then controlled based on this damage level to ensure that the actual damage is less than this value, thus guaranteeing that the blades reach their expected service life.

[0048] As another specific implementation, the target design life is 25 years.

[0049] As another specific implementation method, the impact force at the leading edge of the blade is collected based on a piezoelectric impact sensor, and the impact force P is used... i -Damage D i The database interpolates damage in real time, and uses a data collector to accumulate all damage up to this moment, aggregating it hourly. j Redefine the damage value in the element based on the current damage:

[0050]

[0051] Among them, D k D represents the target damage value for the current control unit. j Let be the damage value during the j-th hour of rainfall, where j is the current cumulative number of hours of rainfall.

[0052] Specifically, dividing the total damage over the target service life into hourly damage is only a preliminary framework and assumption. In reality, the hourly damage value may not be the same. Therefore, it is necessary to revise the target damage value of the control unit based on the actual cumulative damage. This allows for precise statistical analysis of actual damage details and improves the accuracy of life prediction results.

[0053] As another specific implementation, in step 3, according to the redefined D k To control the target, examine the impact force P. i -Damage D i The database dynamically reduces wind speed and rotational speed to ensure the current damage value does not exceed D. k This enables real-time control of the wind turbine unit. Reducing the rotational speed of the wind turbine blades decreases the relative velocity of raindrops upon contact with the blades, thus reducing the impact force. Furthermore, the lower velocity reduces the shear and frictional forces generated when raindrops impact the blades, further lowering the overall impact force. Real-time calculation and feedback ensure the accuracy of the control target, thereby guaranteeing the actual lifespan. Moreover, the rotational speed control can be adjusted based on real-time monitoring by a piezoelectric impact sensor.

[0054] A monitoring device for reducing wind turbine blade erosion includes a piezoelectric impact sensor located at the leading edge of the blade. The piezoelectric impact sensor is connected to a main control system via a data acquisition unit. The main control system is connected to a converter and a monitoring system. Specifically, all of the above connections are communication connections. The piezoelectric impact sensor is connected to the data acquisition unit, which in turn connects to the main control system. The main control system controls the wind turbine speed via the converter or provides fault warnings via the monitoring system.

[0055] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for reducing rain erosion on blades, characterized in that: Includes the following steps: Step 1: The sensor monitors the impact force of raindrops on the blade surface in real time and monitors the leading edge of the blade. Step 2, Establish Impact Force -damage Based on the database and the number of rainfall days within the design life of the local wind farm, unit control damage values ​​were formulated. The finite element method was used to establish the relationship between raindrop impact force and fatigue damage of the leading edge protective film or paint on the blade, and the impact force was formed. -damage The database; Step 3: Combine the unit control damage value and the current damage value to control the wind turbine speed; Step 4: The data acquisition device counts the cumulative damage of the current blade. When the cumulative damage reaches the total damage, a fault warning for blade rain erosion is issued.

2. The method for reducing blade rain erosion as described in claim 1, characterized in that: The sensor is a piezoelectric impact sensor.

3. The method for reducing blade rain erosion as described in claim 1, characterized in that: The sensor monitoring data is calibrated to eliminate the influence of rotational speed and wind speed on the sensor.

4. The method for reducing blade rain erosion as described in claim 1, characterized in that: Based on test data from rain erosion experiments, and using this data as a standard to measure rain erosion damage at the blade leading edge, a total damage assessment was established through database interpolation. =1; Based on the total number of rainfall hours n within the target design life of the local wind field, the total damage is allocated to the 1-hour control unit. As initial damage: in, is the initial target damage value for the control unit, and n is the total number of hours of rainfall.

5. The method for reducing blade rain erosion as described in claim 4, characterized in that: The target design life is 25 years.

6. The method for reducing blade rain erosion as described in claim 4, characterized in that: The impact force at the leading edge of the blade is collected using a piezoelectric impact sensor, and the impact force is then utilized. -damage The database interpolates damage in real time, and the data collector accumulates all damage up to that moment, aggregating it hourly. Redefine the damage value in the element based on the current damage: in, The target damage value for the current control unit. Let be the damage value during the j-th hour of rainfall, where j is the current cumulative number of hours of rainfall.

7. The method for reducing blade rain erosion as described in claim 6, characterized in that: In step 3, according to the redefined To control the target, observe the impact force. -damage The database dynamically reduces wind speed and rotational speed to ensure that the current damage value does not exceed [the specified value]. This enables real-time control of the unit.

8. A monitoring device for reducing rain erosion on blades, characterized in that: It includes a piezoelectric impact sensor located at the leading edge of the blade. The piezoelectric impact sensor is connected to a main control system via a data acquisition unit. The main control system is connected to a converter and a monitoring system.

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