Wake detection method and system based on blade clearance and wind turbine rotational speed

Abstract

The present application relates to a kind of based on blade clearance and wind wheel rotating speed's wake detection method and system, the method includes: based on the wide-angle camera vertically installed below cabin to the state of wind turbine when running image shooting, obtain the clearance detection picture of wind turbine blade at different running time;Clearance detection picture is handled, and clearance data is calculated;From clearance detection video processing or SCADA, obtain the rotating speed data of wind wheel rotor, calculate its average value and fluctuation value;Based on the clearance data and the average value and fluctuation value of calculated rotating speed, under wind speed, turbulence, wind cut, air density, variable pitch angle, different wake coverage interference, the average data of blade clearance, rotating speed and the fluctuation data multidimensional table, i.e. wake coverage multidimensional table is established;In the process of wind turbine operation, corresponding wake coverage situation is found out by inquiring wake coverage multidimensional table.The present application solves the problem of difficult inspection and repair, reduces the blade failure rate, can timely early warning blade failure, realizes real-time wake control, reduces wake interference.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of offshore wind farm wind turbine wake interference detection, and particularly relates to a wake detection method and system based on blade clearance and wind wheel rotating speed. BACKGROUND

[0002] Offshore wind energy resources are abundant, wind speed is high, turbulence is small, and power generation is large, and developing offshore wind power does not occupy land resources, which provides favorable conditions for the development of offshore wind power. However, due to the more severe environment of offshore wind farms, the cost of wind farms is very high. How to ensure the safe and efficient operation of the wind turbine and improve the service life of the wind turbine is the focus of current operation and maintenance. Since the turbulence intensity of offshore wind farms is lower than that on land, the wake of offshore wind farms is more difficult to dissipate, and the downwind wind turbine is more seriously affected by the wake than on land. Wake interference will cause the power of the wind farm to decrease, the fatigue load of the wind turbine to increase, and the service life of the wind turbine to decrease greatly. And the wake interference will cause the clearance fluctuation of the blade to increase, especially the faulty blade under the influence of the wake even occurs tower scanning event, which seriously threatens the safe and efficient operation of the offshore wind farm and causes huge economic losses. SUMMARY

[0003] The purpose of the present application is to provide a wake detection method and system based on blade clearance and wind wheel rotating speed to improve the intelligent safety monitoring of offshore wind farm wind turbine impeller and power generation profitability.

[0004] The present application provides a wake detection method based on blade clearance and wind wheel rotating speed, comprising the following steps:

[0005] Step 1: Based on the wide-angle camera vertically installed below the cabin, the state of the wind turbine during operation is imaged to obtain the clearance detection picture of the wind turbine blade at different operating times;

[0006] Step 2: The clearance detection picture in step 1 is processed to calculate the clearance data; the wind wheel rotor speed data is obtained from the clearance detection video processing or SCADA data, and the average value and fluctuation value thereof are calculated;

[0007] Step 3: Based on the calculated clearance data and the average value and fluctuation value of the rotating speed, under the conditions of wind speed, turbulence, wind shear, air density, and variable pitch angle, a multi-dimensional table of blade clearance, average data and fluctuation data of rotating speed under different wake coverage interference is established, that is, a wake coverage multi-dimensional table;

[0008] Step 4: During the operation of the wind turbine, the corresponding wake coverage condition is found out by querying the wake coverage multi-dimensional table.

[0009] Further, the processing of the clearance detection picture in step 1 to calculate the clearance data in step 2 includes:

[0010] The image is preprocessed to obtain a clear and easy-to-calculate clearance picture gray image, the image is binarized and connected region labeled, the foreground target and the background are separated based on the connected region labeling, the edge detection is performed on the tower drum and the blade to obtain a clear edge, the tip point and the tower drum point detection is performed, the clearance distance when the fan is running is calculated, the clearance distance detection is performed on all the pictures obtained by shooting, the minimum clearance distance at different time is obtained, the minimum clearance distance is extracted and the average value is calculated, and the clearance data is obtained.

[0011] The application also provides a wake detection system based on blade clearance and wind wheel speed, comprising:

[0012] A wide-angle camera module is vertically installed below the cabin and is used for image shooting of the state when the fan is running to obtain clearance detection pictures of the fan blades at different running time;

[0013] A calculation module is used for processing the clearance detection pictures to calculate the clearance data, obtaining the wind wheel rotor speed data from the clearance detection video processing or the SCADA data, and calculating the average value and fluctuation value thereof;

[0014] A wake coverage multi-dimensional table establishing module is used for establishing a multi-dimensional table of the average data and fluctuation data of the blade clearance and speed based on the calculated clearance data and the average value and fluctuation value of the speed under different wake coverage interference of wind speed, turbulence, wind shear, air density and variable pitch angle, i.e., a wake coverage multi-dimensional table;

[0015] A query module is used for finding out the corresponding wake coverage situation by querying the wake coverage multi-dimensional table during the running of the fan.

[0016] Further, the calculation module pre-processes the image to obtain a clear and easy-to-calculate clearance picture gray image, binarizes and labels the connected region of the image, separates the foreground target and the background based on the connected region labeling, performs edge detection on the tower drum and the blade to obtain a clear edge, performs tip point and tower drum point detection, calculates the clearance distance when the fan is running, performs clearance distance detection on all the pictures obtained by shooting, obtains the minimum clearance distance at different time, extracts the minimum clearance distance and calculates the average value, and obtains the clearance data.

[0017] Through the wake detection method and system based on the blade clearance and the wind wheel speed, the clearance is analyzed online, the difficulty problem of the inspection and repair is solved, the blade failure rate is reduced, the blade failure can be timely warned, the wake interference system corrects the wake model based on the clearance and the wind wheel speed, the wake interference can be accurately captured in real time, the real-time wake control is realized, and the wake interference is reduced.

[0018] The above description is only a summary of the technical scheme of the present application. In order to make the technical means of the present application clearer and can be implemented according to the content of the description, the preferred embodiments of the present application are described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a flow chart of the wake detection method based on blade clearance and wind wheel speed of the present application;

[0020] Figure 2 is a structural block diagram of the wake detection system based on blade clearance and wind wheel speed of the present application. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application are described in further detail below in combination with the drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0022] Referring to Figure 1 The present embodiment provides a wake detection method based on blade clearance and wind wheel speed, which includes the following steps:

[0023] Step S1, based on the wide-angle camera vertically installed below the nacelle, the state of the wind turbine during operation is imaged to obtain the clearance detection picture of the wind turbine blade at different operating times. Turbulence increase is one of the important characteristics of wake, which causes the tip clearance fluctuation to become larger. A wide-angle camera is installed vertically downward below the nacelle, the camera is calibrated, the position of itself is located, it is ensured that the tower drum and the blade during operation are all within the image field of view, and the state of the wind turbine during operation is imaged by the wide-angle camera to obtain the working state picture of the wind turbine blade at different operating times, so as to obtain the wind turbine picture that can be used for clearance monitoring. The way of imaging the blade clearance by the camera can effectively obtain the health state of the blade and ensure the detection of the operating state of the blade.

[0024] Step S2, the clearance detection picture in step S1 is processed to calculate the clearance data; the rotor speed data of the wind wheel is obtained from the clearance detection video processing or the SCADA data, and the average value and the fluctuation value are calculated. In a specific example, the data of the blade clearance obtained from image processing is calculated to obtain the average value and the standard deviation. The blade clearance and the rotor data during 5 minutes of operation of the wind turbine are taken, and the average value and the standard deviation are taken respectively. The wake interference condition can be effectively obtained by the clearance data, the wake interference is captured in time, the calibration basis is provided for the wake model, and the real-time guarantee is provided for the wake control.

[0025] Step S3, based on the calculated clearance data, the average value and the fluctuation value of the speed, the turbulence, the wind shear, the air density, the variable pitch angle, and the different wake coverage interference, a multi-dimensional table of the average data and the fluctuation data of the blade clearance and the speed, i.e. a wake coverage multi-dimensional table, is established.

[0026] In a specific example, high-fidelity software is used to simulate the wind farm wake interference, and the mean and fluctuation of the blade clearance and the speed are obtained under different factors. The considered factors are: wind speed, turbulence intensity, wind shear, air density, variable pitch angle, wake coverage.

[0027] Wind speed:

[0028] 6m / s, 6.5m / s, 7m / s, 7.5m / s, 8m / s, 8.5m / s, 9m / s, 9.5m / s, 10m / s, 10.5m / s.

[0029] Wind shear: 1.2, 1.4, 1.6, 1.8, 2.0.

[0030] Air density: 1.224, 1.1 (Kg / m 3 ).

[0031] Variable pitch angle: 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6.

[0032] Wake coverage:

[0033] 1, 1 / 8, 2 / 8, 3 / 8, 4 / 8, 5 / 8, 6 / 8, 7 / 8, -1 / 8, -2 / 8, -3 / 8, -4 / 8, -5 / 8, -6 / 8, -7 / 8.

[0034] Step S4, during the operation of the wind turbine, the corresponding wake coverage is found by querying the multi-dimensional wake coverage table.

[0035] In this embodiment, the processing and calculation of the clearance data of the clearance detection picture in step S1 in step S2 include:

[0036] The image is preprocessed (including RGB to HSV, Gaussian filtering, image enhancement and other operations) to obtain a clearer and easier to calculate clearance picture gray image. The image is binarized and connected region labeled, the foreground target and background are separated based on the connected region labeling, the edges of the tower and the blades are detected to obtain clear edges, the blade tip point and the tower point (a point on the surface of the tower parallel to the blade tip) are detected, and the clearance distance during the operation of the wind turbine is calculated. The clearance distance of all the pictures obtained by shooting is detected to obtain the minimum clearance distance at different times. The minimum clearance distance is extracted and the average value is calculated to obtain the clearance data.

[0037] In a specific example, the captured image is first subjected to image preprocessing such as Gaussian blur and image enhancement, and then the obtained image is subjected to grayscale binarization to lay the foundation for subsequent edge detection of the edge straight line of the tower drum blade. Then, line fitting is performed to obtain the positions of the blade tip point and the tower drum point so as to calculate the clearance distance. The captured images are subjected to clearance distance detection to obtain the minimum clearance distance at different time points. The minimum clearance distance is extracted and the average value is calculated to obtain the clearance data.

[0038] Through the wake detection method based on the blade clearance and the wind wheel speed, the clearance is analyzed online, the difficulty of inspection and maintenance is solved, the blade failure rate is reduced, and the blade failure can be timely warned. The detection of the wake interference system based on the clearance and the wind wheel speed corrects the wake model, can accurately capture the wake interference in real time, realizes real-time wake control, and reduces the wake interference.

[0039] Referring to Figure 2 The embodiment also provides a wake detection system based on a blade clearance and a wind wheel speed, which comprises:

[0040] A wide-angle camera module 10 is vertically installed below the cabin and is used for image capturing of the state of the wind turbine during operation to obtain clearance detection images of the wind turbine blades at different operation time points;

[0041] A calculation module 20 is used for processing the clearance detection images and calculating the clearance data. The wind wheel rotor speed data is obtained from the clearance detection video processing or the SCADA data, and the average value and the fluctuation value thereof are calculated.

[0042] A wake coverage multi-dimensional table establishing module 30 is used for establishing a multi-dimensional table of the average data and the fluctuation data of the blade clearance and the speed based on the calculated clearance data and the average value and the fluctuation value of the speed under different wake coverage interference conditions of the wind speed, the turbulence, the wind shear, the air density and the variable pitch angle, that is, a wake coverage multi-dimensional table.

[0043] A query module 40 is used for finding out the corresponding wake coverage condition by querying the wake coverage multi-dimensional table during the operation of the wind turbine.

[0044] In the embodiment, the calculation module 20 pre-processes the image to obtain a clear and easy-to-calculate clearance image gray image. The image is binarized and connected region labeled. The foreground target and the background are separated based on the connected region labeling. The tower drum and the blade are subjected to edge detection to obtain clear edges. The blade tip point and the tower drum point are detected. The clearance distance during the operation of the wind turbine is calculated. The captured images are subjected to clearance distance detection to obtain the minimum clearance distance at different time points. The minimum clearance distance is extracted and the average value is calculated to obtain the clearance data.

[0045] Through the wake detection system based on the blade clearance and the wind wheel rotating speed, the clearance analysis is monitored online, the difficulty problem of the inspection and repair is solved, the blade failure rate is reduced, and the blade failure can be timely warned. The detection wake interference system based on the clearance and the wind wheel rotating speed corrects the wake model, can accurately capture the wake interference in real time, realizes real-time wake control, and reduces the wake interference.

[0046] The above only describes the preferred embodiments of the present application and is not used to limit the present application. It should be noted that, for ordinary skilled persons in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A wake detection method based on blade clearance and rotor speed, characterized in that, Includes the following steps: Step 1: Take images of the wind turbine's operating status using a wide-angle camera vertically installed below the nacelle to obtain headroom detection images of the wind turbine blades at different operating times. Step 2: Process the clearance detection images from Step 1 and calculate the clearance data; Obtain wind turbine rotor speed data from clearance detection video processing or SCADA data, and calculate its average value and fluctuation value; The calculation of clearance data includes: preprocessing the image to obtain a clear and easily calculable grayscale image of the clearance image; binarizing the image and marking connected components; separating the foreground target and background based on the connected component markings; performing edge detection on the tower and blades to obtain clear edges; performing blade tip and tower point detection; calculating the clearance distance during wind turbine operation; performing clearance distance detection on all captured images to obtain the minimum clearance distance at different times; extracting the minimum clearance distance and calculating the average value to obtain the clearance data. Step 3: Based on the calculated headroom data and the average and fluctuation values ​​of the rotational speed, establish a multidimensional table of the average data and fluctuation data of the blade headroom and rotational speed under the interference of wind speed, turbulence, wind shear, air density, pitch angle and different wake coverage surfaces, i.e., a wake coverage multidimensional table. Step 4: During the operation of the wind turbine, the corresponding wake coverage area is found by querying the wake coverage multidimensional table.

2. A wake detection system based on blade clearance and rotor speed, characterized in that, include: The wide-angle camera module is vertically installed below the nacelle and is used to capture images of the wind turbine's operating status, obtaining clearance detection images of the wind turbine blades at different operating times; The calculation module is used to process the clearance detection images and calculate the clearance data. Obtain wind turbine rotor speed data from clearance detection video processing or SCADA data, and calculate its average value and fluctuation value; The calculation of clearance data includes: preprocessing the image to obtain a clear and easily calculable grayscale image of the clearance image; binarizing the image and marking connected components; separating the foreground target and background based on the connected component markings; performing edge detection on the tower and blades to obtain clear edges; performing blade tip and tower point detection; calculating the clearance distance during wind turbine operation; performing clearance distance detection on all captured images to obtain the minimum clearance distance at different times; extracting the minimum clearance distance and calculating the average value to obtain the clearance data. The wake coverage multidimensional table creation module is used to create a multidimensional table of blade clearance, average speed and its fluctuation data based on calculated headroom data and average and fluctuation values ​​under wind speed, turbulence, wind shear, air density, pitch angle and different wake coverage surface interference, i.e. wake coverage multidimensional table. The query module is used to find the corresponding wake coverage area by querying the wake coverage multidimensional table during wind turbine operation.

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