A safety risk warning method for blade tower sweeping of large megawatt wind turbines

Abstract

The present invention provides a method for warning of the safety risk of blade tower sweeping in large megawatt wind turbine units, which relates to the technical field of blade tower sweeping warning. The purpose is to realize the monitoring of the blade trajectory through the installation of simple equipment, and at the same time realize accurate warning of blade tower sweeping, improve the monitoring quality, reduce the cost, reduce the accident probability and improve the safety of the wind turbine. It includes collecting the clearance distance of each blade in the wind turbine within a period T, and recording the moment of clearance distance collection while collecting the clearance distance each time; periodically collecting the vibration amplitude of the wind turbine and the acceleration of the wind turbine within the period T; obtaining the average offset of the clearance distance of each blade in the wind turbine and the minimum clearance distance of each blade within the period T; obtaining the maximum blade deformation degree of the wind turbine within the period T according to the vibration amplitude; obtaining the maximum blade deformation degree of the wind turbine within the period T according to the acceleration; predicting whether there is a risk of blade tower sweeping. The present invention has the advantages of low cost and accurate prediction.

Description

Technical Field

[0001] The present invention relates to the technical field of blade tower sweeping warning, and in particular, to a method for warning of safety risks of blade tower sweeping of large megawatt wind turbines. Background Art

[0002] Nowadays, the world's wind power has entered a stage of rapid development. In order to capture more wind energy from the environment, in recent years, the overall development trend of wind turbines has been towards large-scale and offshore directions, and the research focus of various countries has shifted to the design and development of large wind turbines with greater power, longer rotor diameters, lighter blade masses, and higher tower heights.

[0003] However, in the process of the development of large-scale and lightweight wind turbine blades, a series of problems have gradually emerged. Due to the incomplete mastery of the design of large blades by some manufacturers, the dynamic problems such as geometric nonlinearity, aeroelasticity, resonance, and instability of some blades have become increasingly prominent; the flexible control requirements brought about by the multi-system coupling of the turbine blades, tower, transmission chain, etc. have increased the difficulty of the design of the turbine control system; the site selection during the project construction period is not standardized, and the load adaptability of some wind turbines in the wind farm does not meet the design standards; during the rush installation period, the manufacturing, transportation, and hoisting of the blades are not standardized, resulting in invisible damage to the blades, and the long-term operation of the blades with diseases has exacerbated the fatigue damage of the blades. This series of problems will directly affect the safe operation of the unit, and most of the units with design and manufacturing defects have experienced the situation of blade tower sweeping after grid connection. The research on the key technologies for the safety risk assessment and prevention of blade tower sweeping of large megawatt wind turbines has become a very urgent task, but the monitoring of the movement trajectory of the wind turbine blades is actually quite difficult, and usually requires large-scale scanning observation or the installation and cooperation of multiple sensors.

[0004] If it is possible to monitor the blade trajectory through the installation of simple equipment and at the same time achieve accurate warning of blade tower sweeping, it will greatly improve the monitoring quality, reduce costs, and prevent tower sweeping risks. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for warning of safety risks of blade tower sweeping of large megawatt wind turbines, and its purpose is to monitor the blade trajectory through the installation of simple equipment and at the same time achieve accurate warning of blade tower sweeping, improve the monitoring quality, reduce costs, reduce the accident probability, and improve the safety of the wind turbine unit.

[0006] The embodiments of the present invention are implemented through the following technical solutions:

[0007] A method for warning of safety risks of blade tower sweeping of large megawatt wind turbines includes the following steps:

[0008] Collect the clearance distance of each blade in the wind rotor within a period T, and record the moment of clearance distance collection each time the clearance distance is collected;

[0009] Periodically collect the vibration amplitude and acceleration of the wind turbine within the period T;

[0010] Obtain the average offset of the clearance distance of each blade in the wind turbine within the period T and the minimum clearance distance of each blade

[0011] Obtain the maximum blade deformation degree d of the wind turbine within the period T according to the vibration amplitude AM ;

[0012] Obtain the maximum blade deformation degree d of the wind turbine within the period T according to the acceleration AC ;

[0013] According to d AM and d AC Predict whether there is a risk of blade tower sweeping.

[0014] Preferably, the method for collecting the clearance distance of each blade in the wind turbine is as follows:

[0015] Set an ultrasonic sensor and a counter;

[0016] Install the ultrasonic sensor outside the nacelle of the wind power generation unit. When the wind turbine rotates, the blade trajectory forms a circular trajectory, and the detection end of the ultrasonic sensor faces any point inside the circular trajectory and close to the edge of the circular trajectory;

[0017] Initialize the value of the counter m = 0;

[0018] When the wind turbine starts to rotate, each time the ultrasonic sensor detects an obstacle in front, the value of the counter m is incremented by 1 and the distance L of the obstacle at this time is recorded m , and finally obtain the array L measure = [L1, L2, …, L M ;

[0019] Obtain the number N of blades in the wind turbine;

[0020] Obtain the array L formed by the clearance distance of the i-th blade collected in time series within the period T measure-i :

[0021]

[0022] Preferably, the method for obtaining the average offset of the clearance distance of each blade in the wind turbine within the period T is as follows:

[0023] Obtain the clearance distance of each blade in the wind turbine in a stationary state

[0024] Average offset of the clearance distance of blade No. i in the wind turbine is:

[0025]

[0026] wherein, is the clearance distance of blade No. i in the stationary state, and L measure-i is an array formed by the clearance distances of blade No. i collected in chronological order within the period T, and the total number of elements in the array is N i , is the k-th element in L measure-i .

[0027] Preferably, the method for obtaining the minimum clearance distance of each blade is:

[0028]

[0029] Preferably, the method for obtaining the deformation degree of the blade with the largest vibration is:

[0030] Obtain the moment t1 corresponding to the maximum vibration amplitude of the wind turbine within the period T;

[0031] Among the clearance distance collection moments, obtain the N moments closest to the moment t1 and the corresponding collected clearance distances. These clearance distances form an array A, and N is the total number of blades of the wind turbine;

[0032] Obtain the deformation degree d AM :

[0033] d AM = max(A) - min(A).

[0034] Preferably, the method for obtaining the deformation degree of the blade with the largest acceleration is:

[0035] Obtain the moment t2 corresponding to the maximum acceleration of the wind turbine within the period T;

[0036] Among the clearance distance collection moments, obtain the N moments closest to the moment t2 and the corresponding collected clearance distances. These clearance distances form an array B, and N is the total number of blades of the wind turbine;

[0037] Obtain the deformation degree d AC :

[0038] d AC = max(B) - min(B).

[0039] Preferably, the method for predicting whether there is a risk of blade tower collision is that if any of the following conditions is met, it is considered that there is a risk of blade tower collision:

[0040] The changing trend of the clearance distance of the blade poses a risk of tower collision;

[0041] The degree of deformation of the blade poses a risk of tower collision.

[0042] Preferably, the judgment criterion for the changing trend of the clearance distance of the blade posing a risk of tower collision is: the average deviation of the clearance distance of any one of the blades exceeds the speed threshold, or the minimum clearance distance of any one of the blades is lower than the minimum distance threshold.

[0043] Preferably, the judgment criterion for the degree of deformation of the blade posing a risk of tower collision is:

[0044] Obtain the judgment parameter d p : d p = d AM + d AC ;

[0045] The judgment parameter d p being greater than the judgment threshold indicates that the degree of deformation of the blade poses a risk of tower collision.

[0046] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0047] By monitoring the blades of the wind turbine generator set, the present invention conducts intelligent early warning of the tower collision of the blades of the wind turbine generator set through the prediction of the clearance distance, improves the safety of the wind turbine generator set, and reduces the accident probability caused by the tower collision of its blades;

[0048] The present invention realizes the operation monitoring of all the fan blades through one monitoring device, and the monitoring device does not need to be installed on the blade, which has stronger stability and high cost performance at the same time;

[0049] The present invention also monitors the change of the clearance distance of each blade, which is convenient for comparing the differences between different fan blades, and better monitors the tower collision risk of the blade as a parameter;

[0050] The present invention obtains a variety of parameters through monitoring as the standard for early warning the tower collision risk of the blade, and the monitoring is more comprehensive, which helps to improve the quality of the tower collision early warning of the blade;

[0051] The present invention is reasonably designed, the relevant data processing and operation process are simple, the computing power and the installation cost of the relevant device are low, and it is convenient for popularization and application. Description of the Drawings

[0052] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0053] Figure 1 It is a schematic flowchart of a method for warning of the safety risk of blade tower sweeping in a large megawatt wind turbine provided in Embodiment 1 of the present invention;

[0054] Figure 2 It is a schematic diagram of the installation position of an ultrasonic sensor provided in Embodiment 2 of the present invention. Specific Embodiments

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0057] Embodiment 1

[0058] Refer to Figure 1 , this embodiment provides a method for warning of the safety risk of blade tower sweeping in a large megawatt wind turbine, including the following steps:

[0059] Step S1: Collect the clearance distance of each blade in the wind turbine within a period T, and record the clearance distance acquisition time each time the clearance distance is collected;

[0060] Step S2: Periodically collect the vibration amplitude and acceleration of the wind turbine within a period T;

[0061] Step S3: Obtain the average offset of the clearance distance of each blade in the wind turbine within a period T and the minimum clearance distance of each blade

[0062] Step S4: Obtain the maximum blade deformation degree d of the wind turbine within a period T according to the vibration amplitude AM ;

[0063] Step S5: Obtain the maximum blade deformation degree d of the wind turbine within the period T according to the acceleration AC ;

[0064] Step S6: Predict whether there is a risk of blade tower sweeping according to d AM and d AC Predict whether there is a risk of blade tower sweeping

[0065] The basic execution idea of this embodiment is as follows:

[0066] On the one hand, in this embodiment, by collecting the clearance distance of each blade, the average offset of the clearance distance of each blade in the wind turbine within the period T is obtained and the minimum clearance distance of each blade Both of these parameters can be used as important indicators for blade tower sweeping warning

[0067] On the other hand, collect the vibration amplitude of the wind turbine and the acceleration of the wind turbine, so as to obtain the moments when the vibration amplitude of the wind turbine is the largest and the acceleration of the wind turbine is the largest respectively, and then find the clearance distance of each blade at these times, so as to obtain the deformation of the blade. Excessive deformation can also be regarded as an important indicator for blade tower sweeping warning. The period of collecting the vibration amplitude of the wind turbine and the acceleration of the wind turbine can be determined by the rotation speed of the blade

[0068] Then, when there is a risk of blade tower sweeping, a warning can be issued in time, and subsequent operations such as automatically or by the staff reducing the operating power and stopping for inspection can be performed. Processing according to a period T is to facilitate data processing in a time period and avoid chaotic situations such as infinite increase and accumulation of data during the processing

[0069] It should be particularly noted that the specific data processing and judgment processes can be implemented by the control module, and the warning results can be transmitted to the remote end, such as remote consoles, remote computers, and mobile devices such as mobile phones

[0070] Embodiment 2

[0071] Based on the technical solution of Embodiment 1, this embodiment further describes the method for collecting the clearance distance of each blade in the wind turbine

[0072] In this embodiment, the method for collecting the clearance distance of each blade in the wind turbine is as follows:

[0073] Set ultrasonic sensors and counters

[0074] Install the ultrasonic sensor outside the nacelle of the wind turbine. When the wind turbine rotates, the blade trajectory forms a circular trajectory, and the detection end of the ultrasonic sensor faces any point inside the circular trajectory and close to the edge of the circular trajectory. For the schematic diagram of the specific installation position, please refer to Figure 2 , Figure 2 which is a side view. Here, A is the side of the circular trajectory formed by the blade trajectory, and B is the ultrasonic sensor;

[0075] Initialize the value of the counter m = 0;

[0076] When the wind turbine starts to rotate, every time the ultrasonic sensor detects an obstacle in front, the value of the counter m is incremented by 1 and the distance L of the obstacle at this time is recorded m , and finally an array L measure = [L1, L2, …, L M is obtained;

[0077] Obtain the number N of blades in the wind turbine;

[0078] Obtain the array L formed by the clearance distances of the i-th blade collected in chronological order within the period T measure-i :

[0079]

[0080] In an operating wind turbine, if one wants to track the clearance distance of a single blade, generally a sensor is set on each blade to collect data. However, the blades of the wind turbine are continuously rotating at a high speed, and it is very easy to throw the sensors on the blades out. If one wants to ensure the stability of the sensors, a special fixing structure needs to be set. Such installation consumes a large amount and will also add an extra burden to the wind turbine. In order to ensure the operation effect of the wind turbine, the design difficulty is also great.

[0081] Therefore, the advantages of this embodiment are as follows: Only one ultrasonic sensor and a counter are installed to realize the capture of the clearance distance of the blades of the wind turbine, and the recognition of blade switching is realized by using the gaps between the blades, and the total number of blades captured within the period T and the clearance distance of each captured blade are captured in cooperation with the counter. Since the number of blades of the wind turbine is known, it is very easy to group all the captured blades. As mentioned in the previous embodiment 1, the periods for collecting the vibration amplitude and acceleration of the wind turbine can be determined by the rotational speed of the blades. Based on the solution of this embodiment, the periods for collecting the vibration amplitude and acceleration of the wind turbine can be set so that the vibration sensor and the acceleration sensor also collect data every time the ultrasonic sensor captures data.

[0082] For example, a total of 100 times of blade data are captured. Given that the wind turbine has 3 blades, it can be easily known that discarding the last bit of data reduces the computational complexity and can also ensure that the number of times each blade is captured is the same. Here, a floor operation is performed, and each identical blade is captured The data captured at the 1st, 4th, 7th, …, 97th times can be regarded as the data of blade No. 1, the data captured at the 2nd, 5th, 8th, …, 98th times can be regarded as the data of blade No. 2, and the data captured at the 3rd, 6th, 9th, …, 99th times can be regarded as the data of blade No. 2. In this way, through a stable, easy-to-install, and cost-effective monitoring device, the change in the clearance distance of each single blade within the period T can be captured.

[0083] Embodiment 3

[0084] Based on the technical solution of Embodiment 1, this embodiment further illustrates the average offset of the clearance distance, etc.

[0085] As a preferred solution of this embodiment, the method for obtaining the average offset of the clearance distance of each blade in the wind turbine within the period T is as follows:

[0086] Obtain the clearance distance of each blade in the wind turbine in the stationary state

[0087] The average offset of the clearance distance of the i-th blade in the wind turbine is:

[0088]

[0089] where is the clearance distance of the i-th blade in the stationary state, and L measure-i is an array formed by the clearance distances of the i-th blade collected in chronological order within the period T, and the total number of elements in the array is N i , is the k-th element in L measure-i .

[0090] On the other hand, the method for obtaining the minimum clearance distance of each blade is as follows:

[0091]

[0092] In this embodiment, the following operations are performed on each blade respectively: taking the clearance distance in the stationary state of the blade as the standard clearance distance, extracting the clearance distance captured each time and then calculating the offset of this clearance distance from the standard clearance distance, and then accumulating and taking an average value to obtain the average offset; in addition, taking the minimum value in the clearance distance array of each blade can obtain the minimum clearance distance of each blade within the period T. The above two parameters are both important parameters for blade tower-scanning warning.

[0093] Embodiment 4

[0094] Based on the technical solution of Embodiment 1, this embodiment further illustrates the deformation degree of the blade with the largest vibration and the deformation degree of the blade with the largest acceleration.

[0095] Preferably, the method for obtaining the deformation degree of the blade with the largest vibration is as follows:

[0096] Obtain the moment t1 corresponding to the maximum vibration amplitude of the wind turbine within the period T;

[0097] Among the clearance distance acquisition moments, obtain the N moments closest to the moment t1 and the corresponding collected clearance distances. These clearance distances form an array A, where N is the total number of blades of the wind turbine;

[0098] Obtain the deformation degree d of the blade with the largest vibration AM :

[0099] d AM = max(A) - min(A).

[0100] In addition, the method for obtaining the deformation degree of the blade with the largest acceleration is as follows:

[0101] Obtain the moment t2 corresponding to the maximum acceleration of the wind turbine within the period T;

[0102] Among the clearance distance acquisition moments, obtain the N moments closest to the moment t2 and the corresponding collected clearance distances. These clearance distances form an array B, where N is the total number of blades of the wind turbine;

[0103] Obtain the deformation degree d of the blade with the largest vibration AC :

[0104] d AC = max(B) - min(B).

[0105] The specific idea of this embodiment is as follows:

[0106] Collect the vibration amplitude of the wind collecting rotor and the acceleration of the wind rotor, so as to obtain the moments when the vibration amplitude of the wind rotor is the largest and the acceleration of the wind rotor is the largest, which are t1 and t2 respectively. Then, find the clearance distances of each blade at the N moments closest to t1 and t2 respectively. The N closest moments must be N consecutive capture time points, and N is also the number of blades. Therefore, each of these N time points exactly captures the clearance distance of each of the N blades in the wind rotor once. And due to the high-speed rotation of the wind rotor, the actual N time points are very close to each other.

[0107] Through d AM and d AC When the maximum amplitude and maximum acceleration can be obtained respectively, the difference between the maximum clearance distance and the minimum clearance distance of the blades can be obtained. This difference is regarded as the deformation parameter, that is, the deformation of the blade is obtained in this way. Excessive deformation can also be regarded as an important indicator for early warning of blade tower sweeping.

[0108] Embodiment 5

[0109] Based on the technical solution of Embodiment 1, this embodiment further illustrates the specific risk prediction of blade tower sweeping.

[0110] In this embodiment, the method for predicting whether there is a risk of blade tower sweeping is as follows: Meeting any of the following conditions is regarded as having a risk of blade tower sweeping:

[0111] The change trend of the clearance distance of the blade has a risk of tower sweeping;

[0112] The degree of deformation of the blade has a risk of tower sweeping.

[0113] Among them, the judgment criterion for the change trend of the clearance distance of the blade having a risk of tower sweeping is: The average offset of the clearance distance of any blade exceeds the rate threshold, or the minimum clearance distance of any blade is lower than the minimum distance threshold.

[0114] On the other hand, the judgment criterion for the degree of deformation of the blade having a risk of tower sweeping is:

[0115] Obtain the judgment parameter d p : d p = d AM + d AC ;

[0116] If the judgment parameter d p is greater than the judgment threshold, then the degree of deformation of the blade has a risk of tower sweeping.

[0117] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for warning of safety risks of blade tower sweeping in large megawatt wind turbines, characterized in that, Including the following steps: Collect the clearance distance of each blade in the wind turbine within the period T, and record the moment when the clearance distance is collected each time the clearance distance is collected; Periodically collect the vibration amplitude of the wind turbine and the acceleration of the wind turbine within the period T; Obtain the average offset of the clearance distance of each blade in the wind turbine during the period T and the minimum clearance distance of each blade Obtain the maximum blade deformation degree d of the wind turbine within the period T according to the vibration amplitude AM ; Obtain the maximum blade deformation degree d of the wind turbine during the period T based on the acceleration AC ; According to d AM and d AC predict whether there is a risk of blade hitting the tower; The method for predicting whether there is a risk of blade tower collision is that if any of the following conditions is met, it is considered that there is a risk of blade tower collision: The change trend of the clearance distance of the blade has a risk of tower collision; The deformation degree of the blade has a risk of tower collision; The judgment criterion for the risk of tower sweeping due to the changing trend of the clearance distance of the blade is: the average deviation of the clearance distance of any blade exceeds the rate threshold, or the minimum clearance distance of any blade is lower than the minimum distance threshold; The judgment criterion for the deformation degree of the blade having a risk of tower collision is: Obtain the judgment parameter d p : d p = d AM + d AC ; Judge parameter d p If it is greater than the judgment threshold, there is a risk of tower sweeping in the deformation degree of the blade.

2. The method for warning of safety risks of blade tower sweeping of large megawatt wind turbines according to claim 1, wherein, The method for collecting the clearance distance of each blade in the wind turbine is: Set an ultrasonic sensor and a counter; Install the ultrasonic sensor outside the nacelle of the wind power generating set. When the wind turbine rotates, the blade trajectory forms a circular trajectory, and the detection end of the ultrasonic sensor is directly opposite to any point inside the circular trajectory and close to the edge of the circular trajectory; Initialize the value of the counter m = 0; When the wind turbine starts to rotate, each time the ultrasonic sensor detects an obstacle ahead, the value m of the counter is incremented by 1 and the distance L of the obstacle at this time is recorded. m , and finally an array L measure = [L1, L2, …, L M ; Obtain the number N of blades in the wind turbine; Obtain the array L formed by the clearance distances of the i-th blade collected in chronological order within the period T measure-i :

3. A method for early warning of safety risks of blade tower sweeping in large megawatt wind turbines according to claim 1, characterized in that, The method for obtaining the average offset of the clearance distance of each blade in the wind turbine within the period T is: Obtain the clearance distance of each blade in the wind wheel in a stationary state Average offset of clearance distance of blade No. i in the wind wheel is Among them, is the clearance distance of the i-th blade in the stationary state, L measure-i is an array formed by the clearance distances of the i-th blade collected in chronological order within the period T, and the total number of elements in the array is N i , is L measure-i the k-th element in 4. A method for early warning of the safety risk of a large MW wind turbine blade hitting the tower according to claim 3, characterized in that, The method for obtaining the minimum clearance distance of each blade is as follows:

5. A method for warning of safety risks of blade tower sweeping in a large-megawatt wind turbine according to claim 1, characterized in that, The method for obtaining the deformation degree of the blade with the largest vibration is: Obtain the moment t1 corresponding to the maximum vibration amplitude of the wind turbine within the period T; Obtain the N moments closest to the moment t1 and the corresponding collected clearance distances among the clearance distance collection moments. These clearance distances form an array A, and N is the total number of blades of the wind turbine; Obtain the maximum deformation degree d of the vibrating blade AM : d AM = max(A) - min(A).

6. The safety risk warning method for blade tower sweeping of large megawatt wind turbines according to claim 5, characterized in that, The method for obtaining the deformation degree of the blade with the largest acceleration is: Obtain the moment t2 corresponding to the maximum acceleration of the wind turbine within the period T; Obtain the N moments closest to the moment t2 and the corresponding collected clearance distances among the clearance distance collection moments. These clearance distances form an array B, and N is the total number of blades of the wind turbine; Obtain the deformation degree d of the blade with the largest vibration AC : d AC = max(B) - min(B).

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