A method for early warning of abnormal vortex vibration of a power transmission tower component

Abstract

The application discloses a kind of power transmission tower component abnormal vortex vibration early warning method, including obtaining power transmission tower component vibration image, calculating curve peak point, the center point of two peak points is selected as virtual measuring point;According to the relative displacement of the position where virtual measuring point is located by the longitudinal coordinate variation calculation of virtual measuring point;When relative displacement reaches variation threshold, determine that power transmission tower component appears vortex vibration, obtain time domain vortex vibration identification index;With relative displacement as time domain response, carry out frequency domain analysis, when energy amplitude is greater than threshold value, and duration is greater than time length threshold value, determine that power transmission tower component appears vortex vibration, obtain frequency domain vortex vibration identification index;According to time domain vortex vibration identification index and frequency domain vortex vibration identification index, determine the early warning level of power transmission tower component abnormal vortex vibration.No need to power off or climb operation, can be directly measured on the ground, greatly reduce field operation difficulty and safety risk, reduce the operation and maintenance cost, more easily in the patrol personnel and be applied.

Description

Technical Field

[0001] This invention relates to an early warning method for abnormal vortex-induced vibration of transmission tower components, belonging to the field of power infrastructure and intelligent operation and maintenance. Background Technology

[0002] Ultra-high voltage (UHV) steel pipe towers, as vital lifeline engineering projects in power infrastructure, are typically characterized by their height, large spans, and high elasticity, making them typical tall, wind-sensitive structures. In particular, critical flexible components are highly susceptible to vortex-induced vibration (vortex-induced vibration). Initially, vortex-induced vibration has small amplitudes and is difficult to detect, but long-term accumulation can lead to fatigue fracture (e.g., in 2019, a 500kV line steel pipe tower collapsed due to vortex-induced vibration causing flange bolt breakage). Real-time monitoring can provide early warnings, preventing major accidents such as tower collapse and line breakage. Traditional contact sensors (such as accelerometers and strain gauges) need to be directly pasted or fixed to the surface of the tower, which may alter the local stiffness of the component (especially for flexible structures such as thin-walled circular tubes), and may even introduce additional stress concentration due to installation damage, thus affecting the natural characteristics of vortex-induced vibration. Visual measurement, on the other hand, acquires images / videos remotely via cameras, without any contact with the measured tower, avoiding the risk of inaccurate measurements and ensuring that the measurement results reflect the true vortex-induced vibration response (such as amplitude and frequency). This is particularly important for already operational transmission towers—measurements can be taken directly from the ground without power outages or climbing, greatly reducing on-site operational difficulty and safety risks. Furthermore, using common consumer-grade devices such as cameras and smartphones for measurement significantly reduces maintenance costs and makes it easier to promote and apply among inspection personnel. The core advantages of visual measurement algorithms for identifying eddy vibrations lie in their non-contact, multi-dimensional, wide field of view, low cost, and strong anti-interference capabilities. This perfectly meets the special needs of transmission towers in high-altitude, outdoor, and strong electromagnetic environments. It avoids the installation limitations of traditional sensors while providing richer vibration information, making it a highly promising technological approach in the current field of eddy vibration monitoring, especially suitable for routine inspections by transmission line inspectors. In addition, by integrating relevant algorithms, long-term monitoring can also be performed using fixed cameras. Summary of the Invention

[0003] This invention provides an early warning method for abnormal vortex-induced vibration of transmission tower components, solving the problems disclosed in the background art.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A method for early warning of abnormal vortex-induced vibration in transmission tower components:

[0006] Acquire vibration images of transmission tower components and convert them into grayscale images;

[0007] Determine the region to be analyzed on the grayscale image, select a column of grayscale distribution curves within the region to be analyzed, calculate the peak points of the curves, and select the center point of two peak points as virtual measurement points.

[0008] Calculate the change in the ordinate of the virtual measuring point, and calculate the relative displacement of the virtual measuring point on the transmission tower component based on the change in the ordinate of the virtual measuring point;

[0009] When the relative displacement reaches the change threshold, it is determined that the transmission tower component has eddy vibration, and the time-domain eddy vibration identification index is obtained.

[0010] Frequency domain analysis is performed using relative displacement as the time domain response. When the energy amplitude is greater than the threshold and the duration is greater than the duration threshold, it is determined that the transmission tower component has vortex-induced vibration, and the frequency domain vortex-induced vibration identification index is obtained.

[0011] The warning level of abnormal vortex-induced vibration in transmission tower components is determined based on time-domain and frequency-domain vortex-induced vibration identification indicators.

[0012] Furthermore, methods for determining the region to be analyzed on a grayscale image include:

[0013] The tower components in the grayscale image are rotated according to the tilt angle so that the transmission tower components in the image remain horizontal;

[0014] The analysis region is defined as twice the width of the transmission tower component. This region must encompass both ends along its length and, perpendicular to the component, the tilt angle of the transmission tower component is... Then rotate the image. The angle ensures that the transmission tower components in the image remain horizontal.

[0015] Furthermore, based on the grayscale distribution curve of a certain column of values ​​within the region to be analyzed, a fast peak-finding method is used to determine the center point of the two highest peak points as virtual measurement points. These virtual measurement points must satisfy the following conditions:

[0016] ;

[0017] ;

[0018] In the formula, and These are the vertical coordinates of the region to be analyzed. and This represents the vertical coordinate value of the peak point in the grayscale distribution curve.

[0019] Furthermore, the formula for calculating the change in the ordinate of the virtual measuring point is:

[0020] ;

[0021] In the formula, Dis represents the displacement calculation result of the virtual measuring point. Let j be the vertical coordinate of the j-th virtual measurement point image. The vertical coordinates of the first virtual measurement point image.

[0022] Furthermore, the formula for calculating the relative displacement of the virtual measuring point on the transmission tower component based on the change in the ordinate of the virtual measuring point is as follows:

[0023] ;

[0024] in, The results are for relative displacement calculations; The image length of the transmission tower member is expressed in pixels.

[0025] Furthermore, when the relative displacement of the transmission tower component image reaches 3‰, it is determined that the transmission tower component has vortex-induced vibration; 3‰, 5‰, and 1% are respectively used as the three-level time-domain early warning thresholds.

[0026] Furthermore, frequency domain analysis is performed using relative displacement as the time domain response. When the energy amplitude is greater than a threshold and the duration is greater than the duration threshold, vortex-induced vibration is determined to occur in the transmission tower component. The method for obtaining the frequency domain vortex-induced vibration identification index includes: performing a Fourier transform on the relative displacement calculation result as the time domain response to obtain the frequency domain result, and using peak value extraction to obtain the dominant frequency value of the time domain response for that segment. A short-time Fourier transform is performed to obtain the time-frequency change trend result, and the trend of frequency value change with time is analyzed within the range of ±1 of the dominant frequency value. If the energy concentration area continues to appear near the dominant frequency: when the energy amplitude is greater than 0.5 and the duration is greater than 30 seconds, vortex-induced vibration is determined to occur in the transmission tower component. A three-level judgment index with vortex-induced vibration duration as the early warning index is established, with 30 seconds, 1 minute, and 3 minutes as the three-level frequency domain early warning thresholds.

[0027] Furthermore, methods for determining the early warning level of abnormal eddy vibration in transmission tower components based on time-domain and frequency-domain eddy vibration identification indices include:

[0028] If the relative displacement is less than 3‰; and / or the duration of the energy amplitude greater than 0.5 is less than 30 seconds; the warning level is determined to be Level 5.

[0029] If the relative displacement is greater than 3‰ and less than 5‰; and / or the duration of the energy amplitude is greater than 0.5 and less than 30 seconds but less than 1 minute, the warning level is determined to be Level IV.

[0030] If the relative displacement is greater than 5‰ and less than 1%, and / or the duration of the energy amplitude being greater than 0.5 is more than 1 minute but less than 3 minutes, the warning level is determined to be Level III.

[0031] If the relative displacement is greater than 3‰ and less than 5‰, or if the duration of the energy amplitude is greater than 0.5 for more than 3 minutes, the warning level is determined to be Level II.

[0032] If the relative displacement is greater than 3‰ and less than 5‰, or if the duration of the energy amplitude is greater than 0.5 for more than 3 minutes, the warning level is determined to be Level 1.

[0033] The beneficial effects achieved by this invention are as follows:

[0034] 1. This invention uses a visual measurement method based on devices such as cameras or smartphones to obtain the vibration response of transmission tower components. Compared with existing accelerometers, this method has a faster measurement speed, lower measurement cost, and better visualization effect. Compared with manual observation methods, this method has higher accuracy and can make quantitative judgments.

[0035] 2. This invention obtains the vibration process of transmission tower components through a portable visual device, without the need for additional line laying or power supply operations. It can quickly identify sudden situations such as vortex-induced vibration and provide power line inspection personnel with an effective means of operation and maintenance assessment.

[0036] 3. This invention proposes a method for setting up virtual measuring points based on dual peaks. By utilizing the common gray-scale distribution characteristics of the edges of slender rods, it is possible to stably and accurately extract the vibration response of key locations of transmission tower components without the need to set up targets, thus enhancing the practicality, adaptability and operability of the technology.

[0037] 4. This invention establishes a vortex vibration measurement method based on relative displacement. This method uses the length of the rod as a reference benchmark, which solves the calibration problem of long-distance measurement in real-world scenarios. It can meet the needs of rapid measurement and evaluation of vibration response of rods of different lengths and measurement distances and angles, further improving its usability in actual engineering and its understandability for ordinary line patrol personnel.

[0038] 5. This invention constructs an eddy vibration identification index for transmission tower components based on time-domain response and frequency-domain response, realizing the identification and judgment of abnormal eddy vibration of transmission tower components in real-world scenarios from two different dimensions, thereby improving the accuracy of abnormal eddy vibration identification.

[0039] 6. Based on the constructed time-frequency index, this invention further establishes a hierarchical judgment and control system for abnormal vortex-induced vibration of transmission tower components, and provides judgment criteria and control measures for abnormal vortex-induced vibration of transmission tower components under different conditions, which helps to promote the intelligent development of power grid operation and maintenance. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the process of the present invention;

[0041] Figure 2 This is a schematic diagram of on-site data acquisition by the vision device for power transmission tower components in this invention;

[0042] Figure 3 This is a schematic diagram of the measurement images of the transmission towers acquired in this invention;

[0043] Figure 4 This is a schematic diagram illustrating the determination of the analysis region in this invention;

[0044] Figure 5 This is a schematic diagram illustrating the determination of grayscale distribution and virtual measuring point positions in this invention.

[0045] Figure 6 This is a schematic diagram of the time-domain results of eddy vibration of transmission tower components in this invention;

[0046] Figure 7 This is a schematic diagram of the vortex-induced vibration frequency domain results of the transmission tower components in this invention. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0048] like Figure 1 As shown, this invention discloses an early warning method for abnormal vortex-induced vibration of transmission tower components, comprising the following steps:

[0049] Step 1: Use a camera or smartphone to capture vibration images of the transmission tower components. It is essential to ensure that the complete dimensions of the transmission tower component being measured are within the field of view. The on-site experimental setup is as follows: Figure 2 As shown, the collected images are uploaded to the cloud platform and a specified program is called for processing;

[0050] Step two: Convert the color image captured by the camera into a grayscale image, that is, convert the RGB three-channel image into a single-channel image.

[0051] Step 3: Determine the tilt angle of the transmission tower components and rotate the tower components in the measurement image according to the tilt angle, so that the transmission tower components under test in the acquired image remain horizontal, such as... Figure 3 As shown;

[0052] Step four: Determine the area to be analyzed as twice the width of the transmission tower component. The analysis area must cover both ends along its length. In the direction perpendicular to the component, the tilt angle of the transmission tower component is... Further rotate the image Angle, so that the transmission tower components under test remain horizontal in the acquired image, such as Figure 4 As shown;

[0053] Step 5: Select a column of values ​​within the area to be analyzed and analyze its grayscale distribution curve, such as... Figure 5 As shown, based on a given grayscale distribution curve, a fast peak-finding method is used to obtain the two largest peak points of the curve:

[0054] Step six: There are exactly two peaks, one greater than the grayscale value and the other less than the grayscale value, and both peaks are located within the analysis area of ​​the transmission tower component, i.e.:

[0055]

[0056]

[0057] In the formula, and These are the vertical coordinates of the region to be analyzed. and This represents the vertical coordinate value of the peak point in the grayscale distribution curve.

[0058] Step 7: After determining the peak points, further determine the locations of the virtual measuring points. To ensure the stability of the measuring points, based on the above regional constraints, further select the center point of the two peak locations as the virtual measuring points, that is:

[0059]

[0060] In the formula, The vertical coordinate of the measuring point is given. Since the tower components have been rotated to the horizontal direction, the vibration response can be obtained by changing the vertical coordinate, and the horizontal coordinate does not need to be considered.

[0061] Step 8: Further calculate the change in the ordinate of the virtual measurement points in the image sequence. The calculation process is as follows:

[0062]

[0063] Where Dis represents the image displacement calculation result. Let j be the vertical coordinate of the j-th measurement image. The vertical coordinates of the first measurement image (reference image).

[0064] Step 9: Based on the changes in the ordinate obtained in the above steps, the image displacement-measurement time curves of key positions of the transmission tower members can be obtained, and the time-domain vibration response of the transmission tower can be further plotted.

[0065] Step 10: Considering the difficulty of displacement calibration in actual engineering projects, the often high height of transmission towers makes it difficult to install calibration plates, and distance-based calibration methods are difficult for on-site patrol personnel to accurately and quickly grasp. Therefore, a relative displacement evaluation index that does not require calibration was further established to facilitate rapid evaluation of the vibration of transmission tower components, i.e., relative displacement. The calculation process is as follows:

[0066]

[0067] In the formula, The results are for relative displacement calculation. The image length (in pixels) of the transmission tower members is defined. This index can meet the needs of rapid assessment of vibration response of members with different measurement distances and angles, as well as different lengths, further improving its usability in actual engineering and its understandability for ordinary line patrol personnel.

[0068] Specifically, in this experiment, the length of the rod image was 1317 pixels, and the image displacement of the vortex-induced vibration was approximately 3-10 pixels. Further, based on the relative displacement time history curve obtained from the above formula, the time-domain response results are as follows: Figure 6 As shown.

[0069] Step 11: When the relative displacement of the rod image reaches 3‰, it can be determined that vortex-induced vibration has occurred. Further establish a three-level early warning index, with 3‰, 5‰ and 1% as the three-level early warning thresholds respectively.

[0070] Step 12: Perform a Fourier transform on the time-domain response to obtain the frequency-domain result, and use peak extraction to obtain the dominant frequency value of the time-domain response for this segment. Further perform a short-time Fourier transform to obtain the time-frequency variation trend result, such as... Figure 7 As shown, the trend of frequency value change with time within the range of ±1 of the dominant frequency value is analyzed. If the energy concentration area continues to appear near the dominant frequency, when the energy amplitude (after normalization) is greater than 0.5 and the duration is greater than 30 seconds, it is determined that vortex oscillation has occurred. A three-level judgment index with vortex oscillation duration as the early warning index is established, with 30 seconds, 1 minute, and 3 minutes as the three-level early warning thresholds.

[0071] Step 13: Based on the time domain and frequency domain results, it can be seen that the eddy vibration amplitude in the time domain exceeds 5‰, and the duration of the dominant frequency in the frequency domain exceeds 1 minute. According to the abnormal eddy vibration warning classification and control system for transmission tower components in Table 1, it can be determined that the current level is the second level.

[0072] Table 1. Early warning and control system for abnormal vortex-induced vibration of transmission tower components;

[0073]

[0074] Step Fourteen: After completing the above judgment on vortex-induced vibration, the key judgment indicators and control measures will be automatically pushed to the patrol personnel or the head of the inspection team via WeChat or SMS to facilitate quick judgment and handling by on-site personnel. According to the requirements of the control and early warning system, on-site inspection personnel need to report vortex-induced vibration information and do a good job in information statistics.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0076] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0077] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0078] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0080] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for early warning of abnormal vortex-induced vibration in transmission tower components, characterized in that: Acquire vibration images of transmission tower components and convert them into grayscale images; Determine the region to be analyzed on the grayscale image, select a column of grayscale distribution curves within the region to be analyzed, calculate the peak points of the curves, and select the center point of two peak points as virtual measurement points. Calculate the change in the ordinate of the virtual measuring point, and calculate the relative displacement of the virtual measuring point on the transmission tower component based on the change in the ordinate of the virtual measuring point; When the relative displacement reaches the change threshold, it is determined that the transmission tower component has eddy vibration, and the time-domain eddy vibration identification index is obtained. Frequency domain analysis is performed using relative displacement as the time domain response. When the energy amplitude is greater than the threshold and the duration is greater than the duration threshold, it is determined that the transmission tower component has vortex-induced vibration, and the frequency domain vortex-induced vibration identification index is obtained. The warning level of abnormal vortex-induced vibration in transmission tower components is determined based on time-domain and frequency-domain vortex-induced vibration identification indicators.

2. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 1, characterized in that, Methods for determining the region to be analyzed on a grayscale image include: The tower components in the grayscale image are rotated according to the tilt angle so that the transmission tower components in the image remain horizontal; The analysis region is defined as twice the width of the transmission tower component. This region must encompass both ends along its length and, perpendicular to the component, the tilt angle of the transmission tower component is... Then rotate the image. The angle ensures that the transmission tower components in the image remain horizontal.

3. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 1, characterized in that, The method for selecting the grayscale distribution curve of a specific column of values ​​within the region to be analyzed is as follows: ； ； In the formula, and These are the vertical coordinates of the region to be analyzed. and This represents the vertical coordinate value of the peak point in the grayscale distribution curve.

4. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 3, characterized in that, The formula for calculating the peak point of the curve is: ； in, This represents the degree of grayscale deviation of the i-th point in this column. Let be the gray value of the i-th point. This is the average grayscale value of all points in this column. This is the standard deviation of the gray values ​​of all points in this column.

5. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 4, characterized in that, The formula for selecting the center point of two peak points as the virtual measuring point is: ； In the formula, The vertical coordinate of the virtual measuring point is used. The grayscale image of the tower component is rotated to the horizontal direction, and the vibration response is obtained by changing the vertical coordinate.

6. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 5, characterized in that, The formula for calculating the change in the ordinate of a virtual measuring point is: ； Where Dis represents the displacement calculation result of the virtual measuring point. Let j be the vertical coordinate of the j-th virtual measurement point image. The vertical coordinates of the first virtual measurement point image.

7. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 6, characterized in that, The formula for calculating the relative displacement of the virtual measuring point on the transmission tower component based on the change in the ordinate of the virtual measuring point is as follows: ； in, The results are for relative displacement calculations; The image length of the transmission tower member is expressed in pixels.

8. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 7, characterized in that, When the relative displacement of the transmission tower component image reaches 3‰, it is determined that the transmission tower component has vortex-induced vibration; 3‰, 5‰, and 1% are respectively used as the three-level time domain early warning thresholds.

9. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 8, characterized in that, Using relative displacement as the time-domain response for frequency-domain analysis, when the energy amplitude is greater than a threshold and the duration is greater than the duration threshold, vortex-induced vibration is determined to occur in the transmission tower component. The method for obtaining the frequency-domain vortex-induced vibration identification index includes: performing a Fourier transform on the relative displacement calculation result as the time-domain response to obtain the frequency-domain result, and using peak value extraction to obtain the dominant frequency value of the time-domain response for that segment, performing a short-time Fourier transform to obtain the time-frequency change trend result, and analyzing the trend of frequency value change with time within the range of ±1 of the dominant frequency value. If the energy concentration area continues to appear near the dominant frequency: when the energy amplitude is greater than 0.5 and the duration is greater than 30 seconds, vortex-induced vibration is determined to occur in the transmission tower component, and a three-level judgment index with vortex-induced vibration duration as the early warning index is established, with 30 seconds, 1 minute, and 3 minutes as the three-level frequency-domain early warning thresholds.

10. The early warning method for abnormal vortex-induced vibration of transmission tower components according to claim 9, characterized in that, Methods for determining the early warning level of abnormal eddy vibration in transmission tower components based on time-domain and frequency-domain eddy vibration identification indices include: If the relative displacement is less than 3‰; and / or the duration of the energy amplitude greater than 0.5 is less than 30 seconds; the warning level is determined to be Level 5. If the relative displacement is greater than 3‰ and less than 5‰; and / or the duration of the energy amplitude is greater than 0.5 and less than 30 seconds but less than 1 minute, the warning level is determined to be Level IV. If the relative displacement is greater than 5‰ and less than 1%, and / or the duration of the energy amplitude being greater than 0.5 is more than 1 minute but less than 3 minutes, the warning level is determined to be Level III. If the relative displacement is greater than 3‰ and less than 5‰, or if the duration of the energy amplitude is greater than 0.5 for more than 3 minutes, the warning level is determined to be Level II. If the relative displacement is greater than 3‰ and less than 5‰, or if the duration of the energy amplitude is greater than 0.5 for more than 3 minutes, the warning level is determined to be Level 1.

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