Method and system for judging automatic suspension of high-voltage grounding wire of transformer substation or converter station

Abstract

The invention discloses an automatic suspension judgment method and system for a high-voltage grounding wire of a transformer substation or a converter station. The method comprises the following steps: S1, acquiring a video image of a grounding wire clamping opening in real time; s2, carrying out subtraction operation on two continuous frames of images to generate a difference image, and counting the number of pixel points exceeding a preset threshold value; if the number of the pixel points exceeding the threshold value reaches a preset proportion or total number, judging that the hanging position of the grounding wire is correct; s3, continuously collecting video images of the ground wire clamping opening; s4, cutting the video image acquired in the step S3, intercepting a target region of interest, and converting a color image into a grayscale image; s5, performing linear point operation and gray stretching processing on the gray image; and S6, carrying out threshold segmentation on the grayscale image to generate a binary image, and judging whether the grounding wire clamping opening is attached to the wire or not by calculating the black and white pixel proportion of the target area and comparing the black and white pixel proportion with a preset proportion threshold. The device has the advantages of high automation level, accurate grounding detection and the like.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of electric power equipment, and in particular to a method and system for automatically judging the suspension of a high-voltage grounding wire in a transformer substation or a converter station. Background Art

[0002] In the power system, substations or converter stations serve as power transfer stations, connecting the upper power grid with the lower loads. The safety, reliability, and stability of their operation directly affect the reliable operation of the power system. Therefore, regular inspection and maintenance of various equipment in substations / converter stations is one of the necessary means to prevent power outages and ensure that substations / converter stations continue to output high-quality power.

[0003] Hanging and connecting the ground wire is a crucial part of the maintenance work. It is a necessary measure to ensure the personal safety of the workers during the maintenance work. The ground wire supervisor and the ground wire operator are specifically responsible for the hanging and removing of the ground wire. This operation is labor-intensive, and the frequency of hanging and removing the ground wire is high. It also takes up a long time for maintenance. According to relevant regulations, working on electrical equipment requires power outage, electrical testing, grounding, hanging signs and installing barriers. Grounding is achieved by installing ground wires on the conductors on both sides of the power-off equipment. Its purpose is to prevent sudden power outages on the lines or equipment during work and protect the personal safety of maintenance workers.

[0004] Currently, most substations and converter stations still rely on traditional manual hand-held installation and removal for grounding wires, which requires high levels of physical fitness and technical proficiency from maintenance workers and is time-consuming. A few substations and converter stations use aerial ladders to lift maintenance workers to install and remove grounding wires for higher-voltage lines and facilities, but this still relies on manual installation. While this reduces physical exertion for maintenance workers, it also significantly shortens their safety distance and increases the risk of falls from height during height-related operations. Furthermore, the use of aerial work platforms for installing grounding wires increases production costs. Furthermore, installing grounding wires presents a range of safety hazards and potential accidents, such as installing grounding wires without conducting electrical tests, reliability issues with the installation, and the potential for missed or incorrect installations.

[0005] Initial research has been conducted on automatic hooking and removal devices for high-voltage grounding wires. Jia Fengming and others have developed a method for hooking and removing grounding wires from high altitudes, simplifying these operations. Ning Boyang and others have developed an electric-assisted operating device that can provide directional guidance for rapid hooking and removal of grounding wires, enabling quick and effortless hooking and removal. Ning Boyang and others have also developed an electric-assisted operating device that can provide directional guidance for rapid hooking and removal of grounding wires, powered by a transmission device. However, limited research has focused on the accuracy of hooking and removing grounding wires, preventing maintenance personnel from quickly and reliably determining whether high-voltage grounding wires are properly hooked. Summary of the Invention

[0006] In response to the technical problems existing in the prior art, the present invention provides a method and system for automatically judging the suspension of high-voltage grounding wires in a substation or converter station with a high level of automation and precise grounding detection.

[0007] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0008] A method for automatically determining whether a high-voltage grounding wire in a transformer substation or a converter station is automatically suspended comprises the following steps:

[0009] S1. When the ground wire automatic suspension device brings the ground wire close to the maintenance line, real-time video images of the ground wire clamp are captured;

[0010] S2. Subtract two consecutive frames of the video image using an inter-frame difference method to generate a differential image. Then, through binarization, the number of pixels exceeding a preset threshold is counted. If the number of pixels exceeding the threshold reaches a preset ratio or total number, the ground wire is determined to be in the correct hanging position, and step S3 is triggered.

[0011] S3. After the grounding wire is correctly positioned, the automatic grounding wire suspension device continues to approach the maintenance line until the line to be repaired is completely inserted into the grounding wire clamp, and continuously captures video images of the grounding wire clamp;

[0012] S4. Crop the video image collected in step S3 to capture the target region of interest and convert the color image into a grayscale image using a grayscale conversion algorithm;

[0013] S5. Performing linear point operation and grayscale stretching on the grayscale image to enhance image contrast;

[0014] S6. Perform threshold segmentation on the grayscale image processed in step S5 to generate a binary image. By calculating the ratio of black and white pixels in the target area and comparing it with the preset ratio threshold, determine whether the grounding wire clamp fits the wire and complete the suspension result determination.

[0015] Preferably, in step S4, the specific method of converting the color image into a grayscale image by using the grayscale conversion algorithm is:

[0016] Gray(x,y)=0.299*R(x,y)+0.587*G(x,y)+0.114*B(x,y)

[0017] In the formula, Gray(x,y) is the grayscale value of the pixel at x and y in the image, and R, G, and B are the values ​​of the three color components at the pixel. After Gray(x,y) is calculated by the above formula, R, G, and B in the image are replaced by Gray to obtain the grayscale image of the original image.

[0018] Preferably, in step S5, the linear point operation refers to an operation in which the input grayscale and the output grayscale are in a linear relationship, and the grayscale transformation formula is as follows:

[0019] g(x,y)=P*f(x,y)+L

[0020] Where f(x,y) is the grayscale value of the input image at point (x,y), g(x,y) is the grayscale value of the output image at the corresponding point, P is the slope of the grayscale linear transformation, and L is the transformation coefficient.

[0021] Preferably, in step S5, grayscale stretching is one of the image point operation processing methods, which expands the grayscale range of the input image to the entire grayscale level, making the image easier to distinguish. The grayscale transformation formula is as follows:

[0022]

[0023] Among them, A and B are the minimum and maximum grayscale values ​​of the input image respectively. The purpose of grayscale stretching is to linearly map the grayscale values ​​from A to B to 0 to 255. The grayscale value differences in different areas of the processed image are more obvious, thereby improving the visual effect of the image.

[0024] Preferably, in step S6, threshold segmentation refers to dividing the input image into two parts by a set feature threshold N, and the calculation formula is:

[0025]

[0026] Where b0 and b1 divide the image into two parts. If b0 = 0, it represents black, and b1 = 1, it represents white, that is, the image is binarized.

[0027] Preferably, in step S6, the threshold N is selected by an iterative method, specifically:

[0028] S61. Select the median of the grayscale value [0, M] of the input image as the initial threshold N0, and count the number of pixels C corresponding to each grayscale level i in the image. i ; Where M is the maximum grayscale value of the input image;

[0029] S62. Use the initial threshold N0 to segment the image into two parts: R1 and R2, and calculate their average grayscale μ1 and μ2 respectively. The calculation formula is as follows:

[0030]

[0031] Where i represents the gray level, N i represents the new threshold after iteration, C i Indicates the number of pixels corresponding to gray level i;

[0032] S63. Recalculate the new threshold N1 using μ1 and μ2 in the above formula:

[0033]

[0034] S64. Use the new threshold to split the image into two parts and calculate the average grayscale to get a new threshold. Repeat this step until N i+1 and N i Until the difference is less than the preset given value d.

[0035] Preferably, in step S6, the ground wire hanging criterion result is judged for the binarized image. The judgment method is: by analyzing and calculating the black and white pixel ratio of a specified area in the ground wire clamp image, whether the clamp is hung in place is judged. The pixel ratio calculation formula is as follows:

[0036]

[0037] Among them, the number of black pixels is Z0 and the ratio is R1, the number of white pixels is Z1 and the ratio is R2. If the ratio is greater than the specified threshold, the grounding wire hanging result is determined: when the grounding wire clamp is in the fitted state, the black pixel ratio of the selected target area is relatively large.

[0038] The present invention also discloses a computer program product, comprising a computer program, which executes the steps of the above method when executed by a processor.

[0039] The present invention further discloses a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the method described above are executed.

[0040] The present invention also discloses a criterion system for automatically suspending high-voltage grounding wires in a transformer substation or converter station, comprising a memory and a processor connected to each other, wherein a computer program is stored on the memory, and when the computer program is run by the processor, the steps of the above method are executed.

[0041] Compared with the prior art, the advantages of the present invention are:

[0042] The present invention captures video images of the grounding wire clamp during operation, first detecting the grounding rod's hanging position. Once the position is correct, the hanging device brings the grounding rod clamp close to the conductor. Digital image processing technology is used to determine whether the clamp is in contact with the conductor, and the automatic hanging device finally completes the grounding wire hanging operation. This invention helps improve the automation level of substations or converter stations and provides a solid foundation for unmanned substation / converter station operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of an embodiment of the method for automatically judging whether a high-voltage grounding wire is suspended according to the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1 As shown, the embodiment of the present invention provides a method for determining the automatic suspension of a high-voltage grounding wire in a substation or converter station, comprising the following steps:

[0046] S1. When the ground wire automatic suspension device brings the ground wire close to the maintenance line, real-time video images of the ground wire clamp are captured;

[0047] S2. Subtract two consecutive frames of the video image using an inter-frame difference method to generate a differential image. Binarize the image and count the number of pixels exceeding a preset threshold. If the number of pixels exceeding the threshold reaches a preset ratio or total number, the ground wire is determined to be correctly positioned, triggering step S3.

[0048] S3. After the grounding wire is correctly positioned, the automatic grounding wire suspension device continues to approach the maintenance line until the line to be repaired is completely inserted into the grounding wire clamp, and continuously captures video images of the grounding wire clamp;

[0049] S4. Crop the video image collected in step S3 to capture the target region of interest and convert the color image into a grayscale image using a grayscale conversion algorithm;

[0050] S5. Performing linear point operation and grayscale stretching on the grayscale image to enhance image contrast;

[0051] S6. Perform threshold segmentation on the grayscale image processed in step S5 to generate a binary image. By calculating the ratio of black and white pixels in the target area and comparing it with the preset ratio threshold, determine whether the grounding wire clamp fits the wire and complete the suspension result determination.

[0052] In step S1, the automatic hanging device for the grounding wire is equipped with an automatic monitoring device. When the automatic hanging device starts to work, the grounding wire clamp is automatically recorded and stored to obtain a video image of the grounding wire clamp.

[0053] In step S2, a subtraction operation is performed on two consecutive frames of the grounding wire clamp video image to obtain a difference image, and the number of pixels exceeding a preset threshold is counted. If the number of pixels exceeding the threshold reaches a preset ratio (e.g., 75%-90%) or the total number, the grounding wire hanging position is determined to be correct, and step S3 is triggered.

[0054] In step S3, the automatic grounding wire hanging device receives a signal indicating that the hanging position is correct, and continues to move the grounding wire closer to the maintenance line until the line to be maintained completely enters the grounding wire clamp.

[0055] In step S4, the original image is cropped to capture the target region of interest. Since the relative position of the camera and the ground wire remains fixed during automatic suspension, the selected region remains unchanged for each crop. This cropping process allows portions of the image that are not relevant to the object being detected to be ignored, minimizing the impact on the detection results and reducing the processing time for subsequent steps.

[0056] To speed up image processing, image processing algorithms often require converting color images into grayscale images. A grayscale image divides white to black into 256 grayscale levels. Each pixel in the image contains only brightness information, ignoring color information. There are three ways to convert a color image to a grayscale image. The conversion formulas are as follows:

[0057] Gray(x,y)=[R(x,y)+G(x,y)+B(x,y)] / 3

[0058] Gray(x,y)=0.299*R(x,y)+0.587*G(x,y)+0.114*B(x,y)

[0059] Gray(x,y)=G(x,y)

[0060] In the three formulas above, Gray(x,y) represents the grayscale value of the pixel at x and y in the image, and R, G, and B represent the values ​​of the three color components at that pixel. After calculating Gray(x,y) using the above formulas, replace R, G, and B in the image with Gray to obtain the grayscale image of the original image. Since the human eye is more sensitive to green of the three colors, increasing the proportion of green in the conversion process can achieve better image processing results. In practical applications, the second grayscale conversion method is generally used.

[0061] In step S5, the linear point operation refers to an operation in which the input grayscale and the output grayscale are in a linear relationship. The grayscale transformation formula is as follows:

[0062] g(x,y)=P*f(x,y)+L

[0063] Among them, f(x,y) is the grayscale value of the input image at the point (x,y), g(x,y) is the grayscale value of the output image at the corresponding point, P is the slope of the grayscale linear transformation; L is the transformation coefficient; when P=1, L=0, the input and output are equal, that is, the original image is output; when P=1, L>0, the output grayscale value becomes larger and the overall image becomes brighter; when P>1, the contrast of the output image increases; when P<0, the dark area of ​​the image becomes brighter and the bright area becomes darker, that is, the image contrast decreases.

[0064] Grayscale stretching is a method of image point operation processing. It expands the grayscale range of the input image to the entire grayscale level, making the image easier to distinguish. The grayscale transformation formula is as follows:

[0065]

[0066] Among them, A and B are the minimum and maximum grayscale values ​​of the input image respectively. The purpose of grayscale stretching is to linearly map the grayscale values ​​from A to B to 0 to 255. The grayscale value differences in different areas of the processed image are more obvious, thereby improving the visual effect of the image.

[0067] In step S6, the image is subjected to threshold segmentation processing. Threshold segmentation refers to dividing the input image into two parts by a set feature threshold N. The calculation formula is:

[0068]

[0069] In the formula, b0 and b1 divide the image into two parts. If b0 = 0 represents black and b1 = 1 represents white, the image is binarized. Threshold segmentation is one of the most commonly used image segmentation methods and is suitable for situations where the grayscale levels of the target and background differ greatly. There are many ways to select the threshold N: iterative method, maximum inter-class variance method, one-dimensional maximum entropy method, two-dimensional maximum entropy method, and simple statistical method. Among them, the basic idea of ​​the iterative method is: first select an initial threshold, and then continuously change this threshold through calculation until the specified conditions are met. The specific steps are as follows:

[0070] S61. Select the median of the grayscale value [0, M] of the input image as the initial threshold N0, and count the number of pixels C corresponding to each grayscale level i in the image. i ; Where M is the maximum grayscale value of the input image;

[0071] S62. Use the initial threshold N0 to segment the image into two parts: R1 and R2, and calculate their average grayscale μ1 and μ2 respectively. The calculation formula is as follows:

[0072]

[0073] Where i represents the gray level, N i represents the new threshold after iteration, C i Indicates the number of pixels corresponding to gray level i;

[0074] S63. Recalculate the new threshold N1 using μ1 and μ2 in the above formula:

[0075]

[0076] S64. Use the new threshold to split the image into two parts and calculate the average grayscale (specific method is step S62) to obtain a new threshold (specific method is step S63), and repeat this step until N i+1 and N i Until the difference is less than the preset given value d.

[0077] By comparing the threshold, the part of the image with a larger difference in grayscale is removed, while the part with a smaller difference is retained. The image obtained after threshold segmentation is a binary image.

[0078] For the binarized image, the grounding wire hanging criterion result is judged. The judgment method is to analyze and calculate the black and white pixel ratio of the specified area in the grounding wire clamp image to determine whether the clamp is hung in place. The pixel ratio calculation formula is as follows:

[0079]

[0080] Among them, the number of black pixels is Z0 and the ratio is R1, the number of white pixels is Z1 and the ratio is R2. If the ratio is greater than the specified threshold (such as 70%-85%), the grounding wire hanging result can be determined: when the grounding wire clamp is in a fitted state, the proportion of black pixels in the selected target area is relatively large.

[0081] The present invention captures video images of the grounding wire clamp during operation, first detecting the grounding rod's hanging position. Once the position is correct, the hanging device brings the grounding rod clamp close to the conductor. Digital image processing technology is used to determine whether the clamp is in contact with the conductor, and the automatic hanging device finally completes the grounding wire hanging operation. This invention helps improve the automation level of substations and converter stations and provides a solid foundation for unmanned substation and converter station operations.

[0082] An embodiment of the present invention further discloses a computer program product, including a computer program, which executes the steps of the above-mentioned method when executed by a processor. An embodiment of the present invention further discloses a computer-readable storage medium, on which a computer program is stored, which executes the steps of the above-mentioned method when executed by a processor. An embodiment of the present invention further discloses a system for automatically suspending high-voltage grounding wires in a substation / converter station, including a memory and a processor connected to each other, the memory storing a computer program, which executes the steps of the above-mentioned method when executed by the processor. The product, medium, and system of the present invention correspond to the above-mentioned method and also have the advantages described in the above-mentioned method.

[0083] The present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned method embodiment. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable storage media include: any entity or device that can carry computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. The memory is used to store computer programs and / or modules, and the processor implements various functions by running or executing computer programs and / or modules stored in the memory, and calling data stored in the memory. The memory may include high-speed random access memory and non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0084] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for automatically determining whether a high-voltage grounding wire in a substation or converter station is suspended, characterized in that: Including steps: S1. When the ground wire automatic suspension device brings the ground wire close to the maintenance line, real-time video images of the ground wire clamp are captured; S2. Subtract two consecutive frames of the video image using an inter-frame difference method to generate a differential image. Then, through binarization, the number of pixels exceeding a preset threshold is counted. If the number of pixels exceeding the threshold reaches a preset ratio or total number, the ground wire is determined to be in the correct hanging position, and step S3 is triggered. S3. After the grounding wire is correctly positioned, the automatic grounding wire suspension device continues to approach the maintenance line until the line to be repaired is completely inserted into the grounding wire clamp, and continuously captures video images of the grounding wire clamp; S4. Crop the video image collected in step S3 to capture the target region of interest and convert the color image into a grayscale image using a grayscale conversion algorithm; S5. Performing linear point operations and grayscale stretching on the grayscale image to enhance image contrast; S6. Perform threshold segmentation on the grayscale image processed in step S5 to generate a binary image. By calculating the ratio of black and white pixels in the target area and comparing it with the preset ratio threshold, determine whether the grounding wire clamp fits the wire and complete the suspension result determination.

2. The method for automatically determining whether a high-voltage grounding wire in a transformer substation or converter station is suspended according to claim 1, wherein: In step S4, the specific method of converting the color image into a grayscale image by using the grayscale conversion algorithm is as follows: Gray(x,y)=0.299*R(x,y)+0.587*G(x,y)+0.114*B(x,y) In the formula, Gray(x,y) is the grayscale value of the pixel at x and y in the image, and R, G, and B are the values ​​of the three color components at the pixel. After Gray(x,y) is calculated by the above formula, R, G, and B in the image are replaced by Gray to obtain the grayscale image of the original image.

3. The method for automatically determining whether a high-voltage grounding wire in a transformer substation or converter station is suspended according to claim 1, wherein: In step S5, the linear point operation refers to an operation in which the input grayscale and the output grayscale are linearly related. The grayscale transformation formula is as follows: g(x,y)=P*f(x,y)+L Where f(x,y) is the grayscale value of the input image at point (x,y), g(x,y) is the grayscale value of the output image at the corresponding point, P is the slope of the grayscale linear transformation, and L is the transformation coefficient.

4. The method for automatically determining whether a high-voltage grounding wire in a transformer substation or converter station is suspended according to claim 3, wherein: In step S5, grayscale stretching is one of the image point operation processing methods. It expands the grayscale range of the input image to the entire grayscale level, making the image easier to distinguish. The grayscale transformation formula is as follows: Among them, A and B are the minimum and maximum grayscale values ​​of the input image respectively. The purpose of grayscale stretching is to linearly map the grayscale values ​​from A to B to 0 to 255. The grayscale value differences in different areas of the processed image are more obvious, thereby improving the visual effect of the image.

5. The method for automatically determining whether a high-voltage grounding wire in a transformer substation or converter station is suspended according to any one of claims 1 to 4, characterized in that: In step S6, threshold segmentation refers to dividing the input image into two parts by setting the feature threshold N. The calculation formula is: Where b0 and b1 divide the image into two parts. If b0 = 0, it represents black, and b1 = 1, it represents white, that is, the image is binarized.

6. The method for automatically determining whether a high-voltage grounding wire in a transformer substation or converter station is suspended according to claim 5, characterized in that: In step S6, the threshold N is selected using an iterative method, specifically: S61. Select the median of the grayscale value [0, M] of the input image as the initial threshold N0, and count the number of pixels C corresponding to each grayscale level i in the image. i ; Where M is the maximum grayscale value of the input image; S62. Use the initial threshold N0 to segment the image into two parts: R1 and R2, and calculate their average grayscale μ1 and μ2 respectively. The calculation formula is as follows: Where i represents the gray level, N i represents the new threshold after iteration, C i Indicates the number of pixels corresponding to gray level i; S63. Recalculate the new threshold N1 using μ1 and μ2 in the above formula: S64. Use the new threshold to divide the image into two parts and calculate the average grayscale to obtain a new threshold; repeat this step until N i+1 With N i Until the difference is less than the preset given value d.

7. The method for automatically determining whether a high-voltage grounding wire in a transformer substation or converter station is suspended according to any one of claims 1 to 4, characterized in that: In step S6, the ground wire hanging criterion result is judged for the binarized image. The judgment method is: by analyzing and calculating the black and white pixel ratio of the specified area in the ground wire clamp image, whether the clamp is hung in place is judged. The pixel ratio calculation formula is as follows: Among them, the number of black pixels is Z0 and the ratio is R1; the number of white pixels is Z1 and the ratio is R2. If the ratio is greater than the specified threshold, the grounding wire hanging result is determined: when the grounding wire clamp is in the fitted state, the proportion of black pixels in the selected target area is relatively large.

8. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are performed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 7.

10. A system for automatically suspending a high-voltage grounding wire in a transformer substation or converter station, comprising a memory and a processor connected to each other, wherein a computer program is stored in the memory, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 7.

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