Method for judging ice condition of power transmission line

Abstract

The application provides a power transmission line ice condition judgment method, and belongs to the technical field of ice calculation. When the line is covered with ice, the curved shape of the line is fitted and determined. According to the curved condition of the line, the weight of the ice is inferred through the change of stress and strain on the line and related historical data. The volume of the ice in a certain range is determined through a monitoring instrument, and the density of the ice is determined according to the determined volume and the weight of the ice in the corresponding region. The power transmission line ice condition judgment method provided by the application can effectively infer the actual condition of the ice through analysis and calculation, so that more accurate data support can be provided for relevant departments before ice removal, the ice removal operation is facilitated, and the ice removal efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of icing estimation technology, and more specifically, relates to a method for judging icing conditions on power transmission lines. Background Technology

[0002] Icing on transmission lines is one of the more serious natural disasters in my country's power system, often resulting in damage to the mechanical and electrical properties of transmission lines and towers, and causing widespread power outages. Icing accidents seriously threaten the operational safety of my country's power system, making the solution to line icing an urgent issue.

[0003] Traditional anti-icing strategies rely solely on icing warnings or icing monitoring. Traditional icing warning methods primarily obtain icing and snow meteorological information from weather forecasts. In terms of application effectiveness, these methods can provide some guidance for daily line anti-icing maintenance work.

[0004] However, the above methods are time-consuming and labor-intensive, and for some transmission lines, which are usually far from the ground, it is difficult to accurately judge the ice condition by visual inspection. Existing methods for predicting ice conditions mostly derive them from relevant data and current environmental parameters, but the results of these derivations differ significantly from reality and cannot accurately determine the actual situation of the ice layer. Summary of the Invention

[0005] The purpose of this invention is to provide a method for judging ice conditions on power transmission lines, aiming to solve the problem of being unable to accurately judge the actual situation of the ice layer.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for judging ice conditions on transmission lines, comprising:

[0007] When the line is covered with ice, the bending shape of the line is fitted and determined;

[0008] The weight of the ice layer is estimated based on the curvature of the line and the changes in stress and strain on the line, as well as relevant historical data.

[0009] The volume of ice within a certain range is determined using a monitoring instrument, and the density of the ice is determined based on the determined volume and the weight of the ice in the corresponding area.

[0010] In one possible implementation, fitting and determining the bending shape of the line includes:

[0011] A detector is installed on the line to determine the change in the bending angle of the detector's installation position before and after icing.

[0012] In one possible implementation, after determining the change in the bending angle of the detector's installation position before and after icing, the process includes:

[0013] By fitting the installation location and the connection points between the two ends of the line and the corresponding two towers, the bending shape of the line over its entire length is determined.

[0014] In one possible implementation, fitting the bending shape of the line over its entire length includes:

[0015] The detector includes two position sensors at different heights, both mounted on the line;

[0016] The host computer fits the curvature of the line based on the position information returned by the two position sensors, combined with the position of the position sensors relative to the tower and the connection point between the tower and the line.

[0017] In one possible implementation, inferring the weight of the icing by means of changes in stress and strain along the line and relevant historical data includes:

[0018] Based on the current curvature of the line, multiple cases are retrieved from the historical data;

[0019] Multiple cases were simulated for icing in the host computer. The host computer picked up the stress and strain values ​​at the corresponding positions and compared them with the stress and strain values ​​at the same positions on the line. When the two were the same, the case was taken as the icing situation of the line and the weight of the icing in the corresponding range was determined.

[0020] In one possible implementation, simulating icing in the host computer for each of the multiple cases includes:

[0021] A model of the circuit is constructed within the host computer, and the model is made to deform in the same way as the circuit under the same load.

[0022] The ice thickness and length corresponding to the case are set on the model to cause the model to deform.

[0023] In one possible implementation, determining the volume of ice accumulation within a certain range using a monitoring instrument includes:

[0024] Before and after icing, multiple data points within the same range are acquired using a monitoring instrument, and then the data are compared and analyzed to determine the thickness of the icing.

[0025] In one possible implementation, determining the thickness of the ice layer by comparing and analyzing the data includes:

[0026] The monitoring instrument takes pictures of the line before icing and pictures of the ice covering the same area after icing.

[0027] The outline of the ice-covered area is extracted from the image, and the actual size of the outline is determined by combining the distance of the outline from the shooting point.

[0028] In one possible implementation, determining the actual size of the contour by combining the distance of the contour from the shooting point includes:

[0029] By taking pictures with cameras on the tower, and based on the number of pixels occupied by the line in the picture at the same location before icing, the actual size of the outline after icing is determined, and then the volume of the ice is calculated.

[0030] In one possible implementation, the case is taken as an icing situation of the line, and the weight of the icing within the corresponding range is determined as follows:

[0031] Set shooting points at corresponding positions on the model, and make the coverage area of ​​the shooting points the same as the coverage area of ​​the camera;

[0032] After the case simulation is completed, the corresponding images are obtained from the host computer. The images obtained from the host computer are compared with the images taken by the camera to determine whether the case is close to the real situation.

[0033] The beneficial effects of the transmission line icing condition judgment method provided by this invention are as follows: Compared with the prior art, in the transmission line icing condition judgment method of this invention, when the line is covered with ice, the line itself will bend due to the weight of the ice. At this time, the bending shape of the line is fitted and determined. Based on the fitted bending condition of the line, and by using the stress and strain on the line and relevant historical data, the weight of the ice is inferred.

[0034] Once the weight is determined, the volume of ice within a certain range is identified using a monitoring instrument. The density of the ice can then be estimated from the volume and weight. In this application, the actual ice situation can be effectively predicted through analysis and calculation, thus providing relevant departments with relatively accurate data support before de-icing, facilitating de-icing operations and improving de-icing efficiency. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart of a method for judging ice conditions on power transmission lines provided in an embodiment of the present invention. Detailed Implementation

[0037] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0038] Please see Figure 1 The method for judging ice conditions on transmission lines provided by this invention will now be described. The method for judging ice conditions on transmission lines includes:

[0039] When the line becomes icy, the bending shape of the line is fitted and determined.

[0040] The weight of the ice accumulation was estimated based on the curvature of the railway line and the changes in stress and strain along the line, as well as relevant historical data.

[0041] The volume of ice within a certain range is determined by the monitoring instrument, and the density of the ice is determined based on the determined volume and the weight of the ice in the corresponding area.

[0042] The beneficial effects of the transmission line icing condition judgment method provided by this invention are as follows: Compared with the prior art, in the transmission line icing condition judgment method of this invention, when the line is covered with ice, the line itself will bend due to the weight of the ice. At this time, the bending shape of the line is fitted and determined. Based on the fitted bending condition of the line, and by using the stress and strain on the line and relevant historical data, the weight of the ice is inferred.

[0043] Once the weight is determined, the volume of ice within a certain range is identified using a monitoring instrument. The density of the ice can then be estimated from the volume and weight. In this application, the actual ice situation can be effectively predicted through analysis and calculation, thus providing relevant departments with relatively accurate data support before de-icing, facilitating de-icing operations and improving de-icing efficiency.

[0044] Currently, overhead transmission lines typically range from several kilometers to tens of kilometers in length, with some ultra-high-voltage lines reaching hundreds or even thousands of kilometers. Relying on manual inspections presents challenges such as high personnel costs, low economic efficiency, and inaccurate measurement data. Furthermore, atmospheric environmental parameter monitoring based on weather forecasting technology is also used, but its highest resolution is 3km x 3km, far exceeding the span of conventional transmission line towers, making it difficult to accurately locate ice conditions.

[0045] However, traditional anti-icing strategies have many problems. In terms of power, traditional monitoring devices generally use solar power plus batteries, requiring battery replacement every 1-2 years. Regarding communication, they use wireless communication, which is highly susceptible to electromagnetic interference in the strong magnetic field environment of transmission lines, and stable signals are difficult to obtain in remote and terrain-complex areas, resulting in poor communication quality. Environmentally, traditional monitoring devices are installed on transmission line towers or insulators, exposed to complex and harsh environments, significantly reducing their lifespan. In terms of monitoring coverage, a single device can only monitor the status of 1-2 towers. To monitor the entire line, a monitoring device needs to be installed on every iced tower, increasing overall cost and requiring pole-mounting for installation.

[0046] Therefore, in related technologies, monitoring icing on transmission lines is difficult and has low accuracy, making it impossible to detect icing in real time and carry out maintenance, resulting in low monitoring efficiency.

[0047] Under certain weather conditions, ice crystals accumulate around power transmission lines. Icing increases the load on power lines and towers, alters the circular cross-sectional shape of the power lines, and increases the windward area, making them prone to unstable vibrations. This can cause events such as tripping, flashover, torsion, line breakage, and pole collapse, resulting in large-scale power outages.

[0048] Low visibility at the site affects the results of manual ice observation. When cold air from the north moves southward and meets warm, moist air from the south, a cold front forms, creating a large amount of ice crystals and snowflakes in the air, significantly reducing visibility in the surrounding environment. This is precisely the period when icing on transmission lines increases most rapidly. However, due to low visibility, ice prevention personnel generally report that they cannot clearly see the icing situation on the conductors and ground wires at higher points on the towers during manual ice observation, and can only rely on estimations. Near the ground, due to the insulating effect of vegetation and geothermal heat, icing is basically not observable, making manual ice observation difficult.

[0049] There is a significant temperature difference between the upper part of the tower and its base. Artificial ice observation is mainly conducted near the base of the tower, while the actual conductor is located at the upper part. This temperature difference significantly affects the icing process at each level. Experience shows that, generally, when a cold wave passes, icing occurs first at the upper part of the tower, while icing at the base is delayed by 1-2 days. When the cold wave subsides, the ice melts and detaches more quickly at the upper part of the tower, while natural melting at the base takes longer. This phenomenon presents certain difficulties for artificial ice observation.

[0050] Currently, there are three main methods for monitoring icing on overhead power lines. First, establishing icing observation stations. This method requires staff to collect icing samples to measure icing thickness and density. While manual measurement is accurate, it lacks automation, is inconvenient, and is not suitable for large-scale use. Second, measuring parameters such as line inclination, sag, and meteorological information, and deriving icing thickness using formulas. However, due to the overall length of the lines, it is impossible to accurately measure specific parameters such as sag, leading to inaccurate results. Third, capturing icing images with cameras. This method collects icing images and transmits the image information wirelessly to a computer at the monitoring center. The images provide insight into the icing situation and allow for assessment of the severity of the damage. However, this method only collects icing images without further analysis or providing crucial parameters such as icing thickness. The severity of the icing damage relies solely on visual assessment, lacking scientific rigor.

[0051] In some embodiments of the transmission line icing condition assessment method provided in this application, fitting and determining the bending shape of the line includes:

[0052] Detectors are installed on the line to determine the change in the bending angle of the detector's installation location before and after icing.

[0053] Typically, power lines are erected between two adjacent towers. Due to their own weight and other factors, the lines have an arc-shaped structure, meaning the middle section is lower and the ends are higher. To accurately predict ice conditions, current technologies often rely on historical data, combining it with currently collected parameters to make reasonable inferences about the current ice conditions along the power line.

[0054] However, it should be noted that the prediction methods in the existing technology are only inferences about the ice layer based on historical data and neural networks. However, since there are differences between historical data and the actual situation, and the formation of ice layer is a dynamic process in which environmental parameters are constantly changing, the final results will differ greatly from the actual situation, thus making it impossible to make accurate and effective judgments.

[0055] For the reasons mentioned above, a detector is installed on the line in this application. Because the shape and bending angle of the line will be different when the degree of icing on the line is different, the bending angle of the current line can be determined by the detector. Since the total length of the entire line is known, the curvature of the entire line can also be calculated.

[0056] In some embodiments of the transmission line icing assessment method provided in this application, after determining the change in the bending angle of the detector installation position before and after icing by using the detector, the method includes:

[0057] By fitting the installation location and the connection points at both ends of the line and the corresponding two towers, the bending shape of the line over its entire length is obtained.

[0058] It should be noted that the spacing between the towers is fixed, and since icing of the lines mostly occurs during winter and other periods of low temperature, this application does not consider the impact of different temperatures on the total length of the line, that is, it does not consider the thermal expansion and contraction of the line due to temperature changes.

[0059] In practical applications, it has been found that due to the long length of the lines and the significant weight of the lines themselves combined with the ice when icing occurs, the presence of ice causes the lines to undergo expansion and contraction. Ultimately, the greater the thickness of the ice layer, the greater the degree of bending of the lines.

[0060] To enable the detector to detect line angles, this application includes two position sensors installed on the line, spaced a certain distance apart and at different heights. Both position sensors upload their current position and angle information to a host computer. Based on this feedback and the sensor's relative position to the line, the host computer can infer the line's bending condition when icing is present.

[0061] Because the installation points of the lines and towers are fixed, and the spacing between the towers is determined, the entire line can be fitted based on the position information fed back by the two position sensors and the actual positions of the position sensors installed on the lines.

[0062] In some embodiments of the transmission line icing condition assessment method provided in this application, the fitted bending shape of the line over its entire length includes:

[0063] The detector consists of two position sensors at different heights, both mounted on the line.

[0064] The host computer uses the position information transmitted back by the two position sensors, combined with the position of the position sensors relative to the tower and the connection point between the tower and the line, to fit the bending shape of the line.

[0065] In practical applications, the host computer receives data from the two position sensors in real time. When there is no icing, an initial model of the line is constructed in the host computer through actual measurements and other methods. At this time, the data corresponding to each sensor can be regarded as the initial data. The relative positions between the two towers are determined, which makes the position of the connection point between the line and the towers also determined.

[0066] When icing occurs, the data from all sensors will change to some extent. Since the data from the two position sensors are uploaded in real time, the host computer can construct two constant position points between the line and the two towers, and combine them with the position information returned by the two position sensors to fit the current line model. That is, by using the four completely determined points, a corresponding curve passing through the above four points can be fitted.

[0067] Based on changes in the line model, historical data, and methods such as finite element analysis, a precise assessment of the current icing situation can be made. Once the curvature of the line is determined, the weight of the entire ice layer—that is, the total weight of the ice layer—can be roughly estimated based on historical data and finite element analysis. Because different total weights of ice layers will lead to different curvatures of the line.

[0068] In some embodiments of the transmission line icing assessment method provided in this application, the weight of the ice accumulation is inferred by analyzing changes in stress and strain on the line and relevant historical data, including:

[0069] Based on the current curvature of the line, multiple cases were retrieved from historical data.

[0070] Multiple cases were simulated for icing in the host computer. The host computer picked up the stress and strain values ​​at the corresponding locations and compared them with the stress and strain values ​​at the same locations on the line. When the two were the same, the case was taken as the icing situation of the line and the weight of the icing in the corresponding range was determined.

[0071] While historical data and finite element analysis have some reference value, the actual icing situation of a railway line is easily affected by many random factors, such as wind direction, wind speed, and humidity on that day. Based on the above issues, directly using the calculated icing condition corresponding to the curvature of the railway line as the final icing result may result in a large deviation from the actual situation.

[0072] To improve data reliability, stress and strain sensors can be installed along the line beforehand. At least two sensors should be installed, typically one at the end of the line near the tower and the other in the middle. These two locations are the easiest to determine on the model even if icing conditions change significantly.

[0073] After assessing the icing condition based on historical data and finite element analysis, the corresponding stress and strain are calculated at the model's locations. If the deviation between the model's values ​​and actual measurements does not exceed a threshold, the predicted ice condition data is used as the final result. If the deviation is significant, simulations are performed on a host computer based on the model's shape and data from stress and strain sensors. This simulates various icing conditions, using the data from the stress and strain sensors as the final standard, generating an ice condition case that matches the actual sensor results. This case is then preliminarily compared with the actual situation.

[0074] In some embodiments of the transmission line icing condition assessment method provided in this application, multiple cases are simulated for icing in the host computer, including:

[0075] A model of the circuit is constructed in the host computer, and the model is made to deform in the same way as the circuit under the same load.

[0076] Set the ice thickness and length corresponding to the case study onto the model to cause the model to deform.

[0077] The above settings enable the model in the host computer to produce the same deformation under the same scenario, thereby providing strong data support for calculating the actual situation of icing.

[0078] In some embodiments of the transmission line icing assessment method provided in this application, the volume of ice covering a certain range is determined by a monitoring instrument, including:

[0079] Before and after icing, multiple data points within the same range are acquired using a monitoring instrument, and then the data are compared and analyzed to determine the thickness of the icing.

[0080] When the outside temperature is low, ice will accumulate on the power lines. The density and distribution of the ice layer will vary depending on the conditions. Data collected by position sensors can estimate the total weight of the ice layer to some extent, but it is impossible to effectively monitor detailed information such as the distribution and density of the ice layer. This is a problem that urgently needs to be solved, because different ice densities require different de-icing methods.

[0081] To avoid the aforementioned problems, this application includes a monitoring device installed on the corresponding tower. The monitoring device is used to scan the line conditions within a certain range. Before the temperature drops, the monitoring device first acquires data on the line when there is no icing. As the temperature drops and the ice layer on the line gradually thickens, the monitoring device acquires data on the current line within the same range, and then compares the data from different times to obtain the distribution and thickness of the ice layer.

[0082] Once the distribution and thickness of the ice layer are determined, the total weight of the entire ice layer has already been inferred through the position sensors. Based on the total weight, distribution, and thickness, the density of the ice layer can then be obtained, providing a final, intuitive data reference for the de-icing work.

[0083] In some embodiments of the transmission line icing assessment method provided in this application, the thickness of the ice layer is determined by comparing and analyzing the data.

[0084] Images were taken by a monitoring device showing the line before icing and the same area after icing.

[0085] Extract the outline of the ice-covered area from the image, and determine the actual size of the outline by combining the distance of the outline from the shooting point.

[0086] In order to conduct a more comprehensive and accurate analysis of the ice layer, it is necessary to determine the changes in the ice layer after it is covered with ice, and to determine the shape of the ice layer based on the degree of change without direct measurement.

[0087] To achieve the aforementioned technical effects, if the monitoring device is set to a laser scanner, although the shape of the ice layer can be inferred more intuitively and accurately, current technology limits the maximum detection range of laser scanners and their large size, making them inconvenient to install on poles. To address these issues, the monitoring device in this application includes a camera that captures images before and after icing within the same area.

[0088] It is important to note that the camera captured the same field of view in both shots. More importantly, the presence of ice causes the power line to bend and deform, resulting in slight changes in the shape of the line in the images taken before and after icing. However, the vertical deformation distance at the same location is predictable, and the closer to the tower, the smaller the downward deformation.

[0089] In practical applications, the outer diameter of the line remains constant. The farther away from the camera, the smaller the number of pixels it occupies in the image, and correspondingly, the smaller the number of pixels occupied by the ice layer. Based on this principle, the outer contour of the ice layer is first extracted. After the outer contour is extracted, the circumferential thickness of the ice layer is determined based on the size of the line relative to the ice layer. Using an image of the line taken by the camera before it became covered with ice as a reference, the number of pixels occupied by the line at different locations in the image varies, therefore, the number of pixels occupied by ice of the same thickness at different locations also varies. Therefore, by using the image acquired by the camera and scaling it up proportionally, the thickness of the ice layer within the camera's view can be obtained, and the shape of the ice layer can be fitted.

[0090] In some embodiments of the transmission line icing condition assessment method provided in this application, determining the actual size of the contour by combining the distance between the contour and the shooting point includes:

[0091] By taking pictures with cameras on the towers, and based on the number of pixels the line occupied in the picture before icing at the same location, the actual size of the outline after icing is determined, and then the volume of the ice is calculated.

[0092] In practical applications, the outline of the ice layer can be extracted from images captured by a camera by judging the brightness values ​​of individual pixels and setting the approximate direction of the ice layer. Once the approximate outline is determined, an ice layer closer to the camera is selected as a reference position. Previous images show the pixel size of the line in the image if there is no ice layer present. Since the outer diameter of the line is known, the proportional relationship between the actual length and the number of pixels is established. Based on this proportional relationship, the actual shape and corresponding thickness of the ice layer can then be determined.

[0093] Once the shape and thickness are determined, the volume of the ice layer within the captured area can be determined by combining the extracted ice layer outline. Then, the total weight of the ice layer within the current area can be determined in the host computer, and the density of the ice layer can be obtained.

[0094] In some embodiments of the transmission line icing condition assessment method provided in this application, a case is used as the icing condition of the line, and the weight of the icing within the corresponding range is determined, including:

[0095] Set shooting points at the corresponding locations on the model, and ensure that the coverage area of ​​the shooting points is the same as the coverage area of ​​the camera.

[0096] After the case simulation is completed, the corresponding images are obtained from the host computer. The images obtained from the host computer are compared with the images taken by the camera to determine whether the case is close to the real situation.

[0097] Because the entire route is quite long and the camera's field of view is limited, in order to determine the ice condition along the entire length of the route, it is necessary to combine historical data with the actual data collected to make a final judgment.

[0098] To explain in more detail, we first obtain historical data on the distribution and thickness of ice layers in different scenarios. Then, based on the actual conditions of the route currently being collected, we identify multiple candidate cases from the historical data, using these actual conditions as the final determining factor. Next, based on images taken by on-site cameras, we can determine information such as the shape of the ice layer within a certain range near the cameras. Based on this information, we can then narrow down and select the candidate cases.

[0099] After the deletion is completed, the corresponding situation is simulated in the host computer. Then, the actual degree of line bending is compared with the simulated bending situation to finally determine the case that best matches the reality. This case is then used as the inferred ice condition.

[0100] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for judging icing conditions of a power transmission line, characterized by, The method comprises the following steps: fitting and determining the bending shape of the line when icing occurs on the line; speculating the weight of the icing according to the bending condition of the line and the change of stress and strain on the line and related historical data; determining the volume of the icing within a certain range by a monitoring instrument, and determining the density of the icing according to the determined volume and the weight of the icing in the corresponding region; the fitting and determining the bending shape of the line comprises: installing a detector on the line, and determining the change of bending angle of the installation position of the detector before and after icing by the detector; after the determining the change of bending angle of the installation position of the detector before and after icing by the detector, the method comprises: fitting the bending shape of the line in the full length condition by the installation position and the connecting points between the two ends of the line and the corresponding two towers; the fitting the bending shape of the line in the full length condition comprises: the detector comprises two position sensors installed on the line at different heights; the host computer fits the bending shape of the line according to the position information returned by the two position sensors, in combination with the positions of the position sensors relative to the towers and the connecting points between the towers and the line.

2. The method of claim 1, wherein the speculating the weight of the icing according to the bending condition of the line and the change of stress and strain on the line and related historical data comprises: searching for multiple cases in the historical data according to the current bending shape of the line; performing icing simulation on the multiple cases in the host computer respectively, picking up the stress and strain values of the corresponding positions by the host computer, and comparing the stress and strain values with the stress and strain values of the same positions on the line; when they are the same, the case is determined as the icing condition of the line, and the weight of the icing in the corresponding range is determined.

3. The method of claim 2, wherein the performing icing simulation on the multiple cases in the host computer respectively comprises: building a model of the line in the host computer, and making the model have the same deformation as the line under the same load condition; setting the corresponding ice thickness and length in the case on the model, so that the model deforms.

4. The method of claim 3, wherein the determining the volume of the icing within a certain range by a monitoring instrument comprises: acquiring multiple data in the same range before and after icing by a monitoring instrument, and then comparing and analyzing the data to determine the thickness of the icing.

5. The method of claim 4, wherein the then comparing and analyzing the data to determine the thickness of the icing comprises: taking pictures containing the line before icing and pictures containing the icing in the same range after icing by the monitoring instrument; picking up the outline of the icing from the pictures, and determining the actual size of the outline in combination with the distance of the outline from the shooting point.

6. The method of claim 5, wherein the determining the actual size of the outline in combination with the distance of the outline from the shooting point comprises: taking pictures by a camera on the tower, determining the actual size corresponding to the outline after icing according to the number of pixel points occupied by the line in the pictures before icing at the same position, and then calculating the volume of the icing.

7. The method of claim 6, wherein The case is taken as icing condition of the line, and a corresponding range of icing weight is determined; A shooting point is set at a corresponding position of the model, and a coverage range of the shooting point is made same as a coverage range of the camera; After the case simulation is completed, a corresponding picture is acquired in the upper computer, the picture acquired in the upper computer is compared with the picture shot by the camera, and whether the case is close to a real condition is judged.

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