Method for detecting icing on a power transmission line

Abstract

The application discloses a kind of transmission line icing detection methods, belong to transmission line field.To solve the transmission line icing by image can only carry out partial icing calculation, cannot judge the influence of icing on the whole line in span, simultaneously improve the applicability of icing detection, the application is by setting first line detection equipment, second line detection equipment, first tower positioning equipment and second tower positioning equipment Multiple sensors.According to the coordinates of multiple sensors, in combination with transmission line parabolic model, real-time obtain line horizontal stress and suspension point vertical stress, and ice-free wind-free and ice-free wind-free conditions, the icing load and icing average thickness of whole span, more comprehensively determine the influence of icing on transmission line.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power transmission lines, in particular to a power transmission line icing detection method. BACKGROUND

[0002] The normal operation of power transmission lines is related to people's daily life and industrial production, and is an important basis for economic development. In recent years, abnormal weather has occurred frequently, and power transmission line icing has occurred frequently. After the power transmission line icing, the sag is easy to increase to cause discharge accidents, the tension is too large to cause line breakage, and more seriously, the tower may be collapsed. Therefore, the icing detection of the power transmission line is particularly important.

[0003] At present, the icing detection of the power transmission line mainly adopts image analysis to determine whether the icing occurs on the conductor, and calculates the icing thickness according to the pixel processing of the edges of the un-iced conductor and the edges of the iced conductor to detect the icing of the power transmission line.

[0004] The image analysis technology is used to detect the icing of the power transmission line, and the detection can only be performed on part of the icing area of the line due to the influence of the image shooting angle and the long line, and the accurate judgment cannot be made on the influence of the icing on the whole line. In addition, the tension detection is used to detect the icing influence on the whole line, and the tension sensor needs to be installed on the tension insulator, which is complex to operate and is not conducive to popularization and application. SUMMARY

[0005] In order to solve the problem that the image analysis can only be used to calculate the partial icing of the power transmission line and cannot be used to judge the influence of the icing on the whole line in the span, and improve the applicability of the icing detection, the present application provides a power transmission line icing detection method, which can obtain the icing load and the average thickness of the icing of the whole span in real time, and more comprehensively determine the influence of the icing on the power transmission line.

[0006] The technical scheme of the present application is as follows:

[0007] A power transmission line icing detection method, first tower positioning equipment and second tower positioning equipment are respectively installed on adjacent first towers and second towers, and first line detection equipment and second line detection equipment are respectively installed on two different positions of a power transmission line between the adjacent first tower and the second tower.

[0008] The first line detection equipment, the second line detection equipment, the first tower positioning equipment and the second tower positioning equipment all include a positioning module, a wireless transmission module and a temperature and humidity detection module, and the first tower positioning equipment and the second tower positioning equipment further include a wind speed detection module.

[0009] The method comprises:

[0010] S10: Real-time detection of environmental temperature, humidity and wind speed through the temperature and humidity detection module and the wind speed detection module, and real-time positioning of the latitude and longitude coordinates of the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device through the positioning module;

[0011] S20: Establishing a space rectangular coordinate system and converting the latitude and longitude coordinates of the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device into three-dimensional space coordinates;

[0012] S30: When the temperature is greater than 0 degrees, the humidity is lower than the set humidity threshold, and the wind speed is less than the set first wind speed threshold, it is judged as no ice and no wind state; The self-weight ratio load of the power transmission line is calculated.

[0013] S40: When the temperature is not greater than 0 degrees, the humidity is not lower than the set humidity threshold, the wind speed is not less than the set first wind speed threshold and not greater than the set second wind speed threshold, it is judged as having ice and no wind state; The ice load and ice thickness of the power transmission line under the ice and no wind state are calculated.

[0014] S50: When the temperature is not greater than 0 degrees, the humidity is not lower than the set humidity threshold, and the wind speed is not less than the set second wind speed threshold, it is judged as having ice and wind state; The ice load and ice thickness of the power transmission line under the ice and wind state are calculated.

[0015] Further, the S20 comprises:

[0016] S21: Establishing a space rectangular coordinate system with the power transmission line suspension point A on the first tower as the origin, along the direction parallel to the power transmission line as the Y axis, along the vertical direction as the Z axis, and along the direction perpendicular to the Y axis and the Z axis as the X axis;

[0017] S22: Converting the latitude and longitude coordinates obtained by the positioning module of the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device into three-dimensional space coordinates according to the established space rectangular coordinate system;

[0018] S23: According to the relative position relationship between the first tower positioning device and the second tower positioning device and the power transmission line suspension points A and B on the first tower and the second tower, the three-dimensional space coordinates of the power transmission line suspension point B on the second tower, the power transmission line span l and the height difference h of the power transmission line suspension points A and B are calculated.

[0019] Further, the S30 comprises:

[0020] S31: Calculating the power transmission line according to the parabolic model to obtain the sag formula of any point of the power transmission line;

[0021]

[0022] wherein y is the Y-axis coordinate of any point of the power transmission line, z is the sag value of the power transmission line when the Y-axis coordinate is y, β is the height difference angle of the power transmission line at the suspension points of the adjacent first tower and second tower, σ0 and γ are the horizontal stress and specific load of the power transmission line respectively;

[0023]

[0024] S32: substituting the three-dimensional space coordinates of the first line detection device and the second line detection device in the ice-free and wind-free state into the sag formula, obtaining the horizontal stress σ0 and the specific load γ of the power transmission line in the ice-free and wind-free state, and calculating the deadweight specific load g of the power transmission line in the ice-free and wind-free state;

[0025] g = γ * A

[0026] wherein A is the cross-sectional area of the power transmission line.

[0027] Further, the S30 further comprises:

[0028] S33: calculating the vertical stresses σ A and σ B of the suspension points A and B of the power transmission line in the ice-free and wind-free state.

[0029]

[0030] wherein l oa and l ob are the horizontal distances from the lowest point of the power transmission line to the suspension points A and B of the power transmission line respectively.

[0031]

[0032]

[0033] Further, the S40 comprises:

[0034] S41: substituting the three-dimensional space coordinates of the first line detection device and the second line detection device in the ice-covered and wind-free state into the sag formula, obtaining the horizontal stress σ1 and the specific load γ1 of the power transmission line in the ice-covered and wind-free state, and calculating the conductor load g2 of the power transmission line in the ice-covered and wind-free state.

[0035] g2 = γ1 * A

[0036] S42: calculating the vertical stresses σ C and σ D of the suspension points A and B of the power transmission line in the ice-covered and wind-free state.

[0037] S43: when When the transmission line is covered with ice and without wind, the ice load g1 is calculated by the formula g2=g+g1, and the ice load g1 is calculated by the formula g1=27.73δ(δ+d)×10 -3 Calculate the ice thickness δ1;

[0038] Where d is the diameter of the transmission line.

[0039] Furthermore, the S50 includes:

[0040] S51: Substituting the three-dimensional spatial coordinates of the first line detection device and the second line detection device in the icy and windy state into the sag formula to obtain the horizontal stress σ2 and the specific load γ2 of the transmission line in the icy and windy state, and calculating the conductor load g3 of the transmission line in the icy and windy state;

[0041] g3=γ2*A

[0042] S42: Calculate the vertical stress σ at the suspension points A and B of the transmission line under ice and wind conditions E , σ F ;

[0043] S44: By formula Calculate the ice load g6 of the transmission line under the conditions of ice and wind, and use the formula g6=27.73δ(δ+d)×10 -3 Calculate the ice thickness δ2;

[0044] Among them, g5=g+g6, g4=0.625v 2 daμ sc ×10 -3 , v is the wind speed, a is the wind pressure unevenness coefficient of the transmission line, μ sc is the wire shape coefficient of the transmission line.

[0045] Furthermore, the method further comprises:

[0046] S60: Compare the horizontal stresses σ0, σ1, and σ2 of the transmission line in the ice-free and windless state, the ice-covered and windy state, and the ice-covered and windy state with the maximum tension F that the transmission line can withstand, and issue a warning signal when σ0, σ1, and σ2 exceed a first set percentage of the maximum tension F.

[0047] Furthermore, the method further comprises:

[0048] S70: The vertical stress σ of the transmission line suspension points A and B in the ice-free and windless state, the ice-free and windy state, and the ice-windy state. A , σ B , σ C , σ D , σ E , σF Compare them with the maximum pressure F1 that the insulator can withstand. A , σ B , σ C , σ D , σ E , σ F When the pressure exceeds the second set percentage of the maximum pressure F1, an early warning signal is issued.

[0049] The present invention has the following beneficial effects:

[0050] To address the problem of only being able to calculate partial ice coverage on transmission line images and failing to determine the impact of ice coverage on the entire line within a span, while also improving the applicability of ice coverage detection, the present invention employs multiple sensors, including a first line detection device, a second line detection device, a first tower positioning device, and a second tower positioning device. Based on the coordinates of these sensors and combined with a parabolic model of the transmission line, the system can obtain real-time horizontal stress on the line and vertical stress at the suspension point, as well as ice load and average ice thickness for the entire span under both ice-free and windless conditions, enabling a more comprehensive assessment of the impact of ice coverage on the transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the physical equipment on which the power transmission line icing detection method of the present invention is based;

[0052] Figure 2 The figure is a flow chart of the method for detecting ice coating on a power transmission line according to the present invention. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0054] The embodiment of the present invention provides a method for detecting ice coating on a transmission line. Figure 1 As shown, a first tower positioning device 1 and a second tower positioning device 2 are respectively installed on the adjacent first tower 100 and the second tower 200, and a first line detection device 3 and a second line detection device 4 are respectively installed at two different positions of a transmission line 5 between the adjacent first tower 100 and the second tower 200.

[0055] The first line detection device 3, the second line detection device 4, the first tower positioning device 1, and the second tower positioning device 2 all include a positioning module (e.g., an RTK positioning module), a wireless transmission module, and a temperature and humidity detection module. If necessary, they also include a wireless transmission module, a power module, etc. The first tower positioning device 1 and the second tower positioning device 2 also include a wind speed detection module.

[0056] The first line detection device 3 and the second line detection device 4 are installed on the power transmission line, wherein the RTK positioning module provides millimeter-level positioning, the temperature and humidity module detects the temperature and humidity around the line, the power module is composed of mutual inductance magnetic core, solar panel and lithium battery, the line mutual inductance obtains the energy required for the device to work, and the wireless transmission module can transmit the device positioning information, temperature and humidity information and power information to the data server through the 4G / 5G communication mode.

[0057] The first tower positioning device 1 and the second tower positioning device 2 are respectively installed on the first tower 100 and the second tower 200 on the two sides, the horizontal distance a, the vertical distance b and the distance e in the line direction of the first tower positioning device 1 and the horizontal distance c, the vertical distance d and the distance f in the line direction of the second tower positioning device 2 and the wire suspension point B on one side are measured by the measuring instrument, wherein the RTK positioning device provides millimeter-level positioning information, the temperature and humidity module obtains the ambient temperature and humidity, the wind speed detection module can detect the ambient wind speed information, the power module is composed of a solar panel and a lithium battery, and the wireless transmission module can transmit the positioning information, the ambient temperature and humidity information, the wind speed information and the device power information to the data server through the 4G / 5G communication mode.

[0058] Based on the above structure, the icing detection method is as follows Figure 2 The method comprises the following steps.

[0059] S10: Real-time detection of ambient temperature, humidity and wind speed is performed through the temperature and humidity detection module and the wind speed detection module, and real-time positioning of the latitude and longitude coordinates of the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device is performed through the positioning module.

[0060] S20: A space rectangular coordinate system is established, and the latitude and longitude coordinates of the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device are converted into three-dimensional space coordinates.

[0061] One implementation mode of the step comprises the following steps.

[0062] S21: A space rectangular coordinate system is established with the wire suspension point A on the first tower as the origin, the direction parallel to the power transmission line as the Y axis, the vertical direction as the Z axis, and the direction perpendicular to the Y axis and the Z axis as the X axis, as shown in Figure 1 .

[0063] S22: The latitude and longitude coordinates obtained by the positioning module of the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device are converted into three-dimensional space coordinates according to the established space rectangular coordinate system.

[0064] For example, the three-dimensional space coordinates of the first tower positioning device 1, the second tower positioning device 2, the first line detection device 3, and the second line detection device 4 are (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), and (x4, y4, z4) respectively.

[0065] S23: According to the relative position relationship between the first tower positioning device and the second tower positioning device and the suspension points A and B of the power transmission line on the first tower and the second tower, the three-dimensional space coordinates of the suspension point B of the power transmission line on the second tower, the span l of the power transmission line, and the height difference h of the suspension points A and B of the power transmission line are calculated.

[0066] The horizontal distance a, the vertical distance b, and the distance e in the line direction of the first tower positioning device 1 from the suspension point A of the conductor on one side are known, and the horizontal distance c, the vertical distance d, and the distance f in the line direction of the second tower positioning device 2 from the suspension point B of the conductor on one side are known. The translation coordinates of the line suspension points A and B on both sides of the tower are (x1+a, y1-e, z1+b) and (x2+c, y2+f, z2+d).

[0067] According to the coordinates of the suspension points A and B, the line detection span l can be obtained. The height difference h of the suspension points A and B is |z2+d-z1-b|.

[0068] S30: When the temperature is greater than 0 degrees, the humidity is lower than the set humidity threshold, and the wind speed is less than the set first wind speed threshold, it is judged as no ice and no wind state; the dead load ratio of the power transmission line is calculated.

[0069] For example, the humidity threshold can be 85%, and the first wind speed threshold can be a value close to 0.

[0070] As an implementation manner, the specific process of S30 includes:

[0071] S31: The power transmission line is calculated according to the parabolic model to obtain the sag formula of any point of the power transmission line.

[0072]

[0073] Wherein, y is the Y-axis coordinate of any point of the power transmission line, z is the sag value of the power transmission line when the Y-axis coordinate is y, β is the height difference angle of the power transmission line at the suspension points of the adjacent first tower and second tower, σ0 and γ are the horizontal stress and the load ratio of the power transmission line respectively.

[0074]

[0075] S32: the three-dimensional space coordinates of the first line detection device and the second line detection device in the ice-free and wind-free state are substituted into the sag formula to obtain the horizontal stress σ0 and the specific load γ of the power transmission line in the ice-free and wind-free state, and the deadweight specific load g of the power transmission line in the ice-free and wind-free state is calculated.

[0076] g = γ * A

[0077] wherein, if the coordinate system is established according to Figure 1 , the y value of the three-dimensional space coordinates of the first line detection device and the second line detection device is substituted into the parameter y of the sag formula, and the absolute value of the z value of the three-dimensional space coordinates of the first line detection device and the second line detection device is substituted into the parameter z of the sag formula. Since β can be calculated according to the triangular function through the span l of the power transmission line and the height difference h of the suspension points A and B of the power transmission line, the horizontal stress σ0 and the specific load γ of the power transmission line in the ice-free and wind-free state can be obtained after being substituted into the sag formula.

[0078] A is the cross-sectional area of the power transmission line, which can be obtained through the line construction drawing, so the deadweight specific load g of the power transmission line can be obtained.

[0079] S33: the vertical stress σ A , σ B of the suspension points A and B of the power transmission line in the ice-free and wind-free state is calculated.

[0080]

[0081] wherein, l oa and l ob are the horizontal distances from the lowest point o of the power transmission line to the suspension points A and B of the power transmission line, respectively.

[0082]

[0083] This step uses the horizontal distance formula from the lowest point of the line to the suspension point, and can obtain l oa , l ob . The vertical component stress formula of the suspension point of the power transmission line is a slanting parabola equation The vertical stresses σ A , σ B of the two points A and B under the condition of no wind and no ice can be obtained.

[0084] S40: when the temperature is not greater than 0 degrees, the humidity is not lower than the set humidity threshold, the wind speed is not less than the set first wind speed threshold and not greater than the set second wind speed threshold, it is judged that it is in the ice-free and wind-free state; the ice load and the ice thickness of the power transmission line in the ice-free and wind-free state are calculated.

[0085] For example, when the temperature is not greater than 0 degrees and the humidity is not lower than the set humidity threshold, the line icing is prone to occur, and the second wind speed threshold can be taken as a value of about 1 m / s.

[0086] One specific implementation of S40 includes:

[0087] S41: The three-dimensional space coordinates of the first line detection device and the second line detection device in the ice-no-wind state are substituted into the sag formula to obtain the horizontal stress σ1 and the specific load γ1 of the power transmission line in the ice-no-wind state, and the conductor load g2 of the power transmission line in the ice-no-wind state is calculated.

[0088] g2=γ1*A

[0089] This step is similar to S32, except that the coordinates in the ice-no-wind state are substituted, and the horizontal stress σ1 and the specific load γ1 in the ice-no-wind state are obtained. Then, based on the cross-sectional area A of the power transmission line, the conductor load g2 in the ice-no-wind state can be calculated.

[0090] S42: The vertical stresses σ C , σ D of the suspension points A and B of the power transmission line in the ice-no-wind state are calculated.

[0091] This step is similar to S33, except that the specific load in the formula is γ1, and the specific process is not described again.

[0092] S43: When , the icing load g1 of the power transmission line in the ice-no-wind state is calculated by the formula g2=g+g1, and the icing thickness δ1 is calculated by the formula g1=27.73δ(δ+d)×10 -3 .

[0093] Wherein, d is the diameter of the power transmission line, which can be obtained from the line construction drawing.

[0094] When , the vertical stress of the line increases, and the wind load caused by the wind speed is small at this time. The conductor load is mainly composed of the self-weight load and the icing load, i.e. g2=g+g1. g1 is the icing load, and g is the specific load of the conductor weight, so that the icing load g1 is obtained.

[0095] The average thickness δ1 of the icing in the span under this environment is calculated by the formula g1=27.73δ(δ+d)×10 -3 , δ is the wire icing thickness, and d is the conductor diameter.

[0096] S50: When the temperature is not greater than 0 degrees, the humidity is not lower than the set humidity threshold, and the wind speed is not less than the set second wind speed threshold, it is judged to be in the ice-wind state; the icing load and the icing thickness of the power transmission line in the ice-wind state are calculated.

[0097] One specific implementation of S50 includes:

[0098] S51: Substitute the three-dimensional space coordinates of the first line detection device and the second line detection device in the ice and wind state into the sag formula, obtain the horizontal stress σ2 and the specific load γ2 of the power transmission line in the ice and wind state, and calculate the conductor load g3 of the power transmission line in the ice and wind state.

[0099] g3 = γ2 * A

[0100] This step is similar to S32 and will not be repeated.

[0101] S42: Calculate the vertical stress σ E , σ F of the power transmission line suspension points A and B in the ice and wind state.

[0102] This step is similar to S33 and will not be repeated.

[0103] S44: Calculate the ice load g6 of the power transmission line in the ice and wind state by the formula , and calculate the ice thickness δ2 by the formula g6 = 27.73δ (δ + d) * 10 -3 .

[0104] Wherein, g5 = g + g6, g4 = 0.625v 2 daμ sc * 10 -3 , v is the wind speed, a is the wind pressure uneven coefficient of the power transmission line, μ sc is the wire shape coefficient of the power transmission line, and a and μ sc can be obtained from the Technical Specification for Design of Overhead Transmission Line.

[0105] In order to solve the problem that the ice on the power transmission line can only be calculated by image, the influence of the ice on the whole line in the span cannot be judged, and the applicability of ice detection is improved, the present application sets multiple sensors such as the first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device. According to the coordinates of the multiple sensors, the horizontal stress of the line and the vertical stress of the suspension point are obtained in real time in combination with the parabolic model of the power transmission line, and the ice load and the average ice thickness of the whole span under the conditions of ice without wind and no ice without wind are obtained, so that the influence of the ice on the power transmission line is more comprehensively determined.

[0106] Meanwhile, the present application can also make alarm prompt when the horizontal stress and the vertical stress exceed the set stress threshold, and make rapid response. The specific method includes:

[0107] S60: compare the horizontal stress σ0, σ1, σ2 of the power transmission line in the no-ice no-wind state, the ice no-wind state and the ice with wind state respectively with the maximum tension F that the power transmission line can withstand, and send a warning signal to the server when σ0, σ1, σ2 exceeds the first set percentage of the maximum tension F.

[0108] S70: compare the vertical stress σ A , σ B , σ C , σ D , σ E , σ F of the power transmission line suspension points A, B in the no-ice no-wind state, the ice no-wind state and the ice with wind state respectively with the maximum pressure F1 that the insulator can withstand, and send a warning signal to the server when σ A , σ B , σ C , σ D , σ E , σ F exceeds the second set percentage of the maximum pressure F1.

[0109] The power transmission line icing detection system further comprises a data server and a monitoring platform. The data server mainly receives line detection equipment, tower positioning equipment, and monitoring equipment data information, calculates various temperatures, humidities, wind speeds, whether icing conditions, power transmission line horizontal stress and two-side hanging point horizontal stress under icing conditions, and icing thickness under icing conditions, icing load and icing wind load alternating changes under icing with wind conditions according to the power transmission line icing detection method. The server performs data storage according to the platform specified "storage days" instruction. The server receives the platform set "conductor stress threshold" and "hanging point stress threshold", compares the actual calculated conductor horizontal stress with the conductor maximum tension percentage and the conductor stress threshold, and sends an alarm signal if it exceeds the set threshold. Similarly, if the hanging point stress exceeds the set threshold, an alarm signal is sent.

[0110] The monitoring platform is used to display the running state of the line detection equipment, tower positioning equipment, and monitoring equipment, set the working frequency of the three devices, set the data server data retention date, display the conductor ice and icing no-wind, icing with wind line horizontal stress and line hanging point vertical stress under icing with wind conditions, icing thickness under icing no-wind line, and icing load and icing wind load change under icing with wind conditions, set the horizontal stress alarm threshold and the hanging point vertical stress alarm threshold, and send an alarm after receiving the alarm information to remind the monitoring personnel of stress overrun.

[0111] The above is the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles described in the present application, can also be made several improvements and refinements, these improvements and refinements should also be considered the scope of protection of the present application.

Claims

1. A method for detecting ice coating on a power transmission line, characterized in that: A first pole tower positioning device and a second pole tower positioning device are respectively installed on adjacent first pole towers and a second pole tower positioning device, and a first line detection device and a second line detection device are respectively installed at two different positions of a transmission line between the adjacent first pole towers and the second pole towers; The first line detection device, the second line detection device, the first tower positioning device and the second tower positioning device each include a positioning module, a wireless transmission module and a temperature and humidity detection module, and the first tower positioning device and the second tower positioning device also include a wind speed detection module; The method comprises: S10: Detecting the ambient temperature, humidity, and wind speed in real time through the temperature and humidity detection module and the wind speed detection module, and locating the longitude and latitude coordinates of the first line detection device, the second line detection device, the first tower positioning device, and the second tower positioning device in real time through the positioning module; S20: Establishing a spatial rectangular coordinate system, and converting the longitude and latitude coordinates of the first line detection device, the second line detection device, the first tower positioning device, and the second tower positioning device into three-dimensional spatial coordinates; S30: When the temperature is greater than 0 degrees, the humidity is lower than the set humidity threshold, and the wind speed is lower than the set first wind speed threshold, it is determined to be an ice-free and windless state; and the deadweight load ratio of the transmission line is calculated; S40: When the temperature is not greater than 0 degrees, the humidity is not less than the set humidity threshold, and the wind speed is not less than the set first wind speed threshold and not greater than the set second wind speed threshold, it is determined that there is ice but no wind; and the ice load and ice thickness of the transmission line in the ice but no wind state are calculated; S50: When the temperature is not greater than 0 degrees, the humidity is not less than the set humidity threshold, and the wind speed is not less than the set second wind speed threshold, it is determined that there is ice and wind; and the ice load and ice thickness of the transmission line in the ice and wind state are calculated; The S20 includes: S21: Establish a spatial rectangular coordinate system with the transmission line suspension point A on the first tower as the origin, the direction parallel to the transmission line as the Y axis, the vertical direction as the Z axis, and the direction perpendicular to the Y axis and the Z axis as the X axis; S22: converting the longitude and latitude coordinates obtained by positioning modules of the first line detection device, the second line detection device, the first tower positioning device, and the second tower positioning device into three-dimensional spatial coordinates according to the established spatial rectangular coordinate system; S23: Calculate the three-dimensional coordinates of the transmission line suspension point B on the second tower, the transmission line span l, and the height difference h between the transmission line suspension points A and B based on the relative positional relationship between the first tower positioning device and the second tower positioning device and the transmission line suspension points A and B on the first tower and the second tower; The S30 includes: S31: Calculate the transmission line according to the parabola model to obtain the sag formula of any point on the transmission line; Where y is the Y-axis coordinate of any point on the transmission line, z is the sag value of the transmission line when the Y-axis coordinate is y, β is the height difference angle between the suspension points of the transmission line at the first and second adjacent towers, σ0 and γ are the horizontal stress and specific load of the transmission line, respectively. S32: Substituting the three-dimensional spatial coordinates of the first line detection device and the second line detection device in the ice-free and wind-free state into the sag formula to obtain the horizontal stress σ0 and the specific load γ of the transmission line in the ice-free and wind-free state, and calculating the deadweight specific load g of the transmission line in the ice-free and wind-free state; g=γ*A Where A is the cross-sectional area of ​​the transmission line; The S30 further includes: S33: Calculate the vertical stress σ at the suspension points A and B of the transmission line in the absence of ice and wind A , σ B ; Among them, l oa and l ob are the horizontal distances from the lowest point of the transmission line to the suspension points A and B of the transmission line respectively; The S40 includes: S41: Substituting the three-dimensional spatial coordinates of the first line detection device and the second line detection device in the ice-free state into the sag formula to obtain the horizontal stress σ1 and the specific load γ1 of the transmission line in the ice-free state, and calculating the conductor load g2 of the transmission line in the ice-free state; g2=γ1*A S42: Calculate the vertical stress σ at the suspension points A and B of the transmission line in the presence of ice and no wind C , σ D ; S43: When When the transmission line is covered with ice and without wind, the ice load g1 is calculated by the formula g2=g+g1, and the ice load g1 is calculated by the formula g1=27.73δ(δ+d)×10 -3 Calculate the ice thickness δ1; Where d is the diameter of the transmission line.

2. The method for detecting ice coating on a power transmission line according to claim 1, wherein: The S50 includes: S51: Substituting the three-dimensional spatial coordinates of the first line detection device and the second line detection device in the icy and windy state into the sag formula to obtain the horizontal stress σ2 and the specific load γ2 of the transmission line in the icy and windy state, and calculating the conductor load g3 of the transmission line in the icy and windy state; g3=γ2*A S42: Calculate the vertical stress σ at the suspension points A and B of the transmission line under ice and wind conditions E , σ F ; S44: By formula Calculate the ice load g6 of the transmission line under the conditions of ice and wind, and use the formula g6=27.73δ(δ+d)×10 -3 Calculate the ice thickness δ2; Among them, g5=g+g6, g4=0.625v 2 daμ sc ×10 -3 , v is the wind speed, a is the wind pressure unevenness coefficient of the transmission line, μ sc is the wire shape coefficient of the transmission line.

3. The method for detecting ice coating on a power transmission line according to claim 2, wherein: The method further comprises: S60: Compare the horizontal stresses σ0, σ1, and σ2 of the transmission line in the ice-free and windless state, the ice-covered and windy state, and the ice-covered and windy state with the maximum tension F that the transmission line can withstand, and issue a warning signal when σ0, σ1, and σ2 exceed a first set percentage of the maximum tension F.

4. The method for detecting ice coating on a power transmission line according to claim 3, characterized in that: The method further comprises: S70: The vertical stress σ of the transmission line suspension points A and B in the ice-free and windless state, the ice-free and windy state, and the ice-windy state. A , σ B , σ C , σ D , σ E , σ F Compare them with the maximum pressure F1 that the insulator can withstand. A , σ B , σ C , σ D , σ E , σ F When the pressure exceeds the second set percentage of the maximum pressure F1, an early warning signal is issued.

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