Typical microtopography and microclimate icing area identification method for power transmission line

Abstract

The invention discloses a power transmission line typical microtopography microclimate icing area identification method, which comprises the following steps: step 1, generating a DEM graph in a 1.5 km * 1.5 km range by taking the latitude and longitude of a tower as a center according to the latitude and longitude of the tower; step 2, carrying out filtering processing on the DEM graph; 3, based on the DEM graph obtained in the step 2, a maximum gradient algorithm is adopted to extract typical topographic feature factors of the icing area; 4, carrying out basic measurement calculation based on the topographic feature factors in the step 3; 5, analysis is carried out based on topographic features, quantitative numerical values suitable for all micro-topographic microclimate areas are provided, and whether a high mountain watershed exists, whether topographic uplift exists, whether a bealock exists, whether a canyon air duct exists and whether water vapor increase exists are judged; the problem of identifying icing conditions of different types of microtopography and microclimate road sections is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of transmission line icing monitoring, and in particular relates to a method for identifying typical micro-topography and microclimate icing areas of transmission lines. Background Art

[0002] Icing on transmission lines has become a long-term safety issue threatening the operation of power grids. Ice disasters such as tower collapse, conductor breakage, and insulator flashover occur frequently, leading to large-scale power outages and even system breakdown, seriously affecting people's normal lives and causing extremely serious damage to the power system. In order to avoid ice disasters, it is crucial to monitor the icing on transmission lines.

[0003] Since the 1950s, researchers at home and abroad have conducted in-depth theoretical research on transmission line icing, and have systematically concluded its causes and principles. However, many scholars have gradually realized that the impact of micro-topography and microclimate areas on transmission line icing cannot be ignored, and have tried to analyze it in combination with meteorology and topography. Many scholars have conducted research on the impact of a specific meteorological factor or topographic factor, but few have conducted research on terrain identification in combination with the impact of terrain on meteorology. Micro-topography and microclimate areas are mostly located in remote areas with underdeveloped transportation, and there are few field survey data. People still lack knowledge of the definition and identification methods of micro-topography and microclimate, and no universal research conclusions have been drawn through theoretical and quantitative analysis. The existing anti-icing design of transmission lines rarely considers the icing of lines in micro-topography and microclimate areas within a hundred meters. Micro-topography and microclimate areas such as mountains, passes, and canyons are still in the design blind spot. Therefore, it is necessary to classify and identify these micro-topography and microclimate areas, and conduct targeted research on each type of area.

[0004] The research on the classification and identification method of micro-topography and microclimate regions is helpful to take reasonable technical measures such as anti-icing, ice prevention, and ice melting, providing strong technical support for the anti-icing and disaster reduction work of the power grid, ensuring the safe operation of the energy delivery channel, improving the ability of the power grid to resist disasters, and guaranteeing the electricity demand of the whole society. For long-distance transmission lines, especially ultra-high voltage transmission lines, differentiated anti-icing designs can be carried out according to the icing conditions of different types of micro-topography and microclimate sections, which will effectively improve the power supply reliability and economic benefits of the power grid, and have important guiding significance for the de-icing and anti-icing work of the power grid. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to provide a method for identifying typical micro-topography and microclimate ice-covered areas of transmission lines, so as to classify and identify micro-topography and microclimate areas, and provide differentiated anti-icing design suggestions for long-distance transmission lines, especially ultra-high voltage transmission lines.

[0006] Technical solution of the present invention:

[0007] A method for identifying typical micro-topography and microclimate ice-covered areas of a power transmission line, the method comprising:

[0008] Step 1: Generate a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower according to the longitude and latitude of the tower;

[0009] Step 2: Filter the DEM image;

[0010] Step 3: Based on the DEM map obtained in step 2, the maximum slope drop algorithm is used to extract the typical terrain characteristic factors of the ice-covered area;

[0011] Step 4: Perform basic calculations based on the terrain characteristic factors in step 3;

[0012] Step 5: Analyze the terrain characteristics and propose quantitative values ​​applicable to each micro-topography and microclimate zone to determine whether there is a high mountain watershed, whether there is terrain uplift, whether there is a pass, whether there is a canyon wind channel, and whether there is increased water vapor.

[0013] The method for generating a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower includes: based on geographic information data and basic definitions, determining the altitude of the location of the tower, the inclination of the hillsides on both sides, the top of the mountain, the bottom of the mountain and the water body related characteristics as basic reference feature quantities for classification and identification, constructing a matrix database, and generating a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower.

[0014] The methods for filtering DEM images include: filling missing values ​​and improving the quality of DEM data through median filtering.

[0015] The extraction of terrain characteristic factors includes: slope and aspect extraction and slope variability and aspect variability extraction.

[0016] The Hough transform method is used to analyze terrain features.

[0017] The quantitative numerical values ​​applicable to each micro-topography microclimate area are proposed. The method for judging whether there is a high mountain watershed, whether there is terrain uplift, whether there is a pass, whether there is a canyon wind channel and whether there is water vapor increase includes: judging by the quantitative result parameters of the characteristic quantity, and the quantitative result parameters of the characteristic quantity include: ① elevation difference: calculating the elevation difference of four types of micro-topography microclimate areas, namely, high mountain watershed, terrain uplift, pass and canyon wind channel; ② terrain uplift: calculating the slope ratio of four types of micro-topography, namely, high mountain watershed, terrain uplift, pass and canyon wind channel, among which only the largest slope ratio value is selected for terrain uplift; ③ pass: based on the above calculation, the elevation difference of the four types of micro-topography is calculated. 4. Canyon wind channel: Based on the above calculation results, the mountain height of the canyon wind channel type is more than 100m, the elevation difference is greater than 81m, the horizontal distance between the highest point and the lowest point is not less than 150m, and the mountain slope ratio |tanα| and |tanβ| are greater than 44%; 5. Water vapor increase: The tower of the water vapor increase type is less than 1000m away from the water body, and the water body width is more than 50m and the area is 1km 2 above.

[0018] Beneficial effects of the present invention:

[0019] The present invention combines the terrain elements used to describe the landform type, uses the median filtering method to fill in the missing values ​​in the original data and improve the data quality, and selects a suitable algorithm to effectively extract the implicit terrain factors such as slope, aspect, curvature, variability, terrain undulation, terrain feature lines such as valley lines and ridge lines, and terrain feature points such as mountain bottom points and mountain top points.

[0020] The problem of identifying icing conditions on road sections with different types of micro-topography and microclimates has been solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a conversion diagram between the original space and the Hough space according to a specific implementation manner of the present invention. DETAILED DESCRIPTION

[0022] A method for identifying typical micro-topography and microclimate ice-covered areas of a transmission line, comprising:

[0023] Step 1: According to the longitude and latitude of the tower, summarize the general trend of the transmission line in each type of micro-topography and microclimate area. Based on geographic information data and basic definitions, determine the altitude of the tower location, the slope of the hillsides on both sides, the top of the mountain, the bottom of the mountain, and the water body related characteristics as the basic reference feature quantity for classification and identification, and build a matrix database. Generate a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower; the DEM map has the functions of terrain analysis, hydrological simulation, land use planning, etc.

[0024] Step 2: Based on the DEM map in step 1, in order to improve the accuracy and smoothness of the data and to further analyze the terrain, the original data needs to be processed. The distribution of data points changes with the complexity of the terrain; the density of data points refers to the minimum number of data points required to classify landform types; the accuracy of data points refers to the inevitable errors when obtaining data. Here, the median filter method is used to fill in missing values ​​and improve the quality of DEM data, and the original DEM map is filtered;

[0025] Step 3. Based on the processed DEM map obtained in step 2, the maximum slope algorithm is used to extract the typical terrain characteristic factors of the ice-covered area. ① Slope and aspect extraction: Slope and aspect are two parameters used to describe the landform in terrain factors, and the two are related to each other. The slope reflects the inclination angle of the mountain, which is defined as the angle between the normal and the vertical line of a point P on the terrain surface, and the calculation range is limited to the cells in the eight directions around. The aspect reflects the direction corresponding to the slope, which is defined as the angle between the positive direction of the normal of a point P on the plane projection and the geographic north direction. ② Slope variability and aspect variability extraction: Slope of Slope (SOS) is an indicator for measuring the change of slope, and Slope of Aspect (SOA) is an indicator for measuring the change of aspect. In practice, the slope variability is related to the aspect variability and the slope of the straight line equation in analytic geometry. In the present invention, the maximum slope drop algorithm is also used to calculate the slope change rate and the slope aspect change rate, that is, mathematical calculations are continued on the basis of the above-mentioned slope and aspect extraction.

[0026] Step 4. Based on the basic calculation of terrain feature factors in step 3, the terrain features need to be analyzed. Hydrological analysis methods are mostly suitable for areas with large ranges and obvious features. For the study area, a new feature line detection method, namely the Hough transform method, is proposed. The Hough transform detection method relies on image processing and is used for image shape detection. It has good noise resistance and low detection difficulty. It mainly involves the conversion of two spaces, namely the original space and the Hough space. In the original space, two points A (x, y) and B (x, y) can be connected into a straight line, and the equation of the line is y = kx + b. Converting it to the Hough space can be converted into expressions of k and b. The space conversion is shown in the attached figure. Figure 1 As shown. In the original space, two points are connected by a straight line, which will become a point when converted to Hough space. Convert multiple points in the original space into multiple straight lines in Hough space, select points formed by as many straight lines as possible, and deduce the straight line equation in the original space by detecting whether the cumulative amount of points in Hough space reaches the threshold.

[0027] Step 5: Based on the terrain characteristics, quantitative values ​​suitable for each micro-topography microclimate area are proposed to determine whether there is a high mountain watershed, whether there is terrain uplift, whether there is a pass, whether there is a canyon wind channel, and whether there is water vapor increase. The specific method is to judge through the quantitative result parameters of the characteristic quantity. The quantitative result parameters of the characteristic quantity include: ① Elevation difference: calculate the elevation difference of four types of micro-topography microclimate areas, namely, high mountain watershed, terrain uplift, pass, and canyon wind channel. ② Terrain uplift: calculate the slope ratio of four types of micro-topography, namely, high mountain watershed, terrain uplift, pass, and canyon wind channel, among which terrain uplift only selects the larger slope ratio value on one side. ③ Pass: Based on the calculation results of the above sample cases, the height of the pass-type mountain is generally above 150m, the elevation difference is greater than 121m, the horizontal distance between the highest point and the lowest point is not less than 150m, and the mountain slope ratio |tanα| and |tanβ| are greater than 37%. ④ Canyon wind tunnel: Based on the calculation results of the above sample cases, the mountain height of the canyon wind tunnel type is generally above 100m, the elevation difference is greater than 81m, the horizontal distance between the highest point and the lowest point is not less than 150m, and the mountain slope ratio |tanα| and |tanβ| are greater than 44%. ⑤ Water vapor increase: In most actual cases, the water systems, such as rivers and lakes, are large water bodies, with river widths greater than 100m and water areas greater than 500km 2 Based on the calculation results of the above sample cases, the distance between the tower and the water body is less than 1000m, and the width of the water body is more than 50m and the area is 1km 2 above.

Claims

1. A method for identifying typical micro-topography and microclimate ice-covered areas of power transmission lines, characterized by: The method comprises: Step 1: Generate a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower according to the longitude and latitude of the tower; Step 2: Filter the DEM image; Step 3: Based on the DEM map obtained in step 2, the maximum slope drop algorithm is used to extract the typical terrain characteristic factors of the ice-covered area; Step 4: Perform basic calculations based on the terrain characteristic factors in step 3; Step 5: Analyze the terrain characteristics and propose quantitative values ​​applicable to each micro-topography and microclimate zone to determine whether there is a high mountain watershed, whether there is terrain uplift, whether there is a pass, whether there is a canyon wind channel, and whether there is increased water vapor.

2. The method for identifying typical micro-topography and microclimate icing areas of a power transmission line according to claim 1 is characterized by: The method for generating a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower includes: based on geographic information data and basic definitions, determining the altitude of the location of the tower, the inclination of the hillsides on both sides, the top of the mountain, the bottom of the mountain and the water body related characteristics as basic reference feature quantities for classification and identification, constructing a matrix database, and generating a DEM map with a range of 1.5km×1.5km centered on the longitude and latitude of the tower.

3. The method for identifying typical micro-topography and microclimate icing areas of a power transmission line according to claim 1 is characterized by: The methods for filtering DEM images include: filling missing values ​​and improving the quality of DEM data through median filtering.

4. The method for identifying typical micro-topography and microclimate icing areas of a power transmission line according to claim 1, characterized in that: The extraction of terrain characteristic factors includes: slope and aspect extraction and slope variability and aspect variability extraction.

5. The method for identifying typical micro-topography and microclimate icing areas of a power transmission line according to claim 1 is characterized by: The Hough transform method is used to analyze terrain features.

6. The method for identifying typical micro-topography and microclimate icing areas of a power transmission line according to claim 1, characterized in that: The quantitative numerical values ​​applicable to each micro-topography microclimate area are proposed. The method for judging whether there is a high mountain watershed, whether there is terrain uplift, whether there is a pass, whether there is a canyon wind channel and whether there is water vapor increase includes: judging by the quantitative result parameters of the characteristic quantity, and the quantitative result parameters of the characteristic quantity include: ① elevation difference: calculating the elevation difference of four types of micro-topography microclimate areas, namely, high mountain watershed, terrain uplift, pass and canyon wind channel; ② terrain uplift: calculating the slope ratio of four types of micro-topography, namely, high mountain watershed, terrain uplift, pass and canyon wind channel, among which only the largest slope ratio value is selected for terrain uplift; ③ pass: based on the above calculation, the elevation difference of the four types of micro-topography is calculated.

4. Canyon wind channel: Based on the above calculation results, the mountain height of the canyon wind channel type is more than 100m, the elevation difference is greater than 81m, the horizontal distance between the highest point and the lowest point is not less than 150m, and the mountain slope ratio |tanα| and |tanβ| are greater than 44%; 5. Water vapor increase: The tower of the water vapor increase type is less than 1000m away from the water body, and the water body width is more than 50m and the area is 1km 2 above.

Images