Method for identifying typical microtopography and microclimate icing zones of power transmission line

Abstract

Disclosed in the present invention is a method for identifying typical microtopography and microclimate icing zones of a power transmission line, comprising: step 1, on the basis of the latitude and longitude of a tower, generating a DEM map covering an area of 1.5 km x 1.5 km centered on the longitude and latitude of the tower; step 2, filtering the DEM map; step 3, on the basis of the DEM map obtained in step 2, using a maximum slope gradient algorithm to extract typical topographic characteristic factors of icing zones; step 4, performing basic calculation on the basis of the topographic characteristic factors in step 3; and step 5, performing analysis on the basis of topographic characteristics, proposing quantitative values applicable to various microtopography and microclimate zones, and determining the presence of a mountain watershed, a terrain uplift, a saddle, a canyon wind corridor, and increased water vapor. The present invention solves the problem of identifying icing conditions in line sections having different types of microtopography and microclimates.

Description

A method for identifying typical micro-topography and microclimate icing zones along power transmission lines Technical Field

[0001] This invention belongs to the field of transmission line icing monitoring technology, and particularly relates to a method for identifying icing zones in typical micro-topography and microclimate of transmission lines. Background Technology

[0002] Icing on transmission lines has become a long-term threat to the safety of power grid operation. Icing-related accidents such as tower collapse, conductor breakage, and insulator string flashover occur frequently, leading to large-scale power outages and even system collapse, seriously affecting people's normal lives and causing extremely serious damage to the power system. To avoid ice disasters, monitoring of icing on transmission lines is of paramount importance.

[0003] Since the 1950s, researchers both domestically and internationally have conducted in-depth theoretical studies on transmission line icing, reaching systematic conclusions regarding its causes and principles. However, many scholars have gradually realized the significant impact of micro-topographical microclimates on transmission line icing and have attempted to analyze it by combining meteorological and topographical aspects. While many scholars have conducted research on the impact of specific meteorological or topographical factors, few have combined the influence of topography on meteorology to conduct research on topographic identification. Micro-topographical microclimate zones are mostly located in remote areas with underdeveloped transportation, resulting in limited field survey data. The definition and identification methods of micro-topographical microclimates remain poorly understood, and universally applicable research conclusions have not been derived through theoretical and quantitative analysis. Existing transmission line anti-icing designs rarely consider icing conditions within a 100-meter radius of micro-topographical microclimate zones; areas such as high mountains, mountain passes, and canyons remain design blind spots. Therefore, it is necessary to classify and identify these micro-topographical microclimate zones and conduct targeted research for each category.

[0004] Research on micro-topography and microclimate regional classification and identification methods helps to adopt reasonable anti-icing, anti-icing, and de-icing technologies, providing strong technical support for power grid icing prevention and disaster reduction, ensuring the safe operation of energy transmission channels, improving the power grid's ability to withstand disasters, and guaranteeing the electricity needs of the whole society. For long-distance transmission lines, especially ultra-high-voltage transmission lines, differentiated anti-icing designs can be implemented based on the icing conditions of different types of micro-topography and microclimate sections. This will effectively improve the reliability of power supply and the economic efficiency of power grid operation, and has important guiding significance for power grid de-icing and anti-icing work. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a method for identifying typical micro-topography and microclimate icing zones of transmission lines, so as to classify and identify micro-topography and microclimate zones 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 icing zones along power transmission lines, the method comprising:

[0008] Step 1: Generate a DEM map with a range of 1.5km × 1.5km centered on the pole's latitude and longitude.

[0009] Step 2: Filter the DEM image;

[0010] Step 3: Based on the DEM map obtained in Step 2, the maximum slope gradient algorithm is used to extract typical topographic feature factors of the icy area;

[0011] Step 4: Basic calculations were performed based on the terrain feature factors in Step 3;

[0012] Step 5: Based on the topographic features, conduct analysis and propose quantitative values ​​applicable to each micro-topography and microclimate region to determine whether there are high mountain watersheds, whether there is terrain uplift, whether there are mountain passes, whether there are canyon wind corridors, and whether there is an increase in water vapor.

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

[0014] Methods for filtering DEM maps include: using median filtering to fill in missing values ​​and improve the quality of DEM data.

[0015] Topographic feature factor extraction includes: slope and aspect extraction and slope variability and aspect variability extraction.

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

[0017] This paper proposes quantitative values ​​applicable to various micro-topographic and microclimate regions to determine the existence of high-mountain watersheds, terrain uplift, mountain passes, canyon wind corridors, and increased water vapor. The methods include: using quantitative parameters of characteristic quantities, such as: ① Elevation difference: calculating the elevation difference for four types of micro-topographic and microclimate regions: high-mountain watersheds, terrain uplift, mountain passes, and canyon wind corridors; ② Terrain uplift: calculating the slope ratio for these four types of micro-topography. Among them, only the maximum slope ratio is selected for terrain uplift; ③ Mountain pass: Based on the above calculation results, the mountain height of the mountain pass type is more than 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 above calculation results, the mountain height of the canyon wind tunnel 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 Increased water vapor: The tower of the water vapor increase type is less than 1000m away from the water body, and the width of the water body is more than 50m and the area is more than 1km².

[0018] The beneficial effects of this invention are:

[0019] This invention combines topographic elements used to describe landform types, uses median filtering to fill in missing values ​​in the original data and improve data quality, and selects appropriate algorithms to effectively extract the implicit topographic factors such as slope, aspect, curvature, variability, and topographic relief, as well as topographic feature lines such as valley lines and ridge lines, and topographic feature points such as mountain bottom points and mountain top points.

[0020] It solves the problem of identifying icing conditions on road sections with different micro-topography and microclimate.

[0021] Attached Figure Description

[0022] Figure 1 is a diagram showing the transformation between the original space and Hough space according to a specific embodiment of the present invention.

[0023] Detailed Implementation

[0024] A method for identifying typical micro-topographical and microclimate icing zones along power transmission lines, comprising:

[0025] Step 1: Based on the latitude and longitude of the towers, summarize the general trend of the transmission lines in each type of micro-topography and microclimate region. Based on geographic information data and basic definitions, determine the altitude of the tower location, the slope of the surrounding hillsides, the top and bottom of the hill, and water-related features as the basic reference features for classification and identification, and construct a matrix database. Generate a DEM map with a range of 1.5km × 1.5km centered on the latitude and longitude of the towers; the DEM map has functions such as topographic analysis, hydrological simulation, and land use planning.

[0026] Step 2: Based on the DEM map from Step 1, 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 varies with the complexity of the terrain; data point density refers to the minimum number of data points required to classify landform types; data point accuracy represents the unavoidable errors during data acquisition. Here, median filtering is used to fill in missing values ​​and improve the quality of the DEM data, filtering the original DEM map.

[0027] Step 3: Based on the processed DEM image obtained in Step 2, the maximum slope gradient algorithm is used to extract typical topographic feature factors of the icy area. ① Slope and Aspect Extraction: Among the topographic factors, slope and aspect are two parameters used to describe landform morphology, and they are interrelated. Slope reflects the tilt angle of the mountain, defined as the angle between the normal and the perpendicular line at a point P on the topographic surface, and the calculation range is limited to the cells in the surrounding eight directions. Aspect reflects the direction of the slope, defined as the angle between the positive direction of the normal at a point P in the plane projection and the geographic north direction. ② Slope Variation and Aspect Variation Extraction: Slope of Slope (SOS) is an indicator that measures the change in slope, while Slope of Aspect (SOA) is an indicator that measures the change in aspect. In practice, slope variation and aspect variation are related to the slope of the linear equation in analytic geometry. In this invention, the calculation of slope variability and aspect variability also adopts the maximum slope drop algorithm, that is, mathematical calculation is performed on the basis of the aforementioned slope and aspect extraction.

[0028] Step 4: Based on the basic calculations of terrain feature factors performed in Step 3, further analysis of terrain features is required. Hydrological analysis methods are generally applicable to large areas with distinct features. For the study area, a new feature line detection method, the Hough transform, 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, mainly involving the transformation of two spaces: the original space and the Hough space. In the original space, two points A(x, y) and B(x, y) can be connected by a straight line, with the equation y = kx + b. Transforming this to the Hough space converts it to expressions for k and b, as shown in Figure 1. In the original space, two points connected by a straight line become a single point in the Hough space. Multiple points in the original space are transformed into multiple straight lines in the Hough space. A point formed by as many straight lines as possible is selected, and the equation of the straight line in the original space is derived by detecting whether the cumulative number of points in the Hough space reaches a threshold.

[0029] Step 5: Based on topographic features, quantitative values ​​applicable to various micro-topographic and microclimate regions are proposed to determine the existence of high-mountain watersheds, terrain uplift, mountain passes, canyon wind corridors, and increased water vapor. The specific method uses the quantitative results of these characteristic quantities to make these judgments. These quantitative results include: ① Elevation difference: Calculating the elevation difference for the four types of micro-topographic and microclimate regions: high-mountain watersheds, terrain uplift, mountain passes, and canyon wind corridors. ② Terrain uplift: Calculating the slope ratio for the four types of micro-topography: high-mountain watersheds, terrain uplift, mountain passes, and canyon wind corridors. For terrain uplift, only the larger slope ratio on one side is selected. ③ Mountain pass: Based on the calculation results of the above sample cases, the mountain height of a mountain pass is generally above 150m, the elevation difference is greater than 121m, the horizontal distance between the highest and lowest points is not less than 150m, and the slope ratios |tanα| and |tanβ| are greater than 37%. ④ Canyon Wind Channel: Based on the calculation results of the above sample cases, the height of a canyon wind channel type mountain is generally over 100m, the elevation difference is greater than 81m, the horizontal distance between the highest and lowest points is not less than 150m, and the slope ratios |tanα| and |tanβ| are greater than 44%. ⑤ Increased Water Vapor: In most actual cases, the water systems, such as rivers and lakes, are large bodies of water, with river widths greater than 100m and water areas greater than 500 km². Based on the calculation results of the above sample cases, the towers of large water vapor-increasing structures are less than 1000m from the water body, and the water body is more than 50m wide and has an area greater than 1 km².

Claims

1. A method for identifying icing zones in typical micro-topography and microclimate of transmission lines, characterized in that: The method includes: Step 1: Generate a DEM map with a range of 1.5km × 1.5km centered on the pole's latitude and longitude. Step 2: Filter the DEM image; Step 3: Based on the DEM map obtained in Step 2, the maximum slope gradient algorithm is used to extract typical topographic feature factors of the icy area; Step 4: Basic calculations were performed based on the terrain feature factors in Step 3; Step 5: Based on the topographic features, conduct analysis and propose quantitative values ​​applicable to each micro-topography and microclimate region to determine whether there are high mountain watersheds, whether there is terrain uplift, whether there are mountain passes, whether there are canyon wind corridors, and whether there is an increase in water vapor.

2. The method for identifying typical micro-topography and microclimate icing zones of transmission lines according to claim 1, characterized in that: The method for generating a DEM map with a range of 1.5km × 1.5km centered on the latitude and longitude of the tower includes: based on geographic information data and basic definitions, determining the altitude of the tower location, the slope of the two sides of the mountain, the top of the mountain, the bottom of the mountain, and the water-related features as the basic reference features for classification and identification, constructing a matrix database, and generating a DEM map with a range of 1.5km × 1.5km centered on the latitude and longitude of the tower.

3. The method for identifying typical micro-topography and microclimate icing zones of transmission lines according to claim 1, characterized in that: Methods for filtering DEM maps include: using median filtering to fill in missing values ​​and improve the quality of DEM data.

4. The method for identifying typical micro-topography and microclimate icing zones of transmission lines according to claim 1, characterized in that: Topographic feature factor extraction includes: slope and aspect extraction and slope variability and aspect variability extraction.

5. The method for identifying typical micro-topography and microclimate icing zones of transmission lines according to claim 1, characterized in that: The Hough transform method was used to analyze the terrain features.

6. The method for identifying typical micro-topography and microclimate icing zones of transmission lines according to claim 1, characterized in that: This paper proposes quantitative values ​​applicable to various micro-topographic and microclimate regions to determine the existence of high-mountain watersheds, terrain uplift, mountain passes, canyon wind corridors, and increased water vapor. The methods include: using quantitative parameters of characteristic quantities, such as: ① Elevation difference: calculating the elevation difference for four types of micro-topographic and microclimate regions: high-mountain watersheds, terrain uplift, mountain passes, and canyon wind corridors; ② Terrain uplift: calculating the slope ratio for these four types of micro-topography. Among them, only the maximum slope ratio is selected for terrain uplift; ③ Mountain pass: Based on the above calculation results, the mountain height of the mountain pass type is more than 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 above calculation results, the mountain height of the canyon wind tunnel 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 Increased water vapor: The tower of the water vapor increase type is less than 1000m away from the water body, and the width of the water body is more than 50m and the area is more than 1km².

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