Micro-terrain axis and wind direction coupled transmission line section evaluation method and system

Abstract

This invention discloses a segmented assessment method for transmission lines based on the coupling of micro-topographic axis and wind direction. The method includes the following steps: segmenting the transmission line and calculating the axial azimuth of each segment; determining the axial azimuth of the micro-topographic axis, obtaining the prevailing wind direction angle at the location of the micro-topographic axis, and calculating the minimum axial angle between the two; calculating the normal relative elevation difference index of the micro-topographic axis; calculating the spatial relationship between each transmission line segment and the micro-topographic axis; and coupling the minimum axial angle, normal relative elevation difference index, and spatial relationship between each transmission line segment and the micro-topographic axis to construct a multi-dimensional risk profile of the transmission line segment. This application enables refined analysis of different line segments, avoids the problem of spatial information averaging caused by overall analysis, and thus significantly improves the spatial accuracy of transmission line assessment in complex terrain areas.

Description

Technical Field

[0001] This invention relates to the fields of Geographic Information Systems (GIS), digital terrain analysis, power line engineering assessment and spatial data processing. More specifically, this invention relates to a method and system for segmented assessment of power transmission lines coupled with micro-topographic axes and wind direction. Background Technology

[0002] When transmission lines operate in mountainous areas and regions with complex micro-topography, the spatial relationship between the line alignment and topographical structures such as ridges and valleys, as well as the prevailing wind direction, significantly affects the local wind field distribution and disaster risk. Therefore, in the selection and operation assessment of transmission lines, it is usually necessary to combine digital elevation models (DEM), wind direction raster data, and line spatial data to analyze the relationship between the line and the micro-topography.

[0003] In existing technologies, the relationship between transmission lines and micro-topography such as ridges and valleys largely relies on manual experience or simple spatial overlay analysis. This typically only determines whether the line intersects with topographical features, lacking a comprehensive quantitative analysis method for topographic structure, wind direction relationships, and the degree of topographic undulation at the line segment scale. Furthermore, because ridge or valley axes are usually represented using a directionless axis, and wind direction data uses 0... 360 The directional angle representation lacks a unified comparison method, which can easily lead to unstable angle analysis results. In addition, traditional methods also lack a mechanism for systematic profile analysis along the normal direction of the micro-topographic axis, making it difficult to fully reflect the topographic undulation characteristics on both sides of the ridge or canyon.

[0004] Therefore, it is necessary to propose a method that can combine transmission line segmentation, micro-topographic axis and wind direction field information for coupled analysis in order to achieve quantitative and structured evaluation of transmission lines in complex terrain areas.

[0005] When transmission lines operate in mountainous areas and regions with complex micro-topography, the spatial relationship between the line alignment and topographical structures such as ridges and valleys, as well as the prevailing wind direction, significantly affects the local wind field distribution and disaster risk. Therefore, in the selection and operation assessment of transmission lines, it is usually necessary to combine digital elevation models (DEM), wind direction raster data, and line spatial data to analyze the relationship between the line and the micro-topography.

[0006] Existing technologies typically analyze the entire route or typical local points, making it difficult to characterize the differences in the relationship between different route sections and micro-topography and wind direction. Existing methods do not uniformly handle the differences between directional axis angles and directional wind direction angles, leading to unstable angle determination results. Existing technologies cannot fully reflect the spatial non-uniformity of topographic relief on both sides of ridges or canyons. Existing technologies often use simple spatial intersection relationships to determine whether a route crosses a ridge or canyon, without fully considering situations where the route and axis are closely aligned, cross at close range, or are spatially very close but not strictly intersecting, which can easily lead to missed judgments and affect the reliability of engineering analysis results.

[0007] Therefore, it is necessary to propose a method that can combine transmission line segmentation, micro-topographic axis, and wind direction field information for coupled analysis. This method can achieve quantitative and structured evaluation of transmission lines in complex terrain areas by segmenting and evaluating transmission lines, unifying the angle comparison system between the axis and wind direction, conducting relative elevation difference analysis along the axis normal, and establishing a robust crossing judgment mechanism. Summary of the Invention

[0008] To overcome the aforementioned deficiencies in existing technologies, this patent proposes a method and system for segmented evaluation of transmission lines that couples micro-topographic axes with wind direction. By extracting the micro-topographic axis, unifying the calculation method of the angle between the axis and the wind direction, and combining it with the analysis of the relative height difference along the axis normal, the method achieves quantitative identification and segmented evaluation of transmission lines crossing ridges and canyons.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction, characterized by the following steps: The transmission line is divided into segments, and the axial azimuth angle of each segment is calculated. Determine the azimuth angle of the micro-topography axis and the prevailing wind direction angle at its location, and then calculate the minimum axial angle between the two after converting them to a unified angle measurement system. Calculate the normal relative elevation difference index of the micro-topographic axis; Calculate the spatial relationship between each transmission line segment and the micro-topographic axis, and determine whether the transmission line segment crosses the micro-topographic axis based on the spatial relationship; The minimum axial angle, the normal relative elevation difference index, and the determination result of whether the transmission line segment crosses the micro-topographic axis are coupled together to construct a multi-dimensional risk profile of the transmission line segment.

[0010] In a preferred embodiment, the entire transmission line is divided into multiple continuous transmission line segments by directly generating the original line node structure or by subdividing it according to a preset length. The axial azimuth angle of each transmission line segment is determined by the coordinates of the beginning and end points of the segment and mapped to an axial angle range of 0° to 180°.

[0011] In a preferred embodiment, the micro-topography axis extraction method includes the following steps: Construct a binary mask grid for micro-topography; Morphological closing operations are performed on the mask to fill holes and enhance connectivity; The processed mask is then subjected to skeletonization to obtain a skeleton structure with a single pixel width. Continuous paths are traced based on the spatial adjacency relationships of skeleton pixels, and vectorized to generate micro-topographic axes.

[0012] In a preferred embodiment, the azimuth angle of the micro-topography axis is θ. r ,and:

[0013]

[0014] Where (x1, y1) are the starting coordinates of the micro-topography axis, (x2, y2) are the ending coordinates of the micro-topography axis, and atan2 is the two-parameter arctangent function.

[0015] In a preferred embodiment, when obtaining the prevailing wind direction angle at the location of the micro-topography axis, the wind direction value is read from the wind direction grid data by sampling at the center point of the axis or by averaging multiple sampling points along the axis.

[0016] In a preferred embodiment, the prevailing wind direction angle and the axial azimuth angle of the micro-topography axis are converted to the same angle measurement system, namely:

[0017] in: This indicates the converted axial wind direction angle. This indicates the axial wind direction angle before the conversion.

[0018] In a preferred embodiment, the minimum axial included angle Δ is:

[0019] Where: θ r Let θ′ be the azimuth angle of the micro-topographic axis. w The unified wind direction angle, Δ, has a range of 0. 90 .

[0020] In a preferred embodiment, calculating the normal relative elevation difference index of the micro-topographic axis includes the following steps: Along the micro-topography axis, center points of the directional profile are arranged at preset intervals, and a normal profile line orthogonal to the axis direction is constructed at each center point; The elevation of the normal profile line is sampled using a digital elevation model to obtain the elevation sequence of the profile. Calculate the elevation difference between the center point of each profile and the lowest points on both sides, and take the larger of the elevation differences on both sides as the relative elevation difference of the profile. Statistical calculations are performed on the relative height differences of all profiles along the axis to obtain a set of statistical indicators describing the intensity of micro-topographic undulations. These statistical indicators include, but are not limited to, the maximum value, average value, and percentile value of the relative height differences.

[0021] In a preferred embodiment, when determining whether a transmission line segment crosses a micro-topographic axis, if the transmission line segment and the micro-topographic axis have geometric intersection, spatial overlap, or a minimum spatial distance less than or equal to a preset threshold, then the transmission line segment is determined to cross the micro-topographic axis.

[0022] A segmented evaluation system for transmission lines coupled with micro-topographic axes and wind direction includes: The processing module is used to execute the transmission line segment evaluation method based on the coupling of micro-topographic axis and wind direction as described in any one of claims 1 to 9.

[0023] The technical effects and advantages of this invention are as follows: 1. This application divides the entire transmission line into multiple independent line segments and uses each line segment as the smallest unit of analysis to analyze the spatial relationship between the segment and the ridge or canyon axis, as well as the corresponding wind direction and terrain features. This enables refined analysis of different line segments, avoids the problem of spatial information averaging caused by overall analysis, and thus significantly improves the spatial accuracy of transmission line evaluation in complex terrain areas.

[0024] 2. This application achieves this by setting the micro-topographic axis to 0... 180 Axial angle system and wind direction grid 0 360 The wind direction angle system is uniformly converted, and a formula for calculating the minimum axial angle is constructed to achieve stable quantification of the relationship between the axial direction and the prevailing wind direction. This can eliminate errors caused by differences in the angle system and make the relationship between wind direction and terrain structure more stable and consistent.

[0025] 3. This application incorporates the intersection, overlap and proximity relationships between the line segment and the micro-topographic axis into the crossing judgment framework, and combines the axis-wind direction angle index and the relative height difference index calculated along the axis normal to construct a micro-topographic coupling risk profile at the line segment level. This can more comprehensively reflect the topographic structure and wind field conditions when the line crosses a ridge or canyon, thus providing a more reliable quantitative basis for the analysis of transmission line icing risk and route selection optimization. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process for evaluating the segmented transmission line based on the coupling of micro-topography axis and wind direction according to the present invention.

[0027] Figure 2 This is a schematic diagram illustrating the smoothing and connectivity enhancement of mask data using morphological closing operations in this embodiment.

[0028] Figure 3 , Figure 4 This is a schematic diagram of the skeletonization calculation results for the canyon area in this embodiment.

[0029] Figure 5 This is a schematic diagram of the transmission line segment crossing the mountain ridge in this embodiment.

[0030] Figure 6 This is a schematic diagram of the transmission line segment crossing the canyon in this embodiment. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, this application presents a segmented evaluation method for transmission lines coupled with micro-topographic axes and wind direction. The basic input data includes transmission line vector data, Digital Elevation Model (DEM) raster data, wind direction raster data, and micro-topographic axis data such as ridges and canyons. Specifically, the transmission line data describes the spatial location and orientation of the line under evaluation, the DEM data reflects surface elevation characteristics, the wind direction raster data provides information on the prevailing wind direction in the region, and the micro-topographic axis data characterizes the spatial location and directional attributes of linear topographic units such as ridges and canyons.

[0033] The evaluation method includes the following steps: The transmission line is divided into segments, and the axial azimuth angle of each segment is calculated. Specifically, in order to achieve a refined assessment of different sections of the transmission line, this application divides the entire transmission line into multiple continuous transmission line segments, and uses each segment as an independent assessment unit.

[0034] Let the k-th line segment be denoted as L. k Then the entire transmission line can be represented as: ; Where n represents the total number of route segments. Each route segment can be generated directly based on the original route node structure, or it can be further subdivided according to a preset length. This segmentation method can avoid the spatial averaging effect caused by the overall analysis of the entire route, and enable each route segment to establish a correspondence with its neighboring ridges, valleys and wind direction information, thereby improving the spatial resolution of subsequent evaluation results.

[0035] After the line segment is constructed, it is necessary to calculate the axial azimuth of each line segment to describe the dominant spatial orientation of the line segment.

[0036] Let the starting point coordinates of a certain line segment be (x1, y1) and the ending point coordinates be (x2, y2), then its planar increment is:

[0037] Based on the aforementioned direction vectors, the azimuth angle of the line segment relative to true north can be calculated:

[0038] Where θ line The axial azimuth of the transmission line segment is represented by atan2, a two-parameter arctangent function used to determine the quadrant in which the direction vector lies. Since the transmission line segment is represented axially without direction in subsequent analysis, it can be further mapped to 0. 180 The range of axial angles.

[0039] Therefore, the axial azimuth angle of the line segment is defined as:

[0040] Where, θ line It only indicates the direction of the axis where the line segment is located, without distinguishing between the starting direction and the reverse direction. In the specific implementation, this axial azimuth angle can be recorded as the line segment attribute field th_line and used as an important input parameter for subsequent calculation of the minimum axial angle.

[0041] For a line segment consisting of multiple inflection points, the axial orientation can be determined primarily by the first and last points of the line segment. If it is necessary to improve directional stability, the overall principal axis direction of the line segment can also be estimated. Through the above steps, this application has completed the construction of the transmission line segment unit and established geometric information and directional attributes for each line segment, providing basic data support for subsequent micro-topographic axis extraction, wind direction coupling analysis, normal relative height difference calculation, and line crossing determination.

[0042] Determine the azimuth angle of the micro-topography axis, obtain the prevailing wind direction angle at the location of the micro-topography axis, and calculate the minimum axial angle between the two.

[0043] In this application, the micro-topographic axis data can be derived from existing manually extracted vector data or automatically generated based on digital elevation models or micro-topographic mask grids.

[0044] When ridge or canyon axis data already exists in the study area, it can be directly read and used for subsequent analysis; when existing axis data is lacking, the corresponding micro-topographic axis structure can be generated through automatic extraction methods. The extraction method includes the following steps: First, a binary mask grid needs to be constructed for the ridges or canyons. Let the micro-topography mask be:

[0045] Where M(x,y) represents the mask value at grid position (x,y), Ω m This represents the target micro-topography region. When M(x,y)=1, it indicates that the pixel belongs to the target micro-topography region.

[0046] Morphological closing operations are performed on the mask to fill holes and enhance smooth connectivity; Because the original mask data may contain local noise, small-scale holes, or regional breaks, this patent performs morphological processing on the mask data before skeleton extraction to improve the stability of the axis extraction results. Morphological closing operations are used to smooth the mask and enhance its connectivity.

[0047] Where B is a structuring element, and ⊕ represents the expansion operation. This represents the erosion operation. This process can fill small voids in the mask and enhance regional connectivity, thereby reducing breakage during skeleton extraction.

[0048] The processed mask is then subjected to skeletonization to obtain a skeleton structure with a single pixel width. After the mask M is processed cThen, it is processed into a skeleton, compressing the originally variable-width micro-topographic region into a skeleton structure with a single pixel width:

[0049] Among them, Skel ( ) represents the morphological skeleton operator, and S represents the micro-topographic skeleton set. This set can reflect the central structure of the micro-topographic region and is an important foundation for constructing micro-topographic axes.

[0050] After obtaining the skeleton raster, it is necessary to identify the connected structure based on the spatial adjacency relationships between skeleton cells, and then gradually trace along the connection directions of the skeleton cells to form a continuous path. Let a certain skeleton path be:

[0051] Where p i This represents the coordinates of the skeleton pixels. Using the transformation relationship between raster coordinates and spatial coordinates, the skeleton path can be converted into a polyline structure in actual spatial coordinates, thus obtaining the i-th micro-topographic axis:

[0052] Where R i This represents the i-th micro-topographic axis.

[0053] The generated axes are filtered by length, and noisy line segments with a length less than a preset threshold are removed.

[0054] During skeleton extraction, short or fragmented line segments may be generated. To improve the continuity and stability of the axis structure, this patent further processes the generated axes. First, a geometric simplification algorithm is used to reduce redundant nodes in the polylines, making the axes smoother; then, the axes are filtered according to a preset minimum length threshold. When the length of an axis is less than the threshold, it is considered a noise structure and is discarded. The axis length can be expressed as:

[0055] In addition, axes that are spatially adjacent and oriented in the same direction can be merged to obtain a more continuous and stable ridge or canyon axis structure.

[0056] After obtaining the final micro-topographic axes, it is necessary to calculate the dominant spatial direction, i.e., the azimuth angle, for each axis. Let the coordinates of the start and end points of a given axis be (x1, y1) and (x2, y2) respectively, then its direction increment in the plane coordinate system is:

[0057] Based on the aforementioned directional increments, the azimuth angle of the axis relative to true north can be calculated:

[0058] Where θ r This represents the direction angle of the micro-topographic axis in the plane coordinate system. Here, atan2 is a two-parameter arctangent function used to determine the quadrant in which the direction vector lies. Since ridge or canyon axes are directionless linear structures, their positive and negative directions are geometrically equivalent. Therefore, in subsequent analysis, only the overall directional characteristics of the axis need to be considered, without distinguishing between positive and negative directions. When calculating the relationship between micro-topographic axes and wind direction, data from different directions can be converted using a unified angle system, thereby ensuring the consistency and stability of angle calculations.

[0059] Through the above steps, a micro-topographic axis dataset containing geometric structure, axis length, and directional attributes can be obtained. This dataset not only describes the spatial location and extension direction of ridges or valleys, but also provides basic data support for subsequent calculations of the angle between micro-topographic axes and wind direction, as well as for determining power transmission line crossings.

[0060] After obtaining the micro-topographic axes and their azimuths, it is necessary to further analyze the spatial relationship between the micro-topographic structure and the regional wind field. Since the directional characteristics of ridge or canyon axes affect the flow and distribution of local wind fields, the coupling relationship between topographic structure and wind field can be quantitatively characterized by calculating the angle between the direction of the micro-topographic axis and the prevailing wind direction.

[0061] This patent obtains the minimum axial angle index between the micro-topographic axis and the wind direction by reading wind direction grid data of the study area and combining it with the spatial location of the micro-topographic axis. This provides basic data for the subsequent evaluation of transmission lines crossing micro-topographic sections.

[0062] Wind direction grid sampling typically provides wind direction information in the form of grid data, where each grid cell records the wind direction angle at that location. Let the wind direction grid of the study area be W(x,y), where (x,y) represents the grid position and the corresponding wind direction angle is denoted as θ. w Wind direction angle is usually taken as 0. 360 The angle system indicates the direction from which the wind is coming.

[0063] In practical calculations, it is necessary to spatially overlay the micro-topography axis with the wind direction grid to obtain the wind direction value at the axis location. This patent can employ the following two sampling methods: 1. Center point sampling method: The geometric center point of the micro-topography axis is used as the sampling position, and the wind direction value at the corresponding position is read from the wind direction grid.

[0064] 2. Multi-point sampling method: Multiple sampling points are set up at certain intervals along the micro-topography axis, and the corresponding wind direction values ​​are read from the wind direction grid. The wind direction values ​​representing the wind direction characteristics of the axis area are obtained by statistical averaging and other methods.

[0065] Using the sampling method described above, the corresponding wind direction angle θ can be obtained for each micro-topographic axis. w .

[0066] The axis azimuth and wind direction angle systems must be unified. Before calculating the included angle, the axis direction and wind direction angle systems need to be unified. Micro-topography axis azimuth angle θ r Use 0 360 The azimuth angle is used, and the wind direction data also uses 0. 360 The angle system is similar, but since the ridge or canyon axis is a non-directional linear structure, its positive and negative directions are geometrically equivalent. Therefore, in subsequent analysis, we only need to focus on the axial characteristics of the axis without distinguishing between positive and negative directions.

[0067] To ensure consistency in angle comparisons, wind direction angles can be converted into an axial angle system that is the same as the axis direction, i.e.:

[0068] Where θ′ w This represents the converted axial wind direction angle. This process ensures that the wind direction angle and the azimuth angle of the micro-topography axis are in the same axial angle system, thereby guaranteeing the consistency and stability of subsequent angle calculations.

[0069] After unifying the angle system, the minimum axial angle between the micro-topographic axis and the wind direction can be calculated. Let θ be the azimuth angle of the micro-topographic axis. r The unified wind direction angle is θ′ w Then the minimum axial angle Δ between the two can be expressed as:

[0070] Where Δ takes values ​​ranging from 0 to 1. 90 When Δ is small, it indicates that the wind direction is basically consistent with the direction of the micro-topography axis; when Δ is close to 90... This indicates that the wind direction is nearly perpendicular to the axis.

[0071] Using the above method, the corresponding wind direction value and the minimum axial angle between the axis and the wind direction can be calculated for each micro-topographic axis. The relevant results are recorded as axis attribute fields, such as axis azimuth, wind direction angle, and minimum axial angle. This indicator can quantitatively reflect the spatial relationship between the ridge or canyon axis and the prevailing wind direction, providing an important basis for the subsequent assessment of transmission lines crossing micro-topographic sections.

[0072] Calculate the normal relative elevation difference index of the micro-topographic axis: Specifically, the following steps are included: Along the micro-topographic axis, center points of the directional profile are arranged at preset intervals, and a normal profile line orthogonal to the axis direction is constructed at each center point; let the local tangential direction of a certain micro-topographic axis at a certain location be vector t=(dx,dy). Where dx and dy are the direction components of the axis in the plane coordinate system. The unit normal direction orthogonal to the axis direction can be expressed as:

[0073] Using the normal direction as a reference, profile center points are arranged at certain intervals along the axis, and a normal profile line is constructed at each center point. Let the half-width of the profile be D. Then, each profile extends a distance D from its center point along the normal direction to both sides, forming a complete profile segment. In practical applications, the half-width of the profile can be set according to the topographic scale of the study area. For example, in micro-topographic analysis of mountainous areas, the half-width of the profile can be set to approximately 1 km to ensure that the profile can cover the main topographic relief areas on both sides of ridges or valleys. Elevation sampling is performed on the normal profile lines using a digital elevation model (DEM) to obtain the elevation sequence of the profile. After constructing the normal profile, the elevation along the profile lines can be sampled using a DEM. Specifically, several sampling points are arranged at preset intervals on each normal profile, and the elevation values ​​at the corresponding locations are read from the DEM raster to form the elevation sequence of the profile.

[0074] Let the elevation at the center point of the profile be z0, then the elevation sequences on both sides of the profile are denoted as follows:

[0075]

[0076] By analyzing the elevation sequence on both sides of the profile, the elevation difference between the center of the axis and the lowest point of the terrain on both sides can be obtained, thus characterizing the relative height features of the micro-topography at that location. Calculate the elevation difference between the center point of each profile and the lowest points on both sides, and take the larger of the elevation differences on both sides as the relative elevation difference of the profile. Statistical calculations were performed on the relative elevation differences of all profiles along the axis to obtain a set of statistical indicators describing the intensity of micro-topographic undulations. These unified indicators include, but are not limited to, the maximum value, average value, and percentile value of the relative elevation differences. To comprehensively reflect the topographic undulation characteristics along the micro-topography axis, this patent performs statistical analysis on the elevation difference results of multiple normal profiles. For a single profile, the elevation difference between the center point of the axis and the lowest elevations on both sides of the profile can be calculated separately to obtain the relative elevation difference H on the left side. left relative height difference H with the right side right .

[0077]

[0078]

[0079] Furthermore, the larger of the elevation differences on both sides can be taken as the relative elevation difference H of the profile. rel ,Right now:

[0080] After establishing multiple profiles along the axis, the relative elevation differences of all profiles can be statistically calculated to obtain a set of statistical indicators describing the intensity of micro-topographic undulations. For example, the maximum, average, and percentile values ​​of the relative elevation differences can be calculated. Among these, the percentile value indicator can reduce the impact of local abnormal elevation differences on the overall results, thus more stably reflecting the overall level of topographic undulations on both sides of the axis.

[0081] Using the methods described above, a set of relative elevation difference indexes describing the topographic undulations can be constructed for each micro-topographic axis, thereby achieving a quantitative characterization of the topographic intensity on both sides of ridges or valleys. These indexes not only reflect the asymmetric characteristics of the micro-topographic structure but also provide important basis for the segmented evaluation of subsequent transmission lines crossing micro-topographic sections.

[0082] Calculate the spatial relationship between each transmission line segment and the micro-topographic axis.

[0083] Specifically, after obtaining the segmented data of the transmission line, the micro-topographic axis data, and the corresponding axis-wind direction angle and relative elevation difference, this patent uses the line segment as the smallest analysis unit to systematically analyze the spatial coupling relationship between the transmission line and the micro-topography. Assume the transmission line is divided into n continuous line segments:

[0084] Where L i Let represent the i-th route segment. For each route segment, it is necessary to analyze its spatial relationship with the axis of the adjacent ridge or canyon, and combine this with the previously calculated minimum axial angle Δ between the axis and wind direction, and the micro-topography normal relative elevation difference index H.rel We construct micro-terrain coupling features at the line segment level.

[0085] This segmented analysis framework avoids the problem of spatial information averaging caused by analyzing the entire transmission line as a whole, allowing different line sections to reflect the topography and wind conditions of their respective areas, thereby improving the spatial accuracy and engineering applicability of the assessment results.

[0086] Robustness assessment method for crossing ridges or canyons When determining the relationship between line segments and micro-topographic axes, this patent proposes a robust crossing determination mechanism to identify whether the transmission line crosses key terrain structures such as ridges or canyons.

[0087] Let the i-th line segment be L i The j-th micro-topographic axis is R j Traditional methods typically rely solely on geometric intersection relationships for judgment. However, in real-world engineering scenarios, there may be situations where the line and axis overlap, cross at extremely close distances, or fail to intersect strictly due to geometric errors. Therefore, relying solely on intersection relationships can easily lead to missed judgments.

[0088] Therefore, this application incorporates the three spatial relationships of intersection, overlap, and proximity into a unified framework for determining crossing. Let: I(L i ,R j This indicates whether the route segment intersects with the micro-topographic axis; O(L i ,R j The ) indicates whether there is significant overlap between the two; d(L i ,R j This indicates the minimum spatial distance between the line segment and the axis. τ is a preset distance threshold.

[0089] The determination function for whether a line segment crosses a micro-topographic axis can be expressed as:

[0090] in This indicates that the route segment has been determined to cross the corresponding micro-topographic axis.

[0091] In actual calculations, to improve decision-making efficiency, candidate axes can be filtered using spatial indexing and buffer zones, and precise spatial relationship calculations can be performed only on these candidate axes. When the candidate axis set is empty, a nearest-distance strategy can be used to select the micro-topographic axis closest to the route segment as the reference object, i.e.:

[0092] The above mechanism can effectively avoid the problem of missed judgments caused by spatial errors or data discontinuity, thereby improving the stability of power transmission line crossing ridges or canyons.

[0093] By coupling the minimum axial angle, normal relative elevation difference index, and spatial relationship between the transmission line segment and the micro-topographic axis for each transmission line segment, a multi-dimensional risk profile of the transmission line segment is constructed. After determining the crossing relationship between the line segments and the micro-topography axis, this patent further combines the minimum axial angle Δ between the axis and wind direction with the micro-topography normal relative elevation difference index H. rel The micro-topography coupling assessment results at the segment level of the transmission line are constructed.

[0094] Where: C i Indicates whether the i-th line segment crosses a micro-topographic axis; Δi represents the minimum axial angle between the axis and the prevailing wind direction; H rel This indicates the relative elevation difference between the two sides of the micro-topographic axis.

[0095] This allows for the construction of a micro-topography-wind field coupled feature vector for each line segment:

[0096] Where P i This represents the micro-topographic coupling risk profile of the i-th route segment. This profile can simultaneously characterize whether the route segment crosses key topographic structures, the spatial relationship between the topographic axis and the prevailing wind direction, and the intensity of topographic undulations on both sides of the axis.

[0097] In practical applications, the above assessment results can be written into the line segment attribute fields, such as crossing markers, corresponding micro-topographic axis numbers, line segment azimuth, axis-wind direction angle, and canyon or ridge crossing markers, thus forming structured segment assessment results. These results not only enable quantitative comparisons between different line segments but also provide important spatial analysis basis for transmission line icing risk analysis, wind-induced disaster assessment, and route selection optimization.

[0098] Using the above methods, this patent constructs a segmented evaluation framework for transmission lines that integrates micro-topographic structure, wind direction field information, and topographic undulation features, realizing the quantitative identification and structured expression of the coupling relationship between transmission lines, micro-topography, and wind field in complex terrain areas.

[0099] A transmission line segmentation assessment system coupled with micro-topographic axis and wind direction includes: a processing module for executing the transmission line segmentation assessment method coupled with micro-topographic axis and wind direction.

[0100] Example Taking the mountainous power transmission line corridor in Anhui Province as the research area, this paper describes the proposed method for determining and evaluating the coupling of power transmission lines, micro-topography, and wind fields.

[0101] The data used in this embodiment includes digital elevation model (DEM) data, transmission line vector data, and regional prevailing wind direction raster data. The DEM data is derived from publicly available topographic data products, with a spatial resolution of approximately 12.5 m.

[0102] First, topographic relative elevation difference analysis was performed using DEM data to construct initial mask data for ridge and canyon areas. Since the original mask data may contain local noise, small-scale holes, or regional fractures, morphological processing was performed on the mask data before skeleton extraction to improve the stability of the axis extraction results. For example... Figure 2 As shown, morphological closing operations are used to smooth and enhance the connectivity of the mask data. Small-scale holes are filled and adjacent areas are connected by dilation followed by erosion, thereby obtaining a terrain area mask with a more continuous structure.

[0103] After completing the mask optimization process, skeletonization calculations were performed separately for the ridge area and the canyon area, such as... Figure 3 , Figure 4 As shown, the central axis structure is extracted to obtain the ridge axis and canyon axis. To reduce noise interference, the extracted axis results are subjected to length filtering. In this embodiment, the minimum retention length of the canyon axis is set to 30 m to ensure the stability of the micro-topographic axis structure.

[0104] After obtaining the ridgeline and canyon axes, the transmission line is segmented. Based on the line geometry, the original transmission line is divided into several shorter segments, and the directional angles of each segment, as well as the ridgeline and canyon axes, are calculated to establish the directional relationship between the line and the micro-topographic axes.

[0105] Building upon this foundation, an axial angle criterion is introduced to describe the geometric relationship between the transmission line and the micro-topographic structure. For each line segment, the axial angle Δ between the line direction and the ridge axis and the canyon axis is calculated, with the angle range limited to 0°–90°. Subsequently, a ridge-canyon dual-structure determination framework is constructed. For each line segment, its spatial relationship with both the ridge axis and the canyon axis is analyzed simultaneously. Combining the axial angle and spatial distance information, the system identifies two typical topographic structures: the line crossing a ridge or traversing a canyon. This allows for a more comprehensive characterization of the micro-topographic influence features within the transmission line corridor.

[0106] In the spatial relationship determination process, this embodiment employs a robust crossing recognition mechanism. When determining whether a route crosses a ridge or canyon, the geometric intersection, contact, or overlap between the route segment and the terrain axis, as well as the spatial distance between them, are comprehensively considered. When one of these conditions is met, it is determined that the route segment crosses the corresponding terrain structure. In this embodiment, the ridge crossing determination distance threshold is set to 50 m, and the canyon crossing determination distance threshold is also set to 50 m. This determination strategy effectively reduces the impact of spatial data errors on the recognition results and improves the reliability of crossing recognition.

[0107] After identifying the route-terrain coupling relationship, regional prevailing wind direction grid data is introduced for risk analysis. The prevailing wind direction data is stored in grid form, with each grid cell recording the wind direction angle at its corresponding location. For each route segment, samples are taken from the wind direction grid based on its spatial location to obtain the prevailing wind direction information for the corresponding area, and the axial angle between the route direction and the prevailing wind direction is calculated. This angle is used to assess the degree of wind field impact that different route segments may experience under specific wind direction conditions.

[0108] like Figure 5 , Figure 6 As shown, after completing the above analysis, corresponding micro-topographic coupling attribute information is generated for each line segment, including line direction angle, ridge crossing identifier, corresponding ridge axis number, angle between line and ridge axis, canyon crossing identifier, and angle between line and canyon axis. The analysis results are then written into a new line vector data file to form a complete micro-topographic coupling evaluation result for the transmission line.

[0109] As demonstrated in this embodiment, the method of the present invention can automatically extract the axial structure of ridges and canyons under large-scale DEM data conditions, and, combined with the line segment direction information, identify the coupling relationship between transmission lines and micro-topographic structures. Compared with traditional methods that rely solely on terrain slope or single spatial overlay analysis, the present invention, by introducing axial angle criteria, ridge-canyon dual-structure analysis, and robust crossing identification mechanism, can more accurately identify the spatial structural characteristics of transmission lines crossing ridges or canyons, thereby providing a reliable data foundation for transmission line wind field analysis and engineering risk assessment.

[0110] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0111] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., 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 segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction, characterized in that, Includes the following steps: The transmission line is divided into segments, and the axial azimuth angle of each segment is calculated. Determine the azimuth angle of the micro-topography axis and the prevailing wind direction angle at its location, and then calculate the minimum axial angle between the two after converting them to a unified angle measurement system. Calculate the normal relative elevation difference index of the micro-topographic axis; Calculate the spatial relationship between each transmission line segment and the micro-topographic axis, and determine whether the transmission line segment crosses the micro-topographic axis based on the spatial relationship; The minimum axial angle, the normal relative elevation difference index, and the determination result of whether the transmission line segment crosses the micro-topographic axis are coupled together to construct a multi-dimensional risk profile of the transmission line segment.

2. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, The entire transmission line is divided into multiple continuous transmission line segments by directly generating the original line node structure or by subdividing it according to a preset length. The axial azimuth angle of each transmission line segment is determined by the coordinates of the beginning and end points of the line segment and mapped to an axial angle range of 0° to 180°.

3. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, The micro-topography axis extraction method includes the following steps: Construct a binary mask grid for micro-topography; Morphological closing operations are performed on the mask to fill holes and enhance connectivity; The processed mask is then subjected to skeletonization to obtain a skeleton structure with a single pixel width. Continuous paths are traced based on the spatial adjacency relationships of skeleton pixels, and vectorized to generate micro-topographic axes.

4. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 3, characterized in that, The azimuth angle of the micro-topography axis is θ r ,and: Where (x1, y1) are the starting coordinates of the micro-topography axis, (x2, y2) are the ending coordinates of the micro-topography axis, and atan2 is the two-parameter arctangent function.

5. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, When obtaining the prevailing wind direction angle at the location of the micro-topography axis, the wind direction value is read from the wind direction grid data by sampling at the center point of the axis or by averaging multiple sampling points along the axis.

6. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, Convert the prevailing wind direction angle and the axial azimuth angle of the micro-topography axis to the same angle measurement system, that is: in: This indicates the converted axial wind direction angle. This indicates the axial wind direction angle before the conversion.

7. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, The minimum axial included angle Δ is: Where: θ r Let θ′ be the azimuth angle of the micro-topographic axis. w The unified wind direction angle, Δ, has a range of 0. 90 .

8. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, The calculation of the normal relative elevation difference index of micro-topographic axes includes the following steps: Along the micro-topography axis, center points of the directional profile are arranged at preset intervals, and a normal profile line orthogonal to the axis direction is constructed at each center point; The elevation of the normal profile line is sampled using a digital elevation model to obtain the elevation sequence of the profile. Calculate the elevation difference between the center point of each profile and the lowest points on both sides, and take the larger of the elevation differences on both sides as the relative elevation difference of the profile. Statistical calculations are performed on the relative height differences of all profiles along the axis to obtain a set of statistical indicators describing the intensity of micro-topographic undulations. These statistical indicators include, but are not limited to, the maximum value, average value, and percentile value of the relative height differences.

9. The method for segmented evaluation of transmission lines coupled with micro-topographic axis and wind direction according to claim 1, characterized in that, When determining whether a transmission line segment crosses a micro-topographic axis, if the transmission line segment and the micro-topographic axis have geometric intersection, spatial overlap, or a minimum spatial distance less than or equal to a preset threshold, then the transmission line segment is determined to cross the micro-topographic axis.

10. A segmented evaluation system for transmission lines coupled with micro-topographic axis and wind direction, characterized in that, include: The processing module is used to execute the transmission line segmentation evaluation method based on the coupling of micro-topographic axis and wind direction as described in any one of claims 1 to 9.

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