Methods, systems, media, and processors for locating easily loosened areas of transmission tower bolts

Abstract

This invention discloses a method, system, medium, and processor for locating easily loosened bolt areas on power transmission towers, relating to the field of power transmission line operation and maintenance testing technology. It solves the problem that existing methods for detecting bolts on power transmission towers struggle to accurately identify and precisely locate easily loosened bolt areas. This invention uses bolt clusters as the identification target, integrating tower structural topology, three-dimensional spatial location, wind load, conductor tension load paths, and historical correction states to pre-screen first-line candidate easily loosened areas. A path coverage matrix binds the shock wave propagation path to the candidate areas, and the target area is located based on abnormal vibration response. A closed-loop update is achieved by associating spatial positioning codes with health baseline signals, verification results, and historical correction states. This improves the accuracy and traceability of easily loosened bolt area identification and location, reduces inspection workload, and supports rapid detection and fixed-point verification.

Description

Technical Field

[0001] This invention relates to the field of power transmission line operation and maintenance testing technology, and in particular to a method, system, medium and processor for locating easily loosened areas of power transmission tower bolts. Background Technology

[0002] Transmission towers are the core supporting structure of overhead transmission lines, and their safe and stable operation directly affects the reliability of the power grid. The towers are connected as a whole by numerous bolts, linking components such as tower legs, main members, diagonal members, crossarms, node plates, conductor suspension points, and ground wire supports. These bolted connections are subjected to complex alternating loads over long periods, including conductor tension, wind loads, ground wire tension, temperature changes, and environmental vibrations. During continuous operation, bolts are prone to preload decay due to fatigue, micro-vibration, installation deviations, or material creep, leading to potential loosening. If not detected and addressed promptly, loose bolts can cause node slippage, member instability, or even tower collapse. Therefore, effectively detecting and locating loose bolts on transmission towers is a crucial aspect of transmission line operation and maintenance. Currently, the industry has developed various bolt detection methods, including manual inspection, torque wrench verification, image recognition based on drones, and local vibration detection based on accelerometers or laser vibration measurements. Manual inspections rely on maintenance personnel climbing towers for visual inspection or using binoculars, which is inefficient and difficult to cover all concealed high-altitude connections. Torque verification requires contact operation, which is difficult to implement at heights. Image recognition technology judges whether there is obvious displacement or corrosion by photographing the appearance of bolts, but it lacks the ability to identify minor loosening caused by early preload decay. Local vibration detection collects vibration signals by placing sensors at specific locations, which can reflect the dynamic characteristics of local structures, but the correspondence between the detected signals and the actual spatial position of the bolts is vague, making it difficult to trace back to specific areas prone to loosening. The above methods alleviate the pressure of bolt condition detection to some extent, but overall they are still in a single-point, single-signal, single-condition detection mode, failing to form a systematic area identification and precise positioning capability.

[0003] Existing technologies suffer from difficulties in accurately identifying and precisely locating areas prone to bolt loosening. Current detection methods typically focus on a single bolt or a single measuring point, lacking comprehensive utilization of the overall tower structure topology, load transmission paths, and historical maintenance data. This results in a single detection basis, weak correlation between abnormal signals and bolt spatial location, and the inability to incorporate historical inspection and re-tightening results into subsequent identification decisions. Consequently, candidate areas are frequently missed, abnormal propagation paths are misjudged, and target area positioning deviations occur frequently, making it difficult to accurately screen and precisely locate areas prone to bolt loosening.

[0004] Therefore, there is an urgent need for a method, system, medium, and processor for locating easily loosened areas of transmission tower bolts. Summary of the Invention

[0005] To address the problem that existing methods for detecting loose bolts on power transmission towers struggle to accurately identify and precisely locate areas prone to loosening, this invention provides a method, system, medium, and processor for locating these areas. This improves the accuracy, completeness, and traceability of identifying loose bolt areas, reduces the workload of manual high-altitude inspections, enhances the efficiency of detecting potential bolt loosening issues, and provides technical support for rapid detection, targeted verification, and closed-loop management of power transmission tower bolt conditions. The specific technical solution is as follows: A method for locating easily loosened areas of transmission tower bolts includes the following steps: A structural topology model of the transmission tower is established, and the transmission tower is divided into multiple bolt group areas based on the structural topology model; Based on the wind load parameters, conductor tension parameters, tower type parameters and member connection parameters obtained in advance, the load transfer path and structural response of each bolt group area are determined. Combined with the historical correction state setting conditions of each bolt group area, the bolt group area that meets the setting conditions is determined as the first candidate easy loosening area. Determine the excitation point and detection point on the transmission tower, establish the shock wave propagation path, and bind the shock wave propagation path with the first candidate loose area to form a path coverage matrix; An impact excitation is applied at the excitation point, and a response signal is collected at the detection point. The features of the response signal are extracted and compared with a reference signal to determine the abnormal propagation path. The target vulnerable areas are determined based on the path coverage matrix and abnormal propagation paths; Obtain the on-site verification results of the target easily loosened area and update the historical correction status of the corresponding bolt group area.

[0006] Preferably, the structural topology model includes topological nodes, topological edges, and node attributes. The topological nodes correspond to tower material connection positions, node plate positions, conductor hanging point positions, or ground wire bracket connection positions; the topological edges correspond to main members, diagonal members, crossarms, or other members; and the node attributes include at least the height layer, orientation side, connection plate number, member type, and number of bolts.

[0007] Preferably, the transmission tower is divided into bolt group regions based on topological nodes, topological edges, and connecting plates, including one or more non-conflicting classification methods as follows: Prioritize grouping multiple bolts on the same connecting plate into the same bolt group area; When multiple members are connected to the same connecting plate at the same time, the bolts on the connecting plate are further divided into multiple bolt group areas according to the connection direction of the members. When different topological nodes are connected to the two ends of the same member, the bolts at both ends of the member are divided into different bolt group regions. When multiple bolts are located on the same main load transmission path, and the spatial distance between adjacent bolt groups is less than the preset merging distance, the multiple bolts are divided into the same bolt group area.

[0008] Preferably, the first candidate easily loosened region is determined, including: The load transfer path is determined, which includes the tension transfer path, the wind load transfer path, and the self-weight transfer path. Specifically, the tension transfer path is obtained based on the conductor tension parameters, tower type parameters, and member connection parameters; the wind load transfer path is obtained based on the wind load parameters, tower type parameters, and member connection parameters; and the self-weight transfer path is obtained based on the tower type parameters and member connection parameters. Calculate the structural response, which includes the tower material stress, nodal displacement, member vibration response, load transfer state, and response difference with the symmetrical region of the structure corresponding to each bolt group region; The filtering conditions are set, including structural location conditions, load path conditions, and structural response conditions. The structural location condition is that the bolt group area is located in at least one pre-defined structural location. The load path condition is that the bolt group area is located on at least one path of tension transmission path, wind load transmission path, and self-weight transmission path. The structural response condition is to compare the structural response of each bolt group area with the corresponding reference object. When any structural response exceeds the corresponding anomaly threshold, the bolt group area is determined to meet the structural response condition. Obtain historical correction states, which include enhanced states, maintained states, and suppressed states; Determine the region to be screened: Compare each bolt group region with the structural location condition, load path condition, and structural response condition. If any bolt group region satisfies the structural response condition and at least one of the structural location condition or load path condition, then the bolt group region is determined as the region to be screened. If any bolt group region has a historical correction state that is an enhanced state and satisfies at least one of the structural location condition or load path condition, then the bolt group region is also determined as the region to be screened. Identifying the first candidate loosening region: The region to be screened is further screened based on its historical correction status. When the historical correction status of the region to be screened is an enhanced state or a maintained state, the region to be screened is identified as the first candidate loosening region. When the historical correction status of the region to be screened is an inhibited state, the region to be screened is identified as the first candidate loosening region only if it meets the preset strong response conditions. The preset strong response conditions include the bolt group region meeting the response anomaly conditions under two or more wind direction conditions, or the response difference between the bolt group region and its structural symmetrical region meeting the preset inconsistency conditions, or the bolt group region being located at both the tower section change position and the main load transmission path, or the historical re-tightening torque change record of the bolt group region meeting the preset torque change conditions.

[0009] Preferably, the path coverage matrix records the shock wave propagation path corresponding to each set of excitation points and detection points, as well as the coverage relationship between the shock wave propagation path and the first candidate easily loosened area. The coverage relationship includes whether it passes through, whether it is adjacent, topological distance, and whether it is the main propagation path or the auxiliary propagation path. If no propagation path passes through or is adjacent to the current first candidate easily loosened area, an auxiliary detection point or an auxiliary excitation point is reselected and the matrix is ​​updated.

[0010] Preferably, determining the abnormal propagation path includes: Search for at least one topological path from the excitation point to the detection point in the structural topology model, and record the topological nodes, topological edges and connecting plates passed through as the shock wave propagation path. When the first candidate loose area is located on the propagation path, or its topological distance is not greater than the preset adjacent distance threshold, the area is bound to the propagation path. There is one main propagation path and at least one auxiliary propagation path between the same excitation point and the detection point. An impact excitation is applied, a response signal is acquired, and signal features are extracted. The signal features include the arrival time of the shock wave, the response amplitude, the amplitude attenuation degree, the main frequency change, the phase change, and the high-frequency envelope abrupt change. The signal characteristics are compared with the signal characteristics of a reference signal, which can be a health benchmark signal, a historical detection signal, a signal from a symmetrical region on the same tower, or a theoretical propagation response. When the arrival time delay of the shock wave exceeds a preset time difference threshold, the response amplitude attenuation exceeds a preset amplitude difference threshold, the main frequency offset exceeds a preset frequency difference threshold, the phase difference exceeds a preset phase difference threshold, or the high-frequency envelope mutation exceeds a preset envelope mutation threshold, the propagation path is determined to be an abnormal propagation path.

[0011] Preferably, the target's vulnerable areas are determined based on the path coverage matrix and the anomaly propagation path, including: An abnormal path association table is constructed, which is used to record the number of times each first candidate loosening region is bound by an abnormal propagation path, the minimum topological distance between each abnormal propagation path, the historical correction status, whether it is located on the main load transmission path, and whether there is an abnormal propagation path with structural symmetry. Determine the target's easily loosened area based on any one or more of the following rules: When two or more abnormal propagation paths are bound to the same first candidate loosening region, and the topological distance between the region and each abnormal propagation path is not greater than a preset distance threshold, the first candidate loosening region is determined as the target loosening region. When multiple first candidate loosening regions meet the above conditions, they are sorted in the following order: the number of bindings along the abnormal propagation path from most to least, the minimum topological distance from smallest to largest, and priority is given to regions located on the main load transfer path or those with structural symmetry paths. The first candidate loosening region ranked first is then determined as the target loosening region. When an abnormal propagation path binds multiple first-candidate loosening regions, they are sorted in ascending order of topological distance, and the region ranked first is determined as the target loosening region; if there are multiple regions ranked first and with the same topological distance, the region with a historical correction state of enhanced state is selected first, and the region located on the main load transmission path is selected second. When the topological distance is the same, the historical correction status is the same, and all regions are located or not located on the main load transfer path, multiple regions are marked as regions to be reviewed.

[0012] A system for locating easily loosened bolt areas on power transmission towers, applied to the method described above, includes: Modeling and Partitioning Module: Establish a structural topology model of the transmission tower, and divide the transmission tower into multiple bolt group areas based on the structural topology model; First candidate loosening area acquisition module: Based on the pre-acquired wind load parameters, conductor tension parameters, tower type parameters and member connection parameters, determine the load transfer path and structural response of each bolt group area. Combined with the historical correction state setting conditions of each bolt group area, the bolt group area that meets the setting conditions is determined as the first candidate loosening area. Abnormal propagation path acquisition module: Determine the excitation point and detection point on the transmission tower, establish the shock wave propagation path, and bind the shock wave propagation path with the first candidate loose area to form a path coverage matrix; apply shock excitation at the excitation point, collect response signals at the detection point, extract the features of the response signals and compare them with the health benchmark signal to determine the abnormal propagation path; The results output and update module determines the target loose area based on the path coverage matrix and the anomaly propagation path; obtains the on-site verification results of the target loose area, and updates the historical correction status of the corresponding bolt group area.

[0013] A computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the method for locating easily loosened areas of transmission tower bolts as described above.

[0014] A processor for running a program, wherein the program executes the method for locating easily loosened areas of transmission tower bolts as described above.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses bolt clusters as the identification target and unifies the topological relationship of the transmission tower structure, its three-dimensional spatial position, wind load and conductor tension load paths, elastic shock wave propagation paths, vibration response anomaly characteristics, and historical re-tightening records. Before testing, it can screen first-candidate easily loosened areas based on structural stress and historical conditions, reducing the scope of blind testing. During testing, the path coverage matrix and propagation path binding relationship enable the vibration response signal to be reverse-located to specific candidate areas, improving the correspondence accuracy between abnormal signals and actual bolt areas. After testing, the reliability of locating target easily loosened areas is improved through anomaly path association tables, connection stiffness status, structural symmetry difference grading, and area sorting rules. Simultaneously, spatial positioning coding continuously associates the target area, health baseline signal, on-site verification results, re-tightening records, and historical correction status, enabling subsequent testing to automatically correct identification rules based on historical data. Therefore, this invention can improve the accuracy, completeness and traceability of identifying easily loosened areas of transmission tower bolts, reduce the workload of manual high-altitude inspections, improve the efficiency of discovering potential bolt loosening hazards, and provide technical support for rapid detection, fixed-point verification and closed-loop operation and maintenance management of transmission tower bolt status. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0018] 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, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0020] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0022] In one embodiment of the present invention, such as Figure 1 As shown, This invention provides a method for locating easily loosened bolt areas on power transmission towers. Based on the structural topology and three-dimensional spatial relationships of the tower, the method divides the tower into multiple bolt group areas and combines wind load, conductor tension transmission, historical inspection results, and elastic shock wave response signals to identify and locate easily loosened areas. This invention does not directly use individual bolts as the detection object, but rather uses bolt group areas as the identification object. First, it identifies the first candidate easily loosened areas that may exhibit bolt loosening trends. Then, it verifies these first candidate areas using shock wave propagation paths and vibration response signals. Finally, it converts the target easily loosened areas into spatial location codes and updates historical records using on-site verification or tightening results.

[0023] In this embodiment, a transmission tower refers to a steel structure tower used to erect transmission line conductors, ground wires, or lightning protection wires. It includes tower legs, main members, diagonal members, crossarms, node plates, conductor suspension points, ground wire supports, and bolts connecting the aforementioned structural components. A bolt group area refers to an area composed of multiple bolts located at the same topological node, the same connecting plate, the same member connection end, or between adjacent topological nodes, and having the same or similar load transfer relationships. A bolt group area may include multiple bolts on the same node plate, multiple bolts at the same member end connection position, or multiple bolts within the same tower section located on the same main load transfer path.

[0024] This embodiment includes the following steps: S1: Establish a structural topology model of the transmission tower, and divide the transmission tower into multiple bolt group areas based on the structural topology model; In practical implementation, the structural parameters of the transmission tower are first obtained. These parameters include tower type, tower height, tower segment division, member numbering, node numbering, connection plate numbering, conductor suspension point location, ground wire support location, and bolt arrangement location. An initial structural topology model can be established based on the transmission tower design drawings. Specifically, the tower legs, main members, diagonal members, crossarms, node plates, conductor suspension points, and ground wire supports are taken as structural units. The connection points between adjacent structural units are taken as topological nodes, and the members between adjacent topological nodes are taken as topological edges, thus forming a structural topology model composed of topological nodes and topological edges.

[0025] When UAV inspection images or LiDAR point clouds are available, the initial structural topology model can be spatially corrected based on these images or clouds. Correction includes the actual spatial positions of members, node plate positions, crossarm inclination angles, tower leg inclination angles, and node heights. If there are discrepancies between the design drawings and the actual site structure, the structural topology model can be corrected using on-site ranging, angle measurements, or image recognition results. Based on the structural topology model, a three-dimensional spatial positioning model is established. This model uses the center of the transmission tower base or a pre-set tower leg foundation point as the origin, establishing coordinate axes for height, line direction, and transverse line direction. Each topology node, topology edge, connecting plate, and bolt group area is mapped to this spatial coordinate system. The height direction represents the tower segment where the target area is located, the line direction represents the position along the transmission line, and the transverse line direction represents the position perpendicular to the transmission line.

[0026] After establishing the structural topology model, the transmission tower is divided into bolt group regions based on topological nodes, topological edges, and connecting plates. In one embodiment, multiple bolts on the same connecting plate are preferentially classified into the same bolt group region. When multiple members are connected to the same connecting plate, the bolts on the connecting plate are further classified into multiple bolt group regions according to the connection direction of the members. When different topological nodes are connected to both ends of the same member, the bolts at both ends of the member are classified into different bolt group regions. When multiple bolts are located on the same main load transmission path, and the spatial distance between adjacent bolt groups is less than a preset merging distance, the multiple bolts can be classified into the same bolt group region. When there are inner, outer, line-side, or cross-line-side bolts at the same node, bolt group numbers are set according to their orientation.

[0027] Each bolt group area is configured with an area foundation code and area attribute information. The area foundation code includes the tower segment number, member number, node number, and bolt group number. The area attribute information includes the tower segment, member, node, connecting plate, orientation, whether it is located on the main load transfer path, whether it is located in a symmetrical position of the structure, whether it is located at a position where the tower body cross-section changes, whether there are any historical loosening records, and whether there are any historical re-tightening records.

[0028] S2: Based on the wind load parameters, conductor tension parameters, tower type parameters and member connection parameters obtained in advance, determine the load transfer path and structural response of each bolt group area. Combined with the historical correction state setting conditions of each bolt group area, the bolt group area that meets the setting conditions is determined as the first candidate easy loosening area. For example, when determining the load transfer path, the topological nodes and edges in the structural topology model can be used as the basis, with conductor suspension points, ground wire suspension points, crossarm roots, tower leg foundation nodes, and main member splicing nodes as key load transfer nodes. For conductor tension or ground wire tension, the tension transfer path can be obtained by starting from the conductor suspension point or ground wire suspension point and searching along the crossarm, main member, diagonal member, and tower leg directions to the tower leg foundation node. For wind loads, the connection relationship between the windward members, crossarm connection nodes, main member nodes, and tower leg nodes can be determined as the wind load transfer path according to the wind direction. For the tower's self-weight, the self-weight transfer path can be determined from top to bottom along the height direction. If a bolt group area is located on any of the above load transfer paths, or at the intersection of two or more load transfer paths, then the bolt group area is considered to satisfy the load path conditions.

[0029] In this embodiment, the structural response can be obtained through finite element analysis, equivalent truss analysis, historical measured response analysis, or a combination of the above methods. When using finite element analysis, the main members, diagonal members, crossarms, and tower legs of the transmission tower can be equivalently represented as truss elements or beam elements, with the node plates and bolt connection positions as connection nodes. The stress state of each topological node and topological edge is calculated based on wind load parameters, conductor tension parameters, and tower type parameters. When using equivalent truss analysis, the transmission tower can be simplified into a stress network composed of topological nodes and topological edges based on the member connection relationships and load transfer directions. The relative structural response of each bolt group region is determined based on the location of each member and the load transfer path. The structural response is not limited to absolute stress values ​​or absolute displacement values; it can also be the relative response ranking within the same tower segment, the response difference within the same height layer, the response difference between symmetrical regions of the same structure, or the number of responses occurring under multiple wind direction conditions.

[0030] Furthermore, based on the stress state, the tower material stress, nodal displacement, member vibration response, load transfer state, and response differences with the symmetrical structural regions corresponding to each bolt group region are determined. The symmetrical structural region refers to a bolt group region located at the same height level, having the same or similar structural form, and arranged symmetrically with respect to the tower centerline or the direction of the line.

[0031] When determining the first candidate easily loosened area, the regional attribute information, structural response, and load transfer path of each bolt group area are divided into structural location conditions, load path conditions, and structural response conditions. The structural location conditions include the bolt group area being located at at least one of the following: at the root of the crossarm, at a tower leg with a variable cross-section, at a main member splice, at the intersection of diagonal members, at a concentrated connection of node plates, near a conductor hanging point, or at a ground wire support connection. The load path conditions include the bolt group area being located on at least one of the following paths: conductor tension transfer path, ground wire tension transfer path, wind load transfer path, and tower self-weight transfer path, or at the intersection of the above load transfer paths. The structural response conditions are determined by comparing the structural response of each bolt group area with a corresponding benchmark object. When any structural response exceeds the corresponding abnormal threshold, the bolt group area is deemed to meet the structural response conditions. The benchmark object can be the average response of other bolt group areas in the same transmission tower, the average response of bolt group areas within the same height layer, the response value of a structurally symmetrical area, the historical normal response value of the same type of transmission tower, the initial response value during the construction and acceptance phase, or a manually calibrated response threshold.

[0032] For example, the process of determining the first candidate easily loosened region is as follows: S201: Determine the region to be screened: When any bolt group region satisfies at least one structural response condition and at least one of a structural location condition or a load path condition, the bolt group region is determined as a region to be screened. Furthermore, when the historical correction state of any bolt group region is an enhanced state, and the bolt group region satisfies at least one of a structural location condition or a load path condition, the bolt group region is also determined as a region to be screened.

[0033] S202: Determine the first candidate easily loosened region: Further filter the region to be screened by combining it with the historical correction state. When the historical correction state of the region to be screened is an enhanced state or a maintained state, the region to be screened is determined as the first candidate easily loosened region. When the historical correction state of the region to be screened is an inhibited state, if the region to be screened meets the preset strong response condition, the region to be screened is determined as the first candidate easily loosened region.

[0034] The preset strong response conditions include the bolt group area meeting the response anomaly conditions under two or more wind direction conditions, or the response difference between the bolt group area and its structural symmetrical area meeting the preset inconsistency conditions, or the bolt group area being located at both the tower section change position and the main load transmission path, or the historical re-tightening torque change record of the bolt group area meeting the preset torque change conditions.

[0035] Historical correction states include enhanced, maintained, and suppressed states. When repeated loosening records exist for the same spatial location code or structural location type within a preset number of inspections, the historical correction state of the corresponding bolt group area is set to enhanced. Repeated loosening records may include multiple on-site verifications confirming loosening, multiple instances where the torque before tightening is lower than a preset torque threshold, or multiple instances where the torque difference before and after tightening exceeds a preset torque difference threshold. When there are no repeated loosening records for the same spatial location code or structural location type in the historical inspection records, and no consecutive normal records, the historical correction state of the corresponding bolt group area is set to maintained. When there are no loosening confirmation records for the same spatial location code or structural location type within a preset number of inspections, and the torque difference before and after tightening does not exceed the preset torque difference threshold, the historical correction state of the corresponding bolt group area is set to suppressed. In the absence of historical inspection records or tightening records, the historical correction state of the corresponding bolt group area can be set to maintained.

[0036] S3: Determine the excitation point and detection point on the transmission tower, establish the shock wave propagation path, and bind the shock wave propagation path with the first candidate easily loosened area to form a path coverage matrix; After identifying the first candidate loosening area, at least one excitation point and at least one detection point are determined in the three-dimensional spatial positioning model. The excitation point can be set at the main members of the tower leg, the main members of the tower body, the root of the crossarm, the splice of the main members, or a fixed location convenient for on-site operation. For the same transmission tower, one main excitation point and at least one auxiliary excitation point can be set. The main excitation point is used to cover the main transmission path of the tower body, and the auxiliary excitation point is used to cover the crossarm, conductor hanging point, or local node area. The detection point can be set on the surface of the member near the first candidate loosening area, adjacent nodes of the candidate area, symmetrical areas of the structure, the root of the crossarm, or at a pre-set vibration measurement point.

[0037] When determining the excitation and detection points, a path coverage table or path coverage matrix can be established based on the distribution of the first candidate loosening regions in the 3D spatial positioning model. The path coverage table records the shock wave propagation path corresponding to each set of excitation and detection points, as well as the first candidate loosening regions that this propagation path can pass through or be adjacent to. The path coverage matrix represents the coverage relationship between each candidate excitation point, each candidate detection point, and each first candidate loosening region. An element in the path coverage matrix represents the coverage relationship between the shock wave propagation path formed from a candidate excitation point to a candidate detection point and a first candidate loosening region. This coverage relationship includes at least whether the path passes through the first candidate loosening region, whether it is adjacent to the first candidate loosening region, the corresponding topological distance, whether it belongs to the main propagation path, and whether it belongs to an auxiliary propagation path. If the shock wave propagation path directly passes through the first candidate easily loosened area, the corresponding coverage relationship is marked as passed; if the shock wave propagation path does not directly pass through the first candidate easily loosened area, but the topological distance between the two is not greater than the preset adjacency distance threshold, the corresponding coverage relationship is marked as adjacency; if the topological distance between the two is greater than the preset adjacency distance threshold, the corresponding coverage relationship is marked as uncovered.

[0038] In one implementation, the path coverage matrix can be used to determine the layout scheme of excitation points and detection points. Specifically, several candidate excitation points and candidate detection points are first selected based on a three-dimensional spatial positioning model. Then, the shock wave propagation path between each group of candidate excitation points and candidate detection points is calculated based on the structural topology model, and the number of first candidate loosening areas that can be covered by each shock wave propagation path is counted. For multiple selectable excitation points and detection points, priority can be given to selecting locations that can cover a large number of first candidate loosening areas, can cover the main load transmission path, can form a symmetrical propagation path, and are easy to deploy or detect on site as excitation points and detection points. For first candidate loosening areas located at the root of the crossarm, near the conductor hanging point, or at the tower leg cross-section, auxiliary detection points can be set up so that at least one propagation path passes through or is adjacent to the first candidate loosening area. For first candidate loosening areas whose historical correction state is an enhanced state, or first candidate loosening areas located on the main load transmission path, priority should be given to selecting combinations of excitation points and detection points that can be covered by two or more different propagation paths.

[0039] If the path coverage matrix formed by the initial excitation point and detection point cannot cover a certain first candidate loose region with the propagation path, then an auxiliary detection point or auxiliary excitation point is reselected in the 3D spatial positioning model, and the path coverage matrix is ​​updated.

[0040] S4: Apply an impact stimulus at the excitation point, collect the response signal at the detection point, extract the features of the response signal and compare it with the health baseline signal to determine the abnormal propagation path; Before applying the elastic impact excitation, a propagation path binding relationship is established between the excitation point, the detection point, and the first candidate easily loosened region. Specifically, for any excitation point and any detection point, at least one topological path from the excitation point to the detection point is searched in the structural topology model, and the topological nodes, topological edges, and connecting plates traversed by this topological path are recorded as the shock wave propagation path. When the first candidate easily loosened region is located on the shock wave propagation path, or the topological distance between it and the shock wave propagation path is not greater than a preset adjacency distance threshold, the first candidate easily loosened region is bound to the shock wave propagation path.

[0041] When establishing the propagation path binding relationship, the shock wave propagation path is the equivalent propagation path obtained based on the structural topology model. This path represents the members, nodes, and connecting plates that the elastic shock wave may pass through as it travels from the excitation point to the detection point. Since transmission towers are formed by connecting multiple members and nodes, the actual elastic shock wave may propagate along multiple member paths. Therefore, there can be one main propagation path and at least one auxiliary propagation path between the same excitation point and detection point. The main propagation path can be determined based on conditions such as the shortest topological distance, strong continuity of members along the path, and the path passing through the main material or main load transmission path. The auxiliary propagation path can be determined based on conditions such as whether it passes through the first candidate easily loosened area, whether it forms a symmetrical path with the main propagation path, and whether it passes through areas with abnormal structural response. Both the main propagation path and the auxiliary propagation path can participate in the abnormal propagation path determination.

[0042] Elastic impact excitation can be generated by a manual striking device, an electromagnetic impact device, or a piezoelectric excitation device. The elastic impact excitation can be a single pulse excitation or a series of repetitive pulse excitations. When using multiple repetitive pulse excitations, the vibration response signals from multiple pulses can be averaged, screened for consistency, or have anomalies removed. The vibration response signal can be acquired non-contactly using a laser vibration measuring device, or contact-type using an accelerometer, acoustic vibration sensor, or piezoelectric sensor. When using a laser vibration measuring device, a correspondence is established between the laser measurement point and the detection point in a three-dimensional spatial positioning model.

[0043] Before acquiring vibration response signals, the excitation device and the acquisition device can be synchronized in time, so that the excitation moment is used as the starting moment for calculating the arrival time of the shock wave. When using manual impact, the excitation start moment can be determined by the impact sensor, the hammer signal, or the moment of vibration abrupt change near the excitation point. When using an electromagnetic impact device or a piezoelectric excitation device, the control trigger signal can be used as the excitation start moment. The acquired vibration response signals can be denoised, filtered, normalized in amplitude, and screened for consistency of repeated excitations.

[0044] After acquiring the vibration response signal, feature extraction is performed on the vibration response signal corresponding to each shock wave propagation path. The signal features include at least one of the following: shock wave arrival time, response amplitude, amplitude attenuation degree, dominant frequency change, phase change, arrival order change, symmetry path difference, and high-frequency envelope abrupt change.

[0045] The aforementioned signal characteristics are compared with health baseline signals, historical detection signals, signals from symmetrical regions within the same tower, or theoretical propagation responses. When the arrival time of the shock wave relative to the health baseline signal is delayed by more than a preset time difference threshold, or the response amplitude attenuation exceeds a preset amplitude difference threshold, or the dominant frequency shift exceeds a preset frequency difference threshold, or the phase difference exceeds a preset phase difference threshold, or the high-frequency envelope abrupt change exceeds a preset envelope abrupt change threshold, the corresponding propagation path can be identified as an abnormal propagation path. When at least two signal characteristics simultaneously exceed their corresponding abnormal thresholds, or any signal characteristic exceeds its corresponding strong abnormal threshold, the corresponding shock wave propagation path is identified as meeting a preset strong abnormal condition.

[0046] S5: Determine the target's vulnerable areas based on the path coverage matrix and anomaly propagation paths; After determining the abnormal propagation path, the target loosening area is determined based on the propagation path binding relationship between the abnormal propagation path and the first candidate loosening area.

[0047] Based on the abnormal path association table, the number of times each first candidate loosening region is bound to an abnormal propagation path, the minimum topological distance between each abnormal propagation path, the historical correction status, whether it is located on the main load transfer path, and whether there is an abnormal structural symmetry path are counted.

[0048] When two or more abnormal propagation paths are bound to the same first candidate loosening region, and the topological distance between the region and each abnormal propagation path is not greater than a preset distance threshold, the first candidate loosening region is determined as the target loosening region.

[0049] When multiple first candidate loosening regions meet the above conditions, they are sorted in the following order: the number of times the abnormal propagation path is bound is greater than the number of times, the minimum topological distance is greater than the number of times, the region located on the main load transmission path is given priority, and the region with the abnormality of the structural symmetry path is given priority. The first candidate loosening region ranked first is determined as the target loosening region.

[0050] When an anomaly propagation path binds multiple first-candidate loosening regions, these regions are sorted in ascending order of topological distance, and the first-ranked first-candidate loosening region is determined as the target loosening region. If multiple first-candidate loosening regions exist with the same topological distance and are ranked highest, the first-ranked first-candidate loosening region with a historical correction state of enhancement is selected as the target loosening region. If multiple first-candidate loosening regions exist with the same topological distance and all have historical correction states of enhancement, the first-ranked first-candidate loosening region located on the main load transfer path is selected as the target loosening region.

[0051] If the target loose area still cannot be uniquely determined after the above sorting, then all the first candidate loose areas will be marked as areas to be reviewed.

[0052] S6: Obtain the on-site verification results of the target easily loosened area and update the historical correction status of the corresponding bolt group area.

[0053] After identifying the target area prone to loosening, the basic code corresponding to the target area is matched with the spatial coordinates in the 3D spatial positioning model to generate a spatial positioning code. The spatial positioning code includes the tower number, height layer number, member number, node number, orientation side number, connecting plate number, and bolt group number, generated in the order of tower number, height layer number, member number, node number, orientation side number, connecting plate number, and bolt group number. Each bolt group area within the same transmission tower corresponds to a unique spatial positioning code.

[0054] Once the target loose area is identified, the on-site verification or retightening results for that area can be obtained. On-site verification results can be obtained through manual visual inspection, torque wrench testing, inspection of nut relative displacement marks, image verification, or retightening operation records. The retightening results must include at least the torque before and after retightening. When the torque before retightening is lower than a preset torque threshold, or the difference between the torques before and after retightening exceeds a preset torque difference threshold, the area of ​​that bolt group is recorded as having a loosening confirmed result.

[0055] Using the spatial location code of the target easily loosened area as an index field, the above-mentioned on-site verification results or tightening results are written into the historical inspection record and tightening record. During subsequent identification, the historical correction status of the corresponding bolt group area is updated according to the historical inspection record and tightening record corresponding to the spatial location code, and the identification rules of the corresponding bolt group area are updated according to the updated historical correction status.

[0056] It should be noted that in this invention, the preset conditions, preset thresholds, preset levels, preset times, preset distances, preset ratios, and high / low judgment rules can be set based on transmission line operation regulations, tower design parameters, construction and acceptance data, historical testing data of transmission towers of the same model, testing data of symmetrical areas of the same transmission tower structure, manual calibration data, or a combination of the above data. The preset conditions and preset thresholds are not limited to fixed values; they can be adjusted based on tower type, line section, wind zone level, terrain conditions, pole material, testing equipment model, excitation method, and historical maintenance records.

[0057] In one embodiment of the present invention, a positioning system for easily loosened areas of transmission tower bolts is provided, applied to the method described above, including: Modeling and Partitioning Module: Establish a structural topology model of the transmission tower, and divide the transmission tower into multiple bolt group areas based on the structural topology model; First candidate loosening area acquisition module: Based on the pre-acquired wind load parameters, conductor tension parameters, tower type parameters and member connection parameters, determine the load transfer path and structural response of each bolt group area. Combined with the historical correction state setting conditions of each bolt group area, the bolt group area that meets the setting conditions is determined as the first candidate loosening area. Abnormal propagation path acquisition module: Determine the excitation point and detection point on the transmission tower, establish the shock wave propagation path, and bind the shock wave propagation path with the first candidate loose area to form a path coverage matrix; apply shock excitation at the excitation point, collect response signals at the detection point, extract the features of the response signals and compare them with the health benchmark signal to determine the abnormal propagation path; The results output and update module determines the target loose area based on the path coverage matrix and the anomaly propagation path; obtains the on-site verification results of the target loose area, and updates the historical correction status of the corresponding bolt group area.

[0058] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0059] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical functional division. In actual implementation, there may be other division methods, such as multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored.

[0060] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0061] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for locating easily loosened areas of bolts on power transmission towers, characterized in that, Includes the following steps: A structural topology model of the transmission tower is established, and the transmission tower is divided into multiple bolt group areas based on the structural topology model; Based on the wind load parameters, conductor tension parameters, tower type parameters and member connection parameters obtained in advance, the load transfer path and structural response of each bolt group area are determined. Combined with the historical correction state setting conditions of each bolt group area, the bolt group area that meets the setting conditions is determined as the first candidate easy loosening area. Determine the excitation point and detection point on the transmission tower, establish the shock wave propagation path, and bind the shock wave propagation path with the first candidate loose area to form a path coverage matrix; An impact excitation is applied at the excitation point, and a response signal is collected at the detection point. The features of the response signal are extracted and compared with a reference signal to determine the abnormal propagation path. The target vulnerable areas are determined based on the path coverage matrix and abnormal propagation paths; Obtain the on-site verification results of the target easily loosened area and update the historical correction status of the corresponding bolt group area.

2. The method for locating easily loosened areas of transmission tower bolts according to claim 1, characterized in that, The structural topology model includes topological nodes, topological edges, and node attributes. Topological nodes correspond to tower material connection positions, node plate positions, conductor hanging point positions, or ground wire bracket connection positions. Topological edges correspond to main members, diagonal members, crossarms, or other members. Node attributes include at least the height level, orientation side, connection plate number, member type, and number of bolts.

3. The method for locating easily loosened areas of transmission tower bolts according to claim 2, characterized in that, Based on topological nodes, topological edges, and connecting plates, the bolt group regions of the transmission towers are divided into multiple bolt group regions, including one or more non-conflicting classification methods as follows: Prioritize grouping multiple bolts on the same connecting plate into the same bolt group area; When multiple members are connected to the same connecting plate at the same time, the bolts on the connecting plate are further divided into multiple bolt group areas according to the connection direction of the members. When different topological nodes are connected to the two ends of the same member, the bolts at both ends of the member are divided into different bolt group regions. When multiple bolts are located on the same main load transmission path, and the spatial distance between adjacent bolt groups is less than the preset merging distance, the multiple bolts are divided into the same bolt group area.

4. The method for locating easily loosened areas of transmission tower bolts according to claim 1, characterized in that, The first candidate easily loosened areas were identified, including: The load transfer path is determined, which includes the tension transfer path, the wind load transfer path, and the self-weight transfer path. Specifically, the tension transfer path is obtained based on the conductor tension parameters, tower type parameters, and member connection parameters; the wind load transfer path is obtained based on the wind load parameters, tower type parameters, and member connection parameters; and the self-weight transfer path is obtained based on the tower type parameters and member connection parameters. Calculate the structural response, which includes the tower material stress, nodal displacement, member vibration response, load transfer state, and response difference with the symmetrical region of the structure corresponding to each bolt group region; The filtering conditions are set, including structural location conditions, load path conditions, and structural response conditions. The structural location condition is that the bolt group area is located in at least one pre-defined structural location. The load path condition is that the bolt group area is located on at least one path of tension transmission path, wind load transmission path, and self-weight transmission path. The structural response condition is to compare the structural response of each bolt group area with the corresponding reference object. When any structural response exceeds the corresponding anomaly threshold, the bolt group area is determined to meet the structural response condition. Obtain historical correction states, which include enhanced states, maintained states, and suppressed states; Determine the region to be screened: Compare each bolt group region with the structural location condition, load path condition, and structural response condition. If any bolt group region satisfies the structural response condition and at least one of the structural location condition or load path condition, then the bolt group region is determined as the region to be screened. If any bolt group region has a historical correction state that is an enhanced state and satisfies at least one of the structural location condition or load path condition, then the bolt group region is also determined as the region to be screened. Identifying the first candidate loosening region: The region to be screened is further screened based on its historical correction status. When the historical correction status of the region to be screened is an enhanced state or a maintained state, the region to be screened is identified as the first candidate loosening region. When the historical correction status of the region to be screened is an inhibited state, the region to be screened is identified as the first candidate loosening region only if it meets the preset strong response conditions. The preset strong response conditions include the bolt group region meeting the response anomaly conditions under two or more wind direction conditions, or the response difference between the bolt group region and its structural symmetrical region meeting the preset inconsistency conditions, or the bolt group region being located at both the tower section change position and the main load transmission path, or the historical re-tightening torque change record of the bolt group region meeting the preset torque change conditions.

5. The method for locating easily loosened areas of transmission tower bolts according to claim 1, characterized in that, The path coverage matrix records the shock wave propagation path corresponding to each set of excitation points and detection points, as well as the coverage relationship between the shock wave propagation path and the first candidate easily loosened area. The coverage relationship includes whether it passes through, whether it is adjacent, topological distance, and whether it is the main propagation path or the auxiliary propagation path. If no propagation path passes through or is adjacent to the current first candidate easily loosened area, an auxiliary detection point or auxiliary excitation point is reselected and the matrix is ​​updated.

6. A method for locating easily loosened areas of transmission tower bolts according to claim 5, characterized in that, Identify the abnormal propagation path, including: Search for at least one topological path from the excitation point to the detection point in the structural topology model, and record the topological nodes, topological edges and connecting plates passed through as the shock wave propagation path. When the first candidate loose area is located on the propagation path, or its topological distance is not greater than the preset adjacent distance threshold, the area is bound to the propagation path. There is one main propagation path and at least one auxiliary propagation path between the same excitation point and the detection point. An impact excitation is applied, a response signal is acquired, and signal features are extracted. The signal features include the arrival time of the shock wave, the response amplitude, the amplitude attenuation degree, the main frequency change, the phase change, and the high-frequency envelope abrupt change. The signal characteristics are compared with the signal characteristics of a reference signal, which can be a health benchmark signal, a historical detection signal, a signal from a symmetrical region on the same tower, or a theoretical propagation response. When the arrival time delay of the shock wave exceeds a preset time difference threshold, the response amplitude attenuation exceeds a preset amplitude difference threshold, the main frequency offset exceeds a preset frequency difference threshold, the phase difference exceeds a preset phase difference threshold, or the high-frequency envelope mutation exceeds a preset envelope mutation threshold, the propagation path is determined to be an abnormal propagation path.

7. A method for locating easily loosened areas of transmission tower bolts according to claim 6, characterized in that, Based on the path coverage matrix and anomaly propagation paths, vulnerable areas of the target are identified, including: An abnormal path association table is constructed, which is used to record the number of times each first candidate loosening region is bound by an abnormal propagation path, the minimum topological distance between each abnormal propagation path, the historical correction status, whether it is located on the main load transmission path, and whether there is an abnormal propagation path with structural symmetry. Determine the target's easily loosened area based on any one or more of the following rules: When two or more abnormal propagation paths are bound to the same first candidate loosening region, and the topological distance between the region and each abnormal propagation path is not greater than a preset distance threshold, the first candidate loosening region is determined as the target loosening region. When multiple first candidate loosening regions meet the above conditions, they are sorted in the following order: the number of bindings along the abnormal propagation path from most to least, the minimum topological distance from smallest to largest, and priority is given to regions located on the main load transfer path or those with structural symmetry paths. The first candidate loosening region ranked first is then determined as the target loosening region. When an abnormal propagation path binds multiple first-candidate loosening regions, they are sorted in ascending order of topological distance, and the region ranked first is determined as the target loosening region; if there are multiple regions ranked first and with the same topological distance, the region with a historical correction state of enhanced state is selected first, and the region located on the main load transmission path is selected second. When the topological distance is the same, the historical correction status is the same, and all regions are located or not located on the main load transfer path, multiple regions are marked as regions to be reviewed.

8. A positioning system for easily loosened areas of transmission tower bolts, characterized in that, The method applied to any one of claims 1 to 7 includes: Modeling and Partitioning Module: Establish a structural topology model of the transmission tower, and divide the transmission tower into multiple bolt group areas based on the structural topology model; First candidate loosening area acquisition module: Based on the pre-acquired wind load parameters, conductor tension parameters, tower type parameters and member connection parameters, determine the load transfer path and structural response of each bolt group area. Combined with the historical correction state setting conditions of each bolt group area, the bolt group area that meets the setting conditions is determined as the first candidate loosening area. Abnormal propagation path acquisition module: Determine the excitation point and detection point on the transmission tower, establish the shock wave propagation path, and bind the shock wave propagation path with the first candidate loose area to form a path coverage matrix; apply shock excitation at the excitation point, collect response signals at the detection point, extract the features of the response signals and compare them with the health benchmark signal to determine the abnormal propagation path; The results output and update module determines the target loose area based on the path coverage matrix and the anomaly propagation path; obtains the on-site verification results of the target loose area, and updates the historical correction status of the corresponding bolt group area.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the method for locating easily loosened areas of transmission tower bolts as described in any one of claims 1 to 7.

10. A processor, characterized in that, The processor is used to run a program, wherein the program executes the method for locating easily loosened areas of transmission tower bolts as described in any one of claims 1 to 7.

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