A method and system for evaluating performance of a conductor after a wildfire fault, and a medium

Abstract

A method, system, and medium for evaluating the performance of conductors after a wildfire failure are disclosed. The method includes: inputting images and parameter information of the conductor to be evaluated into a pre-trained appearance evaluation model to perform a preliminary assessment of the damage level; if the preliminary assessment result indicates non-severe damage, performing a secondary assessment of the damage level based on the conductor's diameter and standard requirements; if the secondary assessment result indicates non-severe damage, conducting a tensile strength test to obtain the tensile strength, and performing a tertiary assessment of the damage level based on the tensile strength; if the tertiary assessment result indicates non-severe damage, obtaining the recrystallization status of the conductor's microstructure, and performing a quaternary assessment of the damage level based on the recrystallization status; and determining the damage grade of the conductor based on the assessment results of the preliminary, secondary, tertiary, and quaternary assessments. This application enables rapid, convenient, and accurate evaluation of conductor performance after a wildfire failure, while effectively guiding subsequent operation and maintenance work.

Description

Technical Field

[0001] This application belongs to the field of power transmission line conductor technology, specifically relating to a method, system and medium for evaluating conductor performance after a wildfire fault. Background Technology

[0002] Overhead transmission lines are a crucial physical carrier for energy allocation and power supply in the new power system. As the new power system becomes a new engine, long transmission distances and large spatial spans have become significant characteristics of overhead transmission lines. This has led to more complex and variable operating conditions for these lines, with a marked increase in the proportion of lines passing through mountainous and forest-prone fire-prone areas. In the spring of 2014, affected by wildfires, 47 220kV and above lines experienced emergency shutdowns, 17 were operated at reduced voltage, and 213 were disconnected from reclosing. Wildfires have become one of the major natural disasters causing transmission line failures.

[0003] Forest fires in high-temperature or dry climates spread rapidly, burn at high temperatures, and last for extended periods. The highest temperature at the flame center can reach 1200℃, the highest temperature at the boundary can reach 1100℃, and the temperature of hot smoke can exceed 520℃. The flame column height can reach 20-30 meters. Overhead power transmission line conductors are mostly made of aluminum alloy stranded wire, steel-cored aluminum stranded wire, and aluminum-clad steel stranded wire, with the outer layer primarily composed of aluminum, aluminum alloy, and steel wire. Under high-temperature fire conditions, these materials are prone to softening and strength reduction, which can lead to severe line breakage. Post-fire evaluation of conductor performance is crucial; substandard conductors must be replaced, while those that still meet usage requirements require regular maintenance.

[0004] Currently, the inspection of power transmission lines after wildfires includes macroscopic inspection, laboratory mechanical property analysis, and microstructural analysis. Macroscopic inspection to assess the condition of transmission line conductors relies primarily on the operational experience of line workers, which is somewhat arbitrary and unreliable, lacking a clear classification of damage levels and offering limited guidance to on-site workers. While laboratory microscopic and mechanical property analyses using sophisticated instruments can accurately assess the performance of conductors after wildfires, in practice, this requires on-site sampling and resampling, resulting in a massive workload and a long timeframe. Summary of the Invention

[0005] To address the problems of existing methods for testing conductor performance after wildfires, such as lack of standardization, objectivity, large workload, and long cycle, this application provides a method for evaluating conductor performance after wildfires, including: The image and parameter information of the conductor to be evaluated are input into a pre-trained appearance evaluation model to conduct a preliminary assessment of the degree of damage to the conductor. When the initial assessment results indicate that the damage level is mild or moderate, a secondary assessment of the damage degree is conducted based on the diameter of the conductor to be evaluated and the standard requirement value. When the damage level of the secondary assessment result is mild or moderate damage, the tensile strength test is performed on the conductor to be evaluated to obtain the tensile strength, and the degree of damage is assessed three times based on the tensile strength. When the damage level of the three assessments is mild or moderate, the recrystallization of the microstructure of the conductor to be evaluated is obtained by optical microscopy or scanning electron microscopy, and the degree of damage is assessed four times based on the recrystallization. The damage level of the conductor to be evaluated is determined based on the evaluation results of the preliminary assessment, secondary assessment, tertiary assessment and quaternary assessment. The pre-trained appearance evaluation model is obtained by training a deep neural network with training samples constructed from historical images of wildfire conductors, parameter information, and labeled loss levels.

[0006] Preferably, the training of the appearance evaluation model includes: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

[0007] Preferably, the secondary assessment of the damage degree based on the diameter of the conductor to be evaluated and the standard requirement value includes: When the diameter of the conductor to be evaluated is equal to the standard requirement value, the conductor to be evaluated is considered to have minor damage. When the diameter of the conductor to be evaluated is greater than the standard requirement value of the set ratio but less than the standard requirement value, the conductor to be evaluated is moderately damaged. When the diameter of the conductor to be evaluated is less than the standard requirement value of the set ratio, the conductor to be evaluated is severely damaged.

[0008] Preferably, the tensile strength test on the conductor to be evaluated to obtain the tensile strength includes: Multiple single-wire samples were selected from different locations of the conductor to be evaluated; The tensile strength of each selected single-wire sample was tested to obtain the tensile strength of each single-wire sample. The average tensile strength of the selected single-wire samples is taken as the tensile strength value of the conductor to be evaluated.

[0009] Preferably, the step of obtaining the recrystallization status of the microstructure of the wire to be evaluated using an optical microscope or scanning electron microscope includes: One wire is selected from each layer of single wires of the conductor to be evaluated to obtain a sample; The microstructure of the sample is observed using a microscope or scanning electron microscope to determine the recrystallization status; The recrystallization conditions include: no recrystallization, partial recrystallization with significant grain coarsening, and complete recrystallization with severe grain coarsening and grain boundary oxidation.

[0010] Preferably, the three-stage damage assessment based on tensile strength includes: If the tensile strength does not decrease compared to the nominal tensile strength of a single wire of the type of conductor to be evaluated, then the conductor to be evaluated is slightly damaged; otherwise, calculate the difference between the nominal tensile strength and the tensile strength to obtain the decrease in tensile strength. When the decrease in tensile strength exceeds a first set threshold, the conductor to be evaluated is severely damaged. When the decrease in tensile strength is greater than the second set threshold but less than the first set threshold, the conductor to be evaluated is considered to have moderate damage.

[0011] Preferably, the four-stage damage assessment based on recrystallization includes: When the recrystallization of the microstructure is complete recrystallization with severely coarsened grains and oxidized grain boundaries, the conductor to be evaluated is severely damaged. When the recrystallization of the microstructure is partial recrystallization and the grains are significantly coarsened, the conductor to be evaluated is moderately damaged. When no recrystallization occurs in the microstructure, the conductor to be evaluated is considered to have slight damage.

[0012] Preferably, determining the damage level of the conductor to be evaluated based on the evaluation results of the preliminary assessment, secondary assessment, tertiary assessment, and quaternary assessment includes: If the results of the initial assessment, secondary assessment, or tertiary assessment indicate severe damage, the damage level of the conductor to be evaluated is deemed severe damage; otherwise, the results of the fourth assessment will be used as the damage level of the conductor to be evaluated.

[0013] This application also provides a system for evaluating the performance of power lines after a wildfire failure, including: The preliminary assessment module is used to input the image and parameter information of the conductor to be evaluated into a pre-trained appearance assessment model to conduct a preliminary assessment of the damage degree of the conductor to be evaluated. The secondary assessment module is used to conduct a secondary assessment of the degree of damage based on the diameter of the conductor to be evaluated and the standard requirement value when the damage level of the initial assessment result is mild or moderate damage. The strength testing module is used to perform tensile strength testing on the conductor to be evaluated when the damage level of the secondary assessment result is mild or moderate damage, to obtain the tensile strength, and to conduct a third assessment of the damage degree based on the tensile strength. The microscopic testing module is used to obtain the recrystallization status of the microstructure of the wire to be evaluated using an optical microscope or scanning electron microscope when the damage level of the three assessment results is mild or moderate damage, and to conduct four assessments of the degree of damage based on the recrystallization status. The damage assessment module is used to determine the damage level of the conductor to be evaluated based on the assessment results of the preliminary assessment, secondary assessment, tertiary assessment, and quaternary assessment. The pre-trained appearance evaluation model is obtained by training a deep neural network with training samples constructed from historical images of wildfire conductors, parameter information, and labeled loss levels.

[0014] Preferably, it further includes a training module for: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

[0015] Preferably, the secondary evaluation module is specifically used for: When the diameter of the conductor to be evaluated is equal to the standard requirement value, the conductor to be evaluated is considered to have minor damage. When the diameter of the conductor to be evaluated is greater than the standard requirement value of the set ratio but less than the standard requirement value, the conductor to be evaluated is moderately damaged. When the diameter of the conductor to be evaluated is less than the standard requirement value of the set ratio, the conductor to be evaluated is severely damaged.

[0016] Preferably, the set ratio is 85%.

[0017] Preferably, the strength testing module is specifically used for: Multiple single-wire samples were selected from different locations of the conductor to be evaluated; The tensile strength of each selected single-wire sample was tested to obtain the tensile strength of each single-wire sample. The average tensile strength of the selected single-wire samples is taken as the tensile strength value of the conductor to be evaluated. If the tensile strength does not decrease compared to the nominal tensile strength of a single wire of the type of conductor to be evaluated, then the conductor to be evaluated is slightly damaged; otherwise, calculate the difference between the nominal tensile strength and the tensile strength to obtain the decrease in tensile strength. When the decrease in tensile strength exceeds a first set threshold, the conductor to be evaluated is severely damaged. When the decrease in tensile strength is greater than the second set threshold but less than the first set threshold, the conductor to be evaluated is considered to have moderate damage.

[0018] Preferably, the microscopic testing module is specifically used for: One wire is selected from each layer of single wires of the conductor to be evaluated to obtain a sample; The microstructure of the sample is observed using a microscope or scanning electron microscope to determine the recrystallization status; When the recrystallization of the microstructure is complete recrystallization with severely coarsened grains and oxidized grain boundaries, the conductor to be evaluated is severely damaged. When the recrystallization of the microstructure is partial recrystallization and the grains are significantly coarsened, the conductor to be evaluated is moderately damaged. When no recrystallization is observed in the microstructure, the conductor to be evaluated is considered to have minor damage. The recrystallization conditions include: no recrystallization, partial recrystallization with significant grain coarsening, and complete recrystallization with severe grain coarsening and grain boundary oxidation.

[0019] Preferably, the rating assessment module is specifically used for: If the results of the initial assessment, secondary assessment, or tertiary assessment indicate severe damage, the damage level of the conductor to be evaluated is deemed severe damage; otherwise, the results of the fourth assessment will be used as the damage level of the conductor to be evaluated.

[0020] This application also provides an electronic device, comprising: at least one processor and a memory; the memory and the processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, the method for evaluating the performance of power lines after a wildfire failure is implemented.

[0021] This application also provides a readable storage medium having an executable program stored thereon, which, when executed, implements the aforementioned method for evaluating the performance of power lines after a wildfire failure.

[0022] Compared with the prior art, the beneficial effects of this application are as follows: This application proposes a method for evaluating the performance of conductors after wildfire failures, comprising: inputting images and parameter information of the conductor to be evaluated into a pre-trained appearance evaluation model to perform a preliminary assessment of the damage level of the conductor; when the damage level of the preliminary assessment result is mild or moderate damage, performing a secondary assessment of the damage level based on the diameter of the conductor and the standard requirement value; when the damage level of the secondary assessment result is mild or moderate damage, performing a tensile strength test on the conductor to obtain the tensile strength, and performing a tertiary assessment of the damage level based on the tensile strength; when the damage level of the tertiary assessment result is mild or moderate damage, using an optical microscope or scanning electron microscope to obtain the recrystallization of the microstructure of the conductor to be evaluated, and performing a quaternary assessment of the damage level based on the recrystallization; and determining the damage level of the conductor based on the assessment results of the preliminary, secondary, tertiary, and quaternary assessments; wherein, the pre-trained appearance evaluation model is obtained by training a deep neural network using training samples constructed from historical images and parameter information of the conductor after wildfires, as well as labeled loss levels. This application employs a series of assessments—preliminary, secondary, tertiary, and quaternary—to progressively evaluate the damage level. The assessment concludes when the damage is classified as severe. This approach enables a rapid, convenient, and accurate evaluation of conductor performance after a wildfire. Furthermore, this application assesses conductor performance based on appearance, changes in conductor diameter, tensile strength testing, and microstructure changes. It provides a standardized and objective method for evaluating conductor performance after a wildfire, addressing the issues of non-standardization, lack of objectivity, and excessive workload associated with existing testing methods. It also effectively guides subsequent maintenance and repair work. Attached Figure Description

[0023] Figure 1 This is a flowchart of a method for evaluating the performance of power lines after a wildfire failure, as described in this application. Figure 2 This is a schematic diagram of maintenance schemes corresponding to different degrees of damage in this application; Figure 3The appearance of the conductor after a wildfire in Embodiment 2 of this application; Figure 4 The appearance of the conductor after the wildfire in Embodiment 3 of this application; Figure 5 This is a schematic diagram of the topology of the electronic device of this application. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other instances that are improved or modified by those skilled in the art are within the scope of protection of this application. It should be understood that the embodiments of this application are only used to illustrate the technical effects of this application, and are not intended to limit the scope of protection of this application. Unless otherwise specified, the methods used in the embodiments are conventional methods.

[0025] Example 1 This embodiment provides a method for evaluating the performance of power lines after a wildfire failure, such as... Figure 1 As shown, it includes: S1. Input the image and parameter information of the conductor to be evaluated into the pre-trained appearance evaluation model to perform a preliminary assessment of the damage degree of the conductor to be evaluated. S2. When the damage level of the initial assessment result is mild or moderate damage, a secondary assessment of the damage degree is conducted based on the diameter of the conductor to be evaluated and the standard requirement value. S3. When the damage level of the secondary assessment result is mild or moderate damage, the tensile strength test is performed on the conductor to be evaluated to obtain the tensile strength, and the degree of damage is assessed three times based on the tensile strength. S4. When the damage level of the three assessment results is mild or moderate, the recrystallization of the microstructure of the conductor to be evaluated is obtained by optical microscopy or scanning electron microscopy, and the degree of damage is assessed four times based on the recrystallization. S5. Determine the damage level of the conductor to be evaluated based on the evaluation results of the preliminary evaluation, secondary evaluation, tertiary evaluation and quaternary evaluation. The pre-trained appearance evaluation model is obtained by training a deep neural network with training samples constructed from historical images of wildfire conductors, parameter information, and labeled loss levels.

[0026] The following section provides further details on each step in this application.

[0027] Before step S1, images and parameter information of the conductor to be evaluated are obtained. Then, the appearance evaluation model involved in this application is introduced. The training process of the appearance evaluation model includes: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

[0028] S1: Input the image and parameter information of the conductor to be evaluated into a pre-trained appearance evaluation model to perform a preliminary assessment of the damage degree of the conductor, including: The image and parameter information of the conductor to be evaluated are input into the trained appearance evaluation model, and the preliminary assessment results of the damage degree of the conductor to be evaluated are output. The preliminary assessment results include: severe injury, moderate injury, and minor injury.

[0029] The preliminary assessment specifically involves evaluating the surface condition and mechanical damage, as detailed below: Indicator 1: Appearance and shape.

[0030] 1) Surface condition The surface of the conductor should be smooth and free from any defects such as cracks, burrs, splits, or inclusions.

[0031] Normal aluminum wires should be white. During a wildfire, the surface of the wire will change color. Initially, the wire will slowly turn black. If the wildfire temperature is high, the blackened outer layer of the wire will gradually disappear, and then it will turn white again. This is because the melting point of pure aluminum is 660.4℃, while the highest temperature at the center of a flame can reach 1200℃, the highest temperature at the edge can reach 1100℃, and the temperature of hot smoke can exceed 520℃. The final whitening is likely due to the melting of the outer aluminum wire caused by the flame temperature.

[0032] Surface condition analysis: Inspect the zinc plating of the conductor (for ACSR steel core or galvanized steel wire, etc.) or the oxidation and melting of the aluminum wire itself. The zinc plating will turn black, peel, or flake off, losing its anti-corrosion function. For aluminum wire, mainly observe the color and whether there is melting, the formation of droplets, or nodules.

[0033] 2) Mechanical damage After a wildfire, uneven heating can cause a decrease in local strength of the conductor, leading to broken strands, cracks, or significant plastic deformation. If obvious broken strands are found, the conductor needs to be replaced immediately.

[0034] This application uses a pre-trained appearance evaluation model to evaluate the surface condition and mechanical damage of the conductor to be evaluated.

[0035] S2. When the initial assessment indicates minor or moderate damage, a secondary assessment of the damage level is conducted based on the diameter of the conductor to be evaluated and the standard requirements, including: When the diameter of the conductor to be evaluated is equal to the standard requirement value, the conductor to be evaluated is considered to have minor damage. When the diameter of the conductor to be evaluated is greater than the standard requirement value of the set ratio but less than the standard requirement value, the conductor to be evaluated is moderately damaged. When the diameter of the conductor to be evaluated is less than the standard requirement value of the set ratio, the conductor to be evaluated is severely damaged.

[0036] The specific implementation steps of step S2 include: Indicator 2: Wire diameter Uneven heating can cause conductors to twist, bulge, or experience localized changes in diameter, which in turn can alter the diameter of the conductors and individual wires. For example, bulging or loose strands can lead to an increase in the diameter of the stranded wire. For galvanized steel cores and aluminum wires, localized stretching can also cause diameter changes.

[0037] The key parameter is the diameter of the single wire. The diameter of the single wire after a wildfire is measured using vernier calipers. If the diameter of the single wire after a wildfire still meets the requirements of the relevant standards (GB / T 1179, GB / T20141, etc.), it indicates that the wire has suffered minor damage. If the diameter of the single wire after a wildfire is greater than 85% of the standard requirement but less than the standard requirement, it indicates that the wire has suffered moderate damage. If the diameter of the single wire after a wildfire is less than 85% of the standard requirement, it indicates that the wire has suffered severe damage.

[0038] S3: When the damage level of the secondary assessment result is mild or moderate damage, a tensile strength test is performed on the conductor to be evaluated to obtain the tensile strength, and the degree of damage is assessed three times based on the tensile strength, including: Multiple single-wire samples were selected from different locations of the conductor to be evaluated; Tensile strength tests were performed on the selected single-wire samples to obtain the tensile strength of each single-wire sample. The average tensile strength of the selected single-wire samples is taken as the tensile strength value of the conductor to be evaluated. If the tensile strength does not decrease compared to the nominal tensile strength of a single wire of the type of conductor to be evaluated, then the conductor to be evaluated is slightly damaged; otherwise, calculate the difference between the nominal tensile strength and the tensile strength to obtain the decrease in tensile strength. When the decrease in tensile strength exceeds a first set threshold, the conductor to be evaluated is severely damaged. When the decrease in tensile strength is greater than the second set threshold but less than the first set threshold, the conductor to be evaluated is considered to have moderate damage.

[0039] Specifically, the calculation process for index three, tensile strength, will be described in detail below.

[0040] Tensile strength can quickly assess the degree of annealing softening in conductors due to overheating. Obtaining the tensile strength index includes: selecting several single-wire samples from different locations of the conductor to be evaluated for tensile strength testing; calculating the average tensile strength value of the single-wire samples; comparing the average tensile strength value with the nominal tensile strength value of the corresponding single wire, and using the percentage decrease as the quantitative result of the tensile strength index. Tensile strength testing is performed on single wires of conductors that have experienced wildfires to evaluate the retention rate of the conductor's mechanical properties after the wildfire. A universal tensile testing machine is used as the testing equipment.

[0041] As a specific implementation method of this embodiment, 3 to 10 single-wire samples are selected at different locations of the conductor (especially the lowest point of sag and the suspension point), preferably 5 single-wire samples, for tensile strength testing. The average tensile strength of the selected samples is calculated as the tensile strength value of the single wire. The measured value of the single wire after the wildfire failure is compared with the nominal tensile strength value of the single wire (GB / T 1179, GB / T20141, etc.). The decrease in tensile strength is direct evidence that the conductor has experienced high temperatures.

[0042] Compared with the nominal tensile strength value of the single wire of this model, if the tensile strength does not decrease, the wire is judged to be slightly damaged. If the decrease in tensile strength is less than the set strength threshold, the wire is judged to be moderately damaged. If the decrease in tensile strength is greater than or equal to the set strength threshold, the wire is judged to be severely damaged. In this embodiment, the set strength threshold can be set according to experience or according to relevant standards. In this embodiment, the set strength threshold is 15%.

[0043] S4: When the damage level determined by the three assessments is mild or moderate, the recrystallization of the microstructure of the lead under evaluation is obtained using an optical microscope or scanning electron microscope. Based on the recrystallization, the degree of damage is assessed four times, including: One wire is selected from each layer of single wires of the conductor to be evaluated to obtain a sample; The microstructure of the sample is observed using a microscope or scanning electron microscope to determine the recrystallization status; When the recrystallization of the microstructure is complete recrystallization with severely coarsened grains and oxidized grain boundaries, the conductor to be evaluated is severely damaged. When the recrystallization of the microstructure is partial recrystallization and the grains are significantly coarsened, the conductor to be evaluated is moderately damaged. When no recrystallization is observed in the microstructure, the conductor to be evaluated is considered to have minor damage. The recrystallization conditions include: no recrystallization, partial recrystallization with significant grain coarsening, and complete recrystallization with severe grain coarsening and grain boundary oxidation.

[0044] The following section provides a detailed introduction to the acquisition process of Indicator 4: Microorganisms.

[0045] Microstructure is key to explaining the degradation of conductor performance. Single wires are typically produced through a drawing process, which involves work hardening and forms a fibrous structure. The high temperatures of wildfires significantly coarsen the grains, further leading to a decrease in strength and hardness.

[0046] The acquisition of the microstructure index includes: taking a sample from a single wire of the conductor to be evaluated; observing the microstructure of the sample; and determining the microstructure index based on the grain morphology, degree of recrystallization, and grain boundary state.

[0047] As a specific implementation method of this embodiment, the selection of samples for microstructure analysis can involve taking one wire from each layer and simultaneously selecting one wire of the same type that has not experienced a wildfire for comparison. The samples are ground and polished, and then the structure is displayed using a suitable chemical or electrolytic etching agent. The microstructure of the wire is observed using an optical microscope or a scanning electron microscope (SEM), and the performance changes of the wire after experiencing a wildfire are determined by the recrystallization.

[0048] Compared to the microstructure samples of single-wire conductors that have not experienced wildfires, the conductors that did not show recrystallization after the wildfires are considered to have only minor damage and require enhanced monitoring; they can continue to operate. Some recrystallization, with a recrystallization rate of less than 5%, indicates moderate damage and requires replacement. Risk assessment and reduced load operation are necessary. A recrystallization rate of 5% or higher indicates severe damage and requires immediate replacement, posing a high risk.

[0049] S5: Based on the assessment results of the preliminary assessment, secondary assessment, tertiary assessment, and quaternary assessment, determine the damage level of the conductor to be evaluated, including: If the results of the initial assessment, secondary assessment, or tertiary assessment indicate severe damage, the damage level of the conductor to be evaluated is deemed severe damage; otherwise, the results of the fourth assessment will be used as the damage level of the conductor to be evaluated.

[0050] The following section will provide a further explanation of step S5.

[0051] Determining the damage level of the conductor to be evaluated on at least two evaluation indicators specifically includes: presetting a judgment threshold corresponding to the damage level for each evaluation indicator; for the appearance and morphology indicators, the judgment threshold includes: the type and severity of surface defects, the rate of change of geometric dimensions, and the type of mechanical damage; for the diameter indicator, the judgment threshold is: a standard requirement value of a set proportion; for the tensile strength indicator, the judgment threshold is the percentage decrease in tensile strength; for the microstructure indicator, the judgment threshold includes the degree of grain growth, the recrystallization ratio, and the degree of grain boundary oxidation.

[0052] The judgment thresholds include: a decrease in tensile strength of less than 10% corresponds to mild damage, a decrease of 10% to 30% corresponds to moderate damage, and a decrease of more than 30% corresponds to severe damage; and / or, a change in geometric dimensions of less than 15% corresponds to moderate damage, and a change range of more than or equal to 15% corresponds to severe damage.

[0053] The principle for determining the damage level of the conductor to be evaluated is as follows: if the damage level of any evaluation indicator reaches severe damage, the performance evaluation result is high risk, and the recommended maintenance measure is immediate replacement; if the damage level of all evaluation indicators is mild damage, the performance evaluation result is low risk, and the recommended maintenance measure is to strengthen monitoring and continue operation; in other cases, the performance evaluation result is moderate risk, and the recommended maintenance measure is planned replacement and assessment of load reduction operation.

[0054] The steps for evaluating the performance of power lines after a wildfire are as follows: 1) Analysis of conductor appearance and morphology: Select typical conductors after the wildfire and observe their surface condition. If the surface is slightly discolored and the galvanized layer is slightly oxidized without mechanical damage, the conductor is initially judged to be slightly damaged. If the galvanized layer is partially damaged, the aluminum wire is discolored, and there are slight cracks, the conductor is initially judged to be moderately damaged. If the galvanized layer is completely destroyed, the aluminum wire melts and forms droplets or nodules, and there are broken wires, broken strands, and obvious bulges, the conductor is judged to be severely damaged and should be replaced immediately.

[0055] 2) Conductor diameter inspection: Based on the surface condition, the conductor is determined to be slightly or moderately damaged. In addition, the diameter of each individual conductor needs to be inspected. The preferred method for inspecting the diameter of an individual conductor is to use a micrometer to measure it. At least three different locations are selected for each individual conductor, and measurements are taken in two mutually perpendicular directions. The average value is then taken as the final diameter of the individual conductor.

[0056] 3) When the diameter of a single line after a wildfire is greater than 85% of the value required by the standard (GB / T 1179, GB / T20141, etc.), it is considered a minor or moderate damage.

[0057] 4) When the diameter of a single wire after a wildfire is less than or equal to 85% of the standard requirement, it indicates that the wire is severely damaged and needs to be replaced immediately.

[0058] 5) For conductors whose diameter after the wildfire is greater than 85% of the standard requirement, a single-wire tensile strength test is required.

[0059] 6) The tensile strength test of a single wire is performed using a universal testing machine. 3 to 10 single wires are selected for each conductor, preferably 5 single wires.

[0060] 7) If the tensile strength of a single wire does not decrease relative to the nominal tensile strength of the single wire (GB / T 1179, GB / T20141, etc.) after a wildfire, it is considered minor damage and further microstructural analysis is required.

[0061] 8) If the strength of a single conductor decreases by 0 to 15% after a wildfire, it is considered moderately damaged and should be replaced. Risk assessment and reduced load operation are required.

[0062] 9) If the single-wire strength of a conductor decreases by more than 15% after a wildfire, the conductor is considered severely damaged and needs to be replaced immediately.

[0063] 10) Further microstructural analysis should be performed on the conductors from step 6). One conductor from each layer should be sampled, and one conductor of the same type that has not experienced wildfires should be selected for comparison. The recrystallization rate can be manually calculated using image analysis software (such as Image-Pro Plus, ImageJ) or the intercept / area method, with image analysis software being preferred. Further processing should be performed based on the following: No recrystallization was observed, indicating minor damage. Closer monitoring is required, but operation can continue. Partial recrystallization, with a recrystallization rate of less than 5%, indicates moderate damage. Replacement is planned, but risk assessment and reduced load operation are required. A recrystallization rate greater than 5% indicates severe damage, requiring immediate replacement and posing a high risk.

[0064] The specific judgment indicators are shown in Table 1.

[0065] Table 1 Evaluation of Power Wire Performance After Wildfire

[0066] The technical solution of this application can accurately determine the remaining carrying capacity of conductors, providing a basis for decision-making for the safe operation of the power grid and avoiding resource waste or safety accidents caused by misjudgment.

[0067] like Figure 3 The image shows a power line damaged after a wildfire. The wire is broken, with broken strands, appearing as loose strands, and its surface is grayish-black and dirty. According to... Figure 2 The diagrams showing different levels of damage and corresponding maintenance solutions indicate that the wire needs to be replaced immediately.

[0068] Example 2 This example describes a galvanized steel wire used in response to a wildfire, and its evaluation method includes: (1) Appearance and morphology like Figure 4 No obvious defects such as broken wires or strands were observed on the surface of the galvanized steel wire, but rust and coating damage were common.

[0069] The diameter of the galvanized steel wire was measured. The actual diameter of the wire rope with a nominal diameter of 21.5 mm was approximately 20.81 mm, which is about 2.84% less than the nominal diameter. According to Table 1, the galvanized steel wire is moderately damaged.

[0070] This embodiment uses images and parameter information of the conductor to be evaluated, and employs a pre-trained appearance assessment model to perform a preliminary assessment of the degree of damage to the conductor. This pre-trained appearance assessment model is obtained by training a deep neural network with training samples constructed from historical images and parameter information of the conductor after wildfires, as well as labeled loss levels.

[0071] The training of the appearance evaluation model includes: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

[0072] (2) Wire diameter A secondary assessment of the damage level is conducted based on the diameter of the conductor to be evaluated and the standard requirement value, including: When the diameter of the conductor to be evaluated is equal to the standard requirement value, the conductor to be evaluated is considered to have minor damage. When the diameter of the conductor to be evaluated is greater than the standard requirement value of the set ratio but less than the standard requirement value, the conductor to be evaluated is moderately damaged. When the diameter of the conductor to be evaluated is less than the standard requirement value of the set ratio, the conductor to be evaluated is severely damaged.

[0073] (2) Tensile strength A portable hardness tester was used to test the tensile strength of several single wire samples of the outer layer of galvanized steel wire. In this embodiment, five wire samples were selected as an example for tensile strength testing. The results are shown in Table 2. The nominal tensile strength of the galvanized steel wire is 1770 MPa, and the average measured tensile strength is approximately 936 MPa, representing a strength reduction of about 47.12%. Figure 2 It is clear that the wire needs to be replaced immediately.

[0074] Table 2. Tensile strength test results of galvanized steel wire

[0075] Example 3 This embodiment also provides a system for evaluating the performance of power lines after a wildfire failure, including: The preliminary assessment module is used to input the image and parameter information of the conductor to be evaluated into a pre-trained appearance assessment model to conduct a preliminary assessment of the damage degree of the conductor to be evaluated. The secondary assessment module is used to conduct a secondary assessment of the degree of damage based on the diameter of the conductor to be evaluated and the standard requirement value when the damage level of the initial assessment result is mild or moderate damage. The strength testing module is used to perform tensile strength testing on the conductor to be evaluated when the damage level of the secondary assessment result is mild or moderate damage, to obtain the tensile strength, and to conduct a third assessment of the damage degree based on the tensile strength. The microscopic testing module is used to obtain the recrystallization status of the microstructure of the wire to be evaluated using an optical microscope or scanning electron microscope when the damage level of the three assessment results is mild or moderate damage, and to conduct four assessments of the degree of damage based on the recrystallization status. The damage assessment module is used to determine the damage level of the conductor to be evaluated based on the assessment results of the preliminary assessment, secondary assessment, tertiary assessment, and quaternary assessment. The pre-trained appearance evaluation model is obtained by training a deep neural network with training samples constructed from historical images of wildfire conductors, parameter information, and labeled loss levels.

[0076] Preferably, it further includes a training module for: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

[0077] Preferably, the secondary evaluation module is specifically used for: When the diameter of the conductor to be evaluated is equal to the standard requirement value, the conductor to be evaluated is considered to have minor damage. When the diameter of the conductor to be evaluated is greater than the standard requirement value of the set ratio but less than the standard requirement value, the conductor to be evaluated is moderately damaged. When the diameter of the conductor to be evaluated is less than the standard requirement value of the set ratio, the conductor to be evaluated is severely damaged.

[0078] Preferably, the set ratio is 85%.

[0079] Preferably, the strength testing module is specifically used for: Multiple single-wire samples were selected from different locations of the conductor to be evaluated; The tensile strength of each selected single-wire sample was tested to obtain the tensile strength of each single-wire sample. The average tensile strength of the selected single-wire samples is taken as the tensile strength value of the conductor to be evaluated. If the tensile strength does not decrease compared to the nominal tensile strength of a single wire of the type of conductor to be evaluated, then the conductor to be evaluated is slightly damaged; otherwise, calculate the difference between the nominal tensile strength and the tensile strength to obtain the decrease in tensile strength. When the decrease in tensile strength exceeds a first set threshold, the conductor to be evaluated is severely damaged. When the decrease in tensile strength is greater than the second set threshold but less than the first set threshold, the conductor to be evaluated is considered to have moderate damage.

[0080] Preferably, the microscopic testing module is specifically used for: One wire is selected from each layer of single wires of the conductor to be evaluated to obtain a sample; The microstructure of the sample is observed using a microscope or scanning electron microscope to determine the recrystallization status; When the recrystallization of the microstructure is complete recrystallization with severely coarsened grains and oxidized grain boundaries, the conductor to be evaluated is severely damaged. When the recrystallization of the microstructure is partial recrystallization and the grains are significantly coarsened, the conductor to be evaluated is moderately damaged. When no recrystallization is observed in the microstructure, the conductor to be evaluated is considered to have minor damage. The recrystallization conditions include: no recrystallization, partial recrystallization with significant grain coarsening, and complete recrystallization with severe grain coarsening and grain boundary oxidation.

[0081] Preferably, the rating assessment module is specifically used for: If the results of the initial assessment, secondary assessment, or tertiary assessment indicate severe damage, the damage level of the conductor to be evaluated is deemed severe damage; otherwise, the results of the fourth assessment will be used as the damage level of the conductor to be evaluated.

[0082] Example 4 like Figure 5 As shown, this application also provides an electronic device, which may be a computer device, a microcontroller device, a smart mobile device, etc. The electronic device in this embodiment may include a processor, a memory, a transceiver component, etc. The memory, processor, and transceiver component are connected via a bus; the memory can be used to store executable programs, and an exemplary executable program may include instructions; the processor is used to execute the instructions stored in the memory. The memory can also be used to store data, which can be accessed and / or modified when instructions are executed.

[0083] The processor may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and it is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the storage medium to implement the corresponding method flow or corresponding function, so as to realize the steps of the post-wildfire fault conductor performance evaluation method in the above embodiments.

[0084] Example 5 Based on the same inventive concept, this application also provides a readable storage medium, specifically an electronic device readable storage medium (Memory). This readable storage medium is a memory device within an electronic device used to store programs and data. It is understood that the storage medium here can include both built-in storage media within the electronic device and extended storage media supported by the electronic device. The storage medium provides storage space, which stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more executable programs (including program code). It should be noted that the storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. Loading and executing one or more instructions stored in the storage medium by the processor can implement the steps of the post-wildfire conductor performance evaluation method described in the above embodiments.

[0085] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for evaluating the performance of power lines after a wildfire failure, characterized in that, include: The image and parameter information of the conductor to be evaluated are input into a pre-trained appearance evaluation model to conduct a preliminary assessment of the degree of damage to the conductor. When the initial assessment results indicate that the damage level is mild or moderate, a secondary assessment of the damage degree is conducted based on the diameter of the conductor to be evaluated and the standard requirement value. When the damage level of the secondary assessment result is mild or moderate damage, the tensile strength test is performed on the conductor to be evaluated to obtain the tensile strength, and the degree of damage is assessed three times based on the tensile strength. When the damage level of the three assessments is mild or moderate, the recrystallization of the microstructure of the conductor to be evaluated is obtained by optical microscopy or scanning electron microscopy, and the degree of damage is assessed four times based on the recrystallization. The damage level of the conductor to be evaluated is determined based on the evaluation results of the preliminary assessment, secondary assessment, tertiary assessment and quaternary assessment. The pre-trained appearance evaluation model is obtained by training a deep neural network with training samples constructed from historical images of wildfire conductors, parameter information, and labeled loss levels.

2. The method according to claim 1, characterized in that, The training of the appearance evaluation model includes: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

3. The method as described in claim 1, characterized in that, The secondary assessment of damage based on the diameter of the conductor to be evaluated and the standard requirement value includes: When the diameter of the conductor to be evaluated is equal to the standard requirement value, the conductor to be evaluated is considered to have minor damage. When the diameter of the conductor to be evaluated is greater than the standard requirement value of the set ratio but less than the standard requirement value, the conductor to be evaluated is moderately damaged. When the diameter of the conductor to be evaluated is less than the standard requirement value of the set ratio, the conductor to be evaluated is severely damaged.

4. The method as described in claim 1, characterized in that, The tensile strength test of the conductor to be evaluated, to obtain the tensile strength, includes: Multiple single-wire samples were selected from different locations of the conductor to be evaluated; The tensile strength of each selected single-wire sample was tested to obtain the tensile strength of each single-wire sample. The average tensile strength of the selected single-wire samples is taken as the tensile strength value of the conductor to be evaluated.

5. The method as described in claim 1, characterized in that, The recrystallization of the microstructure of the wire to be evaluated, obtained using an optical microscope or scanning electron microscope, includes: One wire is selected from each layer of single wires of the conductor to be evaluated to obtain a sample; The microstructure of the sample is observed using a microscope or scanning electron microscope to determine the recrystallization status; The recrystallization conditions include: no recrystallization, partial recrystallization with significant grain coarsening, and complete recrystallization with severe grain coarsening and grain boundary oxidation.

6. The method as described in claim 1, characterized in that, The three-stage damage assessment based on tensile strength includes: If the tensile strength does not decrease compared to the nominal tensile strength of a single wire of the type of conductor to be evaluated, then the conductor to be evaluated is slightly damaged; otherwise, calculate the difference between the nominal tensile strength and the tensile strength to obtain the decrease in tensile strength. When the decrease in tensile strength exceeds a first set threshold, the conductor to be evaluated is severely damaged. When the decrease in tensile strength is greater than the second set threshold but less than the first set threshold, the conductor to be evaluated is considered to have moderate damage.

7. The method as described in claim 1, characterized in that, The four-stage damage assessment based on recrystallization includes: When the recrystallization of the microstructure is complete recrystallization with severely coarsened grains and oxidized grain boundaries, the conductor to be evaluated is severely damaged. When the recrystallization of the microstructure is partial recrystallization and the grains are significantly coarsened, the conductor to be evaluated is moderately damaged. When no recrystallization occurs in the microstructure, the conductor to be evaluated is considered to have slight damage.

8. The method as described in claim 1, characterized in that, The determination of the damage level of the conductor to be evaluated based on the evaluation results of the preliminary assessment, secondary assessment, tertiary assessment, and quaternary assessment includes: If the results of the initial assessment, secondary assessment, or tertiary assessment indicate severe damage, the damage level of the conductor to be evaluated is deemed severe damage; otherwise, the results of the fourth assessment will be used as the damage level of the conductor to be evaluated.

9. A system for evaluating the performance of power lines after a wildfire failure, characterized in that, include: The preliminary assessment module is used to input the image and parameter information of the conductor to be evaluated into a pre-trained appearance assessment model to conduct a preliminary assessment of the damage degree of the conductor to be evaluated. The secondary assessment module is used to conduct a secondary assessment of the degree of damage based on the diameter of the conductor to be evaluated and the standard requirement value when the damage level of the initial assessment result is mild or moderate damage. The strength testing module is used to perform tensile strength testing on the conductor to be evaluated when the damage level of the secondary assessment result is mild or moderate damage, to obtain the tensile strength, and to conduct a third assessment of the damage degree based on the tensile strength. The microscopic testing module is used to obtain the recrystallization status of the microstructure of the wire to be evaluated using an optical microscope or scanning electron microscope when the damage level of the three assessment results is mild or moderate damage, and to conduct four assessments of the degree of damage based on the recrystallization status. The damage assessment module is used to determine the damage level of the conductor to be evaluated based on the assessment results of the preliminary assessment, secondary assessment, tertiary assessment, and quaternary assessment. The pre-trained appearance evaluation model is obtained by training a deep neural network with training samples constructed from historical images of wildfire conductors, parameter information, and labeled loss levels.

10. The system according to claim 9, characterized in that, It also includes a training module for: Obtain historical images and parameter information of power lines after the wildfire, and mark the damage level. The parameter information includes: geometric dimensions and mechanical damage, and the damage level includes: minor damage, moderate damage and severe damage. A sample set was constructed from historical images, parameter information, and labeled damage levels; The sample set is divided into a training set and a test set according to a set ratio; Using images and parameter information from the training set as input, and damage level as output, a deep neural network is trained to obtain a preliminarily trained appearance evaluation model. The images and parameter information in the test set are input into the pre-trained appearance evaluation model to obtain the damage level evaluation value; Determine whether the damage level assessment value is consistent with the damage level marked in the test set. If they are consistent, the test is passed and the pre-trained appearance assessment model is used as the trained appearance assessment model. Otherwise, determine whether the maximum number of iterations has been reached. If not, continue training the deep neural network based on the training set. Otherwise, end the training.

11. The system as described in claim 9, characterized in that, The strength testing module is specifically used for: Multiple single-wire samples were selected from different locations of the conductor to be evaluated; The tensile strength of each selected single-wire sample was tested to obtain the tensile strength of each single-wire sample. The average tensile strength of the selected single-wire samples is taken as the tensile strength value of the conductor to be evaluated. If the tensile strength does not decrease compared to the nominal tensile strength of a single wire of the type of conductor to be evaluated, then the conductor to be evaluated is slightly damaged; otherwise, calculate the difference between the nominal tensile strength and the tensile strength to obtain the decrease in tensile strength. When the decrease in tensile strength exceeds a first set threshold, the conductor to be evaluated is severely damaged. When the decrease in tensile strength is greater than the second set threshold but less than the first set threshold, the conductor to be evaluated is considered to have moderate damage.

12. The system as described in claim 9, characterized in that, The microscopic testing module is specifically used for: One wire is selected from each layer of single wires of the conductor to be evaluated to obtain a sample; The microstructure of the sample is observed using a microscope or scanning electron microscope to determine the recrystallization status; When the recrystallization of the microstructure is complete recrystallization with severely coarsened grains and oxidized grain boundaries, the conductor to be evaluated is severely damaged. When the recrystallization of the microstructure is partial recrystallization and the grains are significantly coarsened, the conductor to be evaluated is moderately damaged. When no recrystallization is observed in the microstructure, the conductor to be evaluated is considered to have minor damage. The recrystallization conditions include: no recrystallization, partial recrystallization with significant grain coarsening, and complete recrystallization with severe grain coarsening and grain boundary oxidation.

13. The system as described in claim 9, characterized in that, The grade assessment module is specifically used for: If the results of the initial assessment, secondary assessment, or tertiary assessment indicate severe damage, the damage level of the conductor to be evaluated is deemed severe damage; otherwise, the results of the fourth assessment will be used as the damage level of the conductor to be evaluated.

14. An electronic device, characterized in that, include: At least one processor and memory; The memory and processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, a method for evaluating the performance of power lines after a wildfire failure as described in any one of claims 1 to 8 is implemented.

15. A readable storage medium, characterized in that, It contains an execution program, which, when executed, implements a method for evaluating the performance of power lines after a wildfire failure as described in any one of claims 1 to 8.

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