Method for comprehensively evaluating fatigue performance of spacer of power transmission line in natural environment

Abstract

The application discloses a method for comprehensively evaluating fatigue performance of a spacer of a power transmission line in a simulated natural environment, and belongs to the technical field of power transmission line detection. The method comprises the following steps: S10, simulating relevant environments of the spacer, wherein the relevant environments include climate, wind power and vibration; the climate includes environmental temperature, air humidity and sunshine intensity; and S20, setting a monitoring interval based on the climate, wherein the monitoring interval comprises setting changes of the climate with a basic value as a setting target, and the basic value includes an environmental temperature of 0 DEG C. The application can more truly reflect stress conditions and fatigue performance of the spacer in actual operation by simulating conditions such as climate (temperature, humidity and sunshine), wind power and vibration in the natural environment, and can accurately predict crack initiation, an expansion path and fatigue life by analyzing characteristic changes of surface fatigue cracks of the spacer in detail.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission line detection, in particular to a method for comprehensively evaluating the fatigue performance of a spacer of a power transmission line in a simulated natural environment. BACKGROUND

[0002] The spacer of a power transmission line is an important component for fixing the power transmission conductor and preventing the conductors from colliding with each other. In a natural environment, the spacer is long-term affected by wind, temperature changes, vibration and other factors, which can easily cause fatigue damage and affect the safe operation of the power transmission line. Therefore, the fatigue performance of the spacer needs to be evaluated.

[0003] In the technical field of power transmission line detection, there are many methods for evaluating the fatigue performance of power components or auxiliary parts, and the evaluation of the fatigue performance of the spacer is one of them.

[0004] For this research, the application file with the application number CN202210149825.4 provides a method for evaluating the fatigue performance of live working insulating operating poles. The technical solution is as follows: set the working condition, the type of insulating operating pole and the grip distance, carry out pre-test, and determine the optimal target muscle according to the results, collect the bioelectricity signal of the optimal target muscle of each grip distance of each type of insulating operating pole under each working condition, and extract the characteristic value, select the characteristic parameter, establish a fatigue performance evaluation model, label the characteristic parameters according to the muscle state, and establish a training set, and train the fatigue performance evaluation model through the training set. The technical solution can obtain the optimal target muscle through pre-test, evaluate the muscle fatigue according to the surface bioelectricity signal, and effectively improve the detection accuracy and efficiency.

[0005] Another application file with the application number CN202210153226.X provides a method for estimating the fatigue damage of a power transmission line ground wire. The technical solution includes selecting the power transmission line ground wire to be evaluated, combining the S-N characteristic curve of the line and comparing the calculation results with the operation data. The technical solution combines the S-N curve of the ground wire fatigue performance and the OPGW vibration event data feedback of the power transmission line, uses the Miner damage accumulation criterion to evaluate the cumulative fatigue damage and risk of the power transmission line, and scientifically evaluates the service life of the ground wire to provide a decision basis for the operation and maintenance personnel.

[0006] However, the above technical solutions for evaluating the fatigue performance of power components or auxiliary parts are all laboratory static tests, which cannot truly reflect the actual working conditions of power components or auxiliary parts in a natural environment. SUMMARY

[0007] In view of the above problems existing in the existing power transmission line detection technology field, the present application is proposed.

[0008] Therefore, one of the purposes of the present application is to provide a method for comprehensively evaluating fatigue performance of a spacer of a power transmission line in a simulated natural environment, which can more truly reflect the stress condition and fatigue performance of the spacer in actual operation by simulating conditions such as climate (temperature, humidity, sunlight), wind and vibration in the natural environment, and can analyze the characteristic change of the surface fatigue crack of the spacer in detail by means of dynamic load application, strain analysis, numerical simulation (finite element analysis) and the like, so as to accurately predict the initiation, propagation path and fatigue life of the crack.

[0009] To solve the above technical problems, the present application provides the following technical solutions:

[0010] The present application provides a method for comprehensively evaluating fatigue performance of a spacer of a power transmission line in a simulated natural environment, comprising the following steps:

[0011] S10: Simulating relevant environment for the spacer, wherein the relevant environment includes climate, wind and vibration; the climate includes environmental temperature, air humidity and sunlight intensity;

[0012] S20: Setting a monitoring interval based on the climate, wherein the monitoring interval includes setting the change of the climate with one basic value as a setting target, and the basic value includes an environmental temperature of 0℃;

[0013] S30: Synchronously reducing air humidity and sunlight intensity in a manner of reducing the environmental temperature in the monitoring interval, wherein the reduction of the environmental temperature includes reducing from 0℃ to minus 30℃, and obtaining the change of the spacer in the monitoring interval, wherein the change includes fatigue cracks appearing on the surface of the spacer;

[0014] S40: Applying a dynamic load to the spacer while reducing the environmental temperature, wherein the dynamic load is set according to the actual conductor tension of the power transmission line, the applied range is 1kN-100kN, and the characteristic change of the fatigue cracks on the surface of the spacer is analyzed in the applied range;

[0015] S50: Dividing the fulcrum of the spacer according to the characteristic change, wherein the fulcrum division includes dividing the fulcrum of the spacer into , ,... ; wherein, represents the divided th fulcrum, and the maximum conductor tension that can be borne by different fulcrums is calculated.

[0016] As a preferred scheme of the present application, wherein: in the S40, the characteristic change of the fatigue crack on the surface of the spacer bar is analyzed in the applied range, and the analysis method comprises strain analysis, and the strain analysis comprises strain peak value, strain distribution and strain cycle characteristics;

[0017] The strain peak value is the maximum strain value of the spacer bar under different load sizes.

[0018] The strain distribution is the distribution of the analyzed strain on the surface of the spacer bar.

[0019] The strain cycle characteristics are the cycle change rule of the strain with time.

[0020] In the S40, the characteristic change of the fatigue crack on the surface of the spacer bar is analyzed in the applied range, and the analysis method further comprises numerical simulation and analysis, and the numerical simulation and analysis comprises finite element analysis.

[0021] The finite element analysis comprises stress-strain distribution, crack propagation path prediction and fatigue life evaluation.

[0022] The stress-strain distribution is to analyze the stress-strain distribution on the surface and inside of the spacer bar to determine the stress concentration area of the spacer bar.

[0023] The crack propagation path prediction is to predict the propagation path of the crack corresponding to the fatigue crack under different load sizes, and to predict the propagation direction and rate of the crack based on the propagation path.

[0024] The fatigue life evaluation is to construct a fatigue life prediction model according to the predicted propagation direction and rate of the crack, to calculate the fatigue life of the spacer bar under different load sizes, and to predict the time of the occurrence and propagation of the crack based on the fatigue life.

[0025] As a preferred scheme of the present application, wherein: in the S50, the maximum conductor tension that can be borne by different support points is calculated, and the calculation is carried out according to the following formula:

[0026] ; wherein, represents the maximum conductor tension that can be borne by the plurality of support points.

[0027] In the formula, represents the maximum total load that can be borne by the spacer bar, represents the number of support points on the spacer bar, represents the stiffness of the th support point.

[0028] As a preferred scheme of the present application, wherein: the maximum conductor tension that different supporting points can bear is calculated, and the calculation is made according to the following formula:

[0029] ; wherein, represents the maximum stress that the multiple supporting points can bear;

[0030] In the formula, represents the maximum conductor tension that the multiple supporting points can bear; represents the length of the th supporting point, represents the cross-sectional area of the th supporting point.

[0031] As a preferred scheme of the present application, wherein: the fatigue life of the spacer under different load sizes is calculated, and the calculation is made according to the following formula:

[0032] ; wherein, represents the fatigue life of the th supporting point;

[0033] In the formula, represents the maximum stress that the multiple supporting points can bear, represents the fatigue limit of the material of which the spacer is made, represents the fatigue index of the material.

[0034] As a preferred scheme of the present application, wherein: wind force and vibration are exerted on each supporting point according to the calculated maximum conductor tension that different supporting points can bear, and when wind force and vibration are exerted on each supporting point, any one of the supporting points is divided into a lateral force point and a middle force point, the maximum wind force and the maximum vibration that the lateral force point and the middle force point corresponding to the supporting point can bear under the condition that the supporting point bears the maximum conductor tension are calculated, when the supporting point has borne the maximum conductor tension, the wind force and the vibration frequency that the lateral force point and the middle force point corresponding to the supporting point bear are collected, if the wind force and the vibration frequency do not reach the wind force and the vibration corresponding to the maximum wind force and the maximum vibration, it is determined that the spacer will not have fatigue cracks; otherwise, it is determined that the spacer will have fatigue cracks, and a warning is issued.

[0035] When the supporting point has not borne the maximum conductor tension, if the wind force and the vibration frequency that the lateral force point and the middle force point corresponding to the supporting point bear reach the wind force and the vibration corresponding to the maximum wind force and the maximum vibration, it is determined that the spacer will not have fatigue cracks.

[0036] As a preferred scheme of the present application, when the support point has been subjected to the maximum conductor tension, the wind force and the vibration frequency of the lateral force point and the intermediate force point corresponding to the support point are calculated, and if the wind force and the vibration frequency reach the maximum wind force and the maximum vibration, the deflection angle of the wind force at the center of the spacer is collected, and if the deflection angle is opposite to the angle of the support point on the spacer, it is determined that the fatigue crack on the surface of the spacer will not appear on the side deflected to the support point.

[0037] As a preferred scheme of the present application, the maximum wind force and the maximum vibration of the lateral force point and the intermediate force point corresponding to the support point under the condition that the support point is subjected to the maximum conductor tension are calculated, and the calculation is carried out according to the following formula:

[0038] In the formula, represents the maximum wind force;

[0039] In the formula, represents the air density, represents the maximum wind speed, represents the wind force coefficient, represents the windward area of the support point;

[0040] ;

[0041] In the formula, represents the maximum vibration acceleration, represents the maximum vibration frequency, represents the mass of the support point.

[0042] A terminal comprises a processor, an input interface, an output interface and a memory, which are connected to each other, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to invoke the program instructions to execute the method as described above.

[0043] A computer readable storage medium stores a computer program, the computer program comprises program instructions, and the program instructions, when executed by a processor, cause the processor to execute the method as described above.

[0044] Advantages:

[0045] 1、 The present application can analyze the characteristics of the surface fatigue cracks of the spacer rod in detail, including strain peak value, strain distribution, strain cycle characteristics, etc., through dynamic load application, strain analysis, numerical simulation (finite element analysis), etc., which can accurately predict the initiation, propagation path and fatigue life of the cracks, and can more effectively obtain the working conditions of the spacer rod in the natural environment;

[0046] 2、 By calculating the maximum conductor tension and stress that can be borne by different fulcrums, the distribution and structure design of the fulcrums of the spacer rod can be optimized, which helps to reasonably distribute the load and reduce stress concentration, thereby improving the overall fatigue performance and service life of the spacer rod;

[0047] 3、 The present application applies wind force and vibration to the fulcrum and collects relevant data, and when the maximum conductor tension borne by the fulcrum reaches the limit, if the wind force and vibration frequency exceed the maximum value that can be borne by the fulcrum, a warning is issued to indicate that fatigue cracks may occur, which can discover potential safety hazards in advance and avoid accidents;

[0048] 4、 When the fulcrum bears the maximum conductor tension, if the wind force deviation angle is opposite to the angle of the fulcrum, it is determined that cracks will not occur on the side deviated from the fulcrum, so that the present application can predict the possible location of the cracks according to the wind force deviation angle, improving the accuracy of the efficiency of the evaluation of the spacer rod. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0050] Fig. 1 The method flowchart of the embodiments of the present application;

[0051] Fig. 2 The flowchart structure of the embodiments of the present application. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely in the following with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0053] Since the fatigue performance evaluation of the power components or auxiliary parts in the prior art is all laboratory static tests, such laboratory static tests are difficult to truly reflect the actual working conditions of the power components or auxiliary parts in the natural environment.

[0054] Based on this, the present application provides a method for comprehensively evaluating the fatigue performance of a spacer in a power transmission line under a simulated natural environment, which can more truly reflect the stress condition and fatigue performance of the spacer in actual operation by simulating the conditions of climate (temperature, humidity, sunlight), wind and vibration in the natural environment, and can analyze the characteristic changes of the surface fatigue cracks of the spacer in detail by means of dynamic load application, strain analysis, numerical simulation (finite element analysis) and other means, so as to accurately predict the initiation, propagation path and fatigue life of the cracks.

[0055] The present application will be further described in detail below by means of examples and in conjunction with the accompanying drawings.

[0056] Reference Figs. 1-2 For an embodiment of the present application, the embodiment provides a method for comprehensively evaluating the fatigue performance of a spacer in a power transmission line under a simulated natural environment, which comprises the following steps:

[0057] S10: Simulate the relevant environment of the spacer, including climate, wind and vibration; the climate includes environmental temperature, air humidity and sunlight intensity;

[0058] In this embodiment, in a feasible implementation scheme, the spacer to be tested is installed on an experimental device simulating the conductor of the power transmission line, ensuring that the installation mode is consistent with the actual power transmission line;

[0059] Among them, the simulation of the climate includes simulating the temperature change (-20℃ to +50℃) and humidity change (10% to 90% relative humidity) in the natural environment through the temperature and humidity controller, refrigeration and heating equipment and humidifying and dehumidifying device, at the same time, the sunlight intensity is simulated by using the ultraviolet lamp to simulate the sunlight irradiation, the sunlight intensity is 300W / m² to 1000W / m²;

[0060] The simulation of the wind includes using an adjustable speed blower to simulate the natural wind, the wind speed range is 0.5m / s to 30m / s, by changing the wind direction and wind speed, the effect of wind of different directions and intensities on the spacer is simulated;

[0061] The simulation of the vibration includes using a vibration table to simulate the vibration of the conductor of the power transmission line, the vibration frequency range is 0.1Hz to 100Hz, the vibration acceleration range is 0.1g to 10g, so as to simulate the vibration condition of the conductor in actual operation;

[0062] S20: Based on climate setting, the monitoring interval includes setting climate change with a base value as the target. The base value includes an ambient temperature of 0°C.

[0063] S30: Simultaneously reduce air humidity and solar radiation intensity in the monitoring range by lowering the ambient temperature, including reducing the ambient temperature from 0°C to -30°C, and obtain changes in the spacer bars in the monitoring range, including fatigue cracks appearing on the surface of the spacer bars.

[0064] In this embodiment, in reality, steel has the characteristic of high temperature resistance. Under normal temperature and high temperature conditions, the performance of steel will not be negatively affected. Furthermore, extreme high temperature conditions (such as above 200°C) are rare. Therefore, in this embodiment, in combination with the actual situation, the rise in ambient temperature is not used as the fatigue assessment of the spacer bar. This approach has practical significance.

[0065] It should be noted that reducing air humidity and solar intensity in a way that lowers the ambient temperature includes reducing air humidity and solar intensity in a way that is consistent with the decrease in ambient temperature.

[0066] S40: Apply dynamic load to the spacer bar when the ambient temperature decreases. The dynamic load is set according to the conductor tension of the actual transmission line and the range of application is 1kN to 100kN. Analyze the characteristic changes of fatigue cracks on the surface of the spacer bar within the applied range.

[0067] S50: Divide the spacer into fulcrums based on characteristic changes. This fulcrum division includes dividing the spacer into fulcrums... , ,..., ;in, Indicates the division of the first Calculate the maximum conductor tension that can be withstood at each of the following support points;

[0068] In this embodiment, the fulcrum is the fulcrum on the spacer bar that fixes and supports the wire;

[0069] It should be emphasized that this embodiment covers multiple steps, from environmental simulation, monitoring range setting, environmental parameter adjustment to fatigue crack characteristic change analysis on the spacer surface, making the evaluation process more scientific, systematic and comprehensive, and helping to fully understand the fatigue performance changes of the spacer under different environmental conditions.

[0070] By simulating various relevant environmental factors such as climate, wind, and vibration, the stress and fatigue performance of spacers in actual natural environments can be more realistically reflected. This overcomes the limitations of traditional laboratory static testing, which cannot fully simulate actual working conditions, and provides a more realistic basis for the performance evaluation of spacers.

[0071] In S40, the characteristic changes of the fatigue cracks on the surface of the spacer bar are analyzed within the applied range, and the analysis includes strain analysis, which includes strain peak, strain distribution, and strain cycle characteristics;

[0072] Need to be explained, in a feasible implementation, strain gauges are installed on the surface of the spacer bar, the strain changes of the spacer bar under dynamic load are monitored in real time, and by analyzing the strain data, the stress state of the spacer bar under different load levels can be understood;

[0073] The strain peak is the maximum strain value of the spacer bar under different load sizes;

[0074] In this embodiment, the maximum strain value of the strain gauge under different load levels is recorded, and the strain peak will also increase with the increase of the load, and when the fatigue crack appears, the strain peak may change suddenly;

[0075] The strain distribution is the analysis of the distribution of strain on the surface of the spacer bar;

[0076] In this embodiment, fatigue cracks usually occur in stress concentration areas, so changes in strain distribution can provide clues for crack location;

[0077] The strain cycle characteristics are the cyclic variation rules of strain with time;

[0078] In this embodiment, during the fatigue crack propagation stage, the strain cycle may change nonlinearly;

[0079] The characteristic changes of the fatigue cracks on the surface of the spacer bar are analyzed within the applied range, and the analysis also includes numerical simulation and analysis, which includes finite element analysis;

[0080] Finite element analysis includes stress-strain distribution, crack propagation path prediction, and fatigue life assessment;

[0081] The stress-strain distribution is to analyze the stress-strain distribution on the surface and inside of the spacer bar to determine the stress concentration area of the spacer bar;

[0082] The crack propagation path prediction is to simulate the propagation path of the crack corresponding to the fatigue crack under different load sizes, and to predict the propagation direction and rate of the crack based on the propagation path;

[0083] The fatigue life assessment is to construct a fatigue life prediction model according to the predicted propagation direction and rate of the crack, to calculate the fatigue life of the spacer bar under different load sizes, and to predict the time of crack occurrence and propagation based on the fatigue life;

[0084] It should be noted that, in order to construct a numerical model of the spacer, dynamic loads are applied to the numerical model to simulate the stress-strain distribution and crack propagation of the spacer under different load magnitudes.

[0085] For fatigue life assessment, in one feasible implementation, a fatigue life prediction model can be constructed based on the fatigue performance data of the material used to manufacture the spacer and the combination of the predicted crack propagation direction and rate, to assess the fatigue life of the spacer under different load levels.

[0086] It is important to emphasize that by employing various methods such as strain analysis and numerical simulation and analysis, and analyzing the characteristic changes of fatigue cracks on the surface of spacer bars from multiple dimensions such as strain peak value, strain distribution, and strain cycle characteristics, we can gain a more comprehensive and in-depth understanding of the formation and development laws of cracks, and provide richer information for accurately evaluating the fatigue performance of spacer bars.

[0087] In S50, the maximum conductor tension that different support points can withstand is calculated using the following formula:

[0088] ;in, This indicates the maximum conductor tension that can be withstood among multiple supports;

[0089] In the formula, This indicates the maximum total load that the spacer can withstand. Indicates the number of fulcrums on the spacer bar. Indicates the first Stiffness of each support point;

[0090] In this embodiment, the maximum conductor tension that different support points can withstand is calculated by formula, and the force-bearing capacity of the support points is quantified. This provides clear quantitative indicators for the design and optimization of the spacer, which helps to rationally distribute the force on the support points, optimize the layout and structural design of the support points, and improve the overall load-bearing capacity and fatigue performance of the spacer.

[0091] Furthermore, the stiffness factor of the support points is introduced into the calculation formula, taking into account the possible stiffness differences of different support points, making the calculation results more consistent with the actual situation and more accurately reflecting the actual stress situation of each support point, thus providing a basis for the personalized design and optimization of spacers.

[0092] Calculating the maximum conductor tension that different support points can withstand also includes calculations based on the following formula:

[0093] ;in, This indicates the maximum stress that can be withstood among multiple support points;

[0094] In the formula, represents the maximum conductor tension that can be borne by the multiple support points; represents the length of the th support point, represents the cross-sectional area of the th support point;

[0095] In this embodiment, on the basis of the above calculation formula, the maximum stress of the support point is further calculated, and the stress condition of the support point is more carefully analyzed from the stress angle, so that the evaluation of the stress capacity of the support point is more comprehensive and in-depth, and the safety and reliability of the support point in actual use can be more accurately judged;

[0096] By calculating the maximum stress of the support point, the structure design of the support point can be optimized, for example, adjusting the cross-sectional area or length of the support point and other parameters, to reduce the stress level of the support point, improve the carrying capacity and fatigue resistance of the support point, and thus optimize the structure design of the entire spacer;

[0097] The fatigue life of the spacer under different load sizes is calculated according to the following formula:

[0098] ; wherein, represents the fatigue life of the th support point;

[0099] In the formula, represents the maximum stress that can be borne by the multiple support points, represents the fatigue limit of the material for manufacturing the spacer, represents the fatigue index of the material;

[0100] In this embodiment, the fatigue life of the support point is calculated by the formula, which can quantitatively evaluate the fatigue performance of the support point under different load sizes, so that the prediction of the fatigue life of the spacer is more specific and accurate, which helps to make maintenance and replacement plans in advance, and avoids the damage of the spacer and the fault of the power transmission line caused by the fatigue failure of the support point;

[0101] And the fatigue limit and fatigue index of the material are introduced into the calculation formula, which fully considers the influence of the fatigue characteristics of the material on the fatigue life of the support point, so that the calculation result is more consistent with the actual fatigue behavior of the material, and provides a more accurate reference basis for the material selection and design optimization of the spacer;

[0102] According to the calculated maximum conductor tension that each support point can bear, wind force and vibration are applied to each support point, including distinguishing any one support point into a lateral force point and a middle force point, calculating the maximum wind force and maximum vibration that the lateral force point and the middle force point corresponding to the support point can bear under the condition that the support point bears the maximum conductor tension, when the spacer is used in the real natural environment, if the wind force and vibration frequency suffered by the lateral force point and the middle force point corresponding to the support point do not reach the wind force and vibration corresponding to the maximum wind force and the maximum vibration, it is determined that the spacer will not appear fatigue cracks; otherwise, it is determined that the spacer will appear fatigue cracks and issue a warning;

[0103] When the support point does not bear the maximum conductor tension, if the wind force and vibration frequency suffered by the lateral force point and the middle force point corresponding to the support point reach the wind force and vibration corresponding to the maximum wind force and the maximum vibration, it is determined that the spacer will not appear fatigue cracks;

[0104] It should be noted that in actual use, the wind force suffered by the spacer is not balanced, and the reasons for the unbalanced wind force include the influence of topography and microclimate conditions, as well as the arrangement of the conductor and the installation position of the spacer. Among them, for topographic factors, the power transmission line often crosses different terrains, such as valleys, ridges, plains, etc. In the valley, the wind speed may increase due to the funnel effect; while on the ridge, the wind speed may decrease due to the blocking of the terrain, and this topographic difference will cause the wind force suffered by the spacer to be different at different positions.

[0105] Moreover, the meteorological conditions of local areas (such as local airflow, vortex) will also cause the unbalance of wind force, for example, near buildings or trees, the wind speed may change due to the obstruction of obstacles;

[0106] The arrangement of the conductor (such as horizontal arrangement, vertical arrangement, triangular arrangement) will affect the distribution of the wind force suffered by the spacer, for example, the vertical arrangement and the triangular arrangement of the conductor have better wind suppression effect after installing the spacer, while the horizontal arrangement of the conductor is difficult to effectively suppress the wind force;

[0107] The installation position of the spacer will also affect the wind force it suffers, installing the spacer at different positions of the conductor may cause differences in wind force, for example, installing the spacer at the middle position of the conductor may suffer larger wind force, while near the tower, the wind force may be relatively small;

[0108] The change of wind direction will also affect the wind force suffered by the spacer, when the wind direction is perpendicular to the arrangement direction of the conductor, the wind force suffered by the spacer is the largest; while when the wind direction is parallel to the arrangement direction of the conductor, the wind force suffered by the spacer is relatively small.

[0109] Need to emphasize that, on the basis of considering the maximum conductor tension borne by the support point, further wind force and vibration are exerted on the support point, and the influence of wind force and vibration on the fatigue performance of the spacer is comprehensively considered, so that the evaluation result is more comprehensive and accurate, and the stress condition and fatigue state of the spacer in actual operation can be more truly reflected;

[0110] By collecting the wind force and vibration frequency suffered by the lateral force point and the intermediate force point of the support point, and comparing with the maximum wind force and maximum vibration that the support point can bear, the early warning function of the fatigue crack of the spacer is realized, when the wind force and vibration exceed the bearing capacity of the support point, timely warning can be issued to remind relevant personnel to take measures to avoid further expansion of the fatigue crack and damage of the spacer;

[0111] When the support point has borne the maximum conductor tension, if the wind force and vibration frequency suffered by the lateral force point and the intermediate force point corresponding to the support point reach the wind force and vibration corresponding to the maximum wind force and the maximum vibration, the deflection angle of the wind force suffered by the center of the spacer is collected, if the deflection angle is opposite to the angle of the support point on the spacer, it is determined that the fatigue crack on the surface of the spacer will not appear on the side deviated from the support point;

[0112] Need to be explained, according to the research experience of the applicant, there is a certain relationship between the wind deflection angle and the fatigue crack, when the surface of the spacer is blown by strong wind, the wind will produce pressure distribution on the surface, if the deflection angle of the wind is uneven, it will lead to stress concentration in some areas, these stress concentration areas are usually high risk areas of fatigue crack initiation, if the deflection angle of the wind leads to stress concentration in a certain direction, then the crack will initiate along the direction corresponding to the stress direction;

[0113] Therefore, if the deflection angle is opposite to the angle of the support point on the spacer, it is determined that the fatigue crack on the surface of the spacer will not appear on the side deviated from the support point, and this determination of the embodiment has practical significance;

[0114] Need to emphasize that, when the support point bears the maximum conductor tension and the wind force and vibration frequency reach the maximum value, by collecting the deflection angle of the wind force suffered by the center of the spacer, it can be judged whether the crack will appear on the side deviated from the support point, which provides a new idea and method for crack detection and prevention;

[0115] This method can reduce the range of crack detection to a certain extent, avoid comprehensive detection of the whole spacer, thereby improving the efficiency of crack detection, reducing the detection cost and workload, and also helping to more accurately locate the position of the crack, providing guidance for subsequent repair and maintenance;

[0116] The maximum wind force and maximum vibration of the lateral force point and the middle force point corresponding to the fulcrum under the condition that the fulcrum bears the maximum conductor tension are calculated according to the following formula:

[0117] In the formula, represents the maximum wind force;

[0118] In the formula, represents the air density, represents the maximum wind speed, represents the wind force coefficient, represents the windward area of the fulcrum;

[0119] ;

[0120] In the formula, represents the maximum vibration acceleration, represents the maximum vibration frequency, represents the mass of the fulcrum;

[0121] In the embodiment, the wind force coefficient is related to the shape of the fulcrum, and is usually 0.8-1.2;

[0122] The quantitative indexes such as the maximum wind force and the maximum vibration acceleration calculated can intuitively reflect the wind force and vibration bearing limit of the fulcrum under the condition of bearing the maximum conductor tension, so that the wind force and vibration evaluation of the fulcrum is more specific and accurate, and provides strong support for the design, selection and operation and maintenance of the spacer.

[0123] A terminal comprises a processor, an input interface, an output interface and a memory, which are connected to each other, wherein the memory is used for storing a computer program, the computer program comprises program instructions, and the processor is configured to invoke the program instructions to execute the method as described above.

[0124] A computer readable storage medium stores a computer program, the computer program comprises program instructions, and the program instructions, when executed by a processor, cause the processor to execute the method as described above.

[0125] To sum up, the application can more truly reflect the stress condition and fatigue performance of the spacer in actual operation by simulating the climate (temperature, humidity, sunshine), wind force and vibration and other conditions in the natural environment, and can analyze the characteristic change of the surface fatigue crack of the spacer in detail by means of dynamic load application, strain analysis, numerical simulation (finite element analysis) and other means, so as to accurately predict the initiation, propagation path and fatigue life of the crack.

[0126] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced, without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A method for comprehensive evaluation of fatigue performance of a spacer damper for a power transmission line in a natural environment, characterized in that, The method comprises the following steps: S10: simulating the relevant environment of the spacer, the relevant environment including climate, wind force and vibration; the climate including ambient temperature, air humidity and sunshine intensity; S20: setting the monitoring interval based on the climate, the monitoring interval including setting the change of the climate with a basic value as the setting target, the basic value including ambient temperature of 0℃; S30: synchronously reducing the air humidity and sunshine intensity in a manner of reducing the ambient temperature in the monitoring interval, the reduction of the ambient temperature including from 0℃ to -30℃, and obtaining the change of the spacer in the monitoring interval, the change including the fatigue crack appearing on the surface of the spacer; S40: applying dynamic load to the spacer while reducing the ambient temperature, the dynamic load being set according to the actual conductor tension of the power transmission line, the applied range being 1kN-100kN, and analyzing the characteristic change of the fatigue crack on the surface of the spacer in the applied range; S50: According to the feature change, the support point of the spacer is divided, and the support point of the spacer is divided into , , , ; wherein indicates the divided th support point, and the maximum conductor tension that can be borne by different support points is calculated; applying wind force and vibration to each support point according to the calculated maximum conductor tension that each support point can bear, when applying wind force and vibration to each support point, including distinguishing any one of the support points as a lateral force point and a middle force point, calculating the maximum wind force and the maximum vibration that the lateral force point and the middle force point corresponding to the support point can bear under the condition that the support point bears the maximum conductor tension, when the spacer is used in the real natural environment, when the support point has borne the maximum conductor tension, collecting the wind force and the vibration frequency suffered by the lateral force point and the middle force point corresponding to the support point, if the wind force and the vibration frequency do not reach the wind force and the vibration corresponding to the maximum wind force and the maximum vibration, it is determined that the spacer will not appear fatigue crack; otherwise, it is determined that the spacer will appear fatigue crack and an early warning is issued; when the support point does not bear the maximum conductor tension, if the wind force and the vibration frequency suffered by the lateral force point and the middle force point corresponding to the support point reach the wind force and the vibration corresponding to the maximum wind force and the maximum vibration, it is determined that the spacer will not appear fatigue crack.

2. The method for comprehensive evaluation of fatigue performance of the spacer dam of the power transmission line in the simulated natural environment according to claim 1, characterized in that, In the S40, the characteristic change of the fatigue crack on the surface of the spacer is analyzed in the applied range, the analysis mode including strain analysis, the strain analysis including strain peak value, strain distribution and strain cycle characteristics; the strain peak value is the maximum strain value of the spacer under different load sizes; the strain distribution is the distribution of the strain on the surface of the spacer; the strain cycle characteristics are the cycle change law of the strain with time; the characteristic change of the fatigue crack on the surface of the spacer is analyzed in the applied range, the analysis mode further including numerical simulation and analysis, the numerical simulation and analysis including finite element analysis; the finite element analysis includes stress-strain distribution, crack propagation path prediction and fatigue life evaluation; the stress-strain distribution is to analyze the stress-strain distribution on the surface and inside of the spacer to determine the stress concentration area of the spacer; The crack propagation path prediction is to predict the propagation direction and rate of the crack by simulating the propagation path of the crack corresponding to the fatigue crack under different load sizes; The fatigue life evaluation is to construct a fatigue life prediction model according to the predicted propagation direction and rate of the crack, calculate the fatigue life of the spacer under different load sizes, and predict the time of the crack occurrence and propagation based on the fatigue life.

3. The method for comprehensive evaluation of fatigue performance of the spacer dam of the power transmission line in the simulated natural environment according to claim 1, characterized in that, In the S50, the maximum wire tension that can be borne by different fulcrums is calculated according to the following formula: ; wherein, represents the maximum wire tension that can be borne by a plurality of fulcrums. wherein represents the maximum total load that the spacer can withstand, represents the number of fulcrums on the spacer, represents the stiffness of the th fulcrum.

4. The method for comprehensive evaluation of fatigue performance of the spacer dam of the power transmission line in the simulated natural environment according to claim 3, characterized in that, calculating the maximum conductor tension that can be supported by the different support points also includes calculating according to the following formula: ; wherein represents the maximum stress that can be supported by the plurality of support points; wherein represents the maximum conductor tension that can be sustained by a plurality of said fulcrums; represents the length of the th said fulcrum, represents the cross-sectional area of the th said fulcrum.

5. The method for comprehensive evaluation of the fatigue performance of a spacer dam for a power transmission line in a natural environment according to claim 2, characterized in that, The fatigue life of the spacer under different load sizes is calculated according to the following formula: ; wherein, represents the fatigue life of the j th supporting point. In the formula, ;in, Indicates the first Fatigue life of the aforementioned fulcrum; wherein represents the maximum stress that can be sustained by a plurality of said fulcrums, represents the fatigue limit of the material from which said spacers are made, represents the fatigue index of said material.

6. The method for comprehensive evaluation of the fatigue performance of a spacer dam for a power transmission line in a natural environment according to claim 1, characterized in that, When the fulcrum has been subjected to the maximum conductor tension, if the wind force and vibration frequency suffered by the lateral force point and the intermediate force point corresponding to the fulcrum reach the wind force and vibration corresponding to the maximum wind force and the maximum vibration, the deflection angle of the wind force suffered by the center of the spacer is collected, and if the deflection angle is opposite to the angle of the fulcrum on the spacer, it is determined that the fatigue crack on the surface of the spacer will not appear on the side deflected to the fulcrum.

7. The method for comprehensive evaluation of the fatigue performance of a spacer dam for a power transmission line in a natural environment according to claim 1, characterized in that, The maximum wind force and maximum vibration that the lateral force point and the intermediate force point corresponding to the support point can bear in the case that the support point bears the maximum conductor tension are calculated according to the following formula: ; wherein, represents the maximum wind force; wherein denotes the air density, denotes the maximum wind speed, denotes the wind force coefficient, denotes the windward area of the pivot point; wherein denotes the maximum vibration acceleration, denotes the maximum vibration frequency, denotes the mass of the pivot point.

8. A terminal, characterized by comprising: The computer readable storage medium stores a computer program, and the computer program includes program instructions. When the program instructions are executed by the processor, the processor executes the method according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program includes program instructions. When the program instructions are executed by the processor, the processor executes the method according to any one of claims 1-7.

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