Iced conductor galloping dynamic tension and tower stress calculation method and system

Abstract

The invention discloses an iced conductor galloping dynamic tension and tower stress calculation method and system, and belongs to the field of iced conductor galloping damage and prevention, and the method comprises the steps: building a power transmission tower, a conductor and an insulator model, and forming a conductor tower system; applying an ice load to the lead tower system by changing the density, and constructing an icing equivalent model of the power transmission lead, the tower and the insulator; constructing a power transmission line-tower system icing equivalent model, and applying a wind load to a power transmission conductor and a tower; repeating the above steps, calculating the dynamic tension of the iced conductor and the stress of the transmission tower under different ice loads and wind loads, and constructing a calculation model of the tension of the iced conductor and the stress of the transmission tower; and acquiring real-time meteorological data and icing monitoring data, inputting related parameters into the icing conductor tension and tower stress calculation model to obtain a conductor tension and tower stress calculation result, and taking corresponding early warning measures according to a preset risk level corresponding to the calculation result.

Description

Technical Field

[0001] The present invention relates to the field of the hazards and prevention of galloping of ice-covered conductors, and particularly to a method and system for calculating the dynamic tension of ice-covered conductors and the stress of transmission towers during galloping. Background Art

[0002] Power load centers are often far from energy-rich areas, and this geographical feature directly drives the urgent need of the power system for long-distance and large-scale power transmission. With the improvement of the voltage level of the power system and the expansion of the construction scale, power lines have to pass through numerous harsh meteorological regions. In recent years, global climate change has led to frequent extreme meteorological events, and the power grid has suffered increasingly serious impacts and losses due to galloping disasters. Therefore, it is particularly crucial to calculate the dynamic tension of conductors and the stress of transmission towers under ice-covered conditions. This not only helps the staff to take preventive measures in advance, but also is crucial for preventing wire breakage accidents and tower collapses caused by conductor galloping, ensuring the safe and stable operation of the power grid under harsh climate conditions.

[0003] The technical solution of the prior art document 1 (CN117688766A) addresses the problem of calculating the wind-induced tension of unevenly ice-covered transmission conductors in the technical field of ice disaster prevention and mitigation of transmission lines. Based on the force conditions of the transmission conductors, nonlinear differential equations of the horizontal and vertical forces of the transmission conductors are established, and a wind-induced displacement function model in the horizontal and vertical directions and a compatibility equation are constructed to solve the wind-induced tension of the transmission conductors; however, the calculation model constructed in the prior art document 1 depends on preset force data, and there are problems of real-time performance and adaptability in the dynamic coupling ability of the model.

[0004] The technical solution of the prior art document 2 (CN113553747A) addresses the problem of analyzing the mechanical characteristics and state assessment of ice-covered transmission towers in the technical field of ice-covered transmission tower monitoring. The mechanical characteristics of the transmission towers are evaluated by using finite element simulation and database management, but it depends on manual analysis and lacks automatic algorithm calibration, resulting in a lag in model update and difficulty in quickly responding to complex working conditions, and there are problems of dynamic performance and automation in dynamic load modeling. Summary of the Invention

[0005] A method for calculating the dynamic tension of ice-covered conductors and the stress of transmission towers proposed by the present invention can quickly and accurately calculate the dynamic tension of ice-covered conductors and the stress of transmission towers in an ice-covered environment, which helps relevant personnel to timely discover the problem of overloading of the line force and take preventive measures in time to prevent wire breakage and tower collapse of the transmission line caused by ice coverage.

[0006] The first aspect of the present invention provides a method for calculating the dynamic tension of ice-covered conductors and the stress of transmission towers, including the following steps:

[0007] Establish models of transmission towers, conductors and insulators, and form a conductor-tower system;

[0008] Apply ice load to the conductor-tower system by changing the density, including: calculating the equivalent density of the transmission conductor, tower and insulator structures in the ice-covered state to update the material property parameters of the corresponding components, and constructing an equivalent ice-covered model of the transmission conductor, tower and insulator;

[0009] Assemble the equivalent ice-covered models of the transmission tower, insulator and conductor to construct an equivalent ice-covered model of the transmission line-tower system, and apply wind load to the transmission conductor and tower;

[0010] Repeat the above steps, calculate the dynamic tension of the ice-covered conductor and the stress of the transmission tower under different ice loads and wind loads, respectively fit the calculation formulas of ice-wind load and ice-covered conductor tension, tower stress, and construct a calculation model of ice-covered conductor tension and tower stress;

[0011] Obtain real-time meteorological data and ice-covered monitoring data, and input relevant parameters into the calculation model of ice-covered conductor tension and tower stress to obtain the calculation results of conductor tension and tower stress.

[0012] Optionally, applying wind load to the transmission conductor and tower in the equivalent ice-covered model of the transmission line-tower system includes:

[0013] Apply wind load to the transmission conductor and tower using the resistance coefficient of the ice-covered conductor, the wind load adjustment coefficients of the conductor and tower, the calculated outer diameter of the conductor after ice covering, and the shape coefficients of the conductor and tower during ice covering. The wind load includes the reference wind pressure, the wind pressure height change coefficient, the wind load shape coefficient, and the wind load adjustment coefficient.

[0014] Optionally, calculating the wind load of the ice-covered conductor per unit length includes:

[0015] The wind load of the ice-covered conductor per unit length is the product of the wind pressure non-uniformity coefficient, the standard value of the reference wind pressure, the wind pressure height change coefficient, the resistance coefficient of the ice-covered conductor, the wind load adjustment coefficient of the ice-covered conductor, the calculated outer diameter of the conductor after ice covering, and the square of the sine value of the angle between the horizontal wind and the line direction;

[0016] Calculating the wind load of the ice-covered tower per unit length includes:

[0017] The wind load of the ice-covered tower per unit length is the product of the wind load adjustment coefficient of the tower, the standard value of the reference wind pressure, the wind pressure height change coefficient, the shape coefficient of the conductor, the shape coefficient of the tower, and the calculated outer diameter of the conductor after ice covering.

[0018] Optionally, calculating the dynamic tension of the ice-covered conductor under different ice loads and wind loads includes:

[0019] Correct the static tension of the conductor:

[0020]

[0021] Among them, \(T_0\) is the initial static tension of the conductor, \(E\) is the comprehensive elastic modulus, \(A\) is the cross-sectional area of the conductor, \(\Delta l\) is the change in the length of the conductor caused by galloping, \(\beta'\) is the elevation angle of the wind deflection plane, \(\theta\) is the torsional angle of the conductor, and \(\varphi\) is the wind deflection angle;

[0022] Combined with modal perturbation, a nonlinear relationship between ice-wind load and the dynamic tension of the ice-covered conductor is established:

[0023] \(T\) d \(=T\) eq \(+k_1\cdot(\gamma\) ice \(\cdot d\) ice ) 0.8 \(+k_2\cdot(\rho\) air \(\cdot U\) 2 \(\cdot C\) d \(\cdot D\) eq ) 1.2

[0024] Among them, \(T\) eq is the equivalent axis tension after correcting the initial static tension of the conductor, \(\gamma\) ice is the specific gravity of the ice load, \(d\) ice is the ice thickness, \(U\) is the wind speed, \(C\) d is the aerodynamic drag coefficient, \(D\) eq is the equivalent diameter of the conductor, \(\rho\) air is the air density, \(k_1\) is the steady-state aerodynamic correction coefficient; \(k_2\) is the dynamic turbulence correction coefficient.

[0025] Optionally, the calculation of the stress of the transmission tower under different ice loads and wind loads includes:

[0026] Construct the stress transfer equation of the tower node:

[0027]

[0028] Among them, \(L\) i is the conductor span, \(\alpha\) i is the suspension point inclination angle, \(A\) tower is the cross-sectional area of the tower member, \(Z\) is the section modulus, \(\eta\) damp is the damping correction coefficient, \(T\) d,i is the dynamic tension of the \(i\)-th span of the conductor.

[0029] Optionally, the fitting of the calculation formulas for ice-wind load, the tension of the ice-covered conductor, and the stress of the tower includes:

[0030] According to the calculation results and simulation result data of the dynamic tension of the ice-covered conductor and the stress of the transmission tower under different ice loads and wind loads, construct a dataset of the peak value of the dynamic tension of the ice-covered conductor and the stress of the key nodes of the tower;

[0031] The Levenberg-Marquardt algorithm is used to optimize the parameters of the non-linear relationship between ice-wind load and dynamic tension and the stress transfer equation of the tower pole node. The objective function is as follows:

[0032]

[0033] Where, T d,calc is the calculated value of the dynamic tension of the wire, T d,sim is the simulated value of the wire tension, σ calc is the calculated value of the stress of the tower pole node, σ sim is the simulated value of the stress of the tower pole node.

[0034] Optionally, the fitting formulas for ice-wind load, ice-covered wire tension, and tower pole stress obtained by optimization include:

[0035] The fitting formula for ice-wind load and ice-covered wire tension is:

[0036]

[0037] Where, T eq is the equivalent axis tension after correcting the initial static tension T0 of the wire, h is the ice thickness, D is the wire diameter, ρ ice is the ice density, U is the wind speed, L is the wire span;

[0038] The fitting formula for ice-wind load and tower pole stress is:

[0039]

[0040] α i is the suspension point dip angle, θ i is the wind deflection angle, η ice is the ice correction, η wind is the wind load correction.

[0041] Optionally, the relevant parameters input into the calculation model of ice-covered wire tension and tower pole stress include: predicted wind speed in the next 72 hours, real-time monitored equivalent ice thickness, ice density, wire span, suspension angle, and initial static tension.

[0042] Optionally, the corresponding early warning measures taken according to the preset risk level corresponding to the calculation result include:

[0043] The preset risk levels include normal level, attention level, and early warning level;

[0044] The dynamic tension threshold corresponding to the normal level is Td < 0.5T max , and the tower pole stress threshold is σ < 0.6σ y , and the early warning measure is to maintain routine monitoring;

[0045] The dynamic tension threshold corresponding to the attention level is 0.5T max ≤Td<0.8T max The tower stress threshold is 0.6σ y ≤σ<0.8σ y The early warning measures are to start the UAV inspection and increase the monitoring frequency;

[0046] The dynamic tension threshold corresponding to the warning level is Td≥0.8T max The tower stress threshold is σ≥0.8σ y The early warning measures are to start DC de-icing, mechanical de-icing or tension adjustment;

[0047] Among them, T max is the peak value of the dynamic tension of the ice-covered conductor, and σ y is the yield stress of the tower material.

[0048] The second aspect of the present invention provides a calculation system for the dynamic tension of ice-covered conductor galloping and the tower stress, based on the calculation method for the dynamic tension of ice-covered conductor galloping and the tower stress described in the first aspect of the present invention. The system includes:

[0049] A model establishment module for constructing models of transmission towers, conductors and insulators and combining them into a conductor-tower system;

[0050] An ice load application module for calculating the equivalent density of each structure under the ice-covered state, updating the material properties of the corresponding components, and constructing an ice-covered equivalent model;

[0051] A wind load application module for applying wind load to the ice-covered equivalent model of the transmission line-tower system;

[0052] A calculation and modeling module for calculating the dynamic tension of the conductor and the tower stress under different ice and wind loads, fitting calculation formulas, and constructing a calculation model;

[0053] A data processing module for obtaining real-time meteorological and ice-covered monitoring data, inputting them into the calculation model, and obtaining the calculation results of the tension of the ice-covered conductor and the tower stress.

[0054] The present invention has the following beneficial effects compared with the prior art:

[0055] 1. Based on the application of ice load and wind load on the conductor and the tower, the present invention constructs relevant fitting formulas, which can directly calculate the dynamic tension of the ice-covered conductor and the tower stress, improve the calculation efficiency, provide more reliable data support for engineering personnel, quickly master the mechanical characteristics of the transmission line under the ice-covered state, save time and energy, and more efficiently meet the line evaluation requirements in actual work.

[0056] 2. By fitting the relationships among ice load, wind load, dynamic tension of the ice-covered conductor, and tower stress, the present invention shortens the calculation time, achieves the goal of quickly obtaining calculation results, and overcomes the problem of slow simulation calculation speed.

[0057] 3. By constructing a calculation model, the present invention can quickly obtain the dynamic tension of the ice-covered conductor and tower stress based on the acquired real-time meteorological data and ice-coverage monitoring data, can grasp the stress state of the line in real time, helps relevant personnel timely discover the problem of overloaded line stress, and timely take preventive measures to prevent the transmission line from breaking and the tower from collapsing due to ice coverage. Brief Description of the Drawings

[0058] Figure 1 It is a schematic flow chart of the calculation method for the dynamic tension of the ice-covered conductor and tower stress in the embodiment of the present invention;

[0059] Figure 2 It is a schematic plan view of the tower model in this embodiment;

[0060] Figure 3 It is a schematic cross-sectional view of the simplified insulator model in this embodiment;

[0061] Figure 4 It is a schematic cross-sectional model view of the ice-covered conductor in this embodiment;

[0062] Figure 5 It is the assembly model of the transmission tower, insulator, and conductor in this embodiment;

[0063] Figure 6 It is the wind attack angle - conductor dynamic tension curve of the ice-covered conductor in this embodiment;

[0064] Figure 7 It is the ice thickness - conductor dynamic tension curve of the ice-covered conductor in this embodiment;

[0065] Figure 8 It is the wind speed - conductor dynamic tension curve of the ice-covered conductor in this embodiment;

[0066] Figure 9 It is the wind attack angle - maximum tower stress curve of the transmission tower in this embodiment;

[0067] Figure 10 It is the ice thickness - maximum tower stress curve of the transmission tower in this embodiment;

[0068] Figure 11 It is the wind speed - maximum tower stress curve of the transmission tower in this embodiment. Detailed Embodiments

[0069] To make the objectives, technical solutions and advantages of the present invention more clear, the following will clearly and completely describe the technical solutions of the present invention with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0070] Referring to Figure 1 , in Embodiment 1 of the present invention, a method for calculating the dynamic tension of an ice-covered conductor and the stress of a tower is provided, including the following steps:

[0071] S1: By using engineering modeling software, models of transmission towers, conductors and insulators are respectively established, as Figures 2-4 shown, and a conductor-tower system is formed.

[0072] Preferably, the S1 includes:

[0073] Select the required models of transmission towers, conductors and insulators, refer to the design drawings, establish models of transmission towers, conductors and insulators in CAD respectively, and form a conductor-tower system, as Figure 5 shown.

[0074] Specifically, Figure 2 shows the schematic plan view of the tower model in this embodiment; Figure 3 shows the schematic cross-sectional view of the simplified insulator model in this embodiment; Figure 4 shows the schematic cross-sectional model of the ice-covered conductor in this embodiment, Figure 4 wherein, D represents the conductor diameter, and b represents the ice thickness.

[0075] It should be noted that the present invention restores the actual structure of the transmission line through modeling, laying a foundation for accurately simulating the mechanical responses under ice load and wind load subsequently, and helping to accurately evaluate the operating state of the transmission line in a complex environment.

[0076] S2: Apply ice load to the conductor-tower system by changing the density, including calculating the equivalent density of the transmission conductor, tower and insulator structures in the ice-covered state by using an external calculation tool, importing the equivalent density parameters into the engineering modeling software, updating the material property parameters of the corresponding components, and constructing an ice-covered equivalent model of the transmission conductor, tower and insulator.

[0077] Preferably, in the S2, the equivalent density is calculated by an external calculation tool according to the principle of mass conservation. The external calculation tool includes MATLAB, and the calculation result is input into the CAD software to update the material properties of the transmission conductor, tower and insulator.

[0078] Preferably, in the S2, the specific application of ice load to the conductor-tower system includes:

[0079] The parameters of the ice load include ice thickness, ice density, ice type, and ice shape characteristics. The ice density is set to 900 kg / m 3 , the ice type is mixed rime, and the ice shape characteristics are crescent-shaped for ice load application.

[0080] The ice load is applied by the method of changing density. According to the principle of mass conservation, after calculating the equivalent density of the total volume when a specific thickness of ice layer adheres to an object, the equivalent densities of the transmission line conductors, towers, and insulators after icing are calculated as shown in Table 1-3. And the corresponding equivalent densities are set as the densities of the transmission line conductors, towers, and insulators to obtain a simplified equivalent model of the transmission line conductors, towers, and insulators with ice.

[0081] It should be noted that by calculating the equivalent density and constructing an equivalent model of icing, the present invention can more accurately simulate the influence of icing on the transmission line structure, taking into account factors such as ice thickness, density, type, and shape characteristics, making the simulation results closer to the actual icing conditions.

[0082] Exemplarily, the equivalent densities of the transmission line conductors, transmission towers, and insulators in this embodiment are shown in Table 1-3:

[0083] Table 1 Equivalent density of transmission line conductors with ice in this embodiment

[0084]

[0085] Table 2 Equivalent density of transmission towers with ice in this embodiment

[0086]

[0087] Table 3 Equivalent density of insulators with ice in this embodiment

[0088]

[0089] S3: Assemble the equivalent models of the transmission tower, insulator, and conductor with ice, construct an equivalent model of the transmission line - tower system with ice and import it into the computational fluid dynamics simulation software, and apply wind loads to the transmission line conductors and towers;

[0090] Preferably, the S3 specifically includes:

[0091] Assemble the equivalent models of the transmission tower, insulator, and conductor with ice that have been updated in CAD. According to the suspension method of the conductors and insulators on the tower, assemble them into a three - transmission - tower two - span transmission line model, as Figure 5 shown. After obtaining the overall assembled model, import the model into the Fluent software.

[0092] Preferably, in step S3, applying wind loads to the transmission line and tower system in the computational fluid dynamics simulation software includes:

[0093] Applying wind loads to the transmission line and tower using the resistance coefficient of the ice-covered conductor, the wind load adjustment coefficients of the conductor and tower, the calculated outer diameter of the conductor after icing, and the shape coefficients of the conductor and tower during icing. The wind loads include the reference wind pressure, the wind pressure height change coefficient, the wind load shape coefficient, and the wind load adjustment coefficient;

[0094] Step S4 for applying wind loads to the conductor and tower includes that the wind load calculation formula for the ice-covered conductor per unit length is:

[0095] W x =α·W0·μ z ·C D ·β c ·d eq ·sin 2 θ

[0096] The wind load calculation formula for the ice-covered conductor is similar. The wind load calculation formula for the ice-covered tower per unit length is:

[0097] W s =β z ·μ z ·μ sc ·μ r ·d eq ·W0

[0098] W x is the wind load of the ice-covered conductor per unit length, W s is the wind load of the ice-covered tower per unit length, α is the wind pressure non-uniformity coefficient. When the maximum wind speed does not exceed 20 m / s, it can be taken as 1. W0 is the standard value of the reference wind pressure, which is mainly related to the square of the wind speed. μ z is the wind pressure height change coefficient, which is related to the height from the ground. μ sc is the shape coefficient of the conductor, μ r is the shape coefficient of the tower. C D is the resistance coefficient of the ice-covered conductor, d eq is the calculated outer diameter of the conductor after icing, and θ is the angle between the horizontal wind and the line direction. β C is the wind load adjustment coefficient of the ice-covered conductor, β Z is the wind load adjustment coefficient of the tower.

[0099] S4: Repeat the above steps to calculate the dynamic tension of the ice-covered conductor and the stress of the transmission tower under different ice loads and wind loads. Based on the calculation results, fit the calculation formulas of ice-wind loads and the tension of the ice-covered conductor and the stress of the tower, and construct a calculation model for the tension of the ice-covered conductor and the stress of the tower;

[0100] Preferably, in S4, the calculation formulas for the dynamic tension of the ice-covered conductor and the stress of the transmission tower are as follows:

[0101] Based on the line length method, the concept of equivalent axial tension is introduced to correct the initial static tension of the conductor, so as to correct the application of the existing Hooke's law in the wind deflection plane:

[0102]

[0103] T0 is the initial static tension of the conductor, E is the comprehensive elastic modulus, A is the cross-sectional area of the conductor, Δl is the change in the length of the conductor caused by galloping, β′ is the elevation angle in the wind deflection plane, θ is the conductor torsion angle, and φ is the wind deflection angle.

[0104] Combined with the modal perturbation method, a nonlinear relationship between ice-wind load and dynamic tension is established:

[0105] T d =T eq +k1·(γ ice ·d ice ) 0.8 +k2·(ρ air ·U 2 ·C d ·D eq ) 1.2

[0106] Among them, T eq is the equivalent axial tension after correcting the initial static tension of the conductor, γ ice is the specific gravity of the ice load, d ice is the ice thickness, U is the wind speed, C d is the aerodynamic drag coefficient, D eq is the equivalent diameter of the conductor, ρ air is the air density, k1 is the steady-state aerodynamic correction coefficient, and its value range is 0.8 - 1.2, and the default value is 1.0; k2 is the dynamic turbulence correction coefficient, and its value range is 0.05 - 0.15, and the default value is 0.10.

[0107] Based on the beam element theory, the stress transfer equation of the tower node is constructed:

[0108]

[0109] Among them, L i is the conductor span, α i is the suspension point inclination angle, A tower is the cross-sectional area of the tower member, Z is the section modulus, η damp is the damping correction coefficient, T d,i is the dynamic tension of the i-th span of the conductor. (Taking the three-tower two-span line model as an example, n takes 2).

[0110] Specifically, the calculation results of the dynamic tension of the ice-covered conductor and the stress of the transmission tower are as Figures 6-11 shown.

[0111] Preferably, based on the calculation results, the fitting calculation formulas of ice-wind load, ice-covered conductor tension, and tower stress include:

[0112] According to the calculation results and simulation results of the dynamic tension of the ice-covered conductor and the stress of the transmission tower under different ice loads and wind loads, construct the peak value T of the dynamic tension of the ice-covered conductor d，max and the stress σ tower data set of key tower nodes. The key tower nodes are stress concentration areas clearly marked in the tower design, such as suspension points, connections between cross arms and main members, and cross diagonal member nodes;

[0113] Apply the Levenberg-Marquardt algorithm to optimize the parameters, and the objective function is:

[0114]

[0115] where T d,calc is the calculated value of the conductor dynamic tension, T d,sim is the Fluent simulation value of the conductor tension, σ calc is the calculated value of the tower node stress, and σ sim is the simulation value of the tower node stress.

[0116] Further preferably, the Levenberg-Marquardt (LM) algorithm combines the Gauss-Newton method and the gradient descent method, and balances the convergence speed and stability by dynamically adjusting the damping factor λ. Its core iteration formula is:

[0117] Δθ = -(J T J + λI) -1 J T r

[0118] Set the initial parameter θ0 and the damping factor λ0 = 0.001. Calculate the residual r(θ k ) of the objective function based on the current parameters. Obtain the partial derivative matrix J of the residual with respect to the parameters by numerical differentiation or analytical method. Calculate the step size Δθ according to the iteration formula, and update θ k+1 = θ k + Δθ;; If the decrease rate ρ of the sum of squared residuals < ε (such as ε = 1e-6), stop the iteration.

[0119] Preferably, the fitting calculation formulas of ice-wind load, ice-covered conductor tension, and tower stress include:

[0120] (1) The fitting formula for the conductor tension is:

[0121]

[0122] Among them, T eq is the equivalent axis tension after correcting the initial static tension of the conductor, h is the ice coating thickness, D is the conductor diameter, ρ ice is the ice density, U is the wind speed, and L is the conductor span.

[0123] (2) The tower stress fitting formula is:

[0124]

[0125] α i is the suspension point inclination angle, θ i is the wind deflection angle, η ice = 1 + 0.015h, which is the ice coating correction, η wind = 1 + 0.01U 2 , which is the wind load correction.

[0126] It should be noted that the present invention combines a variety of theories and algorithms to establish a more accurate calculation model for ice-wind load, ice-coated conductor tension, and tower stress, which can quickly calculate the conductor tension and tower stress under different working conditions, overcome the problem of slow traditional simulation calculation speed, improve the calculation accuracy at the same time, facilitate the staff to timely master the line stress situation, quickly make decisions, and effectively prevent line failures;

[0127] Considering the dynamic interaction between the conductor and the tower (such as the tower vibration transmission effect caused by conductor galloping), the present invention combines the dynamic characteristics of conductor galloping, quantifies the transmission path of conductor tension to tower stress through the tower node stress transfer equation, realizes the collaborative calculation of conductor dynamic tension and tower stress, and improves the power grid disaster resistance ability through real-time data input and risk warning.

[0128] S5: Obtain real-time meteorological data and ice coating monitoring data, input relevant parameters into the ice-coated conductor tension and tower stress calculation model to obtain the calculation results of conductor tension and tower stress, and take corresponding warning measures according to the preset risk level corresponding to the calculation results.

[0129] Preferably, in the S5, the real-time meteorological data includes temperature, wind speed, and precipitation intensity, and the ice coating monitoring data is obtained through an ice coating monitoring device.

[0130] Preferably, the relevant parameters input into the ice-coated conductor tension and tower stress calculation model include: predicted wind speed U (m / s) in the next 72 hours, real-time monitored equivalent ice coating thickness h (mm), ice density ρ ice (kg / m 3 ), conductor span L (m), suspension point inclination angle α i and initial static tension T0.

[0131] Preferably, the corresponding early warning measures are taken according to the preset risk level corresponding to the calculation result as shown in Table 4:

[0132] Table 4 Risk level classification

[0133]

[0134] It should be noted that in view of the problem in the prior art that only focuses on the calculation of wire tension and does not systematically evaluate the mechanical response of the tower, making it difficult to comprehensively ensure the safety of the power transmission system, the present invention proposes a dynamic tension calculation model under the combined action of ice-wind loads. By combining the equivalent density method and the modal perturbation method, it quantifies the non-linear influence of conductor galloping on tension, realizes the real-time coupling analysis of ice load and wind load, improves the calculation accuracy, and provides direct guidance for operation and maintenance through risk level classification, which can more comprehensively ensure the safety of the power transmission system.

[0135] In Embodiment 2 of the present invention, a calculation system for the dynamic tension of an ice-covered conductor galloping and the stress of a tower is provided. Based on the calculation method for the dynamic tension of an ice-covered conductor galloping and the stress of a tower described in Embodiment 1, the system includes:

[0136] A model establishment module, which respectively constructs models of a transmission tower, a conductor, and an insulator using engineering modeling software, and combines them into a conductor-tower system;

[0137] An ice load application module, which calculates the equivalent density of each structure in the ice-covered state, imports it into the modeling software to update the material properties, and constructs an ice-covered equivalent model;

[0138] A wind load application module, which applies wind load to the ice-covered equivalent model of the transmission line-tower system;

[0139] A calculation and modeling module, which calculates the dynamic tension of the conductor and the stress of the tower under different ice and wind loads, fits the calculation formula, and constructs a calculation model;

[0140] A data processing and early warning module, which obtains real-time meteorological and ice-covered monitoring data, inputs them into the calculation model, and takes early warning measures according to the risk level corresponding to the calculation result.

[0141] The present disclosure may be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to implement various aspects of the present disclosure.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A calculation method for the dynamic tension of an ice-covered conductor and the stress of a pole tower, characterized in that, It includes the following steps: Establish models of transmission towers, conductors and insulators, and form a conductor-tower system; Apply ice loads to the conductor-tower system by changing the density, including: calculating the equivalent density of the transmission conductors, towers and insulators under the ice-covered state to update the material property parameters of the corresponding components, and constructing an equivalent ice-covered model of the transmission conductors, towers and insulators; Assemble the equivalent ice-covered models of the transmission towers, insulators and conductors to construct an equivalent ice-covered model of the transmission line-tower system, and apply wind loads to the transmission conductors and towers; Repeat the above steps, calculate the dynamic tension of the ice-covered conductors and the stress of the transmission towers under different ice loads and wind loads, respectively fit the calculation formulas of ice-wind loads and the tension of the ice-covered conductors and the stress of the towers, and construct a calculation model for the tension of the ice-covered conductors and the stress of the towers; Obtain real-time meteorological data and ice-covered monitoring data, and input relevant parameters into the calculation model for the tension of the ice-covered conductors and the stress of the towers to obtain the calculation results of the conductor tension and the tower stress.

2. A method for calculating the dynamic tension of ice-covered conductor galloping and the stress of towers according to claim 1, characterized in that: Applying wind loads to the transmission conductors and towers in the equivalent ice-covered model of the transmission line-tower system includes: Applying wind loads to the transmission conductors and towers using the resistance coefficient of the ice-covered conductors, the wind load adjustment coefficients of the conductors and towers, the calculated outer diameter of the conductors after ice covering, and the shape coefficients of the conductors and towers during ice covering. The wind loads include the reference wind pressure, the wind pressure height change coefficient, the wind load shape coefficient and the wind load adjustment coefficient.

3. A method for calculating the dynamic tension of ice-covered conductor galloping and the stress of towers according to claim 2, characterized in that: Calculating the wind load per unit length of the ice-covered conductor includes: The wind load per unit length of the ice-covered conductor is the product of the wind pressure non-uniformity coefficient, the standard value of the reference wind pressure, the wind pressure height change coefficient, the resistance coefficient of the ice-covered conductor, the wind load adjustment coefficient of the ice-covered conductor, the calculated outer diameter of the conductor after ice covering, and the square of the sine value of the angle between the horizontal wind and the line direction; Calculating the wind load per unit length of the ice-covered tower includes: The wind load per unit length of the ice-covered tower is the product of the wind load adjustment coefficient of the tower, the standard value of the reference wind pressure, the wind pressure height change coefficient, the shape coefficient of the conductor, the shape coefficient of the tower, and the calculated outer diameter of the conductor after ice covering.

4. A method for calculating the dynamic tension of ice-covered conductor galloping and the stress of towers according to claim 3, characterized in that: The calculation of the dynamic tension of the ice-covered conductor under different ice loads and wind loads includes: Correcting the static tension of the conductor: Wherein, T0 is the initial static tension of the conductor, E is the comprehensive elastic modulus, A is the cross-sectional area of the conductor, Δl is the change in the length of the conductor caused by galloping, β′ is the elevation angle of the wind deviation plane, θ is the torsion angle of the conductor, and φ is the wind deviation angle; Combined with modal perturbation, establish a non-linear relationship between ice-wind loads and the dynamic tension of the ice-covered conductor; T d = T eq + k1·(γ ice ·d ice ) 0.8 + k2·(ρ air ·U 2 ·C d ·D eq ) 1.2 Among them, T eq is the equivalent axis tension after correcting the initial static tension of the conductor, γ ice is the ice load specific gravity, d ice is the ice coating thickness, U is the wind speed, C d is the aerodynamic drag coefficient, D eq is the equivalent diameter of the conductor, ρ air is the air density, k1 is the steady-state aerodynamic correction coefficient; k2 is the dynamic turbulence correction coefficient.

5. A method for calculating the dynamic tension of ice-covered conductor galloping and the stress of towers according to claim 4, characterized in that: The calculation of the stress of the transmission tower under different ice loads and wind loads includes: Construct a stress transfer equation for the tower nodes: Among them, L i is the span of the conductor, α i is the inclination angle of the suspension point, A tower is the cross-sectional area of the tower member, Z is the section modulus, η damp is the damping correction coefficient, T d,i is the dynamic tension of the i-th span of the conductor.

6. The calculation method for the dynamic tension of an ice-covered conductor and the stress of a transmission tower according to claim 5, characterized in that: The calculation formulas for fitting the ice-wind load, the tension of the ice-covered conductor, and the stress of the transmission tower include: Based on the calculation results and simulation result data of the dynamic tension of the ice-covered conductor and the stress of the transmission tower under different ice loads and wind loads, a data set of the peak dynamic tension of the ice-covered conductor and the stress of the key nodes of the transmission tower is constructed; Using the Levenberg-Marquardt algorithm to optimize the parameters of the non-linear relationship between the ice-wind load and the dynamic tension and the stress transfer equation of the transmission tower nodes, and its objective function is: Among them, T d,calc is the calculated value of the dynamic tension of the conductor, and T d,sim is the simulated value of the conductor tension. σ calc is the calculated value of the stress of the tower pole node, and σ sim is the simulated value of the stress of the tower pole node.

7. The calculation method for the dynamic tension of an ice-covered conductor and the stress of a transmission tower according to claim 6, characterized in that: The fitting formulas for the ice-wind load, the tension of the ice-covered conductor, and the stress of the transmission tower obtained by optimization include: The fitting formula for the ice-wind load and the tension of the ice-covered conductor is: Among them, T eq is the equivalent axis tension after correcting the initial static tension T0 of the conductor, h is the ice coating thickness, D is the conductor diameter, ρ ice is the ice density, U is the wind speed, and L is the conductor span; The fitting formula for the ice-wind load and the stress of the transmission tower is: α i is the suspension point dip angle, θ i is the wind deflection angle, η ice is the ice coating correction, η wind is the wind load correction.

8. The calculation method for the dynamic tension of an ice-covered conductor and the stress of a transmission tower according to claim 7, characterized in that: The relevant parameters input into the calculation model of the tension of the ice-covered conductor and the stress of the transmission tower include: the predicted wind speed in the next 72 hours, the real-time monitored equivalent ice thickness, the ice density, the conductor span, the suspension angle, and the initial static tension.

9. The calculation method for the dynamic tension of an ice-covered conductor and the stress of a transmission tower according to claim 8, characterized in that: Obtaining the tension of the ice-covered conductor and the stress of the transmission tower further includes taking corresponding early warning measures according to the preset risk level corresponding to the calculation results, including: The preset risk levels include the normal level, the attention level, and the early warning level; The dynamic tension threshold corresponding to the normal level is Td < 0.5T max , and the tower stress threshold is σ < 0.6σ y , and the warning measure is to maintain routine monitoring; The dynamic tension threshold corresponding to the attention level is 0.5T max ≤Td<0.8T max The tower stress threshold is 0.6σ y ≤σ<0.8σ y The warning measures are to start the drone inspection and increase the monitoring frequency; The dynamic tension threshold corresponding to the warning level is Td≥0.8T max , and the tower stress threshold is σ≥0.8σ y , and the warning measures are to start DC de-icing, mechanical de-icing or tension adjustment; Among them, T max is the peak value of the dynamic tension of the ice-covered conductor, and σ y is the yield stress of the tower material.

10. A calculation system for dynamic tension of ice-covered conductor galloping and tower stress, based on the calculation method for dynamic tension of ice-covered conductor galloping and tower stress described in claims 1-9, characterized in that, The system includes: A model establishment module, used to construct models of transmission towers, conductors, and insulators, and combine them into a conductor-tower system; An ice load application module, which calculates the equivalent density of each structure under the ice-covered state, updates the material properties of the corresponding components, and constructs an ice-covered equivalent model; A wind load application module, which applies wind loads to the ice-covered equivalent model of the transmission line-tower system; A calculation and modeling module, which calculates the dynamic tension of the conductor and the stress of the transmission tower under different ice and wind loads, fits the calculation formulas, and constructs a calculation model; A data processing module, which obtains real-time meteorological and ice-covered monitoring data, inputs them into the calculation model, and obtains the calculation results of the tension of the ice-covered conductor and the stress of the transmission tower.

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