Method and system for safety evaluation of power transmission tower and conductor under avalanche-air blast action

Abstract

The application provides a kind of avalanche-air wave under the action of power transmission tower and conductor safety evaluation method and system, belongs to power transmission engineering technical field.The application is equivalent to the multi-degree-of-freedom cantilever beam structure of power transmission tower, and is equivalent to the catenary structure of conductor, according to the spatial relationship between avalanche core and impact air wave and power transmission system, two working conditions of power transmission tower directly affected by disaster and conductor affected by disaster are divided;based on the dynamic parameters obtained by avalanche-air wave motion simulation, in the working condition of power transmission tower directly affected by disaster, it is applied to power transmission tower model as load to carry out dynamic response analysis to evaluate safety;in the working condition of conductor affected by disaster, it is applied to conductor model as excitation to solve conductor response and tension, and the tension is transmitted to the tower body to evaluate the overall safety of tower line.The application realizes the comprehensive evaluation of the safety state of power transmission system under the action of avalanche-air wave, and provides technical support for the planning and design of power transmission line in avalanche-prone area and protection.

Description

Technical Field

[0001] This invention belongs to the field of power transmission engineering technology, specifically relating to a method and system for safety assessment of transmission towers and conductors under avalanche-wave action. Background Technology

[0002] Avalanche disasters are widely distributed in high-altitude and cold mountainous areas, typically manifesting as a complex disaster process involving a dense avalanche core and accompanying shock waves. The shock waves can generate significant transient impact loads over a considerable height range, extending far beyond the avalanche accumulation zone and posing a potential threat to tall structures and linear engineering facilities. With the continuous expansion of power transmission lines in high-altitude and cold mountainous areas, avalanche disasters have become one of the important factors affecting the safe operation of power transmission systems.

[0003] Transmission lines typically avoid direct impact from avalanche nuclei on transmission towers through strategic site selection; however, conductors inevitably cross avalanche paths. When an avalanche occurs, the shockwave can act on the conductors, causing significant swaying and a sudden increase in tension, which in turn transmits the tension to the transmission tower, leading to failure modes such as tower overturning, component damage, or foundation failure. Related engineering practice shows that some transmission towers are not directly damaged by avalanche impacts, but rather fail due to the dynamic tension of the conductors.

[0004] Current research and engineering applications primarily focus on safety assessments of transmission lines under typical power conditions such as wind load, icing, and line breaks. Research on avalanche disasters mainly emphasizes macro-level aspects such as avalanche path identification, hazard zoning, and tower relocation. There is a lack of systematic and unified engineering assessment methods for the dynamic response characteristics of avalanche cores and shock waves on transmission towers, as well as the dynamic mechanisms by which shock waves affect conductors and transmit tension, impacting tower safety. Existing methods often employ equivalent static loads or simplified wind loads, which fail to reflect the short-term pulse characteristics and dynamic amplification effects under avalanche and shock wave conditions. Summary of the Invention

[0005] This invention provides a method and system for safety assessment of transmission towers and conductors under avalanche-shock wave action. By distinguishing between the different scenarios of avalanches directly acting on transmission towers and shock waves acting on conductors and transmitting to transmission towers, a corresponding dynamic analysis model is established. Based on the prediction results of the avalanche and shock wave motion processes, the stress state and response characteristics of the transmission tower and conductor system under avalanche-shock wave action are analyzed, enabling a quantitative assessment of the structural safety risks of transmission lines. This provides a scientific basis for the route selection optimization, operation and maintenance, and protection engineering design of transmission lines in high-altitude and cold mountainous areas, thereby effectively solving at least one of the technical problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0007] A method for safety assessment of transmission towers and conductors under avalanche-wave action includes the following steps:

[0008] Step S1: Obtain topographic data of the study area and engineering parameters of the transmission lines, and establish a three-dimensional computational domain that includes the location of transmission towers, spatial distribution of conductors, and topographic features;

[0009] Step S2: Equivalently model the transmission tower as a multi-degree-of-freedom cantilever beam structure and establish a dynamic model of the transmission tower; equivalently model the conductor as a catenary structure and establish dynamic control equations.

[0010] Step S3: A two-layer depth-averaged model is used to simulate the motion process of the avalanche core and the induced shock wave, and to calculate the dynamic characteristic parameters of the avalanche core and the shock wave during the motion process.

[0011] Step S4: Based on the spatial relative position of the avalanche core and shock wave with the power transmission system, the disaster impact conditions are divided into two categories: direct damage to the transmission towers and damage to the conductors. Safety assessments are then conducted for each of these two categories.

[0012] Under the direct disaster conditions of the transmission tower, the dynamic characteristic parameters of the avalanche core and the impact wave obtained in step S3 are equivalent to the time-varying external load and applied to the transmission tower dynamic model established in step S2. By performing modal analysis and dynamic response calculation on the transmission tower, its vibration response, internal force evolution and deformation failure characteristics are obtained, and the safety of the transmission tower is evaluated accordingly.

[0013] Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed along the conductor space and applied to the conductor dynamic control equation established in step S2. The dynamic response of the conductor under the action of the impact wave is solved to obtain its reciprocating swing amplitude, axial tensile deformation and tension change, thereby assessing the safety of the conductor. At the same time, the tension change of the conductor is transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. The vibration response, internal force evolution and deformation failure characteristics of the transmission tower under the condition of conductor damage are analyzed, thereby assessing the safety of the transmission tower.

[0014] As a preferred improvement, the engineering parameters of the transmission line include the spatial location of the transmission tower, the tower structure, the tower height, the component arrangement and mass distribution parameters, as well as the span length, suspension type, initial tension, conductor diameter and mass per unit length of the transmission line.

[0015] As a preferred improvement, the terrain data is derived from the digital elevation model data of the study area, and the engineering parameters of the transmission line are derived from the engineering design data of the transmission line.

[0016] As a preferred improvement, the transmission tower in the first The equations of motion for the first mode are expressed as:

[0017]

[0018] In the formula, Quality in a broad sense; For generalized stiffness; For generalized displacement, For generalized load; It is the structural vibration mode; This is the quality distribution matrix; This is the stiffness distribution matrix; This is the load distribution matrix; For resistance, this represents the damping ratio corresponding to each vibration mode; For time.

[0019] As a preferred improvement, the dynamic governing equations of the conductor include axial displacement equations, horizontal displacement equations, and vertical displacement equations, which are expressed as follows:

[0020] The equation for axial displacement is:

[0021]

[0022] In the formula, This represents the axial displacement of the conductor. This represents the horizontal displacement of the conductor. Vertical displacement of the conductor, For axial wave velocity, For elastic modulus, The cross-sectional area of ​​the conductor is... Mass per unit length of the conductor; Represents the spatial coordinates along the axis of the conductor;

[0023] The equation for horizontal displacement is:

[0024]

[0025] In the formula, This is an externally applied dynamic excitation term in the horizontal direction;

[0026] The vertical displacement equation is:

[0027]

[0028] In the formula, This is a vertical external dynamic excitation term.

[0029] As a preferred improvement, in step S3, the double-layer depth averaging model is selected as the avalanche dynamics analysis software RAMMS-Extended.

[0030] As a preferred improvement, in step S3, the dynamic characteristic parameters of the avalanche core and the impact wave during the motion process include the velocity field, pressure distribution, range of action, and duration of action.

[0031] As a preferred improvement, the classification of disaster-affected working conditions is based on:

[0032] (1) Direct disaster conditions of transmission towers: The transmission towers are located in the avalanche channel, and the avalanche core and the shock wave act on the transmission towers at the same time.

[0033] (2) Damaged conductor: The transmission tower is located on both sides of the avalanche channel. The avalanche core does not directly affect the transmission tower. Only the impact wave affects the conductor crossing the avalanche channel and transmits the power to the transmission tower through the conductor.

[0034] A system for performing the above-described safety assessment method for transmission towers and conductors under avalanche-wave action includes:

[0035] The computational domain construction module is used to acquire topographic data of the study area and engineering parameters of transmission lines, and to establish a three-dimensional computational domain that includes the location of transmission towers, spatial distribution of conductors and topographic features.

[0036] The dynamic modeling module is used to model the transmission tower as a multi-degree-of-freedom cantilever beam structure and establish a dynamic model of the transmission tower; and to model the conductor as a catenary structure and establish dynamic control equations.

[0037] The avalanche simulation module is used to simulate the motion process of the avalanche core and the induced shock wave using a two-layer depth averaging model, and to calculate the dynamic characteristic parameters of the avalanche core and the shock wave during the motion process.

[0038] The assessment module, based on the spatial relative position of the avalanche core and shockwave with the power transmission system, classifies the disaster impact conditions into two categories: direct damage to transmission towers and damage to conductors. Safety assessments are then conducted for each of these two categories.

[0039] Under the direct disaster conditions of the transmission tower, the dynamic characteristic parameters of the avalanche core and the impact wave obtained in step S3 are equivalent to the time-varying external load and applied to the transmission tower dynamic model established in step S2. By performing modal analysis and dynamic response calculation on the transmission tower, its vibration response, internal force evolution and deformation failure characteristics are obtained, and the safety of the transmission tower is evaluated accordingly.

[0040] Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed along the conductor space and applied to the conductor dynamic control equation established in step S2. The dynamic response of the conductor under the action of the impact wave is solved to obtain its reciprocating swing amplitude, axial tensile deformation and tension change, thereby assessing the safety of the conductor. At the same time, the tension change of the conductor is transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. The vibration response, internal force evolution and deformation failure characteristics of the transmission tower under the condition of conductor damage are analyzed, thereby assessing the safety of the transmission tower.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) This invention takes the avalanche core and the impact wave it induces as the external dynamic load source, and systematically introduces the dynamic analysis framework of the transmission tower and the conductor. It breaks through the traditional method of relying on experience judgment or static simplification, and realizes the quantitative prediction of structural safety risks.

[0043] (2) The present invention clearly divides two typical working conditions according to the disaster action mode and establishes targeted analysis paths for each, avoiding the error caused by mixed evaluation and more accurately characterizing the failure modes under different scenarios.

[0044] (3) The present invention uses a multi-degree-of-freedom model and a catenary model to describe the dynamic behavior of the tower and the line respectively, which overcomes the shortcomings of ignoring dynamic effects or using equivalent static load, and improves the physical rationality and engineering reliability of the calculation results.

[0045] (4) This invention reveals the indirect failure mechanism of “conductor damage - tension transmission - tower failure”, which effectively makes up for the shortcomings of the existing technology in not considering the coupling effect of conductor-tower, and provides a new perspective for comprehensively evaluating the safety of power transmission system.

[0046] (5) This invention takes the avalanche-air wave motion simulation results as input and can be directly coupled with existing avalanche numerical simulation technology, which has good versatility and engineering applicability. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0048] Figure 1 This is a flowchart illustrating the safety assessment method for transmission towers and conductors under avalanche-wave action provided by the present invention.

[0049] Figure 2 This is a schematic diagram of the three-dimensional computational domain geometric model provided in Embodiment 1 of the present invention;

[0050] Figure 3 This is a diagram showing the calculation results of the conductor load in Embodiment 1 of the present invention. Detailed Implementation

[0051] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] like Figure 1 As shown, this embodiment provides a method for safety assessment of transmission towers and conductors under avalanche-wave action, including the following steps:

[0053] Step S1: Obtain topographic data of the study area and engineering parameters of the transmission lines, and establish a three-dimensional computational domain that includes the location of transmission towers, spatial distribution of conductors, and topographic features.

[0054] Obtain digital elevation model (DEM) data for the study area and design data for the transmission line engineering to be evaluated. Extract key engineering parameters from the design data, including: latitude and longitude coordinates of each transmission tower, tower type (e.g., cat-head tower, goblet tower), total height, segment height, cross-sectional dimensions and materials of main and auxiliary materials for each segment (for calculating mass distribution and equivalent stiffness), conductor type, diameter, mass per unit length, modulus of elasticity, initial installation tension, span, and suspension point height, etc.

[0055] Based on the aforementioned terrain and engineering data, a three-dimensional computational domain geometric model is established using CAD or CAE preprocessing software. This model includes the actual terrain surface, the location and orientation of the transmission towers, and the three-dimensional spatial shape of the conductors (calculated according to the catenary equation). This provides a unified spatial framework for subsequent disaster simulation and structural analysis.

[0056] Step S2: Equivalently model the transmission tower as a multi-degree-of-freedom cantilever beam structure and establish a dynamic model of the transmission tower; equivalently model the conductor as a catenary structure and establish dynamic control equations.

[0057] The transmission tower is equivalent to a multi-degree-of-freedom cantilever beam structure. Based on the structural characteristics of the transmission tower, the tower body is segmented and discretized to determine the mass distribution, equivalent stiffness, and damping parameters of each discrete element, thus establishing a dynamic model of the transmission tower.

[0058] The transmission tower is at the The equations of motion for the first mode are expressed as:

[0059]

[0060] In the formula, Quality in a broad sense; For generalized stiffness; For generalized displacement, For generalized load; It is the structural vibration mode; This is the quality distribution matrix; This is the stiffness distribution matrix; This is the load distribution matrix; For resistance, this represents the damping ratio corresponding to each vibration mode; Indicates time.

[0061] The conductor is equivalent to a catenary structure, and its dynamic governing equations are established along the length of the conductor. The conductor motion is decomposed along the axial, horizontal, and vertical directions, where the axial displacement, horizontal displacement, and vertical displacement are described by the corresponding dynamic governing equations, which are used to characterize the oscillation, stretching, and tension evolution of the conductor under the action of external forces.

[0062] The equation for axial displacement is:

[0063]

[0064] In the formula, This represents the axial displacement of the conductor. This represents the horizontal displacement of the conductor. Vertical displacement of the conductor, For axial wave velocity, For elastic modulus, The cross-sectional area of ​​the conductor is... Mass per unit length of the conductor; This represents the spatial coordinates along the axis of the conductor.

[0065] The equation for horizontal displacement is:

[0066]

[0067] In the formula, It is an external dynamic excitation term in the horizontal direction.

[0068] The vertical displacement equation is:

[0069]

[0070] In the formula, This is a vertical external dynamic excitation term.

[0071] Step S3: A two-layer depth-averaged model is used to simulate the motion process of the avalanche core and the induced shock wave, and to calculate the dynamic characteristic parameters of the avalanche core and the shock wave during the motion process.

[0072] The dynamic characteristics of avalanche-impact shockwaves were calculated using the avalanche dynamic analysis software RAMMS-Extended. The calculation process can be performed using conventional techniques in this field, and will not be elaborated upon in this implementation. The dynamic characteristic parameters of the avalanche core and impact shockwaves during their movement include velocity field, pressure distribution, range of action, and duration of action, which are used to quantify the intensity and time history of the disaster's impact on the structure.

[0073] The initial release zone location, volume, and physicomechanical parameters (such as internal friction angle and bottom friction coefficient) of the avalanche are defined. The entire process of an avalanche, from initiation and movement to deposition, is simulated through numerical solutions. The simulation results will output a series of spatiotemporal data:

[0074] Velocity field: The distribution of the velocity vectors of the avalanche core and air within the computational domain and their variation over time;

[0075] Pressure distribution: the impact pressure of the avalanche core on the ground, and the dynamic and static pressure time histories of the impact wave at various points in space;

[0076] Scope of effect: The boundary of the avalanche core flow (avalanche channel) and the pressure influence range of the impact wave;

[0077] Action time history: The complete history curve of pressure and velocity changes over time at the location of the transmission tower or conductor.

[0078] Step S4: Based on the spatial relative position of the avalanche core and shock wave with the power transmission system, the disaster impact conditions are divided into two categories: direct damage to the transmission towers and damage to the conductors. Safety assessments are then conducted for each of these two categories.

[0079] Under the direct disaster conditions of the transmission tower, the dynamic characteristic parameters of the avalanche core and the impact wave obtained in step S3 are equivalent to the time-varying external load and applied to the transmission tower dynamic model established in step S2. By performing modal analysis and dynamic response calculation on the transmission tower, its vibration response, internal force evolution and deformation failure characteristics are obtained, and the safety of the transmission tower is evaluated accordingly.

[0080] Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed along the conductor space and applied to the conductor dynamic control equation established in step S2. The dynamic response of the conductor under the action of the impact wave is solved to obtain its reciprocating swing amplitude, axial tensile deformation and tension change, thereby assessing the safety of the conductor. At the same time, the tension change of the conductor is transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. The vibration response, internal force evolution and deformation failure characteristics of the transmission tower under the condition of conductor damage are analyzed, thereby assessing the safety of the transmission tower.

[0081] The maximum impact range of the avalanche core and the pressure field of the shock wave obtained in step S3 are superimposed with the spatial positions of the transmission towers and conductors in step S1 for analysis:

[0082] If a power transmission tower is located within the flow path (avalanche channel) of the avalanche core, then the tower is determined to be in a "directly affected power transmission tower condition".

[0083] If all transmission towers are located outside the avalanche path, but a conductor crosses the avalanche path and is within the impact range of the shock wave, then the system is determined to be in a "conductor disaster condition".

[0084] Under the condition of direct damage to the transmission tower, the dynamic characteristic parameters of the avalanche core and the shock wave obtained in step S3 are equivalent to time-varying external loads. The dynamic model of the transmission tower established in step S2 is applied, and its vibration response, internal force evolution and deformation characteristics are obtained by performing modal analysis and dynamic response calculation on the transmission tower. Based on the material strength and structural deformation requirements, the safety of the transmission tower is evaluated.

[0085] Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed spatially along the conductor. and The dynamic control equations for the conductor established in step S2 are applied to obtain the conductor's reciprocating oscillation amplitude, axial tensile deformation, and tension changes by solving the conductor's dynamic response under the impact blast wave. Based on the material strength threshold, the safety of the conductor is assessed. Simultaneously, the tension changes of the conductor are transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. This study analyzes the vibration response, internal force evolution, and deformation and failure characteristics of the transmission tower under conductor disaster conditions, applying concentrated forces to the tower-conductor connection. Based on the tower material strength and structural deformation requirements, the safety of the transmission tower is assessed. Specifically:

[0086] (1) For the direct disaster-affected conditions of the transmission tower: The dynamic characteristic parameters of the avalanche core and impact wave obtained in step S3, especially the pressure time history on the structural surface, are converted into time-varying external dynamic loads and applied to the corresponding nodes of the multi-degree-of-freedom cantilever beam structural model of the transmission tower established in step S2. Subsequently, modal analysis is performed on the model to obtain its dynamic characteristics, and dynamic time history analysis is performed to calculate its displacement, velocity, and acceleration response under external loads, as well as the evolution process of internal forces (such as axial force, bending moment, and shear force) of each component. By comparing the calculated internal forces with the component strength and stability bearing capacity, the overall instability or local failure of the transmission tower under this condition is evaluated, and its potential failure modes are identified.

[0087] (2) For the conductor under disaster conditions: The velocity field and pressure distribution of the impact wave obtained in step S3 are transformed into external dynamic excitation terms distributed along the length of the conductor and applied to the catenary dynamic model of the conductor established in step S2. By solving the dynamic response equations, the time history response of the conductor under the impact of the impact wave is obtained, including the reciprocating swing amplitude, axial tensile deformation, and the dynamic change process of tension. Furthermore, the tension change at both ends of the conductor is treated as a dynamic concentrated load that varies with time and is applied to the dynamic model of the transmission tower through the connection node between the conductor and the transmission tower. By re-analyzing the transmission tower model, its stress and deformation characteristics under the dynamic load of the node are calculated to assess whether the conductor will break and whether the transmission tower will overturn, yield, or fail at the connection node under the tensile force transmitted by the conductor.

[0088] Finally, by combining the evaluation results under the two working conditions, key indicators such as the displacement at the top of the transmission tower, the stress ratio of critical components, the maximum tension of the conductor, and the load of the connection node are selected to comprehensively determine the overall safety status of the transmission tower and conductor system, and identify the possible failure modes of the transmission system, thereby completing the quantitative assessment of the structural safety risk of the transmission line under avalanche-wave action.

[0089] This embodiment also provides a system for performing the above-described method for safety assessment of transmission towers and conductors under avalanche-wave action, comprising:

[0090] The computational domain construction module is used to acquire topographic data of the study area and engineering parameters of transmission lines, and to establish a three-dimensional computational domain that includes the location of transmission towers, spatial distribution of conductors and topographic features.

[0091] The dynamic modeling module is used to model the transmission tower as a multi-degree-of-freedom cantilever beam structure and establish a dynamic model of the transmission tower; and to model the conductor as a catenary structure and establish dynamic control equations.

[0092] The avalanche simulation module is used to simulate the motion process of the avalanche core and the induced shock wave using a two-layer depth averaging model, and to calculate the dynamic characteristic parameters of the avalanche core and the shock wave during the motion process.

[0093] The assessment module, based on the spatial relative position of the avalanche core and shockwave with the power transmission system, classifies the disaster impact conditions into two categories: direct damage to transmission towers and damage to conductors. Safety assessments are then conducted for each of these two categories.

[0094] Under the direct disaster conditions of the transmission tower, the dynamic characteristic parameters of the avalanche core and the impact wave obtained in step S3 are equivalent to the time-varying external load and applied to the transmission tower dynamic model established in step S2. By performing modal analysis and dynamic response calculation on the transmission tower, its vibration response, internal force evolution and deformation failure characteristics are obtained, and the safety of the transmission tower is evaluated accordingly.

[0095] Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed along the conductor space and applied to the conductor dynamic control equation established in step S2. The dynamic response of the conductor under the action of the impact wave is solved to obtain its reciprocating swing amplitude, axial tensile deformation and tension change, thereby assessing the safety of the conductor. At the same time, the tension change of the conductor is transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. The vibration response, internal force evolution and deformation failure characteristics of the transmission tower under the condition of conductor damage are analyzed, thereby assessing the safety of the transmission tower.

[0096] Example 1

[0097] To verify the effectiveness of this invention, this embodiment selects a power transmission line in a high-altitude, cold region as the research object. In this transmission line, the transmission towers are 20m high, in the form of cat-head towers, with a material elastic modulus of 200 GPa and a material density of 8000 kg / m³. 3 The mass per unit height is 550 kg / m; the conductor cross-sectional area is 907 mm². 2 The unit length mass is 1.8 kg / m, the elastic modulus is 100 GPa, the suspension point height is 16 m above the ground, and the initial installation tension is 12 kN. Based on the above parameters, a three-dimensional computational domain geometric model is established using CAE software as follows: Figure 2 As shown, a dynamic model of the transmission tower and dynamic control equations of the conductor are constructed.

[0098] The avalanche-impact wave dynamics characteristics were calculated using the avalanche dynamic analysis software RAMMS-Extended. During the calculation, the avalanche initiation volume was set to 58900 m³. 3 .

[0099] Analysis of historical avalanche monitoring data revealed that the main occurrence in this area was conductor damage. Avalanches crossed the trench between two transmission towers, and the resulting shockwaves acted on the conductors, causing them to sway and break. The conductor load calculation results obtained through dynamic analysis are as follows: Figure 3 As shown, the calculation results are compared with the monitoring results, verifying the reliability of the calculation results in this embodiment.

[0100] The embodiments of the present invention have been described above, but the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit of the present invention, and all of these forms are within the protection scope of the present invention.

Claims

1. A method for safety assessment of transmission towers and conductors under avalanche-wave action, characterized in that, Includes the following steps: Step S1: Obtain topographic data of the study area and engineering parameters of the transmission lines, and establish a three-dimensional computational domain that includes the location of transmission towers, spatial distribution of conductors, and topographic features; Step S2: Equivalently model the transmission tower as a multi-degree-of-freedom cantilever beam structure and establish a dynamic model of the transmission tower; equivalently model the conductor as a catenary structure and establish dynamic control equations. Step S3: A two-layer depth-averaged model is used to simulate the motion process of the avalanche core and the induced shock wave, and to calculate the dynamic characteristic parameters of the avalanche core and the shock wave during the motion process. Step S4: Based on the spatial relative position of the avalanche core and shock wave with the power transmission system, the disaster impact conditions are divided into two categories: direct damage to the transmission towers and damage to the conductors. Safety assessments are then conducted for each of these two categories. Under the direct disaster conditions of the transmission tower, the dynamic characteristic parameters of the avalanche core and the impact wave obtained in step S3 are equivalent to the time-varying external load and applied to the transmission tower dynamic model established in step S2. By performing modal analysis and dynamic response calculation on the transmission tower, its vibration response, internal force evolution and deformation failure characteristics are obtained, and the safety of the transmission tower is evaluated accordingly. Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed along the conductor space and applied to the conductor dynamic control equation established in step S2. The dynamic response of the conductor under the action of the impact wave is solved to obtain its reciprocating swing amplitude, axial tensile deformation and tension change, thereby assessing the safety of the conductor. At the same time, the tension change of the conductor is transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. The vibration response, internal force evolution and deformation failure characteristics of the transmission tower under the condition of conductor damage are analyzed, thereby assessing the safety of the transmission tower.

2. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, The engineering parameters of the transmission line include the spatial location of the transmission tower, the tower structure, the tower height, the component layout and mass distribution parameters, as well as the span length, suspension type, initial tension, conductor diameter and mass per unit length of the transmission line.

3. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, The terrain data is derived from the digital elevation model data of the study area, and the engineering parameters of the transmission line are derived from the engineering design data of the transmission line.

4. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, The transmission tower is at the The equations of motion for the first mode are expressed as: In the formula, Quality in a broad sense; For generalized stiffness; For generalized displacement, For generalized load; It is the structural vibration mode; This is the quality distribution matrix; This is the stiffness distribution matrix; This is the load distribution matrix; For resistance, this represents the damping ratio corresponding to each vibration mode; For time.

5. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, The dynamic governing equations of the conductor include the axial displacement equation, the horizontal displacement equation, and the vertical displacement equation, which are expressed as follows: The equation for axial displacement is: In the formula, This represents the axial displacement of the conductor. This represents the horizontal displacement of the conductor. This represents the vertical displacement of the conductor. For axial wave velocity, For elastic modulus, The cross-sectional area of ​​the conductor is... Mass per unit length of the conductor; Represents the spatial coordinates along the axis of the conductor; The equation for horizontal displacement is: In the formula, This is an externally applied dynamic excitation term in the horizontal direction; The vertical displacement equation is: In the formula, This is a vertical external dynamic excitation term.

6. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, In step S3, the double-layer depth averaging model is selected as the avalanche dynamic analysis software RAMMS-Extended.

7. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, In step S3, the dynamic characteristic parameters of the avalanche core and the impact wave during their motion include the velocity field, pressure distribution, range of action, and duration of action.

8. The method for safety assessment of transmission towers and conductors under avalanche-wave action according to claim 1, characterized in that, The criteria for classifying disaster-affected working conditions are as follows: (1) Direct disaster conditions of transmission towers: The transmission towers are located in the avalanche channel, and the avalanche core and the shock wave act on the transmission towers at the same time. (2) Damaged conductor: The transmission tower is located on both sides of the avalanche channel. The avalanche core does not directly affect the transmission tower. Only the impact wave affects the conductor crossing the avalanche channel and transmits the power to the transmission tower through the conductor.

9. A system for performing the safety assessment method for transmission towers and conductors under avalanche-blast wave action as described in any one of claims 1-8, characterized in that, include: The computational domain construction module is used to acquire topographic data of the study area and engineering parameters of transmission lines, and to establish a three-dimensional computational domain that includes the location of transmission towers, spatial distribution of conductors and topographic features. The dynamic modeling module is used to model the transmission tower as a multi-degree-of-freedom cantilever beam structure and establish a dynamic model of the transmission tower; and to model the conductor as a catenary structure and establish dynamic control equations. The avalanche simulation module is used to simulate the motion process of the avalanche core and the induced shock wave using a two-layer depth averaging model, and to calculate the dynamic characteristic parameters of the avalanche core and the shock wave during the motion process. The assessment module, based on the spatial relative position of the avalanche core and shockwave with the power transmission system, classifies the disaster impact conditions into two categories: direct damage to transmission towers and damage to conductors. Safety assessments are then conducted for each of these two categories. Under the direct disaster conditions of the transmission tower, the dynamic characteristic parameters of the avalanche core and the impact wave obtained in step S3 are equivalent to the time-varying external load and applied to the transmission tower dynamic model established in step S2. By performing modal analysis and dynamic response calculation on the transmission tower, its vibration response, internal force evolution and deformation failure characteristics are obtained, and the safety of the transmission tower is evaluated accordingly. Under the condition of conductor damage, the dynamic characteristic parameters of the impact wave calculated in step S3 are transformed into external dynamic excitation terms distributed along the conductor space and applied to the conductor dynamic control equation established in step S2. The dynamic response of the conductor under the action of the impact wave is solved to obtain its reciprocating swing amplitude, axial tensile deformation and tension change, thereby assessing the safety of the conductor. At the same time, the tension change of the conductor is transmitted to the tower body through the connection node between the conductor and the transmission tower as an additional dynamic load. The vibration response, internal force evolution and deformation failure characteristics of the transmission tower under the condition of conductor damage are analyzed, thereby assessing the safety of the transmission tower.

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