Method, device and equipment for evaluating reliability of transmission tower line system and storage medium

Abstract

The application provides a power transmission tower line system reliability evaluation method, device and equipment and a storage medium, relates to the power transmission tower line system disaster resistance analysis and evaluation technical field, and performs probability space profiling on power transmission tower line system structure parameters and disaster parameters to obtain representative point parameter samples; a first finite element analysis model is established according to the representative point parameter samples, time domain dynamic analysis is performed on the first finite element analysis model, and the dynamic response of the power transmission tower line system is obtained; a probability density evolution equation is established according to the dynamic response; the failure probability of the power transmission tower line system under the action of disasters is calculated according to the probability density evolution equation, and the reliability of the power transmission tower line system is obtained according to the correlation between the failure probability and the reliability, so that the reliability of the power transmission tower line system under the action of multiple disasters can be efficiently and accurately evaluated.

Description

Technical Field

[0001] This invention relates to the field of disaster resistance analysis and evaluation technology for power transmission tower systems, and in particular to a method, apparatus, equipment and storage medium for reliability assessment of power transmission tower systems. Background Technology

[0002] Transmission tower systems are a crucial component of power transmission and distribution networks and a vital energy infrastructure vital to national welfare and people's livelihoods. Characterized by their height and long spans, transmission tower systems exhibit significant structural flexibility and are highly susceptible to damage and even collapse under the influence of disasters such as wind and earthquakes, potentially triggering secondary disasters. Therefore, reliability assessment of transmission tower systems under disaster conditions is of paramount importance.

[0003] Currently, mainstream reliability calculation methods can be divided into two categories: Monte Carlo algorithms and the method of moments. The Monte Carlo algorithm requires massive sampling of the statistical characteristics of structural random variables, followed by nonlinear response analysis, and then statistical analysis of the response results to obtain the final reliability analysis result. This process is quite cumbersome and computationally intensive, making it only suitable for simple structures and unsuitable for reliability assessment of transmission tower systems with many members. Furthermore, the method of moments is typically used in structural design; although it has higher computational efficiency, its accuracy still lags behind that of the Monte Carlo algorithm. Summary of the Invention

[0004] The purpose of this invention is to provide a method, apparatus, equipment, and storage medium for assessing the reliability of power transmission tower systems, which can efficiently and accurately assess the reliability of power transmission tower systems under multiple disasters.

[0005] To achieve the above objectives, embodiments of the present invention provide a reliability assessment method for transmission tower systems, comprising:

[0006] Probabilistic space partitioning is performed on the system structure parameters and disaster parameters of the transmission tower line to obtain representative point parameter samples;

[0007] Based on the representative point parameter samples, a first finite element analysis model is established, and a time-domain dynamic analysis is performed on the first finite element analysis model to obtain the dynamic response of the transmission tower system.

[0008] Based on the dynamic response, a probability density evolution equation is established;

[0009] Based on the probability density evolution equation, the failure probability of the transmission tower system under disaster is calculated, and the reliability of the transmission tower system is obtained based on the correlation between the failure probability and the reliability.

[0010] As an improvement to the above scheme, the step of performing time-domain dynamic analysis on the first finite element analysis model to obtain the dynamic response of the transmission tower system includes performing time-domain dynamic analysis after mass-converged simplification of the first finite element analysis model, specifically including:

[0011] The first finite element analysis model is divided into several node layers;

[0012] A unit force is applied to the node layer, and a compliance matrix is ​​constructed based on the node layer's response to the unit force.

[0013] Invert the flexibility matrix to obtain the stiffness matrix;

[0014] Based on the stiffness matrix, calculate the lumped mass of each node layer, and construct a mass matrix based on the lumped mass of each node layer;

[0015] Construct a damping matrix based on the mass matrix and the stiffness matrix;

[0016] The dynamic response of the transmission tower system is calculated based on the stiffness matrix, the mass matrix, and the damping matrix.

[0017] As an improvement to the above scheme, the probability density evolution equation is calculated using the following formula:

[0018]

[0019] Where, p XΘ (X, θ, t) represents the probability density of the dynamic response of the transmission tower system when the random variable Θ takes the value θ, where the random variable is a structural parameter or a disaster parameter; Let θ represent the first derivative of the structural response with respect to time when the random variable Θ takes the value θ; t represents time.

[0020] As an improvement to the above scheme, the disaster effect includes at least one disaster effect, and the method for calculating the failure probability specifically includes:

[0021] For each type of disaster, the probability density function of the dynamic response of the transmission tower system under different levels of disaster is solved according to the probability density evolution equation.

[0022] Based on the probability density function, calculate the expected response of the transmission tower system under different levels of disasters;

[0023] The expected response and disaster level of the transmission tower system are logarithmic and linear regression is performed to obtain the slope and intercept of the line.

[0024] Based on the slope of the straight line and the intercept, the failure probability of the transmission tower system under various disaster effects is calculated.

[0025] As an improvement to the above solution, the failure probability is calculated using the following formula:

[0026]

[0027] Among them, P f (IM) represents the failure probability; IM represents the disaster level; Φ represents the standard normal cumulative distribution function; a2 represents the intercept; a3 represents the slope of the line; X f This represents the response threshold corresponding to structural damage.

[0028] As an improvement to the above scheme, when there are two or more types of disasters, the failure probability under multiple disasters is calculated using the following formula:

[0029]

[0030] in, P[X>X] represents the failure probability under multiple disasters; m represents the type of disaster; X represents the dynamic response of the transmission tower system; P[X>X] represents the failure probability under multiple disasters. f [IM] indicates that the structural response exceeds X under a disaster of level IM. f The probability of; H represents the failure probability of the transmission tower system under the action of the i-th disaster; i (IM) represents the hazard function of the i-th type of disaster.

[0031] As an improvement to the above scheme, the dynamic response of the transmission tower system includes at least one of the following:

[0032] Displacement response at the junction of the main tower material and the crossbar, displacement response at the crossarm position, displacement response at the highest point of the tower top, displacement response at the mid-span of the conductor, acceleration response at the junction of the main tower material and the crossbar, acceleration response at the crossarm position, acceleration response at the highest point of the tower top, acceleration response at the mid-span of the conductor, stress in the main tower material, stress at the mid-span of the conductor, and stress at the mid-span of the ground wire.

[0033] To achieve the above objectives, embodiments of the present invention also provide a reliability assessment device for transmission tower systems, comprising:

[0034] The probability space partitioning module is used to perform probability space partitioning on the system parameters and disaster parameters of the transmission tower line structure to obtain representative point parameter samples.

[0035] The dynamic response acquisition module is used to establish a first finite element analysis model based on the representative point parameter samples, perform time-domain dynamic analysis on the first finite element analysis model, and obtain the dynamic response of the transmission tower line system.

[0036] The probability density evolution equation establishment module is used to establish the probability density evolution equation based on the dynamic response.

[0037] The reliability calculation module is used to calculate the failure probability of the transmission tower system under disaster based on the probability density evolution equation, and to obtain the reliability of the transmission tower system based on the correlation between the failure probability and reliability.

[0038] As an improvement to the above scheme, the dynamic response acquisition module further includes a mass concentration simplification unit. This mass concentration simplification unit is used to perform time-domain dynamic analysis on the first finite element analysis model after mass concentration simplification, specifically including:

[0039] The first finite element analysis model is divided into several node layers;

[0040] A unit force is applied to the node layer, and a compliance matrix is ​​constructed based on the node layer's response to the unit force.

[0041] Invert the flexibility matrix to obtain the stiffness matrix;

[0042] Based on the stiffness matrix, calculate the lumped mass of each node layer, and construct a mass matrix based on the lumped mass of each node layer;

[0043] Construct a damping matrix based on the mass matrix and the stiffness matrix;

[0044] The dynamic response of the transmission tower system is calculated based on the stiffness matrix, the mass matrix, and the damping matrix.

[0045] As an improvement to the above scheme, the probability density evolution equation establishment module is used to calculate the probability density evolution equation using the following formula:

[0046]

[0047] Where, p XΘ (X, θ, t) represents the probability density of the dynamic response of the transmission tower system when the random variable Θ takes the value θ, where the random variable is a structural parameter or a disaster parameter; Let θ represent the first derivative of the structural response with respect to time when the random variable Θ takes the value θ; t represents time.

[0048] As an improvement to the above scheme, the disaster effect includes at least one disaster effect, and the reliability calculation module is used for:

[0049] For each type of disaster, the probability density function of the dynamic response of the transmission tower system under different levels of disaster is solved according to the probability density evolution equation.

[0050] Based on the probability density function, calculate the expected response of the transmission tower system under different levels of disasters;

[0051] The expected response and disaster level of the transmission tower system are logarithmic and linear regression is performed to obtain the slope and intercept of the line.

[0052] Based on the slope of the straight line and the intercept, the failure probability of the transmission tower system under various disaster effects is calculated.

[0053] As an improvement to the above solution, the reliability calculation module is also used to calculate the failure probability using the following formula:

[0054]

[0055] Among them, P f (IM) represents the failure probability; Φ represents the standard normal cumulative distribution function; a2 represents the intercept; a3 represents the slope of the line; X f IM represents the response threshold corresponding to structural damage; IM represents the disaster level.

[0056] As an improvement to the above solution, when there are two or more types of disasters, the reliability calculation module is further used to calculate the failure probability under multiple disasters using the following formula:

[0057]

[0058] in, P[X>X] represents the failure probability under multiple disasters; m represents the type of disaster; X represents the dynamic response of the transmission tower system; P[X>X] represents the failure probability under multiple disasters. f [IM] indicates that the structural response exceeds X under a disaster of level IM. f The probability of; H represents the failure probability of the transmission tower system under the action of the i-th disaster; i (IM) represents the hazard function of the i-th type of disaster.

[0059] As an improvement to the above scheme, the dynamic response of the transmission tower system includes at least one of the following:

[0060] Displacement response at the junction of the main tower material and the crossbar, displacement response at the crossarm position, displacement response at the highest point of the tower top, displacement response at the mid-span of the conductor, acceleration response at the junction of the main tower material and the crossbar, acceleration response at the crossarm position, acceleration response at the highest point of the tower top, acceleration response at the mid-span of the conductor, stress in the main tower material, stress at the mid-span of the conductor, and stress at the mid-span of the ground wire.

[0061] To achieve the above objectives, embodiments of the present invention also provide a reliability assessment device for a transmission tower system, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the reliability assessment method for a transmission tower system as described in any of the above embodiments.

[0062] To achieve the above objectives, embodiments of the present invention also provide a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the transmission tower line system reliability assessment method as described in any of the above embodiments.

[0063] Compared with existing technologies, the reliability assessment method, apparatus, equipment, and storage medium for transmission tower and line systems provided in this invention perform probabilistic space partitioning of the transmission tower and line system structure parameters and disaster parameters to obtain representative point parameter samples; based on the representative point parameter samples, a first finite element analysis model is established, and time-domain dynamic analysis is performed on the first finite element analysis model to obtain the dynamic response of the transmission tower and line system; based on the dynamic response, a probability density evolution equation is established; based on the probability density evolution equation, the failure probability of the transmission tower and line system under disaster effects is calculated; and based on the correlation between the failure probability and reliability, the reliability of the transmission tower and line system is obtained, thereby enabling efficient and accurate assessment of the reliability of the transmission tower and line system under multiple disaster effects. Attached Figure Description

[0064] Figure 1 This is a flowchart of a reliability assessment method for a power transmission tower system provided in an embodiment of the present invention;

[0065] Figure 2 This is a schematic diagram of the transmission tower provided in Embodiment 1 of the present invention;

[0066] Figure 3 This is a schematic diagram of the probability space partitioning result provided in Embodiment 1 of the present invention;

[0067] Figure 4 This is a schematic diagram of the transmission tower structure model provided in Embodiment 1 of the present invention;

[0068] Figure 5 This is a schematic diagram of the displacement response of the top of the transmission tower under the El-Centro earthquake provided in Embodiment 1 of the present invention;

[0069] Figure 6 This is a comparison diagram between the simplified model provided in Embodiment 1 of the present invention and the original model;

[0070] Figure 7This is a schematic diagram illustrating the statistical results of the node's quality and height provided in Embodiment 1 of the present invention;

[0071] Figure 8 This is a schematic diagram of the force application position provided in Embodiment 1 of the present invention;

[0072] Figure 9 This is a schematic diagram of the structural response provided in Embodiment 1 of the present invention;

[0073] Figure 10 This is a comparison diagram of the displacement response of the original model and the simplified model provided in Embodiment 1 of the present invention;

[0074] Figure 11 This is a schematic diagram illustrating the change of probability density over time as provided in Embodiment 1 of the present invention;

[0075] Figure 12 This is another schematic diagram illustrating the change of probability density over time provided in Embodiment 1 of the present invention;

[0076] Figure 13 This is a schematic diagram of structural vulnerability curves under different intensities of load provided in Embodiment 1 of the present invention;

[0077] Figure 14 This is a schematic diagram of the hazard function of a transmission tower subjected to earthquakes of different intensities, provided in Embodiment 1 of the present invention.

[0078] Figure 15 This is a schematic diagram of the danger function of a transmission tower subjected to strong winds of different wind speeds, provided in Embodiment 1 of the present invention.

[0079] Figure 16 This is a schematic diagram of the structure of a reliability assessment device for a power transmission tower system provided in an embodiment of the present invention;

[0080] Figure 17 This is a schematic diagram of the structure of a reliability assessment device for a power transmission tower system provided in an embodiment of the present invention. Detailed Implementation

[0081] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some 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.

[0082] It is worth noting that in recent years, with the continuous improvement of power grid construction, deterministic dynamic analysis methods for transmission tower systems under single disaster effects have matured, and a series of finite element modeling and simulation calculation methods have been developed, basically achieving the solution of various nonlinear problems of structures (material nonlinearity, geometric nonlinearity, boundary condition nonlinearity, and special connection unit nonlinearity). However, due to the large number of structural members in transmission towers, nonlinear stochastic analysis is quite difficult, and its reliability analysis algorithm is still relatively basic. Currently, efficient reliability calculation at the transmission tower system level under multiple disaster effects has not yet been achieved. The transmission tower system reliability assessment method, device, equipment, and storage medium provided in this invention can not only solve the technical problems mentioned in the background art, but also be used to assess the reliability of transmission tower systems under multiple disaster effects.

[0083] See Figure 1 This is a flowchart of a reliability assessment method for a transmission tower system provided in an embodiment of the present invention, including steps S1 to S4:

[0084] S1. Perform probability space partitioning on the system parameters and disaster parameters of the transmission tower line structure to obtain representative point parameter samples;

[0085] S2. Based on the representative point parameter sample, establish a first finite element analysis model, perform time-domain dynamic analysis on the first finite element analysis model, and obtain the dynamic response of the transmission tower system.

[0086] S3. Based on the dynamic response, establish the probability density evolution equation;

[0087] S4. Calculate the failure probability of the transmission tower system under disaster based on the probability density evolution equation, and obtain the reliability of the transmission tower system based on the correlation between the failure probability and reliability.

[0088] It is worth noting that when analyzing the reliability of the transmission tower system under multiple disasters, it is necessary to comprehensively consider the randomness of structural parameters and the randomness of disasters. Therefore, in step S1, probability space is partitioned based on the statistical results of the transmission tower system structure parameters and the statistical results of the main disaster parameters (such as wind and earthquake). The partitioning results will generate several representative point parameter samples in the probability space, and each representative point parameter sample corresponds to one assigned probability.

[0089] For example, let s be an s-dimensional continuous random vector Θ = (Θ1, Θ2, ..., Θ3). s The range space of ) is set up For the distribution space Ω ΘThe probability space is divided into several subsets by the Voronoi set partitioning method, which uses the above n discrete points. Each discrete point represents a sample in the probability space and corresponds to an assigned probability.

[0090] In step S2, a first finite element analysis model is established based on the representative point parameter samples (structural parameter samples and load parameter samples) obtained from step S1. For example, the first finite element analysis model is a refined finite element analysis model. To facilitate large-scale calculations, this model employs parametric modeling methods and is established using a commercial finite element software API (Application Programming Interface).

[0091] Furthermore, considering the P-delta effect (second-order gravitational effect) and geometric nonlinearity of the transmission line, time-domain dynamic analysis is conducted to obtain the dynamic response (dynamic response time history results) of the transmission tower-line system. For example, parametric methods are used to extract the dynamic response time history results of key points of the transmission tower, conductors, and ground wire. For example, the dynamic response time history results of key points can be the displacement time history response at the following locations: the junction of the main tower material and the crossarm, the crossarm position, the highest point of the tower top, and the mid-span of the conductor; they can be the acceleration time history response at the following locations: the junction of the main tower material and the crossarm, the crossarm position, the highest point of the tower top, and the mid-span of the conductor; they can be the stress at the following locations: the main tower material, the mid-span of the conductor, and the mid-span of the ground wire. Compared with the existing technology that linearly simplifies the transmission tower-line system, this embodiment of the invention retains the nonlinear characteristics of the transmission tower-line system and further uses nonlinear random response analysis in step S3 to obtain the probability density of its random response, thereby more accurately describing the characteristics of the random response of the transmission tower-line system.

[0092] For example, in step S3, a probability density evolution equation is established, and the probability density evolution equation is solved using the TVD (Total Variation Diminishing) scheme to obtain the time-varying dynamic response of the transmission tower system corresponding to each assigned probability. The process of iterating and superimposing at each representative point yields the time-varying process of the overall nonlinear random response probability density of the transmission tower system.

[0093] It is worth noting that the dynamic response obtained in step S2 can be understood as a deterministic time-varying function, while step S3 maps the deterministic response obtained in step S2 to a probability space, obtaining the probability density function of the response. For example, step S2 can obtain the displacement of the transmission tower system at any time under the action of a specific seismic wave; after step S3, the probability of the displacement response of the transmission tower system at a certain time under a series of seismic actions can be obtained.

[0094] Furthermore, in step S4, the reliability of the transmission tower system is calculated based on the probability density information of the nonlinear random response of the transmission tower system, so as to guide the optimized design or reinforcement and renovation of the transmission tower structure.

[0095] Compared with the prior art, the reliability evaluation method of the transmission tower line system provided by the embodiments of the present invention calculates reliability based on probability density evolution theory, which can effectively balance the high accuracy and high efficiency of the reliability assessment of the transmission tower line system, and can be applied to the efficient reliability calculation of the transmission tower line system under multiple disasters.

[0096] As one optional implementation, the step of performing time-domain dynamic analysis on the first finite element analysis model to obtain the dynamic response of the transmission tower system includes performing time-domain dynamic analysis after mass-simplification of the first finite element analysis model, specifically including:

[0097] The first finite element analysis model is divided into several node layers;

[0098] A unit force is applied to the node layer, and a compliance matrix is ​​constructed based on the node layer's response to the unit force.

[0099] Invert the flexibility matrix to obtain the stiffness matrix;

[0100] Based on the stiffness matrix, calculate the lumped mass of each node layer, and construct a mass matrix based on the lumped mass of each node layer;

[0101] Construct a damping matrix based on the mass matrix and the stiffness matrix;

[0102] The dynamic response of the transmission tower system is calculated based on the stiffness matrix, the mass matrix, and the damping matrix.

[0103] To improve the computational efficiency of dynamic response, the first finite element analysis model needs to be simplified by mass lumping, that is, a simplified lumped mass model needs to be established, and then the response analysis is performed using this simplified lumped mass model. Specifically, the first finite element analysis model is divided into n node layers (also called "nodes") from bottom to top. For example, the locations of the crossarms and diaphragms are usually considered as one node layer.

[0104] Furthermore, a unit force is applied at the i-th node layer to obtain the structural response, which can be expressed as a vector to obtain the compliance vector:

[0105] δ1={δ 1，1 δ 2，1 , …, δ n，1} T (1)

[0106] Where, δi，1 δ1 represents the displacement of the i-th node when a unit force is applied to the 1-node layer; δ1 represents the compliance vector when a unit force is applied to the 1-node layer; T represents the transpose operation.

[0107] Furthermore, arranging the compliance vectors into matrix form yields the compliance matrix:

[0108] Δ=[δ1, δ2, …, δ n (2)

[0109] Where Δ represents the compliance matrix; δ n This represents the compliance vector when a unit force is applied to the nth node layer.

[0110] Furthermore, inverting the flexibility matrix yields the stiffness matrix [K], which is:

[0111] [K] = [Δ] -1 (3)

[0112] Furthermore, the mass matrix is ​​written as shown in equation (4):

[0113] [M] = diag(m1, m2, ... m) n (4)

[0114] Where [M] represents the mass matrix; diag() represents constructing the angle matrix; m i Let represent the concentrated mass of the i-th node layer, and solve it using formula (5):

[0115]

[0116] Where, ω i k represents the i-th order angular frequency; i，1 k i，2 , ..., k i，n For the corresponding element in the stiffness matrix; [φ 1，i φ 2，i , …, φ n，i ] T This represents the shape of the i-th mode.

[0117] Furthermore, based on the Rayleigh damping assumption, the damping matrix is ​​derived [C]:

[0118] [C] = a0[M] + a1[K] (6)

[0119] Where a0 and a1 are two proportionality coefficients, and:

[0120]

[0121] For the transmission tower structure, the damping ratio ξ is taken as 2%, that is, ξ = 0.02.

[0122] Furthermore, based on the stiffness matrix, mass matrix, and damping matrix, the dynamic response of the transmission tower system is calculated, as shown in formula (8):

[0123]

[0124] in, This represents the acceleration response of the transmission tower system; {x} represents the velocity response of the transmission tower system; {p} represents the displacement response of the transmission tower system; and {p} represents the force vector acting on each node.

[0125] As one optional implementation, the probability density evolution equation is calculated using the following formula:

[0126]

[0127] Where, p XΘ (X, θ, t) represents the probability density of the dynamic response of the transmission tower system when the random variable Θ takes the value θ, where the random variable is a structural parameter or a disaster parameter; Let θ represent the first derivative of the structural response with respect to time when the random variable Θ takes the value θ; t represents time; where structural response refers to the dynamic response of the transmission tower system.

[0128] For example, the dynamic response of the transmission tower system (such as the displacement response at the junction of the main tower material and the crossarm, the displacement response at the crossarm position, the displacement response at the highest point of the tower top, the displacement response in the conductor span, the stress in the main tower material, the stress in the conductor span, and the stress in the ground wire span, etc.) is denoted as:

[0129] X(t)=(X1,X2,X3,…,X m ) T (10)

[0130] Where X1, X2, X3, ..., X m These represent the responses at points 1, 2, 3...m of the structure, respectively.

[0131] Then X(t) is a function of the random variable Θ, that is:

[0132] X(t)=H(Θ,t)(11)

[0133] Furthermore, the derivative of X(t) with respect to the generalized time parameter t can be expressed as:

[0134]

[0135] The probability density evolution equation of the transmission tower system can be expressed as:

[0136]

[0137] Where, p XΘ (X, θ, t) represents the probability density of the dynamic response of the transmission tower system when the random variable Θ takes the value θ. It is a function of time t, and the random variable is a structural parameter or a disaster parameter. Let θ represent the first derivative of the structural response with respect to time when the random variable Θ takes the value θ; t represents time.

[0138] When X(t) has a definite initial value x0 independent of the random vector Θ, the initial conditions of the probability density evolution equation can be expressed as:

[0139] p XΘ (X, θ, t)| t＝0 =δ(x-x0)P Θ (θ) (13)

[0140] Where δ() represents the Dirac function; P Θ (θ) represents the joint probability density function of Θ.

[0141] Furthermore, by solving the above probability density evolution equation, we can obtain the probability density function of X(t):

[0142]

[0143] For example, the probability density evolution equation is solved using the TVD scheme. First, the solution plane of xt is discretized, letting j = 0, ±1, ±2, ..., and k = 0, 1, 2, ... . At this point, This indicates that p(x, t) is at the point (x, t). j , t k The value at position ) is p(x) j , t k ), where x j =j·Δx,t k = k·Δt, where Δx represents the spatial dispersion step and Δt represents the time dispersion step.

[0144] According to the TVD difference scheme, we can obtain:

[0145]

[0146] Where λ=Δt / Δx represents the grid ratio; a represents the derivative of the physical quantity being sought; This represents the flux limiter. To ensure the stability and convergence of the TVD scheme, the CFL condition (Courant-Friedrichs-Lewy condition) must be satisfied, i.e., |λa|≤1.

[0147] As one optional implementation, the disaster effect includes at least one disaster effect, and the method for calculating the failure probability specifically includes:

[0148] For each type of disaster, the probability density function of the dynamic response of the transmission tower system under different levels of disaster is solved according to the probability density evolution equation.

[0149] Based on the probability density function, the expected response of the transmission tower system under different levels of disasters is calculated;

[0150] The logarithm of the expected response and disaster level of the transmission tower system is taken, and linear regression is performed to obtain the slope and intercept of the line.

[0151] Based on the slope of the straight line and the intercept, the failure probability of the transmission tower system under various disaster effects is calculated.

[0152] For example, firstly, disasters can be divided into several levels, and let IM represent the disaster level. For instance, earthquake action can be divided into levels such as IM = 0.05g (gravitational acceleration), 0.1g to 0.8g; wind load can be divided into levels such as IM = 10m / s, 15m / s to 40m / s. For the i-th level disaster, the probability density function p of the dynamic response of the transmission tower system is solved according to formulas (9) and (14). X Furthermore, the expected response E(X)|IM of the transmission tower system under a disaster of level IM is:

[0153] E(X)|IM=∫X·p x |IMdx (16)

[0154] Furthermore, by taking n different values ​​for IM, the expected response of the transmission tower system under different levels of disaster can be obtained according to formula (16): E(X)|IM1, E(X)|IM2, ..., E(X)|IM n For E(X)|IM i and disaster level IM i Taking the logarithm of each, we get ln(E(X)|IM) i ) and ln(IM i Furthermore, for ln(E(X)|IM) i ) and ln(IM i Perform linear regression to obtain the slope a3 and intercept a2 of the line. Define the response threshold corresponding to structural damage as X. f The failure probability of the transmission tower system under this type of disaster is expressed as:

[0155]

[0156] Among them, P f (IM) represents the failure probability; Φ represents the standard normal cumulative distribution function; a2 represents the intercept; a3 represents the slope of the line; X f IM represents the response threshold corresponding to structural damage; IM represents the disaster level.

[0157] By repeating the above process for z different disasters, the failure probability under the action of z disasters can be obtained.

[0158] Let H i (IM) represents the hazard function for the i-th type of disaster, from which the failure probability of the transmission tower system under various types of disasters can be obtained:

[0159]

[0160] in, P[X>X] represents the failure probability under multiple disasters; m represents the type of disaster; X represents the dynamic response of the transmission tower system; P[X>X] represents the failure probability under multiple disasters. f The table shows the structural response exceeding X under a disaster of level IM. f The probability of; H represents the failure probability of the transmission tower system under the action of the i-th disaster; i (IM) represents the hazard function of the i-th type of disaster.

[0161] Furthermore, considering the correlation between failure probability and reliability, the reliability index can be obtained:

[0162]

[0163] Where β(t) represents the reliability index; Φ represents the standard normal cumulative distribution function, Φ -1 This represents the corresponding inverse function.

[0164] As one optional implementation, the dynamic response of the transmission tower system includes at least one of the following:

[0165] Displacement response at the junction of the main tower material and the crossbar, displacement response at the crossarm position, displacement response at the highest point of the tower top, displacement response at the mid-span of the conductor, acceleration response at the junction of the main tower material and the crossbar, acceleration response at the crossarm position, acceleration response at the highest point of the tower top, acceleration response at the mid-span of the conductor, stress in the main tower material, stress at the mid-span of the conductor, and stress at the mid-span of the ground wire.

[0166] To better understand the reliability assessment method for transmission tower systems, the following explanation will use the reliability calculation of a transmission tower system under earthquake and wind conditions as an example.

[0167] Assume a power transmission tower is designed to have a service life of 50 years, and its three-dimensional shape is as shown.

[0168] The first step is to perform probability space partitioning. The transmission tower system contains multiple types of random variables, such as material resistance, cross-sectional dimensions, and external loads. To simplify calculations, only permanent loads, member resistance, seismic action, and wind loads are selected as random variables. Referring to the *Code for Design of Steel Structures* (GB50017-2020) and the *Technical Specification for Design of Overhead Transmission Line Tower Structures* (DL / T 5154-2012), the permanent loads are assumed to follow a normal distribution with a coefficient of variation of 0.07. Member resistances are calculated as axially loaded members, following a log-normal distribution with a coefficient of variation of 0.07. According to the *Code for Seismic Design of Power Facilities* (GB 50260-2013), the seismic intensity of this transmission tower system is set at 7 degrees, with return periods of 50 years, 475 years, and 2475 years for frequent, occasional, and rare earthquakes, respectively. Wind-induced vibration is defined using the average wind speed at a height of 10 meters as the indicator for wind load levels. The Voronoi set partitioning method was used for point selection and probability space partitioning, and the results are as follows: Figure 3 As shown.

[0169] The second step involves calculating the dynamic response of the transmission tower-line system based on a refined finite element model. Multiple finite element models and calculations are performed using the representative point parameter samples extracted in the first step. (See [link to relevant documentation]). Figure 4 This is a transmission tower structure model calculated and established using the Python language and the API interface program included with SAP2000, as described in this embodiment of the invention. See also... Figure 5 , is the time history function of the displacement response at the top of the transmission tower under the action of the El-Centro earthquake. The calculation process of the dynamic response of other key points of the transmission tower system is similar and will not be described in detail here.

[0170] The third step involves calculating the dynamic response of the transmission tower system based on a simplified model. The refined finite element model from the second step is simplified using the method described in the above embodiment. Nodes are divided according to the positions of crossarms and diaphragms, resulting in 21 nodes from bottom to top for the transmission tower structure model. (See [link to previous step]). Figure 6 This is a comparison diagram between the simplified model and the original model. Unit forces are applied sequentially to the node layers to obtain the response of the simplified model, which in turn yields the flexibility matrix of the structure. The mass matrix is ​​then obtained using formulas (4) and (5). (See [reference]). Figure 7 These are the statistical results of the mass and height of each node in the embodiments of the present invention. To make the displacement response of the structure more obvious, the unit force is amplified by a certain factor before being applied. An example of the force application location is shown below. Figure 8 As shown, the response of the structure is as follows Figure 9As shown. Furthermore, to verify the accuracy of the results calculated based on the simplified model, the displacement responses of the original model and the simplified model were compared after applying the same seismic force. The comparison results are shown below. Figure 10 As shown, by Figure 10 It can be seen that the displacement responses output by the two models are basically the same, meaning that the calculation results of the simplified model still have high accuracy.

[0171] The fourth step is to establish and solve the probability density evolution equation. Based on the dynamic response calculation of the transmission tower system calculated in the second and / or third steps, the probability density evolution equation is established according to formula (9), and the probability density change process over time is calculated according to formula (15), such as... Figure 11 and Figure 12 As shown.

[0172] Step 5: Reliability Assessment. The vulnerability curves of the structure under different load intensities can be obtained from the probability density evolution results, as shown below. Figure 13 As shown. Referring to the structural seismic and wind resistance codes, the hazard functions for transmission towers subjected to earthquakes of different intensities or winds of different speeds during their service life can be obtained as follows: Figure 14 and Figure 15 As shown. According to formula (18), the failure probability of this transmission tower system within a 50-year service life is 1.999 × 10. -4 According to formula (19), the reliability of the structure under the two types of disasters of earthquake and wind load during the whole life cycle is 3.54.

[0173] Compared with existing technologies, the reliability assessment method for transmission tower and line systems provided in this invention performs probability space partitioning of the system structure parameters and disaster parameters of the transmission tower and line system to obtain representative point parameter samples; based on the representative point parameter samples, a first finite element analysis model is established, and time-domain dynamic analysis is performed on the first finite element analysis model to obtain the dynamic response of the transmission tower and line system; based on the dynamic response, a probability density evolution equation is established; based on the probability density evolution equation, the failure probability of the transmission tower and line system under disaster effects is calculated; and based on the correlation between the failure probability and reliability, the reliability of the transmission tower and line system is obtained, thereby enabling efficient and accurate assessment of the reliability of the transmission tower and line system under multiple disaster effects.

[0174] See Figure 16 This invention also provides a reliability assessment device 10 for a power transmission tower system, comprising:

[0175] The probability space partitioning module 11 is used to perform probability space partitioning on the transmission tower system structure parameters and disaster parameters to obtain representative point parameter samples.

[0176] The dynamic response acquisition module 12 is used to establish a first finite element analysis model based on the representative point parameter sample, perform time-domain dynamic analysis on the first finite element analysis model, and obtain the dynamic response of the transmission tower line system.

[0177] The probability density evolution equation establishment module 13 is used to establish the probability density evolution equation based on the dynamic response.

[0178] The reliability calculation module 14 is used to calculate the failure probability of the transmission tower line system under disaster action according to the probability density evolution equation, and to obtain the reliability of the transmission tower line system according to the correlation between the failure probability and the reliability.

[0179] As one optional implementation, the dynamic response acquisition module 12 further includes a mass concentration simplification unit, which is used to perform time-domain dynamic analysis on the first finite element analysis model after mass concentration simplification, specifically including:

[0180] The first finite element analysis model is divided into several node layers;

[0181] A unit force is applied to the node layer, and a compliance matrix is ​​constructed based on the node layer's response to the unit force.

[0182] Invert the flexibility matrix to obtain the stiffness matrix;

[0183] Based on the stiffness matrix, calculate the lumped mass of each node layer, and construct a mass matrix based on the lumped mass of each node layer;

[0184] Construct a damping matrix based on the mass matrix and the stiffness matrix;

[0185] The dynamic response of the transmission tower system is calculated based on the stiffness matrix, the mass matrix, and the damping matrix.

[0186] As one optional implementation, the probability density evolution equation establishment module 13 is used to calculate the probability density evolution equation using the following formula:

[0187]

[0188] Where, p XΘ (X, θ, t) represents the probability density of the dynamic response of the transmission tower system when the random variable Θ takes the value θ, where the random variable is a structural parameter or a disaster parameter; Let θ represent the first derivative of the structural response with respect to time when the random variable Θ takes the value θ; t represents time.

[0189] As one optional implementation, the disaster effect includes at least one disaster effect, and the reliability calculation module 14 is used for:

[0190] For each type of disaster, the probability density function of the dynamic response of the transmission tower system under different levels of disaster is solved according to the probability density evolution equation.

[0191] Based on the probability density function, calculate the expected response of the transmission tower system under different levels of disasters;

[0192] The expected response and disaster level of the transmission tower system are logarithmic and linear regression is performed to obtain the slope and intercept of the line.

[0193] Based on the slope of the straight line and the intercept, the failure probability of the transmission tower system under various disaster effects is calculated.

[0194] As one optional implementation, the reliability calculation module 14 is further configured to calculate the failure probability using the following formula:

[0195]

[0196] Among them, P f (IM) represents the failure probability; Φ represents the standard normal cumulative distribution function; a2 represents the intercept; a3 represents the slope of the line; X f IM represents the response threshold corresponding to structural damage; IM represents the disaster level.

[0197] As one optional implementation, when there are two or more types of disasters, the reliability calculation module 14 is further used to calculate the failure probability under multiple disasters using the following formula:

[0198]

[0199] in, P[X>X] represents the failure probability under multiple disasters; m represents the type of disaster; X represents the dynamic response of the transmission tower system; P[X>X] represents the failure probability under multiple disasters. f [IM] indicates that the structural response exceeds X under a disaster of level IM. f The probability of; H represents the failure probability of the transmission tower system under the action of the i-th disaster; i (IM) represents the hazard function of the i-th type of disaster.

[0200] As one optional implementation, the dynamic response of the transmission tower system includes at least one of the following:

[0201] Displacement response at the junction of the main tower material and the crossbar, displacement response at the crossarm position, displacement response at the highest point of the tower top, displacement response at the mid-span of the conductor, acceleration response at the junction of the main tower material and the crossbar, acceleration response at the crossarm position, acceleration response at the highest point of the tower top, acceleration response at the mid-span of the conductor, stress in the main tower material, stress at the mid-span of the conductor, and stress at the mid-span of the ground wire.

[0202] The reliability assessment device for transmission tower and line systems provided in this embodiment of the invention can realize all the process steps of the reliability assessment method for transmission tower and line systems described in the above embodiments. The functions and technical effects of each module and unit in the device are the same as the functions and technical effects of the reliability assessment method for transmission tower and line systems described in the above embodiments. The specific implementation method will not be described in detail here.

[0203] See Figure 17 This invention also provides a transmission tower system reliability assessment device 20, including a processor 21, a memory 22, and a computer program stored in the memory 22 and configured to be executed by the processor 21. When the processor 21 executes the computer program, it implements the steps described in the above-described transmission tower system reliability assessment method embodiment, for example... Figure 1 The steps S1 to S4 described above; or, when the processor 21 executes the computer program, it implements the functions of each module in the above-described device embodiments.

[0204] The transmission tower system reliability assessment device 20 can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The transmission tower system reliability assessment device 20 may include, but is not limited to, a processor 21 and a memory 22. Those skilled in the art will understand that the schematic diagram is merely an example of the transmission tower system reliability assessment device 20 and does not constitute a limitation on the device. It may include more or fewer components than shown in the diagram, or combine certain components, or use different components. For example, the transmission tower system reliability assessment device 20 may also include input / output devices, network access devices, buses, etc.

[0205] The processor 21 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 21 can be any conventional processor. The processor 21 is the control center of the transmission tower system reliability assessment device 20, connecting all parts of the device through various interfaces and lines.

[0206] The memory 22 can be used to store the computer programs and / or modules. The processor 21 implements various functions of the transmission tower system reliability assessment device 20 by running or executing the computer programs and / or modules stored in the memory 22 and calling the data stored in the memory 22. The memory 22 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function, etc.; the data storage area may store data created according to the use of the controller, etc. In addition, the memory 22 may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0207] The integrated modules of the transmission tower system reliability assessment device 20, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0208] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A reliability assessment method for a power transmission tower system, characterized in that, include: Probabilistic space partitioning is performed on the system structure parameters and disaster parameters of the transmission tower line to obtain representative point parameter samples; Based on the representative point parameter samples, a first finite element analysis model is established, and a time-domain dynamic analysis is performed on the first finite element analysis model to obtain the dynamic response of the transmission tower system. Based on the dynamic response, a probability density evolution equation is established; Based on the probability density evolution equation, the failure probability of the transmission tower system under disaster is calculated, and the reliability of the transmission tower system is obtained based on the correlation between the failure probability and the reliability. The disaster effect includes at least one disaster effect, and the method for calculating the failure probability specifically includes: For each type of disaster, the probability density function of the dynamic response of the transmission tower system under different levels of disaster is solved according to the probability density evolution equation. Based on the probability density function, calculate the expected response of the transmission tower system under different levels of disasters; The expected response and disaster level of the transmission tower system are logarithmic and linear regression is performed to obtain the slope and intercept of the line. Based on the slope of the straight line and the intercept, the failure probability of the transmission tower system under various disaster effects is calculated.

2. The reliability assessment method for transmission tower and line systems as described in claim 1, characterized in that, The step of performing time-domain dynamic analysis on the first finite element analysis model to obtain the dynamic response of the transmission tower system includes performing time-domain dynamic analysis after mass-converged simplification of the first finite element analysis model, specifically including: The first finite element analysis model is divided into several node layers; A unit force is applied to the node layer, and a compliance matrix is ​​constructed based on the node layer's response to the unit force. Invert the flexibility matrix to obtain the stiffness matrix; Based on the stiffness matrix, calculate the lumped mass of each node layer, and construct a mass matrix based on the lumped mass of each node layer; Construct a damping matrix based on the mass matrix and the stiffness matrix; The dynamic response of the transmission tower system is calculated based on the stiffness matrix, the mass matrix, and the damping matrix.

3. The reliability assessment method for transmission tower and line systems as described in claim 1, characterized in that, The probability density evolution equation is calculated using the following formula: in, Represents random variables Values At that time, the probability density of the dynamic response of the transmission tower system is given by random variables, which are structural parameters or disaster parameters. Represents random variables Values The first derivative of the time-structured response; Indicates time.

4. The reliability assessment method for transmission tower and line systems as described in claim 1, characterized in that, The failure probability is calculated using the following formula: in, Indicates the probability of failure; Represents the standard normal cumulative distribution function; Indicates the intercept; Indicates the slope of a straight line; This represents the response threshold corresponding to structural damage. Indicates the level of disaster.

5. The reliability assessment method for transmission tower and line systems as described in claim 1, characterized in that, When there are two or more types of disasters, the failure probability under multiple disaster effects is calculated using the following formula: in, Indicates the failure probability under the influence of multiple disasters; Indicates the type of disaster; This indicates the dynamic response of the transmission tower and line system; Indicates the level as IM Structural response exceeding the limits under disaster effects The probability of; Indicates the first The failure probability of a power transmission tower system under various disasters; Indicates the first The risk function of a type of disaster.

6. The reliability assessment method for transmission tower and line systems as described in claim 1, characterized in that, The dynamic response of the transmission tower system includes at least one of the following: Displacement response at the junction of the main tower material and the crossbar, displacement response at the crossarm position, displacement response at the highest point of the tower top, displacement response at the mid-span of the conductor, acceleration response at the junction of the main tower material and the crossbar, acceleration response at the crossarm position, acceleration response at the highest point of the tower top, acceleration response at the mid-span of the conductor, stress in the main tower material, stress at the mid-span of the conductor, and stress at the mid-span of the ground wire.

7. A reliability assessment device for a power transmission tower system, characterized in that, include: The probability space partitioning module is used to perform probability space partitioning on the system parameters and disaster parameters of the transmission tower line structure to obtain representative point parameter samples. The dynamic response acquisition module is used to establish a first finite element analysis model based on the representative point parameter samples, perform time-domain dynamic analysis on the first finite element analysis model, and obtain the dynamic response of the transmission tower line system. The probability density evolution equation establishment module is used to establish the probability density evolution equation based on the dynamic response. The reliability calculation module is used to calculate the failure probability of the transmission tower line system under disaster based on the probability density evolution equation, and to obtain the reliability of the transmission tower line system based on the correlation between the failure probability and the reliability. The disaster effect includes at least one disaster effect, and the reliability calculation module is used for: For each type of disaster, the probability density function of the dynamic response of the transmission tower system under different levels of disaster is solved according to the probability density evolution equation. Based on the probability density function, calculate the expected response of the transmission tower system under different levels of disasters; The expected response and disaster level of the transmission tower system are logarithmic and linear regression is performed to obtain the slope and intercept of the line. Based on the slope of the straight line and the intercept, the failure probability of the transmission tower system under various disaster effects is calculated.

8. The reliability assessment device for transmission tower and line systems as described in claim 7, characterized in that, The dynamic response acquisition module further includes a mass simplification unit, which is used to perform time-domain dynamic analysis on the first finite element analysis model after mass simplification. Specifically, it includes: The first finite element analysis model is divided into several node layers; A unit force is applied to the node layer, and a compliance matrix is ​​constructed based on the node layer's response to the unit force. Invert the flexibility matrix to obtain the stiffness matrix; Based on the stiffness matrix, calculate the lumped mass of each node layer, and construct a mass matrix based on the lumped mass of each node layer; Construct a damping matrix based on the mass matrix and the stiffness matrix; The dynamic response of the transmission tower system is calculated based on the stiffness matrix, the mass matrix, and the damping matrix.

9. The reliability assessment device for transmission tower and line systems as described in claim 7, characterized in that, The probability density evolution equation establishment module is used to calculate the probability density evolution equation using the following formula: in, Represents random variables Values At that time, the probability density of the dynamic response of the transmission tower system is given by random variables, which are structural parameters or disaster parameters. Represents random variables Values The first derivative of the time-structured response; Indicates time.

10. The reliability assessment device for transmission tower and line systems as described in claim 7, characterized in that, The reliability calculation module is also used to calculate the failure probability using the following formula: in, Indicates the probability of failure; Represents the standard normal cumulative distribution function; Indicates the intercept; Indicates the slope of a straight line; This represents the response threshold corresponding to structural damage. Indicates the level of disaster.

11. The reliability assessment device for transmission tower and line systems as described in claim 7, characterized in that, When there are two or more types of disasters, the reliability calculation module is also used to calculate the failure probability under multiple disasters using the following formula: in, Indicates the failure probability under the influence of multiple disasters; Indicates the type of disaster; This indicates the dynamic response of the transmission tower and line system; Indicates the level as IM Structural response exceeding the limits under disaster effects The probability of; Indicates the first The failure probability of a power transmission tower system under various disasters; Indicates the first The risk function of a type of disaster.

12. The reliability assessment device for transmission tower and line systems as described in claim 7, characterized in that, The dynamic response of the transmission tower system includes at least one of the following: Displacement response at the junction of the main tower material and the crossbar, displacement response at the crossarm position, displacement response at the highest point of the tower top, displacement response at the mid-span of the conductor, acceleration response at the junction of the main tower material and the crossbar, acceleration response at the crossarm position, acceleration response at the highest point of the tower top, acceleration response at the mid-span of the conductor, stress in the main tower material, stress at the mid-span of the conductor, and stress at the mid-span of the ground wire.

13. A reliability assessment device for a power transmission tower system, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to implement the reliability assessment method for transmission tower line systems as described in any one of claims 1 to 6.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform the reliability assessment method for transmission tower line systems as described in any one of claims 1 to 6.

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