CN111985018A - Calculation method for designing wind load of ultrahigh large-span tower and line based on inertia force method and tower line separation method and considering tower line coupling influence - Google Patents

Abstract

The invention discloses a calculation method for ultra-high and large-span towers and line wind loads based on an inertial force method and a tower-line separation method considering the influence of tower-line coupling. Based on the influence factor of the tower-line coupling, the equivalent damping coefficient of the tower, the wind vibration coefficient of the super-large spanning tower of the tower-line system, the wind-vibration coefficient of the maximum wind deflection angle of the suspended insulator string of the tower-line system, and the wind vibration coefficient of the tower-line system are obtained. Load pulsation reduction coefficient; modify and calculate the wind vibration coefficient of the super-large spanning tower of the tower-line system and the wind-vibration coefficient of the wind deflection angle, and obtain the corrected wind-vibration coefficient of the super-large spanning tower of the tower-line system and the transmission line of the tower-line system. Modified wind vibration coefficient; based on the tower-line separation method, the design wind load of the ultra-high transmission tower and the design wind load of the long-span transmission line in the ultra-high and large-span tower-line system are calculated under the action of the equivalent vibration inertial force. Beneficial effects: the single tower is designed with high precision and reliability.

Description

Ultra-high and large spanning considering the influence of tower-line coupling based on inertial force method and tower-line separation method Calculation method of tower and line design wind load

technical field

The invention relates to the technical field, in particular to a calculation method for ultra-high spanning tower and line wind loads based on an inertial force method and a tower-line separation method considering the influence of tower-line coupling.

Background technique

A super-tall transmission tower is a transmission tower whose tower height exceeds the gradient wind height compared with conventional transmission towers.

Dynamic time history analysis can obtain the wind vibration response of the structure, but the wind vibration coefficient calculated by the tower design code is concise, convenient and time-saving, and this method is still widely used by designers at this stage. The wind vibration coefficient calculated by the specification should have the effect of making the wind vibration response of the transmission tower equivalent to the actual maximum wind vibration response. The use of accurate wind vibration coefficients for tower design is the premise to ensure the normal operation of transmission lines.

The wind load calculated by the tower design code is concise, convenient and time-saving, and this method is still widely used by designers at this stage. The wind load calculated by the code should have the effect of making the wind vibration response of the transmission tower equivalent to the actual maximum wind vibration response. Using accurate effective static wind load for tower design is the premise to ensure the normal operation of transmission lines. Among the existing power-related standards: such as literature (1) GB 50545-2010. Design specifications for 110kV ~ 750kV overhead transmission lines [S]. Beijing: China Planning Press, 2010; (2) GB 50665-2011. Design specifications for 1000kV overhead transmission lines [S]. Beijing: China Planning Press, 2011; (3) DL/T 5154-2012. Technical Regulations for the Design of Tower Structures for Overhead Transmission Lines [S]. Beijing: China Planning Press, 2012 and (4) DL/T 5504-2015. Technical regulations for large span design of UHV overhead transmission lines [S]. Beijing: China Planning Press, 2015, the value of the wind vibration coefficient of a single tower below 60m is given, and it is recommended to use the load when it is above 60m Standardized calculation of wind vibration coefficient. The wind vibration coefficient of the load specification is suitable for compact buildings with regular changes in shape and mass. The transmission tower is a lattice structure, and the mass and wind-blocking area of the cross-arm and the diaphragm have a great influence on the wind-vibration coefficient. In addition, the use of CFST is not considered in the calculation of wind vibration coefficients in the load code. When using the random vibration theory to calculate the equivalent static wind load of a transmission tower, the expression involves complex multiple integrals, and the shape and mass distribution of the transmission tower are irregular, so it is difficult to summarize it with a unified expression. In addition, the aerodynamic damping of the wire increases with the increase of the average wind speed, and the resonance component of the wind vibration response is greatly reduced due to the aerodynamic damping, which can be ignored in the calculation. In addition, the single-tower system composed of ultra-high-span towers also needs to consider the correction caused by the coupling effect of the tower-line, which is of great significance for the final calculation of the high-precision wind load of the single-tower system.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides a calculation method for ultra-high spanning tower and line wind loads based on the inertial force method and the tower-line separation method considering the influence of the tower-line coupling, so as to improve the calculation accuracy of the wind load of the tower-line system. In order to achieve the above object, the concrete technical scheme adopted in the present invention is as follows:

超高大跨越塔的总高度H、跟开b₁、横担个数n_c、横担平均外伸长度

以及输电塔与导线、绝缘子串的布置方案；还包括导线线性和导线线长等。S2：基于塔线耦合影响因子，根据塔线体系中杆塔等效阻尼系数δ_e；S3：将步骤S2得到的塔线体系中杆塔等效阻尼系数δ_e来替换阻尼系数ζ₁，求取塔线体系超高大跨越塔的风振系数β(z)；考虑线形与线长影响因子，计算塔线体系悬垂绝缘子串最大风偏角的风振系数β；S4：考虑塔线耦合效应，求取塔线体系风荷载脉动折减系数ε_c；S5：根据步骤S4得到的塔线体系风荷载脉动折减系数，对步骤S3中的塔线体系超高大跨越塔的风振系数、塔线体系输电线的风振系数进行修正计算，得到塔线体系超高大跨越塔的修正风振系数β^*(z)和塔线体系输电线的修正风振系数β^*；S6：基于塔线分离法，在等效振动惯性力作用下计算超高大跨越塔线体系中超高输电塔的设计风荷载f_ESWL(z)和大跨越输电线的设计风荷载W_X。A calculation method for super-large spanning towers and line wind loads based on inertial force method and tower-line separation method considering the influence of tower line coupling. The physical parameters of super-large spanning towers, transmission lines, and insulator strings; the above data at least include the ground roughness category where the super-large spanning towers are located, and the average speed at a set height of 10m.

Total height H of super-large spanning tower, following opening b ₁ , number of cross-arm n _c , average outreach length of cross-arm

As well as the layout of transmission towers, wires, and insulator strings; it also includes wire linearity and wire length. S2: Based on the influence factor of the tower-line coupling, according to the equivalent damping coefficient δ _e of the tower in the tower-line system; S3: Replace the damping coefficient ζ ₁ with the equivalent damping coefficient δ _e of the tower in the tower-line system obtained in step S2, and obtain the tower Wind vibration coefficient β(z) of the super-high spanning tower of the line system; considering the influence factors of line shape and line length, calculate the wind vibration coefficient β of the maximum wind deflection angle of the pendant insulator string of the tower-line system; S4: considering the coupling effect of the tower line, obtain The wind load fluctuation reduction coefficient _εc of the tower-line system; S5: the wind-load fluctuation reduction coefficient of the tower-line system obtained according to step S4, the wind-vibration coefficient of the tower-line system in step S3, the wind vibration coefficient of the super-large spanning tower, and the power transmission of the tower-line system According to the correction calculation of the wind vibration coefficient of the line, the corrected wind vibration coefficient β ^* (z) of the tower-line system and the transmission line of the tower-line system are obtained; S6 ^: Based on the tower-line separation method, in Calculate the design wind load f _ESWL (z) of the ultra-high transmission tower and the design wind load W _X of the long-span transmission line in the super-high-span tower-line system under the action of equivalent vibration inertial force.

In a further technical solution, the specific steps of step S2 are:

S21: According to the tower line system of the super-large spanning tower in step S1, a calculation model diagram of the super-large spanning tower line system is obtained; The upper dimension becomes smaller, and the cross-arm is of equal cross-section; in the calculation model of the tower-line system, both ends of the wire are of equal height and are connected to the fixed hinge support; the height of the tower in the calculation model of the tower-line system is H, and the cross-arm cantilever The length is l _ca , the insulator length is l _in , and the wire span is L. There is no height difference between the wire hanging points. S22: Set the assumptions of the vibration of the transmission line and the insulator string, and obtain the mode shape diagram of the transmission line and the insulator string in the super-large spanning tower line system, as well as the generalized mass and generalized stiffness of the windward side and the windward side of the transmission line and the insulator string. and generalized damping; combine the transmission lines and insulator strings in the super-large spanning tower line system to form a cable structure system; the assumptions of the vibration of the conductors and insulator strings are: the vibration synchronization of the conductors on the windward side and the leeward side under wind load ; The frequency and damping ratio of the insulator string are controlled by the wire and are consistent with those of the wire. The generalized mass calculation formula of the windward side and the windward side conductor is:

所述迎风面、被风面导线的广义阻尼计算公式为：

m_c为单根导线单位线长的质量；单根导线振型

-L≤y≤L；γ_g为导线的自重比载；σ₀为导线的水平初应力；Γ为导线的线长，

ζ_c＝ζ_sc+ζ_ac；ζ_sc为导线结构阻尼比；ζ_ac为导线启动阻尼比；N_c为分裂导线的个数；T_w为平均风状态下单根导线的水平张力；ζ_c为导线阻尼比；所述迎风面、被风面绝缘子串的广义质量计算公式为：

所述迎风面、被风面绝缘子串的广义刚度计算公式为：

所述迎风面、被风面绝缘子串的广义阻尼计算公式为：

其中，m_in为绝缘子串单位高度质量；D_in为绝缘子串迎风外径；绝缘子串振型

H-l_in≤z≤H；ζ_in为绝缘子串阻尼比；

l_in为绝缘子长度；其中，索结构体系对应的广义质量、广义刚度和广义阻尼的计算公式为：

本发明中，下标ci表示索结构。The generalized stiffness calculation formula of the windward side and the windward side wire is:

The generalized damping calculation formula of the windward side and the windward side wire is:

m _c is the mass of a single wire per unit line length; the mode shape of a single wire

-L≤y≤L; γ _g is the self-weight specific load of the wire; σ ₀ is the horizontal initial stress of the wire; Γ is the wire length of the wire,

ζ _c = ζ _sc + ζ _ac ; ζ _sc is the damping ratio of the wire structure; ζ _ac is the start-up damping ratio of the wire; N _c is the number of split wires; _Tw is the horizontal tension of a single wire under the average wind condition; ζ _c is the wire damping ratio; the generalized mass calculation formula of the windward and windward side insulator strings is:

The generalized stiffness calculation formulas of the windward and windward side insulator strings are:

The generalized damping calculation formula of the windward and windward side insulator strings is:

Among them, m _in is the unit height mass of the insulator string; D _in is the windward outer diameter of the insulator string; the vibration type of the insulator string

Hl _in ≤z≤H; ζ _in is the damping ratio of the insulator string;

l _in is the length of the insulator; among them, the calculation formulas of the generalized mass, generalized stiffness and generalized damping corresponding to the cable structure system are:

In the present invention, the subscript ci represents a cable structure.

S23: Construct the cable structure system combined with the tower-tower structure to form a simplified calculation model of the tower-line coupling based on the data obtained in step S22; S24: Based on the tower-tower structure to form a simplified calculation model of the tower-line coupling, obtain the downwind displacement of the tower under the super-large spanning tower-line system The mean square value of the resonance component and the mean square value of the resonance component of the downwind displacement of the tower when a single tower is used; thus the proportional formula of the two is obtained; the calculation formula of the mean square value of the resonance component of the downwind displacement of the tower under the tower line system is: :

λ _n =n _ci / _nt ;

杆塔1阶模态的振型φ_t(z)＝(z/H)²，0≤z≤H；

The mode shape of the first-order mode of the tower φ _t (z)=(z/H) ² , 0≤z≤H;

为杆塔的广义质量，

M_ca为横担的质量，m_t(z)为随高度变化的杆塔单位高度质量；coh(z₁,z₂)为z₁和z₂高度处两点的脉动风速的相干函数；S_f(n_t)为归一化风速谱，n_t为杆塔脉动风速的频率；

σ_v'为脉动风速的标准差；

为索结构与杆塔的广义质量比值，

λ_n为索结构与杆塔的频率比值；λ_n＝n_ci/n_t；导线悬挂于杆塔的顶部，

ζ_t为总阻尼比；ζ_t＝ζ_st+ζ_at；ζ_st为杆塔结构阻尼比；ω_t为杆塔无阻尼振动的圆频率；δ_ci为索结构总阻尼比，近视取导线阻尼比，δ_ci≈ζ_c，ζ_c＝ζ_sc+ζ_ac；

is the generalized mass of the tower,

M _ca is the mass of the cross arm, m _t (z) is the mass per unit height of the tower that varies with height; coh(z ₁ , z ₂ ) is the coherence function of the fluctuating wind speed at the heights of z ₁ and z ₂ ; S _f (n _t ) is the normalized wind speed spectrum, and n _t is the frequency of the pulsating wind speed of the tower;

σ _v' is the standard deviation of the fluctuating wind speed;

is the generalized mass ratio of the cable structure to the tower,

λ _n is the frequency ratio between the cable structure and the tower; λ _n =n _ci /n _t ; the wire is suspended on the top of the tower,

ζ _t is the total damping ratio; ζ _t = ζ _st + ζ _at ; ζ _st is the damping ratio of the tower structure; ω _t is the circular frequency of the undamped vibration of the tower; δ _ci is the total damping ratio of the cable structure. δ _ci ≈ζ _c , ζ _c =ζ _sc +ζ _ac ;

随高度变化的平均风速，σ_v'为脉动风速的标准差；ρ _a is the air density, μ _s (z) is the coefficient of variation of wind pressure with height; b _s (z) is the width of the windward surface that varies with height;

The mean wind speed that varies with height, σ _v' is the standard deviation of the fluctuating wind speed;

A_s,ca为横担的挡风面积；所述单塔时杆塔顺风向位移共振分量的均方值为： _ζat is the aerodynamic damping ratio of the tower;

A _{s, ca} is the windshield area of the cross arm; the mean square value of the resonance component of the downwind displacement of the tower during the single tower is:

The proportional formula of the resonance component of the downwind displacement of the tower under the tower line system and the resonance component of the downwind displacement of the tower when the single tower is:

S25: Based on the calculation formula obtained in step S24, deduce the calculation formula of the equivalent damping coefficient of the tower line after the transmission line is suspended from the super-large spanning tower, and calculate the equivalent damping coefficient of the tower in the tower line system. The steps of the calculation formula are: the equivalent damping ratio of the tower after the suspension wire is:

对于输电塔线体系而言，索结构为柔性体系，卓越频率远小于杆塔的频率；则忽略λ_n的高阶项；杆塔的阻尼比约为0.01，索结构的阻尼比小于1，则忽略

项；导线悬挂于杆塔的顶部，

故悬挂导线后塔线等效阻尼系数的计算公式为：

Among them, the relationship between ρ and ζ _e is:

For the transmission tower line system, the cable structure is a flexible system, and the predominant frequency is much lower than the frequency of the tower; the higher-order term of λ _n is ignored; the damping ratio of the tower is about 0.01, and the damping ratio of the cable structure is less than 1, it is ignored

item; the wire hangs from the top of the tower,

Therefore, the calculation formula of the equivalent damping coefficient of the tower wire after the suspension wire is as follows:

超高大跨越塔的总高度H；跟开b₁；横担个数n_c；横担平均外伸长度

自立式输电塔分为横隔面、横担和剩余塔身3部分；横隔面、横担、剩余塔身的质量和挡风面积沿高度的分布规律不同，在计算过程中需要区别对待。S312：构建超高大跨越塔的风荷载的计算模型，通过水平均布荷载作用下结构的挠曲线获得超高大跨越塔0°风向角的1阶侧弯振型φ₁(z)；

z为实际高度值。对于该弯曲振型，有如下积分关系：

S313：根据荷载规范引入背景分量因子B_z(z)，进而计算超高输电塔的脉动风荷载在水平方向的相关系数ρ_x；比较超高输电塔塔高和梯度风高度，计算脉动风荷载在竖直方向的相关系数ρ_z；根据荷载规范引入并计算共振分量因子R；确定地面粗糙度指数α；峰值因子g_s；10m高度处的湍流度I₁₀；In a further technical solution, the step of obtaining the wind vibration coefficient β(z) of the super-large spanning tower of the tower-line system in step S3 is as follows: S311: According to the physical parameters of the super-large spanning tower in step S1, determine the roughness of the ground where the super-large spanning tower is located. Degree category, set the average speed at a height of 10m

Total height H of the super-high and large spanning tower; follow-up b ₁ ; number of cross arms n _c ; average outreach length of cross arms

The self-supporting transmission tower is divided into three parts: the cross-section, the cross-arm and the remaining tower body; the mass of the cross-section, the cross-arm, and the remaining tower body and the distribution law of the wind-shielding area along the height are different, which need to be treated differently in the calculation process. S312: Build a calculation model for the wind load of the super-large spanning tower, and obtain the first-order side bending mode φ ₁ (z) of the 0° wind direction angle of the super-large spanning tower through the deflection line of the structure under the horizontally distributed load;

z is the actual height value. For this bending mode shape, there is the following integral relationship:

S313: Introduce the background component factor B _z (z) according to the load specification, and then calculate the correlation coefficient ρ _x of the pulsating wind load of the ultra-high transmission tower in the horizontal direction; compare the tower height and the gradient wind height of the ultra-high transmission tower, and calculate the pulsating wind load Correlation coefficient ρ _z in vertical direction; Introduce and calculate resonance component factor R according to load specification; Determine ground roughness index α; Crest factor g _s ; Turbulence degree I ₁₀ at a height of 10m;

n为脉动风速的频率；Hg is the gradient wind height; ξ ₁ =δ _e ;

n is the frequency of the pulsating wind speed;

S314: Obtain the fitting coefficients k _γ , a _γ , l _γ , m _γ and b _γ of the intermediate variable γ of the background component factor; consider the influence factors of the gradient wind of the ultra-high transmission tower, obtain the wind vibration coefficient and consider the correction of the overall shape change Coefficient θ _v ; consider the gradient wind height factor of the ultra-high transmission tower and the concrete in the steel tube as an additional quality factor;

Obtain the correction coefficient θ _l , the correction coefficient θ _l is the product of the correction coefficient θ _a of the wind vibration coefficient considering the additional area and the correction coefficient θ _m of the wind vibration coefficient considering the additional mass;

S315: Considering the concrete in the steel tube as an additional mass factor, obtain the correction coefficient θ _b (z) of the wind vibration coefficient of the remaining tower body considering the local shape change, and the wind vibration coefficient of the cross arm considering the local shape change The correction coefficient θ _b (z _I ) and the wind vibration coefficient of the diaphragm, the correction factor θ _b (z _J ) considering the local shape change;

S316: According to the actual height value z of the tower body, the background component factor Bz(z) at the height z is correspondingly obtained according to the correction coefficient obtained in step S315;

μ _zg is the wind pressure height variation coefficient at the gradient wind height;

g_s为峰值因子，其根据荷载规范取值。S317: Calculate the wind vibration coefficient β(z); the expression of the wind vibration coefficient is:

g _s is the crest factor, which is valued according to the load specification.

By dividing the transmission tower into three parts: the remaining tower body, the diaphragm and the cross arm, the calculation model of the design wind vibration coefficient of the transmission tower is gradually improved by considering the influence of the three parts respectively. The purpose of simplified calculation is achieved by nonlinear fitting of complex multi-integral functions and the establishment of a simplified model of the spatial distribution relationship among the remaining towers, cross-arms and diaphragms. Considering the gradient wind height factor of the ultra-high transmission tower and the concrete in the steel tube as an additional mass factor, the correction coefficients θ _b , θ _l and θ _η are obtained, and the design formula of the wind vibration coefficient of the transmission tower with cantilevered cross-arm is deduced. The calculation steps are simple and the final design effect is good.

In a further technical solution, the wind vibration coefficient step of the maximum wind deflection angle of the suspended insulator string of the tower-line system is β; S321: According to the physical parameters of the transmission line and the insulator string of the super-large spanning tower-line system in step S1, the gravity and the average wind As the initial condition for the calculation of the wire and the pendant insulator string under the action of the load, the calculation model of the wind deflection angle of the pendant insulator string is determined by the LRC method; the physical parameters of the wire include at least the type of wire, the calculated cross-sectional area of the wire, the elastic modulus of the wire, and the linear density. , the outer diameter of the wire; the physical parameters of the insulator string on the transmission tower at least include the length of the insulator string, the elastic modulus of the insulator string, the quality of the insulator string, and the windshield area of the insulator string.

导线跨度L、平均风荷载作用下B点的顺风向位移

A、B两点间的绝缘子串长度l_AB、导线两端挂点高差h、平均风偏角

坐标原点到导线最低点的水平距离a′、导线最低点到导线末端的水平距离b’。导线在自重状态下为悬链线构型，风荷载作用下表现为几何大变形。以往研究表明输电塔对导线风振响应的影响小。为简化计算，忽略杆塔的影响，将绝缘子在杆塔的挂点视为固定铰支座，从而对挂线悬垂绝缘子串进行风偏角研究。In the calculation model of the wind deflection angle of the suspended insulator string, the connection point A of the wire and the insulator string, the end point B of the suspended insulator string, the moving point B' of the end point of the insulator string in the dynamic state, and the point B' in the dynamic state are set. Wind declination caused by moving to B"

Downwind displacement of point B under the action of conductor span L and average wind load

The length of the insulator string between points A and B, l _AB , the height difference h of the hanging points at both ends of the wire, and the average wind deflection angle

The horizontal distance a' from the coordinate origin to the lowest point of the wire, and the horizontal distance b' from the lowest point of the wire to the end of the wire. The wire has a catenary configuration under its own weight, and it shows a large geometric deformation under the action of wind load. Previous studies have shown that the transmission tower has little effect on the wind vibration response of the conductor. In order to simplify the calculation and ignore the influence of the tower, the hanging point of the insulator on the tower is regarded as a fixed hinge support, so that the wind deflection angle of the hanging insulator string is studied.

式中，(:,i) 表示矩阵的第i列元素；

为等效背景风压；

为平均风荷载；导线在风荷载作用下的振动方程矩阵表达式为：

S322: Calculate the equivalent static wind load per unit area of the conductors between the transmission towers in the super-large spanning tower-line system; the calculation formula of the equivalent static wind load p _ESWL per unit area of the conductors between the transmission towers is:

In the formula, (:,i) represents the i-th column element of the matrix;

is the equivalent background wind pressure;

is the average wind load; the matrix expression of the vibration equation of the conductor under the action of wind load is:

Y′分别为脉动风荷载作用下导线节点顺风向的加速度、速度和位移；

为平均风荷载作用下导线节点顺风向的位移。导线为轻质柔性结构，强风荷载下表现为：1) 结构发生大变形，几何非线性明显；2)结构受力与位移之间不呈线性关系；3)动力荷载作用下，结构为时变刚度。因此，上述为变系数微分方程，不能采用线性叠加原理求解。来流风荷载引起导线的风振响应同样可以分解为平均响应和脉动响应两部分。In the formula,

Y′ are the acceleration, velocity and displacement of the conductor node in the downwind direction under the action of fluctuating wind load, respectively;

is the downwind displacement of the conductor node under the action of the average wind load. The conductor is a light and flexible structure, and under strong wind load, it is shown as follows: 1) The structure undergoes large deformation, and the geometric nonlinearity is obvious; 2) The relationship between the force and displacement of the structure is not linear; 3) Under the action of dynamic load, the structure is time-varying stiffness. Therefore, the above are differential equations with variable coefficients, which cannot be solved by the principle of linear superposition. The wind vibration response of the conductor caused by the incoming wind load can also be decomposed into two parts: the average response and the pulsating response.

M is the mass matrix; C is the damping matrix; K is the stiffness matrix; L _s is the nodal subordinate area matrix;

The matrix expression of the vibration equation of the conductor under the action of pulsating wind load is:

The above scheme adopts the equivalent static wind load of the LRC method. The wire is a light and flexible structure, and under strong wind load, it is shown as follows: 1) The structure undergoes large deformation and the geometric nonlinearity is obvious; 2) The relationship between the force and the displacement of the structure is not linear; 3) Under the action of dynamic load, the structure is time-varying stiffness.

Therefore, taking the average wind state of the conductor as the initial calculation condition, the matrix expression of the vibration equation of the conductor under the action of fluctuating wind load can be obtained.

The matrix expression of the vibration equation of the wire under the action of wind load cannot be solved by the linear superposition principle. The wind vibration response of the conductor caused by the incoming wind load can also be decomposed into two parts: the average response and the pulsating response.

According to the above content, the equivalent static wind load can be obtained to calculate the maximum wind deflection angle of the suspended insulator string; the calculation formula of the equivalent static wind load to calculate the maximum wind deflection angle of the suspended insulator string is:

为脉动风荷载作用下B点的顺风向峰值位移；l_AB为A、B两点间的绝缘子串长度；

为平均风荷载作用下B点的顺风向位移，

为平均风偏角；具体计算公式为：

In the formula,

is the downwind peak displacement of point B under the action of pulsating wind load; l _AB is the length of the insulator string between points A and B;

is the downwind displacement of point B under the average wind load,

is the average wind deflection angle; the specific calculation formula is:

G_v分别为目标点处悬垂绝缘子串的平均风荷载和竖向重力荷载；

W_v分别为目标点处导线传递给悬垂绝缘子串的平均风荷载和竖向荷载。

G _v are the average wind load and vertical gravity load of the suspended insulator string at the target point, respectively;

W _v are the average wind load and vertical load transferred by the conductor at the target point to the suspended insulator string, respectively.

的计算公式为：

Average wind load imparted by the conductor at the target point to the pendant insulator string

The calculation formula is:

式中，N_c为分裂导线的个数；

为单根导线单位线长的一致平均风荷载；Γ_h为导线在水平档距内的线长，计算方式为对公式

在水平档距进行曲线积分；其中，

In the formula, N _c is the number of split wires;

is the uniform average wind load per unit line length of a single conductor; Γ _h is the line length of the conductor within the horizontal span, and the calculation method is the pair formula

Curve integration is performed over the horizontal span; where,

为荷载p′与响应y_B的相关系数；

为初始条件下响应y_B的影响线；In the formula,

is the correlation coefficient between the load p' and the response y _B ;

is the influence line of the response y _B under the initial conditions;

When the transmission tower is an ultra-high transmission tower, the calculation formula of the vertical load W _v transmitted by the wire at the target point to the hanging insulator string is: W _v =P _v Γ _l +T _vl +P _v Γ _r + T _vr ;

T_vl＝0；当导线在跨内的几何线形的斜率处处不为0时：

Among them, Γ _l and Γ _r are the calculated line lengths of the left and right spans of the target point respectively; T _vl and T _vr are the vertical components of the tension at the lowest point of the conductors on the left and right spans of the target point, respectively; When the slope of the geometric line is 0:

T _vl = 0; when the slope of the geometrical line shape of the wire is not 0 everywhere in the span:

In the formula, _Tw is the horizontal tension of a single wire under the average wind condition, and the calculation formula is: _Tw = σ _o4 A _c ;

式中，下标“3”和“4”分别表示无风状态和平均风状态；A_c为导线的受力面积；E_c为导线的弹性模量；γ_c为导线的综合比载，

γ_w为平均风压比载，

in,

In the formula, the subscripts "3" and "4" represent the windless state and the average wind state respectively; A _c is the stress area of the wire; E _c is the elastic modulus of the wire; γ _c is the comprehensive specific load of the wire,

_γw is the average wind pressure specific load,

为导线单位线长的平均风荷载，计算公式为：

is the average wind load per unit line length of the conductor, and the calculation formula is:

l _r represents the span; β _r represents the height difference angle

S323: Calculate the wind vibration coefficient β of the maximum wind deflection angle of the pendant insulator string of the tower-line system;

∑_C表示对计算域内的元素进行求和；Γ_c为计算域内导线的线长；

为平均风荷载；

为等效背景风压。

∑ _C means summing the elements in the computational domain; Γ _c is the line length of the wire in the computational domain;

is the average wind load;

is the equivalent background wind pressure.

A further technical solution is: the calculation steps of the wind load fluctuation reduction coefficient ε _c of the tower-line system are:

S41: Construct the calculation model of the super-large spanning tower line system, and obtain the calculation model diagram of the tower line system;

其中，ω₀为基本风压；μ_z(H)为风压随超高大跨越塔高度变化系数；μ_s(H)为杆塔随高度阻力系数；b_s(H)随高度变化的迎风面宽度；g_s为峰值因子；ω₁为顺风向1阶模态的自振圆频率；m(H)为随高度变化的单位高度质量；S42: According to the ultra-high and large spanning tower, establish the relationship between the tower response and the tower wind vibration coefficient, and obtain the root mean square value σ _ut (H) of the tower top displacement caused by the tower load at the tower height H and the tower wind vibration coefficient β (H) relationship;

Among them, ω ₀ is the basic wind pressure; μ _z (H) is the variation coefficient of wind pressure with the height of the superelevation and large spanning tower; μ _s (H) is the resistance coefficient of the tower with height; b _s (H) The width of the windward surface that changes with the height ; g _s is the crest factor; ω ₁ is the natural circular frequency of the first-order mode in the downwind direction; m(H) is the mass per unit height that varies with height;

When the wire is suspended on the top of the tower, the relationship between the wire and the wind vibration coefficient of the wire is established, and the calculation formula of the root mean square value σ _uc (H) of the tower top displacement caused by the wire load is:

Among them, N _p is the phase number of the wire; μ _sc is the resistance coefficient of the wire; N _c is the number of split wires; D _c is the calculated outer diameter of the sub-wire/ground wire; L _p is the horizontal span; H is the Tower height; E _t is the elastic modulus.

S43: According to the content obtained in step S41, adopt the SRSS method to determine the peak response calculation formula of the tower under the tower-wire system;

为由杆塔平均风荷载引起的杆塔响应；

为由导线平均风荷载引起的杆塔响应；

为塔线体系平均风荷载引起的杆塔响应σ_r为塔线体系下杆塔响应的标准差；g_s为峰值因子；σ_rt为由杆塔脉动风荷载引起的塔体均方根响应；σ_rc为由导线脉动风荷载引起的塔体均方根响应；Among them, the

is the tower response caused by the average wind load of the tower;

is the response of the tower caused by the average wind load of the conductor;

is the tower response caused by the average wind load of the tower line system; σ _r is the standard deviation of the tower response under the tower line system; g _s is the peak factor; σ _rt is the root mean square response of the tower body caused by the fluctuating wind load of the tower line; σ _rc is RMS response of tower body due to fluctuating wind loads on conductors;

S44: Based on the calculation formula of the peak response of the tower under the tower line system in step S43, adopt the tower line separation method, introduce the wind load fluctuation reduction coefficient of the tower, and obtain the equivalent peak response calculation formula of the peak response calculation formula of the tower:

表示杆塔荷载引起的峰值响应，

表示输电线荷载引起的峰值响应。引入ε_c后，杆塔的最大响应可以由两部分荷载引起杆塔最大响应折减后的线性叠加确定。若不考虑ε_c，

表示杆塔荷载引起的峰值响应，

表示输电线荷载引起的峰值响应，此时线性叠加的结果将比实际值偏大。

represents the peak response caused by the tower load,

Represents the peak response due to transmission line loads. After introducing _εc , the maximum response of the tower can be determined by the linear superposition of the reduced maximum response of the tower caused by the two parts of the load. If ε _c is not considered,

represents the peak response caused by the tower load,

Indicates the peak response caused by the load of the transmission line, and the result of linear superposition will be larger than the actual value at this time.

σ_uc表示导线荷载引起塔顶位移的均方根值；σ_ut(H)为随高度变化的杆塔荷载引起塔顶位移的均方根值；S45: Taking the displacement response of the tower top as the target, further update the equivalent peak response calculation formula of the peak response calculation formula of the tower obtained in step S44, and obtain the root mean square value of the tower top displacement caused by the unknown conductor load and the unknown tower The updated calculation formula of the pulsation reduction factor of the root mean square value of the tower top displacement caused by the load:

σ _uc is the root mean square value of the tower top displacement caused by the wire load; σ _ut (H) is the root mean square value of the tower top displacement caused by the tower load that varies with height;

S46: The root mean square value of the tower top displacement caused by the wire load and the root mean square value of the tower top displacement caused by the tower load calculated in step S42 are brought into the updated calculation formula of the pulsation reduction coefficient obtained in step S45, and the pulsation is obtained. The final calculation formula of the reduction factor, and the calculation of the wind load fluctuation reduction factor of the tower;

其中，

in,

The calculation method of the wind load fluctuation reduction factor of the tower considering the coupling effect of the tower line is suitable for the expression of the tower wind load fluctuation reduction coefficient of the ultra-high transmission tower. Therefore, a wind load design method of transmission tower is proposed, which adopts the reduction coefficient of tower wind load fluctuation to consider the influence of tower-line coupling.

In a further technical solution, the calculation formula of the modified wind vibration coefficient β ^* (z) of the super-large spanning tower of the tower-line system and the modified wind-vibration coefficient β ^* of the transmission line of the tower-line system is:

A further technical solution is to calculate the relationship between the design wind load f _ESWL (z) and the modified wind vibration coefficient β ^* (z) of the ultra-high transmission tower in the ultra-high-span tower-line system under the action of the equivalent vibration inertia force:

Among them, ξ ₁ =ξ _e ;

m(z)=m(0) _μm (z);

I_z(z)为z高度处的脉动风湍流密度；

I₁₀为10m高度处的脉动风湍流密度；x′₁为公式

中，n＝n₁时的取值， n₁为输电塔的1阶模态频率；u₁和η_xz1是与风场湍流特性和空间相关性等有关的系数，分别称为综合影响系数和空间相关性折减系数。S _f (n) S _f (n) is the normalized wind speed spectrum,

I _z (z) is the fluctuating wind turbulence density at z height;

I ₁₀ is the fluctuating wind turbulence density at a height of 10m; x′ ₁ is the formula

, the value when n=n ₁ , n ₁ is the first-order modal frequency of the transmission tower; u ₁ and η _xz1 are the coefficients related to the turbulence characteristics and spatial correlation of the wind field, which are called the comprehensive influence coefficient and Spatial correlation reduction factor.

其中，β＝α'β_c；式中，α’为取值小于1的风压不均匀系数；μ_sc为导线阻力系数；β_c为风荷载调整系数，计算风偏角时取1；Dc为子导线/地线的计算外径； Lp为杆塔的水平档距；B₁为覆冰时风荷载的增大系数；ω₀为基本风压；μ_z为风压随高度变化系数；B_l为覆冰时风荷载的增大系数；N_c为分裂导线的个数；θ为风向角。In a further technical solution, the calculation formula for calculating the design wind load W _X of the transmission line based on the tower-line separation method is:

Among them, β=α'β _c ; in the formula, α' is the wind pressure uneven coefficient whose value is less than 1; μ _sc is the resistance coefficient of the wire; β _c is the wind load adjustment coefficient, which is taken as 1 when calculating the wind deflection angle; Dc is the calculated outer diameter of the sub-conductor/ground wire; Lp is the horizontal span of the tower; B ₁ is the increase coefficient of the wind load when icing; ω ₀ is the basic wind pressure; μ _z is the wind pressure variation coefficient with height; B _l is the increase coefficient of wind load during icing; N _c is the number of split conductors; θ is the wind direction angle.

The beneficial effects of the present invention are as follows: the equivalent vibration inertial force method is adopted, the damping coefficient is calculated finely, and the correction situation caused by the coupling effect of the tower line is considered to calculate the design wind load of the ultra-high and large spanning tower in the tower line system. The design wind load of the tower-line system is calculated by the tower-line separation method, and the damping coefficient is considered for refined calculation and the correction caused by the tower-line coupling effect is considered, so that the final designed tower-line system is closer to reality. , high design precision.

Description of drawings

Figure 1 is the calculation model diagram of the tower-line system;

Fig. 2 is the mode shape diagram of wire and insulator string;

Figure 3: Simplified calculation model of tower-line coupling;

Figure 4 is the calculation diagram of the super-large spanning tower;

Fig. 5 is the schematic diagram of the calculation model of the string wind deflection angle of the pendant insulator;

Fig. 6 is the calculation flow chart of the present invention;

Figure 7 is the flow chart of the calculation of the equivalent damping coefficient of the tower in the tower-line system;

Fig. 8 is a flow chart of calculation of wind vibration coefficient of super-high and large spanning towers of tower-line system;

Fig. 9 is a flow chart for calculating the wind vibration coefficient of the maximum wind deflection angle of the pendant insulator string of the tower-wire system;

Fig. 10 is the flow chart of calculation of wind load fluctuation reduction factor of tower-line system;

FIG. 11 is a definition diagram of the wind direction angle.

Detailed ways

The specific embodiments and working principles of the present invention will be further described in detail below with reference to the accompanying drawings.

A calculation method based on the inertial force method and the tower line separation method considering the coupling effect of the tower and the line wind load, it can be seen from Figure 6 that the specific steps are: S1: Build the tower line of the ultra-high and large spanning tower system, and obtain the physical parameters of super-large spanning towers, transmission lines, and insulator strings of the tower-line system; combined with Figure 1, it can be seen that it is a tower-line system with super-large spanning towers.

所述迎风面、被风面导线的广义刚度计算公式为：

所述迎风面、被风面导线的广义阻尼计算公式为：

m_c为单根导线单位线长的质量；单根导线振型

γ_g为导线的自重比载；σ₀为导线的水平初应力；Γ为导线的线长，

ζ_c＝ζ_sc+ζ_ac；ζ_sc为导线结构阻尼比；ζ_ac为导线启动阻尼比；N_c为分裂导线的个数；T_w为平均风状态下单根导线的水平张力；ζ_c为导线阻尼比；S2: Based on the influence factor of the tower-line coupling, according to the equivalent damping coefficient δ _e of the tower in the tower-line system; specifically, with reference to Fig. 7 , it can be seen that the specific steps of step S2 are: S21: According to the superelevation and large spanning tower of step S1 The tower line system, the calculation model diagram of the super-large spanning tower line system is obtained, see Figure 2 for details. The tower in the calculation model of the tower line system is a dense structure, the tower body is a square variable section, the size becomes smaller from bottom to top, and the cross arm is of equal cross section; the two ends of the wire in the calculation model of the tower line system are of equal height, It is connected with the fixed hinge support; the height of the tower in the calculation model of the tower line system is H, the length of the cross arm cantilever is l _ca , the length of the insulator is l _in , and the span of the wire is L; the wire hanging point has no height difference. S22: Set the assumptions of the vibration of the transmission line and the insulator string, and obtain the mode shape diagram of the transmission line and the insulator string in the super-large spanning tower line system, as well as the generalized mass and generalized stiffness of the windward side and the windward side of the transmission line and the insulator string. and generalized damping; combine the transmission line and insulator string in the super-large spanning tower line system to form a cable structure system; the generalized mass calculation formula of the windward side and the windward side conductor is:

The generalized stiffness calculation formula of the windward side and the windward side wire is:

The generalized damping calculation formula of the windward side and the windward side wire is:

m _c is the mass of a single wire per unit line length; the mode shape of a single wire

γ _g is the self-weight specific load of the wire; σ ₀ is the horizontal initial stress of the wire; Γ is the wire length of the wire,

ζ _c = ζ _sc + ζ _ac ; ζ _sc is the damping ratio of the wire structure; ζ _ac is the start-up damping ratio of the wire; N _c is the number of split wires; _Tw is the horizontal tension of a single wire under the average wind condition; ζ _c is the wire damping ratio;

所述迎风面、被风面绝缘子串的广义刚度计算公式为：

所述迎风面、被风面绝缘子串的广义阻尼计算公式为：

其中，m_in为绝缘子串单位高度质量；D_in为绝缘子串迎风外径；绝缘子串振型

H-l_in≤z≤H；ζ_in为绝缘子串阻尼比；

l_in为绝缘子长度；其中，索结构体系对应的广义质量、广义刚度和广义阻尼的计算公式为：

The generalized mass calculation formula of the windward side and the windward side insulator string is:

The generalized stiffness calculation formulas of the windward and windward side insulator strings are:

The generalized damping calculation formula of the windward and windward side insulator strings is:

Among them, m _in is the unit height mass of the insulator string; D _in is the windward outer diameter of the insulator string; the vibration type of the insulator string

Hl _in ≤z≤H; ζ _in is the damping ratio of the insulator string;

l _in is the length of the insulator; among them, the calculation formulas of the generalized mass, generalized stiffness and generalized damping corresponding to the cable structure system are:

所述单塔时杆塔顺风向位移共振分量的均方值为：

S23: Construct the cable structure system combined with the tower-tower structure to form a simplified calculation model of tower-line coupling based on the data obtained in step S22. In this embodiment, the model is shown in Fig. 3; Take the mean square value of the resonance component of the downwind displacement of the tower under the super-large spanning tower line system and the mean square value of the resonance component of the downwind displacement of the tower when a single tower is used; thus the proportional formula of the two is obtained; the tower downwind under the tower line system The proportional formula of the resonance component of the longitudinal displacement and the resonance component of the downwind displacement of the tower in the case of the single tower is:

In the case of the single tower, the mean square value of the resonance component of the downwind displacement of the tower is:

The calculation formula of the mean square value of the resonance component of the downwind displacement of the tower under the tower line system is:

S25: Based on the calculation formula obtained in step S24, deduce the calculation formula of the equivalent damping coefficient of the tower line after the transmission line is suspended from the super-large spanning tower, and calculate the equivalent damping coefficient of the tower in the tower line system.

The formula for calculating the equivalent damping coefficient of the tower in the tower-line system is:

项。对于图3的计算模型，导线悬挂于杆塔的顶部，

此时，公式(1)可以简化为：

For the transmission tower line system, the cable structure is a flexible system, and the predominant frequency is much lower than that of the tower. Therefore, equation (1) can ignore higher-order terms of λ _n . In addition, the damping ratio of the tower is about 0.01, and the damping ratio of the cable structure is less than 1, which can be ignored.

item. For the computational model of Figure 3, the wire is suspended from the top of the tower,

At this point, formula (1) can be simplified as:

超高大跨越塔的总高度H；跟开b₁；横担个数n_c；横担平均外伸长度

S3: It can be seen from Figure 8 that the equivalent damping coefficient δ _e of the tower in the tower line system obtained in step S2 is replaced by the damping coefficient ζ ₁ , and the wind vibration coefficient β(z) of the ultra-high and large spanning tower of the tower line system is obtained; In this embodiment, it can be seen with reference to Fig. 4 that it is a calculation diagram of the super-large spanning tower; specific steps: S311: According to the physical parameters of the super-large spanning tower in step S1, determine the surface roughness category of the super-large spanning tower, and set Average speed at 10m height

Total height H of the super-high and large spanning tower; follow-up b ₁ ; number of cross arms n _c ; average outreach length of cross arms

S312: Build a calculation model for the wind load of the super-large spanning tower, and obtain the first-order side bending mode φ ₁ (z) of the 0° wind direction angle of the super-large spanning tower through the deflection line of the structure under the horizontally distributed load;

z为实际高度值

z is the actual height value

S313: Introduce the background component factor B _z (z) according to the load specification, and then calculate the correlation coefficient ρ _x of the pulsating wind load of the ultra-high transmission tower in the horizontal direction; compare the tower height and the gradient wind height of the ultra-high transmission tower, and calculate the pulsating wind load Correlation coefficient ρ _z in vertical direction; Introduce and calculate resonance component factor R according to load specification; Determine ground roughness index α; Crest factor g _s ; Turbulence degree I ₁₀ at a height of 10m;

n为脉动风速的频率；Hg is the gradient wind height; ξ ₁ =δ _e ;

n is the frequency of the pulsating wind speed;

S314: Obtain the fitting coefficients k _γ , a _γ , l _γ , m _γ and b _γ of the intermediate variable γ of the background component factor; consider the influence factors of the gradient wind of the ultra-high transmission tower, obtain the wind vibration coefficient and consider the correction of the overall shape change Coefficient θ _v ; consider the gradient wind height factor of the ultra-high transmission tower and the concrete in the steel pipe as an additional mass factor; obtain the correction coefficient θ _l , the correction coefficient θ _l is the wind vibration coefficient considering the additional area correction coefficient θ _a and the wind vibration coefficient considering The product of the correction coefficient θ _m of the additional mass; in this embodiment, the values of the fitting coefficients k _γ and a _γ are obtained in combination with Table 1. Combined with Table 2, the values of m _γ and b _γ can be obtained.

Table 1 Values of k _γ and a _γ

Table 2 Values of l _γ , m _γ and b _γ

Ground Roughness Category A B C D l_γ 3.208 2.818 2.030 1.360 m_γ -3.346 -2.909 -2.067 -1.374 b_γ 229.182 253.879 299.306 341.215

Considering the influence of gradient wind height but not considering the influence of concrete quality, the expression of θ _v is:

取e＝10作为制表的依据，列出的θ_v表，见表3所示

Take e=10 as the basis for tabulation, and the θ _v table listed is shown in Table 3

Table 3 The value of θ _v when the width and depth of the ultra-high transmission towers all change with the same law along the height

The correction coefficient θ _l is the product of the correction coefficient θ _a of the wind vibration coefficient considering the additional area and the correction coefficient θ _m of the wind vibration coefficient considering the additional mass. The specific value is shown in Table 4. The calculation formula is as follows:

Table 4 Values of θ _l for ultra-high transmission towers

S315: Considering the concrete in the steel tube as an additional mass factor, obtain the correction coefficient θ _b (z) of the wind vibration coefficient of the remaining tower body considering the local shape change, and the wind vibration coefficient of the cross arm considering the local shape change The correction coefficient θ _b (z _I ) and the wind vibration coefficient of the diaphragm, the correction factor θ _b (z _J ) considering the local shape change;

S316: According to the actual height value z of the tower body, the background component factor Bz(z) at the height z is correspondingly obtained according to the correction coefficient obtained in step S315;

μ _zg is the wind pressure height variation coefficient at the gradient wind height;

S317: Calculate the wind vibration coefficient β(z); the expression of the wind vibration coefficient is:

In this embodiment, it can be seen with reference to Fig. 9 that the steps of the wind vibration coefficient β of the maximum wind deflection angle of the pendant insulator string of the tower-wire system are:

S321: According to the physical parameters of the transmission line and the insulator string of the super-large spanning tower line system in step S1, the wind deflection angle of the pendant insulator string is determined by the LRC method under the action of gravity and average wind load as the initial conditions for the calculation of the conductor and the pendant insulator string calculation model;

S322: Calculate the equivalent static wind load per unit area of the conductors between the transmission towers in the super-large spanning tower-line system;

The calculation formula of the equivalent static wind load p _ESWL per unit area of the conductor between the transmission towers is:

为等效背景风压；

为平均风荷载；In the formula, (:, i) represents the i-th column element of the matrix;

is the equivalent background wind pressure;

is the average wind load;

The matrix expression of the vibration equation of the wire under the action of wind load is:

Y′分别为脉动风荷载作用下导线节点顺风向的加速度、速度和位移；

为平均风荷载作用下导线节点顺风向的位移；In the formula,

Y′ are the acceleration, velocity and displacement of the conductor node in the downwind direction under the action of fluctuating wind load, respectively;

is the downwind displacement of the conductor node under the action of the average wind load;

M is the mass matrix; C is the damping matrix; K is the stiffness matrix; L _s is the nodal subordinate area matrix;

等效静力风荷载计算悬垂绝缘子串的最大风偏角的计算公式为：

式中，

为脉动风荷载作用下B点的顺风向峰值位移

l_AB为A、B两点间的绝缘子串长度；

The matrix expression of the vibration equation of the conductor under the action of pulsating wind load is:

The formula for calculating the maximum wind deflection angle of a pendant insulator string by equivalent static wind load is:

In the formula,

is the downwind peak displacement of point B under the action of fluctuating wind load

l _AB is the length of the insulator string between points A and B;

为平均风荷载作用下B点的顺风向位移，

is the downwind displacement of point B under the average wind load,

为平均风偏角；具体计算公式为：

is the average wind deflection angle; the specific calculation formula is:

G_v分别为目标点处悬垂绝缘子串的平均风荷载和竖向重力荷载；

W_v分别为目标点处导线传递给悬垂绝缘子串的平均风荷载和竖向荷载；

G _v are the average wind load and vertical gravity load of the suspended insulator string at the target point, respectively;

W _v are the average wind load and vertical load transferred by the conductor at the target point to the suspended insulator string, respectively;

的计算公式为：

Average wind load imparted by the conductor at the target point to the pendant insulator string

The calculation formula is:

式中，Nc为分裂导线的个数；

为单根导线单位线长的一致平均风荷载；Γ_h为导线在水平档距内的线长，计算方式为对公式

在水平档距进行曲线积分；其中，

In the formula, Nc is the number of split wires;

is the uniform average wind load per unit line length of a single conductor; Γ _h is the line length of the conductor within the horizontal span, and the calculation method is the pair formula

Curve integration is performed over the horizontal span; where,

为荷载p′与响应y_B的相关系数；

为初始条件下响应y_B的影响线；In the formula,

is the correlation coefficient between the load p' and the response y _B ;

is the influence line of the response y _B under the initial conditions;

When the transmission tower is an ultra-high transmission tower, the calculation formula of the vertical load W _v transmitted by the wire at the target point to the hanging insulator string is: W _v =P _v Γ _l +T _vl +P _v Γ _r + T _vr ;

T_vl＝0；当导线在跨内的几何线形的斜率处处不为0时：

Among them, Γ _l and Γ _r are the calculated line lengths of the left and right spans of the target point respectively; T _vl and T _vr are the vertical components of the tension at the lowest point of the conductors on the left and right spans of the target point, respectively; When the slope of the geometric line is 0:

T _vl = 0; when the slope of the geometrical line shape of the wire is not 0 everywhere in the span:

In the formula, _Tw is the horizontal tension of a single wire under the average wind condition, and the calculation formula is: _Tw = σ _o4 A _c ;

式中，下标“3”和“4”分别表示无风状态和平均风状态；A_c为导线的受力面积；E_c为导线的弹性模量；γ_c为导线的综合比载，

γ_w为平均风压比载，

in,

In the formula, the subscripts "3" and "4" represent the windless state and the average wind state respectively; A _c is the stress area of the wire; E _c is the elastic modulus of the wire; γ _c is the comprehensive specific load of the wire,

_γw is the average wind pressure specific load,

为导线单位线长的平均风荷载，计算公式为：

is the average wind load per unit line length of the conductor, and the calculation formula is:

l _r represents the span; β _r represents the height difference angle;

S323: Calculate the wind vibration coefficient of the pendant insulator string;

为平均风荷载；

为等效背景风压。∑ _C means summing the elements in the computational domain; Γ _c is the line length of the wire in the computational domain;

is the average wind load;

is the equivalent background wind pressure.

In this embodiment, the calculation formula for calculating the wind vibration coefficient β of the transmission line of the tower-line system is:

∑_C表示对计算域内的元素进行求和；Γ_c为计算域内导线的线长；

为平均风荷载；

为等效背景风压。

∑ _C means summing the elements in the computational domain; Γ _c is the line length of the wire in the computational domain;

is the average wind load;

is the equivalent background wind pressure.

In this embodiment, the expression for the standard value of the horizontal wind load of the conducting/grounding wire of DL/T 5154 is:

其中，β＝α'β_c；

Wherein, β=α'β _c ;

In the formula, α′ is the wind pressure non-uniformity coefficient whose value is less than 1; μ _sc is the resistance coefficient; β _c is the wind load adjustment coefficient, which is taken as 1 when calculating the wind _deflection angle; diameter; L _p is the horizontal span of the tower; B _l is the increase coefficient of wind load when ice is covered. ω ₀ is the basic wind pressure; μ _z is the variation coefficient of wind pressure with height; B _l is the increase coefficient of wind load when icing; N _c is the number of split conductors; θ is the wind direction angle.

In the present invention, referring to FIG. 11 , it can be defined that the wind direction angle θ=0° when the incoming wind is parallel to the axial direction of the cross arm, and the wind direction angle θ=90° when the incoming wind is parallel to the direction of the conductor. Among them, the x-direction represents the axial direction of the cross arm, and the y-direction represents the straight-line direction.

The wind vibration coefficient does not change much with the wind direction angle, and the influence of the wind direction angle on the wind vibration coefficient of the tower body and the cross arm wind vibration coefficient is opposite, which can be offset for the whole tower. In the power-related standards, only the wind vibration coefficient of the transmission tower under the 0o wind direction angle is considered. Therefore, the influence of wind direction angle on the wind vibration coefficient can be ignored, and the equivalent static wind load at other wind direction angles is determined by the wind load distribution coefficient in DL/T 5154.

Among them, power-related standards include: GB 50545-2010. Design specifications for 110kV~750kV overhead transmission lines [S]. Beijing: China Planning Press, 2010; GB 50665-2011. Design specifications for 1000kV overhead transmission lines [S]. Beijing: China Planning Publishing House, 2011; DL/T 5154-2012. Technical Specifications for the Design of Tower Structures for Overhead Transmission Lines [S]. Beijing: China Planning Press, 2012; DL/T 5504-2015. Technical Specifications for Large-Span Design of UHV Overhead Transmission Lines [S]. Beijing: China Planning Press, 2015.

采用LRC计算的β不是常数，为方便设计使用，根据p_ESWL的分布特性，采用平均化方式处理，计算一致β。p_ESWL在目标点位置凸出，在远离目标点位置逼近于

为非均匀分布。为此，设定计算域，将目标点的等效静力风荷载在计算域内进行平均化处理。当目标点与邻近杆塔导线挂点的高差为0时，选取目标点水平档距为其计算域。有高差时，目标点位置处的等效静力风荷载显得更加凸出，从而选取目标点左右1/4跨为其计算域。The physical meaning of α′β _c is the same as that of β in the load specification, and the wind dynamic effect of pulsation is considered. The equivalent static wind load of the conductor/earth wire is determined by multiplying the average wind load taking into account wind pressure inhomogeneity by β _c . Therefore, α'β _c =β. According to the physical meaning,

The β calculated by LRC is not a constant. For the convenience of design and use, according to the distribution characteristics of p _ESWL , the average method is used to calculate the consistent β. p _ESWL protrudes at the target point, and is close to

is a non-uniform distribution. To this end, a computational domain is set, and the equivalent static wind loads at the target point are averaged in the computational domain. When the height difference between the target point and the hanging point of the adjacent tower wire is 0, the horizontal span of the target point is selected as its calculation domain. When there is a height difference, the equivalent static wind load at the position of the target point is more prominent, so the left and right 1/4 span of the target point is selected as its computational domain.

S4: Considering the tower-line coupling effect, obtain the wind load fluctuation reduction coefficient _εc of the tower-line system, and it can be seen from Figure 10, the details are: S41: Build the calculation model of the super-large spanning tower-line system, and obtain the calculation model of the tower-line system The model diagram is shown in Figure 1; the tower in the calculation model of the tower line system is a dense structure, the tower body is a square variable section, the size becomes smaller from bottom to top, and the cross arm is of equal section; in the calculation model of the tower line system The two ends of the wire have the same height and are connected to the fixed hinge support; the height of the tower in the calculation model of the tower line system is H, the length of the cross arm cantilever is l _ca , the length of the insulator is l _in , and the wire span is L. The wire hanging point has no height difference;

S42: According to the ultra-high and large spanning tower, establish the relationship between the tower response and the tower wind vibration coefficient, and obtain the root mean square value σ _ut (H) of the tower top displacement caused by the tower load at the tower height H and the tower wind vibration coefficient β (H) When the wire is suspended on the top of the tower, the relationship between the wire and the wind vibration coefficient of the wire is established, and the calculation formula of the root mean square value σ _uc (H) of the tower top displacement caused by the wire load is obtained;

The relationship between the root mean square value σ _ut (H) of the tower top displacement caused by the tower load at the tower height H and the tower wind vibration coefficient β (H) is:

Among them, ω ₀ is the basic wind pressure; μ _z (H) is the variation coefficient of wind pressure with the height of the ultra-high single tower; μ _s (H) is the resistance coefficient of the tower with the height; b _s (H) The width of the windward surface that changes with the height ; g _s is the crest factor; ω ₁ is the natural circular frequency of the first-order mode in the downwind direction; m(H) is the mass per unit height that varies with height;

The calculation formula of the root mean square value σ _uc (H) of the tower top displacement caused by the wire load is:

Among them, N _p is the phase number of the conductor; μ _sc is the resistance coefficient of the conductor; N _c is the number of split conductors; D _c is the calculated outer diameter of the sub-conductor/ground wire; L _p is the horizontal span; H is the tower height height; E _t is the elastic modulus;

S43: According to the content obtained in step S41, adopt the SRSS method to determine the peak response calculation formula of the tower under the tower-wire system;

为由杆塔平均风荷载引起的杆塔响应；

为由导线平均风荷载引起的杆塔响应；

为塔线体系平均风荷载引起的杆塔响应σ_r为塔线体系下杆塔响应的标准差；g_s为峰值因子；σ_rt为由杆塔脉动风荷载引起的塔体均方根响应；σ_rc为由导线脉动风荷载引起的塔体均方根响应；Among them, the

is the tower response caused by the average wind load of the tower;

is the response of the tower caused by the average wind load of the conductor;

is the tower response caused by the average wind load of the tower line system; σ _r is the standard deviation of the tower response under the tower line system; g _s is the peak factor; σ _rt is the root mean square response of the tower body caused by the fluctuating wind load of the tower line; σ _rc is RMS response of tower body due to fluctuating wind loads on conductors;

Based on the peak response calculation formula of the tower under the tower line system in step S43, the tower line separation method is adopted, the wind load fluctuation reduction coefficient of the tower is introduced, and the equivalent peak response calculation formula of the peak response calculation formula of the tower is obtained:

表示杆塔荷载引起的峰值响应，

表示输电线荷载引起的峰值响应

represents the peak response caused by the tower load,

Represents the peak response due to transmission line loads

S45: Taking the displacement response of the tower top as the target, further update the equivalent peak response calculation formula of the peak response calculation formula of the tower obtained in step S44, and obtain the root mean square value of the tower top displacement caused by the unknown conductor load and the unknown tower The updated calculation formula of the pulsation reduction factor of the root mean square value of the tower top displacement caused by the load:

σ _uc is the root mean square value of the tower top displacement caused by the wire load; σ _ut (H) is the root mean square value of the tower top displacement caused by the tower load that varies with height;

S46: The root mean square value of the tower top displacement caused by the wire load and the root mean square value of the tower top displacement caused by the tower load calculated in step S42 are brought into the updated calculation formula of the pulsation reduction coefficient obtained in step S45, and the pulsation is obtained. The final calculation formula of the reduction factor, and the calculation of the wind load fluctuation reduction factor of the tower;

in,

In this embodiment, the calculation formula of the modified wind vibration coefficient β ^* (z) of the super-large spanning tower of the tower-line system and the modified wind-vibration coefficient β ^* of the transmission line of the tower-line system is:

The relationship between the design wind load f _ESWL (z) and the modified wind vibration coefficient β ^* (z) of the ultra-high transmission tower in the ultra-high-span tower-line system calculated under the action of the equivalent vibration inertia force exists:

Among them, ξ ₁ =ξ _e ;

S_f(n)为归一化风速谱，

I_z(z)I_z(z)为z高度处的脉动风湍流密度；

I₁₀为10m高度处的脉动风湍流密度； x′₁为公式

中，n＝n₁时的取值，n₁为输电塔的1阶模态频率；m(z)=m(0) _μm (z);

S _f (n) is the normalized wind speed spectrum,

I _z (z) I _z (z) is the fluctuating wind turbulence density at z height;

I ₁₀ is the fluctuating wind turbulence density at a height of 10m; x′ ₁ is the formula

, the value when n=n ₁ , n ₁ is the first-order modal frequency of the transmission tower;

u ₁ and η _xz1 are coefficients related to wind field turbulence characteristics and spatial correlation, which are called comprehensive influence coefficient and spatial correlation reduction coefficient, respectively.

In this embodiment, the calculation formula for calculating the design wind load W _X of the transmission line based on the tower line separation method is:

Among them, β= _{α'β c} ; α' is the wind pressure unevenness coefficient whose value is less than 1; μ _sc is the resistance coefficient of the wire; β _c is the wind load adjustment coefficient, which is taken as 1 when calculating the wind deflection angle; Calculated outer diameter of conductor/ground wire; L _p is the horizontal span of the tower; B _l is the increase coefficient of wind load when ice is covered; ω ₀ is the basic wind pressure; μ _z is the variation coefficient of wind pressure with height; B _l is the increase coefficient of wind load during icing; N _c is the number of split conductors; θ is the wind direction angle.

In conclusion, the ultra-high and large-span towers can be designed based on the inertial force method and the tower-line separation method considering the wind load of the ultra-high-span tower and the line design influenced by the tower-line coupling.

It should be noted that the above descriptions are not intended to limit the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the present invention, It should also belong to the protection scope of the present invention.

Claims (8)

1. A computing method for ultra-high large-span tower and line wind load based on an inertia force method and a tower line separation method considering tower line coupling influence is characterized in that: the method comprises the following specific steps:

s1: building a tower wire system of the ultrahigh large-span tower, and acquiring physical parameters of the ultrahigh large-span tower, the power transmission line and the insulator string of the tower wire system;

s2: based on tower line coupling influence factors and according to tower equivalent damping coefficients in a tower line system_e；

S3: the equivalent damping coefficient of the pole tower in the tower line system obtained in the step S2_eTo replace the damping coefficient ζ₁Solving the wind vibration coefficient beta (z) of the tower line system ultrahigh large span tower;

calculating the wind vibration coefficient beta of the maximum wind deflection angle of the suspension insulator string of the tower-line system by considering linear and line length influence factors;

the method comprises the following steps of calculating the wind vibration coefficient beta (z) of the tower line system ultrahigh spanning tower:

s311: according to the physical parameters of the ultrahigh large span tower in the step S1, the ground roughness category of the ultrahigh large span tower is determined, and the average speed division at the height of 10m is set

The total height H of the ultrahigh large span tower; heel lift b₁(ii) a Number of crossarms n_c(ii) a Average overhang length of cross arm

S312: constructing a calculation model of wind load of the ultra-high large-span tower, and obtaining a 1-order side bending vibration mode phi of the 0-degree wind direction angle of the ultra-high large-span tower through a deflection line of a structure under the action of horizontally uniformly distributed load₁(z)；

z is the actual height value

S313: introducing a background component factor B according to a load specification_z(z) and further calculating a correlation coefficient rho of the fluctuating wind load of the ultrahigh power transmission tower in the horizontal direction_x(ii) a Comparing the tower height of the ultrahigh power transmission tower with the gradient wind height, and calculating the correlation coefficient rho of the pulsating wind load in the vertical direction_z(ii) a Introducing and calculating a resonance component factor R according to a load specification; determining a ground roughness index alpha; crest factor g_s(ii) a Turbulence I at a height of 10m₁₀；

Hg is the gradient wind height; xi₁＝_e；

n is the frequency of the pulsating wind speed;

s314: obtaining intermediate variations of background component factorsFitting coefficient k of quantity gamma_γ、a_γ、l_y、m_yAnd b_y(ii) a Considering gradient wind influence factors of the ultrahigh power transmission tower, and solving a correction coefficient theta of wind vibration coefficient considering overall appearance change_v(ii) a Considering the gradient wind height factor of the ultrahigh power transmission tower and the concrete in the steel pipe as an additional quality factor;

calculating a correction coefficient theta_lThe correction coefficient theta_lCorrection factor theta for wind vibration coefficient taking into account additional area_aCorrection factor theta for wind vibration factor taking into account additional mass_mThe product of (a);

s315: considering concrete in the steel pipe as an additional quality factor, and solving theta of a correction coefficient of the wind vibration coefficient of the residual tower body considering local appearance change_b(z) correction factor theta for cross arm wind vibration coefficient considering local shape change_b(z_I) Correction factor theta considering local shape change with wind vibration coefficient of diaphragm_b(z_J)；

S316: according to the actual height value z of the tower body, the background component factor B at the z height is correspondingly obtained according to the correction coefficient obtained in the step S315_z(z)；

μ_zgThe wind pressure height variation coefficient at the gradient wind height is obtained;

s317: calculating a wind vibration coefficient beta (z); wherein, the wind vibration coefficient expression is as follows:

g_sis a peak factor according to the loadStandardizing values;

s4: the tower line coupling effect is considered, and the wind load pulsation reduction coefficient of a tower line system is obtained_c；

S5: according to the wind load fluctuation reduction coefficient of the tower-line system obtained in the step S4, the wind vibration coefficient of the tower-line system ultrahigh large crossing tower and the wind vibration coefficient beta of the wind deflection angle in the step S3 are corrected and calculated to obtain the corrected wind vibration coefficient beta of the tower-line system ultrahigh large crossing tower^*(z) corrected wind vibration coefficient beta of tower line system transmission line^*；

S6: based on a tower line separation method, calculating the design wind load of an ultrahigh power transmission tower and the design wind load W of a large-span power transmission line in an ultrahigh-span tower line system under the action of equivalent vibration inertia force_X。

2. The method for calculating the line wind load of the ultra-high large-span tower based on the inertia force method and the tower line separation method and considering the tower line coupling influence is characterized in that: the specific steps of step S2 are:

s21: obtaining a calculation model diagram of the line system of the ultra-high large crossing tower according to the line system of the ultra-high large crossing tower in the step S1;

the tower in the tower line system calculation model is of a compact structure, the tower body is a square variable cross section, the size of the tower body is reduced from bottom to top, and the cross arm is of an equal cross section; two ends of a lead in the tower line system calculation model are equal in height and are connected with the fixed hinge support; the height of a tower in the tower wire system calculation model is H, and the length of a cross arm cantilever is l_caInsulator length is l_inThe wire span is L; no height difference of wire hanging point

S22: setting the assumed conditions of the vibration of the transmission line and the insulator string to obtain the vibration pattern diagram of the transmission line and the insulator string in the ultra-high large-span tower line system, and the generalized mass, the generalized rigidity and the generalized damping of the transmission line and the insulator string on the windward side and the windward side; combining the transmission lines and the insulator strings in the ultrahigh large-span tower line system to form a cable structure system;

the generalized mass calculation formula of the windward side and windward side wires is as follows:

the calculation formula of the generalized stiffness of the wires on the windward side and the windward side is as follows:

the generalized damping calculation formula of the wires on the windward side and the windward side is as follows:

m_cthe mass of a unit wire length of a single wire; single wire vibration mode

γ_gThe dead weight of the wire is compared with the load; sigma₀Is the horizontal initial stress of the wire; is the length of the wire of the lead,

ζ_c＝ζ_sc+ζ_ac；ζ_scthe damping ratio of the wire structure is adopted; zeta_acStarting a damping ratio for the wire; n is a radical of_cThe number of the split conductors; t is_wThe horizontal tension of a single wire in an average wind state; zeta_cIs the wire damping ratio;

the generalized mass calculation formula of the insulator string on the windward side and the windward side is as follows:

the calculation formula of the generalized rigidity of the insulator strings on the windward side and the windward side is as follows:

the generalized damping calculation formula of the insulator string on the windward side and the windward side is：

Wherein m is_inThe insulator string has unit height mass; d_inThe insulator string is windward outer diameter; insulator string vibration mode

H-l_in≤Z≤H；ζ_inThe damping ratio of the insulator string is;

l_inis the length of the insulator; the calculation formulas of the generalized mass, the generalized stiffness and the generalized damping corresponding to the cable structure system are as follows:

s23: constructing a cable structure system by the data obtained in the step S22 and combining with a tower structure to form a tower-line coupling simplified calculation model;

s24: forming a tower line coupling simplified calculation model based on a tower structure, and solving a mean square value of a resonance component of downwind displacement of the tower under an ultra-high and large span tower line system and a mean square value of the downwind displacement resonance component of the tower during single tower; thereby obtaining a proportional expression of the two;

s25: and (4) deriving a calculation formula of the tower wire equivalent damping coefficient after the transmission line is suspended by the ultra-high large-span tower based on the calculation formula obtained in the step S24, and calculating the tower equivalent damping coefficient in a tower wire system.

3. The method for calculating the line wind load of the ultra-high large-span tower based on the inertia force method and the tower line separation method and considering the tower line coupling influence is characterized in that: in step S24, the equation for calculating the mean square value of the downwind displacement resonance component of the tower under the tower-line system is:

wherein,

λ_n＝n_ci/n_t；

1-order mode vibration mode phi of tower_t(z)＝(z/H)²，0≤z≤H；

In order to obtain the generalized mass of the tower,

M_camass of cross arm, m_t(z) the mass per unit height of the tower which varies with the height;

coh(z₁,z₂) Is z₁And z₂A coherence function of the pulsating wind speed at two points at height;

S_f(n_t) To normalize the wind velocity spectrum, n_tThe frequency of the tower pulsating wind speed is shown;

σ_v'is the standard deviation of the pulsating wind speed;

is the generalized mass ratio of the cable structure to the tower,

λ_nthe frequency ratio of the cable structure to the tower is obtained; lambda [ alpha ]_n＝n_ci/n_t(ii) a The conducting wire is hung on the top of the tower,

ζ_tis the total damping ratio; zeta_t＝ζ_st+ζ_at；ζ_stThe damping ratio of the tower structure is set; omega_tThe circular frequency of undamped vibration of the tower;_cithe total damping ratio of the cable structure and the damping ratio of the lead are taken as the near vision,_ci≈ζ_c，ζ_c＝ζ_sc+ζ_ac；

ρ_ais the density of air, mu_s(z) is the coefficient of variation of wind pressure with height; b_s(z) the windward width as a function of height;

mean wind speed, σ, as a function of altitude_v'Is the standard deviation of the pulsating wind speed;

ζ_atthe pneumatic damping ratio of the tower is;

A_s，cathe wind shielding area of the cross arm;

the mean square value of the downwind displacement resonance component of the tower in the single tower is as follows:

the ratio of the downwind displacement resonance component of the tower under the tower line system to the downwind displacement resonance component of the tower during the single tower is as follows:

the step of deriving the calculation formula of the tower line equivalent damping coefficient after the wire is suspended in the ultra-high spanning tower in the step S25 is as follows:

the equivalent damping ratio of the tower after the wire is hung is as follows:

where ρ and ζ_eThe relationship of (1) is:

for a transmission tower line system, a cable structure is a flexible system, and the excellent frequency is far less than that of a tower; then ignore λ_nThe higher order terms of (1);

the damping ratio of the tower is about 0.01, the damping ratio of the cable structure is less than 1, and the damping ratio is ignored

An item;

the conductor is suspended on the top of the tower，

Therefore, the calculation formula of the tower line equivalent damping coefficient after the wire is suspended is as follows:_e≈_t+μ_M*λ_{n ci}。

4. the method for calculating the ultra-high and large span tower and the linear wind load based on the inertia force method and the tower line separation method considering the tower line coupling influence according to the claim 1 or 3, is characterized in that: the method for determining the wind vibration coefficient beta of the maximum wind drift angle of the tower line system suspension insulator string comprises the following steps:

s321: determining a calculation model of the wind deflection angle of the suspension insulator string by an LRC method by taking the physical parameters of the transmission line and the insulator string of the ultra-high large spanning tower line system in the step S1 as initial conditions for calculating the lead and the suspension insulator string under the action of gravity and average wind load;

s322: calculating the equivalent static wind load of the unit area of the conducting wires between the power transmission towers in the ultra-high and large spanning tower line system;

equivalent static wind load p of unit area of conducting wire between power transmission towers_ESWLThe calculation formula of (2) is as follows:

wherein (: i) represents the ith column element of the matrix;

equivalent background wind pressure;

the average wind load is obtained; the matrix expression of the vibration equation of the lead under the action of wind load is as follows:

in the formula,

y' is the acceleration, the speed and the displacement of the wire node along the wind direction under the action of the pulsating wind load respectively;

the displacement of the lead joint along the wind direction under the action of average wind load;

m is a quality matrix; c is a damping matrix; a K stiffness matrix; l is_sIs a node dependent area matrix;

the matrix expression of the vibration equation of the lead under the action of fluctuating wind load is as follows:

the calculation formula for calculating the maximum wind drift angle of the suspension insulator string by the equivalent static wind load is as follows:

in the formula,

is the downwind peak displacement of the point B under the action of fluctuating wind load

l_ABA, B is the length of the insulator string between two points;

is the downwind displacement of the point B under the action of average wind load,

is the average wind deflection angle; the specific calculation formula is as follows:

G_vrespectively taking the average wind load and the vertical gravity load of the suspension insulator string at the target point;

W_vrespectively transmitting the average wind load and the vertical load transmitted to the suspension insulator string by the lead at the target point;

average wind load transferred to suspension insulator string by lead at target point

The calculation formula of (2) is as follows:

in the formula, N_cThe number of the split conductors;

the uniform average wind load of the unit wire length of a single wire is obtained;_hthe calculation mode is a pair formula for the line length of the lead in the horizontal span

Performing curve integration at a horizontal span; wherein,

in the formula,

is the load p' and the response y_BThe correlation coefficient of (a);

is a response y in the initial condition_BThe influence line of (1);

when the power transmission tower is an ultrahigh power transmission tower, the lead at the target point transmits a vertical load W to the suspension insulator string_vThe calculation formula of (2) is as follows: w_v＝P_{v l}+T_vl+P_{v r}+T_vr；

Wherein,_l、_rrespectively calculating the lengths of the left span and the right span of the target point; t is_vl、T_vrThe vertical components of the tension at the lowest points of the left and right two cross-wires of the target point are respectively; when the slope of the geometric line shape of the wire at a certain point across the wire is 0:

T_vl0; when the slope of the wire at the geometrical line within the span is not 0:

in the formula, T_wThe calculation formula is the horizontal tension of a single wire in an average wind state: t is_w＝σ_o4A_c；

Wherein,

in the formula, subscripts "3" and "4" represent a no-wind state and an average wind state, respectively; a. the_cThe stress area of the lead is defined; e_cIs the modulus of elasticity of the wire; gamma ray_cIs the comprehensive specific load of the lead wires,

γ_win order to obtain the average wind pressure specific load,

the calculation formula is the average wind load of the unit line length of the lead:

l_rrepresents a span; beta is a_rIs representative of a height difference angle;

s323: calculating the wind vibration coefficient of the suspension insulator string;

∑_crepresenting summing elements within a computational domain;_ccalculating the line length of the wire in the domain;

the average wind load is obtained;

equivalent background wind pressure.

5. The method for calculating the line wind load of the ultra-high large-span tower based on the inertia force method and the tower line separation method and considering the tower line coupling influence is characterized in that: wind load pulsation reduction coefficient of tower-line system_cThe calculation steps are as follows:

s41: constructing a calculation model of an ultra-high and large spanning tower line system, and obtaining a calculation model diagram of the tower line system;

s42: according to the ultrahigh large-span tower, establishing the relation between tower response and tower wind vibration coefficient to obtain the root mean square value sigma of tower top displacement caused by tower load established at the tower height H_ut(H) A relation with tower wind vibration coefficient beta (H); when the lead is hung on the top of the tower, the relation between the lead and the wind vibration coefficient of the lead is established, and the root mean square value sigma of the displacement of the tower top caused by the load of the lead is obtained_uc(H) The calculation formula of (2);

and establishing a root mean square value sigma of tower top displacement caused by tower load at the tower height H_ut(H) The relation between the tower wind vibration coefficient beta (H) is as follows:

wherein, ω is₀The basic wind pressure is obtained; mu.s_z(H) The coefficient of variation of wind pressure along with the height of the ultrahigh single tower is shown; mu.s_s(H) The resistance coefficient of the tower along with the height is obtained; b_s(H) Windward width that varies with height; g_sIs the crest factor; omega₁The natural vibration circle frequency is of 1-order mode in downwind direction; m (H) is the mass per unit height as a function of height;

root mean square value sigma of displacement of tower top caused by lead load_uc(H) The calculation formula of (2) is as follows:

wherein N is_pThe number of phases of the wire; mu.s_scIs the wire resistance coefficient; n is a radical of_cIs the number of split conductors；D_cCalculating the outer diameter of the sub-conductor/ground wire; l is_pIs a horizontal span; h is the height of the tower; e_tIs the modulus of elasticity;

s43: determining a peak response calculation formula of the tower under the tower-wire system by adopting an SRSS method according to the content obtained in the step S41;

wherein, the

Responding to the tower caused by the average wind load of the tower;

responding to the tower caused by the average wind load of the lead;

response sigma of tower caused by mean wind load of tower line system_rThe standard deviation of the tower response under the tower wire system; g_sIs the crest factor; sigma_rtThe root-mean-square response of the tower body caused by the fluctuating wind load of the tower; sigma_rcThe root-mean-square response of the tower body caused by the fluctuating wind load of the lead;

s44: based on the peak response calculation formula of the tower under the tower-wire system of step S43, introducing a tower wind load pulsation reduction coefficient by using a tower-wire separation method, and obtaining an equivalent peak response calculation formula of the tower:

represents the peak response caused by the tower load,

indicating peak response due to transmission line loading

S45: and with the tower top displacement response as a target, further updating the equivalent peak response calculation formula of the tower obtained in the step S44 to obtain a ripple reduction coefficient updating calculation formula of the root mean square value of the tower top displacement caused by the unknown lead load and the root mean square value of the tower top displacement caused by the unknown tower load:

σ_ucthe root mean square value of the displacement of the tower top caused by the load of the lead is represented; sigma_ut(H) The root mean square value of tower top displacement caused by tower load changing along with the height;

s46: substituting the root mean square value of the displacement of the tower top caused by the wire load and the root mean square value of the displacement of the tower top caused by the tower load, which are obtained by calculation in the step S42, into the updated calculation formula of the pulsation reduction coefficient obtained in the step S45 to obtain a final calculation formula of the pulsation reduction coefficient, and calculating the pulsation reduction coefficient of the wind load of the tower;

wherein,

6. the method for calculating the line wind load of the ultra-high large-span tower based on the inertia force method and the tower line separation method and considering the tower line coupling influence is characterized in that:

the corrected wind vibration coefficient beta of the tower line system ultrahigh large-span tower^*(z) and corrected wind vibration coefficient beta of said tower wire system transmission line^*The calculation formula of (2) is as follows:

7. the method for calculating the line wind load of the ultra-high large-span tower based on the inertia force method and the tower line separation method and considering the tower line coupling influence is characterized in that: designed wind load f of ultrahigh power transmission tower in ultrahigh large-span tower line system calculated under action of equivalent vibration inertia force_ESWL(z) and corrected wind vibration coefficient beta^*(z) the relationship:

design wind load f of ultrahigh large-span tower in tower line system of ultrahigh large-span tower_ESWL(z) and corrected wind vibration coefficient beta^*(z) is given by:

wherein ξ₁＝ξ_e；

m(z)＝m(0)μ_m(z)；

S_f(n) is a normalized wind speed spectrum,

I_z(z) is the pulsating wind turbulence density at z-height;

I₁₀a pulsating wind turbulence density at a height of 10 m; x'₁Is a formula of

Where n is n₁Value of time, n₁1 order modal frequency of the power transmission tower;

u₁and η_xz1The coefficients are related to wind field turbulence characteristics, spatial correlation and the like, and are respectively called as a comprehensive influence coefficient and a spatial correlation reduction coefficient.

8. The method for calculating the line wind load of the ultra-high large-span tower based on the inertia force method and the tower line separation method and considering the tower line coupling influence is characterized in that: method for calculating design wind load W of power transmission line based on tower line separation method_XThe calculation formula of (2) is as follows:

wherein β ═ α' β_c(ii) a Alpha' is the uneven coefficient of wind pressure with the value less than 1; mu.s_scIs the wire resistance coefficient; beta is a_cTaking 1 when calculating the wind deflection angle for adjusting the coefficient of the wind load; d_cCalculating the outer diameter of the sub-conductor/ground wire; l is_pThe horizontal span of the tower; b is_lThe coefficient is the increase coefficient of wind load during ice coating; omega₀The basic wind pressure is obtained; mu.s_zThe coefficient of variation of wind pressure along with height is shown; b is_lThe coefficient is the increase coefficient of wind load during ice coating; n is a radical of_cThe number of the split conductors; theta is a wind direction angle.

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