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

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 Download PDF

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CN111985018A
CN111985018A CN202010245501.1A CN202010245501A CN111985018A CN 111985018 A CN111985018 A CN 111985018A CN 202010245501 A CN202010245501 A CN 202010245501A CN 111985018 A CN111985018 A CN 111985018A
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赵爽
晏致涛
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Abstract

The invention discloses a calculation method for a super-high large-span tower and a line wind load based on an inertia force method and a tower line separation method and considering the tower line coupling influence, which comprises the following steps: building a tower line system of the ultrahigh large-span tower, and acquiring physical parameters of the tower line system; based on the tower line coupling influence factors, solving a tower equivalent damping coefficient, a tower line system ultrahigh large spanning tower wind vibration coefficient, a tower line system suspension insulator string maximum wind deflection angle wind vibration coefficient and a tower line system wind load pulsation reduction coefficient; correcting and calculating the wind vibration coefficient of the tower line system ultrahigh large crossing tower and the wind vibration coefficient of the wind deflection angle to obtain the corrected wind vibration coefficient of the tower line system ultrahigh large crossing tower and the corrected wind vibration coefficient of the tower line system power transmission line; based on a tower line separation method, the design wind load of the ultrahigh power transmission tower and the design wind load of the large-span power transmission line in the ultrahigh-span tower line system are calculated under the action of equivalent vibration inertia force. Has the advantages that: the single tower has high design precision and reliability.

Description

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
Technical Field
The invention relates to the technical field, in particular to a calculation method for line wind load and ultrahigh large-span tower based on an inertia force method and a tower line separation method and considering tower line coupling influence.
Background
An ultra-high transmission tower is a transmission tower whose tower height exceeds the gradient wind height, as compared to a conventional transmission tower.
The wind vibration response of the structure can be obtained through power time course analysis, but the wind vibration coefficient calculated by adopting the tower design specification is simple, convenient and time-saving, and the method is still widely adopted by designers at the present stage. The wind vibration coefficient calculated by the specification should have an effect of enabling the wind vibration response of the transmission tower to be equivalent to the actual maximum wind vibration response. The tower design by adopting accurate wind vibration coefficient is the premise of ensuring the normal operation of the transmission line.
The wind load calculated by adopting the design specification of the tower is simple, convenient and time-saving, and the method is still widely adopted by designers at the present stage. The wind load 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 tower design by adopting accurate effective static wind load is the premise of ensuring the normal operation of the transmission line. Among the existing power-related standards: for example, document (1) GB 50545-2010.110 kV-750 kV overhead transmission line design Specification [ S ]. Beijing: Chinese Schedule Press, 2010; (2) GB 50665-2011.1000kV overhead transmission line design Specification [ S ]. Beijing, Chinese Schedule Press, 2011; (3) DL/T5154 + 2012, overhead transmission line tower structure design technical specification [ S ]. Beijing, China plan Press, 2012 and (4) DL/T5504 + 2015, ultra-high voltage overhead transmission line large span design technical specification [ S ]. Beijing, China plan Press, 2015, gives values of single tower wind vibration coefficients below 60m, and recommends that wind vibration coefficients are calculated by adopting load specifications when the wind vibration coefficients are more than 60 m. The wind vibration coefficient of the load specification is suitable for the compact building with regular change of appearance and quality. The power transmission tower is a lattice structure, and the quality of cross arms and cross partition surfaces and the wind shielding area have large influence on the wind vibration coefficient. In addition, the adoption of the steel pipe concrete is not considered when the wind vibration coefficient is calculated according to the load specification. When the equivalent static wind load of the power transmission tower is calculated by adopting a random vibration theory, the expression relates to complex multiple integrals, the appearance and the mass distribution of the power transmission tower are irregular, and the equivalent static wind load is difficult to be summarized by using a uniform expression. And the aerodynamic damping of the wire when wind vibration occurs is increased along with the increase of the average wind speed, the resonance component of the wind vibration response is greatly reduced due to the aerodynamic damping, and the wind vibration response can be ignored in the calculation. And the single tower system consisting of the ultra-high and large span towers also needs to consider the correction generated by the tower line coupling effect, which has important significance for finally calculating the wind load of the high-precision single tower system.
Disclosure of Invention
Aiming at the problems, the invention provides a calculation method of the wind load of the ultrahigh and large-span tower and the line based on the inertia force method and the tower line separation method, which considers the tower line coupling influence, so as to improve the wind load calculation accuracy of a tower line system. In order to achieve the purpose, the invention adopts the following specific technical scheme:
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 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; the data at least comprises the roughness class of the ground where the ultra-high large span tower is positioned and the average speed division at the set height of 10m
Figure RE-GDA0002611340760000011
Total height H and heel b of ultrahigh large-span tower1Number of cross arms ncAverage extension length of cross arm
Figure RE-GDA0002611340760000012
And the arrangement scheme of the power transmission tower, the lead and the insulator string; but also wire linearity, wire length, etc. S2: based on tower line coupling influence factors and according to tower equivalent damping coefficients in a tower line systeme(ii) a S3: the equivalent damping coefficient of the pole tower in the tower line system obtained in the step S2eTo 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; s4: the tower line coupling effect is considered, and the wind load pulsation reduction coefficient of a tower line system is obtainedc(ii) a S5: according to the stepsThe wind load pulsation reduction coefficient of the tower line system obtained in the step S4 is corrected and calculated by the wind vibration coefficient of the tower line system ultrahigh large crossing tower and the wind vibration coefficient of the tower line system power transmission line in the step S3, and the corrected wind vibration coefficient beta of the tower line system ultrahigh large crossing tower is obtained*(z) corrected wind vibration coefficient beta of tower line system transmission line*(ii) a S6: based on a tower line separation method, calculating the design wind load f of the ultrahigh power transmission tower in the ultrahigh and large-span tower line system under the action of equivalent vibration inertia forceESWL(z) design wind load W of large span transmission lineX。
In a further technical scheme, the step S2 includes the following steps:
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 lcaInsulator length is linThe wire span is L. The hanging point of the wire has no height difference. 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 assumed conditions of the vibration of the lead and the insulator string are as follows: the wires on the windward side and the leeward side vibrate synchronously under wind load; the frequency and damping ratio of the insulator string are controlled by the wire, consistent with that of the wire. The generalized mass calculation formula of the windward side and windward side wires is as follows:
Figure RE-GDA0002611340760000021
the calculation formula of the generalized stiffness of the wires on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000022
the generalized damping calculation formula of the wires on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000023
mcthe mass of a unit wire length of a single wire; single wire vibration mode
Figure RE-GDA0002611340760000024
-L≤y≤L；γgThe 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,
Figure RE-GDA0002611340760000025
ζc＝ζsc+ζac；ζscthe damping ratio of the wire structure is adopted; zetaacStarting a damping ratio for the wire; n is a radical ofcThe number of the split conductors; t iswThe horizontal tension of a single wire in an average wind state; zetacIs the wire damping ratio; the generalized mass calculation formula of the insulator string on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000026
the calculation formula of the generalized rigidity of the insulator strings on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000027
the generalized damping calculation formula of the insulator string on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000028
wherein m isinThe insulator string has unit height mass; dinThe insulator string is windward outer diameter; insulator string vibration mode
Figure RE-GDA0002611340760000029
H-lin≤z≤H；ζinThe damping ratio of the insulator string is;
Figure RE-GDA00026113407600000210
linis 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:
Figure RE-GDA00026113407600000211
in the present invention, the subscript ci represents a cord structure.
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; the calculation formula of the mean square value of the downwind displacement resonance component of the tower under the tower line system is as follows:
Figure RE-GDA0002611340760000031
Figure RE-GDA0002611340760000032
λn＝nci/nt；
Figure RE-GDA0002611340760000033
Figure RE-GDA0002611340760000034
1-order mode vibration mode phi of towert(z)＝(z/H)2，0≤z≤H；
Figure RE-GDA0002611340760000035
In order to obtain the generalized mass of the tower,
Figure RE-GDA0002611340760000036
Mcamass of cross arm, mt(z) the mass per unit height of the tower which varies with the height; coh (z)1,z2) Is z1And z2A coherence function of the pulsating wind speed at two points at height; sf(nt) To normalize the wind velocity spectrum, ntThe frequency of the tower pulsating wind speed is shown;
Figure RE-GDA0002611340760000037
σv'is the standard deviation of the pulsating wind speed;
Figure RE-GDA0002611340760000038
is the generalized mass ratio of the cable structure to the tower,
Figure RE-GDA0002611340760000039
λnthe frequency ratio of the cable structure to the tower is obtained; lambda [ alpha ]n＝nci/nt(ii) a The conducting wire is hung on the top of the tower,
Figure RE-GDA00026113407600000310
ζtis the total damping ratio; zetat＝ζst+ζat；ζstThe damping ratio of the tower structure is set; omegatThe 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≈ζc，ζc＝ζsc+ζac；
ρais the density of air, mus(z) is the coefficient of variation of wind pressure with height; bs(z) the windward width as a function of height;
Figure RE-GDA00026113407600000311
mean wind speed, σ, as a function of altitudev'Is the standard deviation of the pulsating wind speed;
ζatthe pneumatic damping ratio of the tower is;
Figure RE-GDA00026113407600000312
As,cathe wind shielding area of the cross arm; of downwind displacement resonance component of tower during single towerThe mean square value is:
Figure RE-GDA00026113407600000313
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:
Figure RE-GDA00026113407600000314
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. The steps of calculating the formula are: the equivalent damping ratio of the tower after the wire is hung is as follows:
Figure RE-GDA0002611340760000041
where ρ and ζeThe relationship of (1) is:
Figure RE-GDA0002611340760000042
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 λnThe 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
Figure RE-GDA0002611340760000043
An item; the conducting wire is hung on the top of the tower,
Figure RE-GDA0002611340760000044
therefore, the calculation formula of the tower line equivalent damping coefficient after the wire is suspended is as follows:
Figure RE-GDA0002611340760000045
in a further technical scheme, step S3 is carried out to obtain wind vibration coefficient beta (z) of the tower line system ultrahigh large span towerThe method comprises the following steps: 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
Figure RE-GDA0002611340760000046
The total height H of the ultrahigh large span tower; heel lift b1(ii) a Number of crossarms nc(ii) a Average overhang length of cross arm
Figure RE-GDA0002611340760000047
The self-supporting power transmission tower is divided into a transverse partition surface, a cross arm and a residual tower body 3 part; the cross partition surfaces, the cross arms and the residual tower bodies have different distribution rules of the mass and the wind shielding area along the height, and need to be treated differently in the calculation process. 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)；
Figure RE-GDA0002611340760000048
z is the actual height value. The bending mode has the following integral relationship:
Figure RE-GDA0002611340760000049
s313: introducing a background component factor B according to a load specificationz(z) and further calculating a correlation coefficient rho of the fluctuating wind load of the ultrahigh power transmission tower in the horizontal directionx(ii) a Comparing the height of the ultrahigh power transmission tower with the height of gradient wind, and calculating the correlation coefficient rho of the fluctuating wind load in the vertical directionz(ii) a Introducing and calculating a resonance component factor R according to a load specification; determining a ground roughness index alpha; crest factor gs(ii) a Turbulence I at a height of 10m10；
Figure RE-GDA00026113407600000410
Hg is the gradient wind height; xi1＝e；
Figure RE-GDA00026113407600000411
n is the frequency of the pulsating wind speed;
s314: obtaining fitting coefficient k of intermediate variable gamma of background component factorγ、aγ、lγ、mγAnd bγ(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 changev(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 thetalThe correction coefficient thetalCorrection factor theta for wind vibration coefficient taking into account additional areaaCorrection factor theta for wind vibration factor taking into account additional massmThe 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 changeb(z) correction factor theta for cross arm wind vibration coefficient considering local shape changeb(zI) Correction factor theta considering local shape change with wind vibration coefficient of diaphragmb(zJ)；
Figure RE-GDA0002611340760000051
Figure RE-GDA0002611340760000052
S316: according to the actual height value z of the tower body, correspondingly solving a background component factor Bz (z) at the height z according to the correction coefficient obtained in the step S315;
Figure RE-GDA0002611340760000053
μzgthe 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:
Figure RE-GDA0002611340760000054
gsis a peak value factor which is taken according to the load specification.
The calculation model of the design wind vibration coefficient of the power transmission tower is gradually perfected by dividing the power transmission tower into a residual tower body, a cross partition surface and a cross arm 3 part and respectively considering the influence of the 3 parts. The purpose of simplifying calculation is achieved by carrying out nonlinear fitting on the complex multiple integral function and establishing a simplified model of the space distribution relation among the residual tower bodies, the cross arms and the cross partition surfaces. The correction coefficient theta is obtained by taking the gradient wind height factor of the ultrahigh power transmission tower and the concrete in the steel pipe as additional quality factorsb、θlAnd thetaηAnd a wind vibration coefficient design formula of the power transmission tower with the cantilever cross arm is deduced. The calculation steps are simple and the final design effect is good.
According to a further technical scheme, the wind vibration coefficient of the maximum wind deflection angle of the tower line system suspension insulator string is beta; 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; the physical parameters of the lead at least comprise the type of the lead, the calculated sectional area of the lead, the elastic modulus of the lead, the linear density and the outer diameter of the lead; and the physical parameters of the insulator string on the power transmission tower at least comprise the length of the insulator string, the elastic modulus of the insulator string, the quality of the insulator string and the wind shielding area of the insulator string.
When the model for calculating the wind deflection angle of the suspension insulator string is used, a connecting point A of a lead and the insulator string, a tail end point B of the suspension insulator string, a tail end point movement point B ' of the insulator string in a dynamic state and a wind deflection angle caused by the fact that a point B ' moves to a point B ' in the dynamic state are set
Figure RE-GDA0002611340760000055
Downwind displacement of point B under action of wire span L and average wind load
Figure RE-GDA0002611340760000056
A、BLength l of insulator chain between two pointsABThe hanging point difference h between two ends of the wire and the average wind deflection angle
Figure RE-GDA0002611340760000057
The horizontal distance a 'from the origin of coordinates 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 is in a catenary configuration under a self-weight state, and shows large geometric deformation under the action of wind load. Previous researches show that the influence of the power transmission tower on the wind vibration response of the wire is small. In order to simplify the calculation, the influence of the tower is ignored, and the hanging point of the insulator on the tower is taken as a fixed hinged support, so that the wind deflection angle research is carried out on the hanging wire suspension insulator string.
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 towersESWLThe calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000061
wherein (: i) represents the ith column element of the matrix;
Figure RE-GDA0002611340760000062
equivalent background wind pressure;
Figure RE-GDA0002611340760000063
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:
Figure RE-GDA0002611340760000064
in the formula,
Figure RE-GDA0002611340760000065
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;
Figure RE-GDA0002611340760000066
the displacement of the lead joint along the wind direction under the action of average wind load. The lead is of a light flexible structureThe expression under strong wind load is as follows: 1) the structure is greatly deformed, and the geometric nonlinearity is obvious; 2) the structure stress and the displacement do not have a linear relation; 3) under the action of dynamic load, the structure is time-varying rigidity. Therefore, the above equation is a variable coefficient differential equation, and cannot be solved by using the linear superposition principle. The wind vibration response of the wire caused by the incoming wind load can be decomposed into an average response and a pulse response.
M is a quality matrix; c is a damping matrix; a K stiffness matrix; l issIs 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:
Figure RE-GDA0002611340760000067
according to the scheme, an LRC method is adopted to achieve equivalent static wind load. The wire is a light flexible structure, and the performance under the strong wind load is as follows: 1) The structure is greatly deformed, and the geometric nonlinearity is obvious; 2) the structure stress and the displacement do not have a linear relation; 3) under the action of dynamic load, the structure is time-varying rigidity.
Therefore, the vibration equation matrix expression of the wire under the action of the pulsating wind load can be obtained by taking the average wind state of the wire as the initial calculation condition.
The vibration equation matrix expression of the lead under the action of wind load cannot be solved by adopting a linear superposition principle. The wind vibration response of the wire caused by the incoming wind load can be decomposed into an average response and a pulse response.
According to the content, the maximum wind deflection angle of the suspension insulator string can be calculated according to the equivalent static wind load; the calculation formula for calculating the maximum wind drift angle of the suspension insulator string by the equivalent static wind load is as follows:
Figure RE-GDA0002611340760000068
in the formula,
Figure RE-GDA0002611340760000069
the downwind peak displacement of the point B under the action of fluctuating wind load; lABA, B is the length of the insulator string between two points;
Figure RE-GDA00026113407600000610
is the downwind displacement of the point B under the action of average wind load,
Figure RE-GDA00026113407600000611
is the average wind deflection angle; the specific calculation formula is as follows:
Figure RE-GDA00026113407600000612
Figure RE-GDA00026113407600000613
Gvrespectively taking the average wind load and the vertical gravity load of the suspension insulator string at the target point;
Figure RE-GDA00026113407600000614
Wvrespectively the average wind load and the vertical load transferred 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
Figure RE-GDA00026113407600000615
The calculation formula of (2) is as follows:
Figure RE-GDA00026113407600000616
Figure RE-GDA00026113407600000617
in the formula, NcThe number of the split conductors;
Figure RE-GDA00026113407600000618
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
Figure RE-GDA00026113407600000619
Performing curve integration at a horizontal span; wherein,
Figure RE-GDA00026113407600000620
in the formula,
Figure RE-GDA0002611340760000071
is the load p' and the response yBThe correlation coefficient of (a);
Figure RE-GDA0002611340760000072
is a response y in the initial conditionBThe 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 stringvThe calculation formula of (2) is as follows: wv＝Pv l+Tvl+Pv r+Tvr；
Wherein,l、rrespectively calculating the lengths of the left span and the right span of the target point; t isvl、TvrThe 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:
Figure RE-GDA0002611340760000073
T vl0; when the slope of the wire at the geometrical line within the span is not 0:
Figure RE-GDA0002611340760000074
in the formula, TwThe calculation formula is the horizontal tension of a single wire in an average wind state: t isw＝σo4Ac；
Wherein,
Figure RE-GDA0002611340760000075
in the formula, subscripts "3" and "4" represent a no-wind state and an average wind state, respectively; a. thecThe stress area of the lead is defined; ecIs the modulus of elasticity of the wire;γcis the comprehensive specific load of the lead wires,
Figure RE-GDA0002611340760000076
γwin order to obtain the average wind pressure specific load,
Figure RE-GDA0002611340760000077
Figure RE-GDA0002611340760000078
the calculation formula is the average wind load of the unit line length of the lead:
Figure RE-GDA0002611340760000079
lrrepresents a span; beta is arTo represent a height difference angle
S323: calculating the wind vibration coefficient beta of the maximum wind deflection angle of the suspension insulator string of the tower wire system;
Figure RE-GDA00026113407600000710
∑Crepresenting summing elements within a computational domain;ccalculating the line length of the wire in the domain;
Figure RE-GDA00026113407600000711
the average wind load is obtained;
Figure RE-GDA00026113407600000712
equivalent background wind pressure.
The further technical scheme is as follows: wind load pulsation reduction coefficient of tower-line systemcThe 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 Hut(H) A relation with tower wind vibration coefficient beta (H);
Figure RE-GDA00026113407600000713
wherein, ω is0The basic wind pressure is obtained; mu.sz(H) The coefficient of variation of wind pressure along with the height of the super-high large spanning tower is shown; mu.ss(H) The resistance coefficient of the tower along with the height is obtained; bs(H) Windward width that varies with height; gsIs 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;
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 obtaineduc(H) The calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000081
wherein, N ispThe number of phases of the wire; mu.sscIs the wire resistance coefficient; n is a radical ofcThe number of the split conductors; dcCalculating the outer diameter of the sub-conductor/ground wire; l ispIs a horizontal span; h is the height of the tower; etIs 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;
Figure RE-GDA0002611340760000082
wherein, the
Figure RE-GDA0002611340760000083
Responding to the tower caused by the average wind load of the tower;
Figure RE-GDA0002611340760000084
responding to the tower caused by the average wind load of the lead;
Figure RE-GDA0002611340760000085
caused by the mean wind load of the tower line systemTower response sigmarThe standard deviation of the tower response under the tower wire system; gsIs the crest factor; sigmartThe root-mean-square response of the tower body caused by the fluctuating wind load of the tower; sigmarcThe 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:
Figure RE-GDA0002611340760000086
Figure RE-GDA0002611340760000087
represents the peak response caused by the tower load,
Figure RE-GDA0002611340760000088
representing the peak response caused by the transmission line load. Introduction ofcThen, the maximum response of the tower can be determined by linear superposition after the maximum response of the tower is reduced due to the two parts of loads. If not taken into considerationc，
Figure RE-GDA0002611340760000089
Represents the peak response caused by the tower load,
Figure RE-GDA00026113407600000810
the peak response caused by the power line load is shown, and the result of the linear superposition is larger than the actual value.
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:
Figure RE-GDA00026113407600000811
σucthe root mean square value of the displacement of the tower top caused by the load of the lead is represented; sigmaut(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;
Figure RE-GDA00026113407600000812
wherein,
Figure RE-GDA00026113407600000813
the tower wind load fluctuation reduction coefficient calculation method considering the tower line coupling effect is suitable for the expression of the tower wind load fluctuation reduction coefficient of the ultrahigh power transmission tower. Therefore, the power transmission tower wind load design method which considers the tower-line coupling influence by adopting the tower wind load pulsation reduction coefficient is provided.
In a further technical scheme, the tower line system is ultrahigh and spans the corrected wind vibration coefficient beta of the tower*(z) and corrected wind vibration coefficient beta of said tower wire system transmission line*The calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000091
according to a further technical scheme, the design wind load f of the ultrahigh power transmission tower in the line system of the ultrahigh large-span tower is calculated under the action of equivalent vibration inertia forceESWL(z) and corrected wind vibration coefficient beta*(z) is given by:
Figure RE-GDA0002611340760000092
wherein ξ1＝ξe；
Figure RE-GDA0002611340760000093
Figure RE-GDA0002611340760000094
Figure RE-GDA0002611340760000095
m(z)＝m(0)μm(z)；
Figure RE-GDA00026113407600000912
Sf(n)Sf(n) is a normalized wind speed spectrum,
Figure RE-GDA0002611340760000097
Iz(z) is the pulsating wind turbulence density at z-height;
Figure RE-GDA0002611340760000098
Figure RE-GDA0002611340760000099
I10a pulsating wind turbulence density at a height of 10 m; x'1Is a formula of
Figure RE-GDA00026113407600000910
Where n is n1Value of time, n11 order modal frequency of the power transmission tower; u. of1And ηxz1The 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.
In a further technical scheme, the design wind load W of the transmission line is calculated based on a tower-line separation methodXThe calculation formula of (2) is as follows:
Figure RE-GDA00026113407600000911
wherein β ═ α' βc(ii) a Wherein α' is a radicalThe value is less than 1; mu.sscIs the wire resistance coefficient; beta is acTaking 1 when calculating the wind deflection angle for adjusting the coefficient of the wind load; dc is the calculated outer diameter of the sub-conductor/ground wire; lp is the horizontal span of the tower; b is1The coefficient is the increase coefficient of wind load during ice coating; omega0The basic wind pressure is obtained; mu.szThe coefficient of variation of wind pressure along with height is shown; b islThe coefficient is the increase coefficient of wind load during ice coating; n is a radical ofcThe number of the split conductors; theta is a wind direction angle.
The invention has the beneficial effects that: and calculating the designed wind load of the ultrahigh large-span tower in the tower line system by adopting an equivalent vibration inertia force method, carrying out refined calculation on the damping coefficient and considering the correction condition generated by the tower line coupling effect. The design wind load of the tower-line system transmission line is calculated by a tower-line separation method, considering the damping coefficient for fine calculation and considering the correction condition generated by the tower-line coupling effect, so that the finally designed tower-line system is closer to the reality and has high design precision.
Drawings
FIG. 1 is a diagram of a tower line system calculation model;
FIG. 2 is a diagram of the mode shapes of the wire and the insulator string;
FIG. 3: a tower line coupling simplified calculation model diagram;
FIG. 4 is a calculation chart of an ultra-high large spanning tower;
FIG. 5 is a schematic view of a wind deflection angle calculation model of a suspension insulator string;
FIG. 6 is a flow chart of the present invention calculation;
FIG. 7 is a flow chart of tower equivalent damping coefficient calculation in a tower-line system;
FIG. 8 is a flow chart of wind vibration coefficient calculation for a tower line system super-high spanning tower;
FIG. 9 is a flow chart of the wind vibration coefficient calculation for the maximum wind drift angle of the tower-line system suspension insulator string;
FIG. 10 is a flow chart of tower-line system wind load pulsation reduction coefficient calculation;
fig. 11 is a diagram for defining a wind direction angle.
Detailed Description
The following provides a more detailed description of the embodiments and the operation of the present invention with reference to the accompanying drawings.
A calculation method for line wind load and ultra-high large-span tower based on the inertia force method and the tower line separation method considering the tower line coupling influence can be seen by combining figure 6, and 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; the tower line system of the ultra-high large-span tower can be seen by combining the figure 1.
S2: based on tower line coupling influence factors and according to tower equivalent damping coefficients in a tower line systeme(ii) a Specifically, as can be seen from fig. 7, the specific steps of step S2 are: s21: and obtaining a calculation model diagram of the line system of the ultra-high large-span tower according to the line system of the ultra-high large-span tower in the step S1, which is detailed in FIG. 2. 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 lcaInsulator length is linThe wire span is L; the hanging point of the wire has no height difference. 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 wires on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000101
the calculation formula of the generalized stiffness of the wires on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000102
the generalized damping calculation formula of the wires on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000103
mcthe mass of a unit wire length of a single wire; single wire vibration mode
Figure RE-GDA0002611340760000104
γgThe 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,
Figure RE-GDA0002611340760000111
ζc＝ζsc+ζac；ζscthe damping ratio of the wire structure is adopted; zetaacStarting a damping ratio for the wire; n is a radical ofcThe number of the split conductors; t iswThe horizontal tension of a single wire in an average wind state; zetacIs the wire damping ratio;
the generalized mass calculation formula of the insulator string on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000112
the calculation formula of the generalized rigidity of the insulator strings on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000113
the generalized damping calculation formula of the insulator string on the windward side and the windward side is as follows:
Figure RE-GDA0002611340760000114
wherein m isinThe insulator string has unit height mass; dinThe insulator string is windward outer diameter; insulator string vibration mode
Figure RE-GDA0002611340760000115
H-lin≤z≤H；ζinThe damping ratio of the insulator string is;
Figure RE-GDA0002611340760000116
linis the length of the insulator; wherein, the generalized mass, the generalized rigidity and the generalized damping corresponding to the cable structure systemThe calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000117
s23: combining the data construction cable structure system obtained in the step S22 with the tower structure to form a tower-line coupling simplified calculation model, which is detailed in fig. 3 in this embodiment; 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; 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:
Figure RE-GDA0002611340760000118
the mean square value of the downwind displacement resonance component of the tower in the single tower is as follows:
Figure RE-GDA0002611340760000119
Figure RE-GDA00026113407600001110
the calculation formula of the mean square value of the downwind displacement resonance component of the tower under the tower line system is as follows:
Figure RE-GDA00026113407600001111
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.
The calculation formula of the equivalent damping coefficient of the tower in the tower wire system is as follows:
Figure RE-GDA00026113407600001112
for a transmission tower wire system, the cable structure is a flexible system, and the excellent frequency is far less than that of a tower. Therefore, λ can be ignored in equation (1)nThe higher order terms of (1). In addition, the damping ratio of the tower is about 0.01, and the damping ratio of the cable structure is less than 1 and can be ignored
Figure RE-GDA0002611340760000121
An item. For the computational model of fig. 3, the wires are suspended from the top of the tower,
Figure RE-GDA0002611340760000122
at this time, equation (1) can be simplified as:
Figure RE-GDA0002611340760000129
s3: referring to fig. 8, it can be seen that the equivalent damping coefficient of the tower in the tower line system obtained in step S2 is usedeTo replace the damping coefficient ζ1Solving the wind vibration coefficient beta (z) of the tower line system ultrahigh large span tower; in the present embodiment, as can be seen from fig. 4, the calculation map is an ultrahigh large-span tower calculation map; the method comprises the following specific steps: 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
Figure RE-GDA0002611340760000123
The total height H of the ultrahigh large span tower; heel lift b1(ii) a Number of crossarms nc(ii) a Average overhang length of cross arm
Figure RE-GDA0002611340760000124
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)；
Figure RE-GDA0002611340760000125
z is the actual height value
S313: introducing a background component factor B according to a load specificationz(z) and further calculating a correlation coefficient rho of the fluctuating wind load of the ultrahigh power transmission tower in the horizontal directionx(ii) a Comparing the height of the ultrahigh power transmission tower with the height of gradient wind, and calculating the correlation coefficient rho of the fluctuating wind load in the vertical directionz(ii) a Introducing and calculating a resonance component factor R according to a load specification; determining a ground roughness index alpha; crest factor gs(ii) a Turbulence I at a height of 10m10；
Figure RE-GDA0002611340760000126
Hg is the gradient wind height; xi1＝e；
Figure RE-GDA0002611340760000127
n is the frequency of the pulsating wind speed;
s314: obtaining fitting coefficient k of intermediate variable gamma of background component factorγ、aγ、lγ、mγAnd bγ(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 changev(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 thetalThe correction coefficient thetalCorrection factor theta for wind vibration coefficient taking into account additional areaaCorrection factor theta for wind vibration factor taking into account additional massmThe product of (a); in this example, fitting coefficient k is obtained in combination with Table 1γ、aγThe value of (a). In combination with Table 2, m can be obtainedγAnd bγThe value of (a).
TABLE 1 kγAnd aγValue of
Figure RE-GDA0002611340760000128
Figure RE-GDA0002611340760000131
TABLE 2 lγ、mγAnd bγValue of
Class of roughness of ground A B C D
lγ 3.208 2.818 2.030 1.360
mγ -3.346 -2.909 -2.067 -1.374
bγ 229.182 253.879 299.306 341.215
Considering the effect of gradient wind height but not the concrete quality effect, θvThe expression of (a) is:
Figure RE-GDA0002611340760000132
take e 10 as the basis of tabulation, theta is listedvTable, see Table 3
TABLE 3 Theta when the width and depth of the ultra-high transmission tower are changed along the height with the same rulevValue of (A)
Figure RE-GDA0002611340760000133
The correction coefficient thetalCorrection factor theta for wind vibration coefficient taking into account additional areaaCorrection factor theta for wind vibration factor taking into account additional massmThe specific values of the product are shown in table 4, and the calculation formula is as follows:
Figure RE-GDA0002611340760000134
Figure RE-GDA0002611340760000135
TABLE 4 theta of ultra-high transmission towerslValue taking
Figure RE-GDA0002611340760000141
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 changeb(z) correction factor theta for cross arm wind vibration coefficient considering local shape changeb(zI) Correction factor theta considering local shape change with wind vibration coefficient of diaphragmb(zJ)；
Figure RE-GDA0002611340760000142
Figure RE-GDA0002611340760000143
S316: according to the actual height value z of the tower body, correspondingly solving a background component factor Bz (z) at the height z according to the correction coefficient obtained in the step S315;
Figure RE-GDA0002611340760000144
μzgthe 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:
Figure RE-GDA0002611340760000145
in this embodiment, as can be seen from fig. 9, the steps of the wind vibration coefficient β of the maximum wind deflection angle of the tower-line system suspension insulator string are as follows:
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 towersESWLThe calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000146
wherein (: i) represents the ith column element of the matrix;
Figure RE-GDA0002611340760000147
equivalent background wind pressure;
Figure RE-GDA0002611340760000148
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:
Figure RE-GDA0002611340760000149
in the formula,
Figure RE-GDA00026113407600001410
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;
Figure RE-GDA00026113407600001411
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 issIs 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:
Figure RE-GDA0002611340760000151
the calculation formula for calculating the maximum wind drift angle of the suspension insulator string by the equivalent static wind load is as follows:
Figure RE-GDA0002611340760000152
in the formula,
Figure RE-GDA0002611340760000153
is the downwind peak displacement of the point B under the action of fluctuating wind load
Figure RE-GDA0002611340760000154
lABA, B is the length of the insulator string between two points;
Figure RE-GDA0002611340760000155
Figure RE-GDA0002611340760000156
is the downwind displacement of the point B under the action of average wind load,
Figure RE-GDA0002611340760000157
Figure RE-GDA0002611340760000158
is the average wind deflection angle; the specific calculation formula is as follows:
Figure RE-GDA0002611340760000159
Figure RE-GDA00026113407600001510
Gvrespectively taking the average wind load and the vertical gravity load of the suspension insulator string at the target point;
Figure RE-GDA00026113407600001511
Wvrespectively 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
Figure RE-GDA00026113407600001512
The calculation formula of (2) is as follows:
Figure RE-GDA00026113407600001513
Figure RE-GDA00026113407600001514
in the formula, Nc is the number of the split conductors;
Figure RE-GDA00026113407600001515
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
Figure RE-GDA00026113407600001516
Performing curve integration at a horizontal span; wherein,
Figure RE-GDA00026113407600001517
in the formula,
Figure RE-GDA00026113407600001518
is the load p' and the response yBThe correlation coefficient of (a);
Figure RE-GDA00026113407600001519
is a response y in the initial conditionBThe 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 stringvThe calculation formula of (2) is as follows: wv＝Pv l+Tvl+Pv r+Tvr；
Wherein,l、rrespectively calculating the lengths of the left span and the right span of the target point; t isvl、TvrThe 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:
Figure RE-GDA00026113407600001520
T vl0; when the slope of the wire at the geometrical line within the span is not 0:
Figure RE-GDA00026113407600001521
in the formula, TwThe calculation formula is the horizontal tension of a single wire in an average wind state: t isw＝σo4Ac；
Wherein,
Figure RE-GDA00026113407600001522
in the formula, subscripts "3" and "4" represent a no-wind state and an average wind state, respectively; a. thecThe stress area of the lead is defined; ecIs the modulus of elasticity of the wire; gamma raycIs the comprehensive specific load of the lead wires,
Figure RE-GDA00026113407600001523
γwin order to obtain the average wind pressure specific load,
Figure RE-GDA0002611340760000161
Figure RE-GDA0002611340760000162
the calculation formula is the average wind load of the unit line length of the lead:
Figure RE-GDA0002611340760000163
lrrepresents a span; beta is arIs representative of a height difference angle;
s323: calculating the wind vibration coefficient of the suspension insulator string;
Figure RE-GDA0002611340760000164
∑Crepresenting summing elements within a computational domain;ccalculating the line length of the wire in the domain;
Figure RE-GDA0002611340760000165
the average wind load is obtained;
Figure RE-GDA0002611340760000166
equivalent background wind pressure.
In this embodiment, a calculation formula for calculating the wind vibration coefficient β of the tower line system power transmission line is shown as follows;
Figure RE-GDA0002611340760000167
Figure RE-GDA0002611340760000168
∑Crepresenting summing elements within a computational domain;ccalculating the line length of the wire in the domain;
Figure RE-GDA0002611340760000169
the average wind load is obtained;
Figure RE-GDA00026113407600001610
equivalent background wind pressure.
In this embodiment, the standard value expression of the horizontal wind load of the lead/ground wire of DL/T5154 is as follows:
Figure RE-GDA00026113407600001611
wherein β ═ α' βc；
In the formula, alpha' is a wind pressure uneven coefficient with the value less than 1; mu.sscIs a coefficient of resistance; beta is acTaking 1 when calculating the wind deflection angle for adjusting the coefficient of the wind load; dcCalculating the outer diameter of the sub-conductor/ground wire; l ispThe horizontal span of the tower; b islThe coefficient of increase of wind load during ice coating. Omega0The basic wind pressure is obtained; mu.szThe coefficient of variation of wind pressure along with height is shown; b islThe coefficient is the increase coefficient of wind load during ice coating; n is a radical ofcThe number of the split conductors; theta is a wind direction angle.
In the present invention, as defined in connection with fig. 11, the wind direction angle θ is 0 ° when the incoming wind is parallel to the cross arm axial direction, and 90 ° when the incoming wind runs parallel to the wire. Wherein, the x direction represents the axial direction of the cross arm, and the y direction represents the forward direction.
The wind vibration coefficient has little change along with the wind direction angle, and the wind direction angle has opposite influences on the wind vibration coefficient of the tower body and the wind vibration coefficient of the cross arm, and the influences can be counteracted for the whole tower. The wind vibration coefficient of the transmission tower at the wind direction angle of 0 degrees is only considered in the electric power related standard. Therefore, the influence of wind direction angles 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/T5154.
Wherein the power-related criteria include: GB 50545-2010.110 kV-750 kV overhead transmission line design Specification [ S ]. Beijing, China plan Press, 2010; GB 50665-2011.1000kV overhead transmission line design Specification [ S ]. Beijing, Chinese Schedule Press, 2011; DL/T5154 + 2012. design technical specification of tower structure of overhead transmission line [ S ]. Beijing, China plan Press, 2012; DL/T5504-2015, ultra-high voltage overhead transmission line large span design technical regulation [ S ]. Beijing, China plan Press, 2015.
α′βcThe physical significance of the beta in the load specification is consistent, and the pulsating wind power effect is considered. Average wind load multiplied by beta by considering wind pressure non-uniformitycAnd determining the equivalent static wind load of the lead/ground wire. Thus, α' βcβ. According to the physical meaning of the composition,
Figure RE-GDA0002611340760000171
beta calculated by LRC is not constant, and for convenient design and use, is based on pESWLThe distribution characteristics of (a) are processed in an averaging manner to calculate the uniform beta. p is a radical ofESWLConvex at the target point position and close to the target point position far away
Figure RE-GDA0002611340760000172
Is non-uniformly distributed. Therefore, a calculation domain is set, and the equivalent static wind load of the target point is averaged in the calculation domain. And when the height difference between the target point and the adjacent tower wire hanging point is 0, selecting the target point horizontal span as the calculation domain. When the height difference exists, the equivalent static wind load at the position of the target point is more convex, so that the calculation domain is spanned by the left and right sides 1/4 of the selected target point.
S4: the tower line coupling effect is considered, and the wind load pulsation reduction coefficient of a tower line system is obtainedcAs can be seen from fig. 10, the following are specific: s41: constructing a calculation model of the super-high spanning tower line system, and obtaining a calculation model diagram of the tower line system as detailed shown in FIG. 1; the tower in the tower line system calculation model is of a compact structure, and the tower body is squareThe variable cross section 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 lcaInsulator length is linThe wire span is L. The hanging point of the wire has no height difference;
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 Hut(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 obtaineduc(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 Hut(H) The relation between the tower wind vibration coefficient beta (H) is as follows:
Figure RE-GDA0002611340760000173
wherein, ω is0The basic wind pressure is obtained; mu.sz(H) The coefficient of variation of wind pressure along with the height of the ultrahigh single tower is shown; mu.ss(H) The resistance coefficient of the tower along with the height is obtained; bs(H) Windward width that varies with height; gsIs 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 loaduc(H) The calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000174
wherein N ispThe number of phases of the wire; mu.sscIs the wire resistance coefficient; n is a radical ofcThe number of the split conductors; dcCalculating the outer diameter of the sub-conductor/ground wire; l ispIs a horizontal span; h is the height of the tower; etIs 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;
Figure RE-GDA0002611340760000181
wherein, the
Figure RE-GDA0002611340760000182
Responding to the tower caused by the average wind load of the tower;
Figure RE-GDA0002611340760000183
responding to the tower caused by the average wind load of the lead;
Figure RE-GDA0002611340760000184
response sigma of tower caused by mean wind load of tower line systemrThe standard deviation of the tower response under the tower wire system; gsIs the crest factor; sigmartThe root-mean-square response of the tower body caused by the fluctuating wind load of the tower; sigmarcThe root-mean-square response of the tower body caused by the fluctuating wind load of the lead;
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:
Figure RE-GDA0002611340760000185
Figure RE-GDA0002611340760000186
Figure RE-GDA0002611340760000187
represents the peak response caused by the tower load,
Figure RE-GDA0002611340760000188
representing the load of a transmission lineInduced peak response
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:
Figure RE-GDA0002611340760000189
σucthe root mean square value of the displacement of the tower top caused by the load of the lead is represented; sigmaut(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;
Figure RE-GDA00026113407600001810
wherein,
Figure RE-GDA00026113407600001811
in this embodiment, the tower line system has a modified wind vibration coefficient β of the very high spanning tower*(z) and corrected wind vibration coefficient beta of said tower wire system transmission line*The calculation formula of (2) is as follows:
Figure RE-GDA00026113407600001812
designed wind load f of ultrahigh power transmission tower in ultrahigh large-span tower line system calculated under action of equivalent vibration inertia forceESWL(z) and corrected wind vibration coefficient beta*(z) the relationship:
Figure RE-GDA00026113407600001813
wherein ξ1＝ξe；
Figure RE-GDA00026113407600001814
Figure RE-GDA0002611340760000191
Figure RE-GDA0002611340760000192
m(z)＝m(0)μm(z)；
Figure RE-GDA0002611340760000193
Sf(n) is a normalized wind speed spectrum,
Figure RE-GDA0002611340760000194
Iz(z)Iz(z) is the pulsating wind turbulence density at z-height;
Figure RE-GDA0002611340760000195
I10a pulsating wind turbulence density at a height of 10 m; x'1Is a formula of
Figure RE-GDA0002611340760000196
Where n is n1Value of time, n11 order modal frequency of the power transmission tower;
u1and ηxz1The 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.
In the embodiment, the design wind load W of the transmission line is calculated based on the tower line separation methodXThe calculation formula of (2) is as follows:
Figure RE-GDA0002611340760000197
wherein β ═ α' βc(ii) a Alpha' is the uneven coefficient of wind pressure with the value less than 1; mu.sscIs the wire resistance coefficient; beta is acTaking 1 when calculating the wind deflection angle for adjusting the coefficient of the wind load; dcCalculating the outer diameter of the sub-conductor/ground wire; l ispThe horizontal span of the tower; b islThe coefficient is the increase coefficient of wind load during ice coating; omega0The basic wind pressure is obtained; mu.szThe coefficient of variation of wind pressure along with height is shown; b islThe coefficient is the increase coefficient of wind load during ice coating; n is a radical ofcThe number of the split conductors; theta is a wind direction angle.
In conclusion, the ultrahigh and large-span tower can be designed by considering the wind load of the ultrahigh and large-span tower and the line design due to the coupling influence of the tower lines based on the inertia force method and the tower line separation method.
It should be noted that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make variations, modifications, additions or substitutions within the spirit and 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 systeme；
S3: the equivalent damping coefficient of the pole tower in the tower line system obtained in the step S2eTo 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
Figure FDA0002433875970000011
The total height H of the ultrahigh large span tower; heel lift b1(ii) a Number of crossarms nc(ii) a Average overhang length of cross arm
Figure FDA0002433875970000012
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)；
Figure FDA0002433875970000013
z is the actual height value
S313: introducing a background component factor B according to a load specificationz(z) and further calculating a correlation coefficient rho of the fluctuating wind load of the ultrahigh power transmission tower in the horizontal directionx(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 directionz(ii) a Introducing and calculating a resonance component factor R according to a load specification; determining a ground roughness index alpha; crest factor gs(ii) a Turbulence I at a height of 10m10；
Figure FDA0002433875970000021
Hg is the gradient wind height; xi1＝e；
Figure FDA0002433875970000022
n is the frequency of the pulsating wind speed;
s314: obtaining intermediate variations of background component factorsFitting coefficient k of quantity gammaγ、aγ、ly、myAnd by(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 changev(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 thetalThe correction coefficient thetalCorrection factor theta for wind vibration coefficient taking into account additional areaaCorrection factor theta for wind vibration factor taking into account additional massmThe 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 changeb(z) correction factor theta for cross arm wind vibration coefficient considering local shape changeb(zI) Correction factor theta considering local shape change with wind vibration coefficient of diaphragmb(zJ)；
Figure FDA0002433875970000023
Figure FDA0002433875970000024
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 S315z(z)；
Figure FDA0002433875970000025
μzgThe 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:
Figure FDA0002433875970000026
gsis 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 obtainedc；
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 forceX。
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 lcaInsulator length is linThe 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:
Figure FDA0002433875970000031
the calculation formula of the generalized stiffness of the wires on the windward side and the windward side is as follows:
Figure FDA0002433875970000032
the generalized damping calculation formula of the wires on the windward side and the windward side is as follows:
Figure FDA0002433875970000041
mcthe mass of a unit wire length of a single wire; single wire vibration mode
Figure FDA0002433875970000048
γgThe 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,
Figure FDA0002433875970000042
ζc＝ζsc+ζac；ζscthe damping ratio of the wire structure is adopted; zetaacStarting a damping ratio for the wire; n is a radical ofcThe number of the split conductors; t iswThe horizontal tension of a single wire in an average wind state; zetacIs the wire damping ratio;
the generalized mass calculation formula of the insulator string on the windward side and the windward side is as follows:
Figure FDA0002433875970000043
the calculation formula of the generalized rigidity of the insulator strings on the windward side and the windward side is as follows:
Figure FDA0002433875970000044
the generalized damping calculation formula of the insulator string on the windward side and the windward side is：
Figure FDA0002433875970000045
Wherein m isinThe insulator string has unit height mass; dinThe insulator string is windward outer diameter; insulator string vibration mode
Figure FDA0002433875970000049
H-lin≤Z≤H；ζinThe damping ratio of the insulator string is;
Figure FDA0002433875970000046
linis 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:
Figure FDA0002433875970000047
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:
Figure FDA0002433875970000051
wherein,
Figure FDA0002433875970000052
Figure FDA0002433875970000053
λn＝nci/nt；
Figure FDA0002433875970000054
Figure FDA0002433875970000055
Figure FDA0002433875970000056
Figure FDA0002433875970000057
1-order mode vibration mode phi of towert(z)＝(z/H)2，0≤z≤H；
Figure FDA0002433875970000059
In order to obtain the generalized mass of the tower,
Figure FDA0002433875970000058
Mcamass of cross arm, mt(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;
Sf(nt) To normalize the wind velocity spectrum, ntThe frequency of the tower pulsating wind speed is shown;
Figure FDA0002433875970000061
σv'is the standard deviation of the pulsating wind speed;
Figure FDA0002433875970000065
is the generalized mass ratio of the cable structure to the tower,
Figure FDA0002433875970000062
λnthe frequency ratio of the cable structure to the tower is obtained; lambda [ alpha ]n＝nci/nt(ii) a The conducting wire is hung on the top of the tower,
Figure FDA0002433875970000066
ζtis the total damping ratio; zetat＝ζst+ζat；ζstThe damping ratio of the tower structure is set; omegatThe 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≈ζc，ζc＝ζsc+ζac；
ρais the density of air, mus(z) is the coefficient of variation of wind pressure with height; bs(z) the windward width as a function of height;
Figure FDA0002433875970000067
mean wind speed, σ, as a function of altitudev'Is the standard deviation of the pulsating wind speed;
ζatthe pneumatic damping ratio of the tower is;
Figure FDA0002433875970000068
As，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:
Figure FDA0002433875970000063
Figure FDA0002433875970000064
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:
Figure FDA0002433875970000071
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:
Figure FDA0002433875970000072
where ρ and ζeThe relationship of (1) is:
Figure FDA0002433875970000073
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 λnThe 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
Figure FDA0002433875970000075
An item;
the conductor is suspended on the top of the tower，
Figure FDA0002433875970000074
Therefore, the calculation formula of the tower line equivalent damping coefficient after the wire is suspended is as follows:e≈t+μM*λn 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 towersESWLThe calculation formula of (2) is as follows:
Figure FDA0002433875970000081
wherein (: i) represents the ith column element of the matrix;
Figure FDA00024338759700000814
equivalent background wind pressure;
Figure FDA0002433875970000082
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:
Figure FDA0002433875970000083
in the formula,
Figure FDA0002433875970000084
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;
Figure FDA0002433875970000085
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 issIs 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:
Figure FDA0002433875970000086
the calculation formula for calculating the maximum wind drift angle of the suspension insulator string by the equivalent static wind load is as follows:
Figure FDA0002433875970000087
in the formula,
Figure FDA00024338759700000816
is the downwind peak displacement of the point B under the action of fluctuating wind load
Figure FDA00024338759700000815
lABA, B is the length of the insulator string between two points;
Figure FDA0002433875970000088
Figure FDA00024338759700000817
is the downwind displacement of the point B under the action of average wind load,
Figure FDA0002433875970000089
Figure FDA00024338759700000810
is the average wind deflection angle; the specific calculation formula is as follows:
Figure FDA00024338759700000811
Figure FDA00024338759700000818
Gvrespectively taking the average wind load and the vertical gravity load of the suspension insulator string at the target point;
Figure FDA00024338759700000822
Wvrespectively 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
Figure FDA00024338759700000821
The calculation formula of (2) is as follows:
Figure FDA00024338759700000812
Figure FDA00024338759700000819
in the formula, NcThe number of the split conductors;
Figure FDA00024338759700000820
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
Figure FDA00024338759700000813
Performing curve integration at a horizontal span; wherein,
Figure FDA0002433875970000091
in the formula,
Figure FDA0002433875970000098
is the load p' and the response yBThe correlation coefficient of (a);
Figure FDA0002433875970000099
is a response y in the initial conditionBThe 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 stringvThe calculation formula of (2) is as follows: wv＝Pv l+Tvl+Pv r+Tvr；
Wherein,l、rrespectively calculating the lengths of the left span and the right span of the target point; t isvl、TvrThe 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:
Figure FDA0002433875970000092
Tvl0; when the slope of the wire at the geometrical line within the span is not 0:
Figure FDA0002433875970000093
in the formula, TwThe calculation formula is the horizontal tension of a single wire in an average wind state: t isw＝σo4Ac；
Wherein,
Figure FDA0002433875970000094
in the formula, subscripts "3" and "4" represent a no-wind state and an average wind state, respectively; a. thecThe stress area of the lead is defined; ecIs the modulus of elasticity of the wire; gamma raycIs the comprehensive specific load of the lead wires,
Figure FDA0002433875970000095
γwin order to obtain the average wind pressure specific load,
Figure FDA0002433875970000096
Figure FDA00024338759700000910
the calculation formula is the average wind load of the unit line length of the lead:
Figure FDA0002433875970000097
lrrepresents a span; beta is arIs representative of a height difference angle;
s323: calculating the wind vibration coefficient of the suspension insulator string;
Figure FDA0002433875970000101
Figure FDA0002433875970000102
Figure FDA0002433875970000103
∑crepresenting summing elements within a computational domain;ccalculating the line length of the wire in the domain;
Figure FDA0002433875970000105
the average wind load is obtained;
Figure FDA0002433875970000106
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 systemcThe 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 Hut(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 obtaineduc(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 Hut(H) The relation between the tower wind vibration coefficient beta (H) is as follows:
Figure FDA0002433875970000104
wherein, ω is0The basic wind pressure is obtained; mu.sz(H) The coefficient of variation of wind pressure along with the height of the ultrahigh single tower is shown; mu.ss(H) The resistance coefficient of the tower along with the height is obtained; bs(H) Windward width that varies with height; gsIs 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 loaduc(H) The calculation formula of (2) is as follows:
Figure FDA0002433875970000111
wherein N ispThe number of phases of the wire; mu.sscIs the wire resistance coefficient; n is a radical ofcIs the number of split conductors；DcCalculating the outer diameter of the sub-conductor/ground wire; l ispIs a horizontal span; h is the height of the tower; etIs 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;
Figure FDA0002433875970000112
wherein, the
Figure FDA0002433875970000113
Responding to the tower caused by the average wind load of the tower;
Figure FDA0002433875970000114
responding to the tower caused by the average wind load of the lead;
Figure FDA0002433875970000115
response sigma of tower caused by mean wind load of tower line systemrThe standard deviation of the tower response under the tower wire system; gsIs the crest factor; sigmartThe root-mean-square response of the tower body caused by the fluctuating wind load of the tower; sigmarcThe 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:
Figure FDA0002433875970000116
Figure FDA0002433875970000118
represents the peak response caused by the tower load,
Figure FDA0002433875970000119
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:
Figure FDA0002433875970000117
σucthe root mean square value of the displacement of the tower top caused by the load of the lead is represented; sigmaut(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;
Figure FDA0002433875970000121
wherein,
Figure FDA0002433875970000122
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:
Figure FDA0002433875970000123
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 forceESWL(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 towerESWL(z) and corrected wind vibration coefficient beta*(z) is given by:
Figure FDA0002433875970000124
wherein ξ1＝ξe；
Figure FDA0002433875970000125
Figure FDA0002433875970000126
Figure FDA0002433875970000127
Figure FDA0002433875970000131
m(z)＝m(0)μm(z)；
Figure FDA0002433875970000132
Sf(n) is a normalized wind speed spectrum,
Figure FDA0002433875970000134
Iz(z) is the pulsating wind turbulence density at z-height;
Figure FDA0002433875970000135
I10a pulsating wind turbulence density at a height of 10 m; x'1Is a formula of
Figure FDA0002433875970000136
Where n is n1Value of time, n11 order modal frequency of the power transmission tower;
u1and ηxz1The 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 methodXThe calculation formula of (2) is as follows:
Figure FDA0002433875970000133
wherein β ═ α' βc(ii) a Alpha' is the uneven coefficient of wind pressure with the value less than 1; mu.sscIs the wire resistance coefficient; beta is acTaking 1 when calculating the wind deflection angle for adjusting the coefficient of the wind load; dcCalculating the outer diameter of the sub-conductor/ground wire; l ispThe horizontal span of the tower; b islThe coefficient is the increase coefficient of wind load during ice coating; omega0The basic wind pressure is obtained; mu.szThe coefficient of variation of wind pressure along with height is shown; b islThe coefficient is the increase coefficient of wind load during ice coating; n is a radical ofcThe number of the split conductors; theta is a wind direction angle.
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