CN102623939B - A kind of power transmission line transportation work style calculated based on simulation stochastic matrix wind field is shaken administering method - Google Patents

Abstract

A kind of power transmission line transportation work style calculated based on multidimensional stochastic matrix simulation of wind, iron tower of power transmission line-lead/ground wire integral system model is shaken administering method: first, based on multidimensional random vibration theory, generate wind load time history sample according to harmonic and reactive detection method, wind field is simulated; Secondly, set up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system, to leading/ground wire carries out initial form analysis, arranges the boundary condition of model; 3rd, wind load is converted to blast, power transmission line column wire system is loaded, utilize simulation software to calculate axial stress and the displacement versus time course of steel tower rod member; Finally, analyze and judge that shake intensity and wind of wind shakes inhibition, improve regulation effect by prioritization scheme.The present invention considers that hard and soft Dynamics Coupling, stochastic matrix wind field and shaft tower between electric power line pole tower, wire and ground wire-lead/interstructural fluid structurecoupling of earth system, the wind determined thus shake administering method, have better implementation result.

Description

A kind of power transmission line transportation work style calculated based on simulation stochastic matrix wind field is shaken administering method

Technical field

The present invention relates to a kind of power transmission line transportation work style calculated based on simulation stochastic matrix wind field to shake administering method.

Background technology

Transmission line is the critical piece of delivery of electrical energy in electrical network, and normal, the safe operation of transmission line are the important leverages avoiding electrical network major accident.Shaft tower-lead/ground wire system is as the supporter of transmission line, and what it was made up of wire, insulator and power transmission tower has strong nonlinear complicated couple system.Power transmission tower is a kind of towering flexible structure, more responsive to dynamic loads such as wind loads, easily produces larger dynamic response.The destruction of power transmission tower system can cause the paralysis of electric power system, and this not only seriously affects production and construction, orders of life, and can cause secondary disaster, causes serious consequence to society and people's lives and properties.The wind of world wide transmission line disaster of shaking presents increasing trend in recent years.In China, the destruction situation of power transmission tower system is also very serious, and the thing that power transmission tower is fallen by wind, almost has generation every year.When wind shakes serious, may cause alternate flashover, damage such as gold utensil such as tripping operation powers failure, wire clamp etc., wire strand breakage even shaft tower collapse, be one of disaster of transmission line.

Shake to the destruction of transmission system for wind, also do not have the wind of comparative maturity to shake administering method at present.About scholar expert to shake the research of improvement and draught exclusion device based on shake mechanism, wind of wire wind, successively sum up some wind and to shake administering method.But still there is larger limitation in existing method: (1) does not consider shaft tower-lead/ground wire system and wind and to shake the coupling effect of controlling device; (2) randomness of wind field is not considered.Chinese invention patent " reduces dynamic absorber and the energy-dissipating device of wind vibration response of high tower structure ", and (patent No. CN1840794A) proposes a kind of device carrying out vibration damping control for tower structure (directly for mast structure) vibration; Chinese invention patent " a kind of method for controlling wind vibration of electric transmission line high tower " (patent No. CN101692566A) provides a kind of viscoelastic damper that adopts and is installed in parallel the method controlling its flexural vibrations outside iron tower main material.Both all propose corresponding vibration isolation method for shaft tower itself or a part wherein, do not consider that shaft tower-lead/ground wire system and wind shake the coupling effect of controlling device and the randomness of wind field.Middle promulgated by the State Council name patent " high-voltage line aeolian vibration on-Line Monitor Device and method based on vibrating power-generation " (patent No. CN102288281A) proposes a kind of method detected power transmission line vibration amplitude or frequency based on vibration detection circuit, its wind mainly studying high-voltage line shakes detection, both do not proposed effective wind to shake administering method, and do not considered shaft tower-lead/ground wire system and wind yet and to shake the coupling effect of controlling device.

Summary of the invention

Technical problem to be solved by this invention, proposes a kind ofly to consider that the power transmission line transportation work style of stochastic matrix wind field and shaft tower-lead/interstructural fluid structurecoupling of earth system is shaken administering method exactly, improves power transmission line transportation work style further and to shake the science and validity of administering.

Method of the present invention, step comprises: step comprises: the simulation of S1 stochastic matrix wind field; S2 sets up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system; S3 to shake regulation effect according to the wind of stochastic matrix Wind Analysis transmission line, judges that shake intensity and determining of wind is installed wind and to be shaken controlling device.

The simulation of S1 stochastic matrix wind field

Based on multidimensional random vibration theory, according to the wind load time history sample under harmonic and reactive detection method generative approach wind speed, wind field is simulated;

In atmospheric boundary layer, wind field motion is that be assumed to the three-dimensional multivariable stationary random process with zero-mean, the wind field movement representation in cartesian coordinate system is about relevant each to non-homogeneous random process of Time and place:

$\left\{\begin{array}{c}U=\stackrel{\‾}{U}\left(z\right)+u(y,z,t)\\ v=v(y,z,t)\\ w=w(y,z,t)\end{array}\right.---\left(1\right)$

In formula, U is Longitudinal Incoming Flow wind speed (X-direction); longitudinal mean wind speed (X-direction); U, v, w are respectively longitudinally (X-direction), side direction (Y-direction) and vertical (Z-direction) fluctuating wind speed component; T is the time.

S1 implementation step is as follows:

S1-1 calculates mean wind speed

The describing method of mean wind speed mainly contains log law and exponential law, and choose A.G.Davenport exponential law theoretical, then the mean wind speed at arbitrary height place can be expressed as:

$\stackrel{\‾}{v}\left(z\right)=\stackrel{\‾}{v_b}{\left(\frac{z}{z_b}\right)}^{\mathrm{\α}}---\left(2\right)$

In formula, z _b-canonical reference height; for canonical reference At The Height obtains mean wind speed; Z-present level; the mean wind speed at present level place; α-surface roughness.

S1-2 calculates pulsating power spectrum

There is power in wind field, the longitudinal fluctuation wind speed spectrum of Kaimal:

$\frac{S_v(z,n)}{v_{*}^2}=\frac{{200x}_{*}}{{n(1+{50x}_{*})}^{5/3}}---\left(3\right)$

In formula: n-wind vibration frequency; v _*-ground friction speed, that is:

$v_{*}=\frac{k\·{\stackrel{\‾}{v}}_{10}}{\ln \left(\frac{10}{z_0}\right)}$

Wherein, k-Kaman (Karman) constant, k ≈ 0.4; the mean wind speed at height 10m place; z ₀-ground roughness length (m), gets 0.9; Z-height coordinate; for dimensionless coordinate.

S1-3 harmonic superposition and correlation calculations

Harmony superposition is the stationary random process method for numerical simulation proposed by Shinozuka etc., u _it () (i=1,2,3......m) is m the one dimension multivariate Gaussian stationary random process with zero-mean, its cross-spectral density matrix is:

$S\left(\mathrm{\ω}\right)=\left[\begin{array}{cccc}{S}_{11}\left(\mathrm{\ω}\right)& S_{12}\left(\mathrm{\ω}\right)& ...& S_{1m}\left(\mathrm{\ω}\right)\\ S_{21}\left(\mathrm{\ω}\right)& S_{22}\left(\mathrm{\ω}\right)& ...& S_{2m}\left(\mathrm{\ω}\right)\\ .& .& & .\\ .& .& & .\\ .& .& & .\\ S_{m1}\left(\mathrm{\ω}\right)& S_{m2}\left(\mathrm{\ω}\right)& ...& S_{\mathrm{mm}}\left(\mathrm{\ω}\right)\end{array}\right]---\left(4\right)$

In formula, S _ij(ω) (i=1,2......m; J=1,2......m) be cross-correlation function R _ij(τ) (i ≠ j) or auto-correlation function R _ii(τ) Fourier conversion.

Disregard the discrepancy in elevation change in the transmit direction of wire/ground wire, only consider its side direction correlation, its coefficient correlation can be expressed as:

$R(n,i,j)=\exp \left\{\frac{{-\mathrm{nC}}_y(y_i-y_j)}{\stackrel{\‾}{v_{\mathrm{ij}}}}\right\}---\left(5\right)$

In formula: C _yrepresent horizontal attenuation coefficient, E.Simin advises C _y=8, v _i, v _jrepresent i respectively, the mean wind speed of j point, ${\stackrel{\‾}{v}}_{\mathrm{ij}}=(v_i+v_j)/2;$

The crosspower spectrum of wind speed is:

Cholesky decomposition is carried out to S (ω), then:

S(ω)＝H(ω)H ^*(ω) ^T(6)

In formula, H (ω) is lower triangular matrix, H ^*(ω) ^tit is complex conjugate transpose;

H (ω) expression formula is as follows:

$H\left(\mathrm{\ω}\right)=\left[\begin{array}{cccc}{H}_{11}\left(\mathrm{\ω}\right)& 0& ...& 0\\ H_{21}\left(\mathrm{\ω}\right)& H_{22}\left(\mathrm{\ω}\right)& ...& 0\\ .& .& & .\\ .& .& & .\\ .& .& & .\\ S_{m1}\left(\mathrm{\ω}\right)& S_{m2}\left(\mathrm{\ω}\right)& ...& S_{\mathrm{mm}}\left(\mathrm{\ω}\right)\end{array}\right]---\left(7\right)$

Theoretical according to Shinozuka, random process { f _i(t) } sample can be simulated by following formula:

In formula: N is frequency isodisperse, the number of data samples namely in frequency domain, in order to utilize FFT technology, General N=2 ^α, α is positive integer; θ _il(ω _k) be the phase angle in structure between two different loads application points, for random phase angle equally distributed between 0 π ~ 2 π; Capping cut-off frequency is ω _u, its value can be estimated:

${\∫}_0^{{\mathrm{\ω}}_u}S\left(\mathrm{\ω}\right)\mathrm{d\ω}=(1-\mathrm{\ϵ}){\∫}_0^{\∞}S\left(\mathrm{\ω}\right)\mathrm{d\ω}---\left(9\right)$

S (ω) is power spectral density function, ε < < 1; according to the double subscript frequency concept that Shinozuka proposes, ω _kcan by following formula value:

${\mathrm{\&omega;}}_k=(k-1){\mathrm{\&Delta;\&omega;}}_k+\frac{l}{N}{\mathrm{\&Delta;\&omega;}}_k(k=\mathrm{1,2},...,N;l=\mathrm{1,2},...,m)---\left(10\right)$

In order to avoid analog result distortion, hits is not less than 2N, and incremental time Δ t should meet the following conditions:

$\mathrm{\&Delta;t}\&le;\frac{\mathrm{\&pi;}}{{\mathrm{\&omega;}}_u}$

Thus, the value of incremental time Δ t can be calculated as follows:

$\mathrm{\&Delta;t}=\frac{T_0}{M}=\frac{2\mathrm{\&pi;}}{\mathrm{M\&Delta;\&omega;}}=\frac{2N}{M}\&CenterDot;\frac{\mathrm{\&pi;}}{{\mathrm{\&omega;}}_u}---\left(11\right)$

In formula, M is the integer being not less than 2N, and it is hits.

S1-4 wind speed numerical simulation flow process

S1-5 wind speed and pressure is changed

According to blast-wind speed relation that Bernoulli equation draws, the dynamic pressure of wind is:

P＝0.5×ρ×v ²(12)

In formula, P is blast (kN/m ²), v is wind speed m/s, ρ is atmospheric density (kg/m ³); Pass due to atmospheric density ρ and severe r is r=ρ g, therefore has ρ=r/g, substitutes into formula (12), obtains:

P＝0.5×r×v ²/g (13)

In normal conditions, air pressure 1.013 × 10 can be got ⁵pa, temperature 15 DEG C, air severe r=0.01225kN/m ³; Latitude is the gravity acceleration g=9.8m/s at 45 ° of places ², obtain:

P＝v ²/1600 (14)

S2 sets up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system

S2 implementation step is as follows:

S2-1 sets up shaft tower respectively, leads the model of/ground wire, insulator;

S2-2, at the wire stretching force stress supposed in advance under specific meteorological condition and load, to lead by adopting/parabolic equation of ground wire carries out theoreticly approximately looking for shape to the leading of system/ground wire;

S2-3 adds model boundary condition.

S3 to shake regulation effect according to the wind of stochastic matrix Wind Analysis transmission line

Be blast by wind load time history sample conversion, power transmission line column line system loaded, utilizes simulation software, calculate axial stress-time history, the displacement versus time course of transmission tower, analyze and judge that the wind of structure shakes the effect of suppression;

Judge whether to exceed wind to shake intensity, when exceeding the limit of design, wind being installed when exceeding and shaking controlling device; Simulation analysis is carried out to the system after administering, improves regulation effect by prioritization scheme.

Beneficial effect: consider the hard and soft Dynamics Coupling of structure between electric power line pole tower, wire and ground wire in calculating of the present invention, and stochastic matrix wind field and shaft tower-lead/interstructural fluid structurecoupling of earth system, the wind proposed thus shakes administering method, has better implementation result.

Accompanying drawing explanation

Fig. 1 is calculation flow chart of the present invention;

Fig. 2 is the longitudinal wind speed-time history diagram in transmission tower segment number 2 place;

Fig. 3 is transmission tower-lead/ground wire coupling system model figure;

Fig. 4 (a) is the vibration displacement-time history curve chart of certain steel tower main material of second segment tower body before installation wind shakes controlling device;

Vibration displacement-time history the curve chart of certain steel tower of Fig. 4 (b) main material of second segment tower body after installation wind shakes controlling device.

Embodiment

Illustrate the implementation process of this explanation below, method of the present invention, step comprises: step comprises: the simulation of S1 stochastic matrix wind field; S2 sets up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system; S3 to shake regulation effect according to the wind of stochastic matrix Wind Analysis transmission line, judges that shake intensity and determining of wind is installed wind and to be shaken controlling device.

The simulation of S1 stochastic matrix wind field

Based on multidimensional random vibration theory, according to the wind load time history sample under harmonic and reactive detection method generative approach wind speed, wind field is simulated.

In atmospheric boundary layer, wind field motion is that be assumed to the three-dimensional multivariable stationary random process with zero-mean, the wind field movement representation in cartesian coordinate system is about relevant each to non-homogeneous random process of Time and place:

$\left\{\begin{array}{c}U=\stackrel{\&OverBar;}{U}\left(z\right)+u(y,z,t)\\ v=v(y,z,t)\\ w=w(y,z,t)\end{array}\right.---\left(1\right)$

In formula, U is Longitudinal Incoming Flow wind speed (X-direction); for longitudinal mean wind speed (X-direction); U, v, w are respectively longitudinally (X-direction), side direction (Y-direction) and vertical (Z-direction) fluctuating wind speed component; T is the time.

Initial parameter

The relevant initial parameter of input is as follows:

The span of certain transmission line is 250m, basic wind speed v ₁₀=20m/s; Landforms classification selects category-B, and terrain rough factor gets 0.16; Gradient level gets 350m; Return period regulation coefficient is μ _r=1.1; Sample frequency is f=1024; Δ ω=0.0634rad/s.

Tower body wind load is divided into 5 sections according to the difference of differing heights wind vibration factor value, and table 1 is power transmission tower Simulation of wind data.

Each node mean wind speed of table 1 tower body simulation

Segment number	Mean wind speed (m/s)	Segment number	Mean wind speed (m/s)
				1	18.4	4	22.7
2	20.6	5	23.3
				3	21.8

According to " delivery designing technique regulation " (DL/T5154-2002), tower body rod member Shape Coefficient gets μ _s=μ _st(1+ η), wherein, μ _st=0.7, η is then tabled look-up by the coefficient φ and flakiness ratio B/H that keeps out the wind of this section and determines; Power transmission line Shape Coefficient gets μ _s=1.1.

S1 implementation step is as follows:

S1-1 calculates mean wind speed

The description of mean wind speed mainly contains log law and exponential law, chooses A.G.Davenport exponential law theoretical in the present invention, and namely arbitrary height place obtains mean wind speed and can be expressed as:

$\stackrel{\&OverBar;}{v}\left(z\right)=\stackrel{\&OverBar;}{v_b}{\left(\frac{z}{z_b}\right)}^{\mathrm{\&alpha;}}---\left(2\right)$

In formula, z _b-canonical reference height; for canonical reference At The Height obtains mean wind speed; Z-present level; the mean wind speed at present level place; α-surface roughness.

Calculate mean wind speed

According to exponential law, calculate the mean wind speed will simulating each node:

In formula: α=0.16.The mean wind speed of 22m At The Height got by wire, the mean wind speed of 24m At The Height got by ground wire,

S1-2 pulsating power spectrum calculates

There is power in wind field, the longitudinal fluctuation wind speed spectrum of Kaimal:

$\frac{S_v(z,n)}{v_{*}^2}=\frac{{200x}_{*}}{{n(1+{50x}_{*})}^{5/3}}---\left(3\right)$

In formula: n-wind vibration frequency; v _*-ground friction speed, that is:

$v_{*}=\frac{k\&CenterDot;{\stackrel{\&OverBar;}{v}}_{10}}{\ln \left(\frac{10}{z_0}\right)}$

Wherein, k-Kaman (Karman) constant, k ≈ 0.4; the mean wind speed at height 10m place; z ₀-ground roughness length (m), gets 0.9; Z-height coordinate; for dimensionless Monin coordinate.

S1-3 harmonic superposition and correlation calculations

Harmony superposition (also known as spectrum solution) is the stationary random process method for numerical simulation proposed by Shinozuka etc., u _it () (i=1,2,3......m) is m the one dimension multivariate Gaussian stationary random process with zero-mean, its cross-spectral density matrix is:

$S\left(\mathrm{\&omega;}\right)=\left[\begin{array}{cccc}{S}_{11}\left(\mathrm{\&omega;}\right)& S_{12}\left(\mathrm{\&omega;}\right)& ...& S_{1m}\left(\mathrm{\&omega;}\right)\\ S_{21}\left(\mathrm{\&omega;}\right)& S_{22}\left(\mathrm{\&omega;}\right)& ...& S_{2m}\left(\mathrm{\&omega;}\right)\\ .& .& & .\\ .& .& & .\\ .& .& & .\\ S_{m1}\left(\mathrm{\&omega;}\right)& S_{m2}\left(\mathrm{\&omega;}\right)& ...& S_{\mathrm{mm}}\left(\mathrm{\&omega;}\right)\end{array}\right]---\left(4\right)$

In formula, S _ij(ω) (i=1,2......m; J=1,2......m) be cross-correlation function R _ij(τ) (i ≠ j) or auto-correlation function R _ii(τ) Fourier conversion.

Disregard the discrepancy in elevation change in the transmit direction of wire/ground wire, only consider its side direction correlation, its coefficient correlation can be expressed as:

$R(n,i,j)=\exp \left\{\frac{{-\mathrm{nC}}_y(y_i-y_j)}{\stackrel{\&OverBar;}{v_{\mathrm{ij}}}}\right\}---\left(5\right)$

In formula: C _yrepresent horizontal attenuation coefficient, E.Simin advises C _y=8, v _i, v _jrepresent i respectively, the mean wind speed of j point, ${\stackrel{\&OverBar;}{v}}_{\mathrm{ij}}=(v_i+v_j)/2;$

The crosspower spectrum of wind speed is:

Cholesky decomposition is carried out to S (ω):

S(ω)＝H(ω)H ^*(ω) ^T(6)

In formula, H (ω) is lower triangular matrix, H ^*(ω) ^tit is complex conjugate transpose;

H (ω) expression formula is as follows:

$H\left(\mathrm{\&omega;}\right)=\left[\begin{array}{cccc}{H}_{11}\left(\mathrm{\&omega;}\right)& 0& ...& 0\\ H_{21}\left(\mathrm{\&omega;}\right)& H_{22}\left(\mathrm{\&omega;}\right)& ...& 0\\ .& .& & .\\ .& .& & .\\ .& .& & .\\ S_{m1}\left(\mathrm{\&omega;}\right)& S_{m2}\left(\mathrm{\&omega;}\right)& ...& S_{\mathrm{mm}}\left(\mathrm{\&omega;}\right)\end{array}\right]---\left(7\right)$

Theoretical according to Shinozuka, random process { f _i(t) } sample can be simulated by following formula:

In formula: N is frequency isodisperse, the number of data samples namely in frequency domain, in order to utilize FFT technology, General N=2 ^α, α is positive integer; θ _il(ω _k) be the phase angle in structure between two different loads application points, for random phase angle equally distributed between 0 π ~ 2 π.Capping cut-off frequency is ω _u, its value can be estimated:

${\&Integral;}_0^{{\mathrm{\&omega;}}_u}S\left(\mathrm{\&omega;}\right)\mathrm{d\&omega;}=(1-\mathrm{\&epsiv;}){\&Integral;}_0^{\&infin;}S\left(\mathrm{\&omega;}\right)\mathrm{d\&omega;}---\left(9\right)$

S (ω) is power spectral density function, ε < < 1; according to the double subscript frequency concept that Shinozuka proposes, ω _kcan by following formula value:

${\mathrm{\&omega;}}_k=(k-1){\mathrm{\&Delta;\&omega;}}_k+\frac{l}{N}{\mathrm{\&Delta;\&omega;}}_k(k=\mathrm{1,2},...,N;l=\mathrm{1,2},...,m)---\left(10\right)$

In order to avoid analog result distortion, hits is not less than 2N, and incremental time Δ t should meet the following conditions:

$\mathrm{\&Delta;t}\&le;\frac{\mathrm{\&pi;}}{{\mathrm{\&omega;}}_u}$

Thus, the value of incremental time Δ t can be calculated as follows:

$\mathrm{\&Delta;t}=\frac{T_0}{M}=\frac{2\mathrm{\&pi;}}{\mathrm{M\&Delta;\&omega;}}=\frac{2N}{M}\&CenterDot;\frac{\mathrm{\&pi;}}{{\mathrm{\&omega;}}_u}---\left(11\right)$

In formula, M is the integer being not less than 2N, and it is hits.

S1-4 wind speed numerical simulation flow process

The flow process of wind speed simulation is as follows:

S1-4-1 chooses m point of space requirement simulation;

S1-4-2 calculates the mean wind speed at m some place according to exponential law;

S1-4-3 chooses longitudinally, horizontal and vertical power spectral density function, determines the upper cut off frequency ω simulated _u, and determine frequency isodisperse N, simulated time step delta _t, total step number;

S1-4-4 rated output spectrum matrix S (ω): 1. calculate φ (ω); 2. the correlation function R (n, i, j) of the different point-to-point transmission of computer memory; 3. cross-spectral density function S is calculated _ij(ω);

S1-4-5 uses formula (6) that spectral power matrix S (ω) is carried out Cholesky decomposition;

S1-4-6 uses formula (8) simulation each point wind speed: 1. generate random phase angle for random phase angle equally distributed between 0 π ~ 2 π; 2. ω is calculated _k; 3. θ is calculated _il(ω _k).

S1-5 wind speed and pressure is changed

According to blast-wind speed relation that Bernoulli equation draws, the dynamic pressure of wind is:

P＝0.5×ρ×v ²(12)

In formula, P is blast (kN/m ²), v is wind speed m/s, ρ is atmospheric density (kg/m ³).Pass due to atmospheric density ρ and severe r is r=ρ g, therefore has ρ=r/g, substitutes into formula (12), obtains:

P＝0.5×r×v ²/g (13)

In normal conditions, air pressure 1.013 × 10 can be got ⁵pa, temperature 15 DEG C, air severe r=0.01225kN/m ³.Latitude is the gravity acceleration g=9.8m/s at 45 ° of places ², obtain:

P＝v ²/1600 (14)

Wind speed-time history curve

Obtain the blast on transmission tower and wire, for the segment number 2 of shaft tower, the longitudinal wind speed-time history curve of its fluctuating wind as shown in Figure 2.

S2 sets up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system

S2 implementation step is as follows:

S2-1 sets up shaft tower respectively, leads the model of/ground wire, insulator;

S2-2, at the wire stretching force stress supposed in advance under specific meteorological condition and load, to lead by adopting/parabolic equation of ground wire carries out theoreticly approximately looking for shape to the leading of system/ground wire;

S2-3 adds model boundary condition.

Adopt ANSYS software, set up shaft tower space steel frame model, and look for shape to obtain span inside conductor model by wire, as shown in Figure 3.

S3 to shake regulation effect according to the wind of stochastic matrix Wind Analysis transmission line

Be blast by wind load time history sample conversion, power transmission line column line system loaded, utilizes simulation software, calculate axial stress-time history, the displacement versus time course of transmission tower, analyze and judge that wind shakes regulation effect;

Adopt the wind vibration response of random vibration theory to large span power transmission tower one line system to analyze, the fluctuating wind obtained is carried in the enterprising action edge Epidemiological Analysis of electric power pylon, the response of simulation 50s.Fig. 4 (a) is the vibration displacement-time history curve of certain steel tower main material of second segment tower body before installation wind shakes controlling device.

Judge that exceeding wind shakes strength degree, determine to take wind to shake control measures, then by simulation analysis, Fig. 4 (b) is depicted as certain steel tower installing wind and shakes the vibration displacement-time history curve of the main material of second segment tower body after controlling device.

To shake resolution by adjusting different wind, its wind can be assessed and to shake regulation effect, and optimizing resolution.

Claims (1)

1. the power transmission line transportation work style calculated based on simulation stochastic matrix wind field is shaken an administering method, and step comprises: the simulation of S1 stochastic matrix wind field; S2 sets up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system; S3 to shake regulation effect according to the wind of stochastic matrix Wind Analysis transmission line, judges that shake intensity and determining of wind is installed wind and to be shaken controlling device;

The simulation of S1 stochastic matrix wind field

Based on multidimensional random vibration theory, according to the wind load time history sample under harmonic and reactive detection method generative approach wind speed, wind field is simulated:

In atmospheric boundary layer, wind field motion is that be assumed to the three-dimensional multivariable stationary random process with zero-mean, the wind field movement representation in cartesian coordinate system is about relevant each to non-homogeneous random process of Time and place:

$\left\{\begin{array}{c}U=\stackrel{\&OverBar;}{U}\left(z\right)+u(y,z,t)\\ v=v(y,z,t)\\ w=w(y,z,t)\end{array}\right.---\left(1\right)$

In formula, U is the Longitudinal Incoming Flow wind speed of X-direction; for longitudinal mean wind speed of X-direction; U, v, w are respectively longitudinal, the side direction of X-direction, Y-direction and Z-direction and vertical fluctuating wind speed component; T is the time;

S1 implementation step is as follows:

S1-1 calculates mean wind speed

Choose A.G.Davenport exponential law theoretical, then the mean wind speed at arbitrary height place can be expressed as:

$\stackrel{\&OverBar;}{v}\left(z\right)=\stackrel{\&OverBar;}{v_b}{\left(\frac{z}{z_b}\right)}^{\mathrm{\&alpha;}}---\left(2\right)$

In formula, z _b-canonical reference height; -obtain mean wind speed for canonical reference At The Height; Z-height coordinate; the mean wind speed at-present level place; α-surface roughness;

S1-2 pulsating power spectrum calculates

There is power in wind field, the longitudinal fluctuation wind speed spectrum of Kaimal:

$\frac{S_v(z,n)}{v_{*}^2}=\frac{{200x}_{*}}{{n(1+{50x}_{*})}^{5/3}}---\left(3\right)$

In formula: n-wind vibration frequency; v _*-ground friction speed, that is:

$v_{*}=\frac{k\&CenterDot;{\stackrel{\&OverBar;}{v}}_{10}}{\ln \left(\frac{10}{z_0}\right)}$

Wherein, k-Kaman (Karman) constant, k ≈ 0.4; the mean wind speed at-height 10m place; z ₀-ground roughness length (m), gets 0.9; Z-height coordinate; for dimensionless coordinate;

S1-3 harmonic superposition and correlation calculations

Harmony superposition is the stationary random process method for numerical simulation proposed by Shinozuka etc., u _it () (i=1,2,3......m) is m the one dimension multivariate Gaussian stationary random process with zero-mean, its spectral power matrix is:

$S\left(\mathrm{\&omega;}\right)=\left[\begin{array}{cccccc}{S}_{11}\left(\mathrm{\&omega;}\right)& S_{12}\left(\mathrm{\&omega;}\right)& .& .& .& S_{1m}\left(\mathrm{\&omega;}\right)\\ S_{21}\left(\mathrm{\&omega;}\right)& S_{22}\left(\mathrm{\&omega;}\right)& .& .& .& S_{2m}\left(\mathrm{\&omega;}\right)\\ .& .& & & & .\\ .& .& & & & .\\ .& .& & & & .\\ S_{m1}\left(\mathrm{\&omega;}\right)& S_{m2}\left(\mathrm{\&omega;}\right)& .& .& .& S_{\mathrm{mm}}\left(\mathrm{\&omega;}\right)\end{array}\right]---\left(4\right)$

In formula, S _ij(ω) (i=1,2......m; J=1,2......m) be cross-correlation function R _ij(τ) (i ≠ j) or auto-correlation function R _ii(τ) Fourier conversion;

Disregard and lead/ground wire discrepancy in elevation change in the transmit direction, only consider its side direction correlation, its coefficient correlation can be expressed as:

$R(n,i,j)=\exp \{\frac{-n{C}_y(y_i-y_j)}{\stackrel{\&OverBar;}{v_{\mathrm{ij}}}}---\left(5\right)$

In formula: C _yrepresent horizontal attenuation coefficient, get C _y=8, v _i, v _jrepresent i respectively, the mean wind speed of j point, ${\stackrel{\&OverBar;}{v}}_{\mathrm{ij}}=(v_i+v_j)/2;$

The crosspower spectrum of wind speed is:

Cholesky decomposition is carried out to S (ω), then:

S(ω)＝H(ω)H ^*(ω) ^T(6)

In formula, H (ω) is lower triangular matrix, H ^*(ω) ^tit is complex conjugate transpose;

H (ω) is expressed as follows:

$H\left(\mathrm{\&omega;}\right)=\left[\begin{array}{cccccc}{H}_{11}\left(\mathrm{\&omega;}\right)& 0& .& .& .& 0\\ H_{21}\left(\mathrm{\&omega;}\right)& H_{22}\left(\mathrm{\&omega;}\right)& .& .& .& 0\\ .& .& & & & .\\ .& .& & & & .\\ .& .& & & & .\\ H_{m1}\left(\mathrm{\&omega;}\right)& H_{m2}\left(\mathrm{\&omega;}\right)& .& .& .& H_{\mathrm{mm}}\left(\mathrm{\&omega;}\right)\end{array}\right]---\left(7\right)$

Theoretical according to Shinozuka, random process u _it the sample of () can be simulated by following formula:

In formula: N is frequency isodisperse, the number of data samples namely in frequency domain, in order to utilize FFT technology, gets N=2 ^α, α is positive integer; θ _il(ω _k) be the phase angle in structure between two different loads application points, for random phase angle equally distributed between 0 π ~ 2 π; Capping cut-off frequency is ω _u, its value can be estimated:

${\&Integral;}_0^{{\mathrm{\&omega;}}_u}S\left(\mathrm{\&omega;}\right)\mathrm{d\&omega;}=(1-\mathrm{\&epsiv;}){\&Integral;}_0^{\&infin;}S\left(\mathrm{\&omega;}\right)\mathrm{d\&omega;}---\left(9\right)$

S (ω) is spectral power matrix, ε < < 1; according to the double subscript frequency concept that Shinozuka proposes, ω _kcan by following formula value:

${\mathrm{\&omega;}}_k=(k-1)\mathrm{\&Delta;}{\mathrm{\&omega;}}_k+\frac{l}{N}\mathrm{\&Delta;}{\mathrm{\&omega;}}_k(k=\mathrm{1,2},...,N;l=\mathrm{1,2},...,m)---\left(10\right)$

In order to avoid simulation result distortion, hits is not less than 2N, and incremental time Δ t should meet:

$\mathrm{\&Delta;t}\&le;\frac{\mathrm{\&pi;}}{{\mathrm{\&omega;}}_u}$

Thus, the value of incremental time Δ t can be calculated as follows:

$\mathrm{\&Delta;t}=\frac{T_0}{M}=\frac{2\mathrm{\&pi;}}{\mathrm{M\&Delta;\&omega;}}=\frac{2N}{M}\&CenterDot;\frac{\mathrm{\&pi;}}{{\mathrm{\&omega;}}_u}---\left(11\right)$

In formula, M is the integer being not less than 2N, and it is hits;

S1-4 wind speed numerical simulation

Step is as follows:

S1-4-1 chooses m point of space requirement simulation;

S1-4-2 calculates the mean wind speed at m some place according to A.G.Davenport exponential law;

S1-4-3 chooses longitudinal direction, side direction and vertical power spectral density function, determines the upper cut-off frequency ω simulated _u, and determine frequency isodisperse N, incremental time Δ t, hits M;

S1-4-4 rated output spectrum matrix S (ω): 1. calculate φ (ω); 2. the correlation function R (n, i, j) of the different point-to-point transmission of computer memory; 3. cross-spectral density function S is calculated _ij(ω);

S1-4-5 uses formula (6) that spectral power matrix S (ω) is carried out Cholesky decomposition;

S1-4-6 uses formula (8) simulation each point wind speed: 1. generate random phase angle for random phase angle equally distributed between 0 π ~ 2 π; 2. ω is calculated _k; 3. θ is calculated _il(ω _k);

S1-5 wind speed and pressure is changed

According to blast-wind speed relation that Bernoulli equation draws, the dynamic pressure of wind is:

P＝0.5×ρ×v ²(12)

In formula, P is blast (kN/m ²), v is wind speed m/s, ρ is atmospheric density (kg/m ³); Pass due to atmospheric density ρ and severe r is r=ρ g, therefore has ρ=r/g, substitutes into formula (12), obtains:

P＝0.5×r×v ²/g (13)

In normal conditions, air pressure 1.013 × 10 can be got ⁵pa, temperature 15 DEG C, air severe r=0.01225kN/m ³; Latitude is the gravity acceleration g=9.8m/s at 45 ° of places ², obtain:

P＝v ²/1600 (14)

S2 sets up shaft tower-lead/ground wire-wind and to shake the kinetic model of controlling device integral system

S2 implementation step is as follows:

S2-1 sets up transmission tower respectively, leads the model of/ground wire, insulator;

S2-2 is supposing leading under specific meteorological condition/ground wire stretching force stress and load in advance, lead by adopting/parabolic equation of ground wire to by transmission tower, lead/ground wire, the leading of system that insulator is formed/ground wire carries out theoreticly approximately looking for shape;

S2-3 adds model boundary condition;

S3 to shake regulation effect according to the wind of stochastic matrix Wind Analysis transmission line

Be blast by wind load time history sample conversion, to by transmission tower, lead/ground wire, system that insulator is formed loads, utilize simulation software, calculate axial stress-time history, the displacement versus time course of transmission tower, analyze and judge that the wind of transmission tower structure shakes intensity, when exceeding design limit, installation wind shakes controlling device; Simulation analysis is carried out to shaft tower-lead/ground wire-wind controlling device integral system that shakes, improves regulation effect by prioritization scheme.