CN104167076B - A kind of icing transmission line of electricity weak link method for early warning - Google Patents

Abstract

The invention discloses a kind of icing transmission line of electricity weak link method for early warning, comprise the following steps: 1, determine Weather Forecast Information, icing information, transmission line information, 2, the real-time stress value of each grade in accurate model Stress calculation model based on transmission line wire solves strain insulator tower section, and calculate suffered out-of-balance force on shaft tower, 3, the numerical relation of real-time stress value and limit stress value is analyzed, graduation carries out wire early warning, relatively shaft tower out-of-balance force and limit out-of-balance force, graduation carries out shaft tower early warning.The present invention is capable of power system and is in the intelligent decision that transmission line wire is broken period by icing.By the comprehensive collection to information, use ruling span computation model and each shelves stress value of accurate Stress calculation model measurement circuit, thus it being accurately judged to whether circuit is in the danger of broken string, it is to avoid traditional determination methods is not directly, precision is low, the shortcoming of time-consuming length.

Description

A kind of icing transmission line of electricity weak link method for early warning

Technical field

The invention belongs to power system icing disaster Prevention-Security, particularly a kind of pre-police of icing transmission line of electricity weak link Method.

Background technology

Owing to China is vast in territory, geographical environment is complicated and climate type is diversified, and extreme frequent natural calamity is sent out Raw, the typhoon disaster often occurred such as the annual southeastern coastal areas, the ice damage etc. in the Yunnan-Guizhou Plateau and Sanxia area.Extreme at these Under weather condition, transmission line of electricity load can exceed its design ability to bear, causes power transmission line stress can occur significantly to change, Thus cause electric network fault.As in ice disaster in 2008, due to long sleet, transmission line of electricity create serious Icing, causes the change of the stress of conductor, causes that the stress of conductor is excessive causes transmission line of electricity wire breaking and tower falling accident.Therefore, at electrical network Design, operation and fault post analysis often need the circuit under extreme weather conditions is carried out Mechanics Calculation.

At present, it is commonly used to judge that the method that icing transmission line wire in period breaks has two kinds: a kind of by wire Sag judges its stress value；Another kind is to obtain ice thickness data, further according to warp by special ice covering thickness monitoring device Test and judge whether the substantially suffered stress of wire is in risk range.The common weak point of above-mentioned both approaches is, indirectly Obtain stress value, lack degree of accuracy；First method needs relevant staff to go in-site measurement sag, not only labor intensive money Source, and the longest；Second method relies on expertise, inadequate automatization, and degree of accuracy is relatively low.

Summary of the invention

Technical problem solved by the invention is to provide a kind of icing transmission line of electricity weak link method for early warning.

The technical solution realizing the object of the invention is: a kind of icing transmission line of electricity weak link method for early warning, including Following steps:

Step 1, determining weather information, ice covering thickness information and overhead transmission line details, described weather information is specifically wrapped Include: real time temperature t, highest temperature t_max, lowest temperature t_min, temperature on average t_avThe temperature on average t produced with icing_ice；Icing is thick The ice covering thickness b of each shelves of the most continuous shelves of degree information；Overhead transmission line details specifically include wire type, this wire type correspondence Coefficient of elasticity E, sectional area A, outer diameter D, linear mass q, each shelves span l_i0, each shelves discrepancy in elevation h_i0, each shelves discrepancy in elevation angle beta_i0、 The length lambda of suspension string on each base tangent tower_i, vertical load G_i, stringing time temperature t₀, each shelves horizontal stress σ under stringing temperature₀₀；

Step 2, according to known weather information, determine initial level stress by ruling span method computation model, then by The real-time stress value σ of each grade in accurately Stress calculation model determines strain insulator tower section_i；Specifically include following several step:

Step 2-1, determine limit stress σ of transmission line wire_lim；Formula used is:

${\mathrm{\σ}}_{\lim }=\frac{T_b\×0.4}{A}$

In formula, T_bFor the calculating pull-off force of wire, A is wire cross-section area.

Step 2-2, determine and represent discrepancy in elevation angle beta_rWith ruling span l_r；Formula used is respectively as follows:

$\cos {\mathrm{\β}}_r=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}(l_{i0}/\cos {\mathrm{\β}}_{i0})}{\underset{1}{\overset{n}{\mathrm{\Σ}}}(l_{i0}/{\cos }^2{\mathrm{\β}}_{i0})}$

In formula, β_rWait to ask, for representing height difference angle, l_i0It is i-th grade of span, β_i0Being i-th grade of height difference angle, i from 1 to n is just Integer, n is gear number；

$l_r=\frac{1}{\cos {\mathrm{\β}}_r}\sqrt{\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{l}_{i0}^3\cos {\mathrm{\β}}_{i0}}{\underset{1}{\overset{n}{\mathrm{\Σ}}}(l_{i0}/\cos {\mathrm{\β}}_{i0})}}$

In formula, l_rWait to ask, for ruling span, β_rFor representing height difference angle, l_i0It is i-th grade of span, β_i0It is i-th grade of height difference angle, i For the positive integer from 1 to n, n is gear number；

Step 2-3, by ruling span method computation model, utilize temperature t when installing electric wiring₀With transmission line wire Parameter, calculates highest temperature t_max, lowest temperature t_min, temperature on average t_avRespective stress value under three kinds of meteorological conditions, by stress Value is closest to horizontal stress design load σ_iInitial as accurate Stress calculation model of the meteorological condition corresponding to calculating state The final states meteorological condition calculated in meteorological condition, and following step 2-5；Described ruling span method computation model is as follows:

${\mathrm{\σ}}_{02}-\frac{E{\mathrm{\γ}}_2^2{l}_r^2{\cos }^3{\mathrm{\β}}_r}{24{\mathrm{\σ}}_{02}^2}={\mathrm{\σ}}_{01}-\frac{E{\mathrm{\γ}}_1^2{l}_r^2{\cos }^3{\mathrm{\β}}_r}{24{\mathrm{\σ}}_{01}^2}-\mathrm{\αE}(t_2-t_1)\cos {\mathrm{\β}}_r$

In formula, numeral 1 represents initial meteorology, and numeral 2 represents end meteorology, and E is the bullet of transmission line wire Property coefficient, α is the linear expansion coefficient of transmission line wire, and t is temperature, σ₀₁For initial state horizontal stress, σ₀₂Should for final states level Power, l_γFor ruling span, β_γFor representing height difference angle, γ is ratio load, γ=q*g/A, and wherein q is conductor quality, and g is Acceleration of gravity, A is wire cross-section area.

Step 2-4, again by ruling span method computation model, utilize temperature t when installing electric wiring₀, icing produce Temperature on average t_iceWith the parameter of transmission line wire, determine that the wire always ratio that different ice covering thickness is corresponding carries γ_bUnder the conditions of should Force value, by stress value closest to limit σ_limThe meteorological condition corresponding to calculating state as the initial gas in following step 2-5 As condition；The wire always ratio that described different ice covering thickness is corresponding carries γ_bComputing formula is:

${\mathrm{\γ}}_b=\frac{9.81q+0.03b(b+D)}{A}$

In formula, q is the unit mass of wire, and D is the external diameter of wire, b ice covering thickness, and A is wire cross-section area.

Step 2-5, utilization the final states meteorological condition as described in step 2-3 in calculation process, the initial gas as described in step 2-4 As condition, and set limit stress σ_limFor initial stress values, third time uses ruling span method computation model, tries to achieve initial water Horizontal stress value σ₀, and using it as the initial level stress of accurate Stress calculation model；

Step 2-6, according to all known real-time weather conditions, in using accurate Stress calculation model to determine strain insulator tower section The real-time stress value σ of each grade_i；Described accurate Stress calculation model includes three below relational model:

(1) span increment Delta l_iWith horizontal stress σ_iBetween relational model:

$\begin{array}{c}\mathrm{\Δ}{l}_i=\left\{\right[{\left(\frac{{\mathrm{\γ}}_0}{{\mathrm{\σ}}_0}\right)}^2-{\left(\frac{{\mathrm{\γ}}_i}{{\mathrm{\σ}}_i}\right)}^2]\frac{l_{i0}^2{\cos }^2{\mathrm{\β}}_{i0}}{24}+\left(\frac{{\mathrm{\σ}}_i-{\mathrm{\σ}}_0}{E\cos {\mathrm{\β}}_{i0}}\right)+\mathrm{\α}(t-t_0)-\frac{\mathrm{\Δ}{h}_i}{2l_{i0}}{\cos }^2{\mathrm{\β}}_{i0}\}\\ \×\frac{l_{i0}}{{\cos }^2{\mathrm{\β}}_{i0}(1+{\mathrm{\γ}}_i^2{l}_{i0}^2/8{{\mathrm{\σ}}_i}^2)}\end{array}$

σ in formula_iTo be evaluated, it is the horizontal stress of i-th grade, specially i-th grade is t at temperature, is γ than carrying_iUnder Electric wire horizontal stress；I is the positive integer from 1 to n, and n is gear number；

σ₀Initial level stress value；

l_i0I-th grade of span；

γ₀、γ_iThan carrying and ratio load after wire icing, γ before wire icing₀For q*g/A, γ_iFor q*g/A+ 0.027728 (b (b+D)/A), wherein q is conductor quality, and g is acceleration of gravity, and A is wire cross-section area, and b is Wire icing thickness, D is wire diameter；

Δl_iTo be evaluated, the l of i-th grade of span_i0Increment, specially i-th grade span than stringing situation suspension string at The increment of span during vertical position in；

Δh_iTo be evaluated, i-th grade of discrepancy in elevation h_i0Increment, between specially i-th grade two ends suspension string deflection aft hook Discrepancy in elevation h_i0Variable quantity, the high left hitch point person h of right hitch point_i0And discrepancy in elevation angle beta_i0For on the occasion of；

t、t₀Temperature when being respectively real time temperature and stringing；

The α conductor temperature coefficient of expansion；

E wire coefficient of elasticity；

(2) i-th grades of discrepancy in elevation increment Delta h_iWith the i-th base tower hitch point skew δ_iBetween relational model:

$\mathrm{\Δ}{h}_i=\sqrt{{\mathrm{\λ}}^2-{\mathrm{\δ}}_{i-1}^2}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2}$

Δ h in formula_iTo be evaluated, i-th grade of discrepancy in elevation h_i0Increment, i is the positive integer from 1 to n, and n is gear number；

δ_i、δ_i-1The horizontal range of hitch point skew on i-th grade of two ends i-th-1 Ji Ta, the δ of both end of which anchor support is 0；

Suspension insulator string length on each shaft tower of λ, both end of which anchor support has also assumed that λ, but δ has been 0；

(3) i-th base tower hitch point skew δ_iAnd σ between horizontal stress_iRelational model:

$\begin{array}{c}{\mathrm{\σ}}_{i+1}=\{(\frac{G_i}{2A}+\frac{{\mathrm{\γ}}_i{l}_{i0}}{2\cos {\mathrm{\β}}_{i0}}+\frac{{\mathrm{\γ}}_{(i+1)}{l}_{(i+1)0}}{2\cos {\mathrm{\β}}_{(i+1)0}}+\frac{{\mathrm{\σ}}_i{h}_{i0}}{l_{i0}})+\frac{{\mathrm{\σ}}_i}{{\mathrm{\δ}}_i}\sqrt{{{\mathrm{\λ}}_i}^2-{{\mathrm{\δ}}_i}^2}\}\\ \÷(\frac{1}{{\mathrm{\δ}}_i}\sqrt{{{\mathrm{\λ}}_i}^2-{{\mathrm{\δ}}_i}^2}+\frac{h_{(i+1)0}}{l_{(i+1)0}})\end{array}$

σ in formula_iTo be evaluated, it is i-th grade of horizontal stress, specially i-th grade is t at temperature, is γ than carrying_iUnder electricity Line horizontal stress；I is the positive integer from 1 to n, and n is gear number；

δ_i——δ_i=δ_i-1+Δl_i；

A wire cross-section area；

γ_iThan carrying after wire icing, γ_iFor q*g/A+0.03 (b (b+D)/A), wherein q is conductor matter Amount, g is acceleration of gravity, and A is wire cross-section area, and b is wire icing thickness, and D is wire diameter；

δ_iThe horizontal range of hitch point skew on i-th grade of two end group tower, the δ of both end of which anchor support is 0；

G_i, the vertical load of suspension insulator on each shaft tower of λ and length, both end of which anchor support also assumes that There is λ, but δ is 0；

l_i0I-th grade of span；

h_i0、h_(i+1)0I-th grade and the i+1 shelves discrepancy in elevation, during specially suspension string is in during vertical position, the i-th base straight line On tower, electric wire hitch point is just to the discrepancy in elevation between adjacent tower i-th-1 and i+1 base hitch point, large size than small size tower height person h value itself Value, on the contrary it is negative value, and scene records；

β_i0I-th grade of height difference angle.

Step 3, stress σ by each span inside conductor determined in step 2_i, determine suffered out-of-balance force on each shaft tower ΔF_i；The computation model of described shaft tower unbalanced tensile force is:

ΔF_i=(σ_i+1-σ_i) A=F_i+1-F_i(i=1,2 ..., n-1)

In formula: σ_i+1And σ_iBeing respectively i+1 shelves and the horizontal stress of i-th grade of electric wire, i is the positive integer from 1 to n-1, n For gear number；

A is the sectional area of electric wire；

F_i+1And F_iFor i+1 and the Horizontal Tension of i-th grade of electric wire；

ΔF_iThe unbalanced tensile force born in i-th base straight line pole ice detachment is poor；

Step 4, by each span inside conductor stress σ_iWith its limit stress σ_limComparing, it is pre-that graduation carries out wire Alert；By out-of-balance force Δ F on each shaft tower_iDesign with it and can bear out-of-balance force Δ F_sComparing, graduation carries out shaft tower not Equilibrant early warning；

The concrete numerical relation of described wire early warning with corresponding advanced warning grade is:

Work as σ_i< 50% σ_limTime, not early warning；

As 50% σ_lim≤σ_i≤ 70% σ_limTime, export i-th grade of wire yellow early warning；

As 70% σ_lim<σ_i< 85% σ_limTime, export i-th grade of orange early warning of wire；

Work as σ_i>=85% σ_limTime, export i-th grade of wire red early warning.

The concrete numerical relation of described shaft tower out-of-balance force early warning with corresponding advanced warning grade is:

As Δ F_i≤ 0.6 Δ Fs, not early warning；

As 0.6 Δ Fs < Δ F_i< 0.8 Δ Fs exports the i-th base shaft tower yellow early warning；

As 0.8 Δ Fs≤Δ F_i≤ 0.95 Δ Fs, exports the i-th orange early warning of base shaft tower；

As Δ F_i> 0.95 Δ Fs, export the i-th base shaft tower red early warning.

Compared with prior art, its remarkable advantage is the present invention: 1) directly obtains circuit stress value, omits intermediate link, Precision higher and save in-site measurement sag manpower and materials cost；2) mathematical model is used to calculate circuit stress value, automatization Degree is higher.

Below in conjunction with the accompanying drawings the present invention is described in further detail.

Accompanying drawing explanation

Fig. 1 is the icing transmission line of electricity weak link method for early warning flow chart of the present invention.

Detailed description of the invention

In conjunction with Fig. 1, a kind of icing transmission line of electricity weak link method for early warning of the present invention, comprise the steps:

Step 1, determining weather information, icing information, overhead transmission line details, weather information specifically includes: temperature in real time Degree t, highest temperature t_max, lowest temperature t_min, temperature on average t_avThe temperature on average t produced with icing_ice；Ice covering thickness information is i.e. The ice covering thickness b of each shelves of shelves continuously；The elastic system that overhead transmission line details specifically include wire type, this wire type is corresponding Number E, sectional area A, outer diameter D, linear mass q, each shelves span l_i0, each shelves discrepancy in elevation h_i0, each shelves discrepancy in elevation angle beta_i0, each base straight line The length lambda of suspension string on tower_i, vertical load G_i, icing time temperature t, stringing time temperature t₀, each shelves level should under stringing temperature Power σ₀₀；The length lambda of suspension string on the most each base tangent tower_iLine inspection road design load obtains, vertical load G_iLooked into by suspension string model Table obtains.Real time temperature t is obtained by in-site measurement, temperature t during stringing₀, each shelves horizontal stress σ under stringing temperature₀₀Set by stringing Evaluation checks in；

Step 2, according to known weather information, determine initial level stress by ruling span method computation model, then by The real-time stress value σ of each grade in accurately Stress calculation model determines strain insulator tower section_i；Specifically include following several step:

Step 2-1, determine limit stress σ of transmission line wire_lim；Formula used is:

${\mathrm{\&sigma;}}_{\lim }=\frac{T_b\&times;0.4}{A}$

In formula, T_bFor the calculating pull-off force of wire, A is wire cross-section area.

Step 2-2, determine and represent discrepancy in elevation angle beta_rWith ruling span l_r；Formula used is respectively as follows:

$\cos {\mathrm{\&beta;}}_r=\frac{\underset{1}{\overset{n}{\mathrm{\&Sigma;}}}(l_{i0}/\cos {\mathrm{\&beta;}}_{i0})}{\underset{1}{\overset{n}{\mathrm{\&Sigma;}}}(l_{i0}/{\cos }^2{\mathrm{\&beta;}}_{i0})}$

In formula, β_rWait to ask, for representing height difference angle, l_i0It is i-th grade of span, β_i0Being i-th grade of height difference angle, i from 1 to n is just Integer, n is gear number；

$l_r=\frac{1}{\cos {\mathrm{\&beta;}}_r}\sqrt{\frac{\underset{1}{\overset{n}{\mathrm{\&Sigma;}}}{l}_{i0}^3\cos {\mathrm{\&beta;}}_{i0}}{\underset{1}{\overset{n}{\mathrm{\&Sigma;}}}(l_{i0}/\cos {\mathrm{\&beta;}}_{i0})}}$

In formula, l_rWait to ask, for ruling span, β_rFor representing height difference angle, l_i0It is i-th grade of span, β_i0It is i-th grade of height difference angle, i For the positive integer from 1 to n, n is gear number；

Step 2-3, by ruling span method computation model, utilize temperature t when installing electric wiring₀With transmission line wire Parameter, calculates highest temperature t_max, lowest temperature t_min, temperature on average t_avRespective stress value under three kinds of meteorological conditions, by stress Value is closest to horizontal stress design load σ_iInitial as accurate Stress calculation model of the meteorological condition corresponding to calculating state The final states meteorological condition calculated in meteorological condition, and following step 2-5；Described ruling span method computation model is as follows:

${\mathrm{\&sigma;}}_{02}-\frac{E{\mathrm{\&gamma;}}_2^2{l}_r^2{\cos }^3{\mathrm{\&beta;}}_r}{24{\mathrm{\&sigma;}}_{02}^2}={\mathrm{\&sigma;}}_{01}-\frac{E{\mathrm{\&gamma;}}_1^2{l}_r^2{\cos }^3{\mathrm{\&beta;}}_r}{24{\mathrm{\&sigma;}}_{01}^2}-\mathrm{\&alpha;E}(t_2-t_1)\cos {\mathrm{\&beta;}}_r$

In formula, numeral 1 represents initial meteorology, and numeral 2 represents end meteorology, and E is the bullet of transmission line wire Property coefficient, α is the linear expansion coefficient of transmission line wire, and t is temperature, σ₀₁For initial state horizontal stress, σ₀₂Should for final states level Power, l_γFor ruling span, β_γFor representing height difference angle, γ is ratio load, γ=q*g/A, and wherein q is conductor matter Amount, g is acceleration of gravity, and A is wire cross-section area.

Step 2-4, again by ruling span method computation model, utilize temperature t when installing electric wiring₀, icing produce Temperature on average t_iceWith the parameter of transmission line wire, calculate different ice covering thickness corresponding wire always ratio and carry γ_bUnder the conditions of should Force value, by stress value closest to limit σ_limThe meteorological condition corresponding to calculating state as the initial gas in following step 2-5 As condition；The wire always ratio that described different ice covering thickness is corresponding carries γ_bComputing formula is:

${\mathrm{\&gamma;}}_b=\frac{9.81q+0.03b(b+D)}{A}$

In formula, q is the unit mass of wire, and D is the external diameter of wire, and b is ice covering thickness, and A is wire cross-section area.

Step 2-5, utilization the final states meteorological condition as described in step 2-3 in calculation process, the initial gas as described in step 2-4 As condition, and set limit stress σ_limFor initial stress values, third time uses ruling span method computation model, tries to achieve initial water Horizontal stress value σ₀, and using it as the initial level stress of accurate Stress calculation model；

Step 2-6, according to all known real-time weather conditions, use accurate Stress calculation model to try to achieve in strain insulator tower section Horizontal stress σ during i-th grade of icing_i；The described utilization accurate Stress calculation real-time stress value of model solution specifically includes the most several Step:

(1) row write span change and wire stress between relational model:

$\begin{array}{c}\mathrm{\&Delta;}{l}_i=\left\{\right[{\left(\frac{{\mathrm{\&gamma;}}_0}{{\mathrm{\&sigma;}}_0}\right)}^2-{\left(\frac{{\mathrm{\&gamma;}}_i}{{\mathrm{\&sigma;}}_i}\right)}^2]\frac{l_{i0}^2{\cos }^2{\mathrm{\&beta;}}_{i0}}{24}+\left(\frac{{\mathrm{\&sigma;}}_i-{\mathrm{\&sigma;}}_0}{E\cos {\mathrm{\&beta;}}_{i0}}\right)+\mathrm{\&alpha;}(t-t_0)-\frac{\mathrm{\&Delta;}{h}_i}{2l_{i0}}{\cos }^2{\mathrm{\&beta;}}_{i0}\}\\ \&times;\frac{l_{i0}}{{\cos }^2{\mathrm{\&beta;}}_{i0}(1+{\mathrm{\&gamma;}}_i^2{l}_{i0}^2/8{{\mathrm{\&sigma;}}_i}^2)}\end{array}$ (formula 1) σ in formula_iTo be evaluated, it is i-th grade of horizontal stress, specially horizontal stress during i-th grade of icing, specially i-th grade at temperature For t, than carrying as γ_iUnder electric wire horizontal stress, unit is: N/mm²；

σ₀Initial level stress value, unit is: N/mm²；

l_i0I-th grade of span, unit is: m；

γ₀、γ_iThan carrying and ratio load after wire icing before wire icing, unit is: N/ (m mm²), γ₀For q*g/ A, γ_iFor q*g/A+0.03 (b (b+D)/A), wherein q is conductor quality, and unit is: kg/m, g are that gravity accelerates Degree, A is wire cross-section area, and unit is: mm², b is wire icing thickness, and unit is: mm, D are wire diameter, and unit is: mm；

Δl_iTo be evaluated, the l of i-th grade of span_i0Increment, specially i-th grade span than stringing situation suspension string at In in hang down position time span increment, the Δ l when span shortens_iThis is as negative value, and unit is: m；

Δh_iTo be evaluated, i-th grade of discrepancy in elevation h_i0Increment, between specially i-th grade two ends suspension string deflection aft hook Discrepancy in elevation h_i0Variable quantity, the high left hitch point person h of right hitch point_i0And discrepancy in elevation angle beta_i0For on the occasion of, unit is: m；

t、t₀Temperature when being respectively real time temperature and stringing, unit is: DEG C；

E, α wire coefficient of elasticity, unit is N/mm²；The conductor temperature coefficient of expansion, unit is 1/ DEG C；

(2) row write the relational model between the change of i-th grade of discrepancy in elevation and the skew of the i-th base tower hitch point:

$\mathrm{\&Delta;}{h}_i=(\mathrm{\&lambda;}-\sqrt{{\mathrm{\&lambda;}}^2-{{\mathrm{\&delta;}}_i}^2})-(\mathrm{\&lambda;}-\sqrt{{\mathrm{\&lambda;}}^2-{{\mathrm{\&delta;}}_{i-1}}^2})=\sqrt{{\mathrm{\&lambda;}}^2-{{\mathrm{\&delta;}}_{i-1}}^2}-\sqrt{{\mathrm{\&lambda;}}^2-{{\mathrm{\&delta;}}_i}^2}$ (formula 2) Δ h in formula_iTo be evaluated, i-th grade of discrepancy in elevation h_i0Increment, unit is: m；

δ_i、δ_i-1The horizontal range of hitch point skew, both end of which strain insulator on i-th grade of two ends i-th and i-th-1 Ji Ta The δ of tower is 0, and unit is: m；

Suspension insulator string length on each shaft tower of λ, unit is: m；

(3) row write the relational model between suspension string deflection and wire stress:

$\begin{array}{c}{\mathrm{\&sigma;}}_{i+1}=\{(\frac{G_i}{2A}+\frac{{\mathrm{\&gamma;}}_i{l}_{i0}}{2\cos {\mathrm{\&beta;}}_{i0}}+\frac{{\mathrm{\&gamma;}}_{(i+1)}{l}_{(i+1)0}}{2\cos {\mathrm{\&beta;}}_{(i+1)0}}+\frac{{\mathrm{\&sigma;}}_i{h}_{i0}}{l_{i0}})+\frac{{\mathrm{\&sigma;}}_i}{{\mathrm{\&delta;}}_i}\sqrt{{{\mathrm{\&lambda;}}_i}^2-{{\mathrm{\&delta;}}_i}^2}\}\\ \&divide;(\frac{1}{{\mathrm{\&delta;}}_i}\sqrt{{{\mathrm{\&lambda;}}_i}^2-{{\mathrm{\&delta;}}_i}^2}+\frac{h_{(i+1)0}}{l_{(i+1)0}})\end{array}$ (formula 3) δ in formula_i=δ_i-1+Δl_i(formula 4)

h_i0、h_(i+1)0I-th grade and the i+1 shelves discrepancy in elevation, during specially suspension string is in during vertical position, the i-th base straight line On tower, electric wire hitch point is just to the discrepancy in elevation between adjacent tower i-th-1 and i+1 base hitch point, large size than small size tower height person h value itself Value, on the contrary it is negative value, and unit is: m.

Above-mentioned 3n the equation of simultaneous, solves Δ l_i、Δh_i、σ_i03n unknown number, obtains each shelves wire horizontal stress σ altogether_i。

Step 3, stress σ by each span inside conductor determined in step 2_i, determine suffered out-of-balance force on each shaft tower ΔF_i；

The computation model of described shaft tower unbalanced tensile force is:

ΔF_i=(σ_i+1-σ_i) A=F_i+1-F_i(i=1,2 ..., n-1)

In formula: σ_i+1And σ_iHorizontal stress when being respectively i+1 shelves and i-th grade of icing, i is the positive integer from 1 to n-1, n For gear number；

A is wire cross-section area；

F_i+1And F_iFor i+1 and the Horizontal Tension of i-th grade of electric wire；

ΔF_iThe unbalanced tensile force born in i-th base straight line pole ice detachment is poor；

Step 4, by each span inside conductor stress σ_iWith its limit stress σ_limComparing, it is pre-that graduation carries out wire Alert；By out-of-balance force Δ F on each shaft tower_iDesign with it and can bear out-of-balance force Δ F_sComparing, graduation carries out shaft tower not Equilibrant early warning；

The concrete numerical relation of described wire early warning with corresponding advanced warning grade is:

Work as σ_i< 50% σ_limTime, not early warning；

As 50% σ_lim≤σ_i≤ 70% σ_limTime, export i-th grade of wire yellow early warning；

As 70% σ_lim<σ_i< 85% σ_limTime, export i-th grade of orange early warning of wire；

Work as σ_i>=85% σ_limTime, export i-th grade of wire red early warning.

The concrete numerical relation of described shaft tower out-of-balance force early warning with corresponding advanced warning grade is:

As Δ F_i≤ 0.6 Δ Fs, not early warning；

As 0.6 Δ Fs < Δ F_i< 0.8 Δ Fs exports the i-th base shaft tower yellow early warning；

As 0.8 Δ Fs≤Δ F_i≤ 0.95 Δ Fs, exports the i-th orange early warning of base shaft tower；

As Δ F_i> 0.95 Δ Fs, export the i-th base shaft tower red early warning.

Below in conjunction with embodiment the present invention done further detailed description:

Embodiment 1

One icing scene, is made up of a strain section continuous print 6 grades.Real time temperature t=-5 DEG C, the highest temperature 40 DEG C, Low temperature-20 DEG C, temperature on average 15 DEG C, temperature t during stringing₀=10 DEG C.Each shelves ice covering thickness value b_i=[10mm 15mm15mm 25mm 20mm 20mm].Transmission line wire model is LGJ-300/40, coefficient of elasticity E=73000N/ that this wire is corresponding mm², sectional area A=338.99mm², outer diameter D=23.94mm, linear mass q=1.133kg/m, temperature expansion coefficient α= 19.6/ DEG C, corresponding ultimate tension be 92220N, each shelves span l_i0=[350m 400m 450m500m 500m 350m], respectively Shelves discrepancy in elevation h_i0=[20m 20m 10m-10m-20m-20m], the length lambda of suspension string on each base tangent tower_i(m)=5.2m, hang down To load G_i=2300N, initial level stress σ under stringing temperature₀₀=51N/mm²。

Step 1, determine that meteorological data, ice covering thickness and overhead transmission line details are described above.

Step 2, by ruling span computation model calculate accurate stress model initial level stress.

Step 2-1, limit stress σ of computing electric power line wire_lim=108.82N；

Step 2-2, calculating ruling span l_r=435.5888m with represent height difference angle cosine cos β_r=0.9991；

Step 2-3, by ruling span method computation model, utilize temperature t when installing electric wiring₀With transmission line wire Parameter, calculates highest temperature t_max, lowest temperature t_min, temperature on average t_avnRespective stress value under three kinds of meteorological conditions, by stress Value is closest to horizontal stress design load σ₀₀Initial as accurate Stress calculation model of the meteorological condition corresponding to calculating state The final states meteorological condition calculated in meteorological condition, and following step 2-5；

Obtain the stress value 50.74N/mm under temperature on average²Closest to horizontal stress design load 51N/mm², therefore, will be average Temperature meteorological condition is as the initial meteorological condition of accurate Stress calculation model.

Step 2-4, again by ruling span method computation model, utilize temperature t when installing electric wiring₀, icing produce Temperature on average t_iceWith the parameter of transmission line wire, calculate different ice covering thickness corresponding wire always ratio and carry γ_bUnder the conditions of should Force value, by stress value closest to limit σ_limThe meteorological condition corresponding to calculating state as the initial gas in following step 2-5 As condition；

Step 2-5, utilize final states meteorological condition as described in step 2-3, step 2-4 in calculation process, initial gas as bar Part, and set limit stress σ_limFor initial stress values, third time uses ruling span method computation model, and trying to achieve initial level should Force value σ₀=52.27N/mm², and using it as the initial level stress of accurate Stress calculation model；

Step 2-6, according to all known real-time weather conditions, accurate Stress calculation model every in trying to achieve strain insulator tower section The real-time stress value σ of one grade_i。

Step 3, accurate Stress calculation model is used to calculate every grade of horizontal stress；

σ₁=121.14N/mm²、σ₂=123.88N/mm²、σ₃=130.20N/mm²、σ₄=145.83N/mm²、σ₅= 143.79N/mm²、σ₆=141.92N/mm²；

Determine out-of-balance force suffered by each shaft tower；

ΔF₁=925.9N, Δ F₂=2142.7N, Δ F₃=5298.1N, Δ F₄=688.5N, Δ F₅=634.3N.

Step 4, relatively real-time stress value are uneven with the limit with the relation of horizontal limeit stress value and shaft tower out-of-balance force The relation of power, the present embodiment horizontal limeit stress value σ_limFor 108.8N, the design of each straight line pole can bear out-of-balance force Δ Fs =7377.6N.

Each shelves horizontal stress σ in the present embodiment_i>σ_lim, export each shelves wire red early warning；

In the present embodiment, each shaft tower out-of-balance force is respectively as follows: Δ F₁=12.55%, Δ F₂=29.04%, Δ F₃= 71.81%, Δ F₄=9.33%, Δ F₅=8.6%, wherein, the 3rd base straight line pole 0.6 Δ Fs < Δ F₃< 0.8 Δ Fs, output the 3 base straight line pole yellow early warning, other straight line pole not early warning.

Claims (3)

1. an icing transmission line of electricity weak link method for early warning, it is characterised in that comprise the following steps:

Step 1, determining weather information, ice covering thickness information and overhead transmission line details, described weather information specifically includes: real Shi Wendu t, highest temperature t_max, lowest temperature t_min, temperature on average t_avThe temperature on average t produced with icing_ice；Ice covering thickness is believed The ice covering thickness b of each shelves of the most continuous shelves of breath；The bullet that overhead transmission line details specifically include wire type, this wire type is corresponding Property coefficient E, sectional area A, outer diameter D, linear mass q, each shelves span l_i0, each shelves discrepancy in elevation h_i0, each shelves discrepancy in elevation angle beta_i0, each base The length lambda of suspension insulator on linear tension tower_i, vertical load G_i, stringing time temperature t₀, initial level should under stringing temperature Power σ₀₀；

Step 2, according to known weather information, determine initial level stress by ruling span method computation model, then by accurately Stress calculation model is the real-time stress value σ of each grade in determining strain insulator tower section_i；

Step 3, stress σ by each span inside conductor determined in step 2_i, determine suffered unbalanced tensile force Δ on each anchor support F_i；Unbalanced tensile force Δ F_iComputation model be:

△F_i=(σ_i+1-σ_i) A=F_i+1-F_i (i=1,2,…,n-1)

In formula: σ_i+1And σ_iBeing respectively i+1 shelves and the horizontal stress of i-th grade of electric wire, n is the number of anchor support；

A is wire cross-section area；

F_i+1And F_iIt is respectively i+1 shelves and the Horizontal Tension of i-th grade of electric wire；

△F_iThe unbalanced tensile force born in i-th base linear tension tower ice detachment is poor；

Step 4, by each span inside conductor stress σ_iWith its limit stress σ_limComparing, graduation carries out wire early warning；Will On each anchor support, unbalanced tensile force designs with it and can bear unbalanced tensile force Δ F_sComparing, graduation carries out anchor support not Equilibrant early warning.

A kind of icing transmission line of electricity weak link method for early warning, it is characterised in that described step 2, according to known weather information, determine initial level stress by ruling span method computation model, then by accurate Stress calculation mould Type is the real-time stress value σ of each grade in determining strain insulator tower section_i, specifically include following steps:

Step 2-1, determine limit stress σ of transmission line wire_lim；Formula used is:

In formula, T_bFor the calculating pull-off force of wire, A is wire cross-section area；

Step 2-2, determine and represent discrepancy in elevation angle beta_rWith ruling span l_r；Formula used is respectively as follows:

In formula, β_rWait to ask, for representing height difference angle, l_i0It is i-th grade of span, β_i0Being i-th grade of height difference angle, i is the positive integer from 1 to n, N is gear number；

In formula, l_rWait to ask, for ruling span, β_rFor representing height difference angle, l_i0It is i-th grade of span, β_i0Be i-th grade of height difference angle, i be from The positive integer of 1 to n, n is gear number；

Step 2-3, by ruling span method computation model, utilize temperature t when installing electric wiring₀With the parameter of transmission line wire, Determine highest temperature t_max, lowest temperature t_min, temperature on average t_avRespective stress value under three kinds of meteorological conditions, connects stress value most Nearly horizontal stress design load σ₀₀The meteorological condition corresponding to calculating state as the initial gas of accurate Stress calculation model as bar The final states meteorological condition calculated in part, and following step 2-5；Described ruling span method computation model is as follows:

In formula, numeral 1 represents initial meteorology, and numeral 2 represents end meteorology, and t is temperature, and α is that conductor temperature expands Coefficient, E is the coefficient of elasticity of transmission line wire, σ₀₁For initial state horizontal stress, σ₀₂For final states horizontal stress, l_γFor representing Span, β_γFor representing height difference angle, γ is ratio load, γ=q*g/A, and wherein q is conductor quality, and g is acceleration of gravity, A is wire cross-section area；

Step 2-4, again by ruling span method computation model, utilize temperature t when installing electric wiring₀, icing produce average air Temperature t_iceWith the parameter of transmission line wire, determine that the wire always ratio that different ice covering thickness is corresponding carries γ_bUnder the conditions of stress value, By stress value closest to limit σ_limThe meteorological condition corresponding to calculating state as the initial gas in following step 2-5 as bar Part；The wire always ratio that described different ice covering thickness is corresponding carries γ_bComputing formula is:

In formula, q is the unit mass of wire, and D is the external diameter of wire, b ice covering thickness, and A is wire cross-section area；

Step 2-5, utilize the final states meteorological condition described in step 2-3, the initial meteorological condition described in step 2-4, and set pole Limit stress σ_limFor initial stress values, third time uses ruling span method computation model, tries to achieve initial level stress value σ₀, and Using it as the initial level stress of accurate Stress calculation model；

Step 2-6, according to all known real-time weather conditions, each in using accurate Stress calculation model to try to achieve strain insulator tower section The real-time stress value σ of shelves_i；Described accurate Stress calculation model includes three below relational model:

(1) span increment Delta l_iWith horizontal stress σ_iBetween relational model:

σ in formula_iTo be evaluated, it is i-th grade and is t at temperature, is γ than carrying_iUnder electric wire horizontal stress；I from 1 to n is just Integer, n is gear number；

σ₀Initial level stress value；

l_i0I-th grade of span；

γ₀、γ_iThan carrying and ratio load after wire icing, γ before wire icing₀For q*g/A, γ_iFor q*g/A+0.027728 (b (b+D)/A), wherein q is conductor quality, and g is acceleration of gravity, and A is wire cross-section area, and b is that wire icing is thick Degree, D is wire diameter；

△l_iTo be evaluated, the l of i-th grade of span_i0Increment, specially i-th grade span is than stringing situation suspension insulator The increment of span during vertical position in being in；

△h_iTo be evaluated, i-th grade of discrepancy in elevation h_i0Increment, specially i-th grade two ends suspension insulator deflection aft hook Between discrepancy in elevation h_i0Variable quantity, the high left hitch point person h of right hitch point_i0And discrepancy in elevation angle beta_i0For on the occasion of；

t、t₀Temperature when being respectively real time temperature and stringing；

The α conductor temperature coefficient of expansion；

E wire coefficient of elasticity；

(2) i-th grades of discrepancy in elevation increment Delta h_iWith the i-th anchor support hitch point skew δ_iBetween relational model:

△ h in formula_iTo be evaluated, i-th grade of discrepancy in elevation h_i0Increment, i is the positive integer from 1 to n, and n is gear number；

δ_i、δ_i-1The horizontal range of hitch point skew on i-th grade of two ends i-th-1 anchor support, the δ of both end of which anchor support is 0；

Suspension insulator string length on each anchor support of λ, both end of which anchor support has also assumed that λ, but δ has been 0；

(3) i-th anchor support hitch point skew δ_iAnd σ between horizontal stress_iRelational model:

σ in formula_iTo be evaluated, it is i-th grade and is t at temperature, is γ than carrying_iUnder electric wire horizontal stress；I from 1 to n is just Integer, n is gear number；

δ_i——δ_i=δ_i-1+△l_i；

A wire cross-section area；

γ_iThan carrying after wire icing, γ_iFor q*g/A+0.03 (b (b+D)/A), wherein q is conductor quality, g For acceleration of gravity, A is wire cross-section area, and b is wire icing thickness, and D is wire diameter；

δ_iThe horizontal range of hitch point skew on i-th grade of two ends anchor support, the δ of both end of which anchor support is 0；

G_i, the vertical load of suspension insulator on each anchor support of λ and length, both end of which anchor support has also assumed that λ, but δ is 0；

l_i0I-th grade of span；

h_i0、h_(i+1)0I-th grade and the i+1 shelves discrepancy in elevation, during specially suspension insulator is in during vertical position, the i-th base is resistance to On tower, electric wire hitch point is to the discrepancy in elevation between adjacent anchor support i-th-1 and i+1 base hitch point, and large size anchor support is than small size anchor support High person h itself value on the occasion of, otherwise be negative value, scene records；

β_i0I-th grade of height difference angle.

A kind of icing transmission line of electricity weak link method for early warning, it is characterised in that institute in step 4 Stating the concrete numerical relation of wire early warning with corresponding advanced warning grade is:

The concrete numerical relation of described wire early warning with corresponding advanced warning grade is:

Work as σ_i< 50% σ_limTime, not early warning；

As 50% σ_lim≤σ_i≤ 70% σ_limTime, export i-th grade of wire yellow early warning；

As 70% σ_lim<σ_i< 85% σ_limTime, export i-th grade of orange early warning of wire；

Work as σ_i>=85% σ_limTime, export i-th grade of wire red early warning；

The concrete numerical relation of described anchor support out-of-balance force early warning with corresponding advanced warning grade is:

As Δ F_i≤ 0.6 Δ Fs, not early warning；

As 0.6 Δ Fs < Δ F_i< 0.8 Δ Fs exports the i-th base anchor support yellow early warning；

As 0.8 Δ Fs≤Δ F_i≤ 0.95 Δ Fs, exports the i-th orange early warning of base anchor support；

As Δ F_i> 0.95 Δ Fs, export the i-th base anchor support red early warning.