CN103441450A - Deicing method based on icing rolling on electric transmission line - Google Patents

Abstract

The invention discloses a deicing method based on an electric transmission line cable deicing robot. During deicing, the deicing robot moves on an electric transmission line cable so as to remove ice. The deicing method comprises the following steps of calculating the horizontal tension of each grade of cable on the electric transmission line so as to obtain the horizontal tension value of each grade during icing; comparing the horizontal tension values of all the grades so as to determine the grade with the maximum horizontal tension value, manually pulling a pulley to the cable at the grade with the maximum horizontal tension value, and stressing the pulley so as to enable a blade on the pulley to clear away the ice on the grade with the maximum tension value; determining the grade with the maximum tension value among the rest of grades by adopting a bubbling method, manually pulling the pulley to the cable at the grade with the maximum horizontal tension value among the rest of grades, stressing the pulley so as to clear way the ice on the grade with the maximum tension value till the ice on each grade of cable is completely removed. The deicing method is safe and can be used for reducing the unbalance tensile force of towers in a deicing process.

Description

A kind of de-icing method of scraping based on transmission line pulley spreading shovel

Technical field

What the present invention relates to is a kind of de-icing method, specifically a kind ofly is applicable to the de-icing method that transmission line pulley spreading shovel is scraped.

Background technology

Icing on transmission line and accumulated snow, often cause line tripping, broken string, the accidents such as bar, insulator arc-over.In 2008, Extreme Ice snow disaster evil occurred in the south China area, causes altogether the stoppage in transit that surpasses 36000 10kV and above power transmission line, more than 2000 35kV and above transformer station, and China's electrical network and national economy have been caused to great loss.

Since white the 1950's, countries in the world continue powerline ice-covering is studied, and explore the defence method of icing mechanism, icing formation condition, icing disaster etc.Current de-icing method mainly is divided into heating power de-icing method and mechanical deicing's method, and wherein mechanical deicing's method has cost low than the heating power de-icing method, simple to operate, and power consumption is few, the characteristics that efficiency is high.

By the pulley shovel technology of scraping of Canadian Manitoba hydroelectric board development, be a kind ofly by the terrestrial operation personnel, pull pulley to walk on the line and root out the technology of wire icing, use the de-icing method of this technology pulley spreading one-lick (icing tolling), pulley spreading one-lick has been used more than 50 year at Canadian Manitoba, is the current mechanical means of unique feasible removing ice of power transmission line.It consists of devices such as the glued board of pulley, pull rope and japanning or epoxy resin boards, and it is crooked that the power on pulley of being added in will enough allow wire produce, and like this, the stress of generation just can make ice break to come off.The great advantage of pulley one-lick is that effect is very fast, and does not need special equipment and expert, simple and easy to operate, consumes energy little, cheap, comparatively practical.

But in the research of this pulley spreading one-lick, the negative effect that also deicing of not to be noted pulley spreading one-lick order brings.In to icing disaster in 2008 in the analysis of the circuit of falling the tower, the out-of-balance force of finding the shaft tower two ends causes directly to fall tower and traction by shaft tower to fall tower be the major reason that causes falling tower on a large scale.When icing is more serious, the out-of-balance force of shaft tower both sides can surpass its design strength, causes the fault of falling the tower.When adopting the deicing of pulley spreading one-lick order, even powerline ice-covering is not very serious, the out-of-balance force of its design strength also may appear on shaft tower surpassing, this will cause the negative effect of order deicing.Therefore, in order to guarantee effective application of pulley spreading one-lick, the de-icing method that need to scrape the deicing method to this transmission line pulley spreading shovel is studied.

Summary of the invention

For above deficiency of the prior art, the object of the present invention is to provide a kind of safety deicing, reduce the de-icing method based on the transmission line cable deicing robot of shaft tower unbalanced tensile force in ice detachment, for achieving the above object, technical scheme of the present invention is: a kind of de-icing method of scraping based on transmission line pulley spreading shovel, during deicing, the workman pulls pulley to walk on transmission line and roots out wire icing, and it comprises the following steps:

A, rule of thumb formula, A, the cable Horizontal Tension of each grade on transmission line is calculated, each grade of Horizontal Tension value while drawing icing, comprise step: A1, scene obtain wire type, corresponding coefficient of elasticity E, sectional area A, the linear mass q of wire type that table look-up to obtain, each grade of span l _i0, each grade of discrepancy in elevation, height difference angle β _i0, the length lambda of suspension insulator on each base tangent tower _i(m) and by the suspension insulator model vertical load G that tables look-up to obtain _i(N), the temperature t when scene temperature meter measures deicing, wire icing thickness b, temperature t during stringing _o, each grade of horizontal stress σ under stringing temperature ₀;

A2, step 1, list span and change the relation of asking with wire stress:

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

σ in formula _i0---to be evaluated, be that the i shelves are t at temperature, are γ than carrying _iunder electric wire horizontal stress (N/mm ²);

σ ₀---each grade of horizontal stress under stringing temperature can check in or formula calculates by the stringing design drawing;

L _i0---each grade of span;

γ ₀, γ _ibefore-wire icing than carry and wire icing after than carrying, γ ₀for q*g/A, γ _ifor q*g/A+0.027728 (b (b+D)/A), wherein q is the wire linear mass, and g is acceleration of gravity, and A is sectional area of wire, and b is wire icing thickness, and D is wire diameter;

Δ l _i---be i shelves span than stringing situation suspension insulator in the increment of span while hanging down position, unit is m;

Δ h _i---be discrepancy in elevation h between the suspension insulator deflection aft hook of i shelves two ends _i0variable quantity, the m of unit, right hitch point is height difference angle β during higher than left hitch point _i0for on the occasion of;

T, t ₀---temperature when temperature and stringing during deicing that the scene of being respectively records, t ₀generally get 25 ℃;

α---the wire coefficient of expansion, unit is 1/ ℃, according to wire type, table look-up;

Step 2, list the i shelves discrepancy in elevation and change the relational expression of asking with the skew of i base tower hitch point:

${\mathrm{\Δh}}_i=(\mathrm{\λ}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2})-(\mathrm{\λ}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_{i-1}}^2})=\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_{i-1}}^2}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2}\left(m\right)$ (formula 2)

Δ h in formula _i---to be evaluated, i shelves discrepancy in elevation h _i0increment

δ _i, δ _i-1---to be evaluated, the same with the growth value of span, be respectively the horizontal range that on i shelves and i-l shelves, hitch point is offset, wherein on the strain tower of two ends, the horizontal distance delta of hitch point skew is 0;

λ---the suspension insulator string length on each shaft tower, wherein also suppose on the strain tower of two ends that it is also λ that its length of suspension insulator is arranged;

Step 3, list the relation equation between suspension insulator deflection and wire stress:

$\begin{array}{c}{\mathrm{\σ}}_{(i+1)o}=\{(\frac{G_i}{2A}+\frac{{\mathrm{\γ}}_i{l}_{i0}}{2\cos {\mathrm{\β}}_{i0}}+\frac{{\mathrm{\γ}}_{(i+1)}{l}_{(i+1)0}}{2\cos {\mathrm{\β}}_{(i+1)0}}+\frac{{\mathrm{\σ}}_{\mathrm{io}}{h}_{i0}}{l_{i0}})+\frac{{\mathrm{\σ}}_{\mathrm{io}}}{{\mathrm{\δ}}_i}\sqrt{{{\mathrm{\λ}}_i}^2-{{\mathrm{\δ}}_i}^2}\}\\ \÷(\frac{1}{{\mathrm{\δ}}_i}\sqrt{{{\mathrm{\λ}}_i}^2-{{\mathrm{\δ}}_i}^2}+\frac{h_{(i+1)0}}{l_{(i+1)0}})(N/{\mathrm{mm}}^2)\end{array}$ (formula 3)

δ in formula _i---δ _i=δ _i-1+ Δ l _i, unit is m;

A---wire coefficient of elasticity and sectional area, according to wire type, table look-up;

γ _i---after wire icing, ratio carries, γ _ifor q*g/A+0.027728 (b (b+D)/A), wherein q is the wire linear mass, and g is acceleration of gravity, and A is sectional area of wire, and b is wire icing thickness, and D is wire diameter;

δ _i---to be evaluated, the same with the growth value of span, the horizontal range of hitch point skew on i shelves two end group towers, wherein the δ of two ends strain tower is 0;

Gi, λ---vertical load and the length of the suspension insulator on each shaft tower, wherein also suppose on the strain tower of two ends that it is also λ that its length of suspension insulator is arranged;

L _i0---each grade of span;

H _i0, h _{(i+1) 0}---suspension insulator all in while hanging down position, be respectively that on i base tangent tower, the electric wire hitch point is to the discrepancy in elevation between adjacent tower i-1 and i+1 base hitch point, unit is m, large size than small size tower height person h value itself be on the occasion of, otherwise be negative value;

β _i0---each grade of height difference angle;

Step 4, formula l formula 2 formulas 3 are formed to an equation group, total 3n equation, have △ l _i, Δ h _i, σ _i0be total to 3n unknown number, factorization solves, by each grade of horizontal stress σ drawn _i0be multiplied by sectional area of wire and be required each grade of Horizontal Tension;

In the present embodiment, preferably adopt software as matlab, the cable Horizontal Tension of each grade on transmission line to be calculated, each grade of Horizontal Tension value while drawing icing;

B, each grade of Horizontal Tension value obtained in steps A compared, draw a grade of Horizontal Tension value maximum, the workman pulls pulley to move to the cable place of maximum one grade of Horizontal Tension value, to afterburning on pulley and dispose the ice of maximum one grade of this Horizontal Tension value, jumps to step C;

C, employing bubbling method draw one grade maximum in residue shelves Horizontal Tension value, the workman pulls pulley to move to the cable place of maximum one grade of Horizontal Tension value in residue shelves, to afterburning on pulley and dispose the ice of maximum one grade of this Horizontal Tension value, repeating step C, until the icing of each grade of wire is all removed.

Further, described pulley spreading shovel is scraped glued board or the epoxy resin board that deicer comprises pull rope, japanning, and it is commercially available prod that its middle pulley spreading shovel is scraped deicer.

Further, described transmission line is continuously the shelves circuit.

Advantage of the present invention and beneficial effect are as follows:

By adjusting the deicing order, at first one grade of circuit of Horizontal Tension maximum carried out to deicing, avoid the excessive problem of shaft tower unbalanced tensile force can only a part of deicing caused because of the deicing of circuit robot.First remove between shelves wire stress relatively large, between shelves, the electric wire Horizontal Tension is large, effectively reduces in ice detachment the maximum horizontal tension force that shaft tower runs into, and avoids the improper consequence such as bar of bringing down of deicing.

The accompanying drawing explanation

Fig. 1 preferred embodiment of the present invention de-icing method flow chart;

Fig. 2 is the schematic diagram that the pulley shovel is scraped device;

Fig. 3 is the schematic diagram of computing electric power line.

Embodiment

The embodiment that provides an indefiniteness below in conjunction with accompanying drawing is further elaborated invention.

In engineering, the pulley one-lick is current unique feasible mechanical deicing's method, by the movable fixture on ground staff's straighforward operation circuit, scrape off line ice coating by the steel blade on device, but during because of the deicing of use pulley one-lick, each grade of circuit deicing simultaneously, will produce very large unbalanced tensile force between each grade of shelves continuously poor, to such an extent as to during the poor excessive design limit that reaches shaft tower of unbalanced tensile force, will make the shaft tower distortion of collapsing, not only effectively deicing, also can cause second accident.Therefore, the feature that the inventor can only a deicing for every grade of circuit of this pulley one-lick, proposed corresponding de-icing method.

Its de-icing method comprises the following steps:

A, the cable Horizontal Tension of each grade on transmission line is calculated to each grade of Horizontal Tension value while drawing icing;

B, each grade of Horizontal Tension value obtained in steps A compared, draw a grade of Horizontal Tension value maximum, the workman pulls pulley to move to the cable place of maximum one grade of Horizontal Tension value, to afterburning on pulley and allow blade on pulley dispose the ice of maximum one grade of this Horizontal Tension value, jump to step C;

C, employing bubbling method draw one grade maximum in residue shelves Horizontal Tension value, the workman pulls pulley to move to the cable place of maximum one grade of Horizontal Tension value in residue shelves, to afterburning on pulley and dispose the ice of maximum one grade of this Horizontal Tension value, repeating step C, until the icing of each grade of wire is all removed.

Preferably, described pulley spreading shovel is scraped glued board or the epoxy resin board that deicer comprises pull rope, japanning.

Preferably, described transmission line is continuously the shelves circuit.

Wherein the first step need to be carried out the circuit Mechanics Calculation to overhead transmission line, the size of each grade of Horizontal Tension while calculating icing, and the 3rd step need to calculate the size that a certain shelves removed ice each grade of circuit Horizontal Tension afterwards.And when the span of continuous shelves and height difference angle differs greatly or shelves between electric wire than carrying a difference, be that each grade of icing is when inhomogeneous, between each grade, the horizontal stress of electric wire may have marked difference, now just can not adopt ruling span method commonly used to remove the wire stress of each grade of approximate calculation.For sag in the drift angle that checks the unbalanced tensile force that may occur on the linear pattern shaft tower or suspension string and shelves etc., need to adopt accurate computational methods solve each grade of different wire stress value in strain section.

1, the relational expression between span variation and wire stress

When setting up continuous shelves electric wire, for considering just percentage elongation ε of compensation _jand each grade of horizontal stress after the tension electric wire is made as σ ₀, and establish vertical ratio and carry as γ ₀, stringing temperature is t ₀, suspension string in the hang down vertical ratio of electric wire of position, i shelves carry and become γ _ior while being attached with other inhomogeneous loads, the electric wire horizontal stress becomes σ _i0, span is than the l in stringing situation _i0increase Δ l _i(be l _i=l _i0+ Δ l _i), height difference angle becomes β _i, suppose just elongation epsilon _jall emit.Write out the original line length (σ of i shelves under this state _i0=0, t=0 ℃, ε _j=0 o'clock) be

$\begin{array}{c}{L}_{i0}=[\frac{l_{i0}}{\cos {\mathrm{\β}}_{i0}}+{\mathrm{\Δl}}_i\cos {\mathrm{\β}}_{i0}+{\mathrm{\Δh}}_i\sin {\mathrm{\β}}_{i0}+\frac{{{\mathrm{\γ}}_i}^2{l_{i0}}^3\cos {\mathrm{\β}}_{i0}}{{{24\mathrm{\σ}}_{i0}}^2}(1+\frac{{3\mathrm{\Δl}}_i}{l_{i0}})]\\ -\frac{l_{i0}}{\cos {\mathrm{\β}}_{i0}}\left(\frac{{\mathrm{\σ}}_{i0}}{E\cos {\mathrm{\β}}_{i0}}\right)-\frac{l_{i0}}{\cos {\mathrm{\β}}_{i0}}(\mathrm{\αt}+{\mathrm{\ϵ}}_j)\end{array}$ (formula 1)

Original line length during i shelves stringing is

$L_{i0}\≈(\frac{l_{i0}}{\cos {\mathrm{\β}}_{i0}}+\frac{{{\mathrm{\γ}}_0}^2{l_{i0}}^3\cos {\mathrm{\β}}_{i0}}{{{24\mathrm{\σ}}_0}^2})-\frac{l_{i0}}{\cos {\mathrm{\β}}_{i0}}\left(\frac{{\mathrm{\σ}}_{i0}}{E\cos {\mathrm{\β}}_{i0}}\right)-\frac{l_{i0}{\mathrm{\αt}}_0}{\cos {\mathrm{\β}}_{i0}}$ (formula 2)

Utilize the same principle of above two states original line appearance, can write out i shelves span increment Delta l _iequation be

$\begin{array}{c}{\mathrm{\Δl}}_i\≈\frac{l_{i0}}{\cos {{\mathrm{\β}}_{i0}}^2(1+\frac{{{\mathrm{\γ}}_i}^2{l_{i0}}^2}{8{{\mathrm{\σ}}_{i0}}^2})}\\ \×\left\{\frac{{l_{i0}}^2\cos {{\mathrm{\β}}_{i0}}^2}{24}\right[{\left(\frac{{\mathrm{\γ}}_0}{{\mathrm{\σ}}_0}\right)}^2-{\left(\frac{{\mathrm{\γ}}_i}{{\mathrm{\σ}}_{i0}}\right)}^2]+\left(\frac{{\mathrm{\σ}}_{i0}-{\mathrm{\σ}}_0}{E\cos {\mathrm{\β}}_{i0}}\right)+\mathrm{\α}(t-t_0+\frac{{\mathrm{\ϵ}}_j}{\mathrm{\α}})-\frac{{\mathrm{\Δh}}_i}{{2l}_{i0}}\cos {{\mathrm{\β}}_{i0}}^2\}\end{array}$ (formula 3)

In formula

σ _i0---be that the i shelves are t at temperature, are γ than carrying _iunder electric wire horizontal stress (N/mm ²);

Δ l _i---be i shelves span than stringing situation suspension string in the increment (m) of span while hanging down position, Δ l when span shortens _ithis is as negative value;

Δ h _i---be discrepancy in elevation h between the suspension string deflection aft hook of i shelves two ends _i0and β _i0for on the occasion of.

Utilize above formula can list n equation, wherein σ of n gear number _i0, Δ l _i, Δ h _itotal 3n unknown number.Still need and be listed as again 2n equation, ∑ Δ l is wherein arranged _i=0 and n the change of elevation Δ h _iand the relation equation of the relation equation between the skew of two ends hitch point and the skew of n-1 base straight line pole hitch point and two lateral stresses.Total 3n equation.

2, the relational expression between the variation of the i shelves discrepancy in elevation and the skew of i base tower hitch point

Can write out i shelves discrepancy in elevation changes delta h _iand the pass on the shaft tower of two ends between hitch point skew δ is

${\mathrm{\Δh}}_{i0}=(\mathrm{\λ}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2})-(\mathrm{\λ}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_{i-1}}^2})=\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_{i-1}}^2}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2}\left(m\right)$ (formula 4)

Δ h in formula _i0---i shelves discrepancy in elevation h _i0increment

δ _i, δ _i-1---the horizontal range of hitch point skew on i shelves two ends i-1 Ji Ta, wherein the δ of two ends strain tower is 0;

λ---the suspension insulator string length (m) on each shaft tower, wherein on the strain tower of two ends, also supposes λ is arranged, but δ is 0.

Utilize above formula can list n equation.

3, the relation equation between suspension string deflection and wire stress

Occur that in the suspension string both sides uneven Horizontal Tension is poor due to each grade of electric wire horizontal stress possibility difference under state to be asked, it makes suspension string produce deflection.

Suppose that the rigidity that the pendulous string isolator string is evenly load is directly excellent, on i base tangent tower, the vertical load of suspension string is G _i(N), length is λ _i(m), lower end is acting on the vertical load W of electric wire _iand the poor A (σ of horizontal unbalanced tensile force (N) _{(i+1) 0}-σ _i0), wherein A is the electric wire sectional area, σ _{(i+1) 0}and σ _i0be respectively the electric wire horizontal stress in i+1 shelves and i shelves.Can write out the relational expression between suspension string end offset distance and both sides electric wire horizontal stress on i base tangent tower according to the force balance condition is (N/mm ²).Can write out suspension string end offset distance δ on i base tangent tower according to the force balance condition _i(m) and the relational expression between the electric wire horizontal stress of both sides be

(formula 5)

$\frac{W_i}{A}\≈(\frac{{\mathrm{\γ}}_i{l}_{i0}}{2\cos {\mathrm{\β}}_{i0}}+\frac{{\mathrm{\σ}}_{\mathrm{io}}{h}_{i0}}{l_{i0}})+(\frac{{\mathrm{\γ}}_{(i+1)}{l}_{(i+1)0}}{2\cos {\mathrm{\β}}_{(i+1)0}}+\frac{{\mathrm{\σ}}_{(i+1)o}{h}_{(i+1)0}}{l_{(i+1)0}})(N/{\mathrm{mm}}^2)$ (formula 6)

Bring formula 6 into formula 5, arrange and obtain explicit form:

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

(formula 7)

δ in formula _i=δ _i-1+ Δ l _i(m) (formula 8)

H _i0, h _{(i+1) 0}---suspension string all in while hanging down position, be respectively on i base tangent tower the electric wire hitch point to the discrepancy in elevation (m) between adjacent tower i-1 and i+1 base hitch point, large size than small size tower height person h value itself be on the occasion of, otherwise be negative value.

4, computing

If in strain section, the n shelves are arranged, n-1 base tangent tower is arranged, utilize formula 7 can list the relation equation of n-1 suspension string skew and two lateral stresses.

List altogether 3n equation, wherein Δ l by above-mentioned one to three _i, Δ h _i, σ _i03n unknown number can be solved altogether.Comparatively directly method for solving is to utilize above-mentioned formula 3, formula 4, formula 7 to program to try to gather to solve.From the 1st grade that numbers, computing in the following order:

(1) establish Δ l ₁=δ ₁, δ ₀=0 substitution formula 4 obtains Δ h ₁, again by Δ h ₁, Δ l ₁substitution formula 3 obtains σ ₁₀

(2) by σ ₁₀, δ ₁substitution formula 7 obtains σ ₂₀

(3) by σ ₂₀, establish Δ h ₂=0 substitution formula 3 obtains Δ l ₂', again by Δ l ₂', Δ l ₁substitution formula again 8 obtains δ ₂', again by δ ₂', δ ₁substitution formula again 4 obtains Δ h ₂'

(4) by σ ₂₀, Δ h ₂' substitution formula again 3 obtains Δ l ₂", again by Δ l ₂", Δ l ₁substitution formula again 8 obtains δ ₂", again by δ ₂", δ ₁substitution formula again 4 obtains Δ h ₂"

Step (4) iterates until Δ l ₂, δ ₂, Δ h ₂be required (also can adopt more effective convenient method iteration) without significant change.

(5) by δ _i0, Δ h _i=0 substitution formula 3, obtain Δ l _i', again by Δ l _i', δ _i-1substitution formula 8 obtains δ _i', again by δ _i', δ _i-1substitution formula 4 obtains Δ h _i'

(6) what by step (5), started establishes Δ h _i=0 is changed to Δ h _i=Δ h _i' repeating step (5) iterates until Δ l _i, Δ h _i, δ _iwithout significant change, be required.Note in iteration avoiding occurring endless loop.

(7) by δ _n-1, σ _{(n-1) 0}substitution formula 4 obtains σ _n0, again by δ _n-1, δ _n=0 substitution formula 4 obtains Δ h _n, again by Δ h _n, σ _n0substitution formula 4 obtains Δ l _n, then by Δ l _n, δ _n-1substitution formula 8 obtains δ _n≈ 0

Be solve, otherwise should restart to establish Δ l ₁deng repetitive operation.The δ calculated _ibe the electric wire horizontal stress of each grade.

Below in conjunction with subordinate list, preferred embodiment is elaborated, should be emphasized that, following explanation is only exemplary, rather than in order to limit the scope of the invention and to apply.

To a mountain area pin insulator circuit, wire adopts LGJ-240/30 shaped steel core aluminum stranded wire, and sectional area is 275.96mm2, coefficient of elasticity E=73000N/mm2, certain strain section length of wire is 1.26km, and totally seven grades, span from left to right is respectively 50m, 200m, 150m, 300m, 200m, 250m, 110m.The discrepancy in elevation from left to right is respectively 10m, 30m, and 35m, 60m, 0m, 50m, 20m, on each base tangent tower, the vertical load of suspension insulator is G _i(N)=2800N, length are λ _i(m)=4.8m, wire deadweight force rate is carried γ ₀=0.03277N/ (mm ²m), ignore just percentage elongation of wire.

Adopt isostension method stringing in strain section, under the stringing meteorological condition, the straight line pole both sides are without unbalanced tensile force, when differing from the stringing meteorological condition, if the span difference there will be unbalanced tensile force poor.If wire icing 10mm is thick, wind speed is 10m/s, temperature is-5 ℃, and stringing temperature is 15 ℃, and under stringing temperature, each grade of horizontal stress is 41.38N/mm ².

One, with the deicing of pulley spreading one-lick, do not use this de-icing method, directly the step of order deicing is as follows:

The first step, the size of each grade of Horizontal Tension while calculating icing;

Apply above-mentioned icing stress rigorous method, with matlab, by above-mentioned calculating and iterative step, program and iterate, while calculating icing 10mm, each grade of horizontal stress during deicing not, each grade of Horizontal Tension, and the unbalanced tensile force on each straight line pole is poor.Obtain a result as table 1.

Table 1

During icing 10mm, the initial unbalance Tension Difference on straight line pole is 5684.8N to the maximum.

Second step, remove first grade, and first grade of ratio carries and become electric wire deadweight force rate and carry, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 8000.1N;

The 3rd step, remove second gear, and second gear ratio year becomes electric wire deadweight force rate and carries, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 6774.8N;

The 4th step, remove third gear, and third gear ratio year becomes electric wire deadweight force rate and carries, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 9415.8N;

The 5th step, remove fourth speed, and fourth speed ratio year becomes electric wire deadweight force rate and carries, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 8000.1N;

The 6th step, remove the 5th grade, and the 5th grade of ratio carries and become electric wire deadweight force rate and carry, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 8833.5N;

The 7th step, remove the 6th grade, and the 6th grade of ratio carries and become electric wire deadweight force rate and carry, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 5378.5N;

The 8th step, remove the 7th grade, and the 7th grade of ratio carries and become electric wire deadweight force rate and carry, and the maximum unbalanced tensile force on the calculated line shaft tower is poor is 0N;

In the order ice detachment, the unbalanced tensile force on each stage straight line pole is poor is 9415.8N, as shown in table 2.

Two, use the deicing of pulley spreading one-lick, can only one grade of one grade of deicing, use this de-icing method, its deicing step is as follows:

The first step, the size of each grade of Horizontal Tension while applying above-mentioned rigorous method calculating icing, obtaining each grade of Horizontal Tension is respectively 13734.5N, 19419.3N, 18194.0N, 20835.0N, 19419.3N, 20252.7N, 16797.7N from the 1st grade to the 7th grade;

Second step, maximum horizontal tension force is 20835.0N, is the 4th grade, removes the ice of the 4th grade;

The 3rd step, the substitution rigorous method recalculates the size of each grade of Horizontal Tension;

The 4th step, repeat second step and the 3rd step, until the icing of each grade of wire is all removed.

Each grade of Horizontal Tension of above each step is as shown in table 3,

Table 3

Each shaft tower out-of-balance force is as shown in table 4.

Table 4

As shown in Table 4, scrape the deicing method for pulley spreading shovel that can only one grade of one grade of deicing, while using this method deicing, in ice detachment, the shaft tower maximal unbalanced force is only 8000.1N, much smaller than the maximal unbalanced force of order de-icing method 9419.8N, avoided to a certain extent the very large unbalance power because of the adjacent span generation of Disadvantageous combination.So being transmission line pulley spreading shovel, de-icing method scrapes the optimum de-icing method of deicing method.

Above embodiment is interpreted as only for the present invention is described, is not used in and limits the scope of the invention.After the content of having read record of the present invention, the technical staff can make various changes or modifications the present invention, and these equivalences change and modification falls into the scope of the claims in the present invention equally.

Claims (3)

1. one kind is shoveled the de-icing method of scraping based on the spreading of transmission line pulley, and during deicing, the workman pulls pulley to walk on transmission line and roots out wire icing, it is characterized in that comprising the following steps:

A, the cable Horizontal Tension of each grade on transmission line is calculated, each grade of Horizontal Tension value while drawing icing, comprise step: A1, scene obtain wire type, corresponding coefficient of elasticity E, sectional area A, the linear mass q of wire type that table look-up to obtain, each grade of span l _i0, each grade of discrepancy in elevation, height difference angle β _i0, the length lambda of suspension insulator on each base tangent tower _i(m) and by the suspension insulator model vertical load G that tables look-up to obtain _i(N), the temperature t when scene temperature meter measures deicing, wire icing thickness b, temperature t during stringing _o, each grade of horizontal stress σ under stringing temperature ₀;

A2, step 1, list that span changes and wire stress between relation:

$\begin{array}{c}{\mathrm{\Δl}}_i\≈\frac{l_{\mathrm{io}}}{{{\cos \mathrm{\β}}_{i0}}^2(1+\frac{{{\mathrm{\γ}}_i}^2{l_{i0}}^2}{8{{\mathrm{\σ}}_{i0}}^2})}\\ \×\left\{\frac{{l_{i0}}^2\cos {{\mathrm{\β}}_{i0}}^2}{24}\right[{\left(\frac{{\mathrm{\γ}}_0}{{\mathrm{\σ}}_0}\right)}^2-{\left(\frac{{\mathrm{\γ}}_i}{{\mathrm{\σ}}_{i0}}\right)}^2]+\left(\frac{{\mathrm{\σ}}_{i0}-{\mathrm{\σ}}_0}{E\cos {\mathrm{\β}}_{i0}}\right)+\mathrm{\α}(t-t_0+\frac{{\mathrm{\ϵ}}_j}{\mathrm{\α}})-\frac{{\mathrm{\Δh}}_i}{{2l}_{i0}}\cos {{\mathrm{\β}}_{i0}}^2\}\end{array}$ (formula 1)

σ in formula _i0---to be evaluated, be that the i shelves are t at temperature, are γ than carrying _iunder electric wire horizontal stress (N/mm ²);

σ ₀---each grade of horizontal stress under stringing temperature can check in or formula calculates by the stringing design drawing;

L _i0---each grade of span;

γ ₀, γ _ibefore-wire icing than carry and wire icing after than carrying, γ ₀for q*g/A, γ _ifor q*g/A+0.027728 (b (b+D)/A), wherein q is the wire linear mass, and g is acceleration of gravity, and A is sectional area of wire, and b is wire icing thickness, and D is wire diameter;

Δ l _i---be i shelves span than stringing situation suspension insulator in the increment of span while hanging down position, unit is m;

Δ h _i---be that i shelves two ends suspension insulator deflection aft hook is asked discrepancy in elevation h _i0variable quantity, the m of unit, right hitch point is height difference angle β during higher than left hitch point _i0for on the occasion of;

T, t ₀---temperature when temperature and stringing during deicing that the scene of being respectively records, t ₀generally get 25 ℃;

α---the wire coefficient of expansion, unit is l/ ℃, according to wire type, table look-up;

Step 2, list the i shelves discrepancy in elevation and change the relational expression between being offset with i base tower hitch point:

$\mathrm{\Δ}{h}_i=(\mathrm{\λ}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2})-(\mathrm{\λ}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\β}}_{i-1}}^2})=\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\β}}_{i-1}}^2}-\sqrt{{\mathrm{\λ}}^2-{{\mathrm{\δ}}_i}^2}\left(m\right)$ (formula 2)

Δ h in formula _i---to be evaluated, i shelves discrepancy in elevation h _i0increment

δ _i, δ _i-1---to be evaluated, the same with the growth value of span, be respectively the horizontal range that on i shelves and i-1 shelves, hitch point is offset, wherein on the strain tower of two ends, the horizontal distance delta of hitch point skew is 0;

λ---the suspension insulator string length on each shaft tower, wherein also suppose on the strain tower of two ends that it is λ that its length of suspension insulator is arranged;

Step 3, list the relation equation between suspension insulator deflection and wire stress:

$\begin{array}{c}{\mathrm{\σ}}_{(i+1)o}=\{(\frac{G_i}{2A}+\frac{{\mathrm{\γ}}_i{l}_{i0}}{2\cos {\mathrm{\β}}_{i0}}+\frac{{\mathrm{\γ}}_{(i+1)}{l}_{(i+1)0}}{2\cos {\mathrm{\β}}_{(i+1)0}}+\frac{{\mathrm{\σ}}_{\mathrm{io}}{h}_{i0}}{l_{i0}})+\frac{{\mathrm{\σ}}_{\mathrm{io}}}{{\mathrm{\δ}}_i}\sqrt{{{\mathrm{\λ}}_i}^2-{{\mathrm{\δ}}_i}^2}\}\\ \÷(\frac{1}{{\mathrm{\δ}}_i}\sqrt{{{\mathrm{\λ}}_i}^2-{{\mathrm{\δ}}_i}^2}+\frac{h_{(i+1)0}}{l_{(i+1)0}})(N/{\mathrm{mm}}^2)\end{array}$ (formula 3)

δ in formula _i---δ _i=δ _i-1+ Δ l _i, unit is m;

A---wire coefficient of elasticity and sectional area, according to wire type, table look-up;

γ _i---after wire icing, ratio carries, γ _ifor q*g/A+0.027728 (b (b+D)/A), wherein q is the wire linear mass, and g is acceleration of gravity, and A is sectional area of wire, and b is wire icing thickness, and D is wire diameter;

δ _i---to be evaluated, the same with the growth value of span, the horizontal range of hitch point skew on i shelves two end group towers, wherein the δ of two ends strain tower is 0;

Gi, λ---vertical load and the length of the suspension insulator on each shaft tower, wherein also suppose on the strain tower of two ends that it is also λ that its length of suspension insulator is arranged;

L _i0---each grade of span;

H _i0, h _{(i+1) 0}---suspension insulator all in while hanging down position, be respectively that on i base tangent tower, the electric wire hitch point is to the discrepancy in elevation between adjacent tower i-1 and i+1 base hitch point, unit is m, large size than small size tower height person h value itself be on the occasion of, otherwise be negative value;

β _i0---each grade of height difference angle;

Step 4, formula 1 formula 2 formulas 3 are formed to an equation group, total 3n equation, have Δ l _i, Δ h _i, σ _i0be total to 3n unknown number, factorization solves, by each grade of horizontal stress σ drawn _i0be multiplied by sectional area of wire and be required each grade of Horizontal Tension;

B, each grade of Horizontal Tension value obtained in steps A compared, draw a grade of Horizontal Tension value maximum, the workman pulls pulley to move to the cable place of maximum one grade of Horizontal Tension value, to afterburning on pulley and allow blade on pulley dispose the ice of maximum one grade of this Horizontal Tension value, jump to step c;

C, employing bubbling method draw one grade maximum in residue shelves Horizontal Tension value, the workman pulls pulley to move to the cable place of maximum one grade of Horizontal Tension value in residue shelves, to afterburning on pulley and dispose the ice of maximum one grade of this Horizontal Tension value, repeating step C, until the icing of each grade of wire is all removed.

2. the de-icing method of scraping based on transmission line pulley spreading shovel according to claim 1, it is characterized in that: described pulley spreading shovel is scraped glued board or the epoxy resin board that deicer comprises pull rope, japanning.

3. the de-icing method of scraping based on transmission line pulley spreading shovel according to claim 1 is characterized in that: described transmission line is shelves circuit continuously.

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