CN103246805B - A kind of method of estimation for becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line - Google Patents

Abstract

The invention discloses a kind of method of estimation for becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line, comprising: (1) is asked for the maximum wind load of reality of circuit and set up its Normal probability distribution; (2) acquisition history wind load extreme value sample is calculated; (3) generalized extreme value distribution of actual wind load is set up; (4) by interference surface area method estimation of line time become stoppage in transit probability.The present invention according to the change of strong wind parameter, in conjunction with the wind load design level of overhead transmission line, performance analysis transmission line of electricity time become stoppage in transit probability, provide important theoretical decision-making foundation for electric system disaster prevention sexual behavior; Except considering the impact of short-term strong wind disaster, the present invention also considers that overhead transmission line is exposed to the fatigue caused under each extraneous rugged surroundings and loses factor in long service, can under the reflection strong wind disaster of objective overhead transmission line time become stoppage in transit probability.

Description

A kind of method of estimation for becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line

Technical field

The invention belongs to Study of Risk Evaluation Analysis for Power System technical field, being specifically related to a kind of method of estimation for becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line.

Background technology

In order to improve the level of safe operation of power system, the accuracy of Study of Risk Evaluation Analysis for Power System must be improved.Overhead transmission line is as element huge in electric system, and its reliability data can produce material impact to the result that system risk is assessed.And overhead power transmission line pole tower height, span is large, is easily subject to the impact of external environment, and along with Global climate change aggravation, strong wind disaster occurs more and more frequent.The overhead transmission line trip accident caused by the effect of strong wind disaster brings great risk can to the safe and stable operation of electric system, causes huge economic loss, and needs a large amount of fund of cost and time to repair.How scientifically and rationally so the overhead transmission line reliability level of analysis and evaluation under strong wind disaster, thus assess the operational reliability level of electrical network more accurately, be a problem with realistic meaning.

When strong wind disaster occurs, huge wind-force causes the reason of overhead transmission line fault to be, overhead transmission line itself can bear huge blast, causes wire significantly to swing, and finally because wind-force exceedes its physical strength, causes fault.Meanwhile, at the long term of strong wind, easily there is fatigue and lose in overhead transmission line, and produce accumulative effect, and the overhead transmission line making Years Of Service long, more easily by large wind effect, causes fault of stop.

In overhead transmission line outage model under traditional consideration strong wind disaster class weather, generally adopt statistical model, typically have homing method and bayes method.When homing method calculates strong wind disaster, the general process of overhead transmission line stoppage in transit parameter is: (1), according to historical data, sets up the regression model between each parameter when overhead transmission line fault and strong wind occur; (2) obtain the predicting condition of following strong wind weather, obtain time dependent related data; (3) the overhead transmission line failure condition under utilizing regression model to estimate following strong wind weather; Rule is found out from the strong wind parameter of accumulating over a long period of time and outage data, and for calculating instantly or the stoppage in transit probability of overhead transmission line in future or outage rate.Bayes method employing conditional probability table maps the relation between overhead transmission line outage rate and hazard weather.

From Long Significance, above-mentioned two kinds of existing methods have certain universal law, but have ignored the change of strong wind parameter, and the parameter of overhead transmission line itself is to the Real Time Effect of circuit reliability.Meanwhile, strong wind disaster class weather has regionality, and the electrical network in not all region has a large amount of historical statistical datas can supply to utilize; Therefore said method cannot under objective reflection strong wind disaster overhead transmission line time become stoppage in transit probability.

Summary of the invention

For the above-mentioned technical matters existing for prior art, the invention provides a kind of method of estimation for becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line, can under the reflection strong wind disaster of objective overhead transmission line time become stoppage in transit probability, provide important theoretical decision-making foundation for electric system disaster prevention sexual behavior.

For the method for estimation becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line, comprise the steps:

(1) according to the active time of overhead transmission line to be assessed, determine that the fatigue of overhead transmission line loses coefficient, and then lose coefficient calculations according to described fatigue and go out the maximum wind load of reality of overhead transmission line and the Normal probability distribution set up about the actual maximum wind load of overhead transmission line;

(2) determine current time before n time period and the sample frequency of each time period;

For any time period, calculate the actual wind load of each sampling instant overhead transmission line in this time period, and get the wind load extreme value of maximal value as this time period overhead transmission line of the corresponding actual wind load of each sampling instant in this time period;

Travel through each time period according to this, obtain n wind load extreme value corresponding to n time period;

(3) build the extreme value sample sequence be made up of n wind load extreme value, according to described extreme value sample sequence by maximum likelihood estimate, simulate the generalized extreme value distribution about the actual wind load of overhead transmission line;

(4) according to described Normal probability distribution and generalized extreme value distribution, by Stress strength interference area-method estimate current time overhead transmission line time become stoppage in transit probability.

In described step (1), the fatigue according to following standard determination overhead transmission line loses coefficient:

If overhead transmission line is in steady operation period, its fatigue loses coefficient ζ=1;

If overhead transmission line is in the loss phase, its fatigue is lost coefficient ζ and is tried to achieve according to following formula:

$\mathrm{\ζ}={\mathrm{\ζ}}_2{\left(\frac{t}{\mathrm{\α}}\right)}^{log\left({\mathrm{\β}}^{\frac{1}{\mathrm{\β}-1}}\right){\mathrm{\ζ}}_2}$

Wherein: α and β is respectively scale parameter and the form parameter of overhead transmission line, ζ ₂for losing coefficient with reference to fatigue.

Described reference fatigue loses coefficient ζ ₂tried to achieve by following process:

First, the actual maximum wind load W of reference of overhead transmission line is gone out according to following formulae discovery _c:

W _c＝6.25×10 ^-4α _cμ _cβ _cdL(Kv _c) ²(sinθ _c) ²

Wherein: α _cfor the wind evil attacking lung of overhead transmission line, μ _cfor the Shape Coefficient of overhead transmission line, β _cfor the wind of overhead transmission line carries regulation coefficient, d is the external diameter of overhead transmission line, the horizontal span of two shaft towers that L connects for overhead transmission line, the wind speed height change factor that K is highly corresponding residing for overhead transmission line; v _cfor overhead transmission line location is when the annual mean wind speed in the previous year, θ _cfor overhead transmission line location is when the annual wind direction in the previous year and the angle between overhead transmission line axis;

Then, according to formula ζ ₂=W _c/ W _ecalculate and lose coefficient ζ with reference to fatigue ₂; Wherein, W _efor the specified maximum wind load (parameter of dispatching from the factory of circuit) of overhead transmission line.

In described step (1), according to formula W _d=ζ * W _ecalculate the maximum wind load of reality of overhead transmission line; Wherein, W _dthe maximum wind load of reality for overhead transmission line, ζ is that the fatigue of overhead transmission line loses coefficient, W _efor the specified maximum wind load (parameter of dispatching from the factory of circuit) of overhead transmission line.

In described step (1), the method set up about the Normal probability distribution of the actual maximum wind load of overhead transmission line is: first, makes the actual maximum wind load of overhead transmission line be the average μ of Normal probability distribution _d; Then, according to formula σ _d=Z* μ _dcalculate the standard deviation sigma of Normal probability distribution _d, Z is given variation coefficient; Finally, according to average μ _dand standard deviation sigma _dsimulate the Normal probability distribution about the actual maximum wind load of overhead transmission line.

N the described time period is one group of continuous print time period and the period size of each time period is all equal; Described current time is the cut-off time of last time period in n time period.

In described step (4), according to following formulae discovery current time overhead transmission line time become stoppage in transit probability:

$P=1-{\∫}_0^{+\mathrm{\∞}}\exp \{-{\[1+{\mathrm{\ξ}}_x\left(\frac{W_x-{\mathrm{\μ}}_x}{{\mathrm{\σ}}_x}\right)\]}^{-1/{\mathrm{\ξ}}_x}\}\frac{1}{{\mathrm{\σ}}_d\sqrt{2\mathrm{\π}}}{e}^{\frac{{(W_d-{\mathrm{\μ}}_d)}^2}{2{{\mathrm{\σ}}_d}^2}}{\mathrm{dW}}_d$

Wherein: P be current time overhead transmission line time become stoppage in transit probability, W _dthe maximum wind load of reality for overhead transmission line, W _xfor the actual wind load of current time overhead transmission line, μ _x, σ _xand ξ _xbe respectively the location parameter of generalized extreme value distribution, scale parameter and form parameter, μ _dand σ _dbe respectively average and the standard deviation of Normal probability distribution.

For any instant, calculate the actual wind load of this moment overhead transmission line according to following formula:

W＝6.25×10 ^-4α _cμ _cβ _cdL(Kv) ²(sinθ) ²

Wherein: W is the actual wind load of this moment overhead transmission line, α _cfor the wind evil attacking lung of overhead transmission line, μ _cfor the Shape Coefficient of overhead transmission line, β _cfor the wind of overhead transmission line carries regulation coefficient, d is the external diameter of overhead transmission line, the horizontal span of two shaft towers that L connects for overhead transmission line, the wind speed height change factor that K is highly corresponding residing for overhead transmission line; The wind speed of v residing for this moment overhead transmission line, the wind direction of θ residing for this moment overhead transmission line and the angle between overhead transmission line axis.

Advantageous Effects of the present invention is:

(1) the present invention is according to the change of strong wind parameter, in conjunction with the wind load design level of overhead transmission line circuit, performance analysis transmission line of electricity time become stoppage in transit probability, provide important theoretical decision-making foundation for electric system disaster prevention sexual behavior.

(2) the present invention is except considering the impact of short-term strong wind disaster, also consider that overhead transmission line is exposed to the fatigue caused under each extraneous rugged surroundings and loses factor in long service, can under the reflection strong wind disaster of objective overhead transmission line time become stoppage in transit probability.

Accompanying drawing explanation

Fig. 1 is the steps flow chart schematic diagram of Probabilistic estimation of the present invention.

Fig. 2 is the tub curve schematic diagram of line failure rate.

Fig. 3 is that disaster caused by a windstorm weather surveys wind speed curve figure in lower 96 hours.

Fig. 4 is that disaster caused by a windstorm weather surveys wind direction curve map in lower 96 hours.

Fig. 5 (a) is circuit L ₁wind loads distribution probability density function schematic diagram 0 ~ 12 time.

Fig. 5 (b) is circuit L ₁wind loads distribution probability density function schematic diagram 12 ~ 24 time.

Fig. 5 (c) is circuit L ₁wind loads distribution probability density function schematic diagram 24 ~ 36 time.

Fig. 5 (d) is circuit L ₁wind loads distribution probability density function schematic diagram 36 ~ 48 time.

Fig. 5 (e) is circuit L ₁wind loads distribution probability density function schematic diagram 48 ~ 60 time.

Fig. 5 (f) is circuit L ₁wind loads distribution probability density function schematic diagram 60 ~ 72 time.

Fig. 5 (g) is circuit L ₁wind loads distribution probability density function schematic diagram 72 ~ 84 time.

Fig. 5 (h) is circuit L ₁wind loads distribution probability density function schematic diagram 84 ~ 96 time.

Fig. 6 (a) is circuit L ₂wind loads distribution probability density function schematic diagram 0 ~ 12 time.

Fig. 6 (b) is circuit L ₂wind loads distribution probability density function schematic diagram 12 ~ 24 time.

Fig. 6 (c) is circuit L ₂wind loads distribution probability density function schematic diagram 24 ~ 36 time.

Fig. 6 (d) is circuit L ₂wind loads distribution probability density function schematic diagram 36 ~ 48 time.

Fig. 6 (e) is circuit L ₂wind loads distribution probability density function schematic diagram 48 ~ 60 time.

Fig. 6 (f) is circuit L ₂wind loads distribution probability density function schematic diagram 60 ~ 72 time.

Fig. 6 (g) is circuit L ₂wind loads distribution probability density function schematic diagram 72 ~ 84 time.

Fig. 6 (h) is circuit L ₂wind loads distribution probability density function schematic diagram 84 ~ 96 time.

Fig. 7 is circuit L ₁with circuit L ₂the curve map of stoppage in transit probability under disaster caused by a windstorm weather in 96 hours.

Embodiment

In order to more specifically describe the present invention, below in conjunction with the drawings and the specific embodiments, technical scheme of the present invention and relative theory thereof are described in detail.

As shown in Figure 1, a kind of method of estimation for becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line, comprises the steps:

(1) ask for the maximum wind load of reality of circuit and set up its Normal probability distribution.

First, according to the active time of overhead transmission line to be assessed, determine that the fatigue of overhead transmission line loses coefficient ζ; The possibility that overhead transmission line breaks down can change along with the growth of active time, generally characterizes with tub curve, as shown in Figure 2; The stoppage in transit probability estimate that overhead transmission line is in trial run period does not have practical significance.

If overhead transmission line is in steady operation period, its fatigue loses coefficient ζ=1;

If overhead transmission line is in the loss phase, its fatigue is lost coefficient ζ and is tried to achieve according to following formula:

$\mathrm{\ζ}={\mathrm{\ζ}}_2{\left(\frac{t}{\mathrm{\α}}\right)}^{log\left({\mathrm{\β}}^{\frac{1}{\mathrm{\β}-1}}\right){\mathrm{\ζ}}_2}$

Wherein: α and β is respectively scale parameter and the form parameter of overhead transmission line, ζ ₂for losing coefficient with reference to fatigue, lose coefficient ζ with reference to fatigue ₂tried to achieve by following process:

First, the actual maximum wind load W of reference of overhead transmission line is gone out according to following formulae discovery _c:

W _c＝6.25×10 ^-4α _cμ _cβ _cdL(Kv _c) ²(sinθ _c) ²

Wherein: α _cfor the wind evil attacking lung of overhead transmission line, μ _cfor the Shape Coefficient of overhead transmission line, β _cfor the wind of overhead transmission line carries regulation coefficient, d is the external diameter of overhead transmission line, the horizontal span of two shaft towers that L connects for overhead transmission line, and K is the wind speed height change factor that overhead transmission line residing height h is corresponding; v _cfor overhead transmission line location is when the annual mean wind speed in the previous year, θ _cfor overhead transmission line location is when the annual wind direction in the previous year and the angle between overhead transmission line axis;

Then, according to formula ζ ₂=W _c/ W _ecalculate and lose coefficient ζ with reference to fatigue ₂; Wherein, W _efor the specified maximum wind load of overhead transmission line.

Overhead transmission line to be assessed in present embodiment has two, two overhead transmission line L ₁~ L ₂line parameter circuit value as shown in table 1, wherein, circuit L ₁active time 25 years for being in steady operation period, circuit L ₂active time 32 years is for being in the loss phase; The form parameter β of circuit can be different with the difference of the phase of military service, and other parameters are the intrinsic parameter of circuit.

Table 1

Circuit	α c	μ c	β c	d(mm)	L(m)	K
							L 1	0.85	1.1	1	18	300	0.937
L 2	0.85	1.1	1	18	300	0.937
							Circuit	W e(N)	Z	h	α	β	Active time (year)
L 1	2850	0.1	300	40	1	25
							L 2	2850	0.1	300	40	7.47	32

And then lose coefficient ζ according to fatigue and pass through formula W then, _d=ζ * W _ecalculate the maximum wind load W of reality of overhead transmission line _d, and then set up about the actual maximum wind load W of overhead transmission line _dnormal probability distribution:

First, the actual maximum wind load W of overhead transmission line is made _dfor the average μ of Normal probability distribution _d; Then, according to formula σ _d=Z* μ _dcalculate the standard deviation sigma of Normal probability distribution _d, Z is given variation coefficient; Finally, according to average μ _dand standard deviation sigma _dsimulate the Normal probability distribution about the actual maximum wind load of overhead transmission line, its expression is as follows:

$G(W_d,{\mathrm{\μ}}_d,{\mathrm{\σ}}_d)=\frac{1}{{\mathrm{\σ}}_d\sqrt{2\mathrm{\π}}}{e}^{-\frac{{(w_d-{\mathrm{\μ}}_d)}^2}{2{{\mathrm{\σ}}_d}^2}}$

(2) acquisition history wind load extreme value sample is calculated.

N time period before determining current time and the sample frequency of each time period; N time period is one group of continuous print time period and the period size of each time period is all equal; Current time is the cut-off time of last time period in n time period.In present embodiment, n is 24, and the length of each time period is half an hour, and the sample frequency of each time period is 10 minutes 1 time.

For any time period, calculate the actual wind load of each sampling instant overhead transmission line in this time period, and get the wind load extreme value of maximal value as this time period overhead transmission line of the corresponding actual wind load of each sampling instant in this time period; Travel through each time period according to this, obtain n wind load extreme value corresponding to n time period;

For any instant, calculate the actual wind load of this moment overhead transmission line according to following formula:

W＝6.25×10 ^-4α _cμ _cβ _cdL(Kv) ²(sinθ) ²

Wherein: W is the actual wind load of this moment overhead transmission line, the wind speed of v residing for this moment overhead transmission line, the wind direction of θ residing for this moment overhead transmission line and the angle between overhead transmission line axis.

(3) generalized extreme value distribution of actual wind load is set up.

Build the extreme value sample sequence be made up of n wind load extreme value, according to extreme value sample sequence by maximum likelihood estimate, simulate the generalized extreme value distribution about the actual wind load of overhead transmission line; Expression is as follows:

$F(W_x;{\mathrm{\μ}}_x,{\mathrm{\σ}}_x,{\mathrm{\ξ}}_x)=\exp \{-{\[1+{\mathrm{\ξ}}_x\left(\frac{W_x-{\mathrm{\μ}}_x}{{\mathrm{\σ}}_x}\right)\]}^{-1/{\mathrm{\ξ}}_x}\}$

Wherein: μ _x, σ _xand ξ _xbe respectively the location parameter of generalized extreme value distribution, scale parameter and form parameter, W _xfor actual wind load.

(4) by interference surface area method estimation of line time become stoppage in transit probability.

According to about the actual Normal probability distribution of maximum wind load of overhead transmission line and the generalized extreme value distribution about the actual wind load of overhead transmission line, solved by Stress strength interference area-method and obtain following formula; In present embodiment, the application of Stress strength interference area-method is using maximum for reality wind load normpdf figure and actual wind load the extreme value distribution probability density function figure as intensity pattern and stress pattern, both are intervene area by lap, are characterized the stoppage in transit probability of circuit by intervene area.

$P=1-{\∫}_0^{+\mathrm{\∞}}\exp \{-{\[1+{\mathrm{\ξ}}_x\left(\frac{W_x-{\mathrm{\μ}}_x}{{\mathrm{\σ}}_x}\right)\]}^{-1/{\mathrm{\ξ}}_x}\}\frac{1}{{\mathrm{\σ}}_d\sqrt{2\mathrm{\π}}}{e}^{-\frac{{(W_d-{\mathrm{\μ}}_d)}^2}{2{{\mathrm{\σ}}_d}^2}}{\mathrm{dW}}_d$

Wherein: P be current time overhead transmission line time become stoppage in transit probability, W _dthe maximum wind load of reality for overhead transmission line, W _xfor the actual wind load of current time overhead transmission line, μ _x, σ _xand ξ _xbe respectively the location parameter of generalized extreme value distribution, scale parameter and form parameter, μ _dand σ _dbe respectively average and the standard deviation of Normal probability distribution.The actual wind load W of current time overhead transmission line _xask for by the formula in step (2).

Present embodiment is between strong wind disaster phase, and the wind speed put each sampling time, wind direction carry out record, under calculating point of each sampling time one by one, and the actual wind load of overhead transmission line; And half an hour is chosen once maximum actual wind load at interval.The all maximum actual wind load calculated in per 12 hours half a day is formed overhead transmission line wind load extreme value sample sequence, carried out the generalized extreme value distribution parameter of matching overhead transmission line actual loading by maximal possibility estimation.Corresponding wind loads distribution probability density function, as shown in Fig. 5 (a) ~ Fig. 5 (h) and Fig. 6 (a) ~ Fig. 6 (h), respectively illustrates overhead transmission line L ₁and L ₂during 4 days large disaster caused by a windstorm evils, the development of actual maximum wind load and actual wind load; The wind speed and direction parameter of strong wind disaster actual observation in 4 days 96 hours as shown in Figure 3 and Figure 4.

Consider that fatigue loses effect, utilize Stress strength interference area-method, under calculating strong wind disaster, become stoppage in transit probability during overhead transmission line, as shown in Figure 7, concrete stoppage in transit probability is as shown in table 2:

Table 2

Time (h)	Circuit L 1Stoppage in transit probability	Circuit L 2Stoppage in transit probability
			12	6.46×10 -9	1.34×10 -5
24	7.72×10 -6	0.0021
			36	0.0127	0.1631
48	0.0679	0.6607
			60	0.5787	0.9606
72	0.7799	0.9852
			84	0.0423	0.1077
96	6.3×10 -7	0.0004

The development of strong wind disaster is that a wind-force develops into strong wind disaster from little gradually, then the dynamic process reduced gradually.Fig. 7 and table 2 shows, along with the active development of strong wind disaster, the stoppage in transit probability of overhead transmission line also produces dynamic change: in the stage of blowing, probability of malfunction is less; Along with strong wind wind-force strengthens gradually, when developing into severe disaster, overhead transmission line line outage probability level also significantly rises thereupon; After strong wind disaster is spent, when wind-force reduces gradually, the probability of malfunction of overhead transmission line also reduces gradually, and safe and reliable level raises.Result and convention are coincide.

Meanwhile, as can be seen from Figure 7, due to overhead transmission line L ₂enlistment age is longer than overhead transmission line L ₁, relative to designed wind load level, its actual wind load that can bear is lost.So under same strong wind disaster scenarios it, overhead transmission line L ₂stoppage in transit probability higher than overhead transmission line L ₁stoppage in transit probability, more easily break down; The 3rd day time, its stoppage in transit probability is almost close to 1, and this illustrates that overhead transmission line almost cannot bear so large wind-force, is in malfunction, and this point is very identical with convention.

Therefore present embodiment can quantize the dynamic change level being reflected in strong wind hazardous condition line stoppage in transit probability well, facilitates management and running personnel to obtain the fault level of circuit, thus makes Rational Decision.

Claims (7)

1., for the method for estimation becoming stoppage in transit probability under disaster caused by a windstorm weather during overhead transmission line, comprise the steps:

(1) according to the active time of overhead transmission line to be assessed, determine that the fatigue of overhead transmission line loses coefficient, and then lose coefficient calculations according to described fatigue and go out the maximum wind load of reality of overhead transmission line and the Normal probability distribution set up about the actual maximum wind load of overhead transmission line;

(2) determine current time before n time period and the sample frequency of each time period;

For any time period, calculate the actual wind load of each sampling instant overhead transmission line in this time period, and get the wind load extreme value of maximal value as this time period overhead transmission line of the corresponding actual wind load of each sampling instant in this time period;

Travel through each time period according to this, obtain n wind load extreme value corresponding to n time period;

(3) build the extreme value sample sequence be made up of n wind load extreme value, according to described extreme value sample sequence by maximum likelihood estimate, simulate the generalized extreme value distribution about the actual wind load of overhead transmission line;

(4) according to described Normal probability distribution and generalized extreme value distribution, by Stress strength interference area-method estimate current time overhead transmission line time become stoppage in transit probability;

Described Stress strength interference area-method is using maximum for reality wind load normpdf figure and actual wind load the extreme value distribution probability density function figure as intensity pattern and stress pattern, both are intervene area by lap, are characterized the stoppage in transit probability of circuit by intervene area; Namely according to following formulae discovery current time overhead transmission line time become stoppage in transit probability:

$P=1-{\∫}_0^{+\mathrm{\∞}}\exp \{-{\[1+{\mathrm{\ξ}}_x\left(\frac{W_x-{\mathrm{\μ}}_x}{{\mathrm{\σ}}_x}\right)\]}^{-1/{\mathrm{\ξ}}_x}\}\frac{1}{{\mathrm{\σ}}_d\sqrt{2\mathrm{\π}}}{e}^{-\frac{{(W_d-{\mathrm{\μ}}_d)}^2}{2{{\mathrm{\σ}}_d}^2}}{\mathrm{dW}}_d$

Wherein: P be current time overhead transmission line time become stoppage in transit probability, W _dthe maximum wind load of reality for overhead transmission line, W _xfor the actual wind load of current time overhead transmission line, μ _x, σ _xand ξ _xbe respectively the location parameter of generalized extreme value distribution, scale parameter and form parameter, μ _dand σ _dbe respectively average and the standard deviation of Normal probability distribution.

2. method of estimation according to claim 1, is characterized in that: in described step (1), and the fatigue according to following standard determination overhead transmission line loses coefficient:

If overhead transmission line is in steady operation period, its fatigue loses coefficient ζ=1;

If overhead transmission line is in the loss phase, its fatigue is lost coefficient ζ and is tried to achieve according to following formula:

$\mathrm{\ζ}={\mathrm{\ζ}}_2{\left(\frac{t}{\mathrm{\α}}\right)}^{log\left({\mathrm{\β}}^{\frac{1}{\mathrm{\β}-1}}\right){\mathrm{\ζ}}_2}$

Wherein: α and β is respectively scale parameter and the form parameter of overhead transmission line, ζ ₂for losing coefficient with reference to fatigue, t is the time.

3. method of estimation according to claim 2, is characterized in that: described reference fatigue loses coefficient ζ ₂tried to achieve by following process:

First, the actual maximum wind load W of reference of overhead transmission line is gone out according to following formulae discovery _c:

W _c＝6.25×10 ^-4α _cμ _cβ _cdL(Kv _c) ²(sinθ _c) ²

Wherein: α _cfor the wind evil attacking lung of overhead transmission line, μ _cfor the Shape Coefficient of overhead transmission line, β _cfor the wind of overhead transmission line carries regulation coefficient, d is the external diameter of overhead transmission line, the horizontal span of two shaft towers that L connects for overhead transmission line, the wind speed height change factor that K is highly corresponding residing for overhead transmission line; v _cfor overhead transmission line location is when the annual mean wind speed in the previous year, θ _cfor overhead transmission line location is when the annual wind direction in the previous year and the angle between overhead transmission line axis;

Then, according to formula ζ ₂=W _c/ W _ecalculate and lose coefficient ζ with reference to fatigue ₂; Wherein, W _efor the specified maximum wind load of overhead transmission line.

4. method of estimation according to claim 1, is characterized in that: in described step (1), according to formula W _d=ζ * W _ecalculate the maximum wind load of reality of overhead transmission line; Wherein, W _dthe maximum wind load of reality for overhead transmission line, ζ is that the fatigue of overhead transmission line loses coefficient, W _efor the specified maximum wind load of overhead transmission line.

5. method of estimation according to claim 1, it is characterized in that: in described step (1), the method set up about the Normal probability distribution of the actual maximum wind load of overhead transmission line is: first, makes the actual maximum wind load of overhead transmission line be the average μ of Normal probability distribution _d; Then, according to formula σ _d=Z* μ _dcalculate the standard deviation sigma of Normal probability distribution _d, Z is given variation coefficient; Finally, according to average μ _dand standard deviation sigma _dsimulate the Normal probability distribution about the actual maximum wind load of overhead transmission line.

6. method of estimation according to claim 1, is characterized in that: n the described time period is one group of continuous print time period and the period size of each time period is all equal; Described current time is the cut-off time of last time period in n time period.

7. method of estimation according to claim 1, is characterized in that: for any instant, calculates the actual wind load of this moment overhead transmission line according to following formula:

W＝6.25×10 ^-4α _cμ _cβ _cdL(Kv) ²(sinθ) ²

Wherein: W is the actual wind load of this moment overhead transmission line, α _cfor the wind evil attacking lung of overhead transmission line, μ _cfor the Shape Coefficient of overhead transmission line, β _cfor the wind of overhead transmission line carries regulation coefficient, d is the external diameter of overhead transmission line, the horizontal span of two shaft towers that L connects for overhead transmission line, the wind speed height change factor that K is highly corresponding residing for overhead transmission line; The wind speed of v residing for this moment overhead transmission line, the wind direction of θ residing for this moment overhead transmission line and the angle between overhead transmission line axis.