CN104166788A - Overhead transmission line optimal economic life range assessment method - Google Patents

Abstract

The invention provides an overhead transmission line optimal economic life range assessment method. The error of a failure rate prediction result of electric transmission and transformation equipment and the subjectivity of rough calculation of partial parameters of the full-life cycle cost cause an economic life result obtained by the adoption of setting calculation to have certain deviation. The overhead transmission line optimal economic life range assessment method comprises the steps that the fuzzy comprehensive evaluation method and the analytic hierarchy process are used for calculating membership degrees of all indexes and weights of all the indexes respectively; then, training output and error calculation are conducted on three failure rates of a transmission line through a least square support vector machine together with the relevant data of the service age, the external operation environment and the quality condition of the transmission line respectively, and a failure rate prediction model of the transmission line is obtained; finally, the interval analysis method is introduced into the life cycle cost theory and the optimal economic life range of the transmission line is obtained at last. According to the overhead transmission line optimal economic life range assessment method, the characteristics that the wild operation environment of the transmission line is poor and the regional span of the transmission line is wide are fully considered, and meanwhile, the problem that for different transmission lines, a uniform life ending standard is hard to provide is solved.

Description

A kind of overhead transmission line optimal economic life-span Interval evaluation method

Technical field

The invention belongs to field of power, specifically a kind of overhead transmission line optimal economic life-span Interval evaluation method.

Background technology

Therefore as the important component part of electrical network, transmission line of electricity is various in the severe field of environment and operating condition complexity for a long time, is not reaching the desired design situations such as rate is higher, part replacement is frequent that just likely broke down before the life-span.To thering is the transmission line of electricity of certain enlistment age, carry out life appraisal, can effectively avoid because of too high failure rate or maintenance and repair cause frequently a large amount of direct economic losses, and more have immeasurable effect reducing aspect have a power failure the electrical network excessive risk operation consequence that causes and indirect economic loss.In the life cycle management asset management of electrical network, transmission line of electricity life prediction can realize the life-span coupling between grid equipment, improves plant factor, reduces electric power enterprise operation cost.In addition,, along with the continuous expansion of China's electrical network scale and the complexity day by day of electric network composition, reasonably the retired time of transmission line of electricity also can be used for instructing planning, upgrading and the transformation of following electrical network.

Failure rate forecast model based on Weibull distribution or exponential distribution was only using the enlistment age as master variable in the past, do not consider the impact of other factors on failure rate, and the order of severity of failure effect is not distinguished, calculating failure cost and maintenance cost are difficult to become more meticulous.

The subjectivity of the error that power transmission and transforming equipment failure rate predicts the outcome and overall life cycle cost partial parameters rough calculation makes the economic life result that adopts definite value to calculate have certain deviation, and then power transmission and transforming equipment is retired to be impacted to instructing.

Summary of the invention

Technical matters to be solved by this invention is to overcome the defect that above-mentioned prior art exists, a kind of overhead transmission line optimal economic life-span Interval evaluation method is provided, it takes into full account the impact of uncertain information on circuit economic life assessment result, to improve confidence level and the rationality of result.

For this reason, the present invention adopts following technical scheme: a kind of overhead transmission line optimal economic life-span Interval evaluation method, it is characterized in that,

First, according to historical statistics data, arrange and the outside running environment of classification transmission line of electricity and sole mass condition evaluation index, utilize Field Using Fuzzy Comprehensive Assessment and analytical hierarchy process to calculate respectively each index degree of membership and weight;

Then, according to the failure effect order of severity by fault be divided into generic failure (line defct, unit exception, minor failure), compared with major break down (cause seven to eight grades of power grid accidents or equal catastrophic failure) and catastrophic failure (cause one to six grade of power grid accident or on an equal basis catastrophic failure) three types, by least square method supporting vector machine, in conjunction with the enlistment age of transmission line of electricity, outside running environment and sole mass situation related data, to three of transmission line of electricity kinds of failure rates, train respectively output and error to calculate, obtain the failure rate forecast model of transmission line of electricity;

Finally, Interval Analytical Method is incorporated in overall life cycle cost theory, by line failure rate to be assessed is interval, calculate failure cost and maintenance cost and by each indicator of costs intervalization, the retired time range of transmission line of electricity that the average annual cost minimization of take is object solving optimum, eliminate the deviation of single definite value, the optimal economic life-span that finally obtains transmission line of electricity is interval.

The circuit optimal economic life-span of utilizing the present invention to judge is interval, can formulate the retired standard of circuit.If circuit surpasses optimal economic life-span interval working time, circuit is retired; If it is interval not surpass the optimal economic life-span, circuit continues operation.

The present invention has taken into full account the features such as transmission line of electricity field running environment is severe, region span is large, has solved the problem that dissimilar transmission line of electricity is difficult to provide unified end-of-life standard simultaneously.

The present invention adopts following concrete steps:

Step 1), the foundation of the outside running environment of transmission line of electricity and sole mass condition evaluation set of factors, index set and comment collection,

Set of factors Ji Ge lower floor index is divided into 4 comment grades, and comment integrates as V={v ₁, v ₂, v ₃, v ₄}={ is good, fair, general, bad };

Step 2), the calculating of the outside running environment of transmission line of electricity and sole mass condition evaluation index degree of membership and weight,

Being calculated as follows of index degree of membership: by making evaluation table to every expert, calculate the degree of membership of each index according to expert's evaluation situation, index degree of membership r _ijcomputing formula as follows:

$r_{\mathrm{ij}}=\frac{P_{\mathrm{ij}}}{P_{\mathrm{total}}}$

In formula, P _ijrepresent to think in set of factors that i index belongs to comment v _jexpert's number, P _totalrepresent to participate in expert's total number of persons of evaluation, i=1,2 ..., u, u is the index number in set of factors, j=1-4, after trying to achieve the degree of membership of index set, can obtain set of factors fuzzy membership matrix R;

" 9 indexing " in definite employing analytical hierarchy process (AHP) of index weights, sorts after calculating through expert, can obtain each index weights vector of set of factors W;

Step 3), comprehensive assessment and the scoring of outside running environment and sole mass situation, the computing formula of its Fuzzy comprehensive evaluation vector B is as follows:

B＝WoR

In formula, R is set of factors fuzzy membership matrix, and W is each index weights vector of set of factors, and " o " is operational symbol, represents compose operation, and employing M (,+) and operator,

$b_j=\underset{i=1}{\overset{u}{\mathrm{\Σ}}}{w}_i{r}_{\mathrm{ij}}$

In formula, b _jfor set of factors is to comment v _jdegree of membership, w _ifor the weight of i index in set of factors, r _ijfor index degree of membership;

Calculate after the Fuzzy comprehensive evaluation vector of set of factors, according to maximum membership grade principle, the comprehensive assessment result of set of factors is the corresponding comment v of maximum membership degree _j; Suppose that the scoring collection that comment set pair is answered is be the corresponding corresponding scoring of corresponding comment grade, comprehensive assessment result is comment v _jset of factors scoring be

Step 4), the training of sample circuit historical data and error analysis:

Ginseng is by enlistment age in stage T, running environment scoring mark with quality condition identical transmission line of electricity is defined as similar circuit, and analyze the historical data of similar circuit during enlistment age in stage T, count respectively three class failure rates as a sample (because circuit Various Seasonal in a year has different fault types and different year because certain disaster causes floating of failure rate, therefore the statistics duration of similar line fault number of times is correspondingly made as to 5 years comparatively science)

The year failure rate λ computing formula of similar enlistment age in circuit stage is as follows, and unit is times/year hundred kilometers, $\mathrm{\λ}=\frac{{\mathrm{\Σ}}_{5\mathrm{years}}{Q}^{(T,S_{E_1},S_{E_2},S_{H_1},S_{H_2})}}{5\×\mathrm{\Σ}{l}^{(T,S_{E_1},S_{E_2},S_{H_1},S_{H_2})}},$

In formula, be the total failare number of times of similar line fault in 5 years, generic failure, compared with major break down, catastrophic failure, add up respectively, be 5 the year end similar line length and;

In transmission line malfunction rate forecast model, sample line circuit-switched data is circuit essential information vector x _m=(x _m1, x _m2, x _m3, x _m4, x _m5) and circuit physical fault rate vector λ _m=(λ _m1, λ _m2, λ _m3), wherein, m=1,2 ..., M+N, M+N is sample size; x _m1, x _m2, x _m3, x _m4, x _m5represent respectively enlistment age in stage T and the set of factors scoring of sample circuit λ _m1, λ _m2, λ _m3be respectively the generic failure of sample circuit, compared with the failure rate of major break down and catastrophic failure; Adopt the training of M group sample, N group sample makes a checking calculation, and the computing formula of error is as follows:

$\mathrm{\ϵ}=\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\frac{|{\mathrm{\λ}}_n^{\mathrm{re}}-{\mathrm{\λ}}_n^{\mathrm{pre}}|}{{\mathrm{\λ}}_n^{\mathrm{re}}}$

In formula, for the sample line failure rate actual count value as checking computations, for the sample line failure rate predicted value as checking computations, N is the sample size as checking computations, and ε is AME;

Step 5), the failure rate interval prediction of circuit to be assessed:

When circuit to be assessed is carried out to failure rate prediction, the running environment set of factors scoring of this circuit with by circuit corridor environmental aspect over the years after putting into operation, judge the scoring of quality condition set of factors with according to circuit operating maintenance record over the years and state estimation result, evaluate;

Step 6), circuit analysis of Life Cycle Cost:

When transmission line of electricity moves to L when retired, its annual cost is as follows:

${\mathrm{NF}}_L=\frac{1}{L}[\mathrm{IC}+\underset{t=1}{\overset{L}{\mathrm{\Σ}}}({\mathrm{OC}}_t+{\mathrm{MC}}_t+{\mathrm{FC}}_t){\left(\frac{1+R}{1+r}\right)}^t-\mathrm{DC}{\left(\frac{1+R}{1+r}\right)}^L],t=\mathrm{1,2},\·\·\·,L$

In formula, the operation year number that L is transmission line of electricity, NF _lfor the annual cost of transmission line of electricity operation L, IC represents initial input cost, and r is social discount rate, and obsolescence cost DC is income type cost, and R is artificial Master Cost rate of growth, OC _t, MC _t, FC _tbe respectively operating cost, maintenance cost and the failure cost of transmission line of electricity t;

Step 7), line cost intervalization is calculated:

After circuit builds up and puts into operation, disposable input cost IC fixes, and operating cost OC is in the situation that operational plan is definite, and annual expenditure is floated in an interval; After circuit is retired, obsolescence cost computing formula is as follows:

DC＝p×IC

In formula, p is that obsolescence cost number percent is interval;

After trying to achieve all kinds of costs interval, by finding Average Annual Cost NF _lthe scope of counting in operation year hour, the optimal economic life-span that can obtain transmission line of electricity is interval.

Further, step 5), in, suppose that transmission line of electricity is the longest can move to enlistment age in stage T _max, the enlistment age in stage of circuit to be assessed is arrived to " T by " 1 " _max" substitution successively, obtain each enlistment age in stage of this circuit three class year failure rate; Then, carry out year enlistment age in stage failure rate to the conversion of actual year enlistment age failure rate, conversion process is as follows: each of transmission line of electricity in bound year enlistment age in stage number average, by year enlistment age in stage failure rate be decided to be respectively circuit 3 years ' operation (1～5 year), 8 years (6～10 years) ..., 5T _max-2 years (5T _max-4～5T _maxyear) year failure rate time, adopts cubic spline interpolation, calculates transmission line of electricity operation 1-5T _maxthe year failure rate in year; Finally, according to error ε, by failure rate intervalization, calculate the failure rate scope of three class faults, failure rate intervalization formula is as follows:

$[{\mathrm{\λ}}_t^{\min },{\mathrm{\λ}}_t^{\max }]=[(1-\mathrm{\ϵ}){\mathrm{\λ}}_t,(1+\mathrm{\ϵ}){\mathrm{\λ}}_t]$

be respectively lower limit and the upper limit of t line failure rate, λ _tfor t line failure rate predicted value after interpolation arithmetic.

Further, step 6) in, the maintenance cost MC that transmission line of electricity t is required _twith failure cost FC _trelevant with failure rate, computing formula is as follows:

${\mathrm{MC}}_t=\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{M}_k{\mathrm{\λ}}_k\left(t\right)l$

${\mathrm{FC}}_t=\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{F}_k{\mathrm{\λ}}_k\left(t\right)l$

Subscript k=1,2,3 represents respectively generic failure, compared with major break down, catastrophic failure, λ _k(t) be line failure rate, l is transmission line length, M _kfor averaging section renewal cost and the artificial maintenance cost of the each fault of transmission line of electricity, F _kthe average comprehensive loss causing for transmission line malfunction.

Further, step 6) in, social discount rate r, maintenance cost M _k, failure cost F _k, artificial material cost increases rate R all adopts interval number to represent.

Further, step 4) in, when transmission line malfunction rate is trained to calculating, adopt the transmission line of electricity data (transmission line of electricity electric pressure is different, and failure rate difference is very large) of identical electric pressure.

Further, step 4) in, the circuit of take initially drops into days and carries out enlistment age statistics as benchmark, during statistics, with 5 Nian Wei unit's calculation stages enlistment age T, supposes certain circuit Z that put into operation, and its enlistment age in stage is wherein for on round symbol.For example the enlistment age is that its enlistment age in stage of circuit of " 6-10 " is " 2 ".

The present invention combines complex characteristics and the failure rate error analysis of the aging and fault of transmission line of electricity " multifactor impact; many consequences form ", compare with the power transmission and transforming equipment bathtub curve matching forecast model of single enlistment age variable in the past, transmission line malfunction rate is predicted the outcome more reasonable.Transmission line of electricity is carried out to analysis of Life Cycle Cost and intervalization, and it is interval to using the circuit optimal economic life-span that average annual cost minimization tries to achieve combined reliability and economic index as criterion, take into full account the impact of uncertain information on circuit economic life assessment result, improved confidence level and the rationality of result.The present invention has taken into full account the features such as transmission line of electricity field running environment is severe, region span is large, has solved the problem that dissimilar transmission line of electricity is difficult to provide unified end-of-life standard simultaneously.

Accompanying drawing explanation

Fig. 1 is line failure rate forecast model process flow diagram of the present invention.

Fig. 2 a～c is example circuit in application examples (circuit 1 and circuit 2) generic failure, compared with the bathtub curve of major break down, catastrophic failure, (curve above in figure is circuit 1, a curve is below circuit 2), wherein Fig. 2 a is the bathtub curve of circuit 1 and circuit 2 generic failures, Fig. 2 b be circuit 1 and circuit 2 compared with the bathtub curve of major break down, Fig. 2 c is the bathtub curve of circuit 1 and circuit 2 catastrophic failures.

Fig. 3 a～b is circuit 1 and the average annual overall life cycle cost curve of circuit 2 in application examples.Fig. 3 a is the average annual overall life cycle cost bound curve of circuit 1, and Fig. 3 b is the average annual overall life cycle cost bound curve of circuit 2.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described, the present invention includes following steps:

Step (1), the foundation of circuit running environment and quality condition appraisal parameters, index set and comment collection.Specifically:

Transmission line of electricity running environment and quality condition appraisal parameters and index set are as shown in table 1.

Table 1 transmission line of electricity running environment and quality condition appraisal parameters and index set

Set of factors Ji Ge lower floor index is divided into 4 comment grades, and comment collection is: V={v ₁, v ₂, v ₃, v ₄}={ is good, fair, general, bad }.

Step (2), the calculating of circuit running environment and quality condition evaluation index degree of membership and weight.Specifically:

The calculating of index degree of membership adopts Field Using Fuzzy Comprehensive Assessment.By making evaluation table to every expert, according to expert's evaluation situation, calculate the degree of membership of each index, index degree of membership r _ijcomputing formula as follows:

$r_{\mathrm{ij}}=\frac{P_{\mathrm{ij}}}{P_{\mathrm{total}}}$

In formula, P _ijrepresent to think in set of factors that i index belongs to comment v _jexpert's number, P _totalrepresent to participate in expert's total number of persons of evaluation, i=1,2 ..., u, u is the index number in set of factors, j=1-4.After trying to achieve the degree of membership of index set, can obtain set of factors fuzzy membership matrix R.

" 9 indexing " in definite employing analytical hierarchy process (AHP) of index weights, sorts after calculating through expert, can obtain each index weights vector of set of factors W.

Set of factors fuzzy membership matrix and index weights vector example are as follows:

Step (3), the comprehensive assessment of running environment and quality condition and scoring.Specifically:

B is Fuzzy comprehensive evaluation vector, and its computing formula is as follows:

B＝WoR

In formula, " o " is operational symbol, represents compose operation, and the present invention adopts M (,+) operator,

$b_j=\underset{i=1}{\overset{u}{\mathrm{\Σ}}}{w}_i{r}_{\mathrm{ij}}$

In formula, b _jfor set of factors is to comment v _jdegree of membership, w _iweight for i index in set of factors.

Calculate after the Fuzzy comprehensive evaluation vector of set of factors, according to maximum membership grade principle, the comprehensive assessment result of set of factors is the corresponding comment v of maximum membership degree _j.The present invention supposes that the scoring collection that comment set pair is answered is be the corresponding corresponding scoring of corresponding comment grade, comprehensive assessment result is comment v _jset of factors scoring be

Step (4), the training of sample circuit historical data and error analysis.Specifically:

The input message of training sample circuit is had to following explanation.

1) transmission line of electricity electric pressure is different, and failure rate difference is larger, while therefore transmission line malfunction rate being trained to calculating, adopts the transmission line of electricity data of identical electric pressure.

2) standard about transmission line malfunction consequence of promulgating with reference to national grid, according to the order of severity by fault be divided into generic failure (line defct, unit exception, minor failure), compared with major break down (cause seven to eight grades of power grid accidents or equal catastrophic failure), catastrophic failure (causing one to six grade of power grid accident or equal catastrophic failure) three types, add up respectively circuit three class failure rates.

3) take circuit and initially drop into days and carry out enlistment age statistics as benchmark, during statistics, with 5 Nian Wei unit's calculation stages enlistment age T, suppose certain circuit Z that put into operation, its enlistment age in stage is wherein for on round symbol.For example the enlistment age is that its enlistment age in stage of circuit of " 6～10 years " is " 2 ".

4) by enlistment age in stage T, running environment scoring mark with quality condition identical transmission line of electricity is defined as similar circuit, and analyzes the historical data of similar circuit during enlistment age in stage T, counts respectively three class failure rates as a sample.Because circuit Various Seasonal in a year has different fault types and different year because certain disaster causes floating of failure rate, therefore the statistics duration of similar line fault number of times is correspondingly made as to 5 years comparatively science.

The year failure rate λ computing formula of similar enlistment age in circuit stage is as follows, and unit is times/year hundred kilometers.

$\mathrm{\λ}=\frac{{\mathrm{\Σ}}_{5\mathrm{years}}{Q}^{(T,S_{E_1},S_{E_2},S_{H_1},S_{H_2})}}{5\×\mathrm{\Σ}{l}^{(T,S_{E_1},S_{E_2},S_{H_1},S_{H_2})}}$

In formula, be the total failare number of times (generic failure, add up respectively compared with major break down, catastrophic failure) of similar line fault in 5 years, be 5 the year end similar line length and.

In transmission line malfunction rate forecast model, sample line circuit-switched data is circuit essential information vector x _m=(x _m1, x _m2, x _m3, x _m4, x _m5) and circuit physical fault rate vector λ _m=(λ _m1, λ _m2, λ _m3), wherein, m=1,2 ..., M+N (M+N is sample size).X _m1, x _m2, x _m3, x _m4, x _m5represent respectively enlistment age in stage T and the set of factors scoring of sample circuit λ _m1, λ _m2, λ _m3be respectively the generic failure of sample circuit, compared with the failure rate of major break down and catastrophic failure.The present invention adopts the training of M group sample, and N group sample makes a checking calculation, and the computing formula of error is as follows:

$\mathrm{\ϵ}=\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\frac{|{\mathrm{\λ}}_n^{\mathrm{re}}-{\mathrm{\λ}}_n^{\mathrm{pre}}|}{{\mathrm{\λ}}_n^{\mathrm{re}}}$

In formula, for the sample line failure rate actual count value as checking computations, for the sample line failure rate predicted value as checking computations, N is the sample size as checking computations, and ε is AME.

Step (5), the failure rate interval prediction of circuit to be assessed.Specifically:

When circuit to be assessed is carried out to failure rate prediction, the running environment set of factors scoring of this circuit with by circuit corridor environmental aspect over the years after putting into operation, judge the scoring of quality condition set of factors with according to circuit operating maintenance record over the years and state estimation result, evaluate.

Supposing that transmission line of electricity is the longest can move to enlistment age in stage T _max, the enlistment age in stage of circuit to be assessed is arrived to " T by " 1 " _max" substitution successively, obtain each enlistment age in stage of this circuit three class year failure rate.Then, carry out year enlistment age in stage failure rate to the conversion of actual year enlistment age failure rate, conversion process is as follows: each of transmission line of electricity in bound year enlistment age in stage number average, by year enlistment age in stage failure rate be decided to be respectively circuit 3 years ' operation (1～5 year), 8 years (6～10 years) ... 5T _max-2 years (5T _max-4～5T _maxyear) year failure rate time, adopts cubic spline interpolation, calculates transmission line of electricity operation 1～5T _maxthe year failure rate in year.Finally, according to error ε, by failure rate intervalization, calculate the failure rate scope of three class faults.Failure rate intervalization formula is as follows:

$[{\mathrm{\λ}}_t^{\min },{\mathrm{\λ}}_t^{\max }]=[(1-\mathrm{\ϵ}){\mathrm{\λ}}_t,(1+\mathrm{\ϵ}){\mathrm{\λ}}_t]$

be respectively lower limit and the upper limit of t line failure rate, λ _tfor t line failure rate predicted value after interpolation arithmetic.

The process flow diagram of the failure rate forecast model of assessment circuit is shown in Fig. 1.

Step (6), circuit analysis of Life Cycle Cost.Specifically:

When transmission line of electricity moves to L when retired, its annual cost is as follows:

${\mathrm{NF}}_L=\frac{1}{L}[\mathrm{IC}+\underset{t=1}{\overset{L}{\mathrm{\Σ}}}({\mathrm{OC}}_t+{\mathrm{MC}}_t+{\mathrm{FC}}_t){\left(\frac{1+R}{1+r}\right)}^t-\mathrm{DC}{\left(\frac{1+R}{1+r}\right)}^L],t=\mathrm{1,2},\·\·\·,L$

In formula, the operation year number that L is transmission line of electricity, NF _lfor the annual cost of transmission line of electricity operation L, IC represents initial input cost, and r is social discount rate, and obsolescence cost DC is income type cost, and R is artificial Master Cost rate of growth.OC _t, MC _t, FC _tbe respectively operating cost, maintenance cost and the failure cost of transmission line of electricity t.

The maintenance cost MC that transmission line of electricity t is required _twith failure cost FC _trelevant with failure rate, computing formula is as follows:

${\mathrm{MC}}_t=\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{M}_k{\mathrm{\λ}}_k\left(t\right)l$

${\mathrm{FC}}_t=\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{F}_k{\mathrm{\λ}}_k\left(t\right)l$

Subscript k=1,2,3 represents respectively generic failure, compared with major break down, catastrophic failure, λ _k(t) be line failure rate, l is transmission line length, M _kfor averaging section renewal cost and the artificial maintenance cost of the each fault of transmission line of electricity, F _kthe average comprehensive loss causing for transmission line malfunction.

Step (7), line cost intervalization is calculated.Specifically:

After circuit builds up and puts into operation, disposable input cost IC fixes.Operating cost OC is in the situation that operational plan is definite, and annual expenditure is in an interval unsteady (the present invention disregards line loss) substantially.After circuit is retired, obsolescence cost computing formula is as follows:

DC＝p×IC

In formula, p is that obsolescence cost number percent is interval.In addition social discount rate r, maintenance cost M, _k, failure cost F _k, artificial material cost increases rate R all adopts interval number to represent.

After trying to achieve all kinds of costs interval, by finding Average Annual Cost NF _lthe scope of counting in operation year hour, the optimal economic life-span that can obtain transmission line of electricity is interval.

Application examples

For verifying the feasibility of above-mentioned overhead transmission line optimal economic life-span Interval evaluation method.Choose two, somewhere 220kV overhead transmission line and carry out optimal economic life-span Interval evaluation.Circuit 1 total length 42.9km, put into operation in July, 2005, and while building up, total price is 2143.3 ten thousand yuan; Circuit 2 total length 37.8km, put into operation in November, 2004, and while building up, total price is 1873.5 ten thousand yuan.

By multidigit expert's evaluation, the Result of Fuzzy Comprehensive Evaluation of circuit 1 and circuit 2 each set of factors is as follows:

$\begin{array}{cc}{B}_{E_1}^{\mathrm{line}1}=\left[\begin{array}{cccc}0.0948& 0.2080& 0.5907& 0.1065\end{array}\right]& B_{E_1}^{\mathrm{line}2}=\left[\begin{array}{cccc}0.1436& 0.4925& 0.2211& 0.1428\end{array}\right]\\ B_{E_2}^{\mathrm{line}1}=\left[\begin{array}{cccc}0.2260& 0.5314& 0.2122& 0.0304\end{array}\right]& B_{E_2}^{\mathrm{line}2}=\left[\begin{array}{cccc}0.4640& 0.2682& 0.2009& 0.0669\end{array}\right]\\ B_{H_1}^{\mathrm{line}1}=\left[\begin{array}{cccc}0.1333& 0.4662& 0.2471& 0.1534\end{array}\right]& B_{H_1}^{\mathrm{line}2}=\left[\begin{array}{cccc}0.5035& 0.2664& 0.1524& 0.0777\end{array}\right]\\ B_{H_2}^{\mathrm{line}1}=\left[\begin{array}{cccc}0.1508& 0.2358& 0.5142& 0.0992\end{array}\right]& B_{H_2}^{\mathrm{line}2}=\left[\begin{array}{cccc}0.1662& 0.5098& 0.2248& 0.0992\end{array}\right]\end{array}$

Can obtain the E of circuit 1 and circuit 2 ₁, E ₂, H ₁, H ₂assessment result is general, fair, fair, general, i.e. S _line1={ 3,2,2,3} and fair, good, good, fair, i.e. S _line2={ 2,1,1,2}.

Training output and interpolation arithmetic through failure rate forecast model, obtain the bathtub curve of circuit 1 and circuit 2 three class faults as shown in Fig. 2 a～c.According to checking computation results error, calculate, the error ε that gets failure rate is 7.5%.

With reference to the relevant historical data of local electric power enterprise, between each cost of transmission line of electricity and related economic parameter region as table 2.

Between each cost of table 2 transmission line of electricity and related economic parameter region

Cost and related economic parameter	Interval range
		Operating cost OC(ten thousand yuan/year hundred kilometers)	[13,16]
Generic failure is maintenance and failure cost and (ten thousand yuan/time) on average	[10,12]
		Compared with major break down on average maintenance and failure cost and (ten thousand yuan/time)	[121,128]
Catastrophic failure is maintenance and failure cost and (ten thousand yuan/time) on average	[406,419]
		Social discount rate r	[0.055,0.06]
Artificial material cost increases rate R	[0.053,0.058]
		Obsolescence cost number percent p	[0.35,0.4]

Annual cost upper lower limit value while calculating circuit 1 with circuit 2 difference operation year number by the data in table 2 is also depicted as curve, as shown in Fig. 3 a～b.

In Fig. 3 a～b, circuit 1 and circuit 2 economic life under high failure rate and high O&M failure cost is 27 years and 30 years, economic life under less trouble and low O&M failure cost is 29 years and 32 years, and the optimal economic life-span interval of circuit 1 and circuit 2 is respectively 27～29 years and 30～32 years.Show thus, different transmission lines of electricity running environment of living in is different with quality condition, and its optimal economic life-span interval will change.

Claims (7)

1. an overhead transmission line optimal economic life-span Interval evaluation method, is characterized in that,

First, according to historical statistics data, arrange and the outside running environment of classification transmission line of electricity and sole mass condition evaluation index, utilize Field Using Fuzzy Comprehensive Assessment and analytical hierarchy process to calculate respectively each index degree of membership and weight;

Then, according to the failure effect order of severity by fault be divided into generic failure, compared with major break down and catastrophic failure three types, by least square method supporting vector machine, in conjunction with the enlistment age of transmission line of electricity, outside running environment and sole mass situation related data, to three of transmission line of electricity kinds of failure rates, train respectively output and error to calculate, obtain the failure rate forecast model of transmission line of electricity;

Finally, Interval Analytical Method is incorporated in overall life cycle cost theory, by line failure rate to be assessed is interval, calculate failure cost and maintenance cost and by each indicator of costs intervalization, the retired time range of transmission line of electricity that the average annual cost minimization of take is object solving optimum, eliminate the deviation of single definite value, the optimal economic life-span that finally obtains transmission line of electricity is interval.

2. overhead transmission line optimal economic life-span Interval evaluation method according to claim 1, is characterized in that, it adopts following concrete steps:

Step 1), the foundation of the outside running environment of transmission line of electricity and sole mass condition evaluation set of factors, index set and comment collection,

Set of factors Ji Ge lower floor index is divided into 4 comment grades, and comment integrates as V={v ₁, v ₂, v ₃, v ₄}={ is good, fair, general, bad };

Step 2), the calculating of the outside running environment of transmission line of electricity and sole mass condition evaluation index degree of membership and weight,

Being calculated as follows of index degree of membership: by making evaluation table to every expert, calculate the degree of membership of each index according to expert's evaluation situation, index degree of membership r _ijcomputing formula as follows:

$r_{\mathrm{ij}}=\frac{P_{\mathrm{ij}}}{P_{\mathrm{total}}},$

In formula, P _ijrepresent to think in set of factors that i index belongs to comment v _jexpert's number, P _totalrepresent to participate in expert's total number of persons of evaluation, i=1,2 ..., u, u is the index number in set of factors, j=1-4, after trying to achieve the degree of membership of index set, can obtain set of factors fuzzy membership matrix R;

" 9 indexing " in definite employing analytical hierarchy process of index weights, sorts after calculating through expert, can obtain each index weights vector of set of factors W;

Step 3), comprehensive assessment and the scoring of outside running environment and sole mass situation, the computing formula of its Fuzzy comprehensive evaluation vector B is as follows:

B＝WoR

In formula, R is set of factors fuzzy membership matrix, and W is each index weights vector of set of factors, and " o " is operational symbol, represents compose operation, and employing M (,+) and operator,

$b_j=\underset{i=1}{\overset{u}{\mathrm{\Σ}}}{w}_i{r}_{\mathrm{ij}}$

In formula, b _jfor set of factors is to comment v _jdegree of membership, w _ifor the weight of i index in set of factors, r _ijfor index degree of membership;

Calculate after the Fuzzy comprehensive evaluation vector of set of factors, according to maximum membership grade principle, the comprehensive assessment result of set of factors is the corresponding comment v of maximum membership degree _j; Suppose that the scoring collection that comment set pair is answered is be the corresponding corresponding scoring of corresponding comment grade, comprehensive assessment result is comment v _jset of factors scoring be

Step 4), the training of sample circuit historical data and error analysis:

By enlistment age in stage T, running environment scoring mark with quality condition identical transmission line of electricity is defined as similar circuit, and analyzes the historical data of similar circuit during enlistment age in stage T, counts respectively three class failure rates as a sample,

The year failure rate λ computing formula of similar enlistment age in circuit stage is as follows, and unit is times/year hundred kilometers, $\mathrm{\λ}=\frac{{\mathrm{\Σ}}_{5\mathrm{years}}{Q}^{(T,S_{E_1},S_{E_2},S_{H_1},S_{H_2})}}{5\×\mathrm{\Σ}{l}^{(T,S_{E_1},S_{E_2},S_{H_1},S_{H_2})}},$

In formula, be the total failare number of times of similar line fault in 5 years, generic failure, compared with major break down, catastrophic failure, add up respectively, be 5 the year end similar line length and;

In transmission line malfunction rate forecast model, sample line circuit-switched data is circuit essential information vector x _m=(x _m1, x _m2, x _m3, x _m4, x _m5) and circuit physical fault rate vector λ _m=(λ _m1, λ _m2, λ _m3), wherein, m=1,2 ..., M+N, M+N is sample size; x _m1, x _m2, x _m3, x _m4, x _m5represent respectively enlistment age in stage T and the set of factors scoring of sample circuit λ _m1, λ _m2, λ _m3be respectively the generic failure of sample circuit, compared with the failure rate of major break down and catastrophic failure; Adopt the training of M group sample, N group sample makes a checking calculation, and the computing formula of error is as follows:

$\mathrm{\ϵ}=\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\frac{|{\mathrm{\λ}}_n^{\mathrm{re}}-{\mathrm{\λ}}_n^{\mathrm{pre}}|}{{\mathrm{\λ}}_n^{\mathrm{re}}}$

In formula, for the sample line failure rate actual count value as checking computations, for the sample line failure rate predicted value as checking computations, N is the sample size as checking computations, and ε is AME;

Step 5), the failure rate interval prediction of circuit to be assessed:

When circuit to be assessed is carried out to failure rate prediction, the running environment set of factors scoring of this circuit with by circuit corridor environmental aspect over the years after putting into operation, judge the scoring of quality condition set of factors with according to circuit operating maintenance record over the years and state estimation result, evaluate;

Step 6), circuit analysis of Life Cycle Cost:

When transmission line of electricity moves to L when retired, its annual cost is as follows:

${\mathrm{NF}}_L=\frac{1}{L}[\mathrm{IC}+\underset{t=1}{\overset{L}{\mathrm{\Σ}}}({\mathrm{OC}}_t+{\mathrm{MC}}_t+{\mathrm{FC}}_t){\left(\frac{1+R}{1+r}\right)}^t-\mathrm{DC}{\left(\frac{1+R}{1+r}\right)}^L],t=\mathrm{1,2},\·\·\·,L$

In formula, the operation year number that L is transmission line of electricity, NF _lfor the annual cost of transmission line of electricity operation L, IC represents initial input cost, and r is social discount rate, and obsolescence cost DC is income type cost, and R is artificial Master Cost rate of growth, OC _t, MC _t, FC _tbe respectively operating cost, maintenance cost and the failure cost of transmission line of electricity t;

Step 7), line cost intervalization is calculated:

After circuit builds up and puts into operation, disposable input cost IC fixes, and operating cost OC is in the situation that operational plan is definite, and annual expenditure is floated in an interval; After circuit is retired, obsolescence cost computing formula is as follows:

DC＝p×IC

In formula, p is that obsolescence cost number percent is interval;

After trying to achieve all kinds of costs interval, by finding Average Annual Cost NF _lthe scope of counting in operation year hour, the optimal economic life-span that can obtain transmission line of electricity is interval.

3. overhead transmission line optimal economic life-span Interval evaluation method according to claim 2, is characterized in that step 5) in, suppose that transmission line of electricity is the longest can move to enlistment age in stage T _max, the enlistment age in stage of circuit to be assessed is arrived to " T by " 1 " _max" substitution successively, obtain each enlistment age in stage of this circuit three class year failure rate; Then, carry out year enlistment age in stage failure rate to the conversion of actual year enlistment age failure rate, conversion process is as follows: each of transmission line of electricity in bound year enlistment age in stage number average, by year enlistment age in stage failure rate be decided to be respectively circuit 3 years ' operation, 8 years ..., 5T _maxyear failure rate in the time of-2 years, adopts cubic spline interpolation, calculates transmission line of electricity operation 1-5T _maxthe year failure rate in year; Finally, according to error ε, by failure rate intervalization, calculate the failure rate scope of three class faults, failure rate intervalization formula is as follows:

$[{\mathrm{\λ}}_t^{\min },{\mathrm{\λ}}_t^{\max }]=[(1-\mathrm{\ϵ}){\mathrm{\λ}}_t,(1+\mathrm{\ϵ}){\mathrm{\λ}}_t]$

be respectively lower limit and the upper limit of t line failure rate, λ _tfor t line failure rate predicted value after interpolation arithmetic.

4. overhead transmission line optimal economic life-span Interval evaluation method according to claim 3, is characterized in that step 6) in, the maintenance cost MC that transmission line of electricity t is required _twith failure cost FC _trelevant with failure rate, computing formula is as follows:

${\mathrm{MC}}_t=\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{M}_k{\mathrm{\λ}}_k\left(t\right)l$

${\mathrm{FC}}_t=\underset{k=1}{\overset{3}{\mathrm{\Σ}}}{F}_k{\mathrm{\λ}}_k\left(t\right)l$

Subscript k=1,2,3 represents respectively generic failure, compared with major break down, catastrophic failure, λ _k(t) be line failure rate, l is transmission line length, M _kfor averaging section renewal cost and the artificial maintenance cost of the each fault of transmission line of electricity, F _kthe average comprehensive loss causing for transmission line malfunction.

5. overhead transmission line optimal economic life-span Interval evaluation method according to claim 4, is characterized in that step 6) in, social discount rate r, maintenance cost M _k, failure cost F _k, artificial material cost increases rate R all adopts interval number to represent.

6. overhead transmission line optimal economic life-span Interval evaluation method according to claim 1, is characterized in that step 4) in, when transmission line malfunction rate is trained to calculating, adopt the transmission line of electricity data of identical electric pressure.

7. overhead transmission line optimal economic life-span Interval evaluation method according to claim 1, it is characterized in that, step 4) in, the circuit of take initially drops into days and carries out enlistment age statistics as benchmark, during statistics with 5 Nian Wei unit's calculation stages enlistment age T, suppose certain circuit Z that put into operation, its enlistment age in stage is wherein for on round symbol.