CN105243520A - Full life-cycle cost evaluation method based on power cable heat transfer model - Google Patents

Abstract

The invention relates to a full life-cycle cost evaluation method based on a power cable heat transfer model. The full life-cycle cost evaluation method comprises the steps of: 1) acquiring cable conductor temperature according to the power cable heat transfer model; 2) calculating cable thermal life according to the cable conductor temperature; 3) establishing a full life-cycle cost model of a high-voltage cable according to the cable thermal life and an annual interest rate, and calculating to obtain an equivalent annuity of the high-voltage cable, namely, an LCC annual value of the high-voltage cable; 4) and acquiring different LCC annual values of high-voltage cables of different types from different manufacturers, and selecting the cable with the minimal LCC annual value as an optimal cable. Compared with the prior art, the full life-cycle cost evaluation method has advantages of comprehensive and scientific consideration, accurate calculation and the like.

Description

A kind of overall life cycle cost evaluation method based on power cable heat transfer model

Technical field

The present invention relates to a kind of cable cost evaluation method, especially relate to a kind of overall life cycle cost evaluation method based on power cable heat transfer model.

Background technology

LCC concept originates from the railway system of Sweden, and nineteen sixty-five, U.S. Department of Defense implemented in the entire PLA.1996 International Electrotechnical Commission (IEC) issued international standard IEC60300-3-3, and issued again revised edition in July, 2004.In June, 1999, US President Clinton endorsed governmental mandates, the equipment needed for each state government and engineering project, and requirement must have LCC to report, did not have LCC to estimate, evaluated, inaccurate signing without exception.In addition, international conference on large HV electric systems (CIGRE) also carries out equipment control at proposition overall life cycle cost in 2004, encourages manufacturer to provide the LCC of product to report.Each important power equipment manufacturer in the world, as ABB, Siemens etc., is carrying out the LCC correlative study of its product.External Utilities Electric Co. also pays much attention to LCC management, by the whole-life cycle fee strategy of asset management plan assets, as NG company of Britain, Ashburton Utilities Electric Co. of New Zealand etc.

At present, Shanghai Electric Power Co in the technology reforming scheme evaluation of calm and peaceful station, Expo becomes main equipment bid, oil becomes in the bid that case becomes and introduces the assay of LCC, achieves desirable effect.Cable line is as the important component part of cable system assets, because of the underground running environment that it is special, all comparatively complicated in operational management, state-detection, Maintenance and Repair etc., need to carry out LCC management review to cable, and check in Bids For Purchasing Equipments link, and then effectively reduce after-cost.

The on-line monitoring of current employing and detection technique include the methods such as partial discharge monitoring, on-line temperature monitoring, ground current on-line monitoring, dielectric loss angle tangent tan δ, terminal corona discharge on-line checkingi.

Namely occur aging after cable puts into operation, As time goes on, how the cable of earlier operation, close to useful life period, is changed before cable life is close to term of life, runs significant for guarantee power system safety and stability.Simultaneously, U.S. EPRI is had to carry out cable assessment and life-extending service abroad, for user is provided in the precise evaluation report by cable situation and degree of aging, by determining the residual life of cable, application economic means extends cable life or by excavating the latent capacity of cable, makes user postpone with cable investment 5-25.First the cable of client is checked, collect history run data and crucial sample (comprising insulation course, wire etc.), the composition (comprising physics and chemical property) of test sample book, by analyzing the risk that all these information are carried out life expectancy and continued to use this cable.

Cable is made up of core conductor, insulating material and protective seam; insulating material can be caused aging for the long-term current-carrying heating of electric current center line core conductor and outside environmental elements impact so that ultimate failure; cause short circuit initiation fire between phase line and center line or ground, accident of even blasting.According to statistics, the fire caused because of electric reason in certain year Fire in China is 31933, accounts for 26.1% of Fire in China sum, and wherein the aging fire caused of cable accounts for more than the 5O% of whole electrical fire, causes huge property loss.Therefore, carry out the forecasting research of aging life of cables caused by heat, to elimination disaster hidden-trouble, reduce fire damage and have important practical significance.

Voltage Cable Lines Construction is the combination of multiple product, be the combination of cable body, cable accessory (intermediate head, terminal etc.), cable structures (ditch, pipeline, tunnel, level bridges etc.) etc. before forming line facility, the running quality therefore forming each processing quality of finished product production link, the installation quality of fixing link and operational management link all determines to put into operation runs the final running quality of cable plant.Therefore, in production, installation, operational process, the normal condition of each link just can accomplish that the life-span running cable is normally healthy.Research cable flow process safe and stable operation to cable in life cycle management is very important basis.

Summary of the invention

Object of the present invention be exactly in order to overcome above-mentioned prior art exist defect and provide a kind of consider overall scientific, calculate accurately based on the overall life cycle cost evaluation method of power cable heat transfer model.

Object of the present invention can be achieved through the following technical solutions:

Based on an overall life cycle cost evaluation method for power cable heat transfer model, comprise the following steps:

1) cable conductor temperature is obtained according to cable conducting heat model;

2) the cable thermal life is calculated according to cable conductor temperature;

3) set up the overall life cycle cost model of high-tension cable according to cable thermal life and annual rate, calculate the uniform annuity obtaining high-tension cable, i.e. the LCC value of high-tension cable;

4) obtain the LCC value of the dissimilar high-tension cable of different manufacturers, and the cable selecting LCC value minimum is as preferred cable.

Described step 1) in, cable conducting heat model is:

I ²[RT ₁+R(1+λ ₁)T ₂]+W _d[0.5T ₁+n(T ₂+T ₃)]＝θ ₁-θ _C

R＝R'(1+Y _s+Y _p)

R'＝R ₀[1+a ₂₀(θ-20)]

$Y_S=\frac{{X_S}^4}{192+0.8{X_S}^4}$

${X_S}^2=8\mathrm{\π}f\frac{K_s}{R^{\′}}\×{10}^{-7}$

$Y_p=\frac{X_P^4}{192+0.8X_P^4}{\left(\frac{d_c}{s}\right)}^2\[0.312{\left(\frac{d_c}{s}\right)}^2+\frac{1.18}{\frac{X_P^4}{192+0.8X_P^4}+0.27}\]$

${X_P}^2=8\mathrm{\π}f\frac{K_P}{R^{\′}}\×{10}^{-7}$

$W_d={\mathrm{\ωCU}}_0^{2}tan\mathrm{\δ}$

ω＝2πf

$C=\frac{\mathrm{\ϵ}\×{10}^{-9}}{18ln\frac{D_i}{d_c}}$

$T_1=\frac{{\mathrm{\ρ}}_{T_1}}{2\mathrm{\π}}Ln(1+\frac{2t_1}{d_c})$

$T_2=\frac{{\mathrm{\ρ}}_{T_2}}{2\mathrm{\π}}Ln\[\frac{D_{oc}+2t_2}{\frac{(D_{oc}+D_{it})}{2}+t_2}\]$

$T_3=\frac{1}{{\mathrm{\πD}}_{e}h{\left(\mathrm{\Δ}\mathrm{\θ}\right)}^{0.25}}$

$h=\frac{Z}{{\left(D_e\right)}^g}+E$

Wherein, I is current-carrying capacity, and R is the conductor AC resistance under working temperature, λ ₁for sheath and shadow loss factor, determined by type of cable, W _dfor insulation dielectric loss, n is cable inner conductor radical, T ₁for insulation course thermal resistance between conductor and protective metal shell, T ₂for protective coverings of cable thermal resistance, T ₃for thermal resistance between cable surface and surrounding air, θ ₁for cable conductor temperature, θ _cfor environment temperature, R' is running temperature lower conductor direct current resistance, R ₀conductor DC resistance when being 20 DEG C, a ₂₀the temperature coefficient of copper conductor when being 20 DEG C, θ is running temperature, Y _sfor kelvin effect factor, X _sfor intermediate variable, for circular compact conductor K _s=1, segmentation round conductor K _s=0.435, f is power frequency, Y _pfor proximity effect factor, d _cfor conductor diameter, s is the spacing in each conductor axle center, U ₀for voltage-to-ground, ε is constant, gets 2.3, D _ifor outer insulation diameter, d _cfor inner screening external diameter, for insulating material thermal resistivity, d _cfor conductor diameter, t ₁for the insulation thickness between conductor and sheath, t ₂for oversheath thickness, for the thermal resistivity of nonmetal oversheath, D _ocfor the outside diameter of cable, D _itfor protective metal shell external diameter, h is coefficient of heat transfer, D _efor the outside diameter of cable, Δ θ is the cable surface temperature rise of relative ambient temperature, and E, Z, g are constant.

Described step 2) in, the calculating formula of cable thermal life a is:

$a={10}^{-10.673+5346/{\mathrm{\θ}}_1}$

Wherein, θ ₁for cable conductor temperature.

Described step 3) in, the overall life cycle cost model of high-tension cable is:

LCC＝CI+CO+CM+CF+CD

$CI={\mathrm{CI}}_b^a+{\mathrm{CI}}_f^a$

$CO={\mathrm{CO}}_b^a+{\mathrm{CO}}_f^a$

$CM={\mathrm{CM}}_b^a+{\mathrm{CM}}_f^a$

$CF={\mathrm{CF}}_b^a+{\mathrm{CF}}_f^a$

$CD={\mathrm{CD}}_b^a+{\mathrm{CD}}_f^a$

Wherein, LCC is the overall life cycle cost of high-tension cable, and CI is first Meteorological, and CO is operating cost, and CM is repair and maintenance expense, and CF is failure cost, and CD is the retired disposal costs of equipment, for the LCC value of cable body first Meteorological a, for the LCC value of cable accessory first Meteorological a, for the LCC value of cable body operating cost a, for the LCC value of cable accessory operating cost a, for the LCC value of cable body repair and maintenance expense a, for the LCC value of cable accessory repair and maintenance expense a, for the LCC value of cable body failure cost a, for the LCC value of cable accessory failure cost a, for the LCC value of cable body equipment retired disposal costs a, for the LCC value of cable accessory equipment retired disposal costs a, a is the cable thermal life.

The computing method of the LCC value of described a are:

$X_u^a=X_u^0\×\frac{i{(1+i)}^a}{\[{(1+i)}^a-1\]}$

Wherein, be the LCC value of a, be the LCC present worth of the 0th year, X value is CI, CO, CF, CM or CD, and subscript u value is that b or f, b represent cable body, and f represents cable accessory, and i is annual rate.

The computing method of the first Meteorological CI LCC present worth of the 0th year are:

${\mathrm{CI}}_u^o={\mathrm{CI}}_{uGZ}+{\mathrm{CI}}_{uAZ}+{\mathrm{CI}}_{uQT}$

CI _uGZ＝CI _uGZ1+CI _uGZ2+CI _uGZ3+CI _uGZ4+CI _uGZ5

CI _uAZ＝CI _uAZ1+CI _uAZ2+CI _uAZ3

Wherein, for the first Meteorological LCC present worth of the 0th year, CI _uGZfor purchase commodity, CI _uAZfor Installation and Debugging expense, CI _uQTfor other fees, CI _uGZ1take for buying, CI _uGZ2for specific purpose tool and first standby redundancy take, CI _uGZ3for Site Service takes, CI _uGZ4for supplier's traffic expense and related expenses of taxation, CI _uGZ5for premium of insurance, CI _uAZ1for building mounting cost, CI _uAZ2for proprietor's traffic expense, CI _uAZ3for debugging charge, subscript u value is that b or f, b represent cable body, and f represents cable accessory.

The computing method of the operating cost CO LCC present worth of the 0th year are:

${\mathrm{CO}}_b^o=\frac{{\mathrm{CO}}_b^n}{{(1+i)}^n}$

${\mathrm{CO}}_b^n={\mathrm{CO}}_{bSH}^n+{\mathrm{CO}}_{bXS}^n$

${\mathrm{CO}}_{bSH}^n=(\mathrm{\Δ}N+N)\×\mathrm{\ρ}$

$\mathrm{\Δ}N=3I_{jf}^2{r}_{0}L\stackrel{\‾}{T}\×{10}^{-3}$

$N=U^2{\mathrm{\ωC}}_{0}Ltan\mathrm{\δ}\×\stackrel{\‾}{T}\×{10}^{-3}$

${\mathrm{CO}}_{bXS}^n=({\mathrm{CO}}_{bXS1}+{\mathrm{CO}}_{bXS2}+{\mathrm{CO}}_{bXS3}+{\mathrm{CO}}_{bXS4}+{\mathrm{CO}}_{bXS5}+{\mathrm{CO}}_{bXS6}+{\mathrm{CO}}_{bXS7})\×L$

${\mathrm{CO}}_f^o=\frac{{\mathrm{CO}}_f^n}{{(1+i)}^n}$

${\mathrm{CO}}_f^n=({\mathrm{CO}}_{fHW}+{\mathrm{CO}}_{fZW})\×k$

Wherein, for the cable body operating cost LCC present worth of the 0th year, for the cable body operating cost LCC of 1 year is worth then, for annual cable loss expense, for year daily walkaround inspection expense, Δ N is year AC resistance loss of electricity, and N is year dielectric loss electricity, and ρ is cost electricity price, I _jffor rms current value, r ₀for 30 DEG C of conductor alternating current resistances of the every phase conductor unit length of cable line, L is unit length, for annual hours run, U is cable operating voltage, C ₀for the every phase mutual capacitance of cable, tan δ is the tangent value of cable insulation dielectric loss angle, CO _bXS1for environment makes an inspection tour expense, CO _bXS2for professional inspection charge, CO _bXS3for ground temperature testing cost, CO _bXS4for induction current testing expense, CO _bXS5for spy patrols expense, CO _bXS6for sampling observation expense, CO _bXS7for other expenditure, subscript n is 1 year, and subscript 0 is the 0th year, and subscript b is cable body, and subscript f is cable accessory, for the cable accessory operating cost LCC of 1 year is worth then, CO _fHWfor infrared detection is taken, CO _fZWfor UV detect takes, k is unit tricks, and i is annual rate.

The computing method of the repair and maintenance expense CM LCC present worth of the 0th year are:

${\mathrm{CM}}_b^o=\frac{{\mathrm{CM}}_b^n}{{(1+i)}^n}$

${\mathrm{CM}}_b^n=({\mathrm{CM}}_{bZQ}+{\mathrm{CM}}_{bSY})\×L$

${\mathrm{CM}}_f^o=\frac{{\mathrm{CM}}_f^n}{{(1+i)}^n}$

${\mathrm{CM}}_f^n=\frac{{\mathrm{xCM}}_{fx}}{x+y}+\frac{{\mathrm{yCM}}_{fy}}{x+y}$

Wherein, for the cable body repair and maintenance expense LCC present worth of the 0th year, for the cable body repair and maintenance expense LCC of 1 year is worth then, CM _bZQfor periodicmaintenance takes, CM _bSYfor periodic test takes, L is unit length, for the cable accessory repair and maintenance expense LCC present worth of the 0th year, for the cable accessory repair and maintenance expense LCC of 1 year is worth then, CM _fxfor single cover medial head repair and maintenance takes, CM _fyfor single locking terminal head repair and maintenance takes, x is cable mid head weight, and y is cable terminal weight, and i is annual rate.

The computing method of the failure cost CF LCC present worth of the 0th year are:

${\mathrm{CF}}_b^o=\frac{{\mathrm{CF}}_b^n}{{(1+i)}^n}$

${\mathrm{CF}}_b^n={\mathrm{CF}}_{bGJ}+{\mathrm{CF}}_{bGS}$

${\mathrm{CF}}_f^o=\frac{{\mathrm{CF}}_f^n}{{(1+i)}^n}$

${\mathrm{CF}}_f^n={\mathrm{CF}}_{fGJ}+{\mathrm{CF}}_{fGS}$

Wherein, for the cable body failure cost LCC present worth of the 0th year, for the cable body failure cost LCC of 1 year is worth then, CF _bGJfor cable body corrective maintenance costs, CF _bGSfor cable body breakdown loss takes, for the cable accessory failure cost LCC present worth of the 0th year, for the cable accessory failure cost LCC of 1 year is worth then, CF _fGJfor cable accessory corrective maintenance costs, CF _fGSfor cable accessory breakdown loss takes, i is annual rate.

The computing method of the retired disposal costs CD LCC present worth of the 0th year are:

${\mathrm{CD}}_b^o=\frac{{\mathrm{CD}}_b^a}{{(1+i)}^a}$

${\mathrm{CD}}_b^a={\mathrm{CD}}_{bTC}-{\mathrm{CD}}_{bHS}$

${\mathrm{CD}}_f^o=\frac{{\mathrm{CD}}_f^a}{{(1+i)}^a}$

${\mathrm{CD}}_f^a={\mathrm{CD}}_{fTC}-{\mathrm{CD}}_{fHS}$

Wherein, for the cable body retired disposal costs LCC present worth of the 0th year, for the LCC final value of cable body retired disposal costs a, CD _bTCfor the retired handling of cable body, CD _bHSfor cable body waste recovery expense, for the cable accessory retired disposal costs LCC present worth of the 0th year, for the LCC final value of cable accessory retired disposal costs a, CD _fTCfor the retired handling of cable accessory, CD _fHSfor cable accessory waste recovery expense, i is annual rate, and a is the cable thermal life.

Compared with prior art, the present invention has the following advantages:

First the present invention sets up the temperature that cable conducting heat model obtains cable conductor, and it is creationary by the cable conductor temperature calculating cable thermal life, and be applied in overall life cycle cost evaluation method, and the thermal life based on cable calculates the LCC value of different manufacturers different model cable accurately, instead of original is all the method assessed the cost according to unified life value, solve in overall life cycle cost is evaluated, high-tension cable different manufacturers cannot be distinguished, the problem of different quality cable life, the technical and economic performances such as the overall life cycle cost of cable can be evaluated more scientificly.

Accompanying drawing explanation

Fig. 1 is method flow diagram of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

Embodiment:

As shown in Figure 1, a kind of overall life cycle cost evaluation method based on power cable heat transfer model, comprises the following steps:

1) cable conductor temperature is obtained according to cable conducting heat model;

2) the cable thermal life is calculated according to cable conductor temperature;

3) set up the overall life cycle cost model of high-tension cable according to cable thermal life and annual rate, calculate the uniform annuity obtaining high-tension cable, i.e. the LCC value of high-tension cable;

4) obtain the LCC value of the dissimilar high-tension cable of different manufacturers, and the cable selecting LCC value minimum is as preferred cable.

In 110kV cable life cycle management, consider from difference angle, important is cable constructin phase and cable operation maintenance, overhaul and repairing and the retired link such as to scrap after breaking down.

After this project has been done to understand in depth and investigate to the operation of Shanghai Electric Power Co 110kV cable and annex thereof, maintenance, failure condition, think, 110kV cable is very similar with the Whole Course Management pattern of 220kV cable, CI, CO, CM, CF, CD general expenses in LCC computation model, 220kV cable and 110kV cable are all without substantial differences.And the quantity of 220kV cable is few, the time of putting into operation is short, and statistical sample is few, causes statistics (as failure rate) representativeness not good, may play interference effect to correct LCC model.Meanwhile, be simplified model, outstanding key issue, this project only sets up LCC model to 110kV cable.

LCC Life Cycle Cost Analysis is the basis of LCC Modeling Research.

Apply following computation model framework:

LCC＝CI+CO+CM+CF+CD

Wherein LCC refers to cable and annex thereof the total expenses in life cycle management;

CI refers to first Meteorological;

CO refers to operating cost;

CM refers to repair and maintenance expense;

CF refers to failure cost;

CD refers to the retired disposal costs of equipment.

For 110kV cable and annex thereof, the decomposition of LCC fee structure is described as follows:

Cable body LCC fee structure decomposes and calculation specifications:

Cable body calculate time, all with " rice/three-phase " for unit.Stated rate is i, and the cable body life-span is a, calculates LCC value according to CI, CO, CM, CF and CD five functional modules.

Present worth refers to the value then of the 0th end of year, and final value refers to the value then calculating time termination.

Uniform annuity=LCC present worth × i (1+i) ^a/ [(1+i) ^a-1], after calculating all module present worths, calculate uniform annuity again, namely LCC value, compares.

1, initial Meteorological CI:

Mainly comprise the purchase commodity of cable body, Installation and Debugging expense and other expenditure.Purchase commodity comprises cable body and buys expense, specific purpose tool and first standby redundancy expense, Site Service expense, supplier's traffic expense and related expenses of taxation, premium of insurance etc.; Installation and Debugging expense comprises the debugging charge before cable body construction mounting cost, proprietor's traffic expense, putting equipment in service; Other expenditure comprises other contingent expense about waiting.

Purchase commodity+Installation and Debugging expense+the other expenditure of CI=cable body

(1) purchase commodity

Purchase commodity=cable body is bought and is taken+specific purpose tool and first standby redundancy expense+Site Service expense+supplier's traffic expense and related expenses of taxation+premium of insurance

Cable body purchase commodity, based on producer's price, is the price after technology and scope of supply adjustment.

(2) Installation and Debugging expense

Installation and Debugging expense=construction mounting cost+proprietor's traffic expense+debugging charge

Installation and Debugging expense mainly cable laying mounting cost.

(3) other expenditure

The state monitoring apparatus expense etc. that other expenditure is the special debug-item expense of cable body and purchases possibly.

The value then in the 0th year calculated, i.e. present worth.

After obtaining CI present worth, then be multiplied by (1+i) ^aobtain the final value of its correspondence.

2, operating cost CO

Mainly comprise cable loss expense and day-to-day operation patrol and examine (depending on) expense.Daily walkaround inspection expense comprises tour equipment and the Master Cost of daily walkaround inspection needs and makes an inspection tour labour cost.Day-to-day operation action comprises the work such as environment is maked an inspection tour, specialty checks, ground temperature detects, induction current is tested, spy patrols, infrared detection, UV detect.

The CO=year cable loss expense+annual daily walkaround inspection expense of 1 year

Cable year wear and tear expense=cable year loss of electricity × cost electricity price=(year AC resistance loss of electricity+year dielectric loss electricity) × cost electricity price

Year AC resistance loss of electricity △ N=3Ijf2r0L × year hours run × 10-3kWh

In formula: r0 is 30 DEG C of conductor alternating current resistances of the every phase conductor unit length of cable line.

Rms current value Ijf is taken as: maximum planned load electric current × rms current coefficient=rated current × annual rate of load condensate.

L is unit length, and annual hours run gets 8760h.

Cable year dielectric loss N=U2 ω C0Ltan δ × annual hours run × 10-3kWh

In formula: U cable operating voltage, the every phase mutual capacitance of C0 cable, tan δ cable insulation dielectric loss tangent of an angle, L is unit length, and annual hours run gets 8760h, is owner and directly inputs.

Annual daily walkaround inspection expense=(environment makes an inspection tour expense+professional inspection charge+ground temperature testing cost+induction current testing expense+spy expense of patrolling+sampling observation expense+other expenditure) × unit length.

Obtain the value then of 1 year from above, and by the CO in the n-th year, be multiplied by (1+i) ^-nconversion, to the present worth of basic year, simultaneously again by the present worth of standard year, is multiplied by (1+i) ^aobtain corresponding final value.

3, repair and maintenance expense CM

Mainly comprise periodicmaintenance and testing expenses.The artificial material expense that periodicmaintenance expense needs when comprising periodicmaintenance.Content of the test comprises 3 years periodic tests once such as cable grounding resistance measurement, sheath remote measurement, local discharge test.

1 year CM=periodicmaintenance and test fee=periodic maintenance expense × unit length

Periodic maintenance is 3 years one-periods, if but one's last year be just in time 3 multiple, then there is not CM in this year.

Calculate the value then of 1 year, and by the CM in the n-th year, be multiplied by (1+i) ^-nconversion, to the present worth of basic year, simultaneously again by the present worth of standard year, is multiplied by (1+i) ^aobtain corresponding final value.

4, failure cost CF

Mainly comprise corrective maintenance costs, breakdown loss expense.Corrective maintenance costs mainly comprises inspection of fault and rehabilitation expense.Breakdown loss expense comprises interruption cost etc.

Within 1 year, CF=corrective maintenance costs+breakdown loss takes=amounts to single failure expense × failure rate × unit length

Amount to single failure expense and comprise the expense of reparation, cooperation expense, electric quantity loss expense etc., directly inputted by owner; Failure rate is the annual number of stoppages/cable installation length, considers to calculate to obtain according to producer's bid information, and owner directly inputs; Unit length is directly inputted by owner.

Calculate the value then of 1 year, and by the CF in the n-th year, be multiplied by (1+i) ^-nconversion, to the present worth of basic year, simultaneously again by the present worth of standard year, is multiplied by (1+i) ^aobtain corresponding final value.

5, retired disposal costs CD

Comprise cable body and remove expenses of environmental protection when disposing the retired process of artificial, cost of equipment and traffic expense and equipment, and the Reclaiming benefit of cable body when retired should be deducted.

CD=retired handling-waste recovery expense

Retired handling=removal cost=62% of equipment × install direct construction cost

Erected cost gets the mounting cost in CI, and retired handling is determined by budget specification.

The volume of the density × unit length copper of the unit price × copper of waste recovery expense=copper

The unit price of copper is estimated by the market price and is determined; Volume=3 π the r of unit length copper ²l, wherein, r is cable interface radius, and L is unit length.

The CD calculated is worth then, is also final value.

After obtaining CD final value, then be multiplied by (1+i) ^-aobtain the present worth of its correspondence.

Cable accessory LCC fee structure decomposes and calculation specifications:

When cable accessory calculates, all in units of cover, because of the acquisition expenses slightly difference of cable mid head and terminals, and relevant operation maintenance management, its number weight is considered when applying.

Wherein the ratio of cable mid head and terminals is according to x:y weighting weight.Stated rate is i, and the cable accessory life-span is a, calculates LCC value according to CI, CO, CM, CF and CD five functional modules.

Present worth refers to the value then of the 0th end of year, and final value refers to the value then calculating time termination.

Uniform annuity=LCC present worth × i (1+i) ^a/ [(1+i) ^a-1], after calculating all module present worths, calculate uniform annuity again, i.e. LCC value.

6, initial Meteorological CI

Mainly comprise the purchase commodity of cable accessory, Installation and Debugging expense and other expenditure.Purchase commodity comprises cable accessory and buys expense, Site Service expense, specific purpose tool and first standby redundancy expense, supplier's traffic expense and related expenses of taxation, premium of insurance etc.; Installation and Debugging expense comprises the debugging charge before cable accessory construction mounting cost, proprietor's traffic expense, putting equipment in service; Other expenditure comprises other contingent expense about waiting.

Purchase commodity+Installation and Debugging expense+the other expenditure of CI=cable accessory

(1) purchase commodity

Purchase commodity=cable accessory is bought and is taken+specific purpose tool and first standby redundancy expense+Site Service expense+supplier's traffic expense and related expenses of taxation+premium of insurance

=medial head purchase commodity × (x/ (x+y))+terminals purchase commodity × (y/ (x+y))

Cable accessory medial head and terminals purchase commodity, based on producer's price, are the expenses after technology and scope of supply adjustment.

(2) Installation and Debugging expense

Installation and Debugging expense=construction mounting cost+proprietor's traffic expense+debugging charge

Installation and Debugging expense mainly cable laying mounting cost, because of intermediate head assessment of bids together with terminals, to resit an exam worrys by number ratio when considering erected cost, as intermediate head erected cost × (x/ (x+y))+terminals erected cost × (y/ (x+y))=annex erected cost consideration.

(3) other expenditure

The state monitoring apparatus expense etc. that other expenditure is the special debug-item expense of cable accessory and purchases possibly.

Calculate the value then in the 0th year, i.e. present worth.

After obtaining CI present worth, then be multiplied by (1+i) ^aobtain the final value of its correspondence.

7, operating cost CO

Mainly comprise day-to-day operation patrol and examine (depending on) expense.Daily walkaround inspection expense comprises tour equipment and the Master Cost of daily walkaround inspection needs and makes an inspection tour labour cost.The work such as the main infrared detection of day-to-day operation action, UV detect.

CO=(infrared detection takes+UV detect expense) × unit tricks.

Calculate the value then of 1 year, and by the CO in the n-th year, be multiplied by (1+i) ^-nconversion, to the present worth of basic year, simultaneously again by the present worth of standard year, is multiplied by (1+i) ^aobtain corresponding final value.

8, repair and maintenance expense CM

Mainly comprise periodicmaintenance and testing expenses.The artificial material expense that periodicmaintenance expense needs when comprising periodicmaintenance is 3 years periodic tests once.

Within 1 year, CM=mono-cover medial head repair and maintenance takes × (x/ (x+y))+mono-locking terminal head repair and maintenance expense × (y/ (x+y))

Periodic maintenance is 3 years one-periods, if single one's last year is just in time the multiple of 3, then this year CM does not occur.

Calculate the value then of 1 year, and by the CM in the n-th year, be multiplied by (1+i) ^-nconversion, to the present worth of basic year, simultaneously again by the present worth of standard year, is multiplied by (1+i) a and obtains corresponding final value.

9, failure cost CF

Mainly comprise corrective maintenance costs, breakdown loss expense.Corrective maintenance costs mainly comprises inspection of fault and rehabilitation expense.Breakdown loss expense comprises interruption cost etc.

Within 1 year, CF=corrective maintenance costs+breakdown loss takes=amounts to single failure expense × failure rate × unit tricks

Amount to single failure expense and comprise reparation expense, failure costs etc., directly inputted by owner; Failure rate is that tricks installed by the annual number of stoppages/cable, considers to calculate to obtain according to producer's bid information.

Calculate the value then of 1 year, and by the CF in the n-th year, be multiplied by (1+i) ^-nconversion, to the present worth of basic year, simultaneously again by the present worth of standard year, is multiplied by (1+i) ^aobtain corresponding final value.

10, retired disposal costs CD

Comprise cable body and remove expenses of environmental protection when disposing the retired process of artificial, cost of equipment and traffic expense and equipment, and the Reclaiming benefit of cable accessory when retired should be deducted.

CD=retired handling-waste recovery expense

Retired handling=the removal cost of equipment=mono-cover medial head demolition expense × (x/ (x+y))+mono-locking terminal head demolition expense × (y/ (x+y))

Erected cost gets the mounting cost in CI, and retired handling is determined by budgetary estimate.

Waste recovery expense is very little, ignores.

The CD calculated is worth then, is also final value.

After obtaining CD final value, then be multiplied by (1+i) ^-aobtain the present worth of its correspondence.

Life-span is the key factor that equipment LCC analyzes.The life-span of electrical equipment generally comprises electric life, mechanical life, thermal life.For crosslinked cable, relative maturity can application life achievement in research be the thermal life.Researching and analysing of thermal life for 110kV cable, will be done in this part.

Even if meet relevant cables technical standard, still there is difference more or less in the insulating material performance (thermal resistivity) of different manufacturers cable, conductor resistance value, each Rotating fields size.The difference of resistance value can cause the difference of cable loss in operation, and then causes the difference of cable temperature rise.The difference of the crosslinked polyethylene of cable, the thermal resistivity of jacket material, can cause the difference of cable heat transfer property in running, and then cause the difference of cable temperature rise.The difference of cable temperature rise in operation, can cause the difference of the thermal life of cable major insulation crosslinked polyethylene

Cable conducting heat model is:

I ²[RT ₁+R(1+λ ₁)T ₂]+W _d[0.5T ₁+n(T ₂+T ₃)]＝θ ₁-θ _C

R＝R'(1+Y _s+Y _p)

R'＝R ₀[1+a ₂₀(θ-20)]

$Y_S=\frac{{X_S}^4}{192+0.8{X_S}^4}$

${X_S}^2=8\mathrm{\π}f\frac{K_s}{R^{\′}}\×{10}^{-7}$

$Y_p=\frac{X_P^4}{192+0.8X_P^4}{\left(\frac{d_c}{s}\right)}^2\[0.312{\left(\frac{d_c}{s}\right)}^2+\frac{1.18}{\frac{X_P^4}{192+0.8X_P^4}+0.27}\]$

${X_P}^2=8\mathrm{\π}f\frac{K_P}{R^{\′}}\×{10}^{-7}$

$W_d={\mathrm{\ωCU}}_0^{2}tan\mathrm{\δ}$

ω＝2πf

$C=\frac{\mathrm{\ϵ}\×{10}^{-9}}{18ln\frac{D_i}{d_c}}$

$T_1=\frac{{\mathrm{\ρ}}_{T_1}}{2\mathrm{\π}}Ln(1+\frac{2t_1}{d_c})$

$T_2=\frac{{\mathrm{\ρ}}_{T_2}}{2\mathrm{\π}}Ln\[\frac{D_{oc}+2t_2}{\frac{(D_{oc}+D_{it})}{2}+t_2}\]$

$T_3=\frac{1}{{\mathrm{\πD}}_{e}h{\left(\mathrm{\Δ}\mathrm{\θ}\right)}^{0.25}}$

$h=\frac{Z}{{\left(D_e\right)}^g}+E$

Wherein, I is current-carrying capacity, and R is the conductor AC resistance under working temperature, λ ₁for sheath and shadow loss factor, determined by type of cable, W _dfor insulation dielectric loss, n is cable inner conductor radical, T ₁for insulation course thermal resistance between conductor and protective metal shell, T ₂for protective coverings of cable thermal resistance, T ₃for thermal resistance between cable surface and surrounding air, θ ₁for cable conductor temperature, θ _cfor environment temperature, R' is running temperature lower conductor direct current resistance, R ₀conductor DC resistance when being 20 DEG C, a ₂₀the temperature coefficient of copper conductor when being 20 DEG C, θ is running temperature, Y _sfor kelvin effect factor, X _sfor intermediate variable, for circular compact conductor K _s=1, segmentation round conductor K _s=0.435, f is power frequency, Y _pfor proximity effect factor, d _cfor conductor diameter, s is the spacing in each conductor axle center, U ₀for voltage-to-ground, ε is constant, gets 2.3, D _ifor outer insulation diameter, d _cfor inner screening external diameter, for insulating material thermal resistivity, d _cfor conductor diameter, t ₁for the insulation thickness between conductor and sheath, t ₂for oversheath thickness, for the thermal resistivity of nonmetal oversheath, D _ocfor the outside diameter of cable, D _itfor protective metal shell external diameter, h is coefficient of heat transfer, D _efor the outside diameter of cable, Δ θ is the cable surface temperature rise of relative ambient temperature, and E, Z, g are constant.

The calculating formula of cable thermal life a is:

$a={10}^{-10.673+5346/{\mathrm{\θ}}_1}$

Wherein, θ ₁for cable conductor temperature.

The Computing Principle of cable thermal life is: the insulating material performance (thermal resistivity) of different manufacturers cable, conductor resistance value, each Rotating fields size exist certain difference.The difference of resistance value can cause the difference of cable loss in operation, and then causes the difference of cable temperature rise.The difference of the crosslinked polyethylene of cable, the thermal resistivity of jacket material, can cause the difference of cable heat transfer property in running, also can cause the difference of cable temperature rise.The difference of cable temperature rise in operation, can cause the difference of the thermal life of cable major insulation crosslinked polyethylene.

According to above principle, we, according to cable temperature rise test result, establish the conducting heat model of cable; Then have chosen the long-time running current value of 630mm2 and 800mm2 O. cable, calculate the cable thermal life under this electric current.

This participates in 7 units of LCC commercial evaluation of tenders, in the cable sampling observation in 2008 of Shanghai Electric Power Co, has carried out temperature rise test to wherein 5 producers's (Shandong Luneng, Hangzhou Hua Xin, upper cable Teng Cang, Qingdao Chinese cable, Shenyang Furukawa); All the other 2 producers, have 1 (Hangzhou cable) not have temperature rise test result to utilize; Other 1 (Chongqing energy) provides temperature rise test data in tender documents, but it is variant that test condition and Shanghai Electric Power Co inspect temperature rise test by random samples, comparability and the equivalence of test findings are poor, so will not adopt this assessment of bids of temperature rise test data of this producer; According to the principle formulated before the assessment of bids, thermal life of these 2 producers (Chongqing energy, Hangzhou cable) adopts and enters the identical value of the minimum producer of Shanghai Power Network safety requirements with having reached in this assessment of bids.

When LCC calculates, not only consider cable and the initial acquisition expenses of annex thereof, also will consider the factors such as its operating cost, product reliability, repair and maintenance expense.This LCC assessment of bids shows that original equipment cost (product tender price) is not the single factor determining Life Cycle Cost, performance is good, the product of failure rate is low, although acquisition expenses is higher than the product of poor performance (failure rate is high), but after LCC computational analysis, its in life cycle management expense lower than the high product of failure rate.If also consider the difference of the thermal lifetime of different manufacturers cable in addition, then the cable product LCC expense of perfect heat-dissipating can be lower.

When applying the LCC assessment of bids, some problems are also had to should be noted that:

First be the accumulation to equipment use performance, operation maintenance data, the accuracy lacked affecting LCC calculating of data, thus will have a data accumulative process.This LCC assessment of bids is doing detailed investigation to cable at daily production run maintenance activity before, has done detailed decomposition to cable Life Cycle Cost, for good basis is laid in this LCC assessment of bids.

Next be the depth of investigation of manufacturing plant in reliability design and the reliability disadvantages of data is provided.Occurring in this assessment of bids that some producers are zero to its hazard rate report, be not inconsistent with actual conditions, by adopting Reliability Analysis, giving to revise according to the statistics that Shanghai Electric Power Co is grasped to related data.

Also have many technical research needs to complete in addition, such as available rate is predicted for matured product available statistical data, but for new product, how to determine that available rate is a problem.Current reference average level processes related data.

Difference between original equipment Management System and the management of LCC theory is still needed and to be eliminated by the break-in of long period, and LCC management itself also has and constantly improves process.

The LCC management of electric system is that on the basis of reliability, make the life-cycle of equipment or system have cost be minimum management.Sectoral lines is broken in LCC management, is considered as a whole by the cost of the different phases such as planning, design, capital construction, operation, with enterprise-wide benefit for starting point, seeks preferred plan; Consider all expenses that can occur, seeking balance between suitable available rate and use in full, find out the scheme that LCC is minimum; And the feature of overall process considers from planning and design to the whole life cycle of scrapping.As in equipment purchase, it is not only the purchasing price of consideration equipment, and more to consider the support cost of equipment in whole life cycle management, comprise installation, operation, maintenance, transformation, upgrade until the overall process of scrapping, its core content carries out analytical calculation to the LCC of equipment or system, carries out decision-making with quantized value.

This project is by the combing to flow process in cable total life cycle, according to company's cable operation characteristic, introduce daily operation management situation related data, each stage expense in the life cycle of measuring and calculating unit length cable, as the important foundation data of LCC modeling, computational analysis; Meanwhile, this project has carried out systematic analysis with regard to the cable body thermal life, establishes cable conducting heat model, makes it to combine with LCC analytical model, perfect LCC model; LCC method is applied in cable bidding, forms practical application demonstration and the success experience of cable LCC management, achieve the unification of economy and reliability in Strategic purchasing, also promoted LCC technology and management application in-depth simultaneously.

Claims (10)

1., based on an overall life cycle cost evaluation method for power cable heat transfer model, it is characterized in that, comprise the following steps:

1) cable conductor temperature is obtained according to cable conducting heat model;

2) the cable thermal life is calculated according to cable conductor temperature;

3) set up the overall life cycle cost model of high-tension cable according to cable thermal life and annual rate, calculate the uniform annuity obtaining high-tension cable, i.e. the LCC value of high-tension cable;

4) obtain the LCC value of the dissimilar high-tension cable of different manufacturers, and the cable selecting LCC value minimum is as preferred cable.

2. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 1, is characterized in that, described step 1) in, cable conducting heat model is:

I ²[RT ₁+R(1+λ ₁)T ₂]+W _d[0.5T ₁+n(T ₂+T ₃)]＝θ ₁-θ _C

R＝R'(1+Y _s+Y _p)

R'＝R ₀[1+a ₂₀(θ-20)]

$Y_S=\frac{{X_S}^4}{192+0.8{X_S}^4}$

${X_S}^2=8\mathrm{\π}f\frac{K_s}{R^{\′}}\×{10}^{-7}$

$Y_p=\frac{X_P^4}{192+0.8X_P^4}{\left(\frac{d_c}{s}\right)}^2\[0.312{\left(\frac{d_c}{s}\right)}^2+\frac{1.18}{\frac{X_P^4}{192+0.8X_P^4}+0.27}\]$

${X_P}^2=8\mathrm{\π}f\frac{K_P}{R^{\′}}\×{10}^{-7}$

$W_d={\mathrm{\ωCU}}_0^{2}tan\mathrm{\δ}$

ω＝2πf

$C=\frac{\mathrm{\ϵ}\×{10}^{-9}}{18ln\frac{D_i}{d_c}}$

$T_1=\frac{{\mathrm{\ρ}}_{T_1}}{2\mathrm{\π}}Ln(1+\frac{2t_1}{d_c})$

$T_2=\frac{{\mathrm{\ρ}}_{T_2}}{2\mathrm{\π}}Ln\[\frac{D_{oc}+2t_2}{\frac{(D_{oc}+D_{it})}{2}+t_2}\]$

$T_3=\frac{1}{{\mathrm{\πD}}_{e}h{\left(\mathrm{\Δ}\mathrm{\θ}\right)}^{0.25}}$

$h=\frac{Z}{{\left(D_e\right)}^g}+E$

Wherein, I is current-carrying capacity, and R is the conductor AC resistance under working temperature, λ ₁for sheath and shadow loss factor, determined by type of cable, W _dfor insulation dielectric loss, n is cable inner conductor radical, T ₁for insulation course thermal resistance between conductor and protective metal shell, T ₂for protective coverings of cable thermal resistance, T ₃for thermal resistance between cable surface and surrounding air, θ ₁for cable conductor temperature, θ _cfor environment temperature, R' is running temperature lower conductor direct current resistance, R ₀conductor DC resistance when being 20 DEG C, a ₂₀the temperature coefficient of copper conductor when being 20 DEG C, θ is running temperature, Y _sfor kelvin effect factor, X _sfor intermediate variable, for circular compact conductor K _s=1, segmentation round conductor K _s=0.435, f is power frequency, Y _pfor proximity effect factor, d _cfor conductor diameter, s is the spacing in each conductor axle center, U ₀for voltage-to-ground, ε is constant, gets 2.3, D _ifor outer insulation diameter, d _cfor inner screening external diameter, for insulating material thermal resistivity, d _cfor conductor diameter, t ₁for the insulation thickness between conductor and sheath, t ₂for oversheath thickness, for the thermal resistivity of nonmetal oversheath, D _ocfor the outside diameter of cable, D _itfor protective metal shell external diameter, h is coefficient of heat transfer, D _efor the outside diameter of cable, Δ θ is the cable surface temperature rise of relative ambient temperature, and E, Z, g are constant.

3. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 1, is characterized in that, described step 2) in, the calculating formula of cable thermal life a is:

$a={10}^{-10.673+5346/{\mathrm{\θ}}_1}$

Wherein, θ ₁for cable conductor temperature.

4. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 1, is characterized in that, described step 3) in, the overall life cycle cost model of high-tension cable is:

LCC＝CI+CO+CM+CF+CD

$CI={\mathrm{CI}}_b^a+{\mathrm{CI}}_f^a$

$CO={\mathrm{CO}}_b^a+{\mathrm{CO}}_f^a$

$CM={\mathrm{CM}}_b^a+{\mathrm{CM}}_f^a$

$CF={\mathrm{CF}}_b^a+{\mathrm{CF}}_f^a$

$CD={\mathrm{CD}}_b^a+{\mathrm{CD}}_f^a$

Wherein, LCC is the overall life cycle cost of high-tension cable, and CI is first Meteorological, and CO is operating cost, and CM is repair and maintenance expense, and CF is failure cost, and CD is the retired disposal costs of equipment, for the LCC value of cable body first Meteorological a, for the LCC value of cable accessory first Meteorological a, for the LCC value of cable body operating cost a, for the LCC value of cable accessory operating cost a, for the LCC value of cable body repair and maintenance expense a, for the LCC value of cable accessory repair and maintenance expense a, for the LCC value of cable body failure cost a, for the LCC value of cable accessory failure cost a, for the LCC value of cable body equipment retired disposal costs a, for the LCC value of cable accessory equipment retired disposal costs a, a is the cable thermal life.

5. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 4, it is characterized in that, the computing method of the LCC value of described a are:

$X_u^a=X_u^0\×\frac{i{(1+i)}^a}{\[{(1+i)}^a-1\]}$

Wherein, be the LCC value of a, be the LCC present worth of the 0th year, X value is CI, CO, CF, CM or CD, and subscript u value is that b or f, b represent cable body, and f represents cable accessory, and i is annual rate.

6. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 5, is characterized in that, the computing method of the first Meteorological CI LCC present worth of the 0th year are:

${\mathrm{CI}}_u^o={\mathrm{CI}}_{uGZ}+{\mathrm{CI}}_{uAZ}+{\mathrm{CI}}_{uQT}$

CI _uGZ＝CI _uGZ1+CI _uGZ2+CI _uGZ3+CI _uGZ4+CI _uGZ5

CI _uAZ＝CI _uAZ1+CI _uAZ2+CI _uAZ3

Wherein, for the first Meteorological LCC present worth of the 0th year, CI _uGZfor purchase commodity, CI _uAZfor Installation and Debugging expense, CI _uQTfor other fees, CI _uGZ1take for buying, CI _uGZ2for specific purpose tool and first standby redundancy take, CI _uGZ3for Site Service takes, CI _uGZ4for supplier's traffic expense and related expenses of taxation, CI _uGZ5for premium of insurance, CI _uAZ1for building mounting cost, CI _uAZ2for proprietor's traffic expense, CI _uAZ3for debugging charge, subscript u value is that b or f, b represent cable body, and f represents cable accessory.

7. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 5, is characterized in that, the computing method of the operating cost CO LCC present worth of the 0th year are:

${\mathrm{CO}}_b^o=\frac{{\mathrm{CO}}_b^n}{{(1+i)}^n}$

${\mathrm{CO}}_b^n={\mathrm{CO}}_{bSH}^n+{\mathrm{CO}}_{bXS}^n$

${\mathrm{CO}}_{bSH}^n=(\mathrm{\Δ}N+N)\×\mathrm{\ρ}$

$\mathrm{\Δ}N=3I_{jf}^2{r}_{0}L\stackrel{\‾}{T}\×{10}^{-3}$

$N=U^2{\mathrm{\ωC}}_{0}Ltan\mathrm{\δ}\×\stackrel{\‾}{T}\×{10}^{-3}$

${\mathrm{CO}}_{bXS}^n=({\mathrm{CO}}_{bXS1}+{\mathrm{CO}}_{bXS2}+{\mathrm{CO}}_{bXS3}+{\mathrm{CO}}_{bXS4}+{\mathrm{CO}}_{bXS5}+{\mathrm{CO}}_{bXS6}+{\mathrm{CO}}_{bXS7})\×L$

${\mathrm{CO}}_f^o=\frac{{\mathrm{CO}}_f^n}{{(1+i)}^n}$

${\mathrm{CO}}_f^n=({\mathrm{CO}}_{fHW}+{\mathrm{CO}}_{fZW})\×k$

Wherein, for the cable body operating cost LCC present worth of the 0th year, for the cable body operating cost LCC of 1 year is worth then, for annual cable loss expense, for year daily walkaround inspection expense, Δ N is year AC resistance loss of electricity, and N is year dielectric loss electricity, and ρ is cost electricity price, I _jffor rms current value, r ₀for 30 DEG C of conductor alternating current resistances of the every phase conductor unit length of cable line, L is unit length, and T is annual hours run, and U is cable operating voltage, C ₀for the every phase mutual capacitance of cable, tan δ is the tangent value of cable insulation dielectric loss angle, CO _bXS1for environment makes an inspection tour expense, CO _bXS2for professional inspection charge, CO _bXS3for ground temperature testing cost, CO _bXS4for induction current testing expense, CO _bXS5for spy patrols expense, CO _bXS6for sampling observation expense, CO _bXS7for other expenditure, subscript n is 1 year, and subscript 0 is the 0th year, and subscript b is cable body, and subscript f is cable accessory, for the cable accessory operating cost LCC of 1 year is worth then, CO _fHWfor infrared detection is taken, CO _fZWfor UV detect takes, k is unit tricks, and i is annual rate.

8. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 5, is characterized in that, the computing method of the repair and maintenance expense CM LCC present worth of the 0th year are:

${\mathrm{CM}}_b^o=\frac{{\mathrm{CM}}_b^n}{{(1+i)}^n}$

${\mathrm{CM}}_b^n=({\mathrm{CM}}_{bZQ}+{\mathrm{CM}}_{bSY})\×L$

${\mathrm{CM}}_f^o=\frac{{\mathrm{CM}}_f^n}{{(1+i)}^n}$

${\mathrm{CM}}_f^n=\frac{{\mathrm{xCM}}_{fx}}{x+y}+\frac{{\mathrm{yCM}}_{fy}}{x+y}$

Wherein, for the cable body repair and maintenance expense LCC present worth of the 0th year, for the cable body repair and maintenance expense LCC of 1 year is worth then, CM _bZQfor periodicmaintenance takes, CM _bSYfor periodic test takes, L is unit length, for the cable accessory repair and maintenance expense LCC present worth of the 0th year, for the cable accessory repair and maintenance expense LCC of 1 year is worth then, CM _fxfor single cover medial head repair and maintenance takes, CM _fyfor single locking terminal head repair and maintenance takes, x is cable mid head weight, and y is cable terminal weight, and i is annual rate.

9. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 5, is characterized in that, the computing method of the failure cost CF LCC present worth of the 0th year are:

${\mathrm{CF}}_b^o=\frac{{\mathrm{CF}}_b^n}{{(1+i)}^n}$

${\mathrm{CF}}_b^n={\mathrm{CF}}_{bGJ}+{\mathrm{CF}}_{bGS}$

${\mathrm{CF}}_f^o=\frac{{\mathrm{CF}}_f^n}{{(1+i)}^n}$

${\mathrm{CF}}_f^n={\mathrm{CF}}_{fGJ}+{\mathrm{CF}}_{fGS}$

Wherein, for the cable body failure cost LCC present worth of the 0th year, for the cable body failure cost LCC of 1 year is worth then, CF _bGJfor cable body corrective maintenance costs, CF _bGSfor cable body breakdown loss takes, for the cable accessory failure cost LCC present worth of the 0th year, for the cable accessory failure cost LCC of 1 year is worth then, CF _fGJfor cable accessory corrective maintenance costs, CF _fGSfor cable accessory breakdown loss takes, i is annual rate.

10. a kind of overall life cycle cost evaluation method based on power cable heat transfer model according to claim 5, is characterized in that, the computing method of the retired disposal costs CD LCC present worth of the 0th year are:

${\mathrm{CD}}_b^o=\frac{{\mathrm{CD}}_b^a}{{(1+i)}^a}$

${\mathrm{CD}}_b^a={\mathrm{CD}}_{bTC}-{\mathrm{CD}}_{bHS}$

${\mathrm{CD}}_f^o=\frac{{\mathrm{CD}}_f^a}{{(1+i)}^a}$

${\mathrm{CD}}_f^a={\mathrm{CD}}_{fTC}-{\mathrm{CD}}_{fHS}$

Wherein, for the cable body retired disposal costs LCC present worth of the 0th year, for the LCC final value of cable body retired disposal costs a, CD _bTCfor the retired handling of cable body, CD _bHSfor cable body waste recovery expense, for the cable accessory retired disposal costs LCC present worth of the 0th year, for the LCC final value of cable accessory retired disposal costs a, CD _fTCfor the retired handling of cable accessory, CD _fHSfor cable accessory waste recovery expense, i is annual rate, and a is the cable thermal life.