CN109444540B - The alternating current-direct current resistance ratio of laminated insulation conductor determines the current-carrying capacity appraisal procedure of method and laminated insulation conductor cable - Google Patents
The alternating current-direct current resistance ratio of laminated insulation conductor determines the current-carrying capacity appraisal procedure of method and laminated insulation conductor cable Download PDFInfo
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Abstract
The alternating current-direct current resistance ratio that the present invention discloses a kind of laminated insulation conductor determines the current-carrying capacity appraisal procedure of method and laminated insulation conductor cable, by studying other structures conductor sample SrWith ksBetween existing linear relationship, according to laminated insulation conductor can measure calculate SrThe anti-k for pushing away laminated insulation conductorsValue, and then for the calculating of the alternating current-direct current resistance ratio of laminated insulation conductor and current-carrying capacity assessment.The AC resistance that can be used for laminated insulation conductor calculates, and convenience of calculation is quick, can provide theoretical foundation for the optimization design and service check of laminated insulation conductor.The present invention can carry out current-carrying capability assessment to laminated insulation conductor cable simultaneously, ensure the accuracy of carrying current calculation result, because of current-carrying capacity deviation bring Transmission Cost when reducing conductor application.
Description
Technical field
The present invention relates to transmission line of electricity, power cable current-carrying capability studying technological domain, especially a kind of laminated insulation is led
The alternating current-direct current resistance ratio of body determines the current-carrying capacity appraisal procedure of method and laminated insulation conductor cable.
Background technique
Kelvin effect is also known as skin effect, refers to when alternating current passes through conductor, since induction effect causes conductor to cut
Current distribution is uneven on face, a kind of bigger phenomenon of closer conductor surface current density.This phenomenon claims " kelvin effect ".Collection
Skin effect increases the effective resistance of conductor, and when low-frequency current flows through thin wire, kelvin effect can without a moment's thought, but frequency is got over
High, the bigger kelvin effect of cross-sectional area of conductor more be can not ignore.Especially in 800mm2Collection in above electric cable with large cross-section conductor
Skin effect is the main reason for causing AC resistance to be substantially higher than D.C. resistance.
Submarine cable power transmission engineering is the important component of networking project construction in domain over strait, crosslinked polyetylene insulated exchange
Submarine cable has many advantages, such as that transmission capacity is high, easy for installation, simple without the limitation of laying drop, operation and maintenance, because due to substantially
Replace the oil-filled submarine cable of the first generation.Submarine cable because conductor to be taken blocks water measure can not when cable conductor section is larger
Adopting an effective measure reduces kelvin effect and kindred effect, and AC resistance maximum can reach the 160% of D.C. resistance, causes to cut greatly
The running wastage of face submarine cable is larger.
Technology of the laminated insulation conductor due to taking enameled wire Yu naked copper monofilament layer-stranding, so as to reduce conductor
AC resistance is effectively reduced in kelvin effect.But there is not the alternating current of document report laminated insulation conductor so far
The calculation method of resistance.Although alternating current-direct current resistance ratio can be tested to obtain by AC resistance, current test method disunity, as a result
Accuracy it is still to be tested.Such as according to traditional measurement method, with 1800mm2For conductor, then AC resistance will be overestimated
16%, while alternating current-direct current resistance ratio is the basic data for calculating current-carrying capacity of cable, once it is inaccurate, it will be unable to the volume for knowing cable
Surely current-carrying capacity is run, current-carrying capacity is meaned the reduction of grid power transmission efficiency by underestimating, and the electric energy conveyed in the unit time is reduced, made
At waste of energy, economy of transmitting electricity is reduced and Transmission Cost improves.Therefore the alternating current-direct current resistance ratio theory meter of laminated insulation conductor
Calculation just seems necessary.
Summary of the invention
The object of the present invention is to provide a kind of alternating current-direct current resistance ratios of laminated insulation conductor to determine that method and laminated insulation are led
The current-carrying capacity appraisal procedure of body cable, the AC resistance that can be used for laminated insulation conductor calculate, and convenience of calculation is quick, can be layering
The optimization design and service check of insulated electric conductor provide theoretical foundation.The present invention can carry laminated insulation conductor cable simultaneously
Flow capability evaluation, ensure carrying current calculation result accuracy, reduce conductor application when because current-carrying capacity deviation bring transmission of electricity at
This.
The technical scheme adopted by the invention is as follows: a kind of alternating current-direct current resistance ratio of laminated insulation conductor determines method, comprising:
S1 obtains the S of multiple conductor samplesrAnd ksData, SrFor the ratio of conductor radial direction DC conductance and axial DC conductance
Value, ksFor the correction factor of conductor kelvin effect factor；
S2, the S based on multiple conductor samplesrAnd ksData, using least square method to SrWith ksLinear fit is carried out, is obtained
To SrWith ksFunctional relation；
S3 calculates its S for the laminated insulation conductor of alternating current-direct current resistance ratio to be determinedrTheoretical value；
S4, according to SrWith ksFunctional relation, be based on SrTheoretical value calculates ksTheoretical value；
S5, based on the k being calculatedsTheoretical value calculates kelvin effect factor；
S6 calculates the alternating current-direct current resistance ratio of laminated insulation conductor based on the kelvin effect factor being calculated.
With reference in IEC60287-1-1 standard, for the k of unlike material different structure conductorsEmpirical value is recommended, when us
Think same cross-sectional area, the k of the conductor of different structure formsThe difference of value, when from the difference of conductor radial surface conductance,
The S to other structures conductor sample can then be passed throughrWith ksRelationship come the anti-k for pushing away laminated insulation conductorsValue, and then can be used for point
The alternating current-direct current resistance ratio of layer insulated electric conductor calculates and current-carrying capacity assessment.
Preferably, in S1, the conductor sample includes full enameled wire monofilament stranded conductor and naked copper monofilament stranded conductor.
Since laminated insulation conductor is the intertwist body of naked copper monofilament and enamel-cover monofilament, therefore the k of laminated insulation conductorsIt is twisted with full enamel-cover monofilament
Close the k of conductor and naked copper monofilament stranded conductorsCorrelation it is larger, the S obtained using both conductor samplesrWith ksLetter
It is practical that number relationship is also better able to fitting laminated insulation conductor.
Preferably, in S1, the S of conductor samplerValue is actual test value, the k of conductor samplesValue calculates according to the following formula
It obtains:
Wherein,Kelvin effect factor, R are surveyed for conductor sampleaccFor the test of conductor sample AC resistance
Value, R'cFor conductor sample D.C. resistance test value；β is intermediate parameters, andF is conductor sample work
Make electric voltage frequency, conductor sample D.C. resistance when R' is 20 DEG C.SrActual test value is that conductor sample radial direction DC conductance is surveyed
The ratio of examination value and axial DC conductivity test value, specific test method are to take one section of conductor sample, remove the oxygen of conductive surface
Change layer and wrapped semi-conductive layer expose conductor, then tests the radial DC conductance and axial DC conductance of this section of conductor respectively,
Then the ratio of the two is calculated.
Preferably, in S2, SrWith ksLinear relationship are as follows: ks=l+q × Sr, wherein l is least square linear fit
Intercept, q are the slope of least square linear fit.
Preferably, in S3, the laminated insulation conductor of the alternating current-direct current resistance ratio to be determined, SrTheoretical value calculation formula
Are as follows:
Wherein, α1For SrThe correction factor of theoretical value and measured value, n are the radical of naked copper monofilament in laminated insulation conductor, m
Indicate the radical of enamel-cover monofilament.
In the present invention, correction factor α1Value range is between 0~1 preferably 0.55.According to the reality in CIGRE file
Measured data is chosen, for correcting SrDeviation between calculated value and measured value, for preferably empirical value.
Preferably, in S5, the kelvin effect factor of laminated insulation conductor are as follows:
Wherein, xs 2For intermediate parameters, and
In S6, ignore kindred effect, the alternating current-direct current resistance ratio of laminated insulation conductor to be determined i.e.:
Rac/Rdc=1+ys (9)
Wherein, RacFor the AC resistance of laminated insulation conductor, RdcFor the D.C. resistance of laminated insulation conductor, can correspond to not
Same running temperature directly measures respectively.When such as 20 DEG C, D.C. resistance Rdc=R0', then when having 20 DEG C, Rac=R0'·(1+ys)。
Invention additionally discloses the laminated insulations that a kind of alternating current-direct current resistance ratio based on aforementioned laminated insulation conductor determines method
Conductor cable current-carrying capacity appraisal procedure, comprising:
Method is determined using the alternating current-direct current resistance ratio of aforementioned laminated insulation conductor, determines the alterating and direct current of laminated insulation conductor
Resistance ratio；
D.C. resistance and fixed alternating current-direct current resistance ratio based on laminated insulation conductor calculate laminated insulation conductor electricity
The AC resistance of cable；
The electric energy loss of laminated insulation conductor cable is calculated, electric energy loss includes dielectric loss, protective metal shell loss factor
With loss induced by armour factor；
The thermal resistance of laminated insulation conductor cable is calculated, thermal resistance includes insulation thermal resistance, liner layer or separation sleeve thermal resistance, and outer
Sheath thermal resistance；
AC resistance, electric energy loss and thermal resistance based on the laminated insulation conductor cable being calculated assess laminated insulation
The current-carrying capacity of conductor cable.
The prior art can be used for the calculating of various electric energy losses and thermal resistance in the present invention respectively.
Preferably, for the laminated insulation conductor cable laid in ocean bottom soil, the current-carrying capacity I calculation formula of cable are as follows:
Wherein, Δ θcFor the temperature difference of conductor maximum operating temperature and environment temperature, WdFor dielectric loss, T1 is insulation thermal resistance,
T2 is liner layer or separation sleeve thermal resistance, and T3 is outer jacket thermal resistance, and T4 is ocean bottom soil thermal resistance, Rac' it is conductor maximum operating temperature
Under AC resistance；λ 1 is protective metal shell loss factor, and λ 2 is loss induced by armour factor.
According to formula Rac/Rdc=1+ys, there is Rac'=Rdc'(1+ys), then Rdc' be maximum operating temperature under direct current
Resistance.Conductor runs on maximum temperature θcUnder D.C. resistance Rdc' are as follows:
Rdc'=R0'×[1+α×(θc-20)] (11)
Wherein, α is conductor temperature coefficient, for copper conductor, according to IEC-287-1-1 standard, α=0.00393/ DEG C.Before
Text has been described, at 20 DEG C, the D.C. resistance R of laminated insulation conductor0' can directly measure.
Beneficial effect
Laminated insulation conductor alternating current-direct current resistance ratio of the present invention determines method, overcome existing method can not accurate evaluation contain
The defect of laminated insulation conductor cable current-carrying capacity.Method process convenience of calculation can carry out the laminated insulation conductor in design fast
The theoretical calculation of the alternating current-direct current resistance ratio of speed, provides theoretical foundation for the optimization design and service check of laminated insulation conductor.
Meanwhile the present invention is based on laminated insulation conductor alternating current-direct current resistance ratios to determine method, the laminated insulation conductor electricity of proposition
Cable current-carrying capacity appraisal procedure, so that laminated insulation conductor can accurately obtain the current-carrying of theoretical calculation when being applied to power cable
Data are measured, and then embody the saving energy and decreasing loss effect of laminated insulation conductor, efficiently utilize laminated insulation conductor electric for user
The high current-carrying capacity of cable provides theoretical foundation, can avoid losing caused by due to current-carrying capacity waste.
Detailed description of the invention
Fig. 1 show laminated insulation conductor alternating current-direct current resistance ratio determination of the present invention and current-carrying capacity appraisal procedure schematic diagram；
Fig. 2 show laminated insulation conductor structure schematic diagram；
Fig. 3 show ksWith SrMatched curve schematic diagram.
Specific embodiment
It is further described below in conjunction with the drawings and specific embodiments.
Refering to what is shown in Fig. 1, laminated insulation conductor is also referred to as saving energy and decreasing loss conductor, it is twisted by multilayer monofilament, by
Each layer is successively twisted naked copper monofilament and enamel-cover monofilament outside to inside, and wherein outermost layer is naked copper monofilament.
The method of the present invention is based on it is assumed hereinafter that carrying out:
1. enamel-cover single line paint film during conductor strand is not damaged；
2. film thickness is negligible compared to filament diameter；
3. resistance value increase caused by AC resistance kelvin effect occupies main cause, therefore this compared to D.C. resistance
Kindred effect is ignored in the calculating of invention AC resistance.
In the calculating of the conductor AC resistance in IEC60287-1-1 standard, provide simplified based on theoretical model
The AC resistance calculation formula of circle copper stranded conductor:
R=R'(1+ys+yp)(1)
Copper conductor D.C. resistance when R' is 20 DEG C, ysFor skin effect coefficient, ypFor approach effect coefficient.Ignore and closes on effect
It answers, then formula changes are as follows:
R=R'(1+ys)(2)
Wherein, kelvin effect is because of ysAre as follows:
xs 2For intermediate parameters, andFor conventional conductor, given in IEC60287-1-1 standard
Correction factor ksRecommendation, but unconventional laminated insulation conductor is not provided, therefore the friendship of laminated insulation conductor
Leakage resistance can not be acquired according to formula (1) or formula (2).
The present invention is directed to the kelvin effect factor correction coefficient ks to laminated insulation conductorsIt is studied, and then seeks being layered
The kelvin effect factor of insulated electric conductor, so that it is determined that the AC resistance ratio of laminated insulation conductor.
With reference in IEC60287-1-1 standard, for the k of unlike material different structure conductorsEmpirical value is recommended.When us
Think same cross-sectional area, the k of the conductor of different structure formsThe difference of value, when from the difference of conductor radial surface conductance,
The S to other structures conductor sample can then be passed throughrWith ksRelationship come the anti-k for pushing away laminated insulation conductorsValue, and then can be used for point
The alternating current-direct current resistance ratio of layer insulated electric conductor calculates and current-carrying capacity assessment.
The present invention is by a large amount of basic datas the study found that the kelvin effect factor correction coefficient k of conductors, with conductor table
Face diameter is to the ratio S between conductance and twisted single line self-conductancerBetween there is certain linear relationship, therefore the present invention is logical
Cross research conductor sample ksWith SrBetween relation curve, and then by can measure calculate laminated insulation conductor structural parameters Sr,
Obtain the kelvin effect factor correction coefficient k of laminated insulation conductors, the alternating current-direct current resistance of laminated insulation conductor finally can be obtained
Than.
Embodiment 1
The present embodiment is that a kind of alternating current-direct current resistance ratio of laminated insulation conductor determines method, comprising:
S1 obtains the S of multiple conductor samplesrAnd ksData, SrFor the ratio of conductor radial direction DC conductance and axial DC conductance
Value, ksFor the correction factor of conductor kelvin effect factor.
The conductor sample includes full enameled wire monofilament stranded conductor and naked copper monofilament stranded conductor.Due to laminated insulation
Conductor is the intertwist body of naked copper monofilament and enamel-cover monofilament, therefore the k of laminated insulation conductorsWith full enamel-cover monofilament stranded conductor and naked
The k of copper monofilament stranded conductorsCorrelation it is larger, the S obtained using both conductor samplesrWith ksFunctional relation also more
It is practical that laminated insulation conductor can be bonded.
The S of the conductor samplerValue is actual test value, as conductor sample radial direction DC conductance test value and axial straight
Galvanic electricity leads the ratio of test value.
The k of the conductor samplesValue is calculated according to the following formula:
Wherein,Kelvin effect factor, R are surveyed for conductor sampleaccFor the test of conductor sample AC resistance
Value, R'cFor conductor sample D.C. resistance test value；β is intermediate parameters, andF is conductor sample work
Make electric voltage frequency, conductor sample D.C. resistance when R' is 20 DEG C.
S2, the S based on multiple conductor samplesrAnd KsData, using least square method to SrWith ksLinear fit is carried out, is obtained
To SrWith ksFunctional relation.
Refering to what is shown in Fig. 2, setting SrWith ksLinear relationship are as follows: ks=l+q × Sr, wherein l is quasi- for least square linear
The intercept of conjunction, q are the slope of least square linear fit.Bring the S of conductor sample intorWith ksTaking for l and q can be obtained in data
Value.The present invention is fitted to obtain through actual curve: ks=0.245+0.967 × Sr。
S3 calculates its S for the laminated insulation conductor of alternating current-direct current resistance ratio to be determinedrTheoretical value.
For laminated insulation conductor, SrTheoretical formula are as follows:
Wherein, a indicates that monofilament is naked copper monofilament, and b indicates that monofilament is enamel-cover monofilament, and c indicates adjacent one, two monofilament and is
Naked copper monofilament, a number of combinations for enamel-cover monofilament, d indicate that adjacent two monofilament are the number of combinations of naked copper monofilament, e table
Showing that adjacent two monofilament are the number of combinations of enamel-cover monofilament, n indicates that the radical of naked copper monofilament, m indicate the radical of enamel-cover monofilament,
γaaIndicate surface radial direction conductance when adjacent two monofilament are naked copper monofilament, γbbIndicate that adjacent two monofilament are enamel-cover
Surface radial direction conductance when monofilament, γabIndicate that adjacent one, two monofilament is naked copper monofilament, a surface for enamel-cover monofilament
Radial conductance, γcuIndicate the twisted single line conductance of copper conductor monofilament.
Since the paint film insulation resistance of enamel-cover single line is higher, it is believed that it is completely insulated, therefore γab=γbb=0, and by dividing
Layer insulated electric conductor structure is it is found that d=n, γaa=γcu+γjc, γjc< < γcu.Simultaneously using multiplied by correction factor α1Side
Method, the difference of revised theory calculated value and measured value.Then practical SrCalculation formula are as follows:
Wherein, α1For SrThe correction factor of theoretical value and measured value, value range are between 0~1 preferably 0.55.
S4, according to SrWith ksFunctional relation, be based on SrTheoretical value calculates ksTheoretical value；The relationship obtained in conjunction with step S2
Curve, formula i.e.:
S5, based on the k being calculatedsTheoretical value calculates the kelvin effect factor of laminated insulation conductor are as follows:
Wherein, xs 2For intermediate parameters, and
S6 calculates the alternating current-direct current resistance ratio of laminated insulation conductor based on the kelvin effect factor being calculated.
Ignore kindred effect, the alternating current-direct current resistance ratio of laminated insulation conductor to be determined i.e.:
Rac/Rdc=1+ys (9)
Wherein, RacFor the AC resistance of laminated insulation conductor, RdcFor the D.C. resistance of laminated insulation conductor, can correspond to not
Same running temperature directly measures respectively.When such as 20 DEG C, D.C. resistance Rdc=R0', then when having 20 DEG C, Rac=R0'·(1+ys)。
Embodiment 2
The present embodiment is the laminated insulation that method is determined based on the alternating current-direct current resistance ratio of laminated insulation conductor described in embodiment 1
Conductor cable current-carrying capacity appraisal procedure, comprising:
Method is determined using the alternating current-direct current resistance ratio of 1 laminated insulation conductor of embodiment, determines that the friendship of laminated insulation conductor is straight
Leakage resistance ratio；
D.C. resistance and fixed alternating current-direct current resistance ratio based on laminated insulation conductor calculate laminated insulation conductor electricity
The AC resistance of cable；
The electric energy loss of laminated insulation conductor cable is calculated, electric energy loss includes dielectric loss, protective metal shell loss factor
With loss induced by armour factor；
The thermal resistance of laminated insulation conductor cable is calculated, thermal resistance includes insulation thermal resistance, liner layer or separation sleeve thermal resistance, and outer
Sheath thermal resistance；
AC resistance, electric energy loss and thermal resistance based on the laminated insulation conductor cable being calculated assess laminated insulation
The current-carrying capacity of conductor cable.
The prior art can be used for the calculating of various electric energy losses and thermal resistance in the present invention respectively.
For the laminated insulation conductor cable laid in ocean bottom soil, the current-carrying capacity I calculation formula of cable are as follows:
Wherein, Δ θcFor the temperature difference of conductor maximum operating temperature and environment temperature, WdFor dielectric loss, T1 is insulation thermal resistance,
T2 is liner layer or separation sleeve thermal resistance, and T3 is outer jacket thermal resistance, and T4 is ocean bottom soil thermal resistance, Rac' it is conductor maximum operating temperature
Under AC resistance；λ 1 is protective metal shell loss factor, and λ 2 is loss induced by armour factor.
According to formula Rac/Rdc=1+ys, there is Rac'=Rdc'(1+ys), then Rdc' be maximum operating temperature under direct current
Resistance.Conductor runs on maximum temperature θcUnder D.C. resistance Rdc' are as follows:
Rdc'=R0'×[1+α×(θc-20)] (11)
Wherein, α is conductor temperature coefficient, for copper conductor, according to IEC-287-1-1 standard, α=0.00393/ DEG C.Before
Text has been described, at 20 DEG C, the D.C. resistance R of laminated insulation conductor0' can directly measure.
Embodiment 3
The present embodiment is assessed using the current-carrying capacity that the method for embodiment 1 and embodiment 2 carries out laminated insulation conductor cable.
One, primary condition
1.1, laminated insulation conductor cable structure size is determined are as follows:
1.2, overhead cabling method, environmental condition and operation conditions are determined:
Cable runs on three-phase alternating current system；Rated operational voltage is 500kV；Maximum operating temperature θ when operationcIt is 90
℃；Environment temperature, that is, ocean bottom soil temperature θ0It is 20 DEG C；Seabed direct-burried buried depth l is 2500mm；Ocean bottom soil thermal resistivity ρ e is
0.7；Land direct-burried buried depth l' is 1000mm；Land soil thermal resistivity ρ e' is 1.0；Cable laying spacing are as follows: marine interval S1
For 50000mm, soil medium spacing S on the bank2For 10000mm.
Two, laminated insulation conductor alternating current-direct current resistance ratio and AC resistance calculate
2.1, the laminated insulation conductor DC resistance under maximum temperature calculates
The D.C. resistance (Ω/m) of conductor is R at 20 DEG C0', it can directly measure；Conductor temperature factor alpha takes 0.00393/ DEG C,
Then according to the D.C. resistance of formula (11) maximum operating temperature lower conductor are as follows:
Rdc'=R0'×[1+0.00393×(θc-20)]
2.2, the laminated insulation conductor AC resistance under maximum temperature calculates
With reference to Fig. 1, the structural parameters of layering insulation stranded conductor are as follows:
| Copper monofilament radical (n) | Enamel-cover monofilament radical (m) | Filament diameter | Sectional area |
| 88 | 66 | 4mm | 1800mm2 |
Method, the S that least square fitting obtains are determined according to the alternating current-direct current resistance ratio of embodiment 1rWith ksFunctional relation
Are as follows:
To the laminated insulation conductor of Fig. 1 structure, S can be calculated in n=88, m=66r=0.31, and then k is calculateds
=0.55.
Y can be obtained using formula (8)s=0.14.The friendship of the layering insulation stranded conductor of Fig. 1 structure when therefore can calculate 20 DEG C
D.C. resistance ratio are as follows:
Rac/R0'=1+ys=1.14
The AC resistance R of 20 DEG C of layered insulating twisted conductorsacFor 0.0115 Ω/km, same conductor and operating condition
Under, the AC resistance of the 20 DEG C of layered insulating twisted conductors obtained using conventional method is 0.0138 Ω/km.
2.3, the laminated insulation conductor AC resistance under maximum temperature calculates, formula are as follows:
Rac'=Rdc'(1+ys)
Three, the electric energy loss of laminated insulation conductor cable is calculated
3.1, dielectric loss WdIt calculates
Known: power supply angular frequency (rad/s) is the π f of ω=2, and voltage-to-ground (phase voltage) is U=290 × 105V, insulation material
The dielectric coefficient (being derived from IEC-287-1-1) of material is ε=2.3, and the dielectric loss angle tangent of insulating materials (is derived from IEC-287-1-
It 1) is δ=0.0005 tg, cable capacitance per unit length isThen every phase
The loss of unit length cable dielectric are as follows:
Wd=ω c (U0)2δ=2.24764 tan (W/m)
3.2, the loss factor λ 1 of cable metal sheath and armouring, λ 2 are calculated
3.2.1 the calculating of protective metal shell (lead set) resistance
The resistivity of lead set is s=21.4 × 10 ρ at known 20 DEG C-8(Ω/m), temperature-coefficient of electrical resistance αs=0.004
(1/ DEG C), maximum operating temperature θs=θc× 0.8 (DEG C), shielding sectional area are As=π dstl·10-6=π (Dt_1+
tl)·tl·10-6=1.606 × 10-3(m2), then under operating temperature protective metal shell resistance are as follows:
3.2.2 the calculating of armouring (copper wire) resistance
The resistivity of copper wire is ρ at known 20 DEG Ccu'=1.75 × 10-8(Ω/m), temperature-coefficient of electrical resistance αcu=
0.00393 (1/ DEG C), maximum operating temperature θa=θ c0.7 (DEG C), shielding sectional area are Acu=θ a2·0.7854·n1·
10-6=2.205 × 10-3(m2), then under operating temperature armouring copper wire resistance are as follows:
3.2.3 the calculating of metallic sheath and armouring parallel resistance Rs
3.2.4 the calculating of metallic sheath and loss induced by armour
Since actual metallic sheath and armor are in parallel, computed losses are by the loss conversion of armor to metallic sheath
Merge calculating.
Equivalent diameter d=0.5 × (Dt_1+Dih)=128.3mm, reactanceTransreactance Xm=2 ω 10-7Ln (2)=4.35 × 10-5Ω, it is intermediate
Parameter P=X+Xm,Then metallic sheath loss factor are as follows:
R is the conductor AC resistance under operating temperature, is equally calculated using the method for embodiment 1.And then it can count
Calculation obtains λ 1=0.526.Due to armor loss conversion to metallic sheath, so armor loss is zero, i.e. λ 2=0.
Four, the calculating of thermal resistance
The calculating of 4.1 insulation thermal resistance T1
Known crosslinked polyethylene thermal resistivity is ρT1=3.5Km/W, conductor diameter dc=50.2mm, insulation thickness are
Ti=34.2mm, then insulation thermal resistance T1 are as follows:
T1=(ρT1/ 2 π) ln (1+2ti/dc)=0.4792Km/W
The calculating of 4.2 liner layers or separation sleeve thermal resistance T2
Known polyethylene thermal resistivity is ρT2=3.5Km/W, armor outer diameter are dg=166.5mm, liner layer thickness
For tn=11.2mm, then liner layer thermal resistance T2 are as follows:
T2=(ρT2/2π)·ln[1+2tn/dg]
The calculating of 4.3 outer jacket thermal resistance T3
Known PE/ pitch thermal resistivity is ρT3=6.0Km/W, armor outer diameter are Dg=166.5mm, and the outside diameter of cable is
Dj=174.5mm, outer jacket is with a thickness of te=4.0mm, and armor is with a thickness of tg=6.0mm, then serving thermal resistance are as follows:
T3=(ρT3/ 2 π) ln [1+2 × te/Dj]=0.04669Km/W
Five, the calculating and assessment of current-carrying capacity
For the cable laid in ocean bottom soil
The thermal resistivity ρ e=0.7Km/W of known ocean bottom soil, the laying buried depth L=2500mm of submarine cable, laying
Environment temperature θ0=20 DEG C, soil thermal resistance calculation intermediate parameters μ=2L/De=28.539, conductor maximum operating temperature and environment
The temperature difference θ of temperaturec=θc-θ0=70 DEG C, ocean bottom soil thermal resistance is T4=ρ e/2 π × (ln (2 μ))=0.514Km/W；Generation
Enter carrying current calculation formula:
The present embodiment passes through actual measurement and calculating, and obtaining laminated insulation conductor cable current-carrying capacity is about 1978A, and is utilized
The current-carrying capacity for the same hierarchical level insulated electric conductor cable that conventional method is calculated is only 1802A, and it was verified that the present invention calculates
Obtained current-carrying capacity is without departing from actual conditions.
It can be seen that the present invention is based on the alterating and direct currents of laminated insulation conductor compared with traditional current-carrying capacity appraisal procedure
Resistance proposes that current-carrying capacity appraisal procedure is more acurrate than determining method, so that laminated insulation conductor cable is used in actual use, full
Rated current-carrying capacity 10% can be improved in the case of sufficient cable maximum operating temperature.Transmission power is allowed to calculate public affairs according to transmission line of electricity
Formula:
S=UIcos θ
Wherein, U is route voltage rating, and I is that route allows highest to convey electric current, and cos θ is line power factor.Namely
In the case of same cable structure investment, based on current-carrying capacity assessment result of the invention, cable can be supported to convey 10% electric energy more,
Especially for vast capacity extra high voltage network, significant economic benefit will be generated.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, without departing from the technical principles of the invention, several improvement and deformations can also be made, these improvement and deformations
Also it should be regarded as protection scope of the present invention.
Claims (10)
1. a kind of alternating current-direct current resistance ratio of laminated insulation conductor determines method, it is characterized in that: including:
S1 obtains the S of multiple conductor samplesrAnd ksData, SrFor the ratio of conductor radial direction DC conductance and axial DC conductance, ks
For the correction factor of conductor kelvin effect factor；
S2, the S based on multiple conductor samplesrAnd ksData, using least square method to SrWith ksLinear fit is carried out, S is obtainedrWith
ksFunctional relation；
S3 calculates its S for the laminated insulation conductor of alternating current-direct current resistance ratio to be determinedrTheoretical value；
S4, according to SrWith ksFunctional relation, be based on SrTheoretical value calculates ksTheoretical value；
S5, based on the k being calculatedsTheoretical value calculates kelvin effect factor；
S6 calculates the alternating current-direct current resistance ratio of laminated insulation conductor based on the kelvin effect factor being calculated.
2. according to the method described in claim 1, it is characterized in that: the conductor sample includes that full enameled wire monofilament is twisted in S1
Conductor and naked copper monofilament stranded conductor.
3. according to the method described in claim 1, it is characterized in that: in S1, the S of conductor samplerValue is actual test value, conductor sample
The k of productsValue is calculated according to the following formula:
Wherein,Kelvin effect factor, R are surveyed for conductor sampleaccFor conductor sample AC resistance test value,
R'cFor conductor sample D.C. resistance test value；β is intermediate parameters, andF is conductor sample work electricity
Voltage-frequency rate, conductor sample D.C. resistance when R' is 20 DEG C.
4. according to the method described in claim 1, it is characterized in that: in S2, SrWith ksLinear relationship are as follows: ks=l+q × Sr,
In, l is the intercept of least square linear fit, and q is the slope of least square linear fit.
5. according to the method described in claim 1, it is characterized in that: in S3, the laminated insulation of the alternating current-direct current resistance ratio to be determined
Conductor, SrTheoretical value calculation formula are as follows:
Wherein, α1For SrThe correction factor of theoretical value and measured value, n are the radical of naked copper monofilament in laminated insulation conductor, and m is indicated
The radical of enamel-cover monofilament.
6. according to the method described in claim 5, it is characterized in that: correction factor α1Value is 0.55.
7. according to the method described in claim 1, it is characterized in that: in S5, the kelvin effect factor of laminated insulation conductor are as follows:
Wherein, xs 2For intermediate parameters, and
In S6, ignore kindred effect, the alternating current-direct current resistance ratio of laminated insulation conductor to be determined i.e.:
Rac/Rdc=1+ys (9)
Wherein, RacFor the AC resistance of laminated insulation conductor, RdcFor the D.C. resistance of laminated insulation conductor.
8. determining that the laminated insulation of method is led based on the alternating current-direct current resistance ratio of any one of the claim 1-7 laminated insulation conductor
Body current-carrying capacity of cable appraisal procedure, characterized in that include:
Using the method for any one of claim 1-7, the alternating current-direct current resistance ratio of laminated insulation conductor is determined；
D.C. resistance and fixed alternating current-direct current resistance ratio based on laminated insulation conductor calculate laminated insulation conductor cable
AC resistance；
The electric energy loss of laminated insulation conductor cable is calculated, electric energy loss includes dielectric loss, protective metal shell loss factor and armour
Fill loss factor；
The thermal resistance of laminated insulation conductor cable is calculated, thermal resistance includes insulation thermal resistance, liner layer or separation sleeve thermal resistance and outer jacket
Thermal resistance；
AC resistance, electric energy loss and thermal resistance based on the laminated insulation conductor cable being calculated assess laminated insulation conductor
The current-carrying capacity of cable.
9. according to the method described in claim 8, it is characterized in that: laminated insulation conductor cable for being laid in ocean bottom soil,
The current-carrying capacity I calculation formula of cable are as follows:
Wherein, Δ θcFor the temperature difference of conductor maximum operating temperature and environment temperature, WdFor dielectric loss, T1 is insulation thermal resistance, and T2 is
Liner layer or separation sleeve thermal resistance, T3 are outer jacket thermal resistance, and T4 is ocean bottom soil thermal resistance, Rac' under conductor maximum operating temperature
AC resistance；λ 1 is protective metal shell loss factor, and λ 2 is loss induced by armour factor.
10. according to the method described in claim 9, it is characterized in that: conductor runs on maximum temperature θcUnder D.C. resistance Rdc'
Are as follows:
Rdc'=R0'×[1+α×(θc-20)] (11)
Wherein, α is conductor temperature coefficient, R0' be 20 DEG C of layered insulated electric conductors D.C. resistance.
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| CN113884826B (en) * | 2021-09-07 | 2024-07-02 | 中国能源建设集团江苏省电力设计院有限公司 | Direct-current cable current-carrying capacity determining method with metal sheath serving as return line |
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