CN104731898A - 10-kV three-core cable finite element thermal analysis method - Google Patents

Abstract

The invention discloses a 10-kV three-core cable finite element thermal analysis method. The method comprises the steps of 1, determining the geometric structure, size and material parameters of a 10-kV three-core cable; 2, utilizing the Solid Works for building a three-dimensional model according to the geometric structure of the 10-kV three-core cable; 3, importing the three-dimensional model built by the Solid Works into ANSYS and converting the three-dimensional model into a geometric model in the ANSYS; 4, calculating the heat production rate of a heating portion according to the current loaded by the cable and parameters of the heating portion of the cable; 5, loading material parameters of layers in the ANSYS, dividing units and applying loads to obtain the temperature field distribution result of the 10-kV three-core cable. According to the 10-kV three-core cable finite element thermal analysis method, the three-dimensional model building function of the Solid Works and the finite element analysis function of the ANSYS are combined, three-dimensional temperature field simulation of the 10-kV three-core cable is achieved, the operational process is visual and convenient, the model is precise and reliable, the operation efficiency is high, and the method can be popularized in finite element thermal analysis of complex structures like cable intermediate connectors.

Description

A kind of 10kV triple cable finite element thermal analysis method

Technical field

The present invention relates to the technical field of 10kV triple cable, refer in particular to a kind of 10kV triple cable finite element thermal analysis method.

Background technology

10kV triple cable is widely used in urban power distribution network and powers.Along with electricity need load increases day by day, the capacity requirement of power distribution network is more and more higher, and the current-carrying capacity problem of power distribution network cable is very important.IEC standard for calculating current-carrying capacity of cable has superposed multiple severe operation conditions, make the current-carrying capacity that calculates so low that to be difficult to meet workload demand, power supply department is had to abandon the current-carrying capacity restriction that IEC criterion calculation obtains and is dispatched for a long time, causes power distribution network operation and management inferior capabilities.The key factor of restriction current-carrying capacity of cable is the heating of cable, in order to determine the current-carrying capacity of 10kV triple cable, making full use of its current capacity, studying its Heating mechanism, calculate its thermo parameters method most important.

Finite element method, as the good numerical computation method of a kind of adaptability, is widely used in the numerical solution of field.Two-dimensional temperature field emulation is carried out in the cross section of the usual power taking cable of existing research, and for geometric configuratioies such as cable intermediate joints in axially inconsistent structure, two-dimensional simulation cannot obtain temperature field result accurately.Therefore, set up three-dimensional model and carry out finite element analysis to the thermo parameters method accurately determining cable and various power distribution network parts, understand the weak link of restriction power distribution network current-carrying capacity, make full use of current-carrying capacity of cable and there is important directive significance.

Summary of the invention

The object of the invention is to solve the labyrinth being difficult to modeling in ANSYS and carry out finite element thermal analysis, in order to solve the distribution in triple cable interior three-dimensional temperature field, a kind of simple 10kV triple cable finite element thermal analysis method is provided, the D modeling function utilizing SolidWorks powerful sets up the three-dimensional model of triple cable, by data-interface model imported in ANSYS and carry out finite element thermal analysis, solve triple cable three-dimensional temperature field.

For achieving the above object, technical scheme provided by the present invention is: a kind of 10kV triple cable finite element thermal analysis method, comprises the following steps:

1) geometry of 10kV triple cable, size, material parameter is determined;

2) SolidWorks is utilized to carry out three-dimensional modeling according to the geometry of 10kV triple cable;

3) three-dimensional model that SolidWorks sets up is imported ANSYS and the geometric model be converted in ANSYS;

4) according to electric current and the electric cable heating partial parameters of cable loading, heating part heat production rate is calculated;

5) in ANSYS, load layers of material parameter, division unit imposed load, solve and obtain 10kV triple cable thermo parameters method result.

In step 1) in, mainly determine the interior external radius of the core of 10kV triple cable, interior semi-conductive layer, insulation course, outer semiconducting layer, copper shield, packed layer, inner sheath, armouring, each layer of oversheath, and need determine the temperature conductivity of layers of material and need to determine temperature conductivity, specific heat capacity, the density of layers of material for Transient calculation for stable state calculating.

In step 2) in, utilize SolidWorks software, carry out modeling according to 1/3rd of symmetric theory power taking cable radial direction in thermal conduction study, as follows:

2.1) to the modeling one by one of each Rotating fields of 10kV triple cable, wherein, core, inner semiconductor layer, insulation course, outer semiconductor layer, copper shield get radial half, and packed layer, inner sheath, armor, oversheath get radial 1/3rd modelings;

2.2) by step 2.1) in set up each layer model of obtaining and assemble in newly-built assembly, the 10kV triple cable three-dimensional model that radial direction gets 1/3rd can be obtained.

In step 3) in, the triple cable three-dimensional model utilizing the data-interface of ANSYS to be set up by SolidWorks imports ANSYS and the geometric model be converted in ANSYS, as follows:

3.1) in SolidWorks, cable model assembly is exported as " x_t " formatted file;

3.2) in ANSYS, select Utility Menu>File>ImportGreatT.GreaT .GTPARA ..., select step 3.1) and middle " x_t " formatted file of deriving;

3.3) in ANSYS, select Utility Menu>PlotCtrls>StyleGreatT.G reaT.GTSolid Model Facets, select Normal Faceting in the choice box ejected after, hit OK is determined;

3.4) click right in ANSYS display interface, selects Replot;

3.5) in ANSYS, select Main Menu>Preprocessor>ModelingGr eatT.GreaT.GTOperate>Glue>Vo lum, each Rotating fields is successively selected to attempt bonding, until the success of model integrated bond, namely complete the foundation of ANSYS geometric model.

In step 4) in, comprise following calculating:

4.1) every phase proportion of goods damageds

The unit length direct current resistance of conductor under its maximum operating temperature:

R′＝R ₀×[1+α ₂₀(θ-20)]

In formula, R ₀the direct current resistance of conductor when being 20 DEG C, α ₂₀the temperature coefficient of material when being 20 DEG C, the maximum operating temperature that θ gets conductor is 90 DEG C;

The unit length AC resistance R=R ' (1+y of conductor under its maximum operating temperature _s+ y _p), wherein, kelvin effect factor:

$y_s=\frac{x_s^4}{192+0.8x_s^4}$

$x_s^2=\frac{8\mathrm{\πf}}{R^{\′}}\×{10}^{-7}{k}_s,$ K _sgetting empirical value is 1

Proximity effect factor:

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

$x_p^2=\frac{8\mathrm{\πf}}{R^{\′}}\×{10}^{-7}{k}_p,$ K _pgetting empirical value is 0.8

In formula, d _cfor conductor diameter, s is the distance between each conductor axle center;

Every phase conductor heat production rate can be obtained by following formula:

$Q=\frac{I^2{R}_l}{V}=\frac{I^{2}R}{S}=\frac{I^{2}R}{\mathrm{\π}{r}^2}$

In formula, r is cross-sectional area of conductor radius;

4.2) calculating of insulation course loss

The electric capacity of unit length cable:

$c=\frac{\mathrm{\ϵ}}{18\ln \left(\frac{D_i}{d_c}\right)}\×{10}^{-9}$

In formula, ε is insulating material dielectric coefficient, D _ifor insulation course diameter (except screen layer), d _cfor conductor diameter (having screen layer then to comprise screen layer);

The insulation loss of every middle unit length cable is mutually obtained by following formula:

$W_d=\mathrm{\ω}\·c\·U_0^2\·\mathrm{tg\δ}$

In formula, U ₀for voltage-to-ground (phase voltage), tg δ is insulation loss factor under power-supply system and working temperature;

4.3) loss of metal screen layer and armouring is calculated

The loss factor of metal screen layer is:

${\mathrm{\λ}}_1=\frac{R_s}{R}\frac{1.5}{1+{(R_s/X)}^2}=\frac{R_s}{R}\frac{1.5}{1+{(R_s/2\mathrm{\ω}{10}^{-7}\ln \left(\frac{2s}{d}\right))}^2}$

In formula, R _sfor the resistance of cable unit length metallic sheath under maximum operating temperature, a _sfor the sectional area of metallic sheath; η is the ratio of metallic sheath temperature counter conductor temperature, gets 0.8;

After trying to achieve metal screen layer loss factor, then armouring heat production rate is:

Q ₁＝λ ₁Q

For armouring, hysteresis loss coefficient:

${\mathrm{\λ}}_2^{\′}=\frac{S^2{K}^2\×{10}^{-7}}{R{d}_A\mathrm{\δ}}$

In formula, S is each conductor distance of shaft centers from, d _afor armouring mean diameter, A is armouring cross-sectional area, and δ is armouring equivalent thickness, $\mathrm{\δ}=\frac{A}{\mathrm{\π}{d}_A};K=\frac{1}{1+\frac{d_A}{\mathrm{\μ\δ}}};$

Eddy current loss factor:

${\mathrm{\λ}}_2^{\′\′}=\frac{2.25S^2{K}^2\mathrm{\δ}\×{10}^{-8}}{R\·d_A}$

Armor loss is magnetic hysteresis loss and eddy current loss sum, that is:

λ ₂＝λ′ ₂+λ″ ₂

Then armouring heat production rate is:

Q ₂＝λ ₂Q。

In step 5) in, layers of material parameter is loaded in ANSYS, geometric model can be converted to finite element model by division unit, and loaded load also solves and obtains each node temperature of finite element model, solving result is shown as cloud atlas and can understands the field distribution of triple cable internal temperature intuitively.

Compared with prior art, tool has the following advantages and beneficial effect in the present invention:

1, the invention provides a kind of 10kV triple cable finite element thermal analysis method utilizing SolidWorks and ANSYS to combine, utilize the method, 10kV triple cable distribution of three-dimensional temperature can be obtained, understanding cable inner heat heat dissipating state directly perceived, provides theoretical foundation for making full use of current-carrying capacity of cable;

2, the present invention uses that SolidWorks's set up cable geometric model, modeling process intuitive and convenient, and the model utilizing the geometrical-restriction relation of SolidWorks to set up is accurately reliable, is convenient to amendment, significantly alleviates modeling work amount;

3, method used in the present invention can be used for cable intermediate joint, the finite element thermal analysis of the inconsistent parts of the axial arrangement such as sleeve pipe, compensate for conventional two-dimensional simulation cannot this base part of accurate analysis, and is not easy to the shortcoming setting up complex geometric models in ANSYS, has practical value widely.

Accompanying drawing explanation

Fig. 1 a is cross-section of cable sketch.

Fig. 1 b is the cable model figure after having assembled.

Fig. 2 a is geometric model figure model being imported ANSYS and obtain after reconstruction.

Fig. 2 b is division unit and the finite element model figure obtained after loaded load.

Fig. 2 c is 50 DEG C for applying skin temperature, the heat production rate cloud atlas calculated when heat generating parts loading current is 400A.

Embodiment

Below in conjunction with specific embodiment, the invention will be further described.

10kV triple cable finite element thermal analysis method described in the present embodiment, its principle be solve temperature field in thermal conduction study can according to symmetry, get triple cable radial direction 1/3rd analyze, divisional plane does the process of adiabatic face, solving result is by identical with solving the integrally-built temperature field obtained, this disposal route effectively can shorten the time of solving, and reduces allocation of computer demand.Its concrete condition is as follows:

1) geometry of 10kV triple cable, size, material parameter is determined, comprise the interior external radius of the core of 10kV triple cable, interior semi-conductive layer, insulation course, outer semiconducting layer, copper shield, packed layer, inner sheath, armouring, each layer of oversheath, calculate for stable state and need the temperature conductivity determining layers of material, need for Transient calculation temperature conductivity, specific heat capacity, the density of determining layers of material.

2) utilize SolidWorks software, carry out modeling according to 1/3rd of symmetric theory power taking cable radial direction in thermal conduction study, as follows:

2.1) in SolidWorks, set up part, draw the sketch in cable 1/3rd cross section according to the structure of triple cable, as shown in Figure 1a;

2.2) set up the three-dimensional model of each Rotating fields by the stretch characteristic of SolidWorks one by one, the model of every one deck is considered as a kind of part;

2.3) in SolidWorks, set up assembly, according to the structure of triple cable by step 2.2) in all part combination of setting up get up, become the overall three-dimensional model of triple cable, as shown in Figure 1 b.

3) the triple cable three-dimensional model utilizing the data-interface of ANSYS to be set up by SolidWorks imports ANSYS and the geometric model be converted in ANSYS, as follows:

3.1) in SolidWorks, cable model assembly is exported as " x_t " formatted file;

3.2) in ANSYS, select Utility Menu>File>ImportGreatT.GreaT .GTPARA ..., select step 3.1) and middle " x_t " formatted file of deriving;

3.3) in ANSYS, select Utility Menu>PlotCtrls>StyleGreatT.G reaT.GTSolid Model Facets, select Normal Faceting in the choice box ejected after, hit OK is determined;

3.4) click right in ANSYS display interface, selects Replot;

3.5) in ANSYS, select Main Menu>Preprocessor>ModelingGr eatT.GreaT.GTOperate>Glue>Vo lum, each Rotating fields is successively selected to attempt bonding, until the success of model integrated bond, namely the foundation of ANSYS geometric model is completed, as shown in Figure 2 a.

4) according to electric current and the electric cable heating partial parameters (considering the condition such as kelvin effect, running temperature) of cable loading, calculate heating part heat production rate, comprise following calculating:

4.1) every phase proportion of goods damageds

The unit length direct current resistance of conductor under its maximum operating temperature:

R′＝R ₀×[1+α ₂₀(θ-20)]

In formula, R ₀the direct current resistance of conductor when being 20 DEG C, α ₂₀the temperature coefficient of material when being 20 DEG C, the maximum operating temperature that θ gets conductor is 90 DEG C;

The unit length AC resistance R=R ' (1+y of conductor under its maximum operating temperature _s+ y _p), wherein, kelvin effect factor:

$y_s=\frac{x_s^4}{192+0.8x_s^4}$

$x_s^2=\frac{8\mathrm{\πf}}{R^{\′}}\×{10}^{-7}{k}_s,$ K _sgetting empirical value is 1

Proximity effect factor:

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

$x_p^2=\frac{8\mathrm{\πf}}{R^{\′}}\×{10}^{-7}{k}_p,$ K _pgetting empirical value is 0.8

In formula, d _cfor conductor diameter, s is the distance between each conductor axle center;

Every phase conductor heat production rate can be obtained by following formula:

$Q=\frac{I^2{R}_l}{V}=\frac{I^{2}R}{S}=\frac{I^{2}R}{\mathrm{\π}{r}^2}$

In formula, r is cross-sectional area of conductor radius;

4.2) calculating of insulation course loss

The electric capacity of unit length cable:

$c=\frac{\mathrm{\ϵ}}{18\ln \left(\frac{D_i}{d_c}\right)}\×{10}^{-9}$

In formula, ε is insulating material dielectric coefficient, D _ifor insulation course diameter (except screen layer), d _cfor conductor diameter (having screen layer then to comprise screen layer);

The insulation loss of every middle unit length cable is mutually obtained by following formula:

$W_d=\mathrm{\ω}\·c\·U_0^2\·\mathrm{tg\δ}$

In formula, U ₀for voltage-to-ground (phase voltage), tg δ is insulation loss factor under power-supply system and working temperature;

4.3) loss of metal screen layer and armouring is calculated

The loss factor of metal screen layer is:

${\mathrm{\λ}}_1=\frac{R_s}{R}\frac{1.5}{1+{(R_s/X)}^2}=\frac{R_s}{R}\frac{1.5}{1+{(R_s/2\mathrm{\ω}{10}^{-7}\ln \left(\frac{2s}{d}\right))}^2}$

In formula, R _sfor the resistance of cable unit length metallic sheath under maximum operating temperature, a _sfor the sectional area of metallic sheath; η is the ratio of metallic sheath temperature counter conductor temperature, gets 0.8;

After trying to achieve metal screen layer loss factor, then armouring heat production rate is:

Q ₁＝λ ₁Q

For armouring, hysteresis loss coefficient:

${\mathrm{\λ}}_2^{\′}=\frac{S^2{K}^2\×{10}^{-7}}{R{d}_A\mathrm{\δ}}$

In formula, S is each conductor distance of shaft centers from, d _afor armouring mean diameter, A is armouring cross-sectional area, and δ is armouring equivalent thickness, $\mathrm{\δ}=\frac{A}{\mathrm{\π}{d}_A};K=\frac{1}{1+\frac{d_A}{\mathrm{\μ\δ}}};$

Eddy current loss factor:

${\mathrm{\λ}}_2^{\′\′}=\frac{2.25S^2{K}^2\mathrm{\δ}\×{10}^{-8}}{R\·d_A}$

Armor loss is magnetic hysteresis loss and eddy current loss sum, that is:

λ ₂＝λ′ ₂+λ″ ₂

Then armouring heat production rate is:

Q ₂＝λ ₂Q

Geometrical structure parameter adopts actual measured value, measurement parameter is substituted into above each formula, namely can be regarded as to obtain each several part heating part heat production rate, and at this, we flow through electric current for 400A for every phase conductor and calculate, then each several part heating part heat production rate is:

Every phase conductor: 59526W/m ³

Metal screen layer: 1631W/m ³

Armouring: 785W/m ³

So far, the calculating of heat production rate completes.

5) in ANSYS, load layers of material parameter, geometric model can be converted to finite element model by division unit, and as shown in Figure 2 b, loaded load also solves and obtains each node temperature of finite element model.Solving result is shown as cloud atlas, as shown in Figure 2 c, can understands the field distribution of triple cable internal temperature intuitively, also can extract cable each point temperature, the information such as heat flow density are used for research further.

In sum, the D modeling function of the present invention in conjunction with SolidWorks and the finite element analysis function of ANSYS, realize the Three-Dimensional Simulation of Temperature Fields of 10kV triple cable, operating process intuitive and convenient, model is accurately reliable, operation efficiency is high, and may extend to the finite element thermal analysis of the labyrinths such as cable intermediate joint, is worthy to be popularized.

The examples of implementation of the above are only the preferred embodiment of the present invention, not limit practical range of the present invention with this, therefore the change that all shapes according to the present invention, principle are done, all should be encompassed in protection scope of the present invention.

Claims (6)

1. a 10kV triple cable finite element thermal analysis method, is characterized in that, comprise the following steps:

1) geometry of 10kV triple cable, size, material parameter is determined;

2) SolidWorks is utilized to carry out three-dimensional modeling according to the geometry of 10kV triple cable;

3) three-dimensional model that SolidWorks sets up is imported ANSYS and the geometric model be converted in ANSYS;

4) according to electric current and the electric cable heating partial parameters of cable loading, heating part heat production rate is calculated;

5) in ANSYS, load layers of material parameter, division unit imposed load, solve and obtain 10kV triple cable thermo parameters method result.

2. a kind of 10kV triple cable finite element thermal analysis method according to claim 1, it is characterized in that: in step 1) in, mainly determine the interior external radius of the core of 10kV triple cable, interior semi-conductive layer, insulation course, outer semiconducting layer, copper shield, packed layer, inner sheath, armouring, each layer of oversheath, and need determine the temperature conductivity of layers of material and need to determine temperature conductivity, specific heat capacity, the density of layers of material for Transient calculation for stable state calculating.

3. a kind of 10kV triple cable finite element thermal analysis method according to claim 1, is characterized in that: in step 2) in, utilize SolidWorks software, carry out modeling according to 1/3rd of symmetric theory power taking cable radial direction in thermal conduction study, as follows:

2.1) to the modeling one by one of each Rotating fields of 10kV triple cable, wherein, core, inner semiconductor layer, insulation course, outer semiconductor layer, copper shield get radial half, and packed layer, inner sheath, armor, oversheath get radial 1/3rd modelings;

2.2) by step 2.1) in set up each layer model of obtaining and assemble in newly-built assembly, the 10kV triple cable three-dimensional model that radial direction gets 1/3rd can be obtained.

4. a kind of 10kV triple cable finite element thermal analysis method according to claim 1, it is characterized in that: in step 3) in, the triple cable three-dimensional model utilizing the data-interface of ANSYS to be set up by SolidWorks imports ANSYS and the geometric model be converted in ANSYS, as follows:

3.1) in SolidWorks, cable model assembly is exported as " x_t " formatted file;

3.2) in ANSYS, select Utility Menu>File>ImportGreatT.GreaT .GTPARA ..., select step 3.1) and middle " x_t " formatted file of deriving;

3.3) in ANSYS, select Utility Menu>PlotCtrls>StyleGreatT.G reaT.GTSolid Model Facets, select Normal Faceting in the choice box ejected after, hit OK is determined;

3.4) click right in ANSYS display interface, selects Replot;

3.5) in ANSYS, select Main Menu>Preprocessor>ModelingGr eatT.GreaT.GTOperate>Glue>Vo lum, each Rotating fields is successively selected to attempt bonding, until the success of model integrated bond, namely complete the foundation of ANSYS geometric model.

5. a kind of 10kV triple cable finite element thermal analysis method according to claim 1, is characterized in that, in step 4) in, comprise following calculating:

4.1) every phase proportion of goods damageds

The unit length direct current resistance of conductor under its maximum operating temperature:

R′＝R ₀×[1+α ₂₀(θ-20)]

In formula, R ₀the direct current resistance of conductor when being 20 DEG C, α ₂₀the temperature coefficient of material when being 20 DEG C, the maximum operating temperature that θ gets conductor is 90 DEG C;

The unit length AC resistance R=R ' (1+y of conductor under its maximum operating temperature _s+ y _p), wherein, kelvin effect factor:

$y_s=\frac{x_s^4}{192+{0.8x}_s^4}$

$x_s^2=\frac{8\mathrm{\πf}}{R^{\′}}\×{10}^{-7}{k}_s,$ K _sgetting empirical value is 1

Proximity effect factor:

$y_P=\frac{x_p^4}{192+{0.8x}_P^4}{\left(\frac{d_c}{s}\right)}^2\×[0.312{\left(\frac{d_c}{s}\right)}^2+\frac{1.18}{\frac{x_p^4}{192+{0.8x}_p^4}+0.27}]$

$x_p^2=\frac{8\mathrm{\πf}}{R^{\′}}\×{10}^{-7}{k}_p,$ K _pgetting empirical value is 0.8

In formula, d _cfor conductor diameter, s is the distance between each conductor axle center;

Every phase conductor heat production rate can be obtained by following formula:

$Q=\frac{I^2{R}_l}{V}=\frac{I^{2}R}{S}=\frac{I^2}{{\mathrm{\πr}}^2}$

In formula, r is cross-sectional area of conductor radius;

4.2) calculating of insulation course loss

The electric capacity of unit length cable:

$c=\frac{\mathrm{\ϵ}}{18\ln \left(\frac{D_i}{d_c}\right)}\×{10}^{-9}$

In formula, ε is insulating material dielectric coefficient, D _ifor insulation course diameter, d _cfor conductor diameter;

The insulation loss of every middle unit length cable is mutually obtained by following formula:

$W_d=\mathrm{\ω}\·c\·U_0^2\·\mathrm{tg\δ}$

In formula, U ₀for voltage-to-ground, tg δ is insulation loss factor under power-supply system and working temperature;

4.3) loss of metal screen layer and armouring is calculated

The loss factor of metal screen layer is:

${\mathrm{\λ}}_1=\frac{R_s}{R}\frac{1.5}{1+{(R_s/X)}^2}=\frac{R_s}{R}\frac{1.5}{1+{(R_s/2\mathrm{\ω}{10}^{-7}\ln \left(\frac{2s}{d}\right))}^2}$

In formula, R _sfor the resistance of cable unit length metallic sheath under maximum operating temperature, a _sfor the sectional area of metallic sheath; η is the ratio of metallic sheath temperature counter conductor temperature, gets 0.8;

After trying to achieve metal screen layer loss factor, then armouring heat production rate is:

Q ₁＝λ ₁Q

For armouring, hysteresis loss coefficient:

${\mathrm{\λ}}_2^{\′}=\frac{S^2{K}^2\×{10}^{-7}}{{\mathrm{Rd}}_A\mathrm{\δ}}$

In formula, S is each conductor distance of shaft centers from, d _afor armouring mean diameter, A is armouring cross-sectional area, and δ is armouring equivalent thickness, $\mathrm{\δ}=\frac{A}{{\mathrm{\πd}}_A};$ $K=\frac{1}{1+\frac{d_A}{\mathrm{\μ\δ}}};$

Eddy current loss factor:

${\mathrm{\λ}}_2^{\′\′}=\frac{2.25S^2{K}^2\mathrm{\δ}\×{10}^{-8}}{R\·d_A}$

Armor loss is magnetic hysteresis loss and eddy current loss sum, that is:

λ ₂＝λ′ ₂+λ″ ₂

Then armouring heat production rate is:

Q ₂＝λ ₂Q。

6. a kind of 10kV triple cable finite element thermal analysis method according to claim 1, it is characterized in that: in step 5) in, layers of material parameter is loaded in ANSYS, geometric model can be converted to finite element model by division unit, loaded load also solves and obtains each node temperature of finite element model, solving result is shown as cloud atlas and can understands the field distribution of triple cable internal temperature intuitively.