CN104899379B - Cross-linked polyethylene insulated cable temperature field finite element method based on ANSYS - Google Patents
Cross-linked polyethylene insulated cable temperature field finite element method based on ANSYS Download PDFInfo
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- CN104899379B CN104899379B CN201510314013.0A CN201510314013A CN104899379B CN 104899379 B CN104899379 B CN 104899379B CN 201510314013 A CN201510314013 A CN 201510314013A CN 104899379 B CN104899379 B CN 104899379B
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- 239000004020 conductor Substances 0.000 claims abstract description 15
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- 238000012546 transfer Methods 0.000 claims description 15
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- 239000004576 sand Substances 0.000 claims description 11
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- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a kind of cross-linked polyethylene insulated cable temperature field finite element methods based on ANSYS, include the following steps successively：First, using cross-linked polyethylene insulated cable as research object, parametrization Geometric Modeling is carried out based on simulation software ANSYS；Secondly, current excitation is applied to cross-linked polyethylene insulated cable and carries out magnetic field analysis：Again, voltage drive is applied to cross-linked polyethylene insulated cable and carries out analysis of electric field；Joule thermal losses, eddy-current loss and the dielectric loss that magnetic field analysis and analysis of electric field are obtained are loaded into simultaneously on cross-linked polyethylene insulated cable carries out temperature field analysis as heat source, carries out the calculating in cross-linked polyethylene insulated cable temperature field.The present invention has great flexibility and adaptability to the solution of complex region and border issue, the temperature field of cross-linked polyethylene insulated cable conductor can more accurately be calculated, and then excavate the potential of current-carrying capacity of cable ability, the investment of cable can not only be saved, moreover it is possible to improve the utilization rate and operation level of cable.
Description
Technical field
The present invention relates to power cable technical field more particularly to a kind of cross-linked polyethylene insulated cables based on ANSYS
Temperature field finite element method.
Background technology
With extensive use of the power cable in electric line, power cable and its ambient temperature are accurately determined
The distribution of field and the current-carrying capacity of cable have weight for improving the utilization rate of power cable and the dynamic Load adjustment of power cable
The meaning wanted.
Nonlinear load proportion in industry and the electrical load of commercial power system is increasing, nonlinear load
It is distorted the sinusoidal waveform of electric current and voltage in power grid, so as to generate a large amount of harmonic waves.Utilities Electric Co. for improve power because
It counting largely using capacitor group, electronic power convertor is widely used for the reliability and efficiency of raising system in industrial quarters, this
A little equipment cause to generate the enlarge-effect of voltage waveform and current waveform distortion with the interaction of PFC capacitor group.
Equally, harmonic wave can all be generated in the production of electric power, transmission, conversion and the links that use.It can make after harmonic injection power grid
Reactive power increases, and power factor reduces, it could even be possible to causing parallel resonance or series resonance, damaging electrical equipment and doing
Disturb the normal work of communication line.
Flowing of the harmonic current in power grid can generate additional active power loss on the line, so as to reduce power transmission line
The current-carrying capacity on road.General harmonic current proportion compared with fundamental current is little, but harmonic frequency is high, the collection skin effect of conducting wire
It answers, kindred effect makes harmonic wave resistance ratio fundamental wave resistance big, therefore extension wire resistance loss is non-negligible caused by harmonic wave.For
Using the transmission system of power cable, due to dielectric, there are distribution capacity, can also generate additional insulation dielectric loss.Its
Middle insulation dielectric loss is decided by isolation material, thickness and voltage.Cable with shielded layer is as high-frequency harmonic is deposited
Generating power frequency electromagnetic field around it, the metal screen layer inside cable will generate eddy-current loss.These are all to cause cable
And its ambient temperature raising, the major reason so as to limit its current-carrying capacity.
Before the eighties, the method for generally use mirror image calculates the temperature field of buried cable.With numerical heat transfer
Development, most in the latest 20 years, using numerical computation method to underground cable temperature field carry out simulation be calculated it is more and more
Application.It is in the majority with finite difference calculus, FInite Element, Finite Volume Method for Air, boundary element method in numerical computation method.Calculation medium
It is lost, the method for eddy-current loss has analytic method and numerical computation method.Analytic method, which compares better simply situation, to meet essence
Accelerate calculating speed on the basis of degree, but for more complicated Cable Group, while calculate Kelvin effect, kindred effect, whirlpool
During stream loss, there are equation group is excessively huge and solve the shortcomings that difficult for analytic method.It common are limit calculus of finite differences and boundary element method
Numerical computation methods is waited also to have deficiency, are specifically suitable for the feelings of laying area simple shape with finite differential analysis
Condition, to more complicated region, then error is larger.And when using Boundary Element Analysis, when there is multi-cable to be laid with problem for processing
Or during an actual cable ditch problem with multi-layer Soil, the boundary of boundary element method is too complicated too much, and calculation amount is very big.Mesh
Before, cross-linked polyethylene insulated cable is had been widely used in the transmission line of electricity and distribution of each voltage class of electric system, and
Occupy great share.Therefore, suitable method is selected, which to carry out simulation calculating to cross-linked polyethylene insulated cable temperature field, to be had
Larger application value.
Invention content
The object of the present invention is to provide a kind of cross-linked polyethylene insulated cable temperature field FEM calculation sides based on ANSYS
Method carries out simulation calculating to cross-linked polyethylene insulated cable temperature field, and it is excellent to have that easy to operate, calculating speed is fast, precision is high etc.
Point can more accurately calculate the temperature field of cross-linked polyethylene insulated cable conductor, and then excavate the potential of current-carrying capacity of cable ability,
The investment of cable can not only be saved, moreover it is possible to improve the utilization rate and operation level of cable.
The technical solution adopted by the present invention is：
Cross-linked polyethylene insulated cable temperature field finite element method based on ANSYS, includes the following steps successively：
A：Using cross-linked polyethylene insulated cable as research object, parametrization Geometric Modeling is carried out based on simulation software ANSYS,
Model include wire stylet, conductor shield, insulating layer, insulation screen, metal screen layer, filled layer, inner sheath, armor and
Oversheath；
B：Current excitation is applied to cross-linked polyethylene insulated cable, magnetic field analysis is carried out to cross-linked polyethylene insulated cable,
The vortex of joule thermal losses, the eddy-current loss that metal screen layer generates and armor generation generated by unit export wire stylet is damaged
Consumption；
C：Voltage drive is applied to cross-linked polyethylene insulated cable, analysis of electric field is carried out to cross-linked polyethylene insulated cable,
The dielectric loss generated by unit export by insulating layer；
D：What the joule thermal losses that wire stylet in step B and step C is generated, metal screen layer and armor generated respectively
The dielectric loss that eddy-current loss and insulating layer generate, which is loaded into simultaneously on cross-linked polyethylene insulated cable, is used as crosslinked polyethylene
The heat source of insulated cable carries out temperature field analysis, carries out the calculating in cross-linked polyethylene insulated cable temperature field.
Step A includes the following steps：
A1：The upper and lower sides of selective cross-linking polyethylene insulated cable are spread with layer of sand, are protection boards close to layer of sand outside, are protected up and down
Backplate spacing is not less than 300mm, protection board width be more than cable both sides not less than 200mm, on soil coboundary distance protection plate
Boundary is not less than 0.8m, and lower boundary takes the soil for being not less than 2m apart from lower protection board, and right boundary takes closest crosslinking respectively
Polyethylene insulated cable surface clear distance side is not less than the soil of 2m, and the directly buried installation region and crosslinked polyethylene in bounds are exhausted
Edge cable body forms the overall region of cross-linked polyethylene insulated cable directly buried installation together；
A2：By cross-linked polyethylene insulated cable part with two orthogonal diameters circle be divided into four parts, then
Circumference and radial line segments are segmented respectively, then carry out subdivision using the method for mapping subdivision, cross-linked polyethylene insulated cable
Three-phase subdivision method is identical, and filled layer, inner sheath, armor and oversheath are by controlling the free subdivision of line segment length, cable week
The part enclosed passes through control unit size and the free subdivision of line segment segments.
The step D includes the following steps：
D1：The model simplification that step A is built is two dimensional model, takes lowest level soil as known to object boundary temperature the
First-type boundary condition takes right boundary soil to take ground for second kind boundary condition known to normal direction heat flow density on object boundary
Face soil is the air themperature that is in contact with soil and convection transfer rate is known third boundary condition；
D2 resets electric field unit, selects thermal field unit, and to unit material attribute again assignment, will be divided in B by magnetic field
As analysis of electric field part, the medium as derived from unit damages in analysis part joule thermal losses, eddy-current loss and C as derived from unit
Consumption is imported into models for temperature field as the heat source of cross-linked polyethylene insulated cable simultaneously；
D3 carries out the calculating in cross-linked polyethylene insulated cable temperature field, respectively obtains cross-linked polyethylene insulated cable direct-burried
Lay overall region, cross-linked polyethylene insulated cable ontology and cross-linked polyethylene insulated cable insulating layer Temperature Distribution cloud atlas.
The lowest level soil moisture is 25 DEG C.
The normal direction heat flow density of the right boundary soil is 0.
The surface soil takes natural convection air Transfer Boundary Condition.
The present invention is to carry out mould to cross-linked polyethylene insulated cable temperature field using FInite Element based on simulation software ANSYS
Intend calculating, FInite Element has the grid and node of arbitrary arrangement, has great spirit to the solution of complex region and border issue
Activity and adaptability can more accurately calculate the temperature field of cross-linked polyethylene insulated cable conductor, and then excavate current-carrying capacity of cable
The potential of ability can not only save the investment of cable, moreover it is possible to improve the utilization rate and operation level of cable.The present invention has operation
Simply, the advantages that speed is fast, and accuracy is high.
The present invention is based on FInite Elements, are mapped cross-linked polyethylene insulated cable inner layers using ANSYS softwares
Subdivision, institute's subdivision cell configuration rule are more accurate to the temperature computation inside cable.
The present invention is suitable for harmonic wave under a variety of system of laying such as soil directly buried installation, cable duct laying, cable installation in pipe to multiple
The Study on Temperature Field of miscellaneous Cable Group.
Description of the drawings
Fig. 1 is the flow chart of the present invention；
Fig. 2 is the structure diagram of cross-linked polyethylene insulated cable model；
Fig. 3 is cross-linked polyethylene insulated cable ontology subdivision graph；
Fig. 4 is cross-linked polyethylene insulated cable body part A phase subdivision graphs；
Fig. 5 is cross-linked polyethylene insulated cable directly buried installation overall region Temperature Distribution cloud atlas enlarged drawing；
Fig. 6 is cross-linked polyethylene insulated cable body temperature cloud charts；
Fig. 7 is cross-linked polyethylene insulated cable insulating layer Temperature Distribution cloud atlas；
Fig. 8 is dielectric loss with frequency variation curve figure；
Fig. 9 is eddy-current loss with metal screen layer relative permeability change curve；
Figure 10 is dielectric loss with dielectric dissipation factor change curve；
Figure 11 is joule thermal losses and eddy-current loss with size of current change curve.
Specific embodiment
As shown in Figure 1, the present invention is based on the cross-linked polyethylene insulated cable temperature field finite element method of ANSYS, according to
It is secondary to include the following steps：
A, using the cross-linked polyethylene insulated cable of 10kV models YJLV22-10-3*300 as research object, based on emulation
Software ANSYS carries out parametrization Geometric Modeling, model include wire stylet 1, conductor shield 2, insulating layer 3, insulation screen 4,
Metal screen layer 5, filled layer 6, inner sheath 7, armor 8 and oversheath 9, the crosslinked polyetylene insulated electricity of YJLV22-10-3*300
The technical parameter of cable is as shown in Table 1；Cross-linked polyethylene insulated cable model structure schematic diagram is as shown in Fig. 2, modeling specifically includes
Following steps：
A1：According to national standard GB50217-94 Code for design of cables of electric works and DL/T 5221-2005 urban electric power cables
Circuit designing technique provides, considers situation when cross-linked polyethylene insulated cable soil directly buried installation, selective cross-linking polyethylene
The upper and lower sides of insulated cable are spread with layer of sand, are protection boards close to layer of sand outside, protect plate spacing up and down not less than 300mm, protection
Plate width is more than that cable both sides are not less than 200mm, and soil coboundary distance protection plate coboundary is not less than 0.8m, with reference to related text
It offers and understands：Temperature only change near cable it is more violent, when far from cable when, the soil moisture will be identical with environment temperature.It is logical
Often the soil apart from cable 2m is not influenced by cable.Therefore lower boundary takes the soil for being not less than 2m apart from lower protection board, left
Right margin takes the soil that closest cross-linked polyethylene insulated cable surface clear distance side is not less than 2m respectively, straight in bounds
It buries laying area and cross-linked polyethylene insulated cable ontology forms the whole area of cross-linked polyethylene insulated cable directly buried installation together
Domain.During directly buried installation ambient enviroment interrelated geometrical parameters as shown in Table 2, directly buried installation when ambient enviroment relevant physical parameter such as
Shown in table three.
The upper and lower sides of selective cross-linking polyethylene insulated cable are spread with layer of sand in the embodiment of the present invention, are to protect close to layer of sand outside
Backplate, up and down protect plate spacing be 300mm, protection board width be more than cable both sides be 200mm, soil coboundary distance protection plate
Coboundary is 0.8m, according to pertinent literature：Temperature only change near cable it is more violent, when far from cable when, soil
Temperature will be identical with environment temperature.Soil usually apart from cable 2m is not influenced by cable.Therefore lower boundary is taken under distance
The soil of protection board 2m, right boundary take the soil of closest cross-linked polyethylene insulated cable surface clear distance side 2m respectively, use
To establish model.
A2：By cross-linked polyethylene insulated cable part with two orthogonal diameters circle be divided into four parts, then
Circumference and radial line segments are segmented respectively, then carry out subdivision using the method for mapping subdivision, cross-linked polyethylene insulated cable
Three-phase subdivision method is identical, and filled layer 6, inner sheath 7, armor 8 and oversheath 9 are by controlling the free subdivision of line segment length, electricity
Part around cable passes through control unit size and the free subdivision of line segment segments.
Be divided into four parts justifying with two orthogonal diameters per phase cable section, circumference and diameter line segment respectively into
Row segmentation, each circumference, which is equally divided into 4 sections, 4 sections, is all divided into 20 segments for every section, and the diameter line segment where wire stylet 1 is divided into 20 sections
And it is 0.6 to control space options, the diameter line segment where conductor shield 2 is equally divided into 5 sections, and the diameter line segment where insulating layer 3 is put down
10 sections are divided into, the diameter line segment where insulation screen 4 is equally divided into 5 sections, and the diameter line segment where metal screen layer 5 is divided into 10 sections
And it is 0.3 to control space options, division unit type selection quadrangle, then carries out subdivision, crosslinking using the method for mapping subdivision
The subdivision of A phases, B phases and C phases is just the same in polyethylene insulated cable.Peripheral big circumference where filled layer 6 is equally divided into 4
Section, every section is equally divided into 20 segments and controls space options as free, then division unit type selection triangle uses certainly
By subdivision.Inner sheath 7, armor 8 and 9 place circumference of oversheath are equally divided into 4 sections, and every section is equally divided into 10 segments, draw
Subdivision type selects triangle, then carries out free subdivision.Part (layer of sand, protection board, soil) around cable passes through control
Cell size processed and line segment segments use free subdivision.20034 units are always obtained in entire model.It is crosslinked polyetylene insulated
Cable is followed successively by A phases, B phases, C phases from upper, lower-left, bottom right number.Wherein, subdivision is 3600 quadrangle lists to A phases cable in total
Member, element number are followed successively by 1-3600；Subdivision is 3600 quadrilateral units to B phases cable in total, and element number is followed successively by 3601-
7200；Subdivision is 3600 quadrilateral units to C phases cable in total, and element number is followed successively by 7201-10800.Armor 8 cuts open in total
Divide 80 triangular elements, element number is followed successively by 12033-12112.Cross-linked polyethylene insulated cable ontology subdivision graph such as Fig. 3
Shown, cross-linked polyethylene insulated cable body part A phase subdivision graphs are as shown in Figure 4.
One YJLV22-10-3*300 twisted polyethylene cable technical parameters of table
Ambient enviroment interrelated geometrical parameters during two directly buried installation of table
Ambient enviroment relevant physical parameter during three directly buried installation of table
B, applies current excitation to cross-linked polyethylene insulated cable, and magnetic field analysis is carried out to cross-linked polyethylene insulated cable,
The whirlpool of joule thermal losses, the eddy-current loss that metal screen layer 5 generates and the generation of armor 8 generated by unit export wire stylet 1
Stream loss；
It is to be noted that there are Kelvin effect in the case of harmonic wave, vortex is had in cross-linked polyethylene insulated cable, still
It is twisted into the core of engineering cable in practice by many stock thin wires, in order to practical with simulation software closer to engineering
Wire stylet 1 of the cross-linked polyethylene insulated cable per phase is handled directly as a conductor during ANSYS is modeled, wire stylet
Electric current in 1 is substantially equally distributed, therefore does not consider the vortex effect of core in the analysis of cross-linked polyethylene insulated cable
Should, it is loaded directly into current density and is emulated.53 magnetic field units of PLANE are selected, to 5 part of metal screen layer and armor 8
When dividing material properties assignment, the Keyoption options of setting Unit 53 are 1, i.e., degree of freedom is VOLT and AZ；Other parts (packet
Including air) the Keyoption options of setting Unit 53 is 0, that is, degree of freedom is AZ.Loading section firstly the need of coupling A respectively
The voltage of phase, the voltage of B phases and C phases metal screen layer 5 and armor 8；Then magnetic flux boundary condition is loaded, i.e., in outermost layer
AZ=0 is controlled on the boundary of soil；Finally loading encourages, and is in the conductor part injection amplitude of A phases, B phases and C phases respectively
500A, phase differ 120 ° of balanced three-phase current successively, and electric current is loaded by current density.It is 500HZ items in frequency
Under part, the vortex that the joule thermal losses of calculating wire stylet 1 generation and metal screen layer 5 and armor 8 generate respectively respectively is damaged
Consumption, it is 97.0703J, and export joule thermal losses and whirlpool successively by unit that can calculate by the loss that magnetic field part generates in total
Stream loss is stored in document.Joule thermal losses and eddy-current loss are exported successively as shown in Table 4 by unit.Joule heat in table four
Loss and eddy-current loss are referred to as loss of field.ELEM, JH1, VOL and EDDYPOWE are respectively element number, the unit of cells
The loss of field that loss of field, the volume of the unit and unit that volume generates generate.JH1 units are J/m3, VOL units are
m3, EDDYPOWE units are J.JH1 is multiplied by VOL and obtains EDDYPOWE during table four is often gone.
Table four joule thermal losses and eddy-current loss as derived from unit
C, applies voltage drive to cross-linked polyethylene insulated cable, and analysis of electric field is carried out to cross-linked polyethylene insulated cable,
The dielectric loss generated by unit export by insulating layer 3；
Magnetic field units are reset first and delete the node coupled on metal screen layer 5 and armor 8 on the node that couples,
121 electric field units of PLANE are selected, to unit material attribute again assignment；Then the conductor current potential of A phases, B phases and C phases is distinguished
It couples and applies the symmetrical triphasic potentials of 10kV (above earth potential virtual value is 8574V), the current potential of metal screen layer 5 is also distinguished into coupling
Merge the current potential of loading 0V, under the conditions of frequency is 500HZ, it is 5.59922J to calculate by the dielectric loss that insulating layer 3 generates；Most
It exports the heat of dielectric loss generation successively by unit afterwards and is saved in document.By unit successively derived dielectric loss such as table
Shown in five.In table five ELEM, JH2, VOL and DPOWER be respectively element number, the unit of cells volume generate dielectric loss,
The dielectric loss that the volume of the unit and the unit generate.JH2 units are J/m3, VOL units are m3, DPOWER units are J.Table
Five often go in JH2 be multiplied by VOL and obtain DPOWER.
The dielectric loss as derived from unit of table five
D, by the joule thermal losses that wire stylet 1 generates in step B and step C, metal screen layer 5 and armor 8 produce respectively
The dielectric loss that raw eddy-current loss and insulating layer 3 generate is loaded on cross-linked polyethylene insulated cable poly- as crosslinking simultaneously
The heat source of ethylene insulated cable carries out temperature field analysis, carries out the calculating in cross-linked polyethylene insulated cable temperature field.
Heat transfer includes in calorifics theory：Heat transfer, convection current and radiation.Heat transfer is non-uniform temperature on object or has temperature
The phenomenon that thermal energy moves when poor, is the main heat transfer phenomenon in solid.Convection current is that have temperature between body surface and the fluid being in contact
The phenomenon of Heat occurred when poor.Different according to the direction of the temperature difference, thermal energy can pass to fluid by the surface of solids, and vice versa.Stream
The flowing of body can be because fluid temperature (F.T.) is uneven cause density contrast due to the free convection that generates or by equipment such as fans
Caused by forced convection or above two factor concur, be known as convection current coexists.Object is passed with electromagnetic wave
The mode of energy is sent to be known as radiating.
Simulation software ANSYS carry out temperature field analysis calculating basic principle be first handled object is divided into it is limited
A unit (including several nodes), then solves each section under certain boundary conditions and primary condition according to conservation of energy principle
Equation of heat balance at point, thus calculates each node temperature, further solves other correlatives.In simulation software ANSYS
Mainly there is two major class of steady-state thermal analysis and Transient Thermal Analysis with calorifics theory analysis.The present invention is based on heat transfer and thermal convection current two
Kind heat transfer type is with the joule thermal losses of the steady-state thermal analysis research generation of wire stylet 1, the dielectric loss of the generation of insulating layer 3, gold
Belong to the eddy-current loss that shielded layer 5 and armor 8 generate respectively and fever influence is risen on power transmission cable temperature.
Steady-state thermal analysis refers to the temperature of system not time to time change.Specifically, the heat for as flowing into system adds
The heat that upper system itself generates is equal to the heat of outflow system, then system is in hot stable state.It is arbitrarily saved in steady-state thermal analysis
The temperature of point does not change over time.In rectangular coordinate system, the expression formula of two-dimensional steady-state heat conduction equation is：
In formula, k is the thermal conductivity factor of material, and unit is W/ (m DEG C)；S is endogenous pyrogen；X and y represents two-dimensional coordinate system
Two reference axis, T are the temperature of arbitrary node.
In order to enable the equation of heat balance group established has unique solution, additional certain boundary condition, boundary condition are needed
Mainly include following three classes：
First Boundary Condition refers to the temperature on object boundary it is known that as shown in formula (2)：
T|Γ=Tw (2)
In formula, Г is object boundary, TwFor known temperature value, T represents temperature, T |ΓTemperature for object boundary.
Second kind boundary condition refers to the normal direction heat flow density on object boundary it is known that as shown in formula (3)：
In formula, k is the thermal conductivity factor of material, and unit is W/ (m DEG C)；Q is known heat flow density value, and unit is W/ ㎡；T
Represent temperature；N represents the normal orientation of soil right boundary.
Third boundary condition refers to the temperature T for the fluid media (medium) being in contact with objectfIt is with convection transfer rate α
Know, as shown in formula (4)：
In formula, α is convection transfer rate, and unit is W/ (㎡ DEG C)；K is the thermal conductivity factor of material, and unit is W/ (m
℃)；N represents the normal orientation of soil coboundary.
Step D specifically includes following steps：
D1：Since the length of cross-linked polyethylene insulated cable can consider endless, length direction compared with its radius
Temperature hardly changes, therefore the model simplification that step A is built is two dimensional model.By the expression formula of two-dimensional steady-state heat conduction equation
(1) it is found that steady temperature is only related with the thermal conductivity factor of material.It is the first kind known to object boundary temperature to take lowest level soil
Boundary condition, the lowest level soil moisture are 25 DEG C；Take right boundary soil for normal direction heat flow density on object boundary
The second kind boundary condition known, the normal direction heat flow density of the right boundary soil is 0；Surface soil is taken to connect with soil
Tactile air themperature and convection transfer rate is known third boundary condition, and the surface soil takes natural convection air
Transfer Boundary Condition；
D2：Electric field unit is reset, selects thermal field unit, and to unit material attribute again assignment.It will be divided in B by magnetic field
As analysis of electric field part, the medium as derived from unit damages in analysis part joule thermal losses, eddy-current loss and C as derived from unit
Consumption is imported into models for temperature field as the heat source of cross-linked polyethylene insulated cable simultaneously；Total loss and preservation are exported by unit
Into document, total loss is exported as shown in Table 6 by unit.Joule thermal losses and eddy-current loss are referred to as magnetic field damage in table six
Consumption.ELEM, JH1, VOL, EDDYPOWE, JH2 and DPOWER be respectively element number, the unit of cells volume generate magnetic field damage
What loss of field, the dielectric loss of unit of cells volume generation and unit that consumption, the unit volume, the unit generate generated
Dielectric loss.JH1, JH2 unit are J/m3, VOL units are m3, EDDYPOWE, DPOWER unit are J.JH1 multiplies during table six is often gone
EDDYPOWE is obtained with VOL, JH2 is multiplied by VOL and obtains DPOWER.
The loss total as derived from unit of table six
77 thermal field units of PLANE are selected after electric field unit is reset, to unit material attribute again assignment.By in B by magnetic
As electric part, the dielectric loss as derived from unit is same in field part eddy-current loss and joule thermal losses and C as derived from unit
When imported into temperature field analysis as the heat source of cross-linked polyethylene insulated cable.Wire stylet 1, conductor shield 2, insulating layer 3,
The corresponding unit in this nine parts of insulation screen 4, metal screen layer 5, filled layer 6, inner sheath 7, armor 8 and oversheath 9
Number is respectively 1-12112.
D3：The calculating in cross-linked polyethylene insulated cable temperature field is carried out, respectively obtains cross-linked polyethylene insulated cable direct-burried
Lay the Temperature Distribution cloud atlas of overall region, cross-linked polyethylene insulated cable ontology and cross-linked polyethylene insulated cable insulating layer 3.
Cross-linked polyethylene insulated cable directly buried installation overall region Temperature Distribution cloud atlas is as shown in figure 5, cross-linked polyethylene insulated cable sheet
Temperature cloud charts are as shown in fig. 6, the Temperature Distribution cloud atlas of cross-linked polyethylene insulated cable insulating layer 3 is as shown in Figure 7.
As shown in Fig. 5,6 and 7, layer of sand around cross-linked polyethylene insulated cable ontology and cross-linked polyethylene insulated cable,
Protection board, the soil moisture closer from cable body are higher, B phase cable temperature highests, and temperature reaches 92.4372 DEG C, A phases and
C phase cables take second place.The temperature of A phases, B phases and C phase cable conductors core 1 is sufficiently close to.Three wire stylets 1 are each phase cable cross-sections
Highest temperature area.From the point of view of cross-linked polyethylene insulated cable body interior, 3 portion temperature of insulating layer variation ladder in each layer structure
Degree is maximum, coincide with actual conditions.Because the thermal conductivity factor of wire stylet 1 and metal screen layer 5 is far longer than the other portions of cable
Point, so the thermal resistance of wire stylet 1 and metal screen layer 5 is smaller, temperature rate of change is also smaller.Although conductor shield 2, insulation
Shielded layer 4 is identical and smaller with the thermal conductivity factor of insulating layer 3, but the thickness of insulating layer 3 be far longer than conductor shield 2 and absolutely
The thickness of edge shielded layer 4, therefore, 3 thermal resistance of insulating layer are far longer than the thermal resistance of conductor shield 2 and the thermal resistance of insulation screen 4,
3 temperature rate of change of insulating layer is maximum.Part (such as layer of sand, protection board and soil) except cross-linked polyethylene insulated cable ontology
Temperature change in non-uniform Distribution, it is smaller from the more remote temperature rate of change of cable.
As shown in Fig. 8,9,10 and 11, electric current, frequency, the relative permeability of metal screen layer 5, dielectric dissipation factor are considered
Variation to Joule heat loss, the influence of eddy-current loss and dielectric loss.Fig. 9,10 and 11 use control variate method, every time only
Change one because usually studying the influence to another factor.Frequency, the relative permeability of metal screen layer 5, dielectric loss
Factor, wire stylet 1 size of current influence whether the Wen Sheng of threephase cable.Specifically, 1 electric current of wire stylet increase can cause
The joule thermal losses increase that wire stylet 1 generates, while can also cause cross-linked polyethylene insulated cable metal screen layer 5 and armor
The 8 eddy-current loss increases generated respectively, while the influence to Joule heat loss is far longer than the influence to eddy-current loss, therefore right
The temperature of cross-linked polyethylene insulated cable, which rises, generates large effect.The relative permeability increase of metal screen layer 5 can damage vortex
Consumption produces bigger effect, and eddy-current loss also increases therewith.The dielectric dissipation factor increase of insulating layer 3 can cause dielectric loss to increase
Greatly.When frequency increases, dielectric loss and eddy-current loss increase, and the influence to eddy-current loss is far longer than the shadow to dielectric loss
It rings, therefore, the influence brought by Harmonious Waves in Power Systems is non-negligible, and especially higher hamonic wave is to cross-linked polyethylene insulated cable temperature
Situation about rising.
Claims (5)
1. the cross-linked polyethylene insulated cable temperature field finite element method based on ANSYS, which is characterized in that successively include with
Lower step：
A：Using cross-linked polyethylene insulated cable as research object, parametrization Geometric Modeling, model are carried out based on simulation software ANSYS
Including wire stylet, conductor shield, insulating layer, insulation screen, metal screen layer, filled layer, inner sheath, armor and outer shield
Set；
B：Current excitation is applied to cross-linked polyethylene insulated cable, magnetic field analysis is carried out to cross-linked polyethylene insulated cable, by list
The eddy-current loss of joule thermal losses, the eddy-current loss that metal screen layer generates and armor generation that member export wire stylet generates；
C：Voltage drive is applied to cross-linked polyethylene insulated cable, analysis of electric field is carried out to cross-linked polyethylene insulated cable, by list
The dielectric loss that member export is generated by insulating layer；
D：The joule thermal losses that wire stylet in step B and step C is generated, the vortex that metal screen layer and armor generate respectively
The dielectric loss that loss and insulating layer generate is loaded on cross-linked polyethylene insulated cable simultaneously as crosslinked polyetylene insulated
The heat source of cable carries out temperature field analysis, carries out the calculating in cross-linked polyethylene insulated cable temperature field；Step D includes following step
Suddenly：
D1：The model simplification that step A is built is two dimensional model, and it is the first kind known to object boundary temperature to take lowest level soil
Boundary condition takes right boundary soil to take ground native for second kind boundary condition known to normal direction heat flow density on object boundary
Earth is the temperature for the air being in contact with soil and convection transfer rate is known third boundary condition；
D2 resets electric field unit, selects thermal field unit, and to unit material attribute again assignment, by B by magnetic field analysis portion
As analysis of electric field part, the dielectric loss as derived from unit is same in point joule thermal losses, eddy-current loss and C as derived from unit
When imported into models for temperature field as the heat source of cross-linked polyethylene insulated cable；
Total loss is exported by unit and is saved in document, and total loss includes joule thermal losses, eddy-current loss and medium
Loss, joule thermal losses and eddy-current loss are referred to as loss of field, should if the loss of field that unit of cells volume generates is JH1
Unit volume is VOL, and the loss of field which generates is EDDYPOWE, and the dielectric loss which generates is
JH2, the dielectric loss which generates is respectively DPOWER, and the loss of field JH1 that each unit of cells volume generates is multiplied by this
Unit volume VOL obtains the loss of field EDDYPOWE of unit generation, the dielectric loss that each unit of cells volume generates
JH2 is multiplied by unit volume VOL and obtains the dielectric loss DPOWER of unit generation；
D3 carries out the calculating in cross-linked polyethylene insulated cable temperature field, respectively obtains cross-linked polyethylene insulated cable directly buried installation
Overall region, cross-linked polyethylene insulated cable ontology and cross-linked polyethylene insulated cable insulating layer Temperature Distribution cloud atlas.
2. the cross-linked polyethylene insulated cable temperature field finite element method according to claim 1 based on ANSYS,
It is characterized in that, step A includes the following steps：
A1：The upper and lower sides of selective cross-linking polyethylene insulated cable are spread with layer of sand, are protection boards close to layer of sand outside, upper and lower protection board
Spacing is not less than 300mm, and protection board width is more than cable both sides not less than 200mm, soil coboundary distance protection plate coboundary
Not less than 0.8m, lower boundary takes the soil for being not less than 2m apart from lower protection board, and right boundary takes the closest poly- second of crosslinking respectively
Alkene insulated cable surface clear distance side is not less than the soil of 2m, directly buried installation region and crosslinked polyetylene insulated electricity in bounds
Cable ontology forms the overall region of cross-linked polyethylene insulated cable directly buried installation together；
A2：Circle is divided into four parts by cross-linked polyethylene insulated cable part with two orthogonal diameters, then circumference
It is segmented respectively with radial line segments, then subdivision, the three-phase of cross-linked polyethylene insulated cable is carried out using the method for mapping subdivision
Subdivision method is identical, and filled layer, inner sheath, armor and oversheath are by controlling the free subdivision of line segment length, around cable
Part passes through control unit size and the free subdivision of line segment segments.
3. the cross-linked polyethylene insulated cable temperature field finite element method according to claim 1 based on ANSYS,
It is characterized in that：The lowest level soil moisture is 25 DEG C.
4. the cross-linked polyethylene insulated cable temperature field finite element method according to claim 1 based on ANSYS,
It is characterized in that：The normal direction heat flow density of the right boundary soil is 0.
5. the cross-linked polyethylene insulated cable temperature field finite element method according to claim 1 based on ANSYS,
It is characterized in that：The surface soil takes natural convection air Transfer Boundary Condition.
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