CN109100046A - A kind of cast bare conductor heating temperature acquisition methods - Google Patents
A kind of cast bare conductor heating temperature acquisition methods Download PDFInfo
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- CN109100046A CN109100046A CN201810812811.XA CN201810812811A CN109100046A CN 109100046 A CN109100046 A CN 109100046A CN 201810812811 A CN201810812811 A CN 201810812811A CN 109100046 A CN109100046 A CN 109100046A
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- bare conductor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
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Abstract
The present invention relates to a kind of cast bare conductor heating temperature acquisition methods, and this method comprises the following steps: (1) obtaining cast bare conductor resistance；(2) size of current and cast bare conductor resistance passed through according to cast bare conductor obtains total Joule heat of cast bare conductor fever；(3) temperature rise of cast bare conductor adstante febre is obtained according to total Joule heat of cast bare conductor fever；(4) temperature of cast bare conductor adstante febre is obtained according to the temperature rise of environment temperature and cast bare conductor adstante febre.Compared with prior art, the method for the present invention is easy, as a result accurately and reliably.
Description
Technical field
The present invention relates to technical field of high voltage, more particularly, to a kind of cast bare conductor heating temperature acquisition methods.
Background technique
Tube type bus is the key equipment in power system transformer substation, for the safety of maintenance transmission system and power equipment
Operation has a very important significance.Important component of the copper pipe bare conductor as pipe typed insulation bus-bars conductor part, hair
Hot temperature has important research significance for entire tube type bus conductor.
In recent years, the application with tube type bus in the power system, some problems are also displayed, for example cast is female
The accidents such as fire even occur for the excessively high insulation ag(e)ing that will lead to of line heating temperature, can cause centainly to the safe and stable operation of power grid
It influences.It analyzes from the heating cause of tube type bus, due to tube type bus conductor part, i.e. copper pipe, can be produced when passing through high current
Raw a large amount of heat, and these heats are exactly the main reason for causing pipe mother to generate heat.Therefore it is used as heat source, to copper in tube type bus
Fever research on pipe just has important practical value.
Currently, the fever of cast bare conductor can be obtained by theoretical formula or simulation software numerical calculations, based on having
The software emulation numerical value for limiting first method calculates, and dependent on computer hardware facility and consummate software operation, is poorly suitable for designing
The quick and easy calculating demand in unit scene, and when passing through theoretical formula method conductor temp.-elevating temperature, traditional research object limit
In power cable or Conventional insulation conductor, and calculating process is more complicated.
Summary of the invention
It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and provide a kind of cast bare conductors to send out
Hot method for acquiring temperature.
The purpose of the present invention can be achieved through the following technical solutions:
A kind of cast bare conductor heating temperature acquisition methods, this method comprises the following steps:
(1) cast bare conductor resistance is obtained；
(2) size of current and cast bare conductor resistance passed through according to cast bare conductor obtains the fever of cast bare conductor
Total Joule heat；
(3) temperature rise of cast bare conductor adstante febre is obtained according to total Joule heat of cast bare conductor fever；
(4) temperature of cast bare conductor adstante febre is obtained according to the temperature rise of environment temperature and cast bare conductor adstante febre.
Step (1) cast bare conductor resistance is obtained by following formula:
Wherein, R is cast bare conductor resistance, and ρ is cast bare conductor resistivity, and L is cast bare conductor length, r1For cast
Bare conductor outer radius, r2For cast bare conductor inside radius.
Total Joule heat of step (2) cast bare conductor fever is obtained by following formula: Q=I2R, wherein Q is cast bare conductor
Total Joule heat of fever, I are the size of current that cast bare conductor passes through, and R is cast bare conductor resistance.
The temperature rise of step (3) cast bare conductor adstante febre is obtained by following formula:
Wherein, Δ T is the temperature rise of cast bare conductor adstante febre, and Q is total Joule heat of cast bare conductor fever, and h is convection current
The coefficient of heat transfer, SIt dissipatesFor cast bare conductor heat dissipation area.
Cast bare conductor heat dissipation area SIt dissipatesIt obtains in the following way: SIt dissipates=2 π r1L, wherein L is cast bare conductor
Length, r1For cast bare conductor outer radius.
The temperature of step (6) cast bare conductor adstante febre obtains in the following way: T=T0+ Δ T, wherein T is cast
The temperature of bare conductor adstante febre, T0For environment temperature, Δ T is the temperature rise of cast bare conductor adstante febre.
Compared with prior art, the present invention has the advantage that
(1) for the method for the present invention independent of simulation software and computer hardware facility, implementation process is simple and convenient, and has
Feasibility；
(2) the cast bare conductor heating temperature result that the method for the present invention obtains is accurate and reliable, compared to numerical result
Error is no more than 0.04%, suitable for engineer application.
Detailed description of the invention
Fig. 1 is the flow diagram of cast bare conductor heating temperature acquisition methods of the present invention.
Specific embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.Note that the following embodiments and the accompanying drawings is said
Bright is substantial illustration, and the present invention is not intended to be applicable in it object or its purposes is defined, and the present invention does not limit
In the following embodiments and the accompanying drawings.
Embodiment
The analysis of tube type bus heating principle:
It is analyzed according to the model of tube type bus, taking the tube type bus of unit length is object.To bus leading body
P is lost in speechMIn the state of reaching thermal balance, heat can be passed from copper pipe to dielectric by way of heat transfer
It passs, is denoted as QMF；Surrounding medium can also be passed in a manner of free convection, be denoted as QMD, it is flat that this three parts energy meets the first heat
Weigh equation:
In formula, vmFor bus temperature, vkFor skin temperature, DMFor bus outer diameter, DKFor envelope outer diameter, CKFor the thickness of shell
Degree, λ is thermal coefficient, and δ is insulation thickness, FlFor unit length of conductor heat dissipation area.
For the tube type bus shell of the application research, calorific value is the heat P of conductor conduction itselfM.This two
The environment for dividing energy all to pass to surrounding in a manner of free convection and radiation under thermal equilibrium state, is denoted as Q respectivelyKFWith
QKD.Therefore it can be concluded that the second heat balance equation:
Wherein, v0For environment temperature, aKDFor the convection transfer rate of shell and extraneous air, when bus service condition,
Sectional dimension, when the conditions such as surface state determine, above formula items are vm, vkThe non-thread shape function of (bus, skin temperature), because
The two equation groups are constituted a Groebner Basis by this, can therefrom solve vm, vk.If with vm, xu, vk, xuTable respectively
The permission temperature for showing bus-bars conductor and shell, then working as vm<vm, xu, vk<vk, xuWhen, identified bus bar sizes are just able to satisfy scattered
Heat request.
Since the structure of tube type bus is in addition to there are also insulation systems etc. for copper pipe, the above are entire pipe typed insulation buses
On heat transfer theory analysis.Using above heat analysis as reference, next using the copper pipe in pipe mother as object, heat point is carried out
Analysis.
(1) calorific value
The calorific value of copper pipe includes the heat of conductor resistance loss and the heat of solar radiation.
A, the heat Q of conductor resistance lossR
The conductor of unit length passes through bus current IWWhen, by the heat of resistance loss generation are as follows:
The AC resistance R of conductoracAre as follows:
Wherein, RdcFor the D.C. resistance of conductor, KfFor the skin effect coefficient of conductor, ρ is conductor temperature when being 20 DEG C
Dc resistivity, αtTemperature-coefficient of electrical resistance when being 20 DEG C, θwFor the running temperature of conductor, S is conductor cross sectional area.
B, the heat Q of solar radiationt
The energy for absorbing solar radiation will cause conductor temperature raising, and the conductor of all installations without is considered as the shadow of sunshine
It rings.For unit length circularity conductor, QtIt can calculate are as follows:
Qt=EtAtFt=EtAtD,
Wherein, EtFor solar radiation power density, China takes Et=1000W/m2, AtIt is conductor to shining upon heat
Absorptivity generally takes 0.23-0.46 for new line, takes 0.4, F heretArea is shined upon for unit length of conductor, D is to lead
The overall diameter of body, numerically equal to Ft。
(2) heat dissipation capacity
The heat dissipation capacity of conductor includes heat loss through convection amount, heat loss through radiation amount and heat conduction and heat radiation amount.
A, heat loss through convection amount Ql
By thermal conduction study it is found that the heat that is transmitted of heat loss through convection is directly proportional to the temperature difference and heat dissipation area, i.e., conductor is to wandering
Heat are as follows:
Ql=αl(θw-θ0)Fl,
In formula, αlFor heat loss through convection coefficient, according to formula αl=1.5 (θw-θ0)0.35Show that natural convection air coefficient is
5.898 θw、θ0Respectively conductor running temperature and ambient air temperature, FlFor unit length of conductor heat dissipation area.
B, heat loss through radiation amount Qf
In formula, ε is the relative radiation coefficient of conductor material, takes 0.6.
For the heat dissipation on copper pipe, predominantly heat loss through convection, therefore heat conduction and heat radiation amount is no longer described in detail.
According to heat balance principle, when the calorific value on copper pipe reaches balance with heat dissipation capacity, the temperature on copper pipe will no longer
Variation, keep stablize, at this time the temperature on copper pipe be it is through-flow on copper pipe after heating temperature.Based on above-mentioned, cast bare conductor
Main exothermic heat source is the heat of conductor resistance loss, and solar radiation calorific value is much smaller than resistive heat losses, therefore ignores
Solar radiation fever.For the heat dissipation of cast bare conductor, predominantly heat loss through convection.
Therefore, as shown in Figure 1, a kind of cast bare conductor heating temperature acquisition methods, this method comprises the following steps:
(1) cast bare conductor resistance is obtained；
(2) size of current and cast bare conductor resistance passed through according to cast bare conductor obtains the fever of cast bare conductor
Total Joule heat；
(3) temperature rise of cast bare conductor adstante febre is obtained according to total Joule heat of cast bare conductor fever；
(4) temperature of cast bare conductor adstante febre is obtained according to the temperature rise of environment temperature and cast bare conductor adstante febre.
Step (1) cast bare conductor resistance is obtained by following formula:
Wherein, R is cast bare conductor resistance, and ρ is cast bare conductor resistivity, and L is cast bare conductor length, r1For cast
Bare conductor outer radius, r2For cast bare conductor inside radius.
Total Joule heat of step (2) cast bare conductor fever is obtained by following formula: Q=I2R, wherein Q is cast bare conductor
Total Joule heat of fever, I are the size of current that cast bare conductor passes through, and R is cast bare conductor resistance.For cast bare conductor,
The Joule heat q of unit volume fever are as follows:
The temperature rise of step (3) cast bare conductor adstante febre is obtained by following formula:
Wherein, Δ T is the temperature rise of cast bare conductor adstante febre, and Q is total Joule heat of cast bare conductor fever, and h is convection current
The coefficient of heat transfer, SIt dissipatesFor cast bare conductor heat dissipation area.Cast bare conductor heat dissipation area SIt dissipatesIt obtains in the following way: SIt dissipates=2 π
r1L, wherein L is cast bare conductor length, r1For cast bare conductor outer radius.
The temperature of step (6) cast bare conductor adstante febre obtains in the following way: T=T0+ Δ T, wherein T is cast
The temperature of bare conductor adstante febre, T0For environment temperature, Δ T is the temperature rise of cast bare conductor adstante febre.
In the present embodiment, it is known that the specification of cast bare conductor is: outer diameter 80mm, wall thickness 12.5mm, length are
500mm, material are copper, and environment temperature is 40 DEG C.The various parameters value of material copper is as shown in table 1.
The various parameters value of 1 bronze medal of table
| Parameter | Copper thermal coefficient | Copper resistance rate | Electric current | Convection transfer rate |
| Numerical value | 377W/m·℃ | 1.75×10-8Ω·m | 4000A | 6.6W/(m2·K) |
Known cast bare conductor resistivity is ρ, and cast bare conductor length is L, cast bare conductor outer radius r1=40mm, root
Cast bare conductor inside radius r is obtained according to bare conductor wall thickness2=27.5mm, the electric current that cast bare conductor passes through are I, and h changes for convection current
Hot coefficient, SIt dissipatesFor cast bare conductor heat dissipation area, environment temperature T0.Wherein heat dissipation area SIt dissipatesFor outermost surface product, take
Value can pass through formula=2 π × r1× L is acquired.
Therefore, cast bare conductor resistance:
The Joule heat of cast bare conductor unit volume fever:
Total Joule heat of cast bare conductor fever:
Q=I2R=52.8W,
The temperature rise of cast bare conductor adstante febre:
The temperature of cast bare conductor adstante febre:
T=T0T=40+63.66=103.66 DEG C of+Δ.
At 40 DEG C of environment temperature, when by 4000A electric current, the temperature of cast bare conductor adstante febre is carried out limited
First method numerical simulation, by simulation result it is found that the maximum temperature to generate heat on cast bare conductor is 103.69 DEG C, minimum temperature is
103.68 DEG C, mean temperature is 103.685 DEG C, and temperature rise is 63.685 DEG C.
According to above the method for the present invention and FInite Element numerical simulation as a result, the two calculated result is made following comparison,
It is shown in Table 2 in detail.According to the Comparative result in table 2 it is found that the result and actual emulation result that are obtained using the method for the present invention are basic
Unanimously, to demonstrate the real effectiveness of the method for the present invention.
Temperature comparisons under 2 two methods of table
| Method | FInite Element numerical simulation (40 DEG C) | This method | Error |
| Temperature rise (DEG C) | 63.685 | 63.66 | 0.04% |
| Maximum temperature | 103.69 | 103.66 | 0.03% |
The method of the present invention is independent of simulation software and computer hardware facility, and process is simple and convenient, and the method for the present invention obtains
The result and FInite Element Numerical Simulation Results error obtained is no more than 0.04%, is suitable for engineer application.
Above embodiment is only to enumerate, and does not indicate limiting the scope of the invention.These embodiments can also be with other
Various modes are implemented, and can make in the range of not departing from technical thought of the invention it is various omit, displacement, change.
Claims (6)
1. a kind of cast bare conductor heating temperature acquisition methods, which is characterized in that this method comprises the following steps:
(1) cast bare conductor resistance is obtained；
(2) size of current and cast bare conductor resistance passed through according to cast bare conductor obtains total coke of cast bare conductor fever
It has burning ears；
(3) temperature rise of cast bare conductor adstante febre is obtained according to total Joule heat of cast bare conductor fever；
(4) temperature of cast bare conductor adstante febre is obtained according to the temperature rise of environment temperature and cast bare conductor adstante febre.
2. a kind of cast bare conductor heating temperature acquisition methods according to claim 1, which is characterized in that step (1) pipe
Type bare conductor resistance is obtained by following formula:
Wherein, R is cast bare conductor resistance, and ρ is cast bare conductor resistivity, and L is cast bare conductor length, r1It is led for cast is naked
External radius, r2For cast bare conductor inside radius.
3. a kind of cast bare conductor heating temperature acquisition methods according to claim 1, which is characterized in that step (2) pipe
Total Joule heat of type bare conductor fever is obtained by following formula: Q=I2R, wherein Q is total Joule heat of cast bare conductor fever, I
For the size of current that cast bare conductor passes through, R is cast bare conductor resistance.
4. a kind of cast bare conductor heating temperature acquisition methods according to claim 1, which is characterized in that step (3) pipe
The temperature rise of type bare conductor adstante febre is obtained by following formula:
Wherein, Δ T is the temperature rise of cast bare conductor adstante febre, and Q is total Joule heat of cast bare conductor fever, and h is heat convection
Coefficient, SIt dissipatesFor cast bare conductor heat dissipation area.
5. a kind of cast bare conductor heating temperature acquisition methods according to claim 4, which is characterized in that cast bare conductor
Heat dissipation area SIt dissipatesIt obtains in the following way: SIt dissipates=2 π r1L, wherein L is cast bare conductor length, r1For cast bare conductor
Outer radius.
6. a kind of cast bare conductor heating temperature acquisition methods according to claim 1, which is characterized in that step (6) pipe
The temperature of type bare conductor adstante febre obtains in the following way: T=T0+ Δ T, wherein T is the temperature of cast bare conductor adstante febre
Degree, T0For environment temperature, Δ T is the temperature rise of cast bare conductor adstante febre.
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| CN201810812811.XA CN109100046A (en) | 2018-07-23 | 2018-07-23 | A kind of cast bare conductor heating temperature acquisition methods |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112484883A (en) * | 2020-12-01 | 2021-03-12 | 大连理工江苏研究院有限公司 | System and method for evaluating thermal state of contact net and bare conductor of substation |
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| CN102297732A (en) * | 2011-07-01 | 2011-12-28 | 徐州工程学院 | Measuring method for temperature of electrohydraulic control coil of automobile |
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2018
- 2018-07-23 CN CN201810812811.XA patent/CN109100046A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101979973A (en) * | 2010-09-15 | 2011-02-23 | 青海电力科学试验研究院 | Radiating capacity testing and accounting method for over 110kV transformer at high altitude |
| CN102297732A (en) * | 2011-07-01 | 2011-12-28 | 徐州工程学院 | Measuring method for temperature of electrohydraulic control coil of automobile |
Non-Patent Citations (1)
| Title |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112484883A (en) * | 2020-12-01 | 2021-03-12 | 大连理工江苏研究院有限公司 | System and method for evaluating thermal state of contact net and bare conductor of substation |
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