CN102830305B - Overheating fault simulating method for GIS (gas insulated switchgear) bus joint - Google Patents

Abstract

An overheating fault simulating method for GIS (gas insulated switchgear) bus joint includes steps of building a mathematical temperature-rising model according to a physical heating process of the GIS bus joint; performing similarity analysis according to the mathematical temperature-rising model, determining an accurate coupling field similarity relation; simplifying the mathematical temperature-rising model, determining an approximate coupling field similarity relation; determining a simulation test scheme of overheating faults of the GIS bus joint and a physical GIS bus joint similarity model under various contact conditions; implementing an overheating fault simulation test on the basis of the physical similarity model of the GIS bus joint according to the simulation test scheme, and acquiring simulation test data. By simulating the overheating faults of the GIS bus joint with the similarity model of the GIS bus joint, overheating fault mechanisms and reliability features are indirectly researched, the defects that protomodel simulation test is high in cost, equipment manufacturing period is long and reliability during test is poor are overcome, and implementing of temperature monitoring and routing inspection of the GIS bus joint are facilitated.

Description

GIS busbar joint Superheated steam drier analogy method

Technical field

The present invention relates to electrical equipment malfunction analogy method, particularly a kind of GIS busbar joint Superheated steam drier analogy method.

Background technology

Along with GIS (GAS Insulated Switchgear, gas-insulated switchgear) a large amount of coming into operation, because loose contact causes that GIS busbar joint is overheated and accident that is that cause happens occasionally, and become one of typical fault of GIS accident.Therefore, carrying out GIS busbar joint temperature monitoring runs significant with the safety and stablization of patrolling and examining for electric system.By Simulated GlS busbar joint Superheated steam drier, can the Superheated steam drier mechanism of survey and analysis GIS busbar joint and life characteristics, and then for GIS busbar joint temperature detection and patrol and examine important theory and implementation basis be provided.But, if utilize prototype GIS busbar joint to carry out fault simulation, not only experimentation cost is high, and there is the deficiencies such as device fabrication cycle length and experimentation poor reliability, can not simulate GIS busbar joint Superheated steam drier well, the monitoring be difficult to for GIS busbar joint temperature provides foundation with patrolling and examining.

Summary of the invention

For above-mentioned problems of the prior art, the object of the present invention is to provide a kind of GIS busbar joint Superheated steam drier analogy method, it can study Superheated steam drier mechanism and the reliability characteristic of GIS busbar joint equivalently, is conducive to GIS busbar joint temperature monitoring and carrying out of patrolling and examining.

For achieving the above object, the present invention by the following technical solutions:

A kind of GIS busbar joint Superheated steam drier analogy method, comprises step:

Physical process according to the heating of GIS busbar joint sets up temperature rise mathematical model;

Respectively similarity analysis is carried out to each physical process of GIS busbar joint superheating phenomenon according to described temperature rise mathematical model, the similarity criterion of each physical process is determined according to similarity analysis result, and according to the multi-scenarios method relation between the overheated each physical process of this similarity criterion, GIS busbar joint, determine the accurate similarity relation of coupled field;

In the accurate similarity relation of described coupled field and basis, above-mentioned temperature rise mathematical model is simplified, determine coupled field approximate similarity relation;

Determine the simulation test scheme of GIS busbar joint Superheated steam drier, according to GIS busbar joint contact information in described coupled field approximate similarity relation and actual motion, determine the GIS busbar joint physical scaled model under each contact conditions, carry out the Superheated steam drier simulation test based on this GIS busbar joint physical scaled model according to described simulation test scheme, obtain simulation test data.

According to the invention described above scheme, utilize GIS busbar joint scale model Simulated GlS busbar joint Superheated steam drier, indirectly study Superheated steam drier mechanism and reliability characteristic, overcome the deficiency of prototype simulation experimentation cost high, device fabrication cycle long and experimentation poor reliability, be conducive to GIS busbar joint temperature monitoring and carrying out of patrolling and examining.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of GIS busbar joint Superheated steam drier analogy method embodiment of the present invention.

Embodiment

Below in conjunction with better embodiment wherein, the present invention program is described in detail.

The schematic flow sheet of GIS busbar joint Superheated steam drier analogy method embodiment of the present invention has been shown in Fig. 1.

As shown in Figure 1, the GIS busbar joint Superheated steam drier analogy method in the present embodiment comprises step:

Step S101: the physical process according to the heating of GIS busbar joint sets up temperature rise mathematical model;

Step S102: respectively similarity analysis is carried out to each physical process of GIS busbar joint superheating phenomenon according to above-mentioned temperature rise mathematical model, the similarity criterion of each physical process is determined according to similarity analysis result, and according to the multi-scenarios method relation between the overheated each physical process of this similarity criterion, GIS busbar joint, determine the accurate similarity relation of coupled field;

Step S103: on the basis of the accurate similarity relation of above-mentioned coupled field, carries out suitable simplification to above-mentioned temperature rise mathematical model, determines coupled field approximate similarity relation;

Step S104: the simulation test scheme determining GIS busbar joint Superheated steam drier, according to GIS busbar joint contact information in above-mentioned coupled field approximate similarity relation and actual motion, determine the GIS busbar joint physical scaled model under each contact conditions, carry out the Superheated steam drier simulation test based on this GIS busbar joint physical scaled model according to above-mentioned simulation test scheme, obtain simulation test data.

According to the invention described above scheme, utilize GIS busbar joint scale model Simulated GlS busbar joint Superheated steam drier, indirectly study Superheated steam drier mechanism and reliability characteristic, overcome the deficiency of prototype simulation experimentation cost high, device fabrication cycle long and experimentation poor reliability, be conducive to GIS busbar joint temperature monitoring and carrying out of patrolling and examining.

The object obtaining simulation test data is for the ease of GIS busbar joint temperature monitoring and carrying out of patrolling and examining, and therefore, after above-mentioned steps S104, can also comprise step:

The life characteristics of step S105: according to above-mentioned simulation test data analysis GIS busbar joint Superheated steam drier mechanism, statistics GIS busbar joint, determines GIS busbar joint temperature monitoring and patrols and examines scheme.

Below in conjunction with the specific implementation process in concrete example wherein, each step in such scheme is described in detail.

Above-mentioned set up temperature rise mathematical model time, specifically can respectively from the physical process that electrical contact, eddy current loss, this three angle analysis GIS busbar joint superheating phenomenons that conduct heat comprise; And according to the relevant control equation in those physical process identified sign fields, vortex field, fluid field and temperature field and single-valued conditions, the relevant control equation obtained and single-valued conditions, be the temperature rise mathematical model of above-mentioned foundation.

Wherein, the physical process that GIS busbar joint superheating phenomenon comprises, generally has: the heat transfer of the Joule heat loss in the change of connection resistance, conductor, eddy current loss, conductor and shell on shell, conductor to the convection heat transfer' heat-transfer by convection of SF6 gas, shell to the convection heat transfer' heat-transfer by convection of air, conductor to the radiant heat transfer of shell and shell to the radiant heat transfer etc. of air.To the concrete analysis process of these physical processes, existing mode in prior art can be adopted to carry out, do not repeat them here.

When according to the relevant control equation in these physical process identified sign fields, vortex field, fluid field and temperature field and single-valued conditions, the relevant control equation obtained and single-valued conditions can be as described below.

Consider that GIS busbar joint cleaning inside degree is higher, thus can ignore the impact of film resistance, all conduction spots are equivalent to 1, then the Static Contact resistance that single contact is right is wherein, R _cfor contact resistance, ρ ₁, ρ ₂for the resistivity of contact to material, F is contact, and H is contact hardness.

Adopt A, φ-A method to set up the mathematical model analyzed vortex field, the field domain of Solving Three Dimensional Eddy Currents is divided into vortex cavity (outer wall) and non-vortex cavity (conductor).Maxwel's equaations in the expansion of vortex cavity and non-vortex cavity, respectively such as formula shown in (1), (2)

$J_s=\▿\×(\frac{1}{\mathrm{\μ}}\▿\×A)-\▿(\frac{1}{\mathrm{\μ}}\▿\·A)---\left(1\right)$

$\left\{\begin{array}{c}\▿\×(\frac{1}{\mathrm{\μ}}\▿\×A)-\▿(\frac{1}{\mathrm{\μ}}\▿\·A)+\mathrm{\σ}(\frac{\∂A}{\∂t}+\▿\mathrm{\φ})=0\\ \▿\·(-\mathrm{\σ}\frac{\∂A}{\∂t}-\mathrm{\σ}\▿\mathrm{\φ})=0\end{array}\right.---\left(2\right)$

In formula, A is vector magnetic potential, and μ is magnetic permeability, and σ is conductivity, J _sfor current density, t is current cycle.

Outer wall eddy current loss P _twith conductor Joule heat loss P _ccomputing formula be respectively

$P_t=\frac{1}{\mathrm{\σ}}{\∫}_v{(-\mathrm{\σ}\frac{\∂A}{\∂t}-\mathrm{\σ}\▿\mathrm{\φ})}^2\mathrm{dv}---\left(3\right)$

$P_c=\frac{1}{\mathrm{\σ}}{\∫}_c{J_s}^2\mathrm{dv}---\left(4\right)$

Conductor and outer wall transient heat conduction differential governing equation are

${\mathrm{\ρ}}_s{C}_s\frac{\∂T}{{\∂\mathrm{\τ}}_s}={\mathrm{\λ}}_s{\▿}^{2}T+{\mathrm{\Φ}}_v---\left(5\right)$

In formula, T is temperature, ρ _sfor the density of conductor/shell, C _sfor the specific heat capacity of conductor/shell, λ _sfor the coefficient of heat conductivity of conductor/shell, Ф _vfor heat generation rate, τ _sfor the time.

The differential governing equation group describing fluid (in wall SF6 and wall outer air) free convection heat transfer comprises the mass conservation, momentum conservation and energy conservation equation, respectively such as formula shown in (6), (7), (8), the border heat transfer differential equation of fluid is such as formula shown in (9).

$\frac{{\∂\mathrm{\ρ}}_f}{{\∂\mathrm{\τ}}_f}+{\mathrm{\ρ}}_f\▿\·V=0---\left(6\right)$

$\frac{\∂V}{{\∂\mathrm{\τ}}_f}+V\·\▿V=\frac{{\mathrm{\μ}}_f}{{\mathrm{\ρ}}_f}{\▿}^{2}V+\left(\frac{{\mathrm{\ρ}}_f-{\mathrm{\ρ}}_0}{{\mathrm{\ρ}}_f}\right)g---\left(7\right)$

${\mathrm{\ρ}}_f{C}_f(\frac{\∂T}{{\∂\mathrm{\τ}}_f}+V\·\▿T)={\mathrm{\λ}}_f{\▿}^{2}T---\left(8\right)$

$-{\mathrm{\λ}}_f{\left(\frac{\∂T}{\∂n}\right)}_w=h(T_w-T_f)---\left(9\right)$

In formula, V is flow velocity, and T is temperature, τ _sfor the time, ρ _ffor fluid density, C _pfor specific heat at constant pressure, λ _ffor flow thermal conductivity coefficient, μ _ffor fluid kinematic viscosity, g is acceleration of gravity, and n is boundary layer normal direction, and h is convective heat-transfer coefficient, T _w-T _ffor fluid temperature (F.T.) is poor.

By SF6 in wall and wall outer air stereoscopic be ideal gas, then have the Ideal-Gas Equation

PM＝ρRT (10)

In formula, P is gaseous tension, and M is gas molar quality, and R is gas constant.

Utilize the heat exchange amount of Newtonian Cooling formulae discovery convection heat transfer' heat-transfer by convection:

Q _c＝ShΔT (11)

Q in formula _cfor the quantity of heat convection, S is exchange hot side surface area, and Δ T is the mean temperature difference (MTD) of fluid and solid surface on heat-transfer surface.

To outer wall and outer wall, the radiant heat transfer to air is considered as two grey body surface-closed systems radiate heat transfers to conductor, calculates by formula (12)

$Q_r=\frac{A_1\mathrm{\σ}(T_1^4-T_2^4)}{\frac{1}{{\mathrm{\ϵ}}_1}+\frac{A_1}{A_2}(\frac{1}{{\mathrm{\ϵ}}_2}-1)}---\left(12\right)$

A in formula ₁, A ₂be respectively the surface area of grey surface 1,2, T ₁and T ₂be respectively the Kelvin temperature of two grey bodies, ε ₁and ε ₂be respectively the emissivity of two grey surfaces.

After establishing temperature rise mathematical model, similarity analysis can be carried out to each physical process of GIS busbar joint superheating phenomenon respectively according to above-mentioned temperature rise mathematical model, the similarity criterion of each physical process is determined according to similarity analysis result, and according to the multi-scenarios method relation between the overheated each physical process of this similarity criterion, GIS busbar joint, determine the accurate similarity relation of coupled field.

When carrying out similarity analysis to each physical process of GIS busbar joint superheating phenomenon respectively according to temperature rise mathematical model, respectively similarity analysis is carried out to each physical process that GIS busbar joint superheating phenomenon comprises, thus the similarity criterion of single physical process is determined in derivation, i.e. the similarity criterion of above-mentioned each physical process.When carrying out similarity analysis to the similarity criterion of each single physical process, determining the similarity criterion of each physical process, current existing equation analysis and dimensional method can be adopted to carry out, and concrete analysis mode does not repeat them here.

After the similarity criterion obtaining each single physical process, each physical process that the temperature rise of GIS busbar joint comprises can be considered on the basis of the similarity criterion of each single physical process, carry out multi-scenarios method similarity analysis, determine the accurate similarity relation of coupled field.

Wherein, multi-scenarios method similarity analysis refers to and carries out similarity analysis to conductor and outer wall, the followed thermal balance equation that conducts heat between outer wall and air, and wherein heat balance equation can be shown below:

$\left\{\begin{array}{c}{P}_c=Q_{r1}+Q_{c1}\\ P_t+P_c=Q_{r2}+Q_{c2}\end{array}---\left(13\right)\right.$

In formula, P _cfor the Joule heat loss of conductor, P _tfor the eddy current loss of tube wall, Q _r1, Q _r2represent conductor respectively to tube wall and tube wall to the radiant heat transfer amount of penetrating of air, Q _c1, Q _c2represent conductor respectively to SF6 and tube wall to the heat transfer free convection amount of air.

When carrying out multi-scenarios method similarity analysis, equation analysis and dimensional method can be adopted to carry out multi-scenarios method similarity analysis, obtain the accurate similarity relation of coupled field, the accurate similarity relation of this coupled field that derivation obtains, the required similarity relation met between the ratio of similitude being each eigenwert in stress field, electromagnetic field, temperature field and fluid field, concrete similarity analysis process can adopt equation analysis and dimensional method to carry out, and does not repeat them here.

After the accurate similarity relation of coupled field obtaining the temperature rise of GIS busbar joint, Accuracy Verification can also be carried out to this accurate similarity relation.

When verifying accurate similarity relation, the design defect that can first may exist in conjunction with GIS busbar joint in actual production or install bad situation, set up GIS busbar joint prototype geometric model, this prototype geometric model is by selecting suitable geometric similarity than setting up the similar geometry model corresponding with prototype, specifically three-dimensional graphics software can be passed through, such as Solidworks etc., draw GIS busbar joint prototype geometric model.Wherein, above-mentioned geometric similarity is than the physical dimension L that may be defined as prototype _pwith the physical dimension L of model _mratio K _l=L _p/ L _m.In theory, when above-mentioned governing equation and single-valued conditions all meet, this geometric similarity compares K _lcan choose arbitrarily, but in order to ensure similarity precision, geometric similarity compares K _lgenerally should not obtain excessive.In a specific implementation of the present invention program, the value K of this geometric similarity ratio _lcan 4. be set as

After setting up prototype geometric model, can according to the accurate ratio of similitude of each physical quantity, comprise: every physical parameter of gas, the outer gas of shell in conductor, shell, shell, source current effective value, source power frequency, temperature etc., apply corresponding physical condition, boundary condition and initial conditions respectively, calculate the power attenuation of prototype and similar geometry model, stable state and transient temperature rise, mainly comprise: when load current is constant, when GIS busbar joint contacts good, the steady temperature of contact, conductor and outer tube wall distributes and ramp-up time; When load current is constant, in GIS busbar joint loose contact situation, the steady temperature of contact, conductor and outer tube wall distributes and ramp-up time; When load current changes in time, the temperature changing regularity of contact, conductor and outer tube wall when GIS busbar joint contacts good; When load current changes in time, the temperature changing regularity of contact, conductor and outer tube wall when the loose contact of GIS busbar joint.Concrete computation process can be the ratio of similitude expression formula being obtained each physical quantity by similarity relation, by by the physical quantity of prototype and geometric similarity than the physical quantity of bringing physical quantity ratio of similitude expression formula into and can obtain scale model, existing Finite Element in prior art can be adopted to carry out the computation process of each physical quantity, not repeat them here.

Then, result of calculation and prototype are analyzed, verify the correctness of accurate similarity relation.When verifying, prototype and the power attenuation of similar geometry model, the result of calculation of temperature can be contrasted, whether the ratio of similitude of checking power attenuation, temperature meets, in theory, when getting rid of error effect, theoretic accurately similar precision should be 100%, if meet this precision conditions, then can judge that accurate similarity relation is correct.

Wherein, when being obtained the ratio of similitude expression formula of each physical quantity by similarity relation, concrete similarity relation can be as described below:

The process obtaining ratio of similitude expression formula according to above-mentioned similarity relation can adopt existing mode in prior art to carry out, and does not repeat them here.

Accurate similarity relation obtained above directly carries out similarity analysis to former governing equation and single-valued conditions to derive and the similarity relation that draws, in theory there is the highest precision, but, because accurate similarity relation is too harsh, in Practical Project, modeling is carried out very difficult according to accurate similarity relation, often be difficult to when simulation test meet, therefore, should on the basis of accurate similarity relation, actual demand according to concrete engineering carries out suitable simplification to above-mentioned temperature rise mathematical model, therefore, in the present invention program, also consider practicality and accuracy, after the correctness demonstrating accurate similarity relation, carry out further approximate similarity process.

Above-mentioned approximate similarity process, can be simplify above-mentioned temperature rise mathematical model according to the accurate similarity relation of above-mentioned coupled field, determine coupled field approximate similarity relation.The process of concrete approximate similarity process can be: on the basis of above-mentioned accurate similarity relation, in the scope that precision allows, by simplifying fluid field governing equation, determines coupled field approximate similarity relation.

When simplifying fluid field governing equation, determining coupled field approximate similarity relation, can be on the basis of accurate similarity relation, convection heat transfer' heat-transfer by convection in shell is equivalent to heat transfer, utilize test correlation substitution fluid field governing equation, thus the simplification realized accordingly temperature rise mathematical model, detailed process can be as described below.

First, the conductor in enclosed busbar and the convection heat transfer' heat-transfer by convection of SF6 belong to finite space free convection heat transfer.Be heat transfer by the free convection heat transfer Approximate Equivalent of the finite space, by introducing equivalent heat conductivity λ _e, calculate the quantity of heat convection Q _c1, specifically can be shown below:

λ _e＝0.4λ _f(Gr·Pr) ^0.2 (15)

$Q_{c1}=\frac{2\mathrm{\π}{\mathrm{\λ}}_e\mathrm{l\ΔT}}{\ln (D_{\mathrm{ti}}/D_{\mathrm{co}})}---\left(16\right)$

$\mathrm{Gr}=\frac{{\mathrm{g\α}}_V\mathrm{\Δ}{\mathrm{Tl}}^3{{\mathrm{\ρ}}_f}^2}{{{\mathrm{\μ}}_f}^2}---\left(17\right)$

$\mathrm{Pr}=\frac{{\mathrm{\μ}}_f{C}_P}{{\mathrm{\λ}}_f}---\left(18\right)$

λ in formula _efor equivalent heat conductivity, Gr and Pr is respectively grashof number and Prandtl number, Q _c1for the heat transfer free convection amount between conductor and outer wall, D _tiand D _cobe respectively outer wall inside radius and conductor external radius, Δ T is the temperature difference of conductor and outer wall, and l is conductor length.

Secondly, due to outer tube wall and wall outer air convection heat transfer' heat-transfer by convection because of the development of thermal boundary layer substantially interference-free, belong to large space natural convection, in engineering, extensively adopt Correlation farmula to calculate convective heat-transfer coefficient, therefore, the heat transfer free convection amount between following formula calculating outer wall and air can be utilized:

Nu＝0.11(Gr·Pr) ^1/3 (19)

$h=\frac{{\mathrm{\λ}}_f\mathrm{Nu}}{l}---\left(20\right)$

In formula, h is convective heat-transfer coefficient, and Nu is Nusselt number.

Equation according to the heat transfer free convection amount between above-mentioned conductor and outer wall, heat transfer free convection amount between outer wall and air carries out similarity analysis, thus draw above-mentioned coupled field approximate similarity relation, the method of concrete similarity analysis can adopt equation analysis and dimensional method to carry out, and will not add to repeat at this.

After obtaining coupled field approximate similarity relation, by modeling and numerical evaluation, the correctness of this coupled field approximate similarity relation can also be verified.

When carrying out the checking of approximate similarity relation, concrete proof procedure can be similar with the above-mentioned process verified accurate similarity relation, it can be the approximate similarity ratio according to each physical quantity, comprise source current effective value, source power frequency, temperature conductor, shell, gas in shell, every physical parameter of the outer gas of shell etc., apply corresponding physical condition respectively, boundary condition and initial conditions, calculate the power attenuation of prototype and scale model, stable state and transient temperature rise, mainly comprise: when load current is constant, contact when GIS busbar joint contacts good, the steady temperature distribution of conductor and outer tube wall and ramp-up time, when load current is constant, when the loose contact of GIS busbar joint, the steady temperature of contact, conductor and outer tube wall distributes and ramp-up time, when load current changes in time, the temperature changing regularity of contact, conductor and outer tube wall when GIS busbar joint contacts good, when load current changes in time, the temperature changing regularity of contact, conductor and outer tube wall when the loose contact of GIS busbar joint.Concrete computation process can be the ratio of similitude expression formula being obtained each physical quantity by similarity relation, by by the physical quantity of prototype and geometric similarity than the physical quantity of bringing physical quantity ratio of similitude expression formula into and can obtain scale model, existing Finite Element in prior art can be adopted to carry out the computation process of each physical quantity, not repeat them here.

Then, result of calculation and prototype are analyzed, the correctness of checking approximate similarity relation.When verifying, can contrast prototype and the power attenuation of similar geometry model, the result of calculation of temperature, whether the ratio of similitude of checking power attenuation, temperature meets, in theory, when getting rid of error effect, theoretic accurately similar precision should be 100%, if meet this precision conditions, then can judge that approximate similarity relation is correct.

Wherein, when being obtained the ratio of similitude expression formula of each physical quantity by similarity relation, concrete similarity relation can be as described below:

$\left\{\begin{array}{c}{K}_F={K_l}^2\\ K_{R_c}={K_l}^{-1}\\ K_A=K_I={K_l}^{1.5}\\ K_{\mathrm{\φ}}=K_B={K_l}^{0.5}\\ K_t={K_l}^2\\ K_{P_c}=K_{P_c}=K_{Q_{r1}}=K_{Q_{r2}}={K_l}^2\\ K_{Q_{c2}}=K_{Q_{c1}}={K_l}^2\\ K_H=K_{{\mathrm{\ρ}}_1}=K_{{\mathrm{\ρ}}_2}=1\\ K_{\mathrm{\μ}}=K_{\mathrm{\σ}}=K_{{\mathrm{\λ}}_s}=K_{C_s}=K_{{\mathrm{\ρ}}_s}=1\\ K_{{\mathrm{\ϵ}}_1}=K_{{\mathrm{\ϵ}}_2}=K_{{\mathrm{\ϵ}}_3}=1\\ K_{{\mathrm{\λ}}_f}=K_{{\mathrm{\μ}}_f}=K_{C_P}=K_{{\mathrm{\ρ}}_{\mathrm{AIR}}}=1\\ K_{{\mathrm{\ρ}}_{{\mathrm{SF}}_6}}=K_l\\ K_h=K_l\\ K_T=1\end{array}\right.$

The process obtaining ratio of similitude expression formula according to above-mentioned similarity relation can adopt existing mode in prior art to carry out, and does not repeat them here.

According to GIS busbar joint contact situation in above-mentioned coupled field approximate similarity relation and actual motion, determine the GIS busbar joint physical scaled model under each contact conditions, and carry out the Superheated steam drier simulation test based on this GIS busbar joint physical scaled model according to determined above-mentioned simulation test scheme, obtain simulation test data.

Before carrying out GIS busbar joint Superheated steam drier simulation test, need reasonably to plan simulation test, first need to set the distribution of life-span of GIS busbar joint and accelerated life model.In the present invention program, suppose that the life-span of GIS busbar joint is distributed as Weibull distribution, accelerated life model is Arrhenius relationship.

When determining simulation test scheme, can be specifically under the prerequisite of satisfied expection zero failure probability, according to the life-span of the Weibull distribution of above-mentioned GIS busbar joint distribute, the accelerated life model of Arrhenius relationship, calculate the stress level and corresponding sample dispense number that make approximate square error minimum, thus determine candidate test programme, here concrete computation process can adopt existing mode in prior art to carry out, and does not repeat them here.

After obtaining candidate test programme, optimum test programme can be obtained by Monte Carlo simulation analysis, the mode being obtained optimum test programme by Monte Carlo simulation analysis from candidate test scheme is identical with mode existing in prior art, does not repeat them here.

After obtaining optimum test programme (i.e. above-mentioned simulation test scheme), physical scaled model under the different contact conditions of the many covers of processing, build experiment porch, and carry out simulation test according to optimum test programme obtained above, Simulated GlS busbar joint is from heating to overheated overall process of burning, and carry out omnidistance temperature monitoring, record test temperature data.

Then, the test temperature data obtained are processed, can be specifically analyze GIS busbar joint from heating until temperature changing regularity the overall process of burning, sum up the mechanism of GIS busbar joint Superheated steam drier, concrete analysis, the process of summary can adopt any possible mode to carry out, and concrete analysis, the mode of summary do not repeat them here.

Then, the correctness of aforementioned hypothesis is verified by model-Montfort method of inspection and the test of hypothesis of bartlett's test method, utilize the parameter that Best Linear Unbiased Estimate and inverse moment method are estimated in Weibull distribution and accelerate equation, calculate the reliability characteristic under normal stress level, comprise fiduciary level, crash rate, mean lifetime and Q-percentile life, for GIS busbar joint temperature monitoring and the enforcement of patrolling and examining provide theoretical foundation and technical support, determine GIS busbar joint temperature monitoring accordingly and patrol and examine scheme.

The above embodiment only have expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.

Claims (7)

1. a GIS busbar joint Superheated steam drier analogy method, is characterized in that, comprise step:

Physical process according to the heating of GIS busbar joint sets up temperature rise mathematical model;

Respectively similarity analysis is carried out to each physical process of GIS busbar joint superheating phenomenon according to described temperature rise mathematical model, the similarity criterion of each physical process is determined according to similarity analysis result, and according to the multi-scenarios method relation between the overheated each physical process of this similarity criterion, GIS busbar joint, determine the accurate similarity relation of coupled field;

On the basis of the accurate similarity relation of described coupled field, described temperature rise mathematical model is simplified, determine coupled field approximate similarity relation;

Determine the simulation test scheme of GIS busbar joint Superheated steam drier, according to GIS busbar joint contact information in described coupled field approximate similarity relation and actual motion, determine the GIS busbar joint physical scaled model under each contact conditions, carry out the Superheated steam drier simulation test based on this GIS busbar joint physical scaled model according to described simulation test scheme, obtain simulation test data;

According to the accurate similarity relation of described coupled field, the step that described temperature rise mathematical model simplifies is comprised:

Conductor in enclosed busbar and the convection heat transfer' heat-transfer by convection of SF6 belong to finite space free convection heat transfer, be heat transfer, pass through the free convection heat transfer Approximate Equivalent of the finite space heat transfer free convection amount Q between calculating conductor and outer wall _c1, wherein, λ _e=0.4 λ _f(GrPr) ^0.2, λ _efor equivalent heat conductivity, l is conductor length, and Δ T is the temperature difference of conductor and outer wall, D _tiand D _cobe respectively outer wall inside radius and conductor external radius, λ _ffor flow thermal conductivity coefficient, Gr and Pr is respectively grashof number and Prandtl number;

Pass through calculate the heat transfer free convection amount h between outer wall and air, wherein, Nu=0.11 (GrPr) ^1/3, λ _ffor flow thermal conductivity coefficient, l is conductor length, and Nu is Nusselt number, Gr and Pr is respectively grashof number and Prandtl number;

According to the heat transfer free convection amount Q between described conductor and outer wall _c1, heat transfer free convection amount h between outer wall and air equation carry out similarity analysis, draw coupled field approximate similarity relation.

2. GIS busbar joint Superheated steam drier analogy method according to claim 1, is characterized in that, after the described simulation test data of acquisition, also comprises step:

According to described simulation test data analysis GIS busbar joint Superheated steam drier mechanism, the life characteristics of statistics GIS busbar joint, determines GIS busbar joint temperature monitoring and patrols and examines scheme.

3. GIS busbar joint Superheated steam drier analogy method according to claim 1 and 2, it is characterized in that, the described process setting up temperature rise mathematical model comprises:

Respectively from the physical process that the angle analysis GIS busbar joint superheating phenomenon of electrical contact, eddy current loss, heat transfer comprises;

According to relevant control equation and the single-valued conditions in described physical process identified sign field, vortex field, fluid field and temperature field.

4. GIS busbar joint Superheated steam drier analogy method according to claim 1 and 2, is characterized in that, after deriving the accurate similarity relation of coupled field, also comprise step:

By modeling and numerical evaluation, verify the correctness of the accurate similarity relation of described coupled field.

5. GIS busbar joint Superheated steam drier analogy method according to claim 1 and 2, is characterized in that, after obtaining described coupled field approximate similarity relation, also comprises step:

By modeling and numerical evaluation, verify the correctness of described coupled field approximate similarity relation.

6. GIS busbar joint Superheated steam drier analogy method according to claim 1 and 2, is characterized in that:

The accurate similarity relation of described coupled field is drawn by carrying out similarity analysis derivation to thermal balance equation;

Described coupled field approximate similarity relation is drawn by carrying out similarity analysis derivation to thermal balance equation.

7. GIS busbar joint Superheated steam drier analogy method according to claim 1 and 2, it is characterized in that, the life-span of setting GIS busbar joint is distributed as Weibull distribution, accelerated life model is Arrhenius relationship, under the prerequisite of satisfied expection zero failure probability, calculate the stress level and corresponding sample dispense number that make approximate square error minimum, obtain described simulation test scheme in conjunction with Monte Carlo simulation analysis.