CN112924332A - SO in GIS equipment based on CFD technology2Diffusion characteristic determination method - Google Patents

SO in GIS equipment based on CFD technology2Diffusion characteristic determination method Download PDF

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CN112924332A
CN112924332A CN202110110103.3A CN202110110103A CN112924332A CN 112924332 A CN112924332 A CN 112924332A CN 202110110103 A CN202110110103 A CN 202110110103A CN 112924332 A CN112924332 A CN 112924332A
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concentration
diffusion
gas
absolute pressure
time
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CN112924332B (en
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张英
贺毅
张靖
王为
王明伟
余鹏程
赵世钦
潘云
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Guizhou Power Grid Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract

The invention discloses a CFD technology-based SO in GIS equipment2A diffusion characteristic determining method, comprising: for SF6Carrying out equal-proportion modeling on the electrical equipment model; determination of initial concentration vs. SO2The effect of diffusion; determination of absolute pressure vs SO2The effect of diffusion; determining each monitoring point SO of the model2The concentration change condition; obtaining that the larger the initial concentration is, the longer the time for the diffusion to reach uniformity is under the condition of the same pressure and different initial concentrations; the greater the absolute pressure SO2The greater the diffusion rate of (A), SO2The less time is required for diffusion to homogeneity; the technical problems that in the prior art, no one researches the diffusion characteristic of the characteristic decomposition product SO2 in GIS equipment, and reference cannot be provided for further judging equipment faults and the like are solved.

Description

SO in GIS equipment based on CFD technology2Diffusion characteristic determination method
Technical Field
The invention belongs to the technical field of gas diffusion characteristic research, and particularly relates to a CFD (computational fluid dynamics) -technology-based SO (sulfur dioxide) in GIS (gas insulated switchgear)2A diffusion characteristic determination method.
Background
Sulfur hexafluoride (SF)6) Because of their extremely stable chemical properties, excellent insulating properties and arc extinguishing properties, gases are widely used in electrical equipment such as Gas Insulated Switchgear (GIS) and high-voltage circuit breakers of 35kv and above. Pure SF at normal temperature and pressure6The gas has good stability, and SF is used when internal faults such as discharge occur6The gas is decomposed at high temperature due to failure, and is mixed with SF6Small amount of oxygen, water and solid insulating medium mixed in the electric equipment react further to produce SO2And H2S and the like. Wherein, SO2As SF6The gas production rate of the gas insulated electric equipment with the most marked fault characteristic decomposer continuously increases along with the development of the fault, the higher the content of the gas insulated electric equipment, the more serious the internal fault of the characteristic equipment, and the clear SO in the standard2Is the most typical characteristic decomposition gas, and has great significance in judging equipment faults and monitoring characteristic decomposition products SO2The method has a plurality of means, including an electrochemical sensor method, an ultraviolet spectrum method, a photoacoustic spectrometry method and the like, and is applied to the field of on-site monitoring of the transformer substation. The research on SO is precisely because the technology for monitoring characteristic decomposition products and judging equipment faults tends to mature, and the accuracy of monitoring the fault decomposition products is related to the gas diffusion effect2The diffusion effect in the GIS equipment has very important significance.
However, no one has studied the characteristic decomposition product SO in the prior art2The diffusion characteristic in the GIS device can not provide reference for further judging the device fault.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: providing a CFD technology-based SO in GIS equipment2A method for determining diffusion characteristics, which aims to solve the problem that no one has studied the characteristic decomposition product SO in the prior art2In GIS equipmentThe medium diffusion characteristic can not provide reference for further judging equipment failure, and the like.
The technical scheme of the invention is as follows:
SO in GIS equipment based on CFD technology2A diffusion characteristic determining method, comprising:
step 1, to SF6The electrical equipment model is modeled in equal proportion, the model is divided into two parts, a lower cylinder is an equipment body, an upper cylinder is an air intake port, and the whole geometric model is of a closed structure;
step 2, determining initial concentration to SO2The effect of diffusion;
step 3, determining the absolute pressure pair SO2The effect of diffusion;
step 4, determining each monitoring point SO of the model2The concentration change condition;
step 5, obtaining the following results through steps 2-4: under the condition of the same pressure and different initial concentrations, the larger the initial concentration is, the longer the time for the diffusion to reach uniformity is; under the conditions of the same concentration absolute pressure of 0.4Mpa and 0.6Mpa respectively, the time for the diffusion to reach uniformity is 5390s and 4800s respectively, and the SF of GIS equipment6SO in the system2The greater the absolute pressure SO upon diffusion2The greater the diffusion rate of (A), SO2The less time is required for diffusion to homogeneity.
Step 2 determining initial concentration vs. SO2The method of influence of diffusion includes: it is assumed that different concentrations of SO are present at the inner edge positions (0, -0.325, 0) of the apparatus body2Gas, the rest being SF6A gas; defining the maximum and minimum concentration difference of characteristic component gas in the equipment to be less than or equal to 1 muL.L-1When the method is used, the gas diffusion of the characteristic components is considered to be uniform; the simulation using FLUENT gave the concentration levels and times at which diffusion reached homogeneity for 10 different initial concentrations, as shown in Table 1:
TABLE 1 different SO2Time and concentration for uniform diffusion at initial concentration
Figure BDA0002918965150000031
SO from Table 12The greater the initial concentration of gas, the longer the time for the diffusion to reach uniformity, and the greater the concentration after the diffusion is uniform.
It still includes: introducing variable C1And C2，C1Indicating the initial concentration of the characteristic component gas, C2Indicating that the characteristic component gas is in SF6Concentration at which diffusion in the electrical apparatus reaches uniformity, C is established1And C2The corresponding concentration size relationship is shown in table 2;
TABLE 2C1And C2Corresponding to the concentration (unit: μ L. L)-1)
Figure BDA0002918965150000032
Describing C by Pearson's correlation coefficient1And C2The correlation coefficient is expressed by r, and the formula is:
Figure BDA0002918965150000041
in the formula: n is the sample size, X and Y respectively represent C1And C2，Xi、YiAnd X, Y are the observed and mean values of the two variables, respectively; r describes the degree of linear correlation strength between two variables; r takes on a value between-1 and +1, if r>0, indicating that the two variables are positively correlated, if r<0, indicating that the two variables are negatively correlated, a larger absolute value of r indicates a stronger correlation.
By means of fitting in Table 2 (C)1，C2) Linear fitting is carried out on 10 points to obtain C1And C2The relational expression between them is as follows:
C1＝147.05C2+6.24 (2)。
step 3 determining the absolute pressure vs. SO2The method of influence of diffusion is: assume that the edge positions (0, -0.325, 0) inside the device are present at a concentration of 500. mu.L.L-1SO of (A)2Gas, absolute pressure of 0.4MPa and 0.6MPa is selected for qualitative and quantitative analysis of SO2The effect of diffusion.
Analysis of absolute pressure vs. SO2The method of influence of diffusion is: observing the section with Z being 0, and under the condition that the absolute pressure in the model is 0.4Mpa, SO2After 1000s of diffusion, SO in the whole tangent plane2The concentration of (A) is less than 9.13. mu.L.L-1，SO2At a concentration of 0.46. mu.L.L-1To 8.68. mu.L.L-1，SO2The concentration of (A) has a concentration gradient from bottom to top, the concentration at the bottom of the device is the highest, the concentration at the top of the device is the lowest, and the concentration difference is 9.13 mu L.L-1(ii) a When the diffusion time reaches 3000s, the whole section SO2The concentration is lower than 4.25 muL.L-1Internal SO of the model2The diffusion is more uniform, the concentration at the right lower part of the device is the highest, the concentration at the gas taking port is the lowest, and the concentration difference is 3.15 mu L.L-1(ii) a The maximum concentration was 3.63. mu.L.L when the diffusion time was 5390s-1The minimum concentration is 2.71. mu.L.L-1The concentration difference is 0.92 mu L.L-1The diffusion is uniform.
Analysis of absolute pressure vs. SO2The method of influence of diffusion is: observing the section with Z being 0, diffusing for 1000s under the condition that the absolute pressure in the model is 0.6Mpa, and collecting SO in the whole section2The concentration of (b) is less than 8.64. mu.L.L-1It shows the highest concentration at the bottom of the apparatus, the lowest concentration at the top of the apparatus, SO2At a concentration of 0.44. mu.L.L-1To 8.21. mu.L.L-1The concentration difference is 8.64 mu L.L-1(ii) a After diffusion for 3000s, SO of the whole section2The concentration of (b) is less than 4.18. mu.L.L-1The concentration below the equipment is highest, the concentration at the position of the gas taking port is lowest, and the concentration difference is 2.97 mu L.L-1(ii) a When the diffusion time was 4800s, the maximum concentration was 3.63. mu.L.L-1The minimum concentration is 2.64. mu.L.L-1The concentration difference is 0.99 mu L.L-1The diffusion is uniform.
It still includes: introducing variable maximum concentration difference deltac to represent the difference between the maximum concentration and the minimum concentration in the whole section at a certain moment; absolute pressure0.4Mpa, and when the diffusion time reaches 3000s, SO2At SF6The distribution conditions in the electrical equipment are consistent, but the concentration is different; absolute pressure of 0.4MPa, SO2After 3000s of diffusion of the gas, Z is 0 section of SO2The maximum concentration of gas is 4.25 muL.L-1The minimum concentration is 1.1. mu.L.L-1The maximum concentration difference Δ c0.4 is 3.15 μ L · L-1(ii) a SO at an absolute pressure of 0.6MPa, again after diffusion for 3000s2The maximum and minimum concentrations in the cut surface were 4.18. mu.L.L-1And 1.21. mu.L.L-1The maximum concentration difference Δ c0.6 is 2.97 μ L · L-1(ii) a By comparing the maximum concentration differences at different absolute pressures, for SO2For gases, the greater the absolute pressure, the smaller the maximum concentration difference; the maximum concentration difference can indirectly reflect SO2The gas is uniformly diffused in the equipment, and the smaller the maximum concentration difference is, the more uniform the diffusion is; SO at absolute pressures of 0.4MPa and 0.6MPa2The time for the gas to diffuse uniformly on the Z-0 section is 5390s and 4800s respectively; thus, an increase in absolute pressure with an increase in SO can be obtained2Gas in SF6Diffusion rate in gas.
Step 4, determining each monitoring point SO of the model2The method for the concentration change condition comprises the following steps:
SO2under the conditions of 0.4Mpa and 0.6Mpa of gas, 14 monitoring points are arranged in the model, the center of the left plane of the geometric model is taken as an origin, and the coordinates of each monitoring point are shown in the following table 3;
TABLE 3 coordinates of monitoring points
Figure BDA0002918965150000061
Monitoring the change rule of the characteristic component gas concentration of 14 monitoring points along with time; to obtain: at the beginning of diffusion, monitoring points SO2SO concentration of 0, at each monitoring point over time2The concentration gradually rises and finally tends to be stable, and the diffusion is uniform;
the monitoring point 9 is selected and,11 and 14 for SO at these three monitoring points2Comparing the concentration change conditions; finally, the following results are obtained: SO (SO)2Under the conditions of 0.4Mpa and 0.6Mpa, the time for the gas to diffuse in the GIS to reach uniformity is 5390s and 4800s, the increase of the pressure improves SO2SO that SO is diffused at a rate such that2The time for the diffusion to be uniform is advanced.
The invention has the beneficial effects that:
the invention uses fluid mechanics (CFD) technology to research SO based on FLUENT simulation2Diffusion effect in GIS equipment, research of SO under different initial concentrations and different absolute pressures2And (3) under the influence of diffusion, fitting to obtain a linear relation between the initial concentration and the concentration when the diffusion is uniform under the same pressure, and providing reference for further judging equipment faults. Meanwhile, SO before, in and after diffusion under different absolute pressure conditions is obtained2At SF6The concentration and the concentration distribution in the electrical equipment provide guidance for monitoring technology in production practice;
in order to study the characteristic fault decomposer SO2In the GIS equipment internal diffusion effect, under the conditions of different initial concentrations and different absolute pressures, the CFD technology simulation software FLUENT is used for obtaining SO2Diffusion properties inside the device. The result shows that under the condition of different initial concentrations at the same pressure, the larger the initial concentration is, the longer the diffusion reaches uniformity. And fitting to obtain a functional relation between the initial concentration and the concentration when the diffusion is uniform, and providing a theoretical basis for further judging the equipment fault. Under the conditions that the absolute pressure of the same concentration is 0.4Mpa and 0.6Mpa respectively, the time for the diffusion to reach uniformity is 5390s and 4800s respectively, which shows that different pressure environments can be applied to the SF of the GIS equipment6SO in the system2Diffusion has a certain influence, the greater the absolute pressure, the greater the SO2The greater the diffusion rate of (A), SO2The less time is required for diffusion to homogeneity. The research of the invention can also be combined with the set monitoring period of the on-line monitoring technology, the service life of the monitoring equipment can be shortened when the monitoring is frequent, and the latent fault can not be detected in time when the monitoring interval time is long, so the invention can also provide theoretical basis for the set monitoring period of the monitoring technology;solves the problem that the characteristic decomposition product SO is not researched by people in the prior art2The diffusion characteristic in the GIS equipment can not provide reference for further judging equipment faults, and the like.
Drawings
FIG. 1 is a graphical illustration comparing linear fit to actual data in an embodiment;
FIG. 2 shows the SO value of 0.4MPa pressure, Z0 and t 1000s2A concentration field schematic;
FIG. 3 shows the pressure conditions of 0.4MPa, Z0 and section t 3000s for SO in the embodiment2A concentration field schematic;
FIG. 4 shows the SO value of 0.4MPa pressure, Z0 and t 5390s2A concentration field schematic;
FIG. 5 shows the SO values of the embodiment under the pressure condition of 0.6MPa, when Z is 0 and t is 1000s2A concentration field schematic;
FIG. 6 shows the pressure conditions of 0.6MPa, and SO when Z is 0 and t is 3000s2A concentration field schematic;
FIG. 7 shows SO obtained when the pressure is 0.6MPa and the section is 0 and t is 4800s in the embodiment2A concentration field schematic;
FIG. 8 shows the monitoring point SO at 0.4MPa in the embodiment2A schematic graph of concentration versus time;
FIG. 9 shows the monitoring point SO at 0.6MPa in the embodiment2A schematic graph of concentration versus time;
FIG. 10 is a graph illustrating the concentration variation at different monitoring points under different absolute pressure conditions according to an embodiment.
Detailed Description
SO in GIS equipment based on CFD technology2A diffusion characteristic determining method, comprising:
step 1, establishing a model and initial conditions
SF6Electric equipment model]Equal proportion modeling, the model is divided into two parts, the lower large cylinder is the equipment body, the upper small cylinder is the gas taking port, the whole geometryThe mold is in a closed configuration. Considering the practical situation, SF6The high-voltage electrical equipment is in a high-voltage environment, so that in the whole simulation process, the absolute pressure inside the model is selected to be 0.4MPa and 0.6MPa, and the temperature is 300K. The simulation calculation is based on an ANSYS FLUENT software platform, grids are divided through an Ansys FLUENT Meshing tool, the number of the grids is 12843, the quality of the grids is more than 0.8, and the requirements are met.
Step 2, determining initial concentration to SO2The effect of diffusion;
to study the different initial concentrations versus SO2Influence of the diffusion situation, assuming different concentrations of SO at the inner edge positions (0, -0.325, 0) of the device body2Gas, the rest being SF6A gas. Defining the maximum and minimum concentration difference of characteristic component gas in the equipment to be less than or equal to 1 muL.L-1In time, it is considered that the characteristic component gas diffusion is uniform. The simulation using FLUENT gave the concentration levels and times at which diffusion reached homogeneity for 10 different initial concentrations, and the results are shown in Table 1 below.
TABLE 1 different SO2Time and concentration for uniform diffusion at initial concentration
Figure BDA0002918965150000091
As can be seen from Table 1, SO2The greater the initial concentration of gas, the longer the time for the diffusion to reach uniformity, and the greater the concentration after the diffusion is uniform, and vice versa. In order to further explore the relationship between the initial concentration and the concentration at which the diffusion becomes uniform, the invention introduces the variable C1And C2，C1Indicating the initial concentration of the characteristic component gas, C2Indicating that the characteristic component gas is in SF6Concentration at which diffusion in the electrical apparatus reaches uniformity, C1And C2The corresponding concentration levels are shown in table 2 below.
TABLE 2C1And C2Corresponding to the concentration (unit: μ L. L)-1)
Figure BDA0002918965150000092
Describing C by Pearson's correlation coefficient1And C2The correlation between them, the pearson correlation coefficient is also called pearson product moment correlation coefficient, and is a linear correlation coefficient. The pearson correlation coefficient is a statistic used to reflect the degree of linear correlation of two variables. The correlation coefficient is represented by r, where n is the sample size, and X and Y represent C, respectively1And C2，Xi、YiAnd X, Y are the observed and mean values of the two variables, respectively. r describes the degree of linear correlation between two variables. r takes on a value between-1 and +1, if r>0, indicating that the two variables are positively correlated, if r<0, indicating that the two variables are negatively correlated, a larger absolute value of r indicates a stronger correlation.
Figure BDA0002918965150000101
Calculating to obtain r as 0.9999, and describing C1And C2There is a strong positive correlation between them. In order to further verify the accuracy of the results,
by means of fitting in Table 2 (C)1，C2) The results of the linear fitting of 10 points are shown in FIG. 1 below.
As can be seen from FIG. 1, the fitting results almost completely coincided with the distribution of the actual data, demonstrating that C1And C2There is a strong linear positive correlation between them. To obtain C1And C2The relational expression between them is as follows:
C1＝147.05C2+6.24 (2)
when SF6When electrical equipment fails, the existing technical means can hardly determine the total content of characteristic component gases generated by the failure, and C is established1And C2The relation between the concentration at the initial moment and the concentration after uniform diffusion is obtained through a mathematical relation between the concentration and the C, and the C can be obtained through online monitoring or offline detection2And then deducing the characteristics of the faultCharacterizing the total content C of the component gas1And providing basis for further judging the severity of the fault.
Step 3, determining the absolute pressure pair SO2The effect of diffusion;
to determine different absolute pressure conditions versus SO2The influence of diffusion, assuming that the edge positions (0, -0.325, 0) inside the device are present at a concentration of 500. mu.L.L-1SO of (A)2Gas, absolute pressure of 0.4MPa and 0.6MPa is selected for qualitative and quantitative analysis of SO2The effect of diffusion. When diffusion begins, SO is distributed in the equipment along with the time2In order to observe the concentration distribution and change condition inside the equipment more intuitively, a section with Z being 0 is taken, and the concentration distribution cloud chart is shown in FIGS. 2-7.
As can be seen from FIGS. 2 to 7, SO was observed at an absolute pressure of 0.4MPa in the interior of the mold2After 1000s of diffusion, SO in the whole tangent plane2The concentration of (A) is less than 9.13. mu.L.L-1，SO2Mainly at a concentration of 0.46. mu.L.L-1To 8.68. mu.L.L-1，SO2The concentration distribution of the active carbon also presents a certain regularity, the concentration has an obvious concentration gradient from bottom to top, the concentration at the bottom of the equipment is highest, the concentration at the top of the equipment is lowest, and the concentration difference is 9.13 mu L.L-1. When the diffusion time reaches 3000s, the whole section SO2The concentration is lower than 4.25 muL.L-1Internal SO of the model2The diffusion is more uniform, the concentration at the right lower part of the device is the highest, the concentration at the gas taking port is the lowest, and the concentration difference is 3.15 mu L.L-1. The maximum concentration was 3.63. mu.L.L when the diffusion time was 5390s-1The minimum concentration is 2.71. mu.L.L-1The concentration difference is 0.92 mu L.L-1The diffusion is uniform.
Diffusing for 1000s under the condition that the absolute pressure in the model is 0.6Mpa, and then collecting SO in the whole tangent plane2The concentration of (b) is less than 8.64. mu.L.L-1Still present the highest concentration at the bottom of the apparatus, the lowest concentration at the top of the apparatus, SO2Mainly at a concentration of 0.44. mu.L.L-1To 8.21. mu.L.L-1The concentration difference is 8.64 mu L.L-1. When diffusing 30SO of whole section after 00s2The concentration of (b) is less than 4.18. mu.L.L-1The concentration below the equipment is highest, the concentration at the position of the gas taking port is lowest, and the concentration difference is 2.97 mu L.L-1. When the diffusion time was 4800s, the maximum concentration was 3.63. mu.L.L-1The minimum concentration is 2.64. mu.L.L-1The concentration difference is 0.99 mu L.L-1The diffusion is uniform.
To further determine the absolute pressure vs. SO2Gas in SF6The influence of the diffusion rate in the gas introduces a variable maximum concentration difference ac, which represents the difference between the maximum concentration and the minimum concentration in the entire section at a certain moment. As can be seen from a comparison of FIGS. 3 and 6, when the diffusion time reached 3000s, the SO content was increased2At SF6The distribution condition in the electrical equipment is basically consistent, but the concentration magnitude is different. As can be seen from FIG. 3, SO was obtained at an absolute pressure of 0.4MPa2After 3000s of diffusion of the gas, Z is 0 section of SO2The maximum concentration of gas is 4.25 muL.L-1The minimum concentration is 1.1. mu.L.L-1The maximum concentration difference Δ c0.4 is 3.15 μ L · L-1. In FIG. 6, SO was diffused for 3000 seconds2The maximum and minimum concentrations in the cut surface were 4.18. mu.L.L-1And 1.21. mu.L.L-1The maximum concentration difference Δ c0.6 is 2.97 μ L · L-1. By comparing the maximum concentration differences at different absolute pressures, it can be seen that for SO2For gases, the greater the absolute pressure, the smaller the maximum concentration difference. The maximum concentration difference can indirectly reflect SO2The gas diffuses uniformly inside the device, and the smaller the maximum concentration difference, the more uniform the diffusion. SO at absolute pressures of 0.4MPa and 0.6MPa2The time for the gas to diffuse uniformly in the Z-0 section was 5390s and 4800s, respectively. Therefore, as can be seen from the above analysis, the increase in absolute pressure increases SO2Gas in SF6Diffusion rate in gas.
Step 4, determining each monitoring point SO of the model2The concentration change condition;
to further study the absolute pressure vs SO2Influence of diffusion in GIS and simultaneous SO at different positions in equipment2The concentration distribution is quantitatively analyzed, 14 monitoring points are arranged in the model, the center of the left plane of the geometric model is used as an original point, and the coordinates of each monitoring point are shown in the following table 3.
TABLE 3 coordinates of monitoring points
Figure BDA0002918965150000131
The time-dependent behavior of the characteristic component gas concentrations at these 14 monitoring points was monitored under the above conditions, and the results are shown in FIGS. 8 and 9 below. As is evident from FIGS. 8 and 9, the monitoring points SO are at different absolute pressures2The concentration variation characteristics are not very different. SO of monitoring point 112The concentration has the most severe trend, the monitoring points 9, 12 and 13 have the second trend, and the monitoring point 14 has the SO2Minimal concentration fluctuation, SO of other monitoring points2The concentration has less tendency to change. Bound SO2The concentration changes of the diffusion path and each monitoring point can be found out2The whole diffusion path is diffused rightwards from the left lower edge of the device and then upwards from the bottom of the device. The monitoring point 11 is located at the lower right edge of the device, SO2Spread out to this location first, SO the trend of the monitoring point 11 is the most drastic, the monitoring points 9, 12, 13 are located in the rightmost plane of the device Y-0, SO2Concentration fluctuations are then followed by the monitor point 14 being furthest from the initial diffusion site, SO2The concentration change is minimum, and the fluctuation difference of other monitoring points is not large. Throughout the diffusion process, each monitoring point SO is in a short period of time after the diffusion begins2SO concentration of 0, at each monitoring point over time2The concentration gradually rises and finally tends to be stable, and the diffusion is uniform.
From the above analysis, SO at each monitoring point2The concentration change situation is different from the positions of the monitoring points, but the overall change trend is that the concentration rises along with the time and finally becomes stable. For more convenient comparison of different absolute pressures to SO2The influence of diffusion, 3 representative monitoring points were selected from the above 14 monitoring points,the selected monitoring points are 9, 11 and 14, and SO is applied to the three monitoring points2The concentration changes were compared, and the comparison results are shown in FIG. 10.
As can be seen from FIG. 10, the monitoring points 9 and 11 showed a large concentration variation within 2000s from the start of diffusion, and under the absolute pressure condition of 0.4MPa, the variation trends of the monitoring points 9 and 11 were both increased and then decreased, with the maximum concentrations of 5. mu.L.L-1And 9. mu.L.L-1Under the pressure condition of 0.6MPa, the concentration change trends of the monitoring points 9 and 11 are similar to those of the monitoring points at 0.4MPa, but the maximum concentrations are respectively 5.6 muL.L-1And 10.2. mu.L.L-1And for the monitoring point 14, the SO thereof is no matter whether the absolute pressure is 0.4MPa or 0.6MPa2The concentration was almost 0. In the following diffusion time, at an absolute pressure of 0.4MPa, monitoring points 9 and 11SO2The concentration slowly decreases and eventually stabilizes. Monitoring point 14SO2The concentration slowly increases, and when the concentration is diffused to 10000s, the concentration is stabilized at 3.4 muL.L-1Is measured at one level. The final concentration was maintained at 3.4. mu.L.L steadily at an absolute pressure of 0.6MPa, similar to the pressure of 0.4MPa-1。
The invention gives the concentration at each moment under different absolute pressures and each monitoring point SO2Specific data for concentration changes are shown in tables 4 and 5 below.
TABLE 40.4 Mpa SO at different time points2Concentration of
Figure BDA0002918965150000141
Table 50.6 Mpa, SO at different time points2Concentration of
Figure BDA0002918965150000142
Figure BDA0002918965150000151
Under the conditions of absolute pressures of 0.4Mpa and 0.6Mpa, obtaining the concentration and distribution contrast of a 0 section Z under different absolute pressures based on FLUENT simulation, and simultaneously carrying out comparative analysis on 14 monitoring points and 3 representative monitoring points SO2The concentration is changed regularly with time. Can give out SO2Under the conditions of 0.4Mpa and 0.6Mpa, the time for the gas to diffuse in the GIS to reach uniformity is 5390s and 4800s, the increase of the pressure improves SO2SO that SO is diffused at a rate such that2The time for even diffusion is advanced, but the change of the absolute pressure to SO can be known from the concentration distribution cloud chart and the concentration change of each monitoring point2The influence of diffusion is very limited.
The diffusion characteristic determination method of the present invention is equally applicable to H2S、SOF2、SO2F2Or determining the gas diffusion characteristic of decomposition products such as HF and the like in the GIS equipment.

Claims (9)

1. SO in GIS equipment based on CFD technology2A diffusion characteristic determining method, comprising:
step 1, to SF6The electrical equipment model is modeled in equal proportion, the model is divided into two parts, a lower cylinder is an equipment body, an upper cylinder is an air intake port, and the whole geometric model is of a closed structure;
step 2, determining initial concentration to SO2The effect of diffusion;
step 3, determining the absolute pressure pair SO2The effect of diffusion;
step 4, determining each monitoring point SO of the model2The concentration change condition;
step 5, obtaining the following results through steps 2-4: under the condition of the same pressure and different initial concentrations, the larger the initial concentration is, the longer the time for the diffusion to reach uniformity is; under the conditions of the same concentration absolute pressure of 0.4Mpa and 0.6Mpa respectively, the time for the diffusion to reach uniformity is 5390s and 4800s respectively, and the SF of GIS equipment6SO in the system2The greater the absolute pressure SO upon diffusion2The greater the diffusion rate of (A), SO2The less time is required for diffusion to homogeneity.
2. SO in GIS equipment based on CFD technology according to claim 12A diffusion characteristic determination method, characterized by: step 2 determining initial concentration vs. SO2The method of influence of diffusion includes: it is assumed that different concentrations of SO are present at the inner edge positions (0, -0.325, 0) of the apparatus body2Gas, the rest being SF6A gas; defining the maximum and minimum concentration difference of characteristic component gas in the equipment to be less than or equal to 1 muL.L-1When the method is used, the gas diffusion of the characteristic components is considered to be uniform; the simulation using FLUENT gave the concentration levels and times at which diffusion reached homogeneity for 10 different initial concentrations, as shown in Table 1:
TABLE 1 different SO2Time and concentration for uniform diffusion at initial concentration
Figure FDA0002918965140000021
SO from Table 12The greater the initial concentration of gas, the longer the time for the diffusion to reach uniformity, and the greater the concentration after the diffusion is uniform.
3. SO in GIS equipment based on CFD technology according to claim 22A diffusion characteristic determination method, characterized by: it still includes: introducing variable C1And C2，C1Indicating the initial concentration of the characteristic component gas, C2Indicating that the characteristic component gas is in SF6Concentration at which diffusion in the electrical apparatus reaches uniformity, C is established1And C2The corresponding concentration size relationship is shown in table 2;
TABLE 2C1And C2Corresponding to the concentration (unit: μ L. L)-1)
Figure FDA0002918965140000022
Describing C by Pearson's correlation coefficient1And C2Correlation between, correlation coefficientExpressed as r, the formula is:
Figure FDA0002918965140000023
in the formula: n is the sample size, X and Y respectively represent C1And C2，Xi、YiAnd
Figure FDA0002918965140000031
respectively are the observed value and the mean value of the two variables; r describes the degree of linear correlation strength between two variables; r takes on a value between-1 and +1, if r>0, indicating that the two variables are positively correlated, if r<0, indicating that the two variables are negatively correlated, a larger absolute value of r indicates a stronger correlation.
4. SO in GIS equipment based on CFD technology according to claim 32A diffusion characteristic determination method, characterized by: it still includes: by means of fitting in Table 2 (C)1，C2) Linear fitting is carried out on 10 points to obtain C1And C2The relational expression between them is as follows:
C1＝147.05C2+6.24 (2)。
5. SO in GIS equipment based on CFD technology according to claim 12A diffusion characteristic determination method, characterized by: step 3 determining the absolute pressure vs. SO2The method of influence of diffusion is: assume that the edge positions (0, -0.325, 0) inside the device are present at a concentration of 500. mu.L.L-1SO of (A)2Gas, absolute pressure of 0.4MPa and 0.6MPa is selected for qualitative and quantitative analysis of SO2The effect of diffusion.
6. SO in GIS equipment based on CFD technology according to claim 52A diffusion characteristic determination method, characterized by: analysis of absolute pressure vs. SO2The method of influence of diffusion is: taking Z ═Observing the section of the mold with SO under the condition of 0.4Mpa of absolute pressure2After 1000s of diffusion, SO in the whole tangent plane2The concentration of (A) is less than 9.13. mu.L.L-1，SO2At a concentration of 0.46. mu.L.L-1To 8.68. mu.L.L-1，SO2The concentration of (A) has a concentration gradient from bottom to top, the concentration at the bottom of the device is the highest, the concentration at the top of the device is the lowest, and the concentration difference is 9.13 mu L.L-1(ii) a When the diffusion time reaches 3000s, the whole section SO2The concentration is lower than 4.25 muL.L-1Internal SO of the model2The diffusion is more uniform, the concentration at the right lower part of the device is the highest, the concentration at the gas taking port is the lowest, and the concentration difference is 3.15 mu L.L-1(ii) a The maximum concentration was 3.63. mu.L.L when the diffusion time was 5390s-1The minimum concentration is 2.71. mu.L.L-1The concentration difference is 0.92 mu L.L-1The diffusion is uniform.
7. SO in GIS equipment based on CFD technology according to claim 52A diffusion characteristic determination method, characterized by: analysis of absolute pressure vs. SO2The method of influence of diffusion is: observing the section with Z being 0, diffusing for 1000s under the condition that the absolute pressure in the model is 0.6Mpa, and collecting SO in the whole section2The concentration of (b) is less than 8.64. mu.L.L-1It shows the highest concentration at the bottom of the apparatus, the lowest concentration at the top of the apparatus, SO2At a concentration of 0.44. mu.L.L-1To 8.21. mu.L.L-1The concentration difference is 8.64 mu L.L-1(ii) a After diffusion for 3000s, SO of the whole section2The concentration of (b) is less than 4.18. mu.L.L-1The concentration below the equipment is highest, the concentration at the position of the gas taking port is lowest, and the concentration difference is 2.97 mu L.L-1(ii) a When the diffusion time was 4800s, the maximum concentration was 3.63. mu.L.L-1The minimum concentration is 2.64. mu.L.L-1The concentration difference is 0.99 mu L.L-1The diffusion is uniform.
8. SO in GIS equipment based on CFD technology according to claim 6 or 72A diffusion characteristic determination method, characterized by: it still includes: guiding deviceThe maximum concentration difference Delta c of the input variables represents the difference between the maximum concentration and the minimum concentration in the whole section at a certain moment; absolute pressure of 0.4Mpa, diffusion time of 3000s, SO2At SF6The distribution conditions in the electrical equipment are consistent, but the concentration is different; absolute pressure of 0.4MPa, SO2After 3000s of diffusion of the gas, Z is 0 section of SO2The maximum concentration of gas is 4.25 muL.L-1The minimum concentration is 1.1. mu.L.L-1The maximum concentration difference Δ c0.4 is 3.15 μ L · L-1(ii) a SO at an absolute pressure of 0.6MPa, again after diffusion for 3000s2The maximum and minimum concentrations in the cut surface were 4.18. mu.L.L-1And 1.21. mu.L.L-1The maximum concentration difference Δ c0.6 is 2.97 μ L · L-1(ii) a By comparing the maximum concentration differences at different absolute pressures, for SO2For gases, the greater the absolute pressure, the smaller the maximum concentration difference; the maximum concentration difference can indirectly reflect SO2The gas is uniformly diffused in the equipment, and the smaller the maximum concentration difference is, the more uniform the diffusion is; SO at absolute pressures of 0.4MPa and 0.6MPa2The time for the gas to diffuse uniformly on the Z-0 section is 5390s and 4800s respectively; thus, an increase in absolute pressure with an increase in SO can be obtained2Gas in SF6Diffusion rate in gas.
9. SO in GIS equipment based on CFD technology according to claim 12A diffusion characteristic determination method, characterized by: step 4, determining each monitoring point SO of the model2The method for the concentration change condition comprises the following steps:
SO2under the conditions of 0.4Mpa and 0.6Mpa of gas, 14 monitoring points are arranged in the model, the center of the left plane of the geometric model is taken as an origin, and the coordinates of each monitoring point are shown in the following table 3;
TABLE 3 coordinates of monitoring points
Figure FDA0002918965140000051
Monitor 14 monitorsMeasuring the rule of the change of the characteristic component gas concentration along with time; to obtain: at the beginning of diffusion, monitoring points SO2SO concentration of 0, at each monitoring point over time2The concentration gradually rises and finally tends to be stable, and the diffusion is uniform;
selecting monitoring points 9, 11 and 14 for SO at the three monitoring points2Comparing the concentration change conditions;
finally, the following results are obtained: SO (SO)2Under the conditions of 0.4Mpa and 0.6Mpa, the time for the gas to diffuse in the GIS to reach uniformity is 5390s and 4800s, the increase of the pressure improves SO2SO that SO is diffused at a rate such that2The time for the diffusion to be uniform is advanced.
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