CN112924326B - An Improved Method of Pollution Classification Based on Soluble Pollution Components - Google Patents

Abstract

The invention belongs to the technical field of high voltage and insulation, and particularly relates to a pollution classification improvement method based on soluble pollution components; the technical points are as follows: sampling a pollution site, testing the composition and the mass fraction of soluble chemical components, calculating an equivalent salt density test value and an equivalent ash density test value, then correcting the equivalent salt density test value to obtain an equivalent salt density value, and finally grading the pollution by using the equivalent salt density value and the equivalent ash density test value. The pollution grading improvement method based on the soluble pollution component comprehensively considers the conductive characteristic and the difficult-to-handle characteristic of the complex pollution component, is more practical in pollution degree evaluation, and can accurately obtain the tolerance capacity of the insulator under pollution, thereby providing a more practical method for design and evaluation of external insulation configuration.

Description

An Improved Method of Pollution Classification Based on Soluble Pollution Components

technical field

The invention belongs to the technical field of high voltage and insulation, and in particular relates to an improved method for classifying pollution levels based on soluble pollution components.

Background technique

Before determining the external insulation level of the transmission line, the pollution level of the operating environment of the insulator must be determined first. Therefore, it is very important to correctly divide the pollution level and take countermeasures that match the pollution level in different regions according to the pollution level. At present, there are many characteristic quantities that characterize the operating state of polluted insulators, and because the equivalent salt density has a good correlation with the flashover voltage of polluted insulator strings, and it has the longest history of use among the pollution level classification methods adopted in China, It is the method with the most common application, the most accumulated data, and the most summed up experience, so it is the main measurement method adopted by the power operation department.

In addition, the existing research results at home and abroad show that insoluble pollution, that is, ash density, has a certain impact on the AC pollution flashover voltage of insulator strings. When dividing pollution levels, the influence of ash density should be fully considered. Therefore, IEC 60815 (new) proposes the following Salt density and gray density are used as pollution characteristic quantities to classify pollution levels. This standard is proposed on the basis of on-site measurement, operating experience and pollution test, and considering the characteristics of insulator pollution. The division should be more reasonable. In this standard, each pollution level does not change suddenly from one level to another level, but transitions between adjacent pollution levels, so it is important for determining the external insulation strength of transmission lines that should be configured in certain areas D. Then, the external insulation configuration of the polluted area can be checked by using the pollution level measured on site. IEC-60815 stipulates the corresponding uniform creepage ratio value under each pollution level, combined with the number of on-site insulators and the degree of pollution, the insulation margin can be calculated to evaluate the safety of the external insulation configuration in the area.

However, pollution components have a significant impact on the pollution flashover characteristics of insulators, and the traditional pollution level classification only takes the equivalent salt density and gray density as a reference, which fails to reflect the pollution flashover characteristics of insulators under real operating conditions. Pollution has certain drawbacks. For example, due to the combustion of boilers and exhaust gas emissions, the pollution components in industrial dust areas are complex and contain more nitrates, so that the external insulation configuration of overhead lines near this area is seriously affected by pollution. In recent years, the discharge of overhead line insulators has frequently occurred in heavy industrial dust areas , flashover, deterioration and ablation, etc., seriously endanger the safe and stable operation of the power system.

Existing research results have shown that under the same equivalent salt density, the flashover voltage values of insulators corresponding to different pollution components are different; and only based on the measured ESDD value and ESDD-Uf negative power exponent relationship to predict the insulator under the mixed composition The flashover voltage has a percentage error of 40% from the actual test value. Therefore, in the on-site pollution test, only by measuring the equivalent salt density and ash density, it is not possible to characterize the pollution degree of the polluted area and the electrical performance of the insulator under the pollution condition.

In view of the above-mentioned defects in the prior art, based on years of rich experience and professional knowledge in this type of material, the inventor cooperates with theoretical analysis, researches and innovates, and develops an improved method for the division of pollution levels based on soluble pollution components, which can be more accurate. Actual characterizes the outer insulation configuration margin of the divided area.

Contents of the invention

The purpose of the present invention is to provide an improved method for the division of pollution grades based on soluble pollution components. By sampling the pollution on-site, the composition and mass fraction of soluble chemical components are obtained by ion chromatography analysis, and the equivalent salt density test value and ash density are calculated. Then the equivalent salt density test value is corrected to obtain the equivalent salt density value, and finally the pollution level is divided by the equivalent salt density value and the gray density test value.

Further, the following steps are included:

S1. On-site pollution test;

S2. Pollution flashover voltage correction;

S3. Equivalent salt density value conversion.

Further, the specific operation of step S1 is as follows: collect the contamination on the surface of the insulator, fully dissolve the collected contamination, and then filter to obtain the filtrate and filter residue; the filtrate is bottled after constant volume, and the filter residue is weighed after drying, and its weight Divide by the surface area of the insulator to get the gray density test value NSDD _M , unit mg/cm ² ; conduct conductivity test on the filtrate, calculate the equivalent salt density test value ESDD _M according to the solution volume, conductivity, and insulator surface area, unit mg/cm ² ; At the same time, a part of the filtrate was taken out for ion chromatographic analysis to obtain the anion and cation components and their mass fractions, and then the ion components were paired based on the fuzzy clustering method to obtain the compound composition i and βi. Specifically, to collect the dirt on the surface of the insulator, wipe the insulator on site with a paper towel, then rinse the wiped paper towel to fully dissolve the dirt, and then obtain the filtrate and filter residue by filtration.

Further, since the flashover voltage of an insulator is significantly affected by its pollution components, under the same equivalent salt density, the flashover voltage gradient corresponding to the mixed pollution components is very different from the flashover voltage gradient under a single sodium chloride. Therefore, the present invention Combining the pollution chemical components obtained in step S1 to correct the pollution flashover voltage, so the specific operation of step S2 is as follows: according to the compound components and their mass fractions, prepare three solutions of soluble pollution components with different conductivity, and use kaolin to adjust the solution to make it Viscous, the purpose is to use kaolin to simulate the gray density of insulators; the insulators are polluted by the dipping method, and a group of test samples are taken every time they are polluted to measure their equivalent salt density ESDD value, the unit is mg/cm ² , and the rest of the samples are carried out. Artificial pollution test, and then obtain the insulator flashover voltage values under three different ESDD values; carry out the negative power exponential function fitting of the insulator flashover voltage values under three different ESDD values, and obtain the insulator flashover voltage of mixed soluble components Calculation formula: U _mix ＝A×ESDD ^-n ; where ESDD is the equivalent salt density; A is the coefficient related to the form of the insulator; n is the characteristic index of mixed pollution influence, and ESDD _M is brought into the above formula to get the mixed composition Pollution flashover voltage correction result Umix*, unit KV.

Further, the amount of kaolin added is controlled so that the ratio of the mass of kaolin to the mass of pollution is equal to NSDD _M /ESDD _M . The purpose of using kaolin to blend the soluble pollutant components is to make the salt density value of the mixed dirty components after blending equal to the salt density value in step S1.

Furthermore, since the ESDD _M value obtained from the general pollution degree test is obtained based on the conversion of the conductivity of sodium chloride, it cannot characterize the electrical characteristics of the insulation under mixed pollution components, so the specific operation of step S3 is: according to the insulator pollution under mixed pollution components The ESDD _M value obtained from the voltage test is equivalently converted.

得到混合污秽成为对应的等价盐密值(ESDD)^*的表达公式

进而得到公式

其中，式中ESDD是等值盐密值，A₀是可溶物为氯化钠时，与绝缘子形式有关的系数，n₀是可溶物为氯化钠时的污秽影响特征指数，m₀是灰密影响特征指数。Further, the specific steps of the equivalent conversion in step S3 are as follows: According to the flashover characteristics of the insulator under sodium chloride, the formula

Get mixed pollution to become the expression formula of corresponding equivalent salt density value (ESDD) ^*

and then get the formula

Among them, ESDD is the equivalent salt density value, A ₀ is the coefficient related to the form of insulator when the soluble matter is sodium chloride, n ₀ is the pollution influence characteristic index when the soluble matter is sodium chloride, m ₀ is the characteristic index of gray density influence.

Further, the flashover characteristics of the insulator under sodium chloride in step S3 are obtained by consulting the basic data of the insulator.

Furthermore, ESDD* reflects the equivalent salt density value ESDD* corresponding to the measured salt density value (ESDD _M ) of mixed pollution components under the same flashover voltage. Using ESDD* and NSDD _M and the pollution level division diagram in IEC-60815, an improved pollution level that can better characterize the actual electrical strength of the external insulation can be obtained.

In summary, the present invention has the following beneficial effects:

The improved pollution level division method based on soluble pollution components provided by the present invention comprehensively considers the conductive characteristics and tolerance characteristics of complex pollution components, so that the evaluation of pollution degree is more realistic and can accurately obtain the resistance of insulators under pollution. To provide a more practical method for the design and evaluation of external insulation configurations.

Description of drawings

Fig. 1 is a concrete flow chart of the present invention;

Figure 2 is the pollution level division diagram in IEC-60815;

Fig. 3 is a pollution level classification diagram of the present invention.

Detailed ways

In order to further explain the technical means and effects adopted by the present invention to achieve the intended purpose of the invention, an improved method for the classification of pollution levels based on soluble pollution components proposed according to the present invention, its specific implementation, features and effects, are described in detail. The description is as follows.

Example

Taking the mixed pollution components in a typical area as an example, and setting the pollution accumulation test as a certain type of glass insulator (the structural parameters are shown in Table 1), use this method to divide the pollution level. The specific operation is as follows:

S1. Wipe the dirt on the surface of the insulator on site for pollution collection, rinse the wiped paper towel to fully dissolve the pollution, and then filter to obtain the filtrate and filter residue; the filtrate is bottled after constant volume, and the filter residue is weighed after drying, and its weight is divided by the surface area of the insulator Obtain the gray density test value NSDD _M , unit mg/cm ² ; carry out the conductivity test on the filtrate after bottling, and obtain the equivalent salt density test value ESDD _M according to the solution volume, conductivity, and surface area of the insulator;

At the same time, a part of the filtrate was taken out for ion chromatography analysis to obtain the anion and cation components and their mass fractions, and then the ion components were paired based on the fuzzy clustering method to obtain the composition ratio of the main compound composition. The specific results are shown in Table 2;

S2. According to the composition of the compound and its mass fraction, configure three solutions of soluble pollutant components with different conductivity, and use kaolin to adjust the solution to make it viscous; use the dipping method to stain the insulator, and take a group each time it is polluted Test the equivalent salt density ESDD value of the test sample, the unit is mg/cm ² , carry out the artificial pollution test for the rest of the test samples, and then obtain the insulator flashover voltage values under three different ESDD values; carry out the insulator flashover voltage values under three different ESDD values By fitting the negative power exponential function of the network voltage value, the calculation formula for the flashover voltage of the insulator with mixed soluble components is obtained: U _mix ＝A×ESDD ^-n ; where ESDD is the equivalent salt density; A is the coefficient related to the form of the insulator ; n is the mixed pollution impact characteristic index, put ESDD _M into the above formula to get the pollution flashover voltage correction result Umix* under mixed components, unit KV.

得到混合污秽成为对应的等价盐密值(ESDD)^*的表达公式

进而得到公式

其中，式中ESDD是等值盐密值，A₀是可溶物为氯化钠时，与绝缘子形式有关的系数，n₀是可溶物为氯化钠时的污秽影响特征指数，m₀是灰密影响特征指数。S3. Perform equivalent conversion based on the ESDD _M value obtained from the pollution voltage test of the insulator under mixed pollution components. The specific steps are as follows: According to the flashover characteristics of the insulator under sodium chloride, the formula is obtained

Get mixed pollution to become the expression formula of corresponding equivalent salt density value (ESDD) ^*

and then get the formula

Among them, ESDD is the equivalent salt density value, A ₀ is the coefficient related to the form of insulator when the soluble matter is sodium chloride, n ₀ is the pollution influence characteristic index when the soluble matter is sodium chloride, m ₀ is the characteristic index of gray density influence.

For the type of glass insulator provided in this example, the relationship between its flashover voltage and ESDD negative power exponent under sodium chloride can be expressed as: U _f =18×ESDD ^-0.34 , combined with the results in Table 2 , according to the artificial flashover characteristic test under mixed soluble pollution components, the flashover voltage correction result Umix* can be obtained, and the equivalent salt density value ESDD* corresponding to the mixed pollution components can be obtained. The specific results are shown in Table 3.

Table 1 Structural parameters of line insulators in this embodiment

Table 2 Mixed pollution component distribution and pollution degree in typical areas of this embodiment

Table 3 The mixed pollution component flashover voltage correction results Umix* and equivalent salt density value ESDD* in typical areas of this example

For the pollution characteristic parameters in Table 3, according to the measured values of the pollution degree before and after the improved pollution level division method, the pollution level is divided and compared, as shown in Table 4 and Figure 3:

Table 4 Contrast of Pollution Classification Results

It can be seen from Table 4 that the pollution level of half of the test points has dropped by one level with the improved pollution level division method. It can be seen from Figure 1 that for the pollution components and insulator samples configured according to the characteristics of pollution components in typical areas, the pollution level SPS measured by the traditional IEC-60815 pollution level division method is between de; and after the improved division method is used, its Pollution level SPS ^* is between cd, obviously lower than SPS value.

To sum up, it can be concluded that the pollution level of the test point will be overestimated if the pollution degree is evaluated according to the measured value of the equivalent salt density of the sewage sample. However, the improved pollution level classification method is adopted, which comprehensively considers the conductive characteristics and insoluble characteristics of complex pollution components, so that the pollution degree evaluation is more realistic, and the tolerance of insulators under pollution can be accurately obtained, so as to provide a basis for the design of external insulation configuration. And evaluation provides parameter reference.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been shown above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify them into equivalent embodiments with equivalent changes. Technical Essence of the Invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (6)

1. A method for improving the classification of pollution grades based on soluble pollution components, characterized in that, by sampling the pollution site, testing soluble chemical components and mass fractions, calculating equivalent salt density test values and ash density test values, and then The equivalent salt density test value is corrected to obtain the equivalent salt density value, and finally the pollution is graded according to the equivalent salt density value and the gray density test value; Specifically include the following steps: S1. On-site pollution test; S2. Pollution flashover voltage correction; S3. Equivalent salt density value conversion; The specific operation of the step S1 is as follows: collect the dirt on the surface of the insulator, fully dissolve the collected dirt, and then filter to obtain the filtrate and filter residue; the filtrate is bottled after constant volume, and the filter residue is weighed after drying, and its weight The gray density test value NSDD _M is obtained from the surface area of the insulator, and the unit is mg/cm ² ; the conductivity test is carried out on the filtrate, and the equivalent salt density test value ESDD _M is calculated according to the solution volume, conductivity, and the surface area of the insulator, and the unit is mg/cm ² ; At the same time, a part of the filtrate was taken out for ion chromatography analysis to obtain the anion and cation components and their mass fractions, and then the ion components were paired based on the fuzzy clustering method to obtain the compound composition i and βi; The specific operation of the step S2 is as follows: according to the compound components and their mass fractions, configure three solutions of soluble pollutant components with different conductivity, and use kaolin to reconcile the solution to make it viscous; use the dipping method to stain the insulator , take a group of test samples to measure their equivalent salt density ESDD value each time they are polluted, the unit is mg/cm ² , the test method is the same as the above step 1, the other samples are carried out artificial pollution test, and then three different ESDD values are obtained The insulator flashover voltage value; the negative power exponential function fitting of the insulator flashover voltage value under three different ESDD values, and the calculation formula of the insulator flashover voltage with mixed pollution components is obtained: U _mix ＝A×ESDD ^-n ; formula where ESDD is the equivalent salt density; A is the coefficient related to the form of the insulator; n is the mixed pollution influence characteristic index, and ESDD _M is brought into the above formula to obtain the pollution flashover voltage correction result Umix* under mixed pollution components, in KV. 2. according to claim 1, a kind of method for improving the classification of pollution levels based on soluble pollution components, is characterized in that, the ratio of the quality of kaolin to control the quality of kaolin and the quality of soluble pollution components in step 2 is equal to NSDD _M /ESDD _M. 3. A method for improving the classification of pollution levels based on soluble pollution components according to claim 1 or 2, characterized in that the specific operation of the step S3 is: obtained according to the insulator pollution voltage test under the mixed pollution components ESDD _M value for equivalent conversion. 4. A kind of pollution grade division improvement method based on soluble pollution component according to claim 3, it is characterized in that, the concrete step of the equivalent conversion in the described step S3 is as follows: according to the flashover of the insulator under sodium chloride Network characteristics, get the formula

Then the mixed pollution becomes the corresponding equivalent salt density value (ESDD) ^* expression formula:

and then get the formula

Among them, ESDD is the equivalent salt density, A ₀ is the coefficient related to the form of insulator when the soluble matter is sodium chloride, n ₀ is the characteristic index of pollution influence when the soluble matter is sodium chloride, m ₀ is Gray dense influence feature index. 5. A method for improving the classification of pollution levels based on soluble pollution components according to claim 4, characterized in that the flashover characteristics of the insulator in the step S3 under sodium chloride are obtained by consulting the basic data of the insulator of. 6. According to claim 1, a method for improving the classification of pollution levels based on soluble pollution components, is characterized in that, the specific operation of the artificial pollution experiment is to connect the polluted insulator into the high-voltage test circuit, The applied voltage is continuously increased until the insulator flashes over.

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