This standard specifies the artificial pollution test method for porcelain and glass high-voltage insulators for DC systems (solid layer method). This standard applies to the pollution tolerance test of insulators for DC systems with voltages of ±1~500kV and outdoor pollution environments. This standard applies to DC overhead lines, traction lines and substation insulators. It is also applicable to bushings, but the insulation inside should not be damaged. This standard is not directly applicable to composite insulators and other special types of insulators. JB/T 6747-1993 Artificial pollution test method for high-voltage insulators for DC systems (solid layer method) JB/T6747-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T6747-1993
Artificial pollution test method for high-voltage insulators for DC systems
Published on August 21, 1993
Ministry of Machinery Industry of the People's Republic of China
Solid layer method
Implementation on October 1, 1993
Mechanical Industry Standard of the People's Republic of China
Artificial pollution test method for high-voltage insulators for DC systems
Solid layer method
Subject content and scope of application
JB/T6747-1993
This standard specifies the artificial pollution test method for porcelain and glass high-voltage insulators (hereinafter referred to as insulators) for DC systems (solid layer method). This standard applies to the pollution tolerance test of insulators for DC systems with a voltage of ±1 to 500 kV and outdoor pollution environments. This standard applies to insulators for DC overhead lines, traction lines and substations. It also applies to galvanic tubes, but the insulation inside them should not be damaged. This standard does not directly apply to composite insulators and other special types of insulators (semi-conductive glaze insulators or insulators coated with organic materials).
Note: This standard applies to artificial pollution transfer tests at the test site with a drop height of no more than 1000m. Reference standards
High voltage test technology
High voltage test technology
Electrical terminology
GB2900.19 Electrical terminology
3 Terms
Part I
Part III
Insulators
General test requirements
Measuring devices
High voltage test technology and insulation coordination
Artificial pollution transfer test method for high voltage insulators for AC systems Solid layer method
3.1 The terms used in this standard, except those specified in this standard, shall comply with the relevant reference standards. 3.2 Unit test
A single process in which the test object withstands a certain pollution transfer degree and a certain test voltage for a certain period of time or flashover occurs. 3.3 Actual average voltage (U.)
The actual average voltage is the average voltage within a week of the AC voltage ending at this moment. 3.4 Ripple factor
Ratio of ripple amplitude to actual average voltage, i.e. Us/U (Figure 1). 3.5 Test voltage (U,)
Actual average voltage to be applied at the beginning of unit test, 3.6
Voltage drop (△U,)
Difference between the two when the test voltage is higher than the actual average voltage (Figure 2). Approved by the Ministry of Machinery Industry on August 21, 1993
Implemented on October 1, 1993
JB/T6747-1993
LA-AAA-IM
Pulsation amplitude U=M/2
Actual average voltage Ua
Resistive load
Current 100mA
Figure 1 Pulsation amplitude and actual average voltage
Electric bottom overshoot
Voltage drop AU
One cycle of AC voltage
Test voltage Ut
Actual average voltage Ua
Leakage current
Voltage overshoot
Figure 2 Voltage drop and voltage overshoot under corresponding leakage current 3.7 Relative voltage drop
JB/T 6747 -1993
The ratio of the voltage drop △U. to the test voltage U. Usually expressed as a percentage. 3.8 Voltage overshoot
The difference between the two when the actual average voltage is higher than the test voltage (Figure 2). 3.9 Relative voltage overshoot
The ratio of the voltage overshoot to the test voltage U. Usually expressed as a percentage. The reference pollution displacement
is used to characterize the pollution displacement value used in the unit test. This pollution displacement is the equivalent salt density in this standard. 3.11 Specified pollution displacement
The reference pollution displacement that the insulator passes the tolerance test when tested in accordance with the provisions of Articles 9 and 10 at the specified test voltage. 3.12 Maximum pollution displacement
The highest pollution displacement that the insulator passes the tolerance test when tested in accordance with the provisions of Article 11.1 at the specified test voltage. 3.13 Withstand voltage
The test voltage value at which the insulator passes the withstand test when tested in accordance with the provisions of Articles 9 and 10 under the specified pollution migration. 3.14 Maximum withstand voltage
The highest test voltage value at which the insulator passes the withstand test when tested in accordance with the provisions of Article 11.2 under the specified pollution migration. 3.1550% withstand voltage
The unit test voltage value with a 50% withstand probability when the insulator is tested in accordance with the provisions of Article 11.3 under the specified pollution migration. 4 General provisions of the test
Test power supply
During the test, the insulator shall be continuously pressurized under a test voltage of a specified polarity. Under a resistive load of 100mA, the voltage ripple factor shall not be greater than 3%. During the withstand process of the unit test, the relative voltage drop shall not be greater than 10%; the relative voltage overshoot shall be less than 10%. However, if the relative voltage overshoot flashes between 5% and 10, the unit test is invalid. 4.2 High-voltage measurement
High-voltage measurement shall comply with the relevant provisions of GB311.2 and 311.4, and the upper frequency limit of the measurement system shall not be less than 1kHz. 4.3 Mist
Use steam mist to wet the dirt layer. The concentration and flow rate of the mist shall be such that the conductivity of the dirt layer of the test sample reaches the maximum value within 20 to 50 minutes. The temperature of the mist chamber shall not be higher than 40℃. When the temperature reaches the maximum value, the temperature difference along the length of the test sample string shall not be greater than 1K/m, and the temperature difference of the test sample string before and after the test shall not be greater than 15K. The mist around the test sample shall be evenly distributed so that the moisture state of each part of the test sample is basically alternating. The steam input rate per cubic meter of the mist chamber volume shall be 0.10±0.05kg/h. 5 Preparation of the pollution transfer
5.1 Composition of the pollution transfer liquid
The pollution transfer liquid is composed of kaolin (2# or above Suzhou is recommended) or diatomaceous earth, water and an appropriate amount of salt (NaCl). Kaolin is recommended as the ash material.
In order to achieve the reference pollution transfer of the test sample (±15%), the test insulator can be pre-stained experimentally to determine the appropriate value of the volume conductivity of the pollution transfer liquid to be prepared. The required volume conductivity can be achieved by adjusting the salt plate in the pollution transfer reducer. Table 1 gives the reference values ​​of the corresponding relationship between the volume conductivity of the insulator pollution transfer liquid and the salt density of the test sample. These values ​​are obtained on standard disc-shaped suspension insulators in a naturally dry state and vertically stained. The volume conductivity values ​​of other types of insulation pollution transfer liquids need to be adjusted. 3
Salt density S
Characteristics of ash materials
JB/T6747-1993
Reference values ​​of bulk conductivity of kaolin contaminated pipette and sample density Volume conductivity
The characteristic values ​​of kaolin required for preparing contaminated pipette shall comply with the provisions of Table 2. Table 2 Properties of kaolin for preparing contaminated pipette Quantity
Sample preparation
Particle size (cumulative distribution)
Scrub the sample carefully with a mixture of water and kaolin or diatomaceous earth to remove all traces of dirt and grease, and then rinse with water. If a large area of ​​water film forms on the surface, it indicates that it is sufficiently clean. After cleaning, the cleaned sample should not be touched by hand. Then place it in the sample preparation room. Before contamination, the sample only needs to be rinsed once more. 6.2 Contamination
The volume conductivity of the water used to prepare the contamination solution should not be greater than 0.001S/m, and the dust density on the surface of the test sample should be 0.5mg/cm*. The sample can be contaminated by any of the following methods. When performing porcelain dyeing or spraying, the same batch of test samples should maintain the same and uniform insulation surface state before contamination. The same external environment and conditions should be maintained during the contamination process. For the inspection of contamination uniformity, see Appendix A. 6.2.1 Pouring method
Install the clean and dry insulator horizontally on the contamination machine. The rotation speed is generally 60/min. Pour the prepared and stirred contamination solution onto the rotating insulator so that it evenly covers the insulating surface of the insulator. Stop the rotation when the contaminant on the insulator no longer flows.
6.2.2 Spraying method
Use a spray gun to spray the pollutant onto the insulating surface of the test piece, so that the insulating surface of the test piece is evenly covered with a layer of pollutants. 6.2.3 Quantitative coating method
Calculate the amount of salt (NaCl) and ash materials required for each test piece based on the salt density, ash density and the insulating surface area of ​​the insulator. Weigh the salt with a balance with a minimum graduation value of 0.0001g, then add an appropriate amount of water to mix evenly, and evenly coat it all on the insulating surface of the test piece.
Selection and determination of insulator pollution transfer
The pollution transfer of the insulator is expressed by salt density. 7.1 Salt density of the test piece
The salt density of the test piece should be selected from the series in Table 1. JB/T6747-1993
7.2 Determination of salt density
Take an insulator (or part thereof) that is exactly the same as the insulator to be tested and contaminated in the same way. Carefully clean the dirt on the surface of the insulation and collect it carefully. Be careful not to clean the material on the metal accessories or adhesive materials. Dissolve the collected dirt in a certain amount of distilled water, stir evenly, and measure its conductivity (s/m) and solution temperature (). Calculate the salt density using formulas (1) to (3).
20[1-b(—20)
Where, -- solution temperature degree, ;
Volume conductivity at -0℃, s/m;
Volume conductivity at -20C, s/m: b——temperature correction coefficient.
The relationship between temperature and coefficient b is shown in Table 3.
Table 3 Relationship between solution temperature and b
Solution temperature
When the temperature is between 5 and 30℃, the coefficient b can be obtained by interpolation. When 0r is in the range of 0.004~0.4s/m, the salinity Sa (kg/m\) S, can be obtained by formula (2): =(5. 7 · 0r)1-03
Salt density S (mg/cm*) is obtained by formula (3)
S,=S,.V/A
Where: V is the volume of the dirty liquid, cm\; A is the surface area to be cleaned, cm\.
The determination of ash density
is carried out in accordance with the provisions of Article 7.2 of GB4585.2. The test sample is installed
Insulators are generally installed vertically in the fog chamber, or installed in the way of insulators. Special installation methods are agreed upon by the supply and demand parties. Insulators must be installed with all the metals they have during operation. Accessories (such as voltage-grading rings, wire clamps, etc.). Note: When conducting the pollution migration performance test of short-circuit insulators, the installation method shall be carried out in accordance with the provisions of the product standard. (1) The distance between the insulator and any grounding body (except for the insulator support) shall not be less than 0.5m for every 100kV test voltage, but at least not less than 1.5m. Test procedure Install the polluted insulator prepared in accordance with Article 6 in the fog chamber in accordance with Article 8. At the beginning of the test, the difference between the overflow of the test piece and the ambient temperature of the fog chamber should not be greater than 5K. JB/T 6747-1993
Apply the test voltage, and the test voltage shall be maintained until the test product flashes or the leakage current gradually decreases and flashover is impossible. The duration is detailed in Appendix B.
When the test voltage is applied, start the generator, and during the entire test period, input a continuous and stable steam into the fog chamber, with an input rate of 0.1±0.05kg/(h·m*). ​​The lower part of the fog generator should be as close to the ground as possible, and its nozzle should not be directly aimed at the test product itself, and should be more than 1m away from the test product, so that the fog around the test product is uniform. The dirt layer on the insulating surface of the test product is only allowed to be used once. After the unit test is completed, the steam in the fog chamber should be discharged, and after the fog chamber reaches thermal equilibrium with the outside air, it should be re-pressurized and fogged for the next unit test.
10 Acceptance criteria for withstand test
Under the specified test voltage and specified pollution migration, three tests are carried out according to the procedure of Article 9 without flashover, and the insulator passes the withstand test. If only one flashover occurs, a fourth test shall be conducted. If no flashover occurs, the test is passed. 11 Determination of withstand characteristics of insulators
In addition to being determined by the specified withstand pollution transfer degree at the specified test voltage, the withstand characteristics of insulators can also be expressed by the maximum withstand pollution transfer degree at a given test voltage, or by the maximum withstand voltage at a given reference pollution transfer degree. The evaluation process is as follows. Maximum withstand pollution transfer degree
Insulators shall be subjected to a series of tests at a certain voltage according to the pollution transfer degree levels listed in Table 1. The tests shall be carried out in accordance with the procedures of Article 9 and may be carried out in any order, provided that:
. If flashovers are achieved twice at any level of pollution transfer degree, it is not necessary to conduct tests at the same or higher level of pollution transfer degree. If withstand is achieved three times at any level of pollution transfer degree, it is not necessary to conduct tests at the same or lower level of pollution transfer degree. If three withstand tests (at any pollution degree) are passed and two flashovers occur at a higher pollution degree, this pollution degree is called the maximum withstand pollution degree under a certain test voltage.
11.2 Maximum withstand voltage
Insulators are subjected to a series of tests at a certain pollution degree according to the procedure of Article 9. Each test shall take the expected maximum withstand voltage as the starting voltage, with a voltage step difference of about 5%. The tests may be carried out in any order, as long as: a. If flashovers are achieved twice at any voltage level, it is not necessary to test at the same or higher voltage level; b. If the withstand is achieved three times at any voltage level, it is not necessary to test at the same or lower voltage level. If three withstand tests (at any voltage level) are passed and two flashovers occur at a higher voltage level, this voltage is called the maximum withstand voltage at a certain pollution degree.
11.350% withstand voltage
Insulators shall be subjected to at least 10 valid tests at a given reference pollution degree. The test shall be carried out according to the procedure of Article 9, and the value of the test voltage applied each time shall be changed by the step-up and step-down method. The voltage step difference shall not be greater than 10% of the expected 50% withstand voltage. The first test value that shows a different test result from the next test shall be taken as the first "valid" test value. The 50% withstand voltage shall be determined by combining this and at least 9 subsequent valid test values. The 50% withstand voltage shall be calculated according to formula (4): where U.--a certain applied voltage value; n;--the number of tests conducted under voltage U; N--the number of valid tests. (4) JB/T6747-1993 Appendix A Measurement of the conductivity of the pollution layer for checking the uniformity of pollution (supplement) The device for measuring the conductivity (K) of the pollution layer on the surface of the insulator mainly consists of a probe and an instrument. The following probe and instrument are used as examples.
Probe (Fig. A1)
Fig. A1Arrangement of probe electrodes
Two spherical stainless steel electrodes, 5 mm in diameter, 14 mm apart from each other. The two balls extend from the probe and are pressed against the surface of the insulator by means of a handle, and a constant surface pressure is obtained by means of a spring mechanism which generates a force of about .9 N. Instrument (Fig. A2)
Measuring instrument
Measuring range selector
Measuring deviceCharging rate 50 μAInternal resistance 1.5 kmFig. A2Circuit of measuring instrument
JB/T 6747 - 1993
A current is passed between the two electrodes and the surface between them by a 6.8 V Zener diode regulated power supply. The instrument with a full deflection range of 50 μA is protected by a diode connected in parallel.
For a film with a 50 μS layer conductivity, the resistance between the electrodes is assumed to be 32.7 kN; the corresponding values ​​for 100 μS and 500 μS layer conductivities are expected to be 16.35 kN and 3.27 kN. Each of these resistors is connected to a plug-in test cell in parallel with the electrodes. The measuring range selector switch is used to select the full dial deflection for each measuring range. The above measurements of the layer conductivity should be made at different points on the insulator surface. Polarization effects can be noted by pressing the instrument button briefly.
The uniformity of the layer is considered to be acceptable when the difference between the individual measured values ​​and the average value of the measured values, expressed as a percentage of the average value, does not exceed ± 30%.
Appendix B
Duration of Withstand TestwwW.bzxz.Net
(Supplement)
Present experience shows that the risk of flashover is negligible when the test sample withstands the test voltage for more than 100 min after fogging.However, the degree of flashover danger can also be directly determined by measuring the leakage current value flowing through the test piece during the test. The leakage current first reaches a peak value, and then its value gradually decreases due to the cleaning of the pollution layer. Measure the leakage current. If there is no flashover after 30 minutes from the occurrence of local arcing, and the leakage current gradually decreases, the risk of flashover can be ignored. When it is determined that flashover is impossible by measuring the leakage current or other technical means, the test can be terminated and judged as tolerance passed. Additional notes:
This standard was proposed by the National Technical Committee for Insulator Standardization. This standard is under the jurisdiction of the Xi'an Electric Ceramics Research Institute, and the Xi'an Electric Ceramics Research Institute is entrusted to interpret it. This standard was drafted by the Xi'an Electric Ceramics Research Institute. The main drafters of this standard are Song Zetian and Luo Yan. 8
People's Republic of China
Mechanical Industry Standards
DC System
Test Method for Artificial Pollution Migration of High-voltage Insulators
JB/T 6747 -1993
Solid Layer Method
Published by the Mechanical Science Research Institute
Printed by the Mechanical Science Research Institute
(No. 2, Shouti South Road, Beijing
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