JB/T 8639-1997 Guidelines for temperature rise test of oil-immersed power transformers with analysis of dissolved gases in oil JB/T8639-1997 Standard download decompression password: www.bzxz.net

Article C4 in Appendix C of JB/T86391997
GB1094.2-1996 "Power Transformer Part 2 Temperature Rise" requires that during the temperature rise test, the gas dissolved in the oil be subjected to chromatographic analysis to determine whether the product has local overheating. The purpose of formulating this standard is to formulate a more reasonable and unified recommended test method and judgment criteria for evaluating test results for the transformer industry. This standard is formulated on the basis of the judgment criteria of the international large power grid work report and the relevant contents of IEC567. The judgment criteria of the international large power grid work report have been verified to be effective after 198 tests in more than a dozen countries. This standard has been tested and verified in several large transformer factories in China.
This standard was proposed and managed by the Shenyang Transformer Research Institute of the Ministry of Machinery Industry. The drafting units of this standard are: Shenyang Transformer Research Institute, Baoding Tianwei Group Large Transformer Factory, Guangzhou High Voltage Electric Appliance Factory, Wuhan High Voltage Research Institute.
The main drafters of this standard are: Gao Changhong, Liu Yuxian, Liu Xingyuan, Wu Yihua. This standard was first issued in 1997.
1 Scope of application
Standard of the Machinery Industry of the People's Republic of China
Guidelines for temperature rise test of oil-immersed power transformers with dissolved gas analysis in oil
JB/T8639-1997
This standard specifies the temperature rise test method and requirements for oil-immersed power transformers with dissolved gas analysis in oil. This standard is applicable to the following oil-immersed power transformers: a) three-phase transformers with independent windings, rated capacity ≥120MVA; b) single-phase transformers with independent windings, rated capacity of each column ≥40MVA; c) equivalent rated capacity of three-phase autotransformers or single-phase equivalent rated capacity of each column, which are equivalent to the values ​​listed in a) and b) respectively; d) transformer rated capacity is less than the limit values ​​shown in a), b) or c), but its leakage flux or leakage magnetic field is greater than or equivalent to the above three cases.
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. GB1094.2--1996 Power transformers Part 2 Temperature rise (eqvIEC76-2:1993) GB1094.3—1985 Power transformers Part 3 Insulation levels and insulation tests (eqvIEC76-3:1980) GB/T6451--1995 Technical parameters and requirements for three-phase oil-immersed power transformers (neqDIN42500:1984) IEC567:1992 Guidelines for taking oil and gas samples from oil-filled electrical equipment and for analyzing free and dissolved gases 3 Temperature rise test
The status of the power transformer undergoing temperature rise test shall, in addition to complying with the provisions of GB1094.2, also meet the following conditions: a) If an insulation test is required before this test, the insulation test shall be qualified; b) If partial discharge measurement is also carried out, the discharge level shall not be greater than the value specified in GB1094.3. The temperature rise test shall be carried out in accordance with the relevant requirements of GB1094.2 and GB/T6451. The test shall be carried out at the maximum current tapping, and the duration of the temperature rise test with dissolved gas analysis in oil shall be at least 12 hours. For transformers with forced oil circulation (i.e., the oil flow circulation mode is ()F or ()D), the oil pump and fan shall have been running for at least 2 hours before the start of the temperature rise test, and shall not stop running until the last oil sample is drawn. 4 Oil sampling
4.1 General
The instruments and methods used for oil sampling shall comply with the provisions of Chapter 4 of IEC567. It is recommended that oil samples be drawn by full-time personnel who have received special training and can operate proficiently in accordance with IEC567 standards. Two samples of oil should be taken each time, one for test and one for backup.
Approved by the Ministry of Machinery Industry on September 25, 1997
Implemented on January 1, 1998
4.2 Sampling device
JB/T86391997
4.2.1 Airtight oil-resistant plastic or rubber tube is used to connect the equipment and the syringe. The connecting tube should be as short as possible and a three-way piston should be inserted into the tube.
4.2.2 Oil sample container
The container is a sealed glass syringe with a capacity of 50 or 100 mL, which is equipped with a piston or plug that can seal it. The airtightness of the syringe must be tested and qualified.
4.2.3 Transport container. The design of this container should ensure that the syringe is firmly fixed in place during transportation, but the plunger of the syringe should be allowed to move freely.
4.3 Sampling location
The oil sample taken should be representative of the state of all the oil in the transformer under test. The oil sample should be taken from the location where the oil can circulate freely. It is recommended to drain at least 2I of oil before each sampling. 4.4 Sampling location
The oil sample extraction in the temperature rise test is recommended to be carried out according to the following procedures: Initial oil sample: extracted just before the test begins; Intermediate oil sample: at least two oil samples are extracted at specified time intervals during the entire test period. Usually, the first oil sample is best extracted when the temperature has just reached stability; the time intervals for extracting the remaining oil samples should be even, but the last oil sample should be extracted within 1 to 2 hours before the end of the test.
The last oil sample is extracted about 2 hours after the end of the test. Note: It is recommended to extract a supplementary oil sample 24 hours after the end of the test. To estimate its slow diffusion effect. 4.5 Oil sample marking
Before the oil sample is sent to the test room, a label of appropriate size should be affixed, which should at least indicate the following: the factory serial number of the tested transformer;
the date and time of sampling; bzxz.net
the extraction location.
4.6 Storage of oil samples
The oil sample must be stored in a container wrapped in aluminum foil or in a light-proof sealed container to prevent oxidation caused by light. The oil sample extracted during the temperature rise test should be analyzed in the test room as soon as possible, and must be completed within 4 days at the latest. 5 Degassing
Degassing method
The commonly used degassing method is the dissolution equilibrium method (i.e., the mechanical oscillation method), which is characterized by simple operation, and the repeatability and reproducibility generally meet the requirements.
6 Analysis
The degassed gas is analyzed by gas chromatography. When determining the allowable change value of various gases during the temperature rise test, the "maximum analytical dispersion method" Sa should be used as the benchmark. This dispersion can be comprehensively estimated by the oil samples extracted at the same time and position, the variation characteristics of the oil samples themselves, the extraction process and analysis characteristics.
The "maximum analytical dispersion" can be expressed as a function of the minimum detectable value Sd and the amount of relevant dissolved gas in the oil before the test. If the initial amount of the relevant gas is represented by (X) (X is the chemical symbol of a certain gas), the maximum analytical dispersion of a certain gas can be expressed by the following formula:
Sa(X) = 0. 1(X), + 2Sd(X)
The minimum detectable values ​​of various gases can be obtained from Table 1. Table 2 lists the maximum values ​​of dissolved gases in the oil of new transformers before the overflow test for reference. New products usually do not exceed these limits. Allowable limit of gas growth rate in temperature rise test For the gas growth rate in temperature rise test, the following discriminant group and Ⅱ respectively specify their four limit expressions. In the formula, represents the duration of temperature rise test (h); the unit of gas content is u/. Minimum detectable value of gas in oil
Sd(μL/L)
X(μL/L)
7.1 Discriminant group 1
Carbon oxide
·Carbon oxide
Carbon dioxide
Maximum value of dissolved gas in new transformer oil
Carbon dioxide
1) (C,H2)2 --(C,H2),
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