This standard specifies the method for determining the power frequency breakdown voltage of the dielectric strength of cable paper. This standard is applicable to the breakdown strength of unimpregnated power cables or similar fiber insulation papers under power frequency voltage. GB/T 3333-1999 Power frequency breakdown voltage test method for cable paper GB/T3333-1999 Standard download decompression password: www.bzxz.net

ICS85.060
National Standard of the People's Republic of China
GB/T3333--1999
neqIEc554-2:1977
Test Method for Power Frequency Breakdown Voltage of Cable Paper
Cable paper--Determination of electrical strength that power frequency
Published on August 12, 1999
Implemented on February 1, 2000
Published by the State Administration of Quality and Technical Supervision
GB/T3333-—1999
This standard adopts IEC554-21977 "Specification for Electrical Fiber Paper" in a non-equivalent manner, and is a revision of GB/T3333-1982 "Test Method for Power Frequency Breakdown Voltage of Cable Paper".
This standard shall replace GB/T3333-1982 from the date of implementation. This standard is proposed by the State Bureau of Light Industry.
This standard is under the jurisdiction of the National Technical Committee for Standardization of Paper Industry. The drafting unit of this standard: China Pulp and Paper Industry Research Institute. The main drafters of this standard: He Suoqin, Chen Shuo, Zhang Shaoling, Han Xiuzhen, Zhang Qing. 1 Scope
National Standard of the People's Republic of ChinaWww.bzxZ.net
Test method for power frequency breakdown voltage of cable paper
Cable paper Determination of electrical strength at power frequency
This standard specifies the method for determining the dielectric strength of cable paper - power frequency breakdown voltage. GB/T3333—1999
neqIEC554-2:1977
Replaces GB/T3333—1982
This standard is applicable to the test of the breakdown strength of unimpregnated power cables or similar fiber insulation papers under power frequency voltage. 2 Definitions
This standard adopts the following definitions.
2.1 Breakdown voltage breakdownvoltage
Under the specified test conditions, the power frequency voltage is applied to the cable paper by the method of continuous and uniform voltage increase, so that the voltage value when the paper sample breaks down.
2.2 Electric strength electricstrength
Under the specified test conditions, the voltage value at which the cable paper sample breaks down is divided by the average thickness of the paper sample between the two electrodes where the voltage is applied. 3 Test equipment, electrodes and sample processing equipment 3.1 Test equipment
The basic circuit is shown in Figure 1 and should meet the following basic requirements. 3.1.1 The capacity of the high-voltage test transformer should ensure that the secondary rated current is not less than 0.04A. 2 The power frequency power supply should be a 50Hz sine wave, and the crest factor of the test transformer output voltage is 1.31~1.51. 3.1.2
3.1.3 The protection resistance value is calculated as (0.2~0.5)α per volt of voltage, that is, (0.2~0.5)α/V. 3.1.4 The voltage regulator should be able to adjust the voltage evenly, and its capacity should be the same as that of the test transformer. 3.1.5 The overcurrent relay should have sufficient sensitivity to ensure that the power supply is cut off within 0.1s when the sample breaks down. The operating current value should be selected appropriately to avoid non-operation after breakdown or false operation when there is no breakdown. 3.1.6 Voltage measurement
On the high voltage side, use an electrometer with an accuracy of not less than 1.5. On the low voltage side, use a voltmeter with an accuracy of not less than 0.5, and the measurement error should not exceed ±4%.
Approved by the State Administration of Quality and Technical Supervision on August 12, 1999, and implemented on February 1, 2000
3.2 Electrodes
GB/T3333-1999
T.-voltage regulator; T2-test transformer; R-protective resistor; Cx-sample; V-voltmeter; F-fuse; L-indicator light; S, Sz-buttons; J-overcurrent relay coil; Jz-contactor; J'-overcurrent relay contact; J'2-contactor contact; K-power switch Figure 1 Schematic diagram of test equipment
Electrodes are made of brass. The finish of the working surface shall not be less than R,6.3μm. The electrodes shall be ground once after every 200 breakdown tests. The electrode size and configuration are shown in Figure 2.
3.3 Sample processing equipment
1-upper electrode; 2-lower electrode; 3-sample Figure 2 Electrode size and configuration diagram
Electrothermal constant temperature oven with heating temperature up to 150C. In order to conduct breakdown test, the oven should be equipped with high voltage and grounding leads. 4 Sample preparation
4.1 For cable paper with thickness less than or equal to 0.060mm, the sample consists of two layers of paper; for cable paper with thickness greater than 0.060mm, the sample consists of a single layer of paper.
4.2 The sample size should be large enough, and its width should not be less than twice the diameter of the lower electrode to prevent slippage between electrodes. The sample length depends on the number of tests required to be met on one sample. 4.3 The sample surface should not have defects such as folds, wrinkles, light transmission points, particles, pinholes, etc. 5 Test steps
5.1 Sample processing and test conditions
The sample is dried at a temperature of (105±5)℃ for 2h. The dried sample should be kept at a temperature of (90 ± 2) ° C for 30 minutes, and then cooled to room temperature before the breakdown test is performed. However, it must be ensured that the sample does not absorb moisture and significantly affect the dielectric strength of the sample. When there is any objection, the test at (90 ± 2
2) ° C shall be used as the benchmark test.
5.2 Voltage boosting method and voltage boosting speed
GB/T3333-1999
Use a continuous and uniform voltage boosting method, and the voltage rises from zero to the breakdown voltage in a time of (10 to 20) s. 5.3 Electrode pressure
It is the electrode's own weight, and the paper surface is pressed flat. 5.4 Judgment of breakdown
The sample is considered to be broken down if there are small holes, burns, etc. along the direction and position of the applied voltage. If the traces are not obvious, it can be judged by repeatedly applying the test voltage at the original position. Take the first breakdown voltage value when there is no abnormality in the equipment. 5.5 Number of tests
Nine effective breakdown tests shall be conducted. If the breakdown occurs at the edge of the electrode, the test shall be invalid and the number of effective breakdown tests shall not be counted. 6 Test results
The breakdown voltage is in volts. For a specimen consisting of two layers of paper, the breakdown voltage of the paper shall be half of the breakdown voltage of the specimen. The middle value of the obtained test values ​​shall be taken as the test result, and the minimum value shall be reported. Test record
The test record shall include the following:
a) Model, name, specification, manufacturer and date of manufacture of the tested material; b) Sample processing parameters: temperature, time, relative temperature and test conditions; c) Number of paper layers of the sample;
d) Name, model and specification of the test equipment; e) Measurement data and test results;
f) Test date and tester;
g) Any deviation from this standard.
People's Republic of China
National Standard
Test method for power frequency breakdown voltage of cable paper
GB/T 3333—1999
Published by China Standards Press
No. 16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 68522112
Printed by Qinhuangdao Printing Factory of China Standards Press Distributed by Beijing Distribution Office of Xinhua Bookstore Sold by Xinhua Bookstores in all regions Copyright is exclusive and no reproduction is allowed
Format 880×12301/16
5 printing sheets 1/2 Number of words 7,000 words
First edition in December 1999
First printing in December 1999
Print run 1-1000
Book number: 155066·1-16269
Price 6.00 yuan
Heading 392-07
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