JB/T 3140-1982 Corona protection standard for high voltage motors used in high altitude areas JB/T3140-1982 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China Technical Requirements for Corona Protection of High-voltage Motors in High-altitude Areas 1 Subject Content and Scope of Application
JB8439-1996
Replaces JB3140-82
This standard specifies the technical requirements, test methods and inspection rules for corona protection of AC high-voltage motors in high-altitude areas. This standard applies to motors with an operating altitude of 1km to 5km, a rated working voltage of 6kV and above, and windings and cores in contact with the ambient atmosphere.
3kV motors with corona protection requirements should also be used as a reference. 2 Reference standards
GB755 Basic technical requirements for rotating electrical machines
GB7894 Basic technical conditions for hydroelectric generators GB/T14597 Climate and environmental conditions for electrical products at different altitudes JB/T7573 General technical conditions for electrical products under plateau environmental conditions 3 Terms
3.1 Corona
The gas around the bare or insulated conductor undergoes a localized free glow discharge under the action of an electric field. 3.2 Corona starting voltage
Under specified conditions, the minimum voltage value applied to the test product to start generating continuous corona. 4 Technical requirements
4.1 Anti-corona measures should be taken for the motor to improve its anti-corona performance. 4.2 The corona inception voltage of the motor wire rod (or coil) should not be lower than the value obtained by the following formula: 1-KHs
Uws=1. 5Ur
INi-KHA
Wherein: U-
The corona inception voltage of a wire rod (or coil), kV; Un—Rated voltage of the motor, kV;
K---The decrease rate of corona inception voltage with increasing altitude, take K equal to 0.1, km-1; Hs-—Altitude of the motor test site, kmHa—Altitude of the motor installation site, km; 4.3 The corona inception voltage of the motor as a whole should not be lower than the value obtained by the following formula: 1-KHs
Us=1. 3U-KHA
Wherein: Uis—Corona inception voltage of the motor, kV; U——Rated phase voltage of the motor, kV.
4.4 Other requirements not specified in this standard shall comply with the professional technical regulations of this type of motor. Approved by the Ministry of Machinery Industry on September 3, 1996
Implemented on January 1, 1997Www.bzxZ.net
5 Test method
5.1 Determination of corona
JE8439-1996
Use visual observation method under dark environment conditions. 5.2 Test safety
Corona test is carried out under safe protection conditions. 5.3 Test voltage
The test voltage should be an AC voltage with a frequency of 45 to 55 Hz, its waveform should be close to sine, the two half waves should be exactly the same, and the ratio of the peak value to the root mean square (effective) value is equal to ~2±0.07.5.4 Test product
5.4.1 The tested wire rod (or coil) and motor should be clean and dry. 5.4.2 The test bar (or coil) shall be used as the grounding electrode in the corresponding core section by wrapping aluminum foil, etc. The electrode and the low-resistance layer of the bar (or coil) shall be in good contact!
5.4.3 The test bar (or coil) shall be placed horizontally on the insulating bracket, and the test circuit shall not produce tip discharge. 5.5 Test Procedure
5.5.1 The tester shall adapt his vision to the dark environment for 5 minutes when entering the dark room or dark place. 5.5.2 During the test, there shall be two or more experienced testers to observe the test product comprehensively at the same time, and the observation results shall be confirmed by two people.
5.5.3 The voltage applied during the test shall not exceed half of the corona starting voltage value specified in 4.2 or 4.3, and then increase evenly to the full value. The time for the voltage to increase from half value to full value shall not be less than 108. The observation and confirmation of the test results under the full value voltage shall not exceed 1 minute.
After the test observation is completed, the voltage shall be uniformly reduced to below half the test voltage, and then quickly reduced to zero. After disconnecting the power supply, the test sample shall be discharged to the ground.
6 Inspection Rules
6.1 The corona test of motor wire rods (or coils) shall be conducted by sampling. The number of samples to be sampled shall not be less than 10% of each unit (or each batch). The test results shall be qualified if they meet the provisions of Article 4.2. If any unqualified samples are found, double the number of samples shall be sampled for testing. If there are still unqualified samples, all the wire rods (or coils) in this batch shall be tested. At the same time, the reasons shall be analyzed and measures shall be taken to improve the anti-corona performance of the product. 6.2 The motor shall be subjected to corona test before leaving the factory. If the observation of the corona test is limited due to structural influence after the motor is assembled, it is allowed to use the stator of the finished machine instead of the whole machine for testing. For motors that must be assembled at the installation site, the test site can be selected at the installation site. The test results shall be qualified if they meet the provisions of Article 4.3. 370
JB8439—1996
Appendix A
Relationship between altitude, average air pressure and maximum temperature in high altitude areas of my country (supplement)
Relationship between altitude, average air pressure and maximum temperature is shown in Table A1. Table A1
Altitude, km
Average air pressure, kPa
Maximum temperature,
Table A1 complies with the provisions of GB/T14597 and JB/T7573. Appendix B
Corona prevention measures for high voltage motors
(supplement)
B1 Anti-corona treatment is applied to stator bars (or coils). B2 Low-resistance anti-corona paint is sprayed inside the stator slots. 3.0
B3 The size of the stator bar (or coil) and the slot should be closely matched to ensure reliable and stable contact. If the single-sided gap is greater than 0.3mm and the length is greater than or equal to 300mm, epoxy semiconductor material should be used to plug it. B4 The pads in the stator slot and the plugging corrugated plates should be made of anti-corona materials. B5 The ends of the stator windings should be supported and tied firmly; the gaps between the fixings should be filled with insulating materials such as epoxy resin. B6 The stator slot wedges should be pressed tightly.
Additional notes:
This standard was proposed and managed by the Kunming Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Kunming Electric Science Research Institute of the Ministry of Machinery Industry. The main drafters of this standard: Yang Xingzhou, Sui Yinde, Sun Angen, Cai Beifeng, Huang Junkang. 371
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