Common faults and preventive measures of sulfur he

2022-10-14
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Common faults and preventive measures of SF6 circuit breaker in substation

SF6 circuit breaker is one of the main electrical equipment in substation. During the installation and operation of SF6 circuit breaker, due to the installation environment, operation methods and other reasons, it may lead to the disconnection of SF6 and various potential safety accidents with different properties in the medium and long-term slurry price support circuit breaker. In order to ensure the arc extinguishing effect of sulfur hexafluoride circuit breaker in electrical operation and improve the safe and reliable operation of electricity, this paper adopts the technology of "particle fireproof isolation film". Based on the defects and faults of sulfur hexafluoride circuit breaker in substation operation, this paper analyzes various faults of sulfur hexafluoride circuit breaker

fault analysis

sulfur hexafluoride circuit breaker mainly uses sulfur hexafluoride gas as the medium for arc extinguishing and insulation. However, only in the purer sulfur hexafluoride gas can it have high insulation performance and good arc extinguishing ability. If there is water intrusion in the gas, it will usually lead to the reduction of electrical strength and the chemical reaction between water and arc products, such as sulfuric acid Hydrofluoric acid or other toxic chemical substances, after these substances are generated, when the inspectors and repairmen approach, it is likely to endanger their life safety. In addition, these toxic and harmful substances will also cause serious corrosion to the metal materials and insulating materials in the circuit breaker, resulting in serious insulation deterioration and equipment explosion

solid impurities will affect the circuit breaker. Under normal circumstances, there are more or less free conductive impurities in the arc extinguishing chamber of sulfur hexafluoride circuit breaker. Sulfur hexafluoride gas containing impurities usually reduces its breakdown voltage to 10% of the breakdown voltage of pure sulfur hexafluoride gas, and the breakdown voltage containing impurities is also closely related to the size, location, material, shape and operating characteristics of impurities, Impurities will reduce the breakdown voltage of the gas gap between the shell and the charged part, and even be broken down seriously; Impurities will also cause the arc of the circuit breaker to re ignite, resulting in the failure of arc extinguishing

SF6 gas leakage is also an important factor affecting the safe operation of circuit breakers. It is an important topic to find out the causes of SF6 gas leakage and formulate corresponding countermeasures to minimize SF6 gas leakage

preventive measures

strengthen the control of moisture in sulfur hexafluoride gas. First, control the water content of the gas in the SF6 circuit breaker. Before filling the new gas, the acceptance inspection shall be carried out according to the corresponding quality standards, and the purity of the new gas shall be greater than 99.8%. In addition, water, air, mineral oil and other technical indicators must meet the requirements of national standards

secondly, we should try to avoid bringing in moisture due to improper operation or being limited by the inflation device. Before inflation, check the pressure of the new gas cylinder to see whether it meets the factory requirements. Then, wash all pipelines, and use an electric blower to heat and dehumidify the joints. When inflating, unscrew the cylinder control valve first, flush the connecting pipe with sulfur hexafluoride gas, and then connect it with the circuit breaker to prevent moisture from entering the circuit breaker. After inflation, the air pressure in the gas chamber of SF6 circuit breaker shall be higher than the actual required value as far as possible. Finally, the porcelain bushing and coil of SF6 circuit breaker shall be checked, and the body of the experimental machine shall be constructed with standard steel to keep the porcelain bushing intact and the coil sealed well, so as to prevent the circuit breaker from being damp or damaged during installation

control measures for solid impurities. When selecting SF6 circuit breaker, the installation and use unit shall select the manufacturer with complete quality assurance system and qualified product quality, so as to ensure that the impurity content in the circuit breaker meets the relevant standards. In addition, in the process of installation and use, the alarm circuit of sulfur hexafluoride circuit breaker should be checked regularly, the inspection of the leakage prone position of the circuit breaker should be strengthened, and the leakage of sulfur hexafluoride circuit breaker should be checked regularly

find the leakage position and treatment method. Patrol personnel should regularly check the recent gas filling records. If the gas density decreases at a rate greater than 0.01 MPA/year, they must use a leak detector to detect and replace seals and other damaged parts. If the leakage is fast, inflate it to the rated pressure, check the pressure gauge, and use a leak detector to find the leakage point of the pipe joint; In addition, the leakage point can be found by wrapping phase by phase and sealing parts one by one

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