Vacuum pump rate (L/s): 15
Ultimate vacuum (Pa): ≤6*10-2
Vacuum pumping time (s): (2)30L, (4)60L, (12)180L, (20)300L, (40)600L, (80)1200L
Dimensions: 90cm×65cm×100cm (L×W×H)
Weight: approximately 250Kg
Working voltage: 380~460V 50Hz AC
Noise level: <78dB(A)
Main Components of SF6 Gas Vacuum Pumping Device1. Vacuum pump * Rated rate 54m3/h, vacuum degree <0.06Pa 1
2. Pipeline Length 5m/3m 1
3. Ball valve. Solenoid valve DDC vacuum solenoid valve 2
4. Vacuum gauge McLeod vacuum gauge 1
5. Connection plug Optional various types of electrical equipment interfaces 1
SF6 gas has many advantages, especially in insulation performance. Long-term high-voltage operation of SF6 gas will decompose toxic and harmful products, which not only reduces the electrical performance of SF6, but also poses a threat to human health if directly discharged into the atmosphere. Even a very small amount of some decomposition products can be fatal. However, SF6 series electrical equipment has high requirements for processing technology and materials, resulting in high product prices; high requirements for preventing SF6 gas leakage, and a series of auxiliary gas replenishment measures are needed; it cannot completely rule out the possibility of explosion; the low-chlorine compounds generated after arc combustion are highly toxic, threatening personal safety and easily causing environmental pollution.
For example: Decomposition of SF6 gas in arc and its reaction with oxygen:
2SF6 + O2 →2SOF2 + 8F (thionyl fluoride)
2SF6 + O2 →2SOF4 + 4F (sulfuryl tetrafluoride)
SF6 →SF4 + 2F (sulfur tetrafluoride)
SF6 →S + 6F (sulfur)
2SOF4 + O2 →2SO2F2 + 4F (sulfuryl fluoride)
The decomposition products of SF6 gas in electrical equipment react chemically with moisture inside to generate certain toxic products
For example: Secondary reactions of SF6 gas decomposition products with water:
SF4 + H2O →SOF2 + 2HF (hydrofluoric acid)
SOF4 + H2O →SO2F2 + 2HF (hydrofluoric acid)
SOF2 + H2O → SO2 + 2HF (sulfur dioxide)
SO2F2 + 2H2O → H2SO4 + 2HF (sulfuric acid
SF6 gas and its decomposition products in electrical equipment react with electrodes (Cu-W alloy) and metal materials (Al, Cu) to generate certain toxic products
For example: Reactions of SF6 gas and decomposition products with electrodes or other materials:
3SF6 + W → WF6 (gaseous) + 3SF4
3F + Al →AlF3 (solid powder)
3SOF2 + Al2O3 →2AlF3 (solid powder) + 3SO2
SF6 + Cu →CuF2 (solid powder) + SF6
4SF6 + W + Cu →2S2F2 (gaseous) + 3WF6 (gaseous) + CuF2 (solid powder)
SF6 gas and its decomposition products in electrical equipment react with insulating materials to generate certain toxic products.
For example, with epoxy phenolic glass cloth laminate (rod, tube) and other insulating parts containing silicon components; or with epoxy resin castings, moldings filled with quartz sand or glass, as well as porcelain insulators, silicone rubber, silicone grease, etc., chemical reactions occur, generating products such as SiF4, Si(CH3)2F2, etc.
With the promotion of new technologies and the application of new equipment and materials, SF6 equipment has been widely used in power systems due to its advantages of safety, reliability, easy maintenance, and long service life. It plays an important role in the safe, economic, and stable operation of power systems. However, SF6 equipment used is produced by multiple manufacturers, with various basic structures and operating mechanisms. SF6 equipment of different manufacturers, models, and voltage levels also have different standards and varying manufacturing process levels, which brings difficulties to installation, operation, and maintenance personnel in the application and maintenance of SF6 equipment, thereby affecting construction and maintenance quality, and even leading to failures due to gas leakage, which has a certain impact on the safe operation of power systems. Therefore, the management of SF6 gas in SF6 equipment should be given attention.
1 Operation and Maintenance of SF6 Gas
1.1 Regular patrol inspection. Duty personnel should inspect SF6 electrical equipment daily using an infrared dual-wave leak detector. If leakage is found, it can be detected whether the leakage content exceeds the standard, and it should be reported immediately for timely handling.
1.2 Patrol inspection of explosion-proof membrane. For GIS equipment equipped with explosion-proof membranes, patrol inspections should be conducted at fixed times daily, but personnel should not stay near the explosion-proof membrane. If any abnormality is found, report immediately. If the explosion-proof membrane is damaged, power should be cut off for handling. The explosion-proof membrane should be wiped clean with gasoline or acetone.
1.3 Regular calibration of alarm devices. The pressure setting value should be verified annually, checking whether the contacts and alarm are intact, and whether the connections of each wire are loose, etc.
2 Moisture Measurement and Treatment of SF6 Gas
2.1 Measurement of moisture content. Use a moisture meter to measure the moisture content of SF6 gas. Generally, measure once every 3 months, and after stabilization, reduce to once a year.When significant changes in moisture content are found, re-measurement should be conducted and the cause analyzed. The moisture content of SF6 gas in circuit breaker chambers during operation shall not exceed 3X10-4.
2.2 Treatment when moisture content exceeds the standard. If the measured moisture content of SF6 gas exceeds the maximum allowable value, an SF6 gas treatment vehicle can be used to dry and filter the SF6 gas. For gas chambers with high moisture content, vacuum should be applied, dry nitrogen should be used for displacement, and adsorbents should be used to absorb moisture.
