What is the annual leakage rate of sulfur hexafluoride high pressure equipment?- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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What is the annual leakage rate of sulfur hexafluoride high pressure equipment?

发布时间：2015-09-03 来源：ydlcb 浏览次数：33次

High voltage switch production plant to produce SF6 load switch and inflatable cabinet switching equipment, mainly to solve the following technical problems:

1, sealing problem: air leakage rate has always been the focus of manufacturers and users. The annual leakage rate of SF6 load switch and inflation cabinet is less than 1%/ year. The service life of the switch is generally about 30 years. Sealing should take into account the compression of sealing components, life, aging, reliability factors. When the SF6 gas pressure in the box drops to the atmospheric pressure, it seems that the internal and external pressure is equal, and the gas does not leak. However, from the perspective of penetration, the SF6 gas concentration in the box is obviously higher than that outside the cabinet, and the SF6 gas is still leaking out, whereas the air concentration outside the box is higher than that inside the box, and the air will enter the gap inside the box. Over time, the gas pressure in the box is still atmospheric pressure, but the gas composition changes. The percentage of SF6 gas is reduced, and when the SF6 proportion is reduced to 40%, the insulation performance may decline and lead to accidents, and the sealing problem must be paid attention to.

SF6 load switches generally use sealing rings to achieve gas dynamic and static sealing (such as ABB, SFG, Schneider SM6 switches); There are also very individual use of stainless steel welding and sealing ring combined sealing form (VEISF6 switch); C-GIS gas cabinet sealing methods include welding sealing, sealing ring sealing and metal bellows sealing. The welding seal is used to ensure the air tightness of the weld, and the general welding equipment and welding technology can not meet the requirements, at least with argon arc welding or laser welding equipment for welding (at present, there are several domestic welding robot production equipment introduced from abroad) to ensure the quality of welding.

There are two common SF6 gas leak detection methods: one is qualitative leak detection, that is, leak detection; The second is the quantitative leak detection, that is, the gas concentration in the sealed volume is measured after 24 hours of sealing to calculate the annual leak rate. In addition, it is necessary to consider the impact of environmental factors on sealing performance, such as whether the sealing performance meets the requirements under high or low temperature conditions.

Gas moisture content problem: SF6 gas moisture content is one of the main detection indicators of SF6 switch quality, and its size directly affects the insulation level of the switch. When the water content in SF6 gas is lower than the saturation value at this state temperature, the water is stored in SF6 gas in the gas state. The test shows that the insulation performance of SF6 switch is basically not affected at this time. If the moisture content of the gas exceeds the saturation value, part of the water vapor will condense on the surface of the solid insulation inside the switch, and then reduce the flashover voltage along the surface, and the arc extinguishing performance of the switch will also be affected. DL/T596-1996 "Preventive Test Procedures for Electric Power Equipment" stipulates that the water content of SF6 switch shall not exceed 150ppm after new operation and overhaul, and shall not exceed 300ppm during operation. New SF6 gas, first of all to check the gas itself moisture content, does not exceed the specified value (general moisture content of 15 ppm). The sealed box is put into an appropriate amount of dried adsorbent, which is mainly used to absorb water to ensure that the moisture content in the sealed box does not exceed the standard provisions. All parts in the sealed box (including the sealed box, transmission parts, contact blades, etc.) and standard parts should be baked strictly according to the baking temperature and baking time of each component, strictly control the moisture content of the parts themselves, and ensure the packaging time of the parts. When SF6 switchgear is vacuumed and inflated, high purity nitrogen or sulfur hexafluoride gas is used to clean the inflatable pipe, control the moisture content in the pipe, and standardize the production process of SF6 switchgear. 3, parts quality problems: parts quality is directly related to product quality.

SF6 load switch and inflatable cabinet are maintenance-free or less maintenance switchgear, once the parts in the sealed box have quality problems, it is very likely to be scrapped into the whole switchgear. To ensure the quality of parts, it is necessary to strictly control the materials, processing technology and inspection methods of parts, and its mechanical strength, electrical performance and other parameters meet the product requirements. More stringent inspection of the parts required to be loaded, and more stringent process control and process inspection control are required for the entire assembly process to ensure the correctness and consistency of the assembly. In particular, the transmission link and contact surface lubrication in the sealed box should be effective throughout the product life cycle, the contact pressure should be strictly controlled, and the resistance value of the main circuit of the switch should meet the technical requirements of the product during the life cycle. With the rapid development of social economy and the continuous growth of urban power load, the demand for power supply reliability is getting higher and higher, and high-performance ring network distribution, multi-loop distribution, switching and closing stations have become one of the irreplaceable important equipment in the secondary power distribution system, especially the compact and scalable SF6 switchgear has become the leading equipment in the secondary power distribution system. Digital technology, integration technology and electromechanical integration technology are widely used, SF6 switchgear will be greater development.