In SF6 electrical equipment, what is the effect of solid insulation surface condition on surface discharge, and what are the countermeasures?- 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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In SF6 electrical equipment, what is the effect of solid insulation surface condition on surface discharge, and what are the countermeasures?

发布时间：2016-12-15 来源：ydlcb 浏览次数：36次

The flashover voltage will be significantly reduced if the solid insulation surface is contaminated and affected by moisture.

The source of surface contamination is likely to be impurities during equipment assembly and metal particles generated during switch operation, which will reduce flashover voltage and increase dispersion. In addition, arc discharge and corona discharge during operation will cause SF6 gas decomposition to produce low fluoride SF4, SOF2, SO2F2, etc. Under the action of water and oxygen, corrosive HF and SO2 will be generated, making the insulation material corroded and deteriorated, and the insulation resistance will be reduced. Due to the high temperature effect, arc discharge will cause the electrode to volatilize and generate metal fluoride powder, which will adhere to the solid insulation surface after the action of water and reduce the insulation strength.

The SF6 gas in the electrical equipment has a certain humidity, and air and water vapor may also be immersed in the equipment at the equipment seal. In addition to the water in the SF6 gas in the equipment, in addition to the deterioration of the insulation due to the action of SF6 decomposition, when the temperature increases or the equipment is suddenly cooled and heated, the water will condense on the insulation surface and greatly reduce the flashover voltage.

In order to prevent solid surface pollution and moisture, insulation materials with good corrosion resistance should be selected, especially materials containing SiO2 (SiO2 is susceptible to acid etching) should be avoided, such as polytetrafluoroethylene with good arc resistance and acid resistance should be selected at the switch arc extinguishing nozzle. In the process, attention should be paid to cleaning, sealing should be strengthened, and SF6 gas humidity should be strictly controlled, in addition, adsorbent should be placed in the electrical equipment to absorb gas humidity and the resulting decomposition.