Those who have used sulfur hexafluoride gas know that sulfur hexafluoride gas is very important for water control. High water content will cause corrosion damage to sulfur hexafluoride equipment and affect its working effect. Then when filling SF6 gas, why should specific requirements for environmental humidity be put forward? What should I pay attention to when filling?

Moisture is a condition for the production of toxic substances in SF6 equipment. If SF6 gas contains more than the specified moisture, when the humidity changes, it may condense on the solid insulation surface to make the surface moist, then the equipment's surface discharge voltage will drop significantly. SF6 gas is decomposed into low-fluorine compound gas under the action of arc and corona. SO2, HF and other harmful substances would not have been generated without the external condition of water molecules, thus equipment corrosion generated by them could be avoided. Therefore, strict measures must be taken to prevent moisture from entering SF6 equipment when filling gas.

(1) Before the start of the work, the relative humidity of ambient air around the site should be determined ≤ 80% (i.e., the fraction of water vapor density in the air and the density ratio of saturated water vapor at the same temperature), which is the specific indication of water content in the restricted air. If the determination fails, measures should be taken or refilled in dry and sunny weather.

(2) In order to ensure the timely discharge of SF6 leakage gas, the main tip should start the fan while filling, and the air SF6 content should not exceed 1000ppm. The test should be carried out within a certain time after the start of the work, and the test side should be carried out again in the middle of the work. When SF6 gas content increases or exceeds the standard, the component should be inspected in detail immediately to find out the cause and eliminate it.