As a widely used insulating medium, SF6 gas also has some problems in its use. SF6, as an insulating medium, is closely related to the humidity of the gas, that is, the moisture content. Under the action of arc corona, SF6 can chemically react with water to produce strong corrosive substances HF and highly toxic fluoride, endangering the safety of equipment and personnel, and may cause explosion accidents in serious cases. When the humidity of SF6 gas in the equipment is too high, and the water exists in liquid on the surface of the insulating parts, the discharge voltage on the surface of the insulating parts will be reduced, and the internal insulation of the equipment will be reduced. The insulation of the equipment in operation is mainly related to humidity, but also related to other parameters such as temperature, pressure and so on. At the same humidity value measured at different pressures, the insulation level of the equipment is also different. Therefore, content detection and moisture control are very important for safe power supply and water supply.

There are two main standards for the moisture test of sulfur hexafluoride gas:

Standard for moisture test of sulfur hexafluoride gas (20℃, 0.1013MPa)

① circuit breaker interrupter chamber gas chamber: not more than 150ppm after newly inflated, not more than 300ppm in operation;

② No arc decomposition gas chamber: no more than 250ppm after newly inflated, no more than 500ppm during operation.

Do you know where most of the water in sulfur hexafluoride comes from? The main sources of water inside the sulfur hexafluoride equipment are:

① Moisture contained in sulfur hexafluoride new gas;

② Moisture entering the equipment during assembly;

③ Water released from solid insulating objects;

④ Water infiltrated through the seal during operation;

⑤ Water entered during multiple air replenishment and testing during operation;

⑥ air chamber adsorbent failure