SF6 or sulfur hexafluoride gas, is a widely refrigerant gas in gas-insulated substations and circuit breakers. However, its use poses multiple environmental safety challenges, especially when it concerns maintenance. Units handling SF6 Gas need to be aware of the latest tools that detect and mitigate leaks, information to access gas purity, and the best practices of handling it safely.
Here are some considerations and best practices for SF6 gas management.
SF6 GAS MANAGEMENT
1. Equipment – The equipment type and the environment in which the gas in being used, determines the risk levels, protection needed and the handling procedures. Equipment types may either be non-switching, for example, gas-insulated transmission lines, or switching, for example, circuit breakers.
2. Risks & Warning signs – The risks and warnings involved in handling SF6 gas can be of three levels, namely high, medium and low. High risk situation would involve the cleanup of the gas, post an arcing fault. The gas, at this stage may leak harmful, highly toxic gases, which may even require evacuating the work area. A medium risk situation would be when the SF6 gas is undergoing a routine maintenance and when the equipment is being opened. The by-products of this gas may leak then, and pose hazards. Protective gear must be worn at this stage hence. Lastly, a low risk situation would be working with a problem-free or new equipment. Safety measures, such as ensuring that it’s being worked on in a well-ventilated area, controlling arc welding, and refraining from smoking within the premises, should suffice.
3. Handling – Safe handling of the gas would involve ensuring that the cylinder isn’t dropped and it’s kept away from heat. It should never be stored in sunlit areas and the cylinder’s temperature should never exceed 50 degrees. The handling unit should be equipped with a filtering system, vacuum pump, compressor and a storage vessel and timely measurement of leakage, moisture content and pressure should be preformed.
4. Disposal – Although the impact of SF6 leaks in the environment isn’t high, leaks should be kept at a minimum. In case of leaks, it should be stored and transported to purification locations for proper handling.
5. Storage & transportation – During transportation, the gas should be constantly monitored for pressure and temperature. Cylinders should always be kept upright during transport and they should never be lifted from their protective caps. Further, detailed regulations are determined by respective state laws.
