US EPA SF6 Partnership
Workshop
May 7, 2014
Insulating is also known as a dielectric gas.
Dielectric gas (click here) is a form of gas used in industrial applications as an electrical insulator. Common types of gasses used include air, nitrogen, and sulfur hexafluoride. Various types of electrical components such as transformers and circuit breakers require the presence of a dielectric gas to prevent damage to a circuit in the case of an electrical discharge. In routine applications, air is often the dielectric gas of choice because it doesn't require a pressurized, sealed system, and is ubiquitous....
...Sulfur hexafluoride is used as a dielectric gas in high-voltage switchgear such as industrial circuit breakers that connect generators to step-up voltage transformers. It is also used in areas of high voltage electric power systems that require gas insulators, such as transmission lines, transformers and substations. Around 80% of all the sulfur hexafluoride manufactured is commonly used in electrical power plants and substations throughout the world due to its superior insulating qualities and ability to suppress radio wave and sound wave transmission from electrical equipment. It also has the highest level of breakdown voltage for any insulating gas, which is the level of voltage necessary for a dielectric gas to begin conducting current and fail to act as an insulator.
Disadvantages to using sulfur hexafluoride as a dielectric gas are significant, however, and, for this reason, attempts are being made to combine it with safer gasses, such as nitrogen, carbon dioxide, or perfluorocarbon compounds....
Of the three gases sulfur hexafluoride can be mixed with nitrogen is the only one that isn't a greenhouse gas.
