Recent Development of Alternative Gases to SF6for High Voltage Electrical Power Applications

For many years, SF
₆
has been the preferred dielectric medium in electrical power applications, particularly in high voltage gas-insulated equipment. However, with the recognition that SF
₆
has an extremely long atmospheric lifetime and very high global warming potential, governments have pursued emission reductions from gas-filled equipment. The electrical power industry has responded to this environmental challenge applying SF
₆
-free technologies to an expanding range of applications which have traditionally used SF
₆
, including both gas-insulated switchgear and gas-insulated lines or bus bars. Some of these SF
₆
-free solutions include gas mixtures containing fluorinated compounds that have low climate impact, among them, a fluoronitrile and a fluoroketone developed as 3M™ Novec™ 4710 Insulating Gas and 3M™ Novec™ 5110 Insulating Gas, respectively. Both fluoronitrile and fluoroketone mixtures are successfully used in gas-insulated equipment currently operating on the grid. This paper will review these recently implemented components of insulating gas mixtures with updates on the performance, safety and environmental profiles in electrical power applications.