Environmentally Friendly Insulating Gases as SF6 Alternatives for Power Utilities

Sulfur hexafluoride (SF6) has been widely used as an insulating gas medium in various electrical equipment due to its excellent insulation and arc extinguishing properties. Compared to other insulating media, SF6 not only improves the insulation strength of equipment but also reduces equipment size. However, SF6 is now known as an extremely strong greenhouse gas with a Global Warming Potential (GWP) of 23,500 times of carbon dioxide. Additionally, the atmospheric lifetime of SF6 is 3,200 years. Therefore, SF6 was listed in the Kyoto Protocol in 1997 as one of six gases targeted for emission reduction. Today nearly 80% of the globally produced SF6 is used in the power industry with the annual production exceeding 10,000 tons. 3M has sought to provide the industry with more sustainable alternatives for SF6, in research that spans over 20 years. 3M scientists have evaluated hundreds of compounds to identify materials with the right combination of performance, safety and environmental properties. After extensive testing under laboratory and field conditions, 3M has developed and commercialized 3M (TM) Novec (TM) Insulating Gases. Two new 3M Novec Insulating Gases consist of Novec 5110 Insulating Gas (C5 fluorinated ketone) and Novec 4710 Insulating Gas (C4 fluorinated nitrile). 3M Novec Insulating Gases are nonflammable, non-ozone depleting materials that offer up to twice the dielectric strength and significantly lower global warming potential than SF6. In fact, Novec Insulating Gases could reduce potential greenhouse gas emissions by 98% or more. 3M has worked closely with well-known industry leaders in the world of power generation and transmission infrastructure, to support the development of several Novec insulating gas mixtures that are optimized for various applications and environmental conditions. Today these solutions will help maintain the safety and reliability of medium and high voltage systems, while reducing reliance on materials that negatively impact the environment. This paper will review these recently-implemented, insulating gases with updates on the performance, safety and environmental profiles in electrical power applications.