CF3I Gas Mixtures: Breakdown Characteristics and Potential for Electrical Insulation

SF6 is a potent greenhouse gas, and there has been research into more environmentally-friendly alternative gases with the aim of replacing the use of SF6 gas in high-voltage equipment. So far, the research into alternative gases has shown that CF3I gas mixtures have promising dielectric properties comparable to those of SF6. This paper provides an overview of research into CF3I gas and its mixtures, and gives an insight into its key properties. These include laboratory tests on the gas mixtures and initial applications to electrical power equipment. The insulation capability makes CF3I a feasible alternative to SF6 as an insulation medium where arc quenching is not required. On the other hand, iodine deposition after electrical discharge means CF3I mixture may not be a suitable arc quenching gas for switchgear applications that require high current interruption unless a solution is found for controlled capture of the iodine.