Fault diagnosis of electric equipment in operation via SF6 decomposition products detection is an innovative technology
which has been applied to electric power system.The technology has been applied to the electric power system in Qinghai Province since 2008
where SF6 decomposition products detection and fault diagnosis have been performed for several 110 kV
330 kV and 750 kV substations.This paper summarizes and analyzes these works to provide a foundation for further application of the technology in the future.