Investigation of electrically stressed SF4 gas by using FT-IR spectroscopy

Compressed gaseous sulphur hexafluoride is commonly used as an insulating medium in high-voltage equipment. In the presence of traces of oxygen and moisture, SF6 can undergo decomposition under electrical stress. FT-IR-spectroscopic methods provide the possibility for a multicomponent trace gas analysis in the SF6-matrix with the option of on-line measurements. Decomposition compounds, produced by partial discharges, can be determined by multivariate spectral data analysis. Time-dependent concentration changes of the SF6 impurities in different infrared gas cells have been evaluated.