Decomposition of SF6-free gas mixtures by energy impacts

Abstract

For in-door application of medium voltage gas insulated switchgear (MV GIS) it is essential to know the environmental, health and safety (EHS) risks caused by the release of the used gaseous dielectric, particularly after degradation due to the arc lightning that comes along with switching operations. SF6-free and halogen-free gas mixtures that consist of natural gases (main components of ambient air, e.g. N2, CO2 and O2) were tested at different voltage and current levels in this study. Decomposition products of the gas that occurred after switching operations were analyzed by means of Fourier-transform infrared absorption spectroscopy (FTIR) both qualitatively and quantitatively. Concentrations of carbon monoxide (CO) and nitrogen oxides (NOx) have been detected in the gas samples.In case of accidental gas release safety related exposure limits will not be exceeded.