Continuous monitoring of SF/sub 6/ degradation in high voltage switchgear using Raman scattering

In high voltage SF/sub 6/ insulated switchgear, the level of SF/sub 6/ concentration needs to be monitored regularly because of its degradation by switching arcs and on-going partial discharges or coronas. In the work reported here, measurements of SF/sub 6/ dissociation rate following 75 /spl mu/A positive and negative coronas have been made using a mass spectrometer and Raman spectroscopy. The two sets of data correlate well, the rates of degradation of SF/sub 6/ and production of gaseous by-products being shown to be proportional to the charge transported by the corona. SF/sub 6/ provides a particularly strong Raman signal at 773.5 cm/sup -1/, and the results demonstrate the feasibility of using Raman scattering to monitor SF/sub 6/ degradation in high-voltage switchgear.