Laser sensor for detection of SF/sub 6/ leaks in high power insulated switchgear systems

A novel photoacoustic spectrometer (PA) has been developed for in-situ detection of SF/sub 6/ leaks in low concentrations. The developed system is equipped with a sound alarm system and has been tested in the laboratory for very minute SF/sub 6/ leaks. This newly developed SF/sub 6/ detection device utilizes a high quality factor resonant photoacoustic cell and continuous wave (CW) line tunable CO/sub 2/ laser at 10.55 /spl mu/m wavelength. Whenever SF/sub 6/ is detected an acoustic signal is generated and no signal appears from ambient air if there is no leakage of SF/sub 6/. An electret microphone is used for the detection of these acoustic signals. The system is capable of detecting leaks of the order of 3.5 ppbv (parts per billion by volume) concentration. This device has been proved to have significant applications to industrial organizations that have electric power gas insulated systems (GIS). It could be also applied for other applications such as monitoring of environmental pollutants with minimal adjustments.