482 / 2022-03-16 12:42:01

Photoacoustic spectroscopy-based SF6 sensor for gas leakage measurement of high-voltage insulation devices

Photoacoustic spectroscopy,,SF6,optical gas sensor,gas leakage

   Sulphur hexafluoride (SF₆) has been widely applied in high-voltage and media-voltage power apparatuses due to high chemical stability and insulation strength. In recent years, many sensing techniques had been developed for rapid field measurement of SF₆ concentration, such as non-dispersive infrared sensor and gas chromatograph analyzer. However, these sensing methods suffer from bulky size, low sensitivity and low selectivity. A quartz-enhanced photoacoustic spectroscopy-based sensor with continuous-wave distributed-feedback quantum cascade laser of 10.5 um and quartz tuning fork is proposed for concentration measurement of SF₆. The tiny quartz tuning fork is used to capture the sound wave generated by gas absorption. We use wavelength stabilization method to lock the laser wavelength near the absorption peak of target gas. The minimal detection limit of proposed sensor achieves 5 ppb and the time resolution is 0.5 s. For the SF₆-based insulation devices, the photoacoustic spectroscopy-based sensor could successfully detect the gas leakage under different outdoor meteorological conditions.