SF6 leak detection of high-voltage installations using TEA-CO2 laser-based DIAL

SF6 is known as an effective insulator due to its high dielectric strength. Because of this property, it is vastly used in the sealed high-voltage (HV) installations and compact electrical distribution sites. Since then, sensing of SF6 leakage takes significant environmental and economical advantages due to its high greenhouse effect. Here, we have quantitatively shown that our homemade differential absorption lidar (DIAL), using a pair of pulsed CO2 lasers, enables us to detect efficiently remote SF6 effluent up to ppm level. Moreover, the instantaneous spatial distribution of SF6 emission were recorded at various meteorological conditions to indicate that SF6 molecules are reluctant to diffuse quickly, willing to accumulate over the ground at definite location. The lidar attenuation and backscattering coefficients were determined for three typical meteorological conditions based on the best fitting using the least-square method. In addition, according to the spectral response, the remote isotopic identification of the abundant 32SF6 and rare 34SF6 species were done using dual tunable TEA-CO2 lasers. Logarithmic derivative and Klett inversion approximations were subsequently used to determine SF6 concentration based on DIAL equation.