105 / 2018-08-24 18:12:17

Quantitative Detection of Trace H2S Based on Ultraviolet Differential Optical Absorption Spectrometry

gas-insulated equipment,decomposition component of SF6,ultraviolet spectroscopy,detecting H2S gas concentration

As an important decomposition component of SF6, H2S can provide an important information for the evaluation of insulation state of SF6 electrical insulation equipment. Since H2S has obvious absorption in the ultraviolet range of 190~230nm, the H2S ultraviolet absorption spectrum detection platform is established to realize its detection. In this paper, the SF6 decomposition component detection platform based on ultraviolet spectroscopy was built, and the ultraviolet absorption spectrum of H2S was obtained. Since the ultraviolet absorption spectrum directly obtained by the instrument is susceptible to spectral scattering and high frequency noise, the detection sensitivity is lowered. Therefore, this paper uses the UV differential algorithm to obtain the UV absorption spectrum of H2S by the algorithm of baseline subtraction. After experimental tests, the linear fit R2 of the fitted straight line is as high as 0.999. Moreover, the method has good repeatability for detection of H2S, and the data of five concentrations of 1, 2, 5, 10, and 20 μL/L are measured, and the results show that the absolute error does not exceed 0.2 μL/L. And the noise is calculated by randomly collecting 30 sets of background spectra, and the detection limit is 0.590 μL/L when the signal-to-noise ratio is 1. A method for detecting H2S gas concentration based on ultraviolet differential absorption spectroscopy is proposed, which is suitable for on-line monitoring of trace H2S in the decomposition components of SF6 insulation equipment.