Raman Spectra of SF6 Decomposed Characteristic Products Based on Density Functional Theory

Abstract

SF6 decomposition product analysis is one of the most convenient and efficient methods to diagnose the potential faults of SF6 insulated electric equipment in the early stage. Based on SF6 decomposition characteristic gas analysis, the operation state of SF6 insulated power equipment can be judged by on-line monitoring, so as to ensure its normal operation. Raman spectrum analysis technology can realize the nondestructive detection of gas samples with a single wavelength laser. It has excellent applicability and high efficiency for the detection of SF6 decomposition characteristic components. In this paper, molecular configurations of CF4, CO, H2S, SO2 were obtained by B3LYP functional that based on density functional theory (DFT), and the Raman frequency and intensity characteristics were calculated by 6-31G (2df, p) basis group. The results were compared with National Institute of Standards and Technology (NIST) standard frequencies and it was found that the optimized configuration has no virtual frequency. The characteristic peaks of CO, CF4, SO2 and H2S that were identified by Raman spectrum are respectively 2221.11, 908.97, 1175.24 and 2688.82 cm-1, which are basically consistent with the corresponding NIST standard values. This study not only shows that the Raman spectrum of SF6 decomposition products calculated by B3LYP functional function is reliable, but provides a reference for the quantitative detection of SF6 decomposition products based on Raman spectrum.