No abstract

SF, the most widely used electrical-equipment-insulation gas, has serious greenhouse effects. CFO has attracted much attention as an alternative gas in recent two years, but the environmental impact of its decomposition products is unclear. In this work, the decomposition characteristics of CFO were studied based on gas chromatography-mass spectrometry and density functional theory. We found that the amount of decomposition products of CFO, namely, CF, CF, CF, CF, CF, and CF, increased with increased number of discharges. Under a high-energy electric field, the C-C bond of CFO between carbonyl carbon and α-carbon atoms was most likely to break and generate CFCO•, CF• or CFCO•, CF• free radicals. CF•, and CF• free radicals produced by the breakage more easily recombined to form small molecular products. By analyzing the ionization parameters, toxicity, and environmental effects of CFO and its decomposition products, we found that CFO gas mixtures exhibit great decomposition and environmental characteristics with low toxicity, with great potential to replace SF.

No abstract

This paper explores the decomposition characteristics of a new type of environmentally friendly insulating gas C 6 F 12 O and N 2 mixed gas under AC voltage. The breakdown behavior of 3% C 6 F 12 O and N 2 mixed gas in quasi-uniform field was investigated through a breakdown experiment. The self-recovery of the mixed gas was analyzed by 100 breakdown experiments. The decomposition products of C 6 F 12 O and N 2 under breakdown voltage were determined by gas chromatography-mass spectrometer (GC-MS). Finally, the decomposition process of the products was calculated by density functional theory, and the ionization energy, affinity, and molecular orbital gap of the decomposition products were also calculated. The properties of the decomposition products were analyzed from the aspects of insulation and environmental protection. The experimental results show that the 3% C 6 F 12 O and N 2 mixed gas did not show a downward trend over 100 breakdown tests under a 0.10 MPa breakdown voltage. The decomposition products after breakdown were CF

SF6 is widely used in all kinds of high-voltage electrical equipment because of its excellent insulation and arc-extinguishing performance. However, this compound leads to serious greenhouse effect, which harms the environment. Many research institutions are now actively in search of SF6 alternative gas. C5F10O has attracted much attention as an alternative gas with low global warming potential (GWP) and excellent dielectric strength. In this paper, we analyzed the possible decomposition paths of C5F10O under micro-water environment through density functional theory. We also evaluated the ionization parameters and toxicity of the decomposition products. The results show that OH• and H• produced by H2O exhibited a catalytic effect on the decomposition of C5F10O. CF4, C2F6, C3F6, C3F8, C4F10, C5F12, C6F14, C3F7COH, C3F7OH, CF3COH, C3F7H, and CF3OH were produced in the micro-water environment. Based on molecular configuration calculation, the ionization parameters of these products were inferior to perfluorocarbons, such as C3F8, leading to reduced insulation performance of the system. Moreover, CF2O and HF are hazardous to human health and equipment safety. Results will provide a basis for further study of the insulation characteristic of the C5F10O gas mixture under micro-water condition to guide the formulation of their relevant international standards prior to engineering applications.