CF3I has been widely considered as a potential alternative for SF6,because it has low global warming potential(GWP)but an insulation capability that is 1.2 times greater than that of SF6.In this paper,the electron swa...CF3I has been widely considered as a potential alternative for SF6,because it has low global warming potential(GWP)but an insulation capability that is 1.2 times greater than that of SF6.In this paper,the electron swarm parameters of CF3I and its gas mixture with N2,including the effective ionization coefficient and electron drift velocity,are examined theoretically through the Boltzmann equation method in the condition of steady-state Townsend(SST)experiments.Based on the derived data of the limiting field strength of CF3I-N2gas mixture,taking into consideration of environmental aspects such as GWP,ozone depletion potential(ODP),liquefaction temperature and toxicity,we studied the possibility of applying the gas mixture as the insulation medium in gas-insulated switchgears(GIS)or cubic type gas-insulated switchgears(C-GIS).It is found that CF3I-N2gas mixtures contained 30%～70%CF3I perform comprehensively better than pure SF6and compressed N2,and especially in medium and low voltage environments,the boiling point of CF3I-N2gas mixture meets the domestic and global requirements in mid-low latitude regions.Therefore we conclude that the gas mixture is acceptable for replacing SF6as the insulation medium in C-GISs.展开更多
It is necessary to find an efficient selection method to pre-analyze the gas electric strength from the perspective of molecule structure and the properties for finding the alternative gases to sulphur hexafluoride （...It is necessary to find an efficient selection method to pre-analyze the gas electric strength from the perspective of molecule structure and the properties for finding the alternative gases to sulphur hexafluoride （SF6）. As the properties of gas are determined by the gas molecule structure, the research on the relationship between the gas molecule structure and the electric strength can contribute to the gas pre-screening and new gas development. In this paper, we calculated the vertical electron affinity, molecule orbits distribution and orbits energy of gas molecules by the means of density functional theory （DFT） for the typical structures of organic gases and compared their electric strengths. By this method, we find part of the key properties of the molecule which are related to the electric strength, including the vertical electron affinity, the lowest unoccupied molecule orbit （LUMO） energy, molecule orbits distribution and negativeion system energy. We also listed some molecule groups such as unsaturated carbons double bonds （C=C） and carbonitrile bonds （C=N） which have high electric strength theoretically by this method.展开更多
基金Project supported by National Natural Science Foundation of China （51177101）
文摘CF3I has been widely considered as a potential alternative for SF6,because it has low global warming potential(GWP)but an insulation capability that is 1.2 times greater than that of SF6.In this paper,the electron swarm parameters of CF3I and its gas mixture with N2,including the effective ionization coefficient and electron drift velocity,are examined theoretically through the Boltzmann equation method in the condition of steady-state Townsend(SST)experiments.Based on the derived data of the limiting field strength of CF3I-N2gas mixture,taking into consideration of environmental aspects such as GWP,ozone depletion potential(ODP),liquefaction temperature and toxicity,we studied the possibility of applying the gas mixture as the insulation medium in gas-insulated switchgears(GIS)or cubic type gas-insulated switchgears(C-GIS).It is found that CF3I-N2gas mixtures contained 30%～70%CF3I perform comprehensively better than pure SF6and compressed N2,and especially in medium and low voltage environments,the boiling point of CF3I-N2gas mixture meets the domestic and global requirements in mid-low latitude regions.Therefore we conclude that the gas mixture is acceptable for replacing SF6as the insulation medium in C-GISs.
基金supported by National Natural Science Foundation of China(Nos.51177101 and 51337006)
文摘It is necessary to find an efficient selection method to pre-analyze the gas electric strength from the perspective of molecule structure and the properties for finding the alternative gases to sulphur hexafluoride （SF6）. As the properties of gas are determined by the gas molecule structure, the research on the relationship between the gas molecule structure and the electric strength can contribute to the gas pre-screening and new gas development. In this paper, we calculated the vertical electron affinity, molecule orbits distribution and orbits energy of gas molecules by the means of density functional theory （DFT） for the typical structures of organic gases and compared their electric strengths. By this method, we find part of the key properties of the molecule which are related to the electric strength, including the vertical electron affinity, the lowest unoccupied molecule orbit （LUMO） energy, molecule orbits distribution and negativeion system energy. We also listed some molecule groups such as unsaturated carbons double bonds （C=C） and carbonitrile bonds （C=N） which have high electric strength theoretically by this method.
