Fundamental study on practical application of high-performing and environmentally-friendly CF3I gas insulation system

CF 3 I气体是SF6气体的替代气体之一，用于电力设备，具有如下优点：CF 3 I的绝缘性能在均匀电场中相当于或上级SF6，其全球变暖潜值（GWP）与CO2相当低。但在非均匀磁场中，它的击穿电压较低。新的洁净绝缘子在CF_3I气体中的沿面闪络电压比SF_6气体中高1 ~ 1.2倍。由于CF 3 I气体的饱和蒸气压低，因此为了防止CF 3 I挥发，通过混合其它气体来有效地减少CF 3 I气体分压的降低。系统地研究了CF_3I/N_2、CF_3I/CO_2和CF_3I/SF_6混合气体的绝缘特性。通过这些讨论，提出了最佳的气体是CF_3I/N_2混合气体，它可以实际应用于气体绝缘输电线路，GIL。

CF3I gas is one of alternatives to SF6 gas, which are utilized for electric power equipment, and has some advantages as follows: the insulation performance of CF3I is equivalent or superior to SF6 in uniform field and its global warming potential, GWP, is quite low as same as CO2. It has, however, a low sparkover voltage in non-uniform field. The surface flashover voltage on a new and clean insulator in CF3I gas is 1-1.2 times higher than that in SF6 gas. As the saturated vapor pressure of CF3I gas is low, the reduction of partial pressure of CF3I gas is effectively reduced by mixing other gases in order to prevent CF3I from devolatilization. The insulation characteristics of CF3I/N2, CF3I/CO2 and CF3I/SF6 mixtures are systematically investigated. Through these discussions, it is proposed that the most optimum gas is CF3I/N2 mixture and that it can be practically applied to gas insulated transmission lines, GIL.