Analysis of the feasibility of CF<suv>3I/CO2 used in C-GIS by partial discharge inception voltages in positive half cycle and breakdown voltages.

SF6 is widely used in C-GIS as an insulating medium. However, SF6 and its decomposition products can pollute environment and harm human health and equipment. Firstly, this paper verifies the high-energy discharge promotes CF3I to produce C2F6 and I2 by simulation. Therefore the paper puts forward the significance of using mixture gas to reduce the use of CF3I and control the produce of I2. Secondly, the partial discharge inception voltages in the positive half cycle of power frequency (PDIV+) of CF3I/CO2 under different pressures, mixing ratios (k) and interelectrode distances were measured and compared with SF6/CO2. The results show that: when k is more than 10%, the PDIV+ of CF3I/CO2 is close to or higher than SF6/CO2 in the same experimental conditions; The PDIV+ of CF3I/CO2 (30%-40%) at 0.15-0.2MPa can reach the level of pure SF6 in 0.1MPa. The breakdown experiments under different electric fields shows that the breakdown characteristic of CF3I/CO2 (30%-40%) at 0.15-0.2MPa can exceed the level of pure SF6 at 0.1MPa. Considering the boiling point, producing of I2 and insulating property, CF3I/CO2 (30%-40%) is likely to replace SF6 used in C-GIS. [ABSTRACT FROM AUTHOR]