切向电场主导下 C₄F₇N/CO₂混合气体中环氧复合材料表面电荷积聚特性及机理研究

Charge accumulation at gas⁃solid interface is an important cause of surface flashover.The charge accumu⁃ lation characteristics in C4F7N/CO2 mixtures have not been sufficiently studied. To investigate the characteristics and mechanism of surface charge accumulation in C4F7N/CO2 mixture，the surface charge distribution characteristics of epoxy composite insulation in C4F7N/CO2 mixture were measured by constructing a severe non⁃uniform electric field with finger⁃type electrode. In order to further clarify the surface charge accumulation mechanism，the surface poten⁃ tials of the material in the C4F7N/CO2 mixture were measured under the impulse voltage and were compared with that after attaching a back⁃plate electrode. The study shows that the surface potential distribution in the C4F7N/CO2 mix⁃ ture is similar to that in SF6，showing that a large number of homopolar charges accumulate near the high voltage elec⁃ trode and a small number of heteropolar charges accumulate near the ground electrode. As the C4F7N content rises，the charge suppression ability of the C4F7N/CO2 mixture increases. The surface charges are derived from gas ioniza⁃ tion and electrode injection and the mechanism is converted with the electric field. With the tangential electric field facilitating，the charges migrate along the surface to a larger area. This work is of great significance for the clarifica⁃ tion of the surface charge accumulation characteristics in C4F7N/CO2 mixture and the promotion of eco⁃friendly insula⁃ tion gas applications.