Breakdown Characteristics of Eco-Friendly Gas C₅F₁₀O/CO₂ Under Switching Impulse in Nonuniform Electric Field

In this article, an experimental study was carried out on the switching impulse (SI) breakdown characteristics of C ₅ F ₁₀ O/CO ₂ mixture, and the effects of pressure and mixing ratio on its breakdown characteristics were analyzed. The results show that there is a polarity effect between positive and negative breakdown voltages, and the polarity effect becomes stronger with the pressure increased, and a polarity reversal occurred at 0.15 MPa. Increasing the gas pressure and the content of C ₅ F ₁₀ O can improve the SI breakdown voltage of C ₅ F ₁₀ O/CO ₂ , but it can only reach 60%–70% of SF ₆ under the same conditions. The positive breakdown voltage has a “hump” phenomenon as the pressure increases. With the increase in C ₅ F ₁₀ O content, the “hump” tends to shift toward low pressure. The “hump” is explained from the improving effect of positive space charge on electric field, and the influence of the applied voltage, pressure, and C ₅ F ₁₀ O content on the positive charge layer is comprehensively considered. The results of this article can provide reference for the engineering application of C ₅ F ₁₀ O gas insulating medium.