Research on the Aging Judgment Method of Electrical Performance of C₄F₇N/CO₂ Mixed Gases

Perfluoroisobutyronitrile (C 4 F 7 N) gas exhibits favorable environmental characteristics and excellent electrical performance, which renders it a prominent subject of research in the development of new environmentally friendly insulation materials as a substitute for SF 6 gas. In this study, the decomposition products of a gas mixture comprising 15% C 4 F 7 N and 85% CO 2 were investigated within a 12kV ring main unit. A total of 140 arc tests were conducted on the gas mixture, allowing for the identification of the relationship between the generation of decomposition products and the number of arc tests. Through the determination of the proportional relationship between the different types and quantities of products, a novel method for assessing the extent of electrical performance aging in C 4 F 7 N/CO 2 gas was developed, thus serving as a valuable reference for gas aging assessment. This study is of great significance for promoting the application of C 4 F 7 N/CO 2 mixed gas in power systems.