Decomposition product formation mechanism of C₅F₁₀O-CO₂ mixture in corona discharge by a chemical kinetic model

Abstract C 5 F 10 O-CO 2 mixture has great potential to replace SF 6 in gas-insulated equipment. However, C 5 F 10 O-CO 2 mixture can decompose to a series of products in corona discharge, weakening the insulation performance of the gas-insulated equipment. The formation mechanism of the decomposition products can help identify the potential insulation defects. This paper establishes a chemical kinetic model to obtain the variation regulation of decomposition products in AC point-plane corona discharge for C 5 F 10 O-CO 2 mixture with C 5 F 10 O content of 5%, 10% and 15%. The model is composed of a plasma region and a gas region, and the two regions interact via a diffusion process. The model contains 78 species and the related reactions. Multi-step time is applied to simultaneously calculate the rapid chemical reaction kinetics in the plasma region and the slow chemical reactions in the gas region. The effects of O 2 on the decomposition products are also investigated by the addition of 10%O 2 in 10%C 5 F 10 O–90%CO 2 mixture. The main reaction pathways in the plasma and gas regions are captured by calculating the contributions of the related reactions to the generation of decomposition products. By analyzing the formation mechanism of the decomposition products, the main physicochemical processes in corona discharge can be obtained.