Comparison of Decomposition By-products of C 4 F 7 N/CO 2 Mixed Gas under AC Discharge Breakdown and Partial Discharge

In recent years, C 4 F 7 N has been highly concerned due to its excellent dielectric performance and arcquenching ability. As a potential alternative to SF 6 , the decomposition characteristics of C 4 F 7 N will directly affect its application prospects. However, there are few studies on the decomposition characteristics of C 4 F 7 N mixed gas. Therefore, we conducted AC discharge breakdown experiment and partial discharge experiment on C 4 F 7 N-CO 2 mixed gas, and analyzed the gas decomposition by-products of C 4 F 7 N-CO 2 mixed gas qualitatively and quantitatively by using gas chromatography-mass spectrometry (GC/MS). The results show that the major decomposition by-products under AC discharge breakdown are CO, CF 4 , C 2 F 4 , C 2 F 6 , C 3 F 8 , CF 3 -CN, C 3 F 6 , C 4 F 6 , C 4 F 10 , C 2 F 5 -CN, C 2 N 2 , HCN, C 2 F 3 CN. Under partial discharge, the major decomposition byproducts are CO, CF 4 , C 3 F 8 , CF 3 -CN, C 3 F 6 , C 4 F 10 , C 2 F 5 -CN, C 2 N 2 , HCN, C 2 F 3 -CN. Compared with the partial discharge process, AC discharge breakdown produces more types of decomposition by-products. Besides, AC breakdown tends to produce smaller molecular by-products, while partial discharge tends to produce larger molecular by-products.