C4F7N/CO2 mixed gas is one of the most promising alternatives to SF6

but there is currently a lack of research on the optical characteristics and diagnostic methods of defect discharge under this gas environment. Therefore

this paper investigates the emission spectrum of C4F7N/CO2 mixed gas under a direct current environment

clarifying the influence characteristics of different electrode materials on the emission spectrum of the mixed gas under an extremely non-uniform electric field breakdown. The study shows that

under the same conditions

the emission spectrum characteristic peaks of the C4F7N/CO2 mixed gas are more prominent than those of SF6

with the relative intensity of the highest peak reaching 234.03% of SF6. Different electrode materials exhibit unique emission spectral lines

but the overall spectral shapes are very similar. Different electrode materials also affect the relative intensity of common spectral lines. When the spectral ratios of 358.4 nm and 521.8 nm

407.5 nm and 601.2 nm

and 396.1 nm and 777.2 nm based on the relative strength relationship of characteristic spectral lines are selected as discriminative features

the electrode materials can be effectively identified.