## 1 Introduction  
Sulfur hexafluoride (SF\({}_{6}\)) is widely used in gas-insulated switchgear (GIS), compact GIS (c-GIS), and other high-voltage power equipment due to its exceptional insulation and arc-extinguishing properties [1]. However, SF\({}_{6}\) has a global warming potential (GWP) of 23,500 and an atmospheric lifetime exceeding 3200 years, making it one of the six most harmful greenhouse gases [2, 3]. Studies indicate that the global average temperature could rise by more than 4 \({}^{\circ}\)C by 2100 [4, 5]. In line with global environmental protection initiatives, reducing SF\({}_{6}\) usage in power equipment has become a critical priority. Consequently, there is an urgent need to develop an alternative insulating gas that balances both insulation performance and environmental sustainability. In recent years, perfluoroketone (C\({}_{n}\)F\({}_{2}\)nO) insulating media have attracted significant attention from researchers worldwide due to their excellent insulation performance and favorable environmental properties [6, 7]. As a member of this family, perfluorom-ethylvinyl ether (PMVE) gas is emerging as a research hotspot. PMVE exhibits very low global warming potential and zero ozone depletion potential (ODP), meaning that perfluoroketones do not deplete the atmospheric ozone layer, in accordance with the 'Montreal Protocol on Substances that Deplete the Ozone Layer' [8]. Some scholars have explored the potential of PMVE as a substitute for SF\({}_{6}\) from the perspective of the total electron scattering cross-section (TCS) [9]. For instance, [PERSON] et al. investigated the electron collision-scattering behavior of PMVE and revealed that its critical dielectric strength (475 Td) is higher than that of SF\({}_{6}\) (355 Td) [10]. Additionally, [PERSON] and [PERSON] compared the partial discharge characteristics of PMVE and SF\({}_{6}\) under different pressures using a comprehensive insulation performance test platform. Their findings demonstrated that PMVE exhibits a small difference between the initial voltage of local discharge (PDIV) and the extinction voltage (PDEV), as well as a stable breakdown voltage, which is advantageous for suppressing discharge and indicates its potential to replace SF\({}_{6}\)[11]. Despite its excellent insulation capabilities, PMVE's liquefaction temperature is higher than that of SF\({}_{6}\), necessitating its mixture with inert gases such as CO\({}_{2}\) or N\({}_{2}\) to enhance both safety and insulation performance. CO\({}_{2}\) is widely regarded as a greenhouse gas and is commonly used to measure the atmospheric greenhouse effect. Its liquefaction temperature is higher than that of N\({}_{2}\), which has a global warming potential (GWP) value of 0. According to the GWP calculation formula stipulated in regulations [12], the use of N\({}_{2}\) in combination with PMVE does not exacerbate the overall greenhouse effect but instead promotes environmental protection. N\({}_{2}\), as an inert gas with strong chemical stability and an extremely low liquefaction temperature, is frequently mixed with insulating gases that have higher liquefaction temperatures [13; 14]. [PERSON]'s team investigated the synergistic effects of mixing PMVE with N\({}_{2}\) and found that the combination enhanced the insulation performance of the gas mixture. As the proportion of PMVE increased, the insulation performance improved, and when the PMVE/N\({}_{2}\) mixing ratio approached 6:4, the insulation performance of the mixture was comparable to that of SF\({}_{6}\)[10]. Currently, most research primarily focuses on the insulation characteristics of PMVE, with limited studies on its decomposition properties. Gas-insulated switchgear (GIS) systems inevitably experience faults, such as discharge and overheating, during operation.