525 / 2017-05-11 16:35:29

Research on the Microscopic State Parameters of SF6/N2 and SF6/CO2 Circuit Breaker in Arc Formation Process

SF6 substitute gases ,microscopic arc,sheath,dynamic progress

SF6 is widely used in high voltage field for its excellent breaking performance. However, for its high cost and strong greenhouse effect, it is urgently needed to look for new gases with low greenhouse effect index and high insulation performance to substitute. Due to the characteristics of easy access, non-toxic, stable physicochemical properties and non-combustion supporting, N2 and CO2 gases attract a lot of attention of researchers as a possible substitute for SF6. The arc is the key to the success of breaking in circuit breakers. Near cathode and anode sheaths which are generating in the formation process of the arc are the basis of stable arc and have a critical influence on the formation time and the energy parameters of the arc. So the formation processes of arc in SF6/N2 and SF6/CO2 circuit breaker are simulated in this paper from the microscopic point of view, based on the gas dynamics equation and the complex collision reaction of charged particles. The arc dynamic forming process of mixed gas and the time-varying regularity of microscopic electron density, average electron energy, electron temperature are obtained. Mixed gases with different ratios under the same conditions are also simulated. The influence of mixed gas components on the forming process of arc is analyzed. Besides, from the micro perspective, the discharge process of SF6/N2 and SF6/CO2 gas mixtures can be studied deeply, which provides a theoretical basis for the design and manufacture of new type circuit breakers.