Liquefaction of SF6 can lead to insulation or interruption failures in switchgears that are installed in high-latitude low-temperature regions. Consequently, mixtures are widely used in gas circuit breakers in these regions. The status of the switchgear equipment affects the safe operation of power grids directly, the location of faults and diagnosis of defects are mainly detected by gas decomposition products at present. Consequently, we performed a series of mixture gas decomposition tests on a SF6/N2 gas-insulated circuit breaker after breaking current, studied the characteristic components of the decomposition products, and analyzed the effects of different arc energy and N2 content on the decomposition products of the mixed gas. It is found that the decomposition products of SF6/N2 mixture in the presence of electric arc detected by gas chromatograph are mainly CF4, CO2, SO2, and SOF2. The concentration of these decomposed products increases with arc energy and time increases. With the same arc energy, the higher the proportion of SF6 in the mixed gas is, the higher the decomposition products content will be. And the influence of SF6 ratio on (SO2+SOF2)/ (CO2+CF4) is also obtained.The studies can provide a reference for the diagnosis of internal defects of SF6 mixed gas.
KEY WORDS :arc;SF6 gas;decomposition characteristics;gas analysis;arcing energy;
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