Study on CF3I Decomposition Product after Arc Interruption in 12kV Ring Main Unit

SF6 has been widely used in power equipment, however, it has strong greenhouse effect and many countries have made limitations to its use. CF3I is a potential SF6 substitute gas, but there are few studies on the arc interruption decomposition products of CF3I gas. In this paper, the performance of CF3I under different current is experimentally studied by using a 12kV ring main unit. GC-MS method was used to study the decomposition products of CF3I. The results show that the main products of CF3I gas after arc burning are perfluorinated hydrocarbons, including CF4 and C2F6. The solid products are iodine and carbon. After successful arc interruption, CF3I gases decompose in a very small proportion, however, about 96% of CF3I gas is decomposed into CF4 after the failure of interruption. Therefore, on the premise of taking appropriate measures to eliminate solid products in time and ensure the success of arc interruption, The decomposition of CF3I will not affect its application as potential insulating and arc interruption medium in electrical equipment.