"Kou Jia Yuan" 110 kV  substation and “Guo Jia Wan” 110 kV substation in the shan'xi power grid because the damp environment 、load is bigger、running  long time，Caused by the  arc fault on easy .So  shan'xi power grid decision increase arc protection system in the substations。My company's arc protection system SAQE A200 has been applied and solve the problems. The arc protection plan and function received widely good reputation in the shan'xi power grid.