Abstract: Based on the introduction of the self triggering principle of series compensation spark gap（ GAP）,combined with the self triggering phenomenon of spark gap of a line series compensation during the fault outside the500 kV adjacent line area,this paper analyzes the waveform during the fault in detail,judges the cause of gap self triggering,and puts forward some solutions suggestions to avoid excessive inspection of equipment,which resulting in the failure of high-voltage transmission line to operate under its optimal operation mode,and affects the stability of power system.