In small current grounding system, determining singlephase grounding fault lines is quick a key question for realizing protection of power distribution net. Studies at the paper as follows was outspreads: a method of malfunction lineselection using the size and direction of zero sequence full current was advanced in neutral point indirect grounding system on the base of studying malfunction lineselection methods. Besides, a new method of lineselection using zero sequence transient electric charges for identifying singlephase grounding fault was put forward. This method is suit for neutral point to the ground via arcsuppression coil system. Computer simulation results indicate that the method has the merit of high lineselection accuracy rate and is propitious to implement microcomputer lineselection devices.