The electrical characteristics of a single-phase grounding fault in a low-resistance grounding system was aualyzed, and a fault protection scheme was proposed for low-resistance grounding systems according to the ratio of the zero-sequence current projection components. The primary line selection was performed according to the zero-sequence current projection method and then the phase difference value was used for the secondary judgment. The proposed protection scheme was verified by Matlab/Simulink. The simulation results show that the scheme has a certain ability to withstand transition resistance, which effectively improves the sensitivity of the ground fault protection.