A small, faulty line current

The invention discloses a low-current grounding wire-selecting method, which is characterized by comprising the following steps: 1) distribution network neutral point displacement voltage is used as a characteristic parameter to correctly identify whether a single-phase grounding fault happens in the distribution network; 2) if the grounding fault happens, grounding current at the fault point is compensated by an arc-suppression coil so as to reduce grounding current and extinguish grounding arc light; 3) a switch mechanism between the neutral point and the arc-suppression coil is switched off to make the arc-suppression coil out of operation in a short time; 4) circuits with single-phase grounding faults are selected by analyzing the change value of zero-sequence current of each circuit before and after the arc-suppression coil exits; and 5) the arc-suppression coil is added again after the fault circuits are selected so as to ensure the arc-suppression coil to play a role of compensation. Circuits with single-phase grounding faults can be accurately selected in the method disclosed by the invention.