Abstract: Compare with low-Impedance faults(LIFs), the high-impedance faults(HIFs) in the small current neutral grounding system has a small fault current, poor stability, so that the diagnosis are more difficult. In recent years, the isolation technique level of small current grounding fault has been improved, a variety of line selection and location instruments have come to fore in the actual scene. However, the accuracy of HIFs are lower than that of the LIFs or bolted single-phase faults. To solve the above problem, this paper introduces the research and demonstration application in two cities of Fujian province, including the neutral grounding system in Quanzhou and the arc-suppression coils system in Longyan, and than verify the fault line selection and location performance.