Fault line selection and location of neutral earthing via arc extinguishing coil system

In the power system, neutral grounding is usually adopted in small current neutral grounding system whose voltage grade does not exceed 60 kV. In this way, if a single-phase ground fault occurs, due to that line voltage is still symmetric and fault-phase grounding current is very small, this system can still run 1 to 2 hours to improve the power supply reliability. However, in order to prevent the fault range expansion, the fault line selection and location are still needed. For the problem of weak single-phase ground fault signal in small current neutral grounding system, it proposes a method by injecting a specific frequency current signal, the method can quickly solve the question of fault line selection and location.