Faulted Section Identification Method Based on the Transient Current Distribution for the NUGS

The faulted feeder selection and fault identification under the condition of single-phase earth fault in the neutral un-effectual grounded system (NUGS) has long been a problem. As a matter of fact, existing methods that have been proposed may face some difficulty in the case of some scenarios, as the impact of the Petersen coil must be taken into consideration, or when the accurate location of the faulted point is required and the zero-sequence current cannot be measured. To against this, a novel faulted section identification method based on the transient current distribution is put forward by means of theoretical analysis and simulation study. It is shown by the results that this methods can give accurate location of the fault by comparing the transient RMS value of the upstream and the downstream of the fault point, even though the Petersen coil is switched in.