Earth Fault Location for Non-Directly Grounded Distribution Networks

When a single-phase ground fault occurs in a non-directly grounded system, the initial objective is to identify the faulty section. However, if the fault extends over a considerable length, manually locating the fault position becomes a complex and time-consuming process. To overcome this critical challenge of determining the fault location within the identified section, we propose a low-current grounding fault location technology that utilizes the zero-sequence voltage distribution features provided by the pre-existing devices of the distribution automation system. By analyzing the distribution features of zero-sequence current and voltage following a fault occurrence, we can derive the zero-sequence voltage fitting functions of the fault line. With these functions, we can determine the fault point by identifying the intersection of the upstream and downstream sections' zero-sequence voltage fitting functions. The simulation and field results have demonstrated that this method is both economically feasible and highly precise in fault location, provided that the correct fault section is identified.