Directional pilot protection method for distribution grid with DG

With the integration of DG, the power flow direction of distribution grid may be changed from single to bidirectional. In this situation, the conventional current protection scheme faces the extreme challenge, even does not meet the requirement of distribution grid with DG. Therefore, this paper proposes a directional pilot protection method to protect the upstream line of DG. Using the fault components of voltage and current, an energy function is constructed. Through analyzing the characteristics of energy function, the fault direction can be easily identified, further the faulted section of line is also determined. Simulation results show the proposed method is valid and feasible.