A Unit Protection Scheme for IIDGs in Distribution Systems Using Superimposed Components and μPMU Data

Inverter interfaced distribution generating sources (IIDGs), incorporated in the distribution system impose various operational and protection challenges. The dynamic fault characteristics and bi-directional power flow along with high impedance faults (HIFs) cause problems in the conventional distribution networks and demand some improved protection strategies to distinguish out-of-section faults from internal faults. Further, it should not be sensitive to the non-fault conditions. This work presents a unit protection scheme based on the computation of differential components of the superimposed voltage and current signals at the location of the relay. Further, to identify the faulty feeder, this method requires relaying information about other feeders through micro-phasor measurement units (μPMUs). The feasibility of the proposed method is tested by simulating two feeder distribution networks. Results show the efficacy of the proposed method.