Symmetrical and Fault Components Based Pilot Protection for Distribution Network with T-connected Inverter Interfaced Distributed Generations

Due to the advantages of cleanliness, efficiency and flexibility, inverter interfaced distributed generators (IIDG) have been widely used in distribution network (DN). The number of T-connected IIDGs in DN increases quickly because of the characteristics of flexible access location and low investment cost. However, the access to flexible T-connected IIDG's electrical information is difficult, which means the new pilot protection method is needed for situation without communication to T-connected IIDGs. Based on symmetrical components and fault components, this paper proposes a new pilot protection criterion, which uses the specific value of integrated sequence current and the phase difference of fault negative sequence current, for DN with T-connected IIDGs. Compared with traditional pilot protection, the criterion proposed in this paper gets rid of the need for IIDG's electrical information. The simulation results verify the sensitivity and reliability of the proposed pilot protection criterion in this paper.