An adaptive protection scheme for distributed systems with distributed generation

An adaptive protection scheme using digital relays with a communication network is proposed for the protection of the distributed systems. The impact of distributed generators on protection coordination is first discussed. Then, an adaptive protection scheme is proposed for distributed systems with distributed generation (DG). Simulated results on an actual distribution system show that the proposed approach can perform adaptive primary and backup protection functions under both balanced and unbalanced fault conditions. Also, the proposed approach is adaptive to the fault types as well as capacities of DG. Compared with the traditional current protection scheme, the primary and backup protection regions have been extended considerably.