Network-based Adaptive Protection Strategy for Feeders with Distributed Generations

Various kinds of distributed generations (DGs) are being increasingly connected on the distribution systems and computer network-based controls are introduced to assist the system operations. This paper proposes a new network-based adaptive strategy for protection of distribution-system feeders connected with DGs. The proposed strategy provides an intelligent network-enabled protection for feeders and overcomes the DGs-imposed technical challenges such as increase of fault current, change of prescribed fault flow paths, sympathetic tripping, unintentional islanding operation, continuous non- interruptible fault current, etc., as well as non-DG-caused problems such as undetected high-impedance ground faults. This paper illustrates effective real-time determination of correct protection operations for feeders with dispersed DG-connections against faults and surges resulting from lightning, switching, equipment short-circuit, etc. Four typical case studies of the proposed network-enabled adaptive protection strategy for feeders in the distribution system connected with DGs are provided in the paper.