Fault identification of transmission line using the union back-up information in regional-area

A back-up protection scheme based on the union back-up protection information for a transmission network is described in the paper. The scheme, referred to as the Back-up Protection Decision System (RBDS), is implemented by using three relevant matrixes SF, TF and DE, and three action factors α, β and γ. The RBDS provides optimal fault clearance for faults located anywhere on the protected network. To achieve an optimal response, the RBDS needs to know the topology of the network and the operating information of back-up relays. Based on this information, the Back-up Protection Decision System will try to identify the line which contains a fault. The relaying protection N-1 operation statuses are analyzed. The results of case studies show that this scheme based on the union back-up protection information is simple and convenient for fault determination, and the results are exact against N-1 operation statuses that can improve the performance of the back-up protection system.