Dual-Setting Directional Overcurrent Relays for Protecting Automated Distribution Networks

This paper elaborates a new protection scheme based on dual-setting DOCRs for automated distribution networks. In this course, the reduction in relays operation time saturates as the number of these relays increases. Thus, optimal deployment of dual-setting DOCRs should be specified in an efficient manner. To do so, a multiobjective optimization approach is established, which compromises the reduction of total operation time and the number of dual-setting DOCRs. Coordination constraints are accommodated and nonstandard inverse-time characteristics are established to intensify flexibility of the proposed strategy. The proposed model lies within a nonlinear programming fashion, which is tackled by particle swarm optimization. Moreover, the augmented ε-constraint approach is utilized to reach the Pareto-optimal solutions following which the fuzzy decision making process determines the best compromised solution. Detailed simulation studies are carried out to interrogate performance of the proposed approach.