Recloser-fuse coordination protection for distributed generation systems: Methodology and priorities for optimal disconnections

This study investigates a recloser-fuse coordination protection methodology for distributed generation systems. The technique identifies critical margins for proper recloser-fuse coordination and monitors distribution line ratings in real-time. In case of violations, only distributed generators attributed to effectively increasing short-circuit level are disconnected from the grid by gate turn-off thyristors. Therefore, fault current is reduced to a satisfactory level, restoring the coordination between reclosers and fuses in radial distribution feeders. Besides, the methodology enables new distributed energy resources to be connected to the grid, even during fault occurrences, if main short-circuit contributors are disconnected and a fault threshold level is maintained. Priorities for optimal disconnections are presented and allow utilities to achieve greater supply security by adapting the proposed protection system to feeder´s particularities. Finally, this paper reviews on-going activities that are being performed for the development of the proposed approach.