A Novel Approach to Provide Relay Coordination in Distribution Power Systems with Multiple Reclosers

Electricity customers are increasingly sensitive to electric power interruptions and high reliability has become a growing expectation. Due to this increased attention in electric power distribution system reliability, more protection devices are being installed and significant investment is made to help improve grid reliability. The increased usage of protective devices in distribution systems makes coordination among the protective devices challenging. In many cases, proper coordination cannot be achieved with traditional time-overcurrent schemes. In addition to the coordination problem, the traditional approach might experience longer clearance time intervals. In order to achieve feasible coordination in a radial distribution system with multiple reclosers, a new approach is proposed. In this method, distance relays are applied along with overcurrent relays and reclosers to provide the expected proper coordination. The paper includes detailed case study that represents the performance of the proposed scheme in a multi-recloser distribution system.