Coordination Improvement of Directional Overcurrent Relays in a Microgrid Using Modified Particle Swarm Optimization Algorithm

摘要

An accurate and fast relaying scheme is of high importance in a radial distribution network and it becomes complex to realize in a multi-sourced distribution network with Distribution Generators (DGs). The study of the existing relay coordination of the 33 kV Idu Industrial Park Distribution Network, Abuja and its improvement opportunities is presented in this research in other to guarantee safety of operation and protection of the distribution network against the effects of faults. A proposed 6 Bus Idu microgrid based on planned network expansion program was modeled using DIgSILENT PowerFactory software. Load Flow and Fault Analyses were performed on the modeled network to determine appropriate Directional Overcurrent Relay (DOCR) settings and a Modified Particle Swarm Optimization Algorithm (MPSO) in MATLAB environment was used to optimize the Time Dial (TD) and Pickup (PU) settings of the DOCRs. The modification adopted was to keep the solution space within boundaries so as to achieve fast convergence. The sum of the operating time of the radial feeder was found to be 3.68 s while that of the proposed 6 Bus Microgrid with 14 DOCRs and 3 DGs was found to be 3.7903s which was quite fast and satisfactory after validation on the modeled microgrid.