Optimal Overcurrent relays coordination using particle-swarm-optimization algorithm

For optimal co-ordination of Overcurrent (OC) relays, linear programming techniques such as simplex, two-phase simplex and dual simplex are used. Another way of optimal coordination program is using artificial intelligent system such as particle swarm optimization (PSO) algorithm. In this paper a new approach will be used for optimal coordination of OC relays based on particle swarm algorithm. In this work we take into account both time setting multiplier (TSM) and plug setting multiplier (PSM) of OC relays in optimization procedure. Most OC relays accept only discrete values as TSM and PSM, and you should change your final answers to discrete form and this may corrupt the optimization. In this paper the act of quantizing the answers is taken into account as a part of optimization procedure, so the outputs are optimized discrete TSM's and PSM's. In other words the novelty of the paper is taking into account the PSM in addition to TSM to handle miscoordination problems both for continues and discrete TSM and PSM. The results obtained are quite encouraging and will be useful as an effective tool for coordination OC relays.