Optimal coordination of Overcurrent and Distance Relays by a New Particle Swarm Optimization Method

Abstract — Nowadays, overcurrent relays play more important impression role on protection of power systems and the existence of distance relay accost of overcurrent relay causes protection increment and also complicating coordination between these relays. In recent years, intelligent optimal methods are being used more in comparison of mathematic optimal methods because of advantages-such as solving non linear problems; up speed; avoid using complicated mathematic problems, etc. For coordination of relays, at first, with detection of critical points, short circuit is done in those locations, then problem constraints are generated and the problem is solved by new method. In this paper, new method- named LP-PSO- has been suggested. This model is a combination of Linear Programming and Particle Swarm Optimization. The aim of LP (Linear Programming) is to decrease object function in any way that there are some constraints. Executed studies and comparison of results with other optimal method –Genetic algorithm-presents that coordination of relays has been done favorable. Keywords—Overcurrent and Distance relay, Optima