coordination of directional overcurrent relay characteristics using the pso optimization algorithm

This article discusses about coordination of directional overcurrent relays (docrs) in the power system transmission lines. in these relays, 4 characteristics are used as variables to calculate coordination between of them. these 4 variables include ps, tms, a and b, which are used to obtain optimal coordination between relays. in this article, to obtain optimal coordination, two fault locations are considered. one of them is near the relay (at the 10%-line beginning) and another is fault far from the relay (at the 90%-line end). the problem of coordination of relays is solved and optimized using the pso optimization algorithm. the proposed method has been tested in the standard distribution 6-buse ieee system, and its results are stated. the results of the pso optimization method that was obtained have been compared with traditional methods such as ga-nlp. comparing the results of this method with the traditional methods presented in the other articles, found that the presented method obtains more optimal results than other traditional methods. since the proposed method minimizes the operation time of docrs relays. this method is a reliable and effective method for calculating coordination between relays.