Table of Contents
ISRN Power Engineering
Volume 2014, Article ID 869617, 10 pages
Research Article

Optimal Overcurrent Relay Coordination Using Optimized Objective Function

1Electrical Engineering Department, University of Zanjan, Zanjan 45371-38791, Iran
2Zanjan Regional Electric Company, Zanjan 33685-45137, Iran

Received 8 January 2014; Accepted 9 March 2014; Published 3 April 2014

Academic Editors: L. D. S. Coelho, B. Li, and H. Torkaman

Copyright © 2014 Seyed Hadi Mousavi Motlagh and Kazem Mazlumi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A novel strategy for directional overcurrent relays (DOCRs) coordination is proposed. In the proposed method, the objective function is improved during the optimization process and objective function coefficients are changed in optimization problem. The proposed objective function is more flexible than the old objective functions because various coefficients of objective function are set by optimization algorithm. The optimization problem is solved using hybrid genetic algorithm and particle swarm optimization algorithm (HGAPSOA). This method is applied to 6-bus and 30-bus sample networks.