A New Hybrid Particle Swarm Optimization for Optimal Coordination of Over Current Relay

Abstract

Directional over current relays (DOCRs)<br><br>coordination problem is a nonlinear and nonconvex problem<br><br>which has many constraints. Optimal coordination of over<br><br>current relays has been usually solved using linear and nonlinear<br><br>programming. Also genetic algorithm and particle swarm<br><br>optimization methods are used to fined the optimal solution of the<br><br>problem. In this paper a new hybrid approach will be used for<br><br>optimal coordination of over current relays. In this work, both<br><br>time setting multiplier (TMS) and current setting (IP) are taken<br><br>into account in the optimization procedure. The former is<br><br>consider as a continues parameter and the later is assumed to be<br><br>discrete parameter. The novelty of this paper is that quantizing IP<br><br>parameter is taken into account as a part of optimization<br><br>producer in the particle swarm optimization iterations. After<br><br>that, we can calculate the optimum TMS with linear<br><br>programming at the end of each iteration of PSO optimization<br><br>algorithm. To increase the accuracy of proposed algorithm, first<br><br>particle positions of swarms was calculated with linear<br><br>approaches. Both near-end and far-end faults are taken into<br><br>account in the constraint of the optimal coordination problem<br><br>and the results are compared with the other methods. The<br><br>obtained results are quite encouraging and will be useful as an<br><br>effective method for coordination of over current relays.