Solving Multi-objective Optimal Power Flow Using Modified GA and PSO Based on Hybrid Algorithm

Document Type : Research paper


1 Depatment of Electrical Engineering, Karaj Branch,Islamic Azad University

2 Faculty of Electrical and Biomedical Engineering Qazvin Branch, Islamic Azad University

3 Department of Electrical Engineering, Karaj branch, Islamic Azad University,


The Optimal Power Flow (OPF) is one of the most important issues in the power systems. Due to the complexity and discontinuity of some parameters of power systems, the classic mathematical methods are not proper for this problem. In this paper, the objective function of OPF is formulated to minimize the power losses of transmission grid and the cost of energy generation and improve the voltage stability and voltage profile, considering environmental issues. Therefore, the OPF problem is a nonlinear optimization problem consisting of continuous and discontinuous variables. To solve it, Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and a new hybrid algorithm combining modified Particle Swarm Optimization (PSO) and Genetic algorithm (GA) methods are proposed. In this method, each of the algorithms is performed in its procedure and generates the primary population; then, the populations are ordered and from among them, populations with the highest propriety function are selected. The first population that guesses will enter the two algorithms’ procedures for generating the new population. Note that the inputs of the two algorithms are the same; then, generates a new population. Now, there are three groups of populations: one created by modified GA, one created by modified PSO, and the other is the first initial population, and then sorted with the described sorting method.


Main Subjects

Volume 5, Issue 1
June 2017
Pages 51-60
  • Receive Date: 10 July 2016
  • Revise Date: 10 August 2016
  • Accept Date: 20 June 2017
  • First Publish Date: 20 June 2017