Abstract—This paper presents an improved genetic algorithm for Optimal Reactive Power Dispatch (ORPD) to minimize active power loss and improve the voltage profile of power systems. The goal of ORPD is to determine generator bus voltages, transformer tap positions and switchable shunt capacitor banks when satisfying problem constraints such as bus voltage magnitude limits, generator reactive capabilities and the size of shunt capacitors. It is obviously a large-scale nonlinear optimization problem with both continuous and discrete control variables. While Genetic Algorithm is known to reach the global optimal solution, the main difficulty of application of GAs is their premature convergence. In order to improve the search ability of GA this paper proposes a new coding method for this problem in which each chromosome is divided into two sections, one for continuous variables and another for discrete ones. Also appropriate specific crossover and mutation operators that can work with both real and binary genes are defined. The proposed method is tested on IEEE 30-bus and 14-bus systems and results are compared with those of Simple binary-coded and real-coded genetic algorithms. Test results demonstrate the effectiveness of proposed method in finding the global optimal solution within a reasonable computing time.

Index Terms—Improved genetic algorithm, loss reduction, optimal reactive power dispatch, voltage profile improvement.

Dawood Talebi Khanmiri is with Islamic Azad University- Bonab Branch, Bonab, Iran (e-mail: dtalebi@gmail.com).
Nasibeh Nasiri is with Information Technology and Computer Engineering Department, Azarbaijan University of Tarbiat Moallem(email:nasiri@azaruniv.edu).
Taher Abedinzadeh is with Islamic Azad University- Shabestar Branch, Shabestar, Iran (e-mail: Taherabedinzade@Yahoo.com).

Cite: Dawood Talebi Khanmiri, Nasibeh Nasiri, and Taher Abedinzadeh, "Optimal Reactive Power Dispatch Using an Improved Genetic Algorithm," International Journal of Computer and Electrical Engineering vol. 4, no. 4, pp. 463-466, 2012.