This paper proposes a chaotic biogeography based optimization (CBBO) for solving optimal reactive power dispatch (ORPD) problem. Based on biogeography based optimization (BBO) theory proposed by Dan Simon in 2008. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 18, SOÁ K6- 2015 Optimal reactive power dispatch by chaotic biogeography based optimization Truong Xuan Quy Vo Ngoc Dieu Ho Chi Minh city University of Technology, VNU-HCM, Vietnam (Manuscript Received on July 15, 2015, Manuscript Revised August 30, 2015) ABSTRACT This paper proposes a chaotic biogeography based optimization (CBBO) for solving optimal reactive power dispatch (ORPD) problem. Based on biogeography based optimization (BBO) theory proposed by Dan Simon in 2008, a new artificial intelligence with full models and equations have been used to achieve the best solution for objective function of ORPD such as total power loss, voltage deviation and voltage stability index while satisying various constraints of power balance, voltage limits, transformers tap changer limits and switchable capacitor bank limits. The BBO has been enhanced its search ability by adding chaotic theory. Therefore, the proposed CBBO can obtain better solutiong quality than BBO for optimization problems. The proposed method has been tested on the IEEE-30 and IEEE-118 bus systems and the obtained results have been verified with other methods. The result comparison has indicated that the CBBO can be a promise method for dealing the ORPD problem Keywords: Optimal Reactive Power Dispatch, Biogeography Based Optimization, Chaos Theory, Power loss, Voltage Deviation, Voltage Stability Index 1. INTRODUCTION The main objective of optimal reactive power dispatch (ORPD) [1] in electrical power system is to minimize the objective function via the optimal adjustment of the power system control variables, while at the same time satisfying various equality and inequality constraints. Some objective functions in ORPD to evaluate the quality of power system is real power loss, voltage deviation at load buses [2], voltage stability index [3]. The equality constraints are the power flow balance equations, while the inequality constraints are the limits on the
