A new approach for optimal capacitor placement and sizing in unbalanced distorted distribution systems using hybrid honey bee colony algorithm

Abstract

Despite increase in application of distributed generations (DGs) in power systems in recent years and their positive impacts, DG’s are likely to amplify the harmonic distortion level. Moreover, placing shunt capacitors in distribution systems without considering harmonics may increase harmonic pollution of distribution systems due to imposed resonance between shunt capacitors and inductive elements of the power system. In addition, distribution systems are inherently unbalanced due to their different loads. Hence, in case shunt capacitors are not optimally placed, system unbalance and harmonic level may increase. In this article, an attempt was made to achieve optimal capacitor placement using a hybrid honey bee colony (HHBC) optimization algorithm aiming to minimize power system losses and unbalances and maximize the ensuing net saving while maintaining voltage and total harmonic distortion (THD) of buses in an acceptable range according to IEEE standards. To include the presence of harmonics, the method was integrated with a three-phase harmonic power flow algorithm. Having defined a special fitness function, effects of power system unbalances and harmonics, were taken into account. The proposed method were tested on two unbalanced distorted radial distribution test systems (including an IEEE 25-bus and a modified IEEE 37-bus) with and without the presence of DGs. Simulation results have been compared with those from standard artificial bee colony (ABC) algorithm and other such artificial intelligence techniques as genetic algorithm (GA), particle swarm optimization (PSO), and imperialist competitive algorithm (ICA). These results suggest that the proposed methodology offer acceptable numerical accuracy, robustness and efficiency and demonstrate that the proposed approach may outperform other artificial intelligence techniques.