Firefly algorithm based multi-objective optimization using OUPFC in a power system

Firefly Algorithm (FA) is employed to optimize the control variables of a hybrid FACTS device known as optimal unified power flow controller (OUPFC) for simultaneous optimization of real power loss (RPL) and voltage stability limit (VSL) of a system. Mathematically, this problem is a constrained multi-objective optimization problem having an objective function of RPL and VSL. OUPFC device is a combination of phase shifting transformer (PST) and a miniature unified power flow controller (UPFC). OUPFC parameters such as OUPFC location, UPFC series injected voltage magnitude and phase angle, and PST phase angle are treated as control variables in the problem formulation. The effectiveness of the proposed FA have been verified on IEEE 14bus and New England 39 bus test systems. The results of the proposed FA with OUPFC device have been compared with the results of the FA with UPFC, as available in the literature. The comparison results show the robustness and efficiency of the method.