Unified power flow controller based reactive power dispatch using oppositional krill herd algorithm

• OKHA algorithm applied to UPFC based ORPD problem is proposed.
• The proposed method is implemented on IEEE 57-bus and IEEE 118-bus test systems.
• UPFC is optimally placed to solve single and multi-objective ORPD problems.
• The effectiveness of OKHA is compared with BBO, DE and KHA algorithms.

In power system, minimizing the power loss in the transmission lines and/or minimizing the voltage deviation at the load buses by controlling the reactive power is referred as optimal reactive power dispatch (ORPD). This paper presents an improved evolutionary algorithm based on oppositional krill herd algorithm (OKHA) for obtaining optimal steady-state performance of power systems. This article also proposes the effect of UPFC location in steady-state analysis and to demonstrate the capabilities of UPFC in controlling active and reactive power flow within any electrical network. To verify the effectiveness of KHA and OKHA, two different single objective functions such as minimization of real power losses and improvement of voltage profile and a multi-objective function that simultaneously minimizes transmission loss and voltage deviation have been studied through standard IEEE 57-bus and 118-bus test systems and their results have been reported. The study results show that the proposed KHA and OKHA approaches are feasible and efficient.