Abstract
In this paper, a multiobjective evolutionary algorithm (MOEA) to solve optimal reactive power (VAR) dispatch problem with flexible AC transmission system (FACTS) devices is presented. This nonlinear multiobjective problem (MOP) consists to minimize simultaneously real power loss in transmission lines and voltage deviation at load buses, by tuning parameters and location of FACTS. The constraints of this MOP are divided to equality constraints represented by load flow equations and inequality constraints such as, generation VAR sources and security limits at load buses. an unified power flow controller (UPFC) is considered. The design problem is tested on the IEEE 6-bus system.