New trends in power system includes the optimal placement of Flexible AC transmission System (FACTS) devices to improve the performance of the system by managing the power by managing the load. A meta heuristic method is proposed for the optimal placement and sizing of FACTS devices, namely the Thyristor-Controlled Series Compensators (TCSCs), Shunt VARs Compensators (SVCs), and Unified Power Flows Controllers (UPFCs). To find the optimal locations of these devices in a network, weak buses and lines are determined through the line sensitivity index, Then, Hybrid GA-PSO is employed not only to find an ideal rating for these devices but also the optimal coordination of SVC, TCSC, and UPFC with the reactive power sources already present in the network (tap settings of transformers and reactive power from generators). The Line sensitivity index (LSI) in which three scenarios are considered with line outage and also with different loading conditions, to calculate the power loss. The objective here is the minimization voltage deviation and reduction of power losses in the network to improve the system performance. The methods are applied to the IEEE 14 bus test system.