The development of optimization techniques in power system is to determine the sizing of Flexible AC Transmission System (FACTS) devices such as Unified Power Flow Series Compensator (UPFC) controller in improving the voltage stability and bus voltage margin. An attempt is made to modify the Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC) with Hybrid-Genetic Algorithm (H-GA) for determination of sizing of the device. Fast Voltage Stability Index (FVSI) is used to identify the location of the device to be connected. The proposed methods are implemented in IEEE 30 Bus system and its results are tabulated for each technique.