Voltage Stability Improvement with finest position of UPFC using GA &PSO

Power system is a largely inter connected network, due to this interconnection some of the lines may getover loaded and voltage collapse will occur , hence these lines are called weak lines, this causes seriousvoltage instability at the particular lines of the power system. The improvement of stability will achieve bycontrolling the reactive power flow. The Flexible Alternating Current Transmission Systems (FACTS) deviceshave been proposed to effectively controlling the power flow in the lines and to regulate the bus voltages inelectrical power systems, resulting in an increased power transfer capability, low system losses andimproved stability.In FACTS devices the Unified Power Flow Controller (UPFC) is one of the most promising device for powerflow control. It can either simultaneously or selectively control both real and reactive flow and bus voltage.UPFC is a combination of shunt and series compensating devices. Optimal location of UPFC is determinedbased on Voltage Stability Index (VSI). GA and PSO techniques are used to set the parameters of UPFC [6].The objective function formulated here is fitness function, which has to be maximized for net saving. Theresults obtained using PSO on IEEE 14 Bus is compared with that of results obtained using GA, to show thevalidity of the proposed techniques and for comparison purposes