International Journal of Advances in Engineering & Technology, July 2012. ©IJAET ISSN: 2231-1963 26 Vol. 4, Issue 1, pp. 26-41 EFFICIENCY IMPROVEMENT OF NIGERIA 330KV NETWORK USING FLEXIBLE ALTERNATING CURRENT TRANSMISSION SYSTEM (FACTS) DEVICES Omorogiuwa Eseosa 1 , Friday Osasere Odiase 2 1 Electrical/Electronic Engineering, Faculty of Engineering, University of Port Harcourt, Rivers State, Nigeria 2 Electrical/Electronic Engineering, Faculty of Engineering University of Benin, Edo State, Nigeria ABSTRACT This work studied the impact of different FACTS devices (UPFC, TCSC and STATCOM) on voltage improvement and transmission loss reduction in the Nigeria 330KV transmission line network and GA approach for loss optimization. This network consist of 9 generating stations, 28 buses and 29 transmission lines was modeled and simulated using ETAP 4.0 and Matlab Version 7.5.Power losses without FACTS device are 62.90MW and 95.80MVar and weak buses per unit values are: Gombe (0.8909pu), Jos (0.9118pu), Kaduna (0.9178pu), Kano (0.9031) and New Haven(0.9287pu).Incorporating TCSC on the weak lines, an improved per unit bus values ranging from 0.9872pu-0.9997pu was obtained as well as loss reduction of (44.3MW and 78.30MVAR). Incorporating UPFC improved the per unit values within the range of 0.9768pu-0.9978pu. STATCOM gave values between 0.9741pu-1.013pu and reduced line losses to51.8MW and 85.60MVAR.Comparing among the three FACTS devices, UPFC gave a better loss reduction of 48.64% and 27.14%. KEYWORDS: TSCS, STATCOM, UPFC, GA, ETAP 4.0, MATLAB 7.5 I. INTRODUCTION Nigeria electric power system is undergoing changes as a result of constant power demand increase, thus stretching it beyond their stability and thermal limit. This drastically affects the power quality delivered. Transmission systems should be flexible to respond to generation and load patterns. Solving the problem of increasing power demand is either by building more generating and transmission facilities which is not very economical or environmentally friendly or the use of Flexible Alternating Current Transmission System (FACTS) Devices. FACTS device ensure effective utilization of existing equipment. Comparison of the conventional methods of control (capacitors, reactors, phase shifting transformers etc.) and FACTS devices showed that they are less expensive, but their dynamic behavior and control of current, phase voltage and angles, line impedance are less optimal (1,7,8). The Institute of Electrical-Electronic Engineering (IEEE) defined FACTS as ‘’ power electronic based system and other static equipment that provide control of one or more AC transmission system parameters to enhance controllability and increase power transfer capability’’ (1).Benefits of FACTS device are in two folds: Capable of increasing power transfer over transmission lines and can make their power transfers fully controllable (2, 3, and 4).The focus of this paper is to study how different FACTS devices (UPFC, TCSC and STATCOM) reduce power losses in the Nigeria existing 330KV network. The results obtained are presented.