EFFECTS OF FACTS DEVICES (TCSC, UPFC) ON NORMAL MODE OPERATION OF 330kV TRANSMISSION NETWORK IN NIGERIA

Abstract

This study is aimed at improving the steady state mode transmission capacity of 28 bus system of Nigeria 330 kV transmission network by investigating the effects of the installation of FACTS devices. Bus and Line data of the selected transmission network were collected from national control center. Newton Raphson Algorithm was used to carry out the load flow analysis of the network without the incorporation of FACTS device in order to appraise the existing load flow. The power injection models of the FACTS devices were presented. The specific location of the FACTS devices for optimal power flow was determined by considering the sensitivity of the lines to reactive power loss. The load flow analysis was carried out with the incorporation of the FACTS devices at the optimal location considering the thermal limit constraint, and the economic efficacy of the FACTS devices were evaluated. The FACTS considered in the study are Thyristor Controlled Series Capacitance (TCSC) and Unified Power Flow Controller (UPFC). Newton Raphson algorithm was used to carry out the load flow analysis of the selected transmission network, with FACTS devices inline with the constraint. The algorithm was implemented in MATLAB. The results showed that incorporation of TCSC brought about increase in the real power transmitted by 15.39MW while UPFC brought about transmission capacity increase by 5.31MW. Furthermore, the economic implication of the FACTS devices were considered, and the pay back period of the FACTS were evaluated. The result showed that TCSC has a pay back period of 6 months while UPFC has a pay back of 8 months. The loading coefficients of the lines were calculated to check if the constraint was kept. This showed that no line was loaded more than 0.6 of its thermal limit. It was concluded that the selected FACTS devices could be applied to improve transmission capability of the network, and the respective optimal location of the selected devices in the existing Nigerian transmission network is Osogbo Benin line for TCSC and Onitsha New Haven line for UPFC.