VOLTAGE PROFILE IMPROVEMENT AND LOSS MINIMIZATION USING UNIFIED POWER FLOW CONTROLLER WITH FUZZY LOGIC CONTROLLER IN TRANSMISSION LINE (CASE STUDY: GILGEL GIBE III TO WOLAYTA SODO SUBSTATION II 400 kV LINE)

Abstract

An essential function of the power transmission network is to transfer electrical power from power plants to households, companies, etc. This thesis primarily examines the 400KV transmission lines that connect Gilgel Gibe III to Wolayta Sodo II. The demand for electric power is skyrocketing everywhere, but there are few resources and environmental regulations that can accommodate the expansion of power generation and transmission systems. As a result, certain transmission lines are experiencing heavy loads, and issues with system losses and performance are emerging as factors that limit the transfer of power. Power losses and increased voltage deviation occur when the power transmission system operates with heavily loaded lines. The power transmission system is under stress due to an unplanned increase in load variation, which could cause a cascade trip. As a result, power networks can be kept from running at full capacity by closely monitoring load variation. Specialized schemes, comprising reactive power compensation, the installation of FACTs devices (UPFC, STATCOM, etc.), and capacitor placement, can be employed to deal with this phenomenon. The use of a unified power flow controller (UPFC) based on a fuzzy logic controller (FLC) to minimize losses and improve voltage profile is presented in this thesis. Finding the best location for UPFC requires first identifying the weak buses (Bus 2 and Bus 3 in this case) in the system using the Newton- Raphson load flow analysis method. Without the implementation of a UPFC, the power losses in the tested system were 22.91 MW, while with PI, they were 4.85 MW. The system that integrated UPFC-based fuzzy logic achieved the lowest power loss of 0.09 MW. Following the installation of the UPFC, which has a rating of 27.37MVAR, the voltage profile of every bus improved to 1P.u. The annual payback period determined that using a unified power flow controller resulted in an annual active and reactive energy loss of 200.691 Gwh and 0.7884 Gwh, costing 110.380 and 0.43362 million birr, respectively, with an annual savings of roughly 109.94638 million ETB. It is possible to recoup the initial investment within 2.4990796782 years and Four month. In terms of controlling power flow, voltage profile improvement, and lowering power loss in a transmission line, it has been seen from simulation results that the proposed FLC-based UPFC has better performance compared to conventional PI controlle