OPTIMAL PLACEMENT OF SOLAR DISTRIBUTED GENERATION FOR RELIABILITY IMPROVEMENT IN DISTRIBUTION NETWORKS USING WHALE OPTIMIZATION ALGORITHM (CASE STUDY: BISHOFTU SUBSTATION 2

Abstract

The power distribution system in Bishoftu, Ethiopia, is faced with significant reliability challenges, including frequent interruptions, overloading, and poor performance that fall below national standards. These issues are caused by increasing load demand and inefficient system management. To address these challenges, the integration of solar-based distributed generation (DG) was investigated as a solution to enhance the reliability of the Bishoftu Substation. The K9 feeder, which exhibits the most severe reliability issues, was selected for this study, with initial reliability indices of SAIFI = 363.5 interruptions/customer/year and SAIDI = 803.14 hours/customer/year, far exceeding the national standards of SAIFI = 20 and SAIDI = 25. The Whale Optimization Algorithm (WOA) was utilized in MATLAB to determine the optimal sizing and placement of DG units, with the aim of minimizing SAIFI and SAIDI. Solar energy was identified as the most viable DG option based on local solar irradiance data. Significant improvements were demonstrated through optimization, with SAIFI and SAIDI reduced by up to 86% and 87% respectively, achieving values of SAIFI = 50.89 interruptions/customer/year and SAIDI = 104.4 hours/customer/year. An economic analysis was also conducted to evaluate the initial investment and life cycle costs, ensuring the feasibility of the proposed solution. It was concluded that the integration of optimally sized and placed solar DG units can drastically improve system reliability, reduce interruptions.