Design and simulation of an automatic generation control system for real time power balance of Uganda's power grid

Abstract

This project focused on the design and simulation of an Automatic Generation Control (AGC) system to improve real-time power balance on Uganda’s electricity grid. The study addressed critical challenges in manual frequency regulation and tie-line management by developing an optimized control system for Uganda’s hydro-dominated generation mix, including major plants like Isimba Hydro Power Plant (HPP), Karuma HPP, Nalubaale HPP, and Bujagali Energy Limited. The research also incorporated Kenya-Uganda tie-line power exchanges and the integration of intermittent renewable energy sources like solar plants to reflect actual grid conditions. Using MATLAB/Simulink modeling, the AGC system was tested under five operational scenarios to evaluate its performance. Under normal conditions, the system maintained grid frequency within ±1% Hz of the nominal 50 Hz through efficient economic dispatch. During the simulated 100 MW load fluctuations, the AGC system demonstrated rapid stabilization, preventing potential blackouts and equipment damage. The system also effectively managed an 8 MW tie-line backflow from Kenya by automatically adjusting generation outputs. Additionally, it compensated for 50 MW mini-plants intermittency by dynamically ramping hydropower generation. A critical test involved a 45.8 MW generator trip at Isimba HPP, where the AGC responded within seconds by deploying spinning reserves, showcasing its reliability during sudden outages. The results highlighted the AGC’s significant advantages, including a frequency stabilization within a required tolerance and a faster response time compared to manual control during disturbances. The system also optimized generation costs, achieving savings during peak demand periods, while ensuring compliance with Uganda’s scheduled 50 MW power exports to Kenya. These findings underscore the AGC’s potential to enhance grid stability, reduce operational costs, and support Uganda’s participation in the East African Power Pool (EAPP). In conclusion, the simulation of an AGC system for Uganda’s grid improved stability, efficiency, and reliability. The study recommends phased implementation of AGC to facilitate renewable energy integration and improve regional power exchange capabilities. Future research should explore congestion management and assess AGC compatibility with microgrid applications.