Optimization of battery energy storage system (BESS) for enhanced frequency regulations in power grid

Abstract

The increasing integration of renewable energy sources into modern power systems presents new challenges in maintaining grid stability, particularly in terms of frequency regulation under high active power demand conditions. This thesis investigates the effectiveness of Battery Energy Storage Systems (BESS) in enhancing frequency stability in power systems during such critical events. A modified IEEE 9-Bus system was used as the simulation environment, in which one of the traditional synchronous generators was replaced with a 30 MVA BESS unit connected at a 1000 V low-voltage bus. Simulations was carried out using DIgSILENT PowerFactory 15.1 to analyze the system’s frequency response to load disturbances both with and without BESS integration. Key metrics such as frequency nadir and Rate of Change of Frequency (RoCoF) were evaluated to quantify the performance impact of the BESS. Results show that the presence of BESS significantly improves the system’s ability to withstand frequency deviations by providing rapid active power support. This study highlights the critical role of BESS in supporting frequency regulation in low-inertia, renewable-rich power systems and offers insights into optimal energy storage integration strategies.