Battery Energy Storage System Supporting Frequency Regulation of Power System with High Renewable Penetration

The utilization of renewable energy (RE) has increased worldwide because it is one of the effective ways to minimize greenhouse gases. The power outputs of photovoltaic (PV) and wind farms depend on weather conditions. High penetration of intermittent renewable energy (IRE) will put pressure on frequency regulation, and frequency fluctuation will increase because IRE does not participate in frequency regulation. This study evaluated the role of battery energy storage systems (BESS) in the frequency regulation of a grid with large-scale IRE. The simulations were conducted in the MATLAB–Simulink environment, taking into consideration the operating conditions of the Republic of South Africa (RSA) power system, such as frequency deviation limits. Eskom’s (the RSA utility company) policy requires its operators to keep the system frequency between 49.85 Hz and 50.15 Hz 95% of the time. The BESS was integrated into the load frequency control (LFC) model to assist with frequency regulation and maintain the frequency between 49.85 Hz and 50.15 Hz.