Energy storage system modeling and control for power system frequency regulation

• Main Author: Li, Shan
• Other Authors: Xu Yan
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2025
• Subjects: Engineering; Inertia response (BESS); Zonal inertia; Frequency security
• Online Access: https://hdl.handle.net/10356/182913
• Institution: Nanyang Technological University

The increasing penetration of renewable energy sources in interconnected power systems has resulted in a decrease and uneven distribution of system inertia. Unlike conventional generators, renewable energy generators do not naturally provide inertial response. Low inertia can result in a high initial rate of change of frequency (RoCoF) and low frequency nadir during contingencies, such as the tripping of generators or interconnectors. Energy storage systems (ESSs) have emerged as a solution to provide fast frequency response (FFR) and support frequency regulation, thereby maintaining a constant level of inertia in each area of the power system. However, the inertial response capability of ESSs varies as their operating points change in real-time when ESSs participate in primary frequency regulation, automatic generation control (AGC), and economic dispatch simultaneously. This dissertation proposes a zonal inertia-constrained Automatic Generation Control (AGC) strategy that optimizes ESS operating points in real time, which maintains sufficient inertia in each region and improves interconnected system frequency security. The proposed method is validated through simulations conducted on a modified IEEE 30- bus system under different renewable energy penetrations and different load scenarios. The performance of the proposed method is compared with the fixed factor AGC allocation method. The simulation results demonstrate that the proposed method effectively improves system frequency performance and helps optimize ESS operating points to conserve active power reserves for contingencies. Therefore, the inertia of each region is maintained to help improve system frequency security.