Contribution Of Energy Storage System To Enhance Power System Voltage and Frequency Stability In Presence Of Distributed Generation Units

In power systems, the main control mechanism responsible for maintaining the grid frequency and voltage at their nominal values ​​and the exchange of real power between balancing zones at the programmed values ​​is called automatic generation control (AGC). The load frequency control loop named LFC controls the real power and frequency, while the automatic voltage control loop called AVR controls the reactive power and voltage. Variations in power demand disrupt the balance between active and reactive power, thus causing frequency and voltage deviations from the nominal values. Therefore, it is essential to design a robust and optimal regulator that is both accurate and responsive to maintain the system parameters within their nominal ranges. However, with the integration of clean energy and intermittent generation quality caused by climate change, generating fluctuations in system frequency, coordinated AGC-PMS control with hybrid storage systems is required to improve the quality and stability of power systems. A hybrid energy storage system (HESS) can improve frequency and voltage control by balancing supply and demand, stabilizing the grid, and ensuring backup power. This article proposes a study approach integrating both AGC and a power management system (PMS) within an isolated Microgrid. Taking into account the integration of renewable energy sources (RESs), the proposed approach favors the use of an HESS to reduce fluctuations induced by the integration of RESs, which are themselves affected by climate variations. The system studied includes a photovoltaic generator and wind farm. A hybrid energy storage system was installed to ensure power management and control. It consists of redox flow batteries (RFBs), superconducting magnetic energy storage (SMES), electric vehicles (EVs), and fuel cells (FCs). The coordinated AGC-PMS strategy was tested across different case studies. The results obtained show good performance and demonstrate the validity and effectiveness of the proposed method.