Frequency Stability Assessment of Multiple Virtual Synchronous Generators for Interconnected Power System

Virtual inertia (VI) control is a promising concept to ensure the frequency stability of systems dominated by high renewable energy. Supply of VI is established by an inverter-based energy storage system, which can emulate a necessary behavior of synchronous generation in terms of inertia and damping properties, enhancing the entire system stability. This work investigates the dynamic behavior of multiple-VI in an interconnected system. A frequency control model of a three-area interconnected system with multiple-VI control is presented. Then, contrastive test scenarios are conducted to evaluate the necessity of the VI control in both islanded and grid-connected modes. The obtained results show that the genuine dynamic behavior of a grid-connected mode can lead to critical frequency issues with damping insufficiency. The instability in a grid-connected mode can be resolved by the development of multiple-VI control. The promising results will be useful and essential for further research on an interconnected system in respect to a detailed model-based frequency and inertia power response.