Emergency power control of virtual energy storage systems for improved grid stability

• Development of a frequency stability margin based VESS control strategy. • Systematic tuning of control parameters using sensitivity analysis and SFR model. • Validation of adaptive VESS response across varying power imbalance scenarios. The ongoing transformation of electrical power systems, driven by the integration of renewable energy sources and the adoption of hybrid alternating current and direct current grid architectures, presents new challenges for maintaining system stability. The shift from traditional synchronous generators to converter-based technologies reduces system inertia, increasing the risk of rapid frequency and voltage instability, particularly during emergency events. Existing fast frequency response services, typically provided by battery storage systems or specialised equipment, are often limited by proprietary designs, lack of interoperability, and insufficient scalability. This paper proposes a generalised emergency power balancing method based on controllable virtual energy storage systems. These systems aggregate various distributed energy resources, such as electric vehicles, flexible electrical loads, and small-scale storage units. When coordinated by system operators, these resources can provide fast, bidirectional power regulation, reducing reliance on consumer disconnections. Building on the concept of frequency stability margin, the paper introduces a decentralised control algorithm that enables rapid and adaptive power regulation. The algorithm is designed to respond strongly in severe grid disturbances while moderating its actions during less critical events. In addition to frequency support, the control strategy can be extended to manage voltage stability, providing a dual-purpose solution for improving system resilience. Simulation results show that the proposed control strategy effectively mitigates both frequency and rate-of-change deviations, achieving a stable and coordinated system response under a wide range of operating conditions. The results confirm that the proposed approach enhances system stability, offering a scalable and flexible solution for future emergency power balancing needs.