Power System Inertia in High-Renewable Penetration Power Systems and the Emerging Role of Battery Energy Storage

Very high levels of renewable generation uptake in Australia particularly in South Australia has demonstrated the need for new system operation and planning approaches to maintaining supply reliability and security, specifically in managing system frequency under both steady-state as well as dynamic recovery from disturbance/contingency events. This paper discusses power system frequency control and the crucial role that inertia plays in dynamic frequency control and enabling power systems and connected plant to ride-through/recover from frequency disturbances. The fundamental power swing equation which governs frequency behavior is first discussed. Latest frequency control mitigation options from Battery Energy Storage Systems (BESS) are then presented, followed by experimental fast frequency control testing and model validation work on a microgrid characterization testbed. Finally, examples of utility-scale BESS responses to recent transmission system frequency disturbances are discussed.