Enhancing Frequency Emergency Control with Battery Energy Storage Systems in Low-Inertia Power Grid

The high penetration of renewable energy into the power grid results in a reduction of system inertia. Consequently, in the event of faults like DC blocking fault, low-inertia systems exhibit severe frequency fluctuations, thereby triggering the activation of stability control devices and resulting in substantial economic losses. Frequency emergency control is of great significance for ensuring the safe and stable operation after large disturbances. This paper combines energy storage control with frequency emergency control. Specifically, it integrates the actual output of the energy storage into the generation tripping tuning process, thereby reducing the amount of generation tripping, optimizing the frequency intervals and delays of generation tripping. This paper constructs an optimization model for the coordinated operation of energy storage systems, consisting of two stages: optimization tuning and simulation verification. The optimization tuning module includes a scenario selection process considering system inertia and a generator tripping tuning process, which combines the energy storage output to obtain an optimized generator tripping scheme. The verification module consists of an energy storage control model based on MPC-MHE (Model Predictive Control and Moving Horizon Estimation) and an energy storage virtual inertia control process, verifying the effectiveness of energy storage control under the proposed generator tripping scheme. Finally, a provincial-level power grid is taken as a case study to validate the effectiveness of the proposed energy storage control strategy.