Control Hardware-in-the-Loop Simulation on Fast Frequency Response of Battery Energy Storage System Equipped With Advanced Frequency Detection Algorithm

Fast frequency response (FFR) of battery energy storage system (BESS) is an effective way to mitigate the system frequency deviation induced by the fluctuation of power generation from the increased renewable energy resources and the impact of reduced system inertia caused by decreased synchronous generators. However, existing standards referring to technical requirements for the frequency measurement do not sufficiently consider abnormal grid conditions, such as voltage unbalance, frequency sweep, and dynamic voltage step. This article shows the impact of frequency measurement logic on the FFR performance of BESS in grid disturbance conditions by control hardware-in-the-loop (CHIL) testing and proposes improved frequency measurement logic based on a phase-locked loop (PLL). A benchmarking of the proposed PLL was conducted against existing PLL and discrete Fourier transformation-based frequency measurement logics. Finally, the FFR performance of BESS with each frequency measurement logic has been tested in CHIL simulation. This CHIL comprises the actual power plant controller, the actual bidirectional inverter control board, and a real-time simulator. In the CHIL experiments, several system disturbance situations likely to happen in existing power systems were considered as test cases and showed that the frequency measurement accuracy and latency were violated in some frequency measurement logics. Furthermore, this article reveals the effects of frequency measurement accuracy and latency on the FFR performance of BESS by a closed-loop power control simulation with a CHIL environment. In conclusion, considerations for the frequency measurement method used for FFR are proposed.