Comparison of Field Test and Controller Hardware-in-the-Loop Simulation Results of Utility-Scale Battery Energy Storage System

The Battery Energy Storage System (BESS) is expected to mitigate the power supply-demand imbalance induced by the fluctuation of power generation from the variable renewable energy resources and the reduced system inertia caused by decreased number of synchronous generators. Since the BESS can quickly adjust its power output according to the grid frequency fluctuations, it is regarded as one of the most important resources providing the fast frequency response (FFR) service, which requests the resources to adjust their active power output according to the grid frequency fluctuations. From a point of view of the utility-scale BESS project development, estimating the dynamic performance criteria, such as response speed and control accuracy, in advance of the field commissioning is important. However, it is challenging since their power rating is more than MW scale. Based on the above awareness, controller hardware-in-the-loop simulation (CHILs) is regarded as the method enabling the verification of the expected dynamic performance of the utility-scale BESS at the initial stage of the project development. This paper compares the control response time and control accuracy of the BESS in three test environments consisting of CHILs , reduced-scale facility, and the actual utility-scale BESS built in GB. The results suggest that CHILs has a good compatibility with reduced-scale test and field test in terms of the dynamic performance of the BESS.