Evaluating the impact of BESSs in the Jeju island power system

This paper analyzes the mitigation of the unintended fluctuation of wind power generation output with BESSs (Battery Energy Storage System) in the isolated power system in Jeju island. Wind farms are modeled for the simulation that indicates the virtual system in 2014. In the simulation, BESSs are installed in each wind farm to smooth the fluctuation of wind farm output for stabilizing the grid frequency as soon as wind farms are tripped from the power grid. BESSs composed of Li-Ion battery cells and their capacities are calculated with considering SOC (State of Charge) and Life Cycle. To analyze the effectiveness of the BESSs to the Jeju power system, two kinds of simulations are carried out by using the PSCAD/EMTDC program. One is the steady state operation under the variable speed wind, and the other is the transient state operation when all wind farms in the east side and one wind farm in south side of Jeju island are disconnected suddenly from the Jeju power grid due to electric fault. These comparative studies will be useful to analyze the isolated power system stability.