Impact of Advanced Load-Frequency Control on Optimal Size of Battery Energy Storage in Islanded Microgrid System

The application of battery energy storage (BES) in microgrid systems has attracted much attention in recent years. It is because the BES is able to store excess power and discharge its power when needed. In islanded microgrid systems, BES is starting to be considered as a unit that can regulate the system frequency. The control used in the BES to display frequency regulation performance is called load-frequency control (LFC). However, this participation resulted in the large size of the battery and high expansion planning cost. In this paper, an advanced LFC control that has frequency limitation compared to traditional LFC is proposed. The proposed control implies droop control as the base and has frequency limitations. Compared to the traditional LFC, the proposed control can reduce the system expansion planning costs. A performance simulation was done to validate battery performance. The results of the numerical simulation showed that the proposed control participated in reducing the operation cost. It directly led to a reduction in the expansion planning cost. A study of battery selection was conducted to draw the practicality of the BES sizing solutions.