Implementation of BESS Load Frequency Control in Islanded Microgrid System by Considering SOC

Abstract

In islanded microgrid, fluctuating operations and intermittency of renewable energy sources (RES) are the challenges of its operation. When droop control is applied on fossil-fueled generator, those challenges can be overcome. However, droop control makes the system working outside the permissible frequency range. Installing battery energy storage system (BESS) could be an option of frequency problem which its ability to regulate the frequency. In BESS operation, battery state-of-charge (SOC) is an important issue since it reflects BESS availability. Hence, a proper of BESS control is needed that it can participate actively to the system called Load Frequency Control (LFC). Furthermore, SOC control in BESS should be included to ensure BESS availability. In this paper, a BESS control that able to regulate system frequency and keep its SOC in certain range is introduced. In order to actualize these functions, shifted-LFC is used. This control will be simulated on diesel-fueled generator-photovoltaic (PV)-BESS microgrid system to observe the impact of installing the proposed control. Under this control, BESS can participate in regulating microgrid frequency and maintaining SOC level within a certain range.