Optimal power scheduling of renewable energy systems in microgrids using distributed energy storage system

The rapid depletion of fossil fuel resources and increase in demand of electricity has renewed interest in micro-grids (MGs). Incorporating renewable energy sources (RESs) and storage devices into MG could play a vital role in enhancing the reliability of the system. However, due to the intermittent nature of RESs, voltage fluctuations may occur in the system. Therefore, storage devices can be the most viable option to handle the intermittent issues of RESs. Nowadays, handling a group of batteries with different ratings in the MG has been a major focus of research. The batteries with different ratings used for storage as well as grid support is termed as a distributed energy storage system. This work mainly emphasises on optimal power management of an MG by controlling the charging and discharging rates of individual battery. A droop-based controller is proposed for optimal power management of batteries. An aggregator has been suggested at the MG which distributes the power among the various charging stations (CSs) and each CS finally distributes the power among the individual batteries based on droop participation factor. Moreover, the charging and discharging rates of batteries are controlled to achieve the desired power flow between the MG and CSs. The simulation results show the efficacy of the controller to meet the desired power at the MG. The proposed system is compared with an existing system to prove the efficacy of the proposed controller. Moreover, all the critical cases have been considered, such as the sudden failure of any generating unit. It has been observed that due to sudden failure of any generating unit, CSs manages power of the MG by altering charging and discharging rate of the batteries.