Frequency Improvement in Microgrids Through Battery Management System Control Supported by a Remedial Action Scheme

Abstract

In this work, we propose a battery management system control (BMSC) for primary frequency regulation. In many operational scenarios, the microgrid (MG) results in a weak frequency due to the low inertia of the renewable energy sources and the highly dynamic loads. The proposed BMSC improves the operation and control of the MG by managing the energy stored in the battery storage systems (BESS) through the battery management system (BMS); continuous frequency control of the MG is achieved, preserving the energy availability of BESS. The proposed system performs frequency control actions in real time in the MG operation through BMSC, and it is not required to know the insolation and wind speed forecasts, due to the high uncertainty in the forecasts. Frequency regulation is achieved by evaluating the energy required by the MG, and by controlling the charging and discharging operations that ensure that the BESS resource is available. Due to the highly dynamic MGs, the contribution of the battery in each period is limited to a percentage of its capacity, avoiding deep discharges and the loss of premature energy provided by the battery. The control will apply a remedial action scheme to keep the frequency within the operating margins if the BMS cannot regulate the frequency. The system proposed here is evaluated using an MG system in an island operation. The results show the feasibility of the proposed system under different operating conditions and the compliance with the technical operational specifications of the BESS.