Smart hybrid energy management system for AC microgrid integrated to utility distribution grid

Abstract

This paper proposes a smart hybrid energy management system (EMS) with optimized coordination for an AC microgrid integrated to the utility distribution grid. The proposed EMS incorporates a hybrid scheme of rule based prioritization combined with an optimization module for the energy management of the AC microgrid under grid-connected and islanded conditions. This helps in minimizing the grid cost of operation through a systematic cost-benefit analysis of the microgrid. Besides, it aims at the reduction of carbon emissions by prioritizing renewable sources of energy. The proposed EMS offers precedence to the active power management of a photovoltaic (PV) source, a battery energy storage system (BESS) and a diesel generator under different operating conditions besides performing reactive power compensation using the grid-tied converters of PV and BESS which are dynamically limited by the EMS depending on the maximum VA rating of the respective entities and the present active power injected. This scheme ensures overall voltage stability at the point of common coupling (PCC). The simulation result and analysis establishes the effectiveness of the proposed EMS scheme.