Day-ahead operational scheduling of a microgrid connected to the distribution network

Abstract

This work contributes to microgrid (MG) management by proposing a day-ahead scheduling model that optimizes the operation of distributed resources and energy exchange with the distribution network. The MG comprises renewable energy sources (solar photovoltaic and wind), controllable loads (an intelligent lighting system, electric vehicles, water and irrigation pumps), and an Energy Storage System (ESS). The proposed methodology formulates an optimization problem to minimize the MG´s operating cost. This problem is solved to define the day-ahead operating modes, determining the status of each MG load, the grid connection mode, and the ESS operating strategy. The objective cost function incorporates the costs of photovoltaic and wind generation, the cost associated with energy supplied by the ESS, and the cost of energy consumed from the distribution grid. The ESS cost is modeled in detail by considering both operating (cycle) and aging (calendar) costs. Simulation results demonstrate that including both cost components extend the ESS lifespan by avoiding economically unjustified deep discharges. Additionally, the integration of the ESS enhances the operation of distributed generation sources. The implementation of the energy management strategy results in a 59% annual cost reduction (USD 1,762.08) and increases the ESS lifetime from 1.32 to 2.50 years.