Day-Ahead Energy Management for Isolated Microgrids Considering Reactive Power Capabilities of Distributed Energy Resources and Reactive Power Costs

In this paper, a day-ahead energy management (EM) for isolated microgrids (MGs) is proposed to obtain the optimal dispatch such that the costs related to the fuel consumption of diesel generators, load shedding, and renewable energy curtailment are minimized. Usually, fuel consumption costs of diesel generators are considered to be dependent on active power generation only. However, neglecting the related reactive power costs might result in increased operation costs and deviations in the dispatches from the optimal solutions. Hence, this paper co-optimizes the costs related to both active and reactive powers of diesel generators. In addition, this study considers the reactive power capability of inverter-interfaced distributed energy resources (DERs). The energy management problem is formulated as a nonlinear programming problem in GAMS environment and is solved using the CONOPT solver. Four different cases are presented to show the effect of considering the reactive power costs of the diesel generators and the reactive power capability from the inverter-interfaced DERs on the operating costs and dispatch results of the isolated MG.