Real-time supervisory control strategy for a grid-connected microgrid using hardware-in-the-loop simulation

Abstract

Incorporating renewable energy sources and battery energy storage systems (ESS) into electrical distribution networks brought new approaches to energy management systems. This paper proposes a novel energy management system (EMS) scheme for a grid-connected residential microgrid. The designed EMS is composed of two interconnected layers. The upper layer contains a supervisory controller, based on a priority-based approach, to reduce microgrid operation costs while accounting for dynamic changes in household preferences and electricity price fluctuations. The lower layer employs Mixed Integer Linear Programming (MILP) optimization to solve the economic dispatch problem, considering the RES curtailment, the ESS management, the demand response mechanism, and the connection with the main grid. The developed EMS is tested and validated through a hardware-in-the-loop simulation using the OPAL-RT simulator. Applied on four different typical days over the year, the results demonstrate that the developed strategy can meet the varying energy needs of the microgrid, establishing an efficient power-sharing control between the loads, the energy storage system and the main grid. Further, the EMS exhibits an operational cost reduction ranging from 58 % in summer to 50 % in winter. Moreover, the MILP optimization is compared to particle swarm optimization (PSO) and linear programming (LP) to confirm the consistency of the proposed EMS.