Practical Energy Management Systems for Isolated Microgrids

This paper presents practical energy management system (EMS) models which consider the operational constraints of distributed energy resources, active-reactive power balance, unbalanced system configuration and loading, and voltage dependent loads. A novel linearization approach is proposed and validated based on the fact that, for isolated microgrids, due to the characteristics of feeders, network losses, and voltage drops across feeders are relatively small. The proposed EMS models are mixed integer quadratic programming problems, requiring less computation time and thus suitable for online applications. The practical EMS models are compared with a typical decoupled unit commitment and optimal power flow-based EMS with and without consideration of system unbalancing. The models, along with “standard” EMS models, are tested, validated, and compared using a CIGRE medium voltage benchmark system and the real isolated microgrid of Kasabonika Lake First Nation in Northern Ontario, Canada. The presented results demonstrate the effectiveness and practicability of the proposed models.