Energy management systems for microgrids

This work presents a pilot hybrid (AC and DC) microgrid, comprised of a gas microturbine emulator, a small wind turbine emulator, photovoltaic panels, an energy storage system, controllable AC and DC loads and static converters. This is a project sponsored by Tractebel Energy Brazil, aimed at studying microgrids in order to evaluate its use in creating value for customers. This allows them to use their energy in the most efficient way, taking advantage of intelligent distributed energy resources. The focus of this paper is mainly on the microgrid energy management system, which plays the role of the economic dispatcher. The cost of operation is minimized by taking into consideration grid energy costs, fuel costs, O&M and equipment wear as well as diverse operation restrictions of the system, such as grid exchange limits, power limits of the sources, battery dynamics, among others. The resulting optimum power set points for the sources are calculated based on demand and renewable generation forecasts, in order to guarantee the most economic operation. A simulation platform was developed to evaluate the behaviour and costs of similar microgrids, in which the specification of the sources can be arbitrarily defined. The static operation can be viewed and the resulting electrical transient dynamics can be analysed for user-defined moments within the simulated results. Study scenarios will be presented using this tool, showing the effectiveness of a microgrid management system in real-life representative situations.