Optimal Coordination of Active Generators in a Grid-Connected Microgrid

Abstract

In a microgrid composed of distributed active generators based on renewable energy sources, with heterogeneous features and generation profiles, the availability of the energy resource, the energy reserve capacity, and the degradation of the storage unit, define the constraints for the management and dispatch of each active generator. This can result in sub-optimal use of distributed energy resources in comparison with the operation of a single generation unit. However, under the current trend oriented to distributed installations, the overall operation could be improved if an aggregated operation is considered within the management level. This paper proposes a coordinated operation of the storage units associated with distributed active generators for a hybrid grid-connected microgrid. In order to optimize the use of the active generators, including the equalization of the state of charge of the storage units, a mathematical model is proposed. This model tries to avoid uneven degradation of the storage units, and, consequently, enhance the reserve capacity and reduce the depth of discharge by achieving the operation of the distributed system as a unified system. The simulations are carried out in GAMS and MATLAB in order to validate the system’s operation. The results show a better performing grid-connected microgrid with the proposed approach.

Keywords

• distributed active generators
• energy storage equalization
• energy management systems
• microgrids