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• A cooperative control for the online energy management of a microgrid. • The methodology adopts the Lyapunov theorem encompassing the sensitivity theory. • It aims to ensure real-time power balance within the MG at minimal operating cost. • Simulations demonstrated the self-adaptability of the proposed controller. This paper develops a cooperative control methodology for the online energy management of grid-connected microgrids. The main aim of this methodology is to actively manage the active power outputs of all dispatchable energy sources available within the microgrid as well as the power exchanged with the utility grid so as to match the total load demand at the minimum operating cost. This implies to solve a constrained multi-objective dynamic optimization problem aimed at minimizing the total microgrid operating costs and ensuring the real-time balance within the microgrid in compliance with its technical-operational constraints. Lyapunov's theorem using sensitivity theory is adopted to solve this optimization. To test the performances of the proposed control methodology, several computer simulations corresponding to different operating scenarios have been conducted on the PrInCE Lab experimental microgrid built at the Polytechnic University of Bari. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • Proposes a second-order dynamic model to represent an actual So–Nick BESS. • An input–output identification procedure is proposed for parameters identification. • The procedure is based on the Sensitivity theory involving the Lyapunov function. • Experimental tests prove the practical applicability of the proposed methodology. Abstract The aim of this paper is to derive an accurate input/output dynamic equivalent model of a So–Nick Battery Energy Storage System (BESS). For this purpose, an on-line identification methodology has been applied. By this methodology, unknown model parameters are identified in the continuous time domain by solving an optimization problem aimed at minimizing the error between output trajectories of the physical system and its dynamic equivalent model. The methodology is based on the Sensitivity theory involving the Lyapunov function, ensuring the stability of the algorithm. Experimental results are used to validate the proposed approach by adopting the Sodium–Nickel Battery Energy Storage System (BESS) embedded into the experimental Prince Lab of the Polytechnic University of Bari, Italy. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to examine how a coordinated control strategy for managing the active power reserve in isolated microgrids is presented. This methodology can be applied in those microgrids where a specified generator assumes the role of the isochronous generator for the overall system. The derived algorithm evaluates control actions in the on-line environment by solving a constrained dynamic optimization problem aimed at maximizing the overall spinning reserve and, in particular, the reserve offered by the master unit equipped with the isochronous governor controller. The solution of this problem is obtained by adopting the direct Lyapunov theorem applied to the Sensitivity theory, ensuring the algorithm’s stability. Tests performed on the experimental microgrid, which has been built at the Polytechnic University of Bari, demonstrated the ability of the proposed methodology to share the regulation burden among all sources and storage systems, establishing adequate reserve margins of the master unit. [ABSTRACT FROM AUTHOR]

The aim of this paper is to define an organized approach for improving the economic, reliable and secure operation of microgrids operating either in the On-grid or in the Off-grid. According to this methodological approach, a microgrid can be operated into five Operating Modes and five Transitions. Proper management of each of them has been examined and implemented on the existing microgrid developed at the Prince — Electrical Energy System Lab of the Polytechnic of Bari. This microgrid can be considered a hard test bed for dynamic stability studies since it is an inertialess system. [ABSTRACT FROM AUTHOR]

• Identify the main design features of different microgrids around the world. • This paper explores the main issues arising from the development of a microgrid. • An attempt to define potential solutions to overcome the main technical issues. • It defines guidelines for practical implementation and operation of microgrids. A microgrid is a small portion of a power distribution system with distributed generators along with energy storage devices and controllable loads which can give rise to a self-sufficient energy system. From the utility grid side, a microgrid is seen as an equivalent generator that is able to seamlessly disconnect and operate autonomously once a fault affects the main grid. The design, installation and operation of such systems lead to dealing with a number of technical and operational challenges including control, protection and infrastructure requirements. To help designers and researchers address these challenges and draw potential recommendations for practical microgrid implementations, in this paper a review of the main design features of existing microgrids is undertaken, also in light of the experience gained during the realization of the Prince Lab microgrid at Polytechnic University of Bari, Italy. The main control functions required to guarantee an economic, reliable and secure operation of a microgrid are also reviewed. Finally, key practical guidelines for monitoring, operation and implementation of microgrids are provided. [ABSTRACT FROM AUTHOR]