A microgrid (MG) is a cyber-physical system with coupled power and communication networks. The centralized secondary control of MGs with periodical communications restricts system efficiency and resilience. This article proposes a distributed event-triggered secondary control scheme in islanded MGs with its cyber-physical implementation. The proposed control scheme operates with the reduced frequency of communications depending on the MG states change “events” (e.g., load variations and communication failures). Besides, the secondary control objectives, including frequency/voltage regulation and accurate real/reactive power sharing, are decoupled into two timescales. Instead of designing event-triggering conditions (ETCs) for each secondary control functions, only ETCs for power sharing control in slower timescale are designed. Thus, the communication burden is significantly reduced since communications among neighbor controllers are only needed at the event-triggered time. The proposed controller has been tested on a hardware-in-the-loop (HIL) platform, where the physical system is modeled in the OPAL-RT and the cyber system is realized in Raspberry Pis. The control effectiveness is validated by the HIL results.

The increasing integration of microgrids (MGs) in distribution networks forms the networked microgrids (NMGs). The peer-to-peer (P2P) control architecture is able to fully exploit the flexibility and resilience of NMGs. This paper proposes a multi-layer and multi-agent architecture to achieve P2P control of NMGs. The control framework is fully distributed and contains three control layers operated in the agent of each MG. For primary control, a droop control is adopted by each MG-agent for localized power sharing. For secondary control, a distributed consensus algorithm is proposed for frequency/voltage restoration and arbitrary power sharing among MGs. For tertiary control, the power loss in the NMG system is minimized by using alternating direction method of multipliers (ADMM). The architecture of the MG agent are designed, which processes the three control layers via information exchange among neighbouring agents. The proposed framework is validated in a hardware-in-the-loop test-bed, where NMG system with six buses and three MGs is emulated in the OPAL-RT, while the control algorithms are realized by a multi-agent system. The experimental results verify the effectiveness and advantages of the proposed framework, which demonstrates a practical control framework design for NMG systems.

Internet-of-Things concepts are evolving the power systems to the Energy Internet paradigm. Microgrids (MGs), as the basic elements in an Energy Internet, are expected to be controlled in a more flexible and corporate manner. This paper proposes a novel distributed control scheme for multi-agent systems (MASs) governed MGs in future Energy Internet. The control objectives are frequency/voltage restoration and proportional power sharing. The proposed control scheme considers both intra and inter MASs interaction, which offers group plug-and-play capability of distributed generators (DGs). The stability and communication delay issues in the control framework are also analysed. A multi-site implementation framework is presented to explain the agent structure as well as data exchange in local area networks and the cloud server. Then a cyber hardware-in-the-loop (C-HiL) experiment is conducted to validate the proposed control methods and multi-site implementation. The experimental results prove the effectiveness and application potentials of the proposed approach.

In this article, a distributed hierarchical control framework with coordinated secondary and tertiary levels is proposed for islanded microgrids (MGs). The structure and functionality of each agent are formulated to process simultaneously the secondary control and TC in a peer-to-peer communication network. First, the distributed secondary control is proposed for restoring system frequency/voltage while providing power sharing considering droop coefficients and upper level power dispatch orders. Then the distributed TC minimizes the network power loss in the islanded MG by using alternating direction method of multipliers (ADMM) algorithm. The multiagent system is designed to cover both control levels for cyber–physical implementations. A laboratory cyber–physical MG platform has been built to validate the proposed control framework in real-time and hardware-in-the-loop conditions. A six-bus three-DG MG is implemented on the platform and the experimental results validate the effectiveness of the proposed method.

Co-simulation is an emerging method for cyber-physical energy system (CPES) assessment and validation. Combining simulators of different domains into a joint experiment, co-simulation provides a holistic framework to consider the whole CPES at system level. In this paper, we present a systematic structuration of co-simulation based on a conceptual point of view. A co-simulation framework is then considered in its conceptual, semantic, syntactic, dynamic and technical layers. Coupling methods are investigated and classified according to these layers. This paper would serve as a solid theoretical base for specification of future applications of co-simulation and selection of coupling methods in CPES assessment and validation.