Communications uncertainties in isolated multi-microgrid control systems (original) (raw)

Design and Implementation of a True Decentralized Autonomous Control Architecture for Microgrids

2017

Microgrids can serve as an integral part of the future power distribution systems. Most microgrids are currently managed by centralized controllers. There are two major concerns associated with the centralized controllers. One is that the single controller can become performance and reliability bottleneck for the entire system and its failure can bring the entire system down. The second concern is the communication delays that can degrade the system performance. As a solution, a true decentralized control architecture for microgrids is developed and presented. Distributing the control functions to local agents decreases the possibility of network congestion, and leads to the mitigation of long distance transmission of critical commands. Decentralization will also enhance the reliability of the system since the single point of failure is eliminated. In the proposed architecture, primary and secondary microgrid controls layers are combined into one physical layer. Tertiary control is performed by the controller located at the grid point of connection. Each decentralized controller is responsible of multicasting its status and local measurements, creating a general awareness of the microgrid status among all decentralized controllers. The proof-of concept implementation provides a practical evidence of the successful mitigation of the drawback of control command transmission over the network. A Failure Management Unit comprises failure detection mechanisms and a recovery algorithm is iii proposed and applied to a microgrid case study. Coordination between controllers during the recovery period requires low-bandwidth communications, which has no significant overhead on the communication infrastructure. The proof-of-concept of the true decentralization of microgrid control architecture is implemented using Hardware-in-the-Loop platform. The test results show a robust detection and recovery outcome during a system failure. System test results show the robustness of the proposed architecture for microgrid energy management and control scenarios.

Advanced control and management functionalities for multi-microgrids

European Transactions on Electrical Power, 2011

This paper addresses the extension of the Microgrid concept, following a massive integration of these active cells in power distribution networks, by adopting a coordinated management strategy together with Distributed Generation units directly connected to the Medium Voltage distribution network. In order achieve this, a technical and commercial management scheme must be developed for coordinated control of a distribution system with Multi-Microgrids, which should take into account the specific technical capabilities and characteristics of each type of generating source. In particular, tools for coordinated voltage support and frequency control, as well as for state estimation have been developed for this type of networks. Concerning voltage support, a new methodology exploiting an optimization tool based on a meta-heuristic approach was developed. For state estimation, two approaches were considered: Multi-Microgrid State Estimation and Fuzzy State Estimation. Regarding frequency control, the hierarchical structure of the Multi-Microgrid is exploited to deal with the transition to islanded operation and load following in islanded operation. All these tools have proved to be efficient in managing the Multi-Microgrid system in normal interconnected mode and, in case of the frequency control, in islanded operation.

Communication Requirements in Microgrids: A Practical Survey

IEEE Access

Progress in Microgrid (MG) research has evolved the MG concept from classical, purely MG power networks to more advanced power and communications networks. The communications infrastructure helps control and manage the unreliable power outputs that most standard power generation elements of the MG (e.g., wind turbines and photo-voltaic panels) deliver. Although communication technologies do offer certain advantages for sensing and control, they generate other complications due to packet loss and packet latency, among other transmission impairments. In this work, we discuss the impact of communications on MG performance, establishing the requirements of data exchanges and system response in the three levels of a hierarchical control approach: primary, secondary, and tertiary. With a focus on the secondary level -responsible for ensuring the restoration of electrical parameters -we identify standards, networking protocols, and communication technologies relevant for the interoperability of MGs and clusters of MGs, including both modes of operation: isolated and grid-connected. We review theoretical approaches and practical implementations that consider the effects of the communications network on the general performance of the MG. Moreover, we undertake an experimental analysis of the influence of wired and wireless communication networks on MG performance, revealing the importance of designing future smart control solutions more robust to communication degradation, especially if wireless technologies are integrated to provide scalable deployments. Aspects such as resilience, security, and interoperability are also shown to require continuing efforts in research and practical applications.

A Secure Communication Architecture for Distributed Microgrid Control

IEEE Transactions on Smart Grid, 2015

Microgrids are a key component in the evolution of the power grid. Microgrids are required to operate in both grid connected and standalone island mode using local sources of power. A major challenge in implementing microgrids is the communications and control to support transition from grid connected mode and operation in island mode. Here, we propose a secure communication architecture to support microgrid operation and control. A security model, including network, data, and attack models, is defined and a security protocol to address the real-time communication needs of microgrids is proposed. The implementation of the proposed security scheme is discussed and its performance evaluated using theoretical and co-simulation analysis, which shows it to be superior to existing protocols.

Resilient and Cybersecure Distributed Control of Inverter-Based Islanded Microgrids

IEEE Transactions on Industrial Informatics, 2019

This paper addresses the security of distributed secondary control of inverter-based Distributed Energy Resources (DERs) in microgrids. The proposed cyber-secure scheme utilizes the Weighted Mean Subsequence Reduced (WMSR) algorithm at each DER to discard the corrupted information received from neighboring DERs. This algorithm requires the connectivity of underlying communication graph to be above a specific threshold. To cope with this requirement, a methodology is proposed such that each DER is able to virtually change the quality of communication links connected to that DER to enhance the connectivity of communication graph. Two islanded microgrid test systems are simulated to validate the effectiveness of proposed cyber-secure secondary control.

Distributed Control of Microgrids

Power Systems, 2019

The aim of this chapter discusses the relationship between hierarchical control and review of distributed control systems that is used in microgrids. The microgrids are differs from the conventional power systems. Because of the widespread use of advanced control technologies with features such as power electronics devices, detection/measurement applications, and communication infrastructures. These features of microgrids make it easier for renewable energy sources that are included in the power systems. Therefore, distributed control methods are applied in addition to centralized and decentralized controls for reliable operation of the system in microgrids and between different microgrids. This section discusses the features of these methods.

Scoping Study: Networked Microgrids

2014

This report presents a scoping study for networked microgrids which are defined as "Interoperable groups of multiple Advanced Microgrids that become an integral part of the electricity grid while providing enhanced resiliency through self-healing, aggregated ancillary services, and real-time communication." They result in optimal electrical system configurations and controls whether grid-connected or in islanded Scoping Study: Networked Microgrids

The Evolution of Research in Microgrids Control

IEEE Open Access Journal of Power and Energy, 2020

Microgrids (MGs), as novel paradigms of active Distribution Networks, have been gaining increasing interest by the and constitute an active area of research community in the last 20 years. Currently, they are considered as key components in power system decentralization, providing viable solutions for rural electrification, enhancing resilience and supporting local energy communities. Their main characteristic is the coordinated control of the interconnected distributed energy resources (DER), which can be realized by various methods, ranging from decentralized communication-free approaches to centralized ones, where decisions are taken at a central point. This paper provides an overview of this development focusing on the technical control solutions proposed for the various levels of their organization hierarchy. A critical assessment of selected, promising technologies is provided and open questions regarding the trend to more decentralized power systems are discussed.