A Comprehensive Review of the State-of-the-Art of Secondary Control Strategies for Microgrids

Abstract

The proliferation of distributed energy resources in distribution systems has given rise to a new concept known as Microgrids (MGs). The effective control of MGs is a crucial aspect that needs to be prioritized before undertaking any implementation procedure. This article provides a comprehensive overview of hierarchical control methods that ensure efficient and robust control for MGs. Specifically, it focuses on the secondary controller approaches (centralized, distributed, and decentralized control) and examines their primary strengths and weaknesses. The techniques are thoroughly discussed, deliberated, and compared to facilitate a better understanding. According to functionality, the hierarchical-based control scheme is allocated into three levels: primary, secondary, and tertiary. For secondary control level, the MG communication structures permit the usage of various control methods that provided the significance of the secondary controller for consistent and reliable MG performance and the deficiency of an inclusive recommendation for scholars. Also, it gives a review of the literature on present important matters related to MG secondary control approaches in relation to the challenges of communication systems. The problem of the secondary level control is deliberated with an emphasis on challenges like delays. Further, at the secondary layer, the distributed control techniques for reducing communication system utilization and then reducing communication system delays are conferred. Furthermore, the benefits and limitations of various control structures, such as centralized, decentralized, and distributed are also discusses in this study. Later a comparative analysis of entire control approaches, the best methods of control according to the author's perspective are also discussed.

Recent developments of demand‐side management towards flexible DER‐rich power systems: A systematic review

“…Here, the control methods and levels are discussed to deal with the state or data gained from various power system components and take necessary actions to achieve the DSM strategies [216][217][218]. In the power system operation, the control strategies are divided into four control levels based on planning aspects and ordered response actions: local, secondary, central/emergency, and global [218].…”

“…Here, the control methods and levels are discussed to deal with the state or data gained from various power system components and take necessary actions to achieve the DSM strategies [216][217][218]. In the power system operation, the control strategies are divided into four control levels based on planning aspects and ordered response actions: local, secondary, central/emergency, and global [218]. The local control level regulates the primary frequency or power quality issues of the generators to respond to any energy interruptions due to an unbalance between generation and demand and to restore normal operation after these disturbances.…”

Local DER Control with Reduced Loop Interactions in Active Distribution Networks

“…This mutual interaction leads to system operating conflicts and also to voltage instability [14][15][16]. The techniques employed to address this problem are categorized in two main approaches [17,18]. The first is based on centralized and/or distributed techniques which guarantee optimal solutions to the voltage control problem, for example, in term of power loss minimization [19][20][21][22].…”

Development of a Cost-driven, Real-Time Management Strategy for e-Mobility Hubs Including Islanded Operation

“…It is important to observe that communication delays must be considered in the control processes. Communication delay may be attributed to a range of factors including physical distance between equipment, processing capacity, communication bandwidth among other causes [26][27][28][29]. Although unlikely to happen, a large delay in communication (»5s) could cause safety issues.…”