# Networked Microgrids: A Review on Configuration, Operation, and Control Strategies
## 1 Introduction  
The intensification of climate change poses a threat to power systems, leading to potential challenges like increased electricity demand and adverse impacts on power equipment. This convergence may result in critical issues, such as overloading and overheating, reminiscent of the 2003 blackout incident in the United States. The increasing annual intensity of climate change elevates the likelihood of severe weather events, contributing to a notable uptick in major power outages, as depicted in Figure 1[1]. Major power outages, exemplified by events in Texas and Quebec, can inflict substantial economic losses, as seen with the USD 130 billion impact in Texas [2], and USD 50 million impact in Quebec [3]. Additionally, such outages pose significant challenges for affected households, enduring prolonged periods without electricity. The extensive scholarly literature has been dedicated to enhancement of power networks' capability to withstand adverse weather conditions--a practice commonly referred to as enhancement of power system resilience. Researchers suggested diverse strategies for resilience enhancement, such as strategic planning techniques and system hardening methods [4]. A notably promising solution among the various proposed methods involves integrating controllable and smart technologies into the power system and strategically establishing networked microgrids (NMGs). NMGs encompass interconnected microgrids (MGs) capable of exchanging both power and information. This configuration is formed by partitioning distribution systems, linking multiple MGs to create a larger and more resilientpower system, as defined in IEEE standard 1547.4 [5]. This interconnected structure enhances resilience in managing energy resources and meeting electricity demand. Findings from [6] underscore the benefits of NMGs in reducing operating costs and improving power supply resilience compared to independent MGs. An illustrative example of the practical significance of this interconnected setup is observed in Adjuntas, Puerto Rico, where the resilience of two microgrids is notably elevated when integrated into a networked microgrid, as detailed in [7]. The versatility of NMGs positions them as a promising means to enhance overall system resilience. In this context, the present study aims at contributing to this growing research domain by delivering a systematic and contemporary review of the literature on networked microgrids. The main contribution of this article lies in its comprehensive review and categorization of studies within the domain of NMGs. Through meticulous examination, the article classifies the literature into two primary groups: networked microgrids' configuration and networked microgrids' control. In addressing the critical aspects of NMG configurations, the article delves into formation, power distribution, and operational considerations. Furthermore, it explores the control considerations of NMGs, encompassing their communication technologies and protocols, control architecture, modes, and schemes. Each of these components is systematically dissected into multiple subsections, elucidating specific features related to various technologies, methods, and concepts. The distinctive nature of this contribution lies in its detailed exploration of problem modeling, constraints, and objective functions within each subsection. This comparative analysis aids readers in discerning strengths and limitations in NMG configurations and control approaches. In the discussion section, a thorough analysis is conducted on all findings, gaps, and proposed solutions to formulate an optimal response to the challenges faced by NMGs. The discussion underscores the insufficient attention awarded to issues such as NMGs' frequency stability, reliability, recovery and reconfiguration time, expenses linked to remote switches and communication components, as well as the influence of real and transient events and the non-smooth characteristics of DGs and converters.