###### Abstract
Mission priority loads are given second priority and would include loads that are important to society but not essential to the functioning of smart critical  
Figure 1: Sample microgrid architecture. infrastructures (e.g., drug store, gas station, etc.). Lastly, non-critical loads would include residential and non-essential businesses (e.g., movie theaters). Generally, microgrids have fixed geographical limits and are planned in island mode to produce power sufficient to sustain mission-critical loads inside the geographic boundaries. Thus, based on the power accessible in island mode, the microgrid controller may implement load shedding, dropping non-critical loads and a portion of the mission priority loads [5]. Furthermore, microgrids are required to possess the capability to shift efficiently from island mode to grid-connected operation, providing re-synchronization with minimal consequence to significant loads through the transition phases. Unlike the nanogrids used in residential settings, a significant obstacle to the implementation of industrial size microgrids is the high cost in constructing, operating, and maintaining a microgrid. Currently, industrial capacity microgrids are mostly owned by an individual private organization. Recognizing the non-linear economic costs of implementing microgrids [8], the authors in [9] advocated for shared mid-size microgrids, with the expense borne by both the vital infrastructure propriators with critical loads (e.g., cellular network operators and hospitals) and the government organizations that will utilize the infrastructures during disaster recovery. This shared community use approach could be facilitated by government-sponsored financing and tax credits. Furthermore, it may justify either re-insurance or bonding mechanisms to help in reducing the cost. Here, the goal of this work is to design and place microgrids based on minimizing the overall expenses and to ensure power flow connected over the most vital critical infrastructure parts. Therefore, the proposed design is able to achieve significant techno-economical merits for microgrids. Related work on microgrids includes using microgrids to improve radial distribution power grid restoration after a natural disaster [5; 10] and dynamically forming local microgrids around distributed generation sources after a disaster [11]. [PERSON] [6] introduced the notion of employing a microgrid for the purpose of enhancing both power resilience and for alleviating climate change impacts. Nevertheless, this early work did not propose a method for determining the location of microgrids to improve the resilience of different critical infrastructures viewed as a group. In [12], the authors suggested using an algorithm to achieve multi-agent resource allocation in distributed scenarios through a shared microgrid, including residential and commercial buildings, with the least amount of information exchange between the users. However, their study lacks the commercial and residential segments by not assigning the priorities to critical nodes in the network. The bulk of the research literature on critical infrastructures within smart-city schemes has focused on optimizing performance and providing new functionalities. Previous work covering smart-city resilience has focused specifically on developing frameworks [13] or \"solidifying\" critical infrastructures. Traditionally, policy-makers mandated or supported hardening techniques such as constructing flood barriers and rebuilding levees according to the probability of 1 in 100-year situations. However, when considering smart critical infrastructures and the increasing weather variability, planners need to move beyond physical hardening techniques, adopting new preparedness methods and policies that acknowledge the dependence on both power and ICT. In [9], a structure for providing power and ICT is developed to enhance smart city critical infrastructure services in post-disaster conditions.