Network reconfiguration has long been used by distribution system operators to achieve certain operation objectives such as reducing system losses or regulating bus voltages. In emerging distribution systems with a proliferation of distributed energy resources (DERs), co-optimizing network topology and DERs' dispatches could further enhance such operational benefits. This paper focuses on the optimal network reconfiguration problem of distribution systems via an unbalanced ac optimal power flow framework, which rigorously addresses operation characters of unbalanced network, DERs, and voltage regulators (VRs). Two VR models with continuous and discrete tap ratios are studied and compared. The proposed co-optimization problem is formulated as a mixed-integer chordal relaxation-based semidefinite programming model with binary variables indicating line-switching statuses and tap positions. Several acceleration strategies by studying the structure of distribution networks are explored for reducing the number of binary variables and enhancing the computational performance. Case studies on modified IEEE 34-bus and 392-bus systems illustrate the effectiveness of the proposed approach.

Microgrid is regarded as the future power system configuration, which can be operated by connecting to the bulk power grid, as well as in stand-alone mode for serving microgrid loads during failures of upstream grid. This paper proposes a business model for operating the community-based multi-party microgrid, which involves critical loads and generators of multiple owners. Different from most operational microgrids with single owner of critical loads and on-site generators, the community-based multi-party microgrid discussed in this paper presents different structure and thus unique operating goals. An iterative bi-level model is proposed to simulate the interaction between the community microgrid operator (named as mini-ISO) and multiple parties for deriving good enough market clearing results during the microgrid’s normal operation status. On the other hand, a centralized energy management model is proposed to simulate the microgrid operation during major disruption events with limited generation resources and competing needs from multiple owners’ critical loads. Numerical simulations evaluate the effectiveness of the proposed operation framework for the community-based multi-party microgrid.

This paper studies the optimal operation of internet data centers (IDCs) in microgrid environments. The proposed model is to minimize the IDC microgrid operation cost, which consists of the operation cost of onsite generations, cost of purchasing power from the main grid, cost due to the repeated charging and discharging of onsite energy storage system (ESS), and the cost due to IDC workload shedding. Both preventive and corrective operation solutions, including power purchase from the main grid, onsite generation dispatch, as well as ESS and IDC workload scheduling are provided for provisioning IDC workloads while considering credible islanding scenarios of the IDC microgrid. Demand response capability of the IDC microgrid is achieved through the proposed optimal solution. The use of ESS for facilitating electricity load shifting is further analyzed via a sensitivity study for minimizing the operation cost of IDC microgrid. Numerical simulations demonstrate the effectiveness of the proposed optimal operation model for IDC microgrid.

Cascading failures pose a significant security threat to networked systems, with recent global incidents underscoring their destructive potential. The security threat of cascading failures has always existed, but the evolution of cyber–physical systems (CPSs) has introduced novel dimensions to cascading failures, intensifying their threats owing to the intricate fusion of cyber and physical domains. Addressing these threats requires a nuanced understanding achieved through failure modeling and vulnerability analysis. By analyzing the historical failures in different CPSs, the cascading failure in CPSs is comprehensively defined as a complicated propagation process in coupled cyber and physical systems, initialized by natural accidents or human interference, which exhibits a progressive evolution within the networked structure and ultimately results in unexpected large-scale systemic failures. Subsequently, this study advances the development of instructions for modeling cascading failures and conducting vulnerability analyses within CPSs. The examination also delves into the core challenges inherent in these methodologies. Moreover, a comprehensive survey and classification of extant research methodologies and solutions are undertaken, accompanied by a concise evaluation of their advancements and limitations. To validate the performance of these methodologies, numerical experiments are conducted to ascertain their distinct features. In conclusion, this article advocates for future research initiatives, particularly emphasizing the exploration of uncertainty analysis, defense strategies, and verification platforms. By addressing these areas, the resilience of CPSs against cascading failures can be significantly enhanced.

In recent years, global efforts towards a future with sustainable energy have intensified the development of renewable energy sources (RESs) such as offshore wind, solar photovoltaics (PVs), hydro, and geothermal. Concurrently, green hydrogen, produced via water electrolysis using these RESs, has been recognized as a promising solution to decarbonizing traditionally hard-to-abate sectors. Furthermore, hydrogen storage provides a long-duration energy storage approach to managing the intermittency of RESs, which ensures a reliable and stable electricity supply and supports electric grid operations with ancillary services like frequency and voltage regulation. Despite significant progress, the hydrogen economy remains nascent, with ongoing developments and persistent uncertainties in economic, technological, and regulatory aspects. This paper provides a comprehensive review of the green hydrogen value chain, encompassing production, transportation logistics, storage methodologies, and end-use applications, while identifying key research gaps. Particular emphasis is placed on the integration of green hydrogen into both grid-connected and islanded systems, with a focus on operational strategies to enhance grid resilience and efficiency over both the long and short terms. Moreover, this paper draws on global case studies from pioneering green hydrogen projects to inform strategies that can accelerate the adoption and large-scale deployment of green hydrogen technologies across diverse sectors and geographies.