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This paper presents planning and optimization of standalone DC microgrids for rural and urban applications in India. Load profiles in the form of a rural village, an urban residential building and a business organisation are considered for the study. Using these load profiles, different microgrid configurations with generation from PV, wind turbine and biodiesel generators are constructed. Optimization studies are then carried out using Homer Energy software to determine the optimal system configuration which has the lowest cost of energy. Historical data of hourly solar irradiation and wind speed were also used in the study to obtain a realistic result. A special case study for the rural scenario with a partial connectivity to the grid is also conducted which is reminiscent to the poor reliability of supply in India. The study also gives a detail comparison between the various cost components, electrical productions, energy management and emissions for each of these systems. The results of optimization show reasonable cost of electricity for reliable supply of power for the various load configurations as compared to the actual grid prices. [ABSTRACT FROM AUTHOR]

Recent events have shown that cyber attacks are becoming real threats to the power system reliability and resiliency, and there is no exception to the DC microgrids which would become popular in the future. Currently, most secondary controls in DC microgrids heavily rely on communications, making them specifically vulnerable to cyber attacks. This paper presents a resilient distributed control based on the average consensus algorithm and the proportional-integral (PI) consensus algorithm to enhance the system resilience against denial of service attacks and improve the microgrid stability, particularly in the presence of constant power loads. The proposed control casts the average voltage restoration problem into an optimization problem, and because of this, the voltage control is immune to the communication damage caused by malicious denial of service attacks. Moreover, the small-signal stability model of the DC microgrid with distributed energy storages and constant power loads is established, and the impacts of varying constant power loads, controller parameters and communication topology on the system stability are analyzed. Simulations are conducted to verify the effectiveness of the proposed method. • Global voltage and current regulations are realized by distributed mechanisms. • Distributed controllers can keep the DC microgrids stable during cyber-attacks. • Proportional-integral consensus based controllers can recover from Denial of Service attacks. • Distributed controllers contribute to improving stability in the presence of constant power loads. [ABSTRACT FROM AUTHOR]

The proliferation of renewable energy resources to the next level optimizes microgrid utilization to manage the disturbances effectively. A direct current microgrid achieves solicitous attention worldwide due to the development of several DC loads, higher efficiency, and advancement in power electronic devices. The study substantially addresses the merits of DC microgrid over AC microgrid, recent research trends, fault localization, classification, and characterization to understand critical protection aspects. The paper has sought out the elusive protection challenges along with grounding impacts associated with DC microgrid in-depth. It articulates the relationship between the converter performance and peculiar load impact with grid security. Also, it presents a strategy for the safe deployment of renewable energy resources where protection margins are least affected. This article is explicitly reviewed and analyzed the pros and cons of the different protection strategies. The subsequent modifications and analysis of protective and fault current limiting devices are discussed to assist the protection scheme. The comprehensive protection strategy is tightly coupled with its components' security. Therefore this study critically examines the protection techniques for different elements forming the microgrid along with the jurisdiction. Finally, concluding remarks with a complete roadmap for future research are laid out. • It presents merits, research and publication trend in DC microgrid protection and portrays a few real-time microgrid models. • It illustrates elusive protection challenges and the effect of converter performance on grid security. • It states a strategy for the safe deployment of renewable energy resources. • It addresses the subsequent modifications in protection and current limiting devices to assist the protection scheme. • The study critically examines the protection techniques for different element forming the microgrid along with the jurisdiction. [ABSTRACT FROM AUTHOR]

Amalgamation of distributed energy resources (DER) with power system is developing as an emerging power framework. It is ecumenically based on the paramount issues such as extensive use of technologies based on distributed energy resources, shortage of fossil fuel in future, liberalism of electrical service industries and custom vigilance on environmental impact of the conventional method of generating electrical power. These issues are transmuting the concept of conventional power generation globally and introduce incipient challenges in the generation and distribution system. The interconnection of distributed generators has initiated the concept of microgrid which is the assemblage of interconnected distributed generators, intermediate storage units and loads. The pragmatic application of microgrid faces numerous technical challenges. Scheming with a congruous protection scheme is one of the solemn challenges in a microgrid framework. The level of fault current in both the modes of operation, active distributed generation, two-way flow of power, increased value of impedance and quality of communication network are the profuse challenges in scheming an efficacious protection technique. The protection scheme must be reliable, selective, fast and susceptible in both the working modes. This paper presents the meticulous study of the architecture of AC microgrid, DC microgrid and hybrid microgrid along with the associated protection issues and solutions. It also provides the censorious assessment of available challenges in the protection of microgrid in both grid-tied & islanded mode and available protection strategies for both AC microgrid and DC microgrid. An all-inclusive review has been done in each section considering the latest developments along with the future progression in the field of microgrid protection. • Discuss the various frameworks of microgrid. • Detailed emphasis on the protection issues of AC microgrid and DC microgrid. • Identify the various protection challenges in grid-tied mode and islanded mode. • Critical analysis and comparison of available protection techniques. • An all-inclusive review of the latest developments in the field of protection. [ABSTRACT FROM AUTHOR]