State of the Art of Low and Medium Voltage Direct Current (DC) Microgrids (original) (raw)
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An Overview of DC Microgrids and Distribution Systems
GRD Journals, 2018
This paper presents an impression of the latest advancements in DC Distribution Systems. For the substantial increase in attention been gaining recently over the DC power systems, the researchers started exploring many issues that need to be taken account during this evolution period from existing conventional power systems to advancements in smart grids involving DC Microgrids. The researchers exertions recently were focused mostly toward the viability of implementing DC Distribution Systems on a given application, design related aspects on DC Distribution Systems such as its architecture, voltage level or the distinctive challenges connected with protection and stability of DC Power Systems. These research efforts were characterized, discussed and studied in this paper to assess where we presently existing on the changes in electrical energy systems from a staggering fully AC power system to the more flexible hybrid AC-DC power system. Additionally, the obstructions against more implementations of the DC distribution systems and few of the proposed remedies to overcome these obstacles will be discussed in this paper. One of the main difficulties to increase DC system utilization in insertion is due to the lack of proper standards in the system. The most recent issues, standardization efforts will be discussed, summarized and presented.
DC microgrids and distribution systems: An overview
This paper presents an overview of the most recent advances in DC distribution systems. Due to the significantly increasing interest that DC power systems have been gaining lately, researchers investigated several issues that need to be considered during this transition interval from current conventional power systems into modern smart grids involving DC microgrids. The efforts of these researchers were mostly directed toward studying the feasibility of implementing DC distribution on a given application, DC distribution design-related aspects such as the system architecture or its voltage level, or the unique challenges associated with DC power systems protection and stability. In this paper, these research efforts were categorized, discussed and analyzed to evaluate where we currently stand on the migration path from the overwhelming fully AC power system to a more flexible hybrid AC/DC power system. Moreover, the impediments against more deployment of DC distribution systems and some of the proposed solutions to overcome those impediments in the literature will be discussed. One of the obstacles to increased DC system penetration is the lack of standards. This problem will be discussed, and the most recent standardization efforts will also be summarized and presented.
Transition towards DC micro grids: From an AC to a hybrid AC and DC energy infrastructure
2017
Our electricity is predominantly powered by alternating current (AC), ever since the War of Currents ended in the favor of Nicola Tesla at the end of the 19th century. However, lots of the appliances we use, such as electronics and lights with light-emitting diode (LED) technology, work internally on direct current (DC) and it is projected that the number of these appliances will increase in the near future. Another contributor to the increase in DC consumption is the ongoing electrification of mobility (Electric Vehicles (EVs)). At the same time, photovoltaics (PV) generate DC voltages, while the most common storage technologies also use DC. In order to integrate all these appliances and technologies to the existing AC grid, there is a need for converters which introduce power losses. By distributing DC power to DC devices instead of converting it to AC first, it is possible to avoid substantial energy losses that occur every time electricity is converted. This situation initiated ...
Applied Sciences, 2020
This editorial manuscript reviews the papers accepted for publication in the Special Issue “DC & Hybrid Microgrids” of Applied Sciences. This Special Issue, co-organized by the University of Pisa, Italy and Østfold University College in Norway, has collected nine papers from 25 submitted, with authors from Asia, North America and Europe. The published articles provide an overview of the most recent research advances in direct current (DC) and hybrid microgrids, exploiting the opportunities offered by the use of renewable energy sources, battery energy storage systems, power converters, innovative control and energy management strategies.
Development of a photovoltaic low voltage DC microgrid for buildings with energy storage systems
2017
In order to develop a sustainable datacenter, which would help to validate energy management and task scheduling algorithms, a low voltage direct current (LVDC) microgrid (MG) has been deployed in the ADREAM Building-Integrated Photovoltaic (BIPV) of the LAAS-CNRS in Toulouse, France. This MG is composed of a 1 kWp PV source, 300 Ah – 36 V lead-acid batteries, 330 F – 48 V supercapacitor (SC) pack and DC loads (cloud servers, USB chargers, sensors monitoring an apartment…). A very simple and efficient energy flow management strategy, based on the " DC bus signaling " approach has been implemented. It takes advantage of the DC bus architecture and enables a scalable electrical structure constituted of several sources, loads and storage elements easy to connect/disconnect via their converters. The development of this MG put in evidence the need for future theoretical developments regarding the determination of optimal DC bus signaling thresholds.