Showing papers in "IEEE Electrification Magazine in 2016"
TL;DR: In this article, a series of advanced methods in control, management, and objective-oriented optimization that would establish the technical interface enabling future applications in multiple industrial areas, such as smart buildings, electric vehicles, aerospace/aircraft power systems, and maritime power systems.
Abstract: In recent years, evidence has suggested that the global energy system is on the verge of a drastic revolution. The evolutionary development in power electronic technologies, the emergence of high-performance energy storage devices, and the ever-increasing penetration of renewable energy sources (RESs) are commonly recognized as the major driving forces of the revolution. The explosion in consumer electronics is also powering this change. In this context, dc power distribution technologies have made a comeback and keep gaining a commendable increase in research interest and industrial applications. In addition, the concept of flexible and smart distribution has also been proposed, which tends to exploit distributed generation and pack together the distributed RESs and local electrical loads as an independent and self-sustainable entity, namely a microgrid. At present, research in the area of dc microgrids has investigated and developed a series of advanced methods in control, management, and objective-oriented optimization that would establish the technical interface enabling future applications in multiple industrial areas, such as smart buildings, electric vehicles, aerospace/aircraft power systems, and maritime power systems.
265 citations
TL;DR: According to a report from the White House Council of Economic Advisors, severe weather is the major cause of power grid outages in the United States, and it is estimated that weather-related power outages cost the American economy more than US$300 billion between 2003 and 2012 as discussed by the authors.
Abstract: power grids are supposed to be fault-tolerant, but you doubt the premise when you consider daily outages in more populated parts of the world and more recent brownouts and blackouts globally. Power engineers have been pushing forward the frontiers of power systems, and the hard-fought battle against the darkness is supposed to have been won, but the struggle is by no means over. Indeed, the electricity grid today is faced more intensely with challenging issues concerning cyber and physical system security. The recent blackout in Turkey on 31 March 2015, which knocked out the transportation infrastructure in major cities, causing massive traffic jams, is a testimony to this claim. It also shut down vital services to thousands of offices for several hours, inflicting business and social losses (see Figure 1). Although widespread blackouts are regarded as low-probability events, they carry immense socioeconomic costs. In such events, the burden of responsibility often lies with extreme weather events, cascading failures, or similar low-probability, high-impact incidents. According to a report from the White House Council of Economic Advisors, severe weather is the major cause of power grid outages in the United States. Meanwhile, it is estimated that weather-related power outages cost the American economy more than US$300 billion between 2003 and 2012. The report calls for increased investment to enhance the resilience of the power grid against rising incidences of extreme weather such as thunderstorms, hurricanes, and blizzards predicted by climate models.
160 citations
TL;DR: In this article, the authors proposed a solution for the installation of distributed sources in the lowvoltage (LV) grid, where most consumers are sparsely located, and they ease the integration of distributed generators with energy storage systems (ESSs) at a consumption level.
Abstract: Environmental concerns and new energy policies are causing energy systems to shift toward decentralization and sustainability. Electricity generation has been historically based on large-scale fossil and nuclear sources, even though in the last decade, the share of renewables has grown significantly. Microgrids (MGs) come as a suitable solution for the installation of distributed sources in the low-voltage (LV) grid, where most consumers are sparsely located. MGs ease the integration of distributed generators (DGs) with energy storage systems (ESSs) at a consumption level, especially renewable energy sources (RESs), such as solar panels and small wind turbines (WTs). By decentralizing electricity generation, it can now be produced in closer proximity to the consumer, thereby avoiding transmission and distribution losses and increasing the efficiency of the electricity grid, as well as higher power reliability.
144 citations
TL;DR: In this paper, the authors define microgrids as groups of energy resources, both renewable and/or conventional, and loads located and interconnected in a specific physical area that appear as a single entity to the alternating-current (ac) electric grid.
Abstract: Microgrids are defined as groups of energy resources, both renewable and/or conventional, and loads located and interconnected in a specific physical area that appear as a single entity to the alternating-current (ac) electric grid. The use of distributed resources to power local loads combined with the capability to operate independently of the ac grid makes microgrids a technically feasible option to address the concerns of sustainability, resilience, and energy efficiency. Furthermore, microgrids can operate while completely separated from the grid, representing a lower-cost option to provide electrical power to regions in developing countries where conventional ac grids are not available or are too unreliable. When connected to the ac grid, microgrids appear as controlled entities within the power system that, instead of being a burden to the ac grid power-management system, represent a resource capable of supporting the grid. Energy storage as the element responsible for balancing generation with load is critical to the success of the microgrid concept, and it is more important as larger penetration of renewable resources is present in the microgrid. Accelerated improvements in performance and cost of energy-storage technologies during the last five years are making microgrids an economically viable option for power systems in the very near future (see Figure 1).
133 citations
TL;DR: In this paper, a better understanding of residential electricity demand is key to addressing the envisioned transition of the electric power system from its traditional structure to one that is transactive, which is referred to as the transition from traditional buildings to transactive buildings.
Abstract: Approximately 100 million singlefamily homes in the United States account for 36% of the electricity load, and often they determine the peak system load, especially on hot summer days when residential air-conditioning use is high. Traditional building power profiles are changing. Currently, there is an increased use of energy-efficient building materials and designs, which decreases building loads. In addition, there is an increased adoption of rooftop solar photovoltaic (PV), which leads to bidirectional power flow and significant power ramps as PV output decreases in the late afternoon. Building power profiles are likely to change even more as residential energy storage products proliferate. Therefore, a better understanding of residential electricity demand is key to addressing the envisioned transition of the electric power system from its traditional structure to one that is transactive.
92 citations
TL;DR: A recent study conducted by the Council for Energy, Environment, and Water (CEEW) across six states (Bihar, Jharkhand, Madhya Pradesh, Uttar Pradesh, West Bengal, and Odisha) found that about 50% of the households had no electricity despite having a grid connection as discussed by the authors.
Abstract: It is well established that access to energy is closely linked with socioeconomic development. India houses the largest share of the world's population deprived of electricity with about 237 million people lacking access (International Energy Agency). At the same time, in India, many households that do have access to electricity lack an uninterrupted and quality power supply. A recent study conducted by the Council for Energy, Environment, and Water (CEEW) across six states (Bihar, Jharkhand, Madhya Pradesh, Uttar Pradesh, West Bengal, and Odisha), found that about 50% of the households had no electricity despite having a grid connection. This indicates that there is an immediate need to address the quality, affordability, and reliability of the power supply in addition to extending the grid footprint.
84 citations
TL;DR: In this article, the authors consider potential pathways for increased use of direct-current (DC) power distribution and identify those pathways that seem most beneficial and likely to succeed, and limit the scope of consideration to distribution within (or between) buildings.
Abstract: Direct-current (DC) power distribution has been used ever since electric grids were invented, but, for the last century, low-voltage dc has been largely limited to a variety of niche applications such as rail transport, vehicles, telecommunications, and off-grid buildings. Recent years have seen a variety of innovations in dc distribution technology, notably, standards for 380-V dc cabling and connectors and increases in power that can be carried over Ethernet and universal serial bus (USB). There are increasing calls for much more use of dc distribution and dc microgrids in buildings, and there are potential advantages of both. However, open questions remain about the directions this might take, what policy makers could and should do in this area, and technology developments that would be most useful. This article considers potential pathways for increased use of dc and identifies those pathways that seem most beneficial and likely to succeed. We limit the scope of consideration to distribution within (or between) buildings.
66 citations
TL;DR: In this article, the authors proposed to use reversible substations able to give back the dc energy surplus to the ac distribution system, which can also avoid the installation of reversible infrastructure, providing a high degree of controllability over the dc traction system voltage.
Abstract: The traditional concept of dc traction systems for light rail applications was based in a simple dc system that was fed by ac/dc noncontrolled diode rectifier substations connected to the ac distribution network. Low-energy efficiency and controllability were not a problem. However, with the massive implementation of regenerative braking technologies in light trains and trams, the development of an effective way to manage the recovered energy became an important issue. The regenerated power injected in the system by a train in braking mode could be used only in the case where another nearby train was in traction mode. Otherwise, the regenerated power was dissipated in the dc traction system or in the rheostatic braking equipment, decreasing the overall system energy efficiency. The need for more solutions that would allow more use of the regenerated energy and increased energy efficiency in the system was the driving force for new technological developments. First, proposals were for the use of reversible substations able to give back the dc energy surplus to the ac distribution system. Then, due to energy storage cost reductions, a combination of technologies such as insulated-gate bipolar transistor (IGBT)-based reversible substations with on-board and off-board accumulation systems evolved into a reality. The use of substation-level off-board accumulation systems can also avoid the installation of reversible infrastructure, providing a high degree of controllability over the dc traction system voltage. However, higher efficiency rates are achieved when the energy storage is installed on board. In such a case, the regenerated power is used in-situ, minimizing the transmission losses. One of the main benefits of the offboard accumulation approach is the fact that many trains equipped with regenerative braking systems can take advantage of a single device. On the other hand, the use of on-board accumulation leads us toward more flexible, efficient, and dependable systems. Therefore, some manufacturers are using these kinds of on-board accumulation systems to avoid the use of overhead line equipment and to reduce the visual impact, offering catenary-free solutions.
65 citations
TL;DR: The majority of rail networks across the world are nonelectrified as mentioned in this paper, and diesel-powered trains that require refueling stations and produce high noise levels and pollutant emissions, whereas high-speed trains are the fastest land passenger systems.
Abstract: Railways are a vital part of the world economy, transporting both goods and passengers. Freight trains transport large quantities of goods, whereas high-speed trains are the fastest land passenger systems. At present, the majority of rail networks across the world are nonelectrified. They run diesel-powered trains that require refueling stations and produce high noise levels and pollutant emissions. On the other hand, electrified railways have a network that directly supplies locomotives by pantographs or conducting shoes. Because electric trains do not carry the energy source on board, they can be lighter and more powerful. However, electric railways have higher initial capital and maintenance costs and are, therefore, economically justified only if the traffic on the line is substantial.
64 citations
TL;DR: In this article, the need for new grid services such as phase balancing and grid-edge reactive and voltage support is emerging, in addition to conventional feeder relief and protection schemes.
Abstract: Proliferation of renewable energy resources at bulk power and distributed energy resources (DERs) at distribution and prosumer/grid-edge levels give rise to power system operational issues for both transmission and distribution operators. At the bulk power/transmission operation level, these changes create the need for higher levels of ancillary services and new types of grid services (flexibility reserves, synthetic damping and inertia, etc.). At the distribution operation level, in addition to conventional feeder relief and protection schemes, the need for new grid services such as phase balancing and grid-edge reactive and voltage support is emerging.
52 citations
TL;DR: The need to mitigate climate change is driving efforts to make U.S. electric power generation cleaner, and this provides new impetus for improving the operating efficiency of buildings at scale and increasing the hosting capacity of distributed renewable generation.
Abstract: Buildings consume more than 30% of the total primary energy expended worldwide and contribute to a third of the world?s greenhouse gas (GHG) emissions. In the United States, buildings consume more than 40% of the total energy and contribute almost 38% of GHG emissions. In addition, the buildings in the United States consume more than 75% of the electricity generated. The need to mitigate climate change is driving efforts to make U.S. electric power generation cleaner, and this provides new impetus for improving the operating efficiency of buildings at scale and increasing the hosting capacity of distributed renewable generation. Because these renewable generation technologies are variable in nature, they create significant short- and long-term imbalances between supply and demand.
TL;DR: In this article, a coupled-inductor dc circuit breaker is demonstrated for fault protection in a notional dc microgrid, and it is shown that interfacing a wind power generator to a dc system is simpler than interfacing it to an ac system.
Abstract: Since the great debate between Thomas Edison and Nikola Tesla, our nation's power system has operated on alternating current (ac). This was chosen over direct current (dc) because of the need to increase voltage with ac transformers to a high value using transformers for long-distance power transmission. The system has served its purpose well, but now, many energy sources, such as solar panels, fuel cells, and batteries, supply dc voltage. Also, dc/dc power converters are commonly used to transform voltage and to interface these dc sources with a larger system. Because of this, local dc power systems (or microgrids) have become popular topics in research literature. It also turns out that interfacing a wind power generator to a dc system is simpler than interfacing it to an ac system because ac/dc conversion is needed for the former and ac/dc/ac conversion is needed for the latter. Although energy sources and power conversion are readily available for dc power systems, some highperformance applications require fast-acting dc circuit breakers, which are currently in the experimental phase. This article discusses options for high-performance dc circuit breakers and specifically details the coupled-inductor dc breaker. This breaker is demonstrated for fault protection in a notional dc microgrid.
TL;DR: The history of flying cars, including some of the ongoing development work, is described in this article, where the technical challenges, particularly related to lift and propulsion, and the problems related to wide-scale adoption are presented.
Abstract: Flying cars have always been an interest for development and commercialization throughout the history of automobiles and aircraft. In this article, the history of flying cars, including some of the ongoing development work, is described. The technical challenges, particularly related to lift and propulsion, and the problems related to wide-scale adoption are presented. With the advances in engines, electric motors, power converters, and communications, there is an increasing interest in flying vehicles and more electrification of these vehicles. This article also examines the challenges and requirements of developing a hybrid or a pure electric flying car, propulsion strategies for operation like an automobile and airplane, and vertical takeoff and landing (VTOL).
IBM1
TL;DR: TESs as discussed by the authors are a scalable, flexible approach to designing and implementing efficient, reliable, and resilient electrification systems, both large and small scale, and can be implemented within a single building or home, across a campus, or across an entire region.
Abstract: TESs are a scalable, flexible approach to designing and implementing efficient, reliable, and resilient electrification systems, both large and small scale. They can be implemented within a single building or home, across a campus, or across an entire region, as shown by previous demonstrations and current projects. Because of their ability to address both interoperability issues and optimization and management issues, they're an important technique for future electrification designs and will become even more practical as the process of understanding and assigning value to flexible DER and system objectives (both business and operational) matures. Ultimately, they should enable a broad range of operational, business, regulatory, and incentive models to be supported by future systems.
TL;DR: In this paper, the safe and uninterrupted operation of these microgrids against fault conditions is an important system requirement, and the authors propose a distributed energy management system for data centers and office buildings.
Abstract: Renewable power sources and other distributed energy resources (DERs), such as photovoltaics, wind, and battery storage, feed electricity to the utility grid and/or local loads through interfacing power electronic converters. The safe and uninterrupted operation of these microgrids against fault conditions is an important system requirement. Although alternating current (ac) is still the dominant form of electricity, direct current (dc) has been gaining traction in data centers and office buildings because it offers higher system efficiency, lower capital and operating expenses, and easier integration of renewable resources and DERs.
TL;DR: In this paper, the authors discuss the historical and current DOE research and development activities in this topic area, including a recent PNNL report concerning the valuation of transactive systems, including their simulation, standardization, theoretical principles, valuation, demonstration, and automation.
Abstract: About 11 years ago, the U.S. Department of Energy (DOE) funded the Pacific Northwest National Laboratory (PNNL) to conduct one of the first field demonstrations of what later was called a transactive system. Transactive systems have since become important tools in the DOE?s research efforts to modernize the U.S. electric power grid and conserve energy in U.S. buildings. The DOE currently funds fundamental and applied research to advance transactive system technologies, including their simulation, standardization, theoretical principles, valuation, demonstration, and automation. This article will discuss the historical and current DOE research and development activities in this topic area, including a recent PNNL report concerning the valuation of transactive systems.
TL;DR: In this paper, the authors argue that the flexibility and adaptability of the passenger's needs as part of solving the conundrum posed by the tension between capacity, energy use, and service level will be the drive for more innovation.
Abstract: Modern state-of-the-art railway investments around the globe are based on the steel-on-steel principle, and there is no reason to doubt this is, by and large, the rail travel of the future-as it was nearly 200 years ago. Electrification will continue to play a significant role as it always has, more so with the drive to reduce greenhouse gas emissions and the likelihood of the death of the diesel engine. This will provide a fresh opportunity to advance electrification systems around the world, which hopefully will make them more attractive financially. On other fronts, the flexibility and adaptability of the passenger's needs as part of solving the conundrum posed by the tension between capacity, energy use, and service level will be the drive for more innovation. Physical and virtual connectivity will be at the heart of how we will be traveling in the future, not just by rail.
TL;DR: The levelized cost of kerosene lighting can be two to five times more than more efficient energy sources as mentioned in this paper, with an energy cost between US$100 and US$200 per kWh, nearly 1,000 times the price of electricity in the United States.
Abstract: Almost 4 billion people around the world today live without reliable access to electricity, and about 1.1 billion have no access to electricity whatsoever. To cook meals and light homes, these people often resort to ad hoc energy solutions that provide only limited relief while presenting substantial drawbacks. Low-quality kerosene lamps common in remote, off-grid communities create air pollutants that damage human health and the environment. Further, the levelized cost of kerosene lighting can be two to five times more than more efficient energy sources. Worse yet are disposable single-cell batteries, with an energy cost between US$100 and US$200 per?kWh, nearly 1,000 times the price of electricity in the United States.
TL;DR: The Smart Grid Initiative as discussed by the authors is an initiative that calls for increased design, deployment, and integration of distributed energy resources, smart technologies and appliances, and advanced storage devices in the electric power grid.
Abstract: The 21st century electric power grid is transforming with an unprecedented increase in demand and increase in new technologies. In the United States Energy Independence and Security Act of 2007, Title XIII sets the tenets for modernizing the electricity grid through what is known as the ?Smart Grid Initiative.? This initiative calls for increased design, deployment, and integration of distributed energy resources, smart technologies and appliances, and advanced storage devices. The deployment of these new technologies requires rethinking and re-engineering the traditional boundaries between different electric power system domains (Figure 1).
TL;DR: Electric transportation systems have increased in complexity in several ways, for example, electrical performance has increased from what was traditionally the core of the system, a rolling stock and traction supply circuit, to a plethora of devices installed for signaling, communication, and control.
Abstract: Electric transportation systems have increased in complexity in several ways. For example, electrical performance has increased from what was traditionally the core of the system, a rolling stock and traction supply circuit. Today, a plethora of devices are installed for signaling, communication, and control, requiring a proportionally larger number of interconnecting cables; the reliability and availability of the system has increased, as has user and stakeholder awareness; and system assurance and safety go through a complex and sophisticated process.
TL;DR: The U.S. Army has been pursuing efforts to achieve better fuel economy in its ground vehicles to reduce the overall fuel-related logistic burden as well as enable cost savings as mentioned in this paper.
Abstract: The U.S. Army has been pursuing efforts to achieve better fuel economy in its ground vehicles to reduce the overall fuel-related logistic burden as well as enable cost savings. In military applications, depending on the destination to which fuel needs to be carried and the way it is carried (i.e., by ground, air, ship, etc.), the cost per gallon of fuel can be in the range of US$1,000 in certain cases (Tiron, 2009). This is a large expense, and there is always the motivation to improve fuel economy in the military. Among various activities to achieve the goal of fuel economy improvement, vehicle electrification is considered to be an important one and includes the introduction of hybrid and electric vehicles in the military. In addition, the army also needs high-voltage (HV) high-power electrical devices for nonvehicular applications, including but not limited to certain types of arms that can be electrified.
TL;DR: The Italian high-speed (HS) railway network consists of about 1,000 km of double track lines, and a new section of about 50 km will be put in service in 2016, and the main technical aspect related to more than ten years of experience in handling the boundary between different electric traction systems is referred to.
Abstract: The Italian high-speed (HS) railway network consists of about 1,000 km of double track lines. It is still growing, and a new section of about 50 km will be put in service in 2016. The HS railway network is broadly equipped, especially in the countryside, with a 2 ? 25 kV, 50 Hz electrification system, while in the urban areas as well as for the HS Rome-Florence line, a 3 kV direct current (dc) electrification system was adopted. The peculiarity of the Italian HS system is the high number of interconnections with the former railway network, called the conventional railway. Twenty double-track interconnections are currently in operation to manage many traffic routes. Since December 2005, when the first 2 ? 25 kV alternating current (ac) line was placed into service, the Italian railway infrastructure management has gained experience in managing the electrical interferences between the 3 kV dc and the 2 ? 25 kV ac electrification systems. This article refers to the main technical aspect related to more than ten years of experience in handling the boundary between different electric traction systems. Figure 1 gives an overview of the Italian HS network. For each line, the first year of service, the relevant electrification system, and the number of interconnections with the conventional railway network are given.
TL;DR: In this article, the focus of IEEE Electrification Magazine and of this article is on understanding and demonstrating how transactive energy systems can have an impact on non-bulk power applications.
Abstract: Okay, let's be honest-there's pretty much nothing on metaheuristics in this article other than one short section, so don't let the title distract you. The focus of this issue of IEEE Electrification Magazine and of this article is on understanding and demonstrating how transactive energy systems can have an impact on nonbulk power applications. So what does that include? Well, as it turns out, a lot. The bulk power system with its larger generators and high-voltage transmission lines requires lots of planning, investment, and maintenance. These are assets that have lives measured in decades, and much of their topology is relatively fixed. The bulk system is also well monitored and heavily networked, i.e., there are multiple paths for the electricity to flow, and therefore alternative paths for power flow in the event of a disturbance.
TL;DR: In this paper, it is shown that a stray current is the part of a current caused by a dc traction system that follows paths other than the return circuit, and the major effects of stray currents can be the corrosion and subsequent damage of metallic structures at the points where stray currents exit.
Abstract: It is well known that in dc-electrified rail lines, the running rails are used to return the traction current to the rectifier substations. However, we cannot avoid some part of this current leaving the rails and instead passing through the earth to rejoin the return circuit at a point that is closer to the rectifier substation, and so the current reaching the negative busbar of the rectifier substation. These leakages, called stray currents, seek the least-resistant paths and, in particular, piping and cable systems of any kind placed in the neighborhood of tracks. Thus, a stray current is the part of a current caused by a dc traction system that follows paths other than the return circuit. The major effects of stray currents can be the corrosion and subsequent damage of metallic structures at the points where stray currents exit. The metallic mass dissipated onto the soil can be estimated through the Faraday's laws of electrolysis. For example, considering 1 A of stray current flowing continuously through a steel structure, the metallic mass of corroded steel dissipated onto the soil is equivalent to 9.13 kg per year. There is also the risk of overheating, arcing, fire, and subsequent danger to people and equipment both inside and outside the dc traction system.
TL;DR: A recent report from Navigant Research showed that the direct-current (dc) product marketplace is expected to total US$33 billion between 2015 and 2024 in four key market segments: off-and bad-grid telecommunications, data centers, commercial buildings, and off-grid military operations as mentioned in this paper.
Abstract: With the advent of advanced power electronics, distributed renewable generation, and direct-current (dc)distribution, the power industry has been anticipating a massive revolution in the way power is used in the United States. Although this expected local shift has been gradual to date, it may be approaching quickly and quietly from the periphery. According to a recent report from Navigant Research, the dc product marketplace is expected to total US$33 billion between 2015 and 2024 in four key market segments: off- and bad-grid telecommunications, data centers, commercial buildings, and off-grid military operations. A similar developing trend is taking place in the microgrid market,where a study by Markets and Markets forecasts a US$35 billion annual marketplace by 2022.
TL;DR: A new industrial revolution is underway, driven by the integration of creative digital technologies into large-scale physical systems, creating intelligent systems that can operate more efficiently and improve quality of life.
Abstract: A new industrial revolution is underway, driven by the integration of creative digital technologies into large-scale physical systems, creating intelligent systems that can operate more efficiently and improve quality of life. The best-known example of such an intelligent system is the smart grid. The same technologies that enabled the smart grid are being applied to many other types of physical systems. Intelligent systems are rapidly emerging in transportation, buildings, other energy infrastructures (e.g., gas, oil, and water), manufacturing, emergency response, and health care. Of course, the smart grid provides an essential foundation since all types of intelligent systems depend on reliable and high-quality electricity to power their operation. Various writers use terms such as cyberphysical systems,” “industrial Internet,” and the “Internet of Things (IOT )” to refer to what we are calling “intelligent systems.” While these terms do not necessarily mean the same thing, they all bring to mind a common set of enabling technologies that are making physical systems intelligent.
TL;DR: The story of how 19 organizations, including major corporations, national governments, universities, and research institutions, collaborated on an ambitious research and development (R&D) project at the cutting edge of the Internet of Things (IoT) and how the results of that project can now help me find a bicycle to rent in La Coru?a, Spain, when it has been a long day and I am just too tired to walk anymore.
Abstract: This is the story of how 19 organizations?including major corporations, national governments, universities, and research institutions?collaborated on an ambitious research and development (R&D) project at the cutting edge of the Internet of Things (IoT) and how the results of that project can now help me find a bicycle to rent in La Coru?a, Spain, when it has been a long day and I am just too tired to walk anymore. Of course, if that were all it did, this would not be much of a story, but there is more.