Showing papers in "IEEE Power & Energy Magazine in 2007"

Energy hubs for the future

Abstract: This paper presents a project named "Vision of Future Energy Networks", which aims at a greenfield approach for future energy systems. The definition of energy hubs and the conception of combined interconnector devices represent key approaches towards a multicarrier greenfield layout. Models and tools for technical, economical and environmental investigations in multicarrier energy systems have been developed and used in various case studies

The ABCs of HVDC transmission technologies

Abstract: An overview of high voltage direct current systems and applications is presented in this paper. The favorable economics of long-distance bulk-power transmission with HVDC together with its controllability make it an interesting alternative or complement to AC transmission. The higher voltage levels, mature technology, and new converter designs have significantly increased the interest in HVDC transmission and expanded the range of applications

Predicting the Wind

Abstract: Due to increasing wind power penetration, the need for and usage of wind power prediction systems have increased. At the same time, much research has been done in this field, which has led to a significant increase in the prediction accuracy recently. With many ongoing research programs in the field of numerical weather prediction (NWP), as well as in the power output prediction models (transforming wind speed into electrical power output), one can expect further improvements in the future. For the time being, three measures are taken as best practices to reduce prediction errors: Combinations of different models can be done with power output forecast models as well as with NWP models (multimodel and multischeme approaches). Reductions in RMSE of up to 20% were shown with intelligent combinations. As expected, a shorter forecast horizon leads to lower prediction errors. However, the organization of the electricity market as well as the conventional generation pool has a large influence on the needed forecast horizon. The forecast error depends on the number of wind turbines and wind farms and their geographical spread. In Germany, typical forecast errors for representative wind farm forecasts are 10-15% RMSE of installed power, while the error for the control areas calculated from these representative wind farms is typically 6-7% and that for the whole of Germany only 5-6%. Whenever possible, aggregating wind power over a large area should be performed as it leads to significant reduction of forecast errors as well as short-term fluctuations. a large area should be performed as it leads to significant reduction of forecast errors as well as short-term fluctuations.

HVDC transmission: yesterday and today

Abstract: Basically, this paper takes a brief look at the history of HVDC to better understand its upcoming future. It also portrays some of the early developments in modern high-voltage direct current (HVDC) transmission. Today there are 16 DC links operating or under construction in the United States and 21 in North America. There are additionally numerous links throughout Scandinavia as well as in Japan, Australia, Brazil, South Africa, India, China, and others; well over 100 world wide. And, many others are planned, especially in India and China. HVDC transmission is an important contributor to successful power system operation. The history is interesting; after a period of comparative dormancy the future is unexpectedly bright

European Balancing Act

Abstract: Wind power integration into power systems has two dimensions: an economical one related to optimization of the resources and a fair sharing of the cost, and a technical one related to security of supply. The economical dimension is first observed in the allocation and use of reserves that can incur increased costs for the power system operation. The actual impact of adding wind generation in different balancing areas can vary depending on local factors. Comparing European studies, some general aspects to reduce integration costs were identified, such as aggregating wind plant output over large geographical regions, larger balancing areas, and operating the power system closer to the delivery hour. In regard to the technical dimension, appropriate grid codes, in particular FRT and frequency control requirements, are essential to allow high wind penetration levels (>15%).

Taking an active approach

Abstract: The United Kingdom is leading Europe in its power market reforms and is currently engaged in addressing issues of DG integration through development of innovative approaches to network planning, operation, regulation, and pricing. This article draws on these recent advances to explore active management technologies, developing regulatory arrangements for network operation, and new commercial opportunities emerging from the low-carbon climate change agenda. It explores the changing role of the distribution system operator (DSO) in response to increasing penetration of DG and identifies the transitions currently taking place in the United Kingdom toward integration of DG that has wider implications for extrapolation across Europe.

To Capture the Wind

Abstract: From the birth of modern electricity-generating wind turbines in the late 1970s to now, wind energy technology has dramatically improved. Capital costs have plummeted, reliability has improved, and efficiency has increased. High-quality turbine manufacturers exist around the world, and wind plants of 300 MW and larger are being integrated into the electrical grid to exacting utility specifications. These modern wind plants are now routinely produced by multinational manufacturing companies at a cost of energy approaching, and in some cases below, that of fossil-fuel generating plants. At the end of 2006, the total U.S. wind energy capacity had grown to 11,603 MW, or enough to provide the electrical energy needs of more than 2.9 million American homes. Wind capacity in the United States and in Europe has grown at a rate of 20% to 30% per year over the past decade. Despite this rapid growth, wind currently provides less than 1% of total electricity consumption in the United States. The vision of the wind industry in the United States and in Europe is to increase wind's fraction of the electrical energy mix to more than 20% within the next two decades.

Accommodating wind's natural behavior

Abstract: Integration of wind-power plants into the electric power system presents challenges to power-system planners and operators. These challenges stem primarily from the natural characteristics of wind plants, which differ in some respects from conventional plants. Wind plants operate when the wind blows, and their power levels vary with the strength of the wind. Hence, they are not dispatchable in the traditional sense, which lessens the ability of system operators to control them while maintaining the system's balance between load and generation.

Probabilistic Transmission Planning

Abstract: Probabilistic transmission planning has become increasingly necessary and important in recent years. Some utilities like British Columbia Transmission Corporation (BCTC) have started their practice toward this direction. This article addresses basic aspects of probabilistic transmission planning. The probabilistic method is not intended to replace the deterministic criterion but adds one more dimension to enhance the transmission planning process. An actual example at BCTC is provided to demonstrate the application of probabilistic transmission planning.

Engineering perspectives on IEC 61850

Abstract: The aim of this paper is to discuss the benefits as well as the necessary changes linked to this substation automation communication technology. More specifically, this paper addresses the evolutions to be done during system engineering in order to properly use the capabilities of the IEC 61850 toolbox. As per any tool there is a need to know how to properly use it and to fully understand its limits

Delivering accurate and timely data to all

Abstract: This paper discusses a model-based substation automation application for advanced data availability. The SuperCalibrator concept provides a basic technology to filter all substation data that are readily available by the substation automation scheme. The SuperCalibrator is conceptually very simple. It is a state estimator using a detailed three-phase breaker-oriented instrumentation-inclusive substation model. As such, the errors introduced by the instrumentation are compensated and the estimated values are closer to the actual values of the electric power system. The overall methodology identifies bad data and wrong topologies and quantifies the quality of the filtered data expressed in terms of the expected error in this data. Substation automation enables the seamless implementation of the SuperCalibrator. In turn, the SuperCalibrator substantially contributes toward the promise of substation automation to reliably provide accurate data to all clients. The applications discussed in this article should ignite the dialog and the realization that substation automation can make it possible to dramatically improve our approaches and tools in monitoring, controlling, and protecting the electric power grid infrastructure.

What Comes First

Abstract: Wind power is a mature participant in the power grids of Europe. In North America, however, wind power is still a small player but growing rapidly. As such, power grid operators in North America are just beginning to learn how to incorporate wind power into transmission grids and how to manage the variable power output of wind plants. The challenge for wind energy transmission can be viewed as a "chicken and egg" situation. Transmission owners are not currently able to build new high-voltage transmission lines to remote areas where there may be a high potential wind energy resource but little existing generation or load. Bottlenecks in high-load corridors typically have priority for the limited funds available for building new transmission lines. Wind plant developers, as a result, are not able to build new wind power plants in remote wind-rich areas unless there is a transmission line capable of transferring the plant output to major load centers. So today, wind developers find it necessary to locate wind plants in less-attractive wind regions that are closer to existing transmission lines with available capacity.

Queuing Up

Abstract: The interconnection queue is the mechanism for grouping and ordering prospective generation projects for evaluating impacts on the bulk system. These days, with record-setting installations of wind generation capacity in the United States, it is difficult to find an interconnection queue that does not contain at least some wind generation projects; in the areas of the country with good or better wind resources, there may be dozens of prospective projects awaiting study. The result has been a much broader exposure within the electric power engineering community to the technical issues and challenges associated with wind generation.

Fuel cells and load transients

Abstract: Fuel cells are static energy conversion devices that convert the chemical energy of fuel into electrical energy directly. Compared with conventional power generation systems, they have many advantages, such as high efficiency, zero or low emission (of pollutant gases), and flexible modular structure. Fuel cells are expected to play an important role in future distributed generation (DG) applications. Fuel cell DGs (FCDGs) can either be connected to a utility grid for network reinforcement or installed in a remote area to supply stand-alone power. In this article, a load transient mitigation controller is described for hybrid PEMFC-battery power generation systems. The hybrid FCDG is controlled in a way that during a load transient, the fuel cell provides the steady-state part of the load, and the battery will supply the transient part of the load. The proposed technique can be especially useful in fuel cell vehicles (motor starting and accelerating) as well as in stationary applications, where load transients are unavoidable. The load transient mitigation controller is applicable to other types of FCDGs

Planning to expand

Abstract: The appropriate functioning of the transmission network of an electric energy system is critical for an electricity market to thrive. Moreover, since the annual cost (investment and operation) of a transmission network is a small percentage of the cost of the energy (and ancillary services) traded throughout the year in the market, and since a transmission problem might have dramatic effects on trade disruption, a well-managed and properly planned transmission network is a key requirement in a well-designed electricity market. The paper describe the authorspsila view of the fundamental ingredients of transmission expansion planning within the framework of an electricity market including competitive generating companies and competitive load-serving entities as well as independent producers and consumers. It was assumed the transmission network to be a centrally managed entity pursuing maximum social welfare. The paper illustrates the transmission expansion planning methodology using the transmission network of mainland Spain, managed by Red Electrica de Espantildea (REE), the transmission system operator (TSO) of the electricity market of mainland Spain (EMMS). It should be noted that REE is also the system operator of this market.

Pacific HVDC intertie

Abstract: Although not the first HVDC transmission scheme, the Pacific HVDC Intertie (PDCI) has been the subject of keen interest from the HVDC community from its earliest days. The initial configuration has been repeatedly altered over a period of more than 30 years as a result of various upgrades and in response to two major earthquakes, a fire, and environmental concerns. Once a museum of HVDC technology development, the PDCI now contains the most modern equipment available. The owners of the southern converter station at Sylmar, California, have completely rebuilt the station, replacing nearly all of the converter equipment with modern high-power converters. At the northern end of the Intertie, at the Celilo converter station in The Dalles, Oregon, the changes have been more modest. This article traces the story of the creation of the PDCI and the subsequent changes that have taken the capacity from 1,440 MW in 1970 to 3,100 MW today

Electricity restructuring [Business Scene]

Abstract: The Islamic Republic of Iran currently manages an electricity sector with about 40,000 MW of installed capacity, which serves more than 13 million end users through a 36,000-km high-voltage transmission interconnected grid and a more than 50,000-km medium-voltage distribution network. This fairly large power system with an annual peak demand growth rate of about 10%, one of the highest rates in the world, makes the movement toward restructuring the electricity industry of Iran unavoidable, mainly for two reasons: 1) it is expected that the restructuring and consequently the privatization would improve the performance and efficiency of the present industry 2) it is expected that the development of a new competitive paradigm in the electricity industry could make the sector more attractive for potential independent investors. Based on these ideas, the restructuring studies primarily were begun in early 1990. The studies had two main directions: providing legal foundations and determining the main implementation steps. This article discusses these two directions

Toward effective substation automation

Abstract: Integrating IEC61850 at TVA's Bradley substation for protection, SCADA, and enterprise applications substation, and enterprise applications. The IEC 61850 standard provides the means to integrate communications, information, and applications into a coherent, flexible, very powerful framework for the secondary system. With its deployment, more information can be exchanged and more applications can be run. And we shall see that integrated, accessible information is truly the enabler of effective and economic substation automation

Planning for Big Things in Brazil

Abstract: This paper discusses the planning and building of large-scale transmission networks in competitive hydrothermal systems. The business model for transmission expansion in Brazil relies on a combination of planning and competition. The model is felt to be successful both in terms of ensuring expansion and attracting private investments and is being considered by other Latin American countries, mainly Central America and the Andean market. Due to new transmission facilities the interchange capacity limits in between regional systems have increased, avoiding congestion risks, enhancing the system security margins, and giving more transmission capacity to accommodate the needed power flows to optimize the hydrothermal dispatch. Regulatory risks have also been low, since regulations in place are almost consolidated and considered stable by market players. However, some challenges remain to be tackled, essentially concerning the strong coupling between generation and transmissiori planning and transmission tariff allocation. Additionally, it must be mentioned that improvement of the regulatory framework for the transmission and distribution frontier is a topic that is being currently focused on by the regulator. Clearly, setting the rules for system reinforcement in this interface area has been proved to be highly relevant in not jeopardizing the reliability of load supply.

Get on the digital bus to substation automation

Abstract: This paper presents next-generation measuring systems with a real-time Ethernet process bus. Digital communication has proven its advantages in high voltage substations from bay control and protection up to the telecommunication interface. The enlarged digital area in substations offers wide ranges and easy adjustment of parameters for in improved fitness of the investment for future demands.

Understanding Electric Utilities and Deregulation, Second Edition [Book Review]

Abstract: This book is part of the Taylor & Francis (formerly Marcel Dekker) Power Engineering Series. It updates the first, released in 1999, to reflect subsequent developments in deregulation and to include new material on blackouts, service reliability, and issues of dealing with an aging physical infrastructure. The book provides good descriptions of the power system, the technologies, and the layers in the transmission and distribution network that deliver the power to the customer. It also provides good discussions on renewable technologies, distributed generation technologies, and the rationale and practice of utility regulation the 1980s and 1990s. The text's treatment of deregulation is a disappointment, with dated material and a lack of coverage on critical deregulation issues on the table today. The book concludes with a strong discussions about maintaining reliability in an aging distribution system and of the nature and causes of blackouts. The book is recommended for people new to the field and for visitors from abroad to help them understand electrical power systems.

Early three-phase power [History]

Abstract: The early decades of what became known as the "Electric Age" were marked by the efforts of outstanding engineers, inventors, and entrepreneurs on both sides of the Atlantic Ocean to develop a power supply system to best meet electrical generation, transmission, distribution, and customer utilization requirements. This article is a fascinating account of the development and evolution of alternating current (ac) and polyphase systems with special emphasis on the development of three-phase ac power, the prevailing system that today enjoys worldwide use.

Building a plan for HVDC

Abstract: Large amounts of study, modeling, and planning are necessary prior to the successful construction and integration of an HVDC facility. Feasibility studies are first conducted to determine the need for network controllability, necessary for ensuring system security, transmitting power over long distances, or interconnecting asynchronous systems. This planning and integration process has produced successful results in three HVDC installations in the northeastern United States, which are discussed in this article. The article also presents several examples of plans for HVDC expansion in the Western interconnection

Alternative energy sources in the Amazon

Abstract: This paper discusses the evaluation of energy potential of palm oil for the generation of electricity in isolated communities. In Brazil, the energy sector culture has historically been directed almost exclusively toward major projects geared to meet the demands of those sectors of society that have the greatest economic and political influence. Prioritizing industrialization and an accelerated urbanization, they have oriented the national energy system toward centralized production of enormous blocks of energy adapted to meet major urban concentration consumption but incapable of satisfying the needs of a large part of the population that inhabits the rural areas. These small- and medium-sized communities are sometimes isolated from the developed urban centers and not connected to the conventional electricity networks. In this scenario, the Amazon region stands out due to its huge territorial extension and low demographic density, which is scattered among islands and other locations not easily accessible. As a rule, these areas lack electricity, and, when they do have it, supply is precarious and provided through fossil fuels for electricity production

Scrutiny of the Iranian National Grid

Abstract: This article describes the events and phenomena that could lead to grid blackouts. The Iranian national grid experienced major system blackouts in 2001 and 2002. It was decided to study and analyze these system collapses, and a brief report about these disturbances is provided. Some suggestions and solutions are also given that could decrease the chance of system collapse after occurrence of a major fault. Upgrading existing protective systems to meet network protection criteria, eliminating some insecure protective functions, revising power swing blocking schemes, wider use of pilot protective schemes, applying adaptive relays and schemes and revising system relay settings are among the solutions suggested to improve the system performance during abnormal events and conditions

The true vision of automation

Abstract: This paper presents to help appreciate how much substation automation has become a part of the lexicon. The concept it represents is realizing all the benefits that digital technology can bring to the substation. The Michigan substation is meant to realize the organic implementation of automation technologies. It reflects how a system would evolve around these technologies as opposed to having substation automation added to a system. This substation was an attempt at realizing the vision of automation

Chinese growing pains

Abstract: China's economy has increased significantly, the annual average increase in gross domestic product (GDP) is more than 8% since 1978. With the sustained economic growth, the living standards of most people have improved, and more and more people have moved from rural areas to urban areas. In the long term, the extraordinarily high GDP growth drives China's increasing consumption of electricity. The urbanization requires high-quality and more reliable electric power supply. In China, the discussions on distribution systems are mainly about the power distribution systems for urban areas (called an urban distribution network in Chinese). In this paper, we will focus on the distribution systems in urban areas in China.

Many states of distribution

Abstract: The electric distribution system in the United States is celebrating over 125 years of design, development, expansion, and evolution. During that time, thousands of utilities that sprung up across the country met their customer's needs with many different types of system configurations, frequencies, and line voltages. Today, these systems serve nearly 138 million customers that use 3.66 trillion kWh. This article provides a brief synopsis of the prevalent distribution systems in use today. Of necessity, it must omit discussion of many of the types of systems that remain from those historical beginnings. In no way is this meant to diminish the importance, efficacy, or adequacy of those systems that currently satisfy customers' needs that are not described herein.