Power Electronics and Power Systems – serie

Sustainable energy services to customers - a balanced choice and coordination of energy generated by traditional and alternative sources - are the subject of this new innovative book. The myriad factors involved in modeling an effective sustainable power system are overwhelming. The “Green Islands” project represents a decade of work by over a dozen researchers who have developed a model designed to utilize the potential of distributed clean resources. The key is the proper use of Information Technology (IT). Sited on two islands in the Azores, the project developed the model of careful forecasting of demand and supply, down to the minute, coordinating the output of conventional power plants, wind energy, fly wheels, hydroelectricity, demand reduction, and even plug-in electric vehicles to take full advantage of the clean resources available. The energy contingencies of the remote islands are not unique. The issues of integrating promising clean technologies, such as wind, into a complex power grid are challenging in geographically far-flung, island-scale, power systems. Model-based sensing, communications, and decision-making algorithms to coordinate adaptive load management (ALM) could enable customers to utilize just-in-time (JIT), just-in-place (JIP), and just-in-context (JIC) energy resources. The distribution of flexible and efficient energy to customers is the goal. The model the authors have developed could change the way power portfolios are built. A new perspective for optimization of green energy is presented in this book. Additional data provided online via Springer represents a repository of real-world electric energy systems and its IT-enabled smarts.

Applied Mathematics for Restructured Electric Power Systems: Optimization, Control, and Computational Intelligence consists of chapters based on work presented at a National Science Foundation workshop organized in November 2003. The theme of the workshop was the use of applied mathematics to solve challenging power system problems. The areas included control, optimization, and computational intelligence. In addition to the introductory chapter, this book includes 12 chapters written by renowned experts in their respected fields. Each chapter follows a three-part format: (1) a description of an important power system problem or problems, (2) the current practice and/or particular research approaches, and (3) future research directions. Collectively, the technical areas discussed are voltage and oscillatory stability, power system security margins, hierarchical and decentralized control, stability monitoring, embedded optimization, neural network control with adaptive critic architecture, control tuning using genetic algorithms, and load forecasting and component prediction. This volume is intended for power systems researchers and professionals charged with solving electric and power system problems.

Robust Control in Power Systems deals with the applications of new techniques in linear system theory to control low frequency oscillations in power systems. The book specifically focuses on the analysis and damping of inter-area oscillations in the systems which are in the range of 0.2-1 Hz. The damping control action is injected through high power electronic devices known as flexible AC transmission system (FACTS) controllers. Three commonly used FACTS controllers: controllable series capacitors (CSCs) controllable phase shifters (CPSs) and static var compensators (SVCs) have been used in this book to control the inter-area oscillations. The overview of linear system theory from the perspective of power system control is explained through examples. The damping control design is formulated as norm optimization problem. The H_infinity, H2 norm of properly defined transfer functions are minimized in linear matrix inequalities (LMI) framework to obtain desired performance and stability robustness. Both centralized and decentralized control structures are used. Usually the transmission of feedback signal from a remote location encounters delays making it difficult to control the system. Smith predictor based approach has been successfully explored in this book as a solution to such a problem.Robust Control in Power Systems will be valuable to academicians in the areas of power, control and system theory, as well as professionals in the power industry.

Digital Control of Electrical Drives offers insight into electric drives and their usage in motion control environment. It provides links among electrical machine and control theory, practical hardware aspects, programming issues, and application-specific problems. The book prepares the reader to understand the key elements of motion control systems, analyze and design discrete-time speed and position controllers, set adjustable feedback parameters, and evaluate closed-loop performances. Basic engineering principles are used to derive the controller structure in an intuitive manner, so that designs are easy to comprehend, modify, and extend.Digital Control of Electrical Drives helps the reader acquire practical skills in designing discrete-time speed and position controllers. Each chapter is followed by a set of Matlab® and Simulink® tools which help readers master the phases of design, tuning, simulation, and evaluation of discrete time controllers, and foresee the effects of control solution on the overall motion control system. Readers will also understand the present performance limits of digital motion controllers.

Presenting the continuation and bifurcation-based approaches to assess power system voltage stability, this self-contained manual first provides basic definitions related to voltage stability based on IEEE/CIGRE voltage stability classification. Then the need for robust numerical techniques that are needed to address various aspects of voltage instability is articulated. It presents a tutorial introduction to the basic concepts in bifurcation theory and continuation methods. These methods lead to robust numerical techniques for voltage stability study. The book also provides details related to continuation power flow. In addition, it provides the approach to trace voltage stability boundary for changing system conditions and proposes a uniformed framework that provides computational approaches for both short-term and long-term voltage stability phenomena.

In this book, principles of the current injection are discussed first. This discussion is followed by an analysis of various magnetic current injection devices. The third harmonic current injection is discussed next, and several current injection networks are analyzed. The optimal current injection is the topic that follows, and the requirements imposed to the current injection network in order to provide the optimal current injection are derived. Several current injection networks that provide the optimal current injection are proposed, and some parasitic effects are discussed. Recovery of the power taken by the current injection networks is analyzed, and two types of passive resistance emulators are analyzed in detail, the current-loaded resistance emulator, and the voltage-loaded resistance emulator. Avoiding the inductor of the current injection network results in mutipulse operation of the current injection based rectifiers with passive resistance emulators, which is discussed next. In a separate chapter, a different current injection device based on three bi-directional semiconductor switches is presented, and previously derived results are generalized for this special type of current injection device. At last, the results are generalized to three-phase full-bridge thyristor rectifiers.Essentially, the book presents digested results of numerous research papers published in the last fifteen years in the area of current injection based rectifiers.The book may be of interest for the people involved in design of low-harmonic three-phase rectifiers, and the people involved in research in this area.

Voltage Stability of Electric Power Systems presents a clear description of voltage instability and collapse phenomena.

The text provides in-depth coverage of power system operation in the deregulated electricity market environment. Basic principles of power system operation and economics have been discussed with an emphasis on research in the area. Other features include coverage of a wide spectrum of issues such as: the role of the ISO in pool type vis-a-vis the bilateral markets; generation scheduling in deregulation; transmission pricing; congestion management; ancillary services management; reliability in deregulated power systems; and voltage dips and other power quality issues. A highlight of the book is the extensive coverage and country specific information provided on various operational aspects of restructured power systems worldwide. It presents a discussion of restructured electricity markets that have been established in various degrees and forms in many countries. This book comes at a time when the deregulation process is poised to undergo further rapid advancements. It is envisaged that the reader should benefit by way of an enhanced understanding of power system operations in the conventional vertically integrated environment vis-a-vis the deregulated environment.

The challenges facing participants in competitive electricity markets are staggering: high price volatility introduces significant financial risk into an industry accustomed to guaranteed rates of return, while illiquid forward markets prevent effective hedging strategies from being implemented. This title examines the unique properties which separate electricity from other traded commodities, including the lack of economical storage, and the impact of a scarce transmission network. The authors trace the sources of uncertainties in the price of electricity to underlying physical and economic processes, and incorporate these into a bid-based model for electricity spot and forward prices. They also illustrate how insufficient market data can be circumvented by using a combination of price and load data in the marking- to-market process. The model is applied to three classes of problems central to the operation of any electric utility or power marketer; valuing generation assets, formulating dynamic hedging strategies for load serving obligations, and pricing transmission contracts and locational spread options.Emphasis is placed on the difference between trades which can be "booked out" in the forward markets, and those which must be carried through to delivery. Lately, significant attention has been given to the role of regulators in mitigating excessive price levels in electricity markets. The authors conduct a quantitative analysis of the long-term effects of regulatory intervention through the use of price caps. By modeling the dynamic interplay between the observed price levels and the decision to invest in new generation assets, it is shown how such short term fixes can lead to long term deficits in the available generation capacity, and ultimately to market failures and blackouts.

An introduction to algorithms for improving the economic posture of a utility company in a restructured power system by promoting cost-effective maintenance schedules, the text offers a logical alternative to traditional electric utility maintenance practices and a basis for making maintenance decisions. Maintenance scheduling problems are formulated as decomposed problems. This signifies the nature of restructured power systems with self-interested entities and optimizes potential revenues while meeting constraints such as fuel schedules, emission constraints, hourly load demands, and network limits. Co-ordination of short and long-term maintenance scheduling is also presented. The book shows by numerous derivations and examples that careful planning and good co-ordination among self-interested entities in restructured power systems are essential to achieving an optimal trade-off between the cost of maintenance and service reliability. "Maintenance Scheduling in Restructured Power Systems" includes a variety of models, solutions and ideas that should be of interest to engineers, consultants, manufacturers, students, and others working and studying in the utility field.

This monograph is devoted to a hybrid-direct temporal method called SIME (for Single Machine Equivalent). SIME processes temporal information about the multimachine system dynamics to assess and control any type of transient instabilities under any type and model of power systems. Two approaches may be distinguished depending upon the source of information used: "Preventative SIME" which relies on a time-domain program to simulate anticipated contingencies, and "Emergency SIME" which uses real-time measurements. Preventative SIME mainly comprises two techniques: contingency filtering, ranking, and assessment; and (simultaneous) stabilization of harmful contingencies. The resulting preventative transient stability assessment and control (TSA&C) software can be used in all application contexts of transient stability studies. In a control center, for instance, its computational performances enable it to cope with very stringent requirements of real-time operation. Besides, interfacing SIME with an OPF algorithm allows combining transient stability constraints with specifics of the liberalized electricity market.Emergency SIME is a novel closed-loop control technique which contains the transient instabilities caused by contingencies' actual occurrence. It relies on real-time measurements to predict (the size of) instability and, accordingly, to design and trigger control actions able to impede system loss of synchronism. Emergency SIME is particularly suitable for protecting important generation sites and can complement preventative SIME. Both approaches rely on the same principles and basic software which yields a comprehensive and unified approach to TSA&C. The design of near optimal control techniques is a major asset of this software. This book provides extensive illustrations on a variety of power systems ranging from a simple 3-machine test system to real-world power systems comprising up to 627 generators and 4112 busses. This work should be especially helpful to researchers, utility engineers, and software designers and developers who are developing various types of transient stability software packages.

Automatic learning is a complex, multidisciplinary field of research and development, involving theoretical and applied methods from statistics, computer science, artificial intelligence, biology and psychology. Its applications to engineering problems, such as those encountered in electrical power systems, are therefore challenging, while extremely promising. More and more data has become available, collected from the field by systematic archiving, or generated through computer-based simulation. To handle this increase in data, automatic learning can be used to provide systematic approaches, without which the increasing data amounts and computer power would be of little use. This text is dedicated to the practical application of automatic learning to power systems. Power systems to which automatic learning can be applied are screened and the complementary aspects of automatic learning, with respect to analytical methods and numerical simulation, are investigated.The book presents a representative subset of automatic learning methods - basic and more sophisticated ones - available from statistics (both classical and modern), and from artificial intelligence (both hard and soft computing). The text also discusses appropriate methodologies for combining these methods to make the best use of available data in the context of real-life problems. It should be a useful reference source for professionals and researchers developing automatic learning systems in the electrical power field.

Voltage Stability of Electric Power Systems presents a clear description of voltage instability and collapse phenomena. It proposes a uniform and coherent theoretical framework for analysis and covers state-of-the-art methods. The book describes practical methods that can be used for voltage security assessment and offers a variety of examples. This is a first attempt to condense the technical papers and reports on this subject into a single, coherent, and theoretically sound presentation.Transmission, generation, and load aspects of the voltage instability problem are treated in detail, and a comprehensive power system model for use in voltage stability analysis is developed and explained. Notions and concepts from nonlinear system theory are presented in a tutorial manner for the use of those new to the field. Loadability, sensitivity, and bifurcation analysis of voltage stability are introduced and treated in depth. Voltage instability mechanisms are classified and minutely examined, together with the countermeasures that can be used to avoid them. In addition, voltage security criteria and methods are reviewed, analyzed and illustrated through realistic computer results.Voltage Stability is a relatively recent and challenging problem in Power Systems Engineering. It is gaining in importance as the trend of operating power systems closer to their limits continues to increase.

The advent of low temperature superconductors in the early 1960's converted what had been a laboratory curiosity with very limited possibilities to a prac­ tical means of fabricating electrical components and devices with lossless con­ ductors. Using liquid helium as a coolant, the successful construction and operation of high field strength magnet systems, alternators, motors and trans­ mission lines was announced. These developments ushered in the era of what may be termed cryogenic power engineering and a decade later successful oper­ ating systems could be found such as the 5 T saddle magnet designed and built in the United States by the Argonne National Laboratory and installed on an experimental power generating facility at the High Temperature Institute in Moscow, Russia. The field of digital computers provided an incentive of a quite different kind to operate at cryogenic temperatures. In this case, the objective was to ob­ tain higher switching speeds than are possible at ambient temperatures with the critical issue being the operating characteristics of semiconductor switches under cryogenic conditions. By 1980, cryogenic electronics was established as another branch of electric engineering.

The restructuring of the power industry has already begun and will be fully implemented in the United States and many other countries by the beginning of the 21st century. Unlike other sectors of the economy, restructuring of the utility industry requires a careful analysis because of the nature of the real-time operations. This book attempts to address the problems inherent in such a task in a coherent manner. The topics discussed include evolving market structures, mechanisms for implementation of the market requests, price incentives and transaction adjustments, and secure and optimal operation of the system under open access. Many technical, economic and regulatory questions related to making services market-based are addressed, and transmission provision-related market power problems are analyzed in detail. This text should be a useful resource for power systems engineers, educators, system operators, managers, planners and researchers working in the field.

This text presents comprehensive mathematical models of turbine-generators, HVDC and FACTS controllers, and small signal analysis of SSR. The emphasis is on the analysis using linearized models. Both damping torque and eigenvalue analysis are covered. Also included are the basic concepts of SSR interactions with fixed series compensation, PSS, HVDC, and FACTS controllers. Timely treatment has been given to the development of electrical analogue for the rotor system, the derivation of the network equations based on circuit topology and immittance functions using D-Q variables. The material is supported by several illustrative examples and case studies based on IEEE benchmark models.

This text outlines the application of auction methods for all aspects of power system operation, primarily for a competitive environment. A complete description of the industry structure, as well as the various markets is given. A thorough introduction to auction basics is included to explain how auctions have grown in other industries. Auction methods are compared to classical techniques for power system analysis, operations, and planning. The traditional applications of economic dispatch, optimal power flow and unit commitment are compared to auction mechanisms. Algorithms for auctions using linearized power flow equations, DC power flow equations, and AC power flow equations are included. The bundling of supportive services, known as ancillary services within the United States, is discussed. Extensions to the basic auction algorithms for inclusion of supportive services, as well as algorithms for scheduling and bidding on generation for GENCOs or independent power producers are presented. It provides an introduction to how electricity will be traded as a commodity in the future.

This work provides a comprehensive introduction to the topic of state estimation at an advanced textbook level. The theory as well as practice of weighted least squares (WLS) is covered, and it includes an in depth analysis of power flow basics, proper justification of Stott's decoupled method, observability theory and matrix solution methods. In terms of practical application, topics such as bad data analysis, combinatorial bad data analysis and multiple snap shot estimation are covered. The book caters both to the specialist as well as the newcomer to the field. State estimation should play a crucial role in the emerging scenario of a deregulated power industry. Many market decisions could be based on knowing the present state of the system accurately. The book crystallizes 30 years of WLS state estimation theory and practice in power systems and focuses on techniques adopted by state estimation developers worldwide. The book also reflects the experience of developing industrial-grade state estimation software that is used in the USA, South America, and many other places in world.

The era of the personal computer has, without doubt, permanently altered our life style in a myriad of ways. The "brain" of the personal computer is the microprocessor (together with RAM and ROM) which makes the decisions needed for the computer to perform in the desired manner. The microprocessor continues to evolve as increasingly complex tasks are required. While not sharing the limelight of the microprocessor, the "heart" of the personal computer, namely the power supply, is equally important since without the necessary source of power the microprocessor would be a useless piece of silicon. The power supply of twenty years ago was much different than its modem day equivalent. At the dawn of the personal computer era in the late 1970s, de power was obtained from a simple diode bridge. However, the need for smooth, regulated DC at low voltage required at the same time both a bulky input transformer and a large dc side ftlter. Those computer fans present at the birth of this industry can remember the large boxes housing our Altair, Cromemco and Northstar computers which was made necessary largely because of the huge power supply. It is not well appreciated but certainly true that the huge sucess of the Apple II computer in those days was due, at least in part, to the relatively slim proftle of the machine. This sleek appearance was largely due to the adoption of the then new and unproven switched mode power supply.

This research monograph is in some sense a sequel to the author's earlier one (Power System Stability, North Holland, New York 1981) which devoted cons- erable attention to Lyapunov stability theory, construction of Lyapunov fu- tions and vector Lyapunov functions as applied to power systems. This field of research has rapidly grown since 1981 and the more general concept of energy funct ion has found wide spread application in power systems. There have been advances in five distinct areas (i) Developing energy functions for structure preserving models which can incorporate non-linear load models (ii) Energy fu- tions to include detailed model of the generating unit i. e. , the synchronous machine and the excitation system (iii) Reduced order energy functions for large scale power systems, the simplest being the single machine infinite bus system (iv) Characterization of the stability boundary of the post-fault stable eQui- brium point (v) Applications for large power networks as a tool for dynamic security assessment. It was therefore felt appropriate to capture the essential features of these advances and put them in a somewhat cohesive framework. The chapters in the book rough ly fo llow this sequence. It is interesting to note how different research groups come to the same conclusion via different reas- ings.

"Industrial Energy Management: Principles and Applications" provides an overall view of the energy management approach by following the stream of energy from factory boundaries to end users. All topics are examined from the point of view of plant users rather than from that of designers and only the basic concepts necessary to clarify the operation of the plants are outlined. The book is written both as a textbook for university courses in engineering and as a work of reference for professionals in energy management. Readers are assumed to have a basic knowledge of thermodynamics, heat and mass transfer, electric systems and power electronics, as well as computer programming. The text can be used not only by technicians involved in the field of energy management, but also by managers who may find it a useful tool for understanding investment proposals and even a spur to solicit new ones.

The Field Orientation Principle (FOP) constitutes a fundamental concept behind the modern technology of high-performance, vector-controlled drive systems with AC motors. The recent interest in these systems has been spawned by the widespread transition from DC to AC drives in industry. Induction motors, industry's traditional workhorses, are particularly well suited for FOP-based vector control. This text presents the FOP in a simple, easy-to-understand framework based on the space-vector dynamic model of the induction machine. Relationships between the classic phasor equivalent circuits of the motor and their vector counterparts are highlighted. A step-by-step derivation of dynamic equations of the motor provides a formal background for explanation of the basic approaches to vector control. In addition, the author presents scalar control methods for low-performance drives as an intermediate stage between uncontrolled and high-performance drives.The reader will also find a full chapter devoted to power inverters, which constitute an important component of adjustable speed AC drive systems, and a review of associated issues such as observers of motor variables, parameter estimation, adaptive tuning, and principles of the position and speed control of field-oriented induction motors. Numerical examples and computer simulations illustrate the ideas and techniques discussed. This text is a practical resource and should be a useful for researchers and students interested in motor control, power and industrial electronics, and control theory.

In this text, the author covers two-dimensional analysis, emphasizing the use of finite elements to perform the most common calculations required of machine designers and analysts. The book explains what is inside a finite element program, and how the finite element method can be used to determine the behaviour of electrical machines. The methods described have been used in the design and analysis of most types of rotating and linear machines.

There is a need for fundamental changes in the ways society views electric energy. Electric energy must be treated as a commodity which can be bought, sold, and traded, taking into account its time-and space-varying values and costs. This book presents a complete framework for the establishment of such an energy marketplace. The framework is based on the use of spot prices. In general terms: o An hourly spot price (in dollars per kilowatt hour) reflects the operating and capital costs of generating, transmitting and distributing electric energy. It varies each hour and from place to place. o The spot price based energy marketplace involves a variety of utility-customer transactions (ranging from hourly varying prices to long-term, multiple-year contracts), all of which are based in a consistent manner on hourly spot prices. These transactions may include customers selling to, as well as buying from, the utility. The basic theory and practical implementation issues associated with a spot price based energy marketplace have been developed and discussed through a number of different reports, theses, and papers. Each addresses only a part of the total picture, and often with a somewhat different notation and terminology (which has evolved in parallel with our growing experience). This book was xvii xviii Preface written to serve as a single, integrated sourcebook on the theory and imple­ mentation of a spot price based energy marketplace.

We are very pleased to be asked to co-author this book for a variety of reasons, one of which was that it gave us further opportunity to work together. The scope proposed was very wide with the only significant proviso being that the book should be in a mongraph-style and not a teaching text. This require­ ment has given us the opportunity to compile a wide range of relevant material relating to present-day knowledge and application in power system reliability. As many readers will be aware, we have collaborated in many ways over a relatively long period and have co-authored two other books on reliability evaluation. Both of these previous books were structured as teaching texts. This present book is not a discourse on "how to do reliability evaluation" but a discussion on "why it should be done and what can be done and achieved" and as such does not replace or conflict with the previous books. The three books are complementary and each enhances the others. The material contained in this book is not specifically original since it is based on information which we have published in other forms either jointly or as co­ authors with various other people, particularly our many research students. We sincerely acknowledge the important contributions made by all these students and colleagues. There are too many to mention individually in this preface but their names appear frequently in the references at the end of each chapter.

The purpose of this book is to analyze, with actual examples, different techniques that have been developed to tackle the complex task of making an Environmental Impact Assessment (EIA) of a project. A project may influence the lives of many people, can change the physical environment temporarily or forever, and creates benefits or losses, not only for the people who promoted it, but also for those not related whatsoever with the project. Thus, its assessment is not only a commercial evaluation of gains and losses, but it goes far beyond that, for it also has to appraise: Even though, in many cases, the different techniques can be used standalone, this procedure appears to be unsatisfactory, because none of them can give a complete answer to our problem. For that reason this book explains each technique separately, but whenever possible, and through examples, links them in order to obtain the maximum benefit from each one.This book is subtitled A Practical Guide, precisely because it tries to guide the practitioner in this labyrinth of techniques, by suggesting the best tools to use in each case, complementing this with abundant Internet references that provide a fast way to get more information about specific concepts, and facilitating the examination of actual EIA in many different fields. Audience: This book will help the practitioner, the student, and the public in general on how best to understand and evaluate the effects of new projects on our environment. Worksheets to prepare an EIA are included.

Power Quality Enhancement Using Custom Power Devices considers the structure, control and performance of series compensating DVR, the shunt DSTATCOM and the shunt with series UPQC for power quality improvement in electricity distribution.Also addressed are other power electronic devices for improving power quality in Solid State Transfer Switches and Fault Current Limiters. Applications for these technologies as they relate to compensating busses supplied by a weak line and for distributed generation connections in rural networks, are included. In depth treatment of inverters to achieve voltage support, voltage balancing, harmonic suppression and transient suppression in realistic network environments are also covered. New material on the potential for shunt and series compensation which emphasizes the importance of control design has been introduced.

HVDC and FACTS Controllers: Applications of Static Converters in Power Systems focuses on the technical advances and developments that have taken place in the past ten years or so in the fields of High Voltage DC transmission and Flexible AC transmission systems. These advances (in HVDC transmission and FACTS) have added a new dimension to power transmission capabilities. The book covers a wide variety of topics, some of which are listed below: In addition to EHV transmission, HVDC technology has impacted on a number of other areas as well. As an example, a chapter dealing with HVDC Light applications is included providing recent information on both on-shore and off-shore applications of wind farms. HVDC and FACTS Controllers: Applications of Static Converters in Power Systems is meant for senior undergraduate, graduate students and professional power systems engineers. Mathematical treatment of the subject has been kept to a minimum and emphasis has been placed on principles and practical applications. Applications from major manufacturers are included to provide useable information for the practicing power systems engineer.

HVDC and FACTS Controllers: Applications of Static Converters in Power Systems focuses on the technical advances and developments that have taken place in the past ten years or so in the fields of High Voltage DC transmission and Flexible AC transmission systems. These advances (in HVDC transmission and FACTS) have added a new dimension to power transmission capabilities. The book covers a wide variety of topics, some of which are listed below: In addition to EHV transmission, HVDC technology has impacted on a number of other areas as well. As an example, a chapter dealing with HVDC Light applications is included providing recent information on both on-shore and off-shore applications of wind farms. HVDC and FACTS Controllers: Applications of Static Converters in Power Systems is meant for senior undergraduate, graduate students and professional power systems engineers. Mathematical treatment of the subject has been kept to a minimum and emphasis has been placed on principles and practical applications. Applications from major manufacturers are included to provide useable information for the practicing power systems engineer.