Electric Power Systems E-Book

Alexandra von Meier

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1330

Veröffentlichungsjahr: 2024

Beschreibung

Discover the technology for producing and delivering electricity in this easily accessible introduction to power systems

Electric Power Systems underlie virtually every aspect of modern life. In the face of an unprecedented transition from fossil fuels to clean energy, it has never been more essential for engineers and other professionals from diverse disciplines to understand the electric grid and help chart its future. Since its original publication, Electric Power Systems has served as a uniquely accessible and qualitative introduction to the subject, offering a foundational overview with an emphasis on key concepts and building physical intuition. Now revised and updated to bring even greater rigor and incorporate the latest technologies, it remains an indispensable introduction to this vital subject.

Readers of the revised and expanded second edition of Electric Power Systems will also find:

• End-of-chapter problems to facilitate and reinforce learning
• New discussions of subjects including load frequency control, protection, voltage stability, and many others
• More quantitative treatment of topics such as voltage regulation, power flow analysis, generator and transformer modeling with numerical examples
• Entirely new chapters on generation and storage resources, power electronics, and the analysis of transmission lines

Electric Power Systems is an ideal textbook for graduate and advanced undergraduate students in engineering, as well as for a broad range of professionals, such as computer and data scientists, solar and wind energy manufacturers and installers, energy storage providers, economists, policy makers, legal and regulatory staff, and advocacy organizations.

Leseprobe

IEEE Press445 Hoes LanePiscataway, NJ 08854

IEEE Press Editorial BoardSarah Spurgeon, Editor-in-Chief

Moeness Amin

Jón Atli Benediktsson

Adam Drobot

James Duncan

Ekram Hossain

Brian Johnson

Hai Li

James Lyke

Joydeep Mitra

Desineni Subbaram Naidu

Tony Q. S. Quek

Behzad Razavi

Thomas Robertazzi

Diomidis Spinellis

Electric Power Systems

A Conceptual Introduction

Second Edition

Alexandra von Meier

Copyright © 2024 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey.Published simultaneously in Canada.

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Library of Congress Cataloging-in-Publication Data

Names: Meier, Alexandra von, author.

Title: Electric power systems : a conceptual introduction / Alexandra von

  Meier.

Description: Second edition. | Hoboken, New Jersey : John Wiley & Sons, Inc.,

  [2024] | Includes index.

Identifiers: LCCN 2024011469 (print) | LCCN 2024011470 (ebook) | ISBN

  9781394241002 (Hardback) | ISBN 9781394241026 (adobe pdf) | ISBN

  9781394241019 (epub)

Subjects: LCSH: Electric power systems.

Classification: LCC TK1005 .M37 2024 (print) | LCC TK1005 (ebook) | DDC

  621.31–dc23/eng/20240402

LC record available at https://lccn.loc.gov/2024011469

LC ebook record available at https://lccn.loc.gov/2024011470

Cover Design: WileyCover Image: Courtesy of the Author

To my late grandfatherKarl Wilhelm Claubergwho introduced me toThe Joy of Explaining Things

List of Figures

Figure 1.1

Electric field of (a) a single charge and (b) two opposite charge.

Figure 1.2

Magnetic field around a current-carrying wire.

Figure 1.3

The Lorentz force acting on charges moving through a magnetic field.

Figure 1.4

An electromagnetic wave.

Figure 2.1

Resistors in series.

Figure 2.2

Resistors in parallel.

Figure 2.3

Network reduction.

Figure 2.4

Kirchhoff’s voltage law.

Figure 2.5

Kirchhoff’s current law.

Figure 2.6

Superposition. (a) Full circuit. (b) Circuit with only the voltage source. (c) Circuit with only the current source.

Figure 2.7

A one-port representing a relationship between voltage and current , governed by whatever is inside the box.

Figure 2.8

A simple, linear battery operating characteristic (a) and Thévenin equivalent circuit (b).

Figure 2.9

(a) The current–voltage operating characteristic or – curve for an ideal photovoltaic cell, and (b) the circuit model that reproduces this behavior using an ideal current source and diode. A more realistic model would include a series and parallel resistance for losses within the cell.

Figure 2.10

Operating characteristic for a linear one-port with Thévenin and Norton equivalents.

Figure 2.11

Sample linear circuit.

Figure 2.12

Thévenin (a) and Norton (b) equivalents of the circuit in Figure 2.11.

Figure 2.13

A magnetic circuit.

Figure 2.14

Network of resistors.

Figure 3.1

A sine function plotted against time or, equivalently, angle .

Figure 3.2

Sinusoidal alternating current with phase shift.

Figure 3.3

Derivation of the rms value.

Figure 3.4

A basic inductor, or solenoid.

Figure 3.5

Current lagging voltage by 90. These functions could be written as and . Note that the relative amplitudes are unimportant, because they are measured in different units.

Figure 3.6

A basic capacitor, with arrows indicating the electric field.

Figure 3.7

Current leading voltage by .

Figure 3.8

The number in the complex plane. In polar notation,

Figure 3.9

The impedance

Z

represented in the complex plane, with resistance

R

in the real direction and reactance in the imaginary direction. Here the reactance is inductive and points upward; a capacitive reactance would point downward in the direction of . The length of the hypotenuse is .

Figure 3.10

Simple series circuit to illustrate the addition of impedances.

Figure 3.11

Parallel circuit to illustrate the addition of admittances, using the same elements as in Figure 3.10.

Figure 3.12

Power as the product of voltage and current, with current lagging behind voltage by a phase angle difference .

Figure 3.13

Complex power

S

with real power in the real and reactive power in the imaginary direction. The positive angle in the figure indicates an inductive load, with current lagging voltage.

Figure 3.14

A phasor in the complex plane.

Figure 3.15

Phasors in relation to each other.

Figure 3.16

Complex exponentials. An increasing imaginary exponent corresponds to counterclockwise rotation in the complex plane.

Figure 3.17

Series circuit to illustrate KVL for the complex case.

Figure 3.18

Phasor addition of voltages associated with Figure 3.17 in the complex plane. Note that the length of the current phasor is arbitrary since it is in different units; it is shown for angle reference only.

Figure 3.19

Parallel circuit to illustrate KCL for the complex case.

Figure 3.20

Phasor addition in the complex plane of currents associated with Figure 3.19.

Figure 3.21

Two voltage sources that could be acting as generators or loads.

Figure 4.1

Three balanced single-phase a.c. currents.

Figure 4.2

Three phases with and without neutral return; (a) three phases with common return; (b) three phases with neutral removed.

Figure 4.3

(a) Delta and (b) wye connections.

Figure 4.4

Phase-to-phase (line-to-line) voltage, seen in the time domain as the difference between a pair of phase-to-neutral (line-to-neutral) voltages.

Figure 4.5

Line-to-line and line-to-neutral voltages represented in the phasor domain. The two different graphic arrangements are functionally identical: although the right diagram appears to “connect” voltages of the same value to support intuition, a phasor diagram is not a circuit diagram.

Figure 4.6

Currents in a wye connection.

Figure 4.7

Currents in a delta connection.

Figure 4.8

Current phasors showing the relationships between line currents (, and ) and the currents through a delta-connected load (, and ).

Figure 4.9

Positive-, negative-, and zero-sequence components. Each trio includes three phasors of equal magnitude, imagined as rotating counterclockwise.

Figure 4.10

Vector addition of the symmetrical components in Figure 4.10, corresponding to Eq. 4.6.

Figure 4.11

Various international practices for delta connections.

Figure 5.1

ITIC curve.

Figure 5.2

Transient voltage waveform disturbance, as seen with a PQube power quality recorder.

Figure 5.3

Simulated current drawn by a highly nonlinear load and its effect on voltage due to source impedance, visualized in the Power Quality Teaching Toy.

Figure 5.4

The third harmonic of all three phases coincides.

Figure 6.1

Standard U.S. electrical outlet or wall socket.

Figure 6.2

Transformer taps and multiphase service.

Figure 6.3

Example of a load profile from California ISO. Source: Adapted from California Independent System Operator.

Figure 6.4

Example of a load duration curve.

Figure 6.5

Load profile on a mild, sunny day.

Figure 7.1

Historical growth of generation unit size and transmission voltage.

Figure 7.2

Regions and interconnections of the U.S. electric grid. Source: U.S. Energy Information Agency, 2016/Public Domain.

Figure 7.3

Real-time frequency in the major synchronous interconnections in North America, as seen on FNET (University of Tennessee, Knoxville and Oak Ridge National Laboratory). The variations indicated on the color legend represent fractions of a hertz above or below the nominal 60.00 Hz. Source: The University of Tennessee Knoxville/https://fnetpublic.utk.edu/frequencymap.

Figure 7.4

One-line diagram showing basic power system structure.

Figure 7.5

North American (a) and European (b) distribution systems.

Figure 7.6

Distribution substation layout.

Figure 7.7

Distribution substation with transformers of different vintage, supplied from 60 kV subtransmission (left). Also visible are voltage regulators (back right), small service transformers (far right), and simple mechanical switches (operated with a hookstick).

Figure 7.8

Radial distribution system.

Figure 7.9

Loop system.

Figure 7.10

Networked topology.

Figure 7.11

Loop flow.

Figure 7.12

Sample transmission-line dimensions.

Figure 7.13

Transposition tower for a 380-kV line in Germany, carrying two three-phase circuits. For example, the middle phase at the front left is moved to the top position on the right. Also discernible on the photo are bundled conductors with two subconductors per bundle, and corona rings at the ends of the insulators.

Figure 7.14

The 500 kV Pacific DC Intertie (PDCI) and a three-phase 230 kV a.c. transmission line near Bishop, California.

Figure 7.15

Real power flow as a function of voltage phase angle difference.

Figure 7.16

Thermal and stability limits for a hypothetical line.

Figure 7.17

Voltage drop along a distribution feeder.

Figure 7.18

Effect of a line voltage regulator on the voltage profile of a radial distribution feeder.

Figure 7.19

Effect of a capacitor on the voltage profile of a radial distribution feeder.

Figure 7.20

Sample time–current characteristic of a relay.

Figure 7.21

Recloser operation with transient fault.

Figure 7.22

Recloser operation with a permanent fault. There could be several additional reclosing attempts (fast or slow) before locking out.

Figure 7.23

Example of protection zones with oil circuit breakers (OCB) and recloser (REC).

Figure 7.24

Protection zones—fuses.

Figure 7.25

Protection zones—reclosers.

Figure 7.26

Protection zones—relay.

Figure 7.27

Sample coordination with time–current curves for a fuse and a recloser.

Figure 7.28

– circuit of fault loop shorted at .

Figure 7.29

The role of fault inception: current increases during the entire time that voltage remains positive on the first cycle. (a) Fault incepts at when . (b) Fault incepts at when (worst case).

Figure 7.30

Symmetrical (a) and asymmetrical (b) current with a decaying d.c. component due to the timing of the fault’s inception.

Figure 8.1

Transformer concept. A realistic transformer performs better if the core forms a closed loop, as shown in Figure 2.13.

Figure 8.2

Transformer at a distribution substation.

Figure 8.3

Three-phase transformer connections.

Figure 8.4

Autotransformer.

Figure 8.5

Magnetization versus magnetic field strength for a theoretical transformer core, illustrating hysteresis. The intercepts are for saturation remanence and for coercivity.

Figure 8.6

Equivalent circuit model for a realistic transformer.

Figure 8.7

Transformer example with series impedance only, neglecting shunt admittance.

Figure 8.8

Transformer example with series elements only (neglecting shunt admittance).

Figure 8.9

Vector addition for voltage drop across a series impedance, in the case where load current is aligned with voltage (p.f. ).

Figure 8.10

Projecting voltage drop onto the real axis to approximate as in Eq. (8.6), for lagging and leading current. Voltage drop is exaggerated for clarity.

Figure 8.11

Adding series impedances in per-unit across multiple zones with different base voltages.

Figure 9.1

The magnetic field around a single current-carrying wire.

Figure 9.2

Integrating over the magnetic flux density around a single current-carrying wire.

Figure 9.3

Accounting for the fraction of enclosed current at inside the conductor, assuming uniform current density.

Figure 9.4

When the return conductor is inside the path integral, the enclosed current and therefore the magnetic flux is zero. The same applies to a three-phase circuit.

Figure 9.5

Three-phase conductors in an equilateral arrangement, with equal spacing between each.

Figure 9.6

Sample three-phase transmission line geometry.

Figure 9.7

Visualizing capacitance between a pair of conductors.

Figure 9.8

Series addition of capacitance.

Figure 9.9

Short transmission line model, which accounts for only the series impedance . This model requires .

Figure 9.10

Voltage drop across a short transmission line for a load of lagging, unity, and leading power factor. Note that the magnitude of on the phasor diagram is arbitrary, but the products and have dimensions of voltage and are therefore to scale. (a) Load p.f. = 70% lag, (b) Load p.f. = 100%, and (c) Load p.f. = 70% lead.

Figure 9.11

Equivalent -circuit for a medium-length transmission line.

Figure 9.12

Derivation of the interdependence of voltage and current as a function of distance along a transmission line, with distributed line parameters.

Figure 9.13

(a) Adjacent conductor strands. (b) Conductor strands separated by a distance

d

within a bundled conductor.

Figure 9.14

Cross section of a three-phase transmission line with bundled conductors.

Figure 10.1

The notional “simple generator.”

Figure 10.2

Changing flux and

emf

versus time.

Figure 10.3

Simple generator with armature reaction.

Figure 10.4

Schematic of a direct-current motor.

Figure 10.5

Paperclip motor.

Figure 10.6

Cylindrical rotor and its magnetic field.

Figure 10.7

Schematic arrangement of three-phase stator winding.

Figure 10.8

Contribution to armature reaction from one phase.

Figure 10.9

Three-phase armature reaction.

Figure 10.10

Magnetic field of a four-pole rotor.

Figure 10.11

Controlling generator output with the governor valve.

Figure 10.12

Flux, armature voltage, and current versus time; unity power factor.

Figure 10.13

Flux, armature voltage, and current versus time; lagging power factor.

Figure 10.14

Flux, armature voltage, and current versus time; leading power factor.

Figure 10.15

Rotor and stator field, unity power factor.

Figure 10.16

Rotor and stator field, lagging power factor.

Figure 10.17

Rotor and stator field, leading power factor.

Figure 10.18

Decomposition of the stator field.

Figure 10.19

The power angle.

Figure 10.20

“Difference voltage” due to phase angle shift, resulting in a circulating current in phase with voltage that affects real power exchange.

Figure 10.21

Circulating current with Unit 1 providing more reactive power.

Figure 10.22

Sample allocation of reactive power among generators.

Figure 10.23

Reactive capability curve.

Figure 10.24

Torque versus slip for an induction machine.

Figure 10.25

Illustration from Nikola Tesla’s a.c. motor patent.

Figure 10.26

Simplified single-phase round rotor machine, with notional magnetic flux lines from the armature windings.

Figure 10.27

Simple equivalent generator circuit model.

Figure 10.28

Phasor diagram for the equivalent circuit in Figure 10.27.

Figure 11.1

James Watt governor. Source: Routledge/Wikipedia/CC BY 4.0.

Figure 11.2

Droop curve showing the relationship between and .

Figure 11.3

Droop control with a single generator.

Figure 11.4

Droop control with two generators. Points a are the initial state, b after primary response, and c the final state after secondary response, in which only Unit 2 participates.

Figure 11.5

Visualizing tie line flow between neighboring control areas.

Figure 11.6

Three areas sharing frequency regulation resources (initial operating condition for text example).

Figure 11.7

Grid frequency on a typical day in California, measured at a wall outlet with a micro-phasor measurement unit (PMU) and visualized in the Berkeley Tree Database (BTrDB).

Figure 11.8

Generation scheduling with the load duration curve.

Figure 11.9

Droop curves for two generators.

Figure 11.10

Frequency volatility (a) and nadir for loss-of-generation events (b) in West Berlin, before and after interconnection with Western Europe.

Figure 12.1

One-line diagram for a fictitious power system.

Figure 12.2

Current is found by adding currents , superimposing the two partial circuits on the center branch. This works because all circuit elements have linear characterizations.

Figure 12.3

In a nonlinear system, we cannot directly solve for or .

Figure 12.4

Six-bus power flow example.

Figure 12.5

Six-bus power flow example with losses.

Figure 12.6

Modified six-bus power flow example.

Figure 12.7

Common rotating line shaft in a yarn spinning factory (Leipzig, ca. 1925) as a mechanical analog to a.c. power transfer.

Figure 12.8

Simple network to illustrate obtaining branch admittances.

Figure 12.9

Simple two-bus network to illustrate allocation of transmission line capacitance.

Figure 12.10

Newton’s method.

Figure 12.11

Iterative process of approximating

Figure 12.12

Two-bus power flow example visualized in

PowerWorld

. Source: U.S.-Canada Power System Outage Task Force, 2004/United States Department of Energy/Public Domain.

Figure 12.13

Two-bus power flow example solved in

PowerWorld

TM

.

Figure 12.14

The unrealistic low-voltage solution to the two-bus power flow example.

Figure 12.15

Convergence regions for the two-bus power flow example.

Figure 12.16

Three-bus network.

Figure 12.17

Radial distribution branch for the derivation of LinDistFlow equations.

Figure 12.18

Qualitative association of voltage drop and angle difference with the direction of real and reactive power flow, based on Eqs. (12.5) and (12.8). and indicate positive power flowing from Node 1 to 2, in the sense of in Figure 12.17. indicates that , and that . (a) When , the sign of is aligned with real and with reactive power flow. (b) When , the relationship rotates by 45.

Figure 12.19

Three-bus example for Problems 12.4 and 12.5.

Figure 13.1

Toy example illustrating –1 security.

Figure 13.2

Stable and unstable equilibria: (a) bowl and marble in stable equilibrium; (b) ruler in unstable equilibrium.

Figure 13.3

Power transmitted versus power angle.

Figure 13.4

(a) Deep and (b) shallow equilibria.

Figure 13.5

Power generated as a function of power angle.

Figure 13.6

Damped harmonic oscillation in , as modeled and measured between two locations in Texas, illustrating generator swing and ringdown after the sudden loss of another generator.

Figure 13.7

Restoring power and “potential energy” , where K.E. = kinetic energy; P.E. = potential energy.

Figure 13.8

Equal area criterion.

Figure 13.9

Real power transfer as a function of voltage phase angle difference across an inductive transmission line.

Figure 13.10

Family of – curves.

Figure 13.11

– curve showing bus voltage magnitude versus reactive power injection (negative reactive load) for a simple radial system.

Figure 13.12

Family of – curves for different transmission path impedances, illustrating the problem of voltage security.

Figure 14.1

Mercury arc valve, configured as (a) a half-wave (three anodes) and (b) full-wave (six anodes) rectifier.

Figure 14.2

Basic schematic of a vacuum triode, with labels for cathode, plate (anode), and grid.

Figure 14.3

p–n Junction and electric field.

Figure 14.4

Inverter waveforms.

Figure 14.5

Pulse-width modulation with 8 cycles (a) and 16 cycles (b). Horizontal gray lines represent the average value of each pulse.

Figure 14.6

Full-bridge inverter circuit.

Figure 14.7

PWM signal, simplified for clarity. Actual carrier wave frequency would be much greater.

Figure 14.8

Sample volt-VAR droop curve. The per-unit (p.u.) scales indicate a decimal fraction of nominal voltage and maximum available power, respectively. The corner points that define the curve are specified based on local utility requirements.

Figure 14.9

Sample volt-watt droop curve. The corner points that define the curve are specified based on local utility requirements.

Figure 15.1

Conceptual illustration for a fossil-fuel power plant.

Figure 15.2

Microgrid concept, with generation (circles), storage (triangle), and loads (rectangles) at various scales. Dashed lines indicate optional connections.

Figure 16.1

Time scales in electric grid operation.

Figure 16.2

Making a voltage measurement on a parallel branch.

Figure 16.3

Potential and current transformers.

Figure 16.4

Voltage divider.

Figure 16.5

Oscillations in local a.c. frequency due to generators swinging against each other, rendered observable with early PMUs.

Figure 16.6

Recorded waveforms during a transmission fault. Source: NERC (2017)/with permission of North American Electric Reliability Corporation.

Figure 16.7

California Independent System Operator (CAISO) control room. Source: California Independent System Operator.

Preface

This book is a labor of love. It is intended to bridge the gap between standard engineering texts and more popularly accessible descriptions of electric power technology. I discovered this gap as a graduate student struggling to understand power systems, which had always fascinated me, but which I now needed to understand properly in the context of my passion, implementing solar energy. Although I had studied physics as an undergraduate, I found the subject of power systems difficult and intimidating.

The available literature seemed to fall into two categories: easy-to-read, qualitative descriptions of the electric grid for the layperson on the one hand, and highly technical books and papers on the other, written for professionals and electrical engineering majors. The second category had the information I needed, but guarded by a layer of impenetrable phasor diagrams and other symbolism that clearly required some sort of initiation.

I was very fortunate to study with renowned experts at the University of California, Berkeley, including Leon Chua and Felix Wu, who were also generous and gifted teachers and brought me up to speed in deciphering the academic and engineering literature. The formative learning experience was a research project beginning in 1989 at several large nuclear and fossil-fueled steam generation plants, where our team interviewed the staff as part of a study on High-Reliability Organizations. My own subsequent research on power distribution took me into the field with five U.S. utilities and one in Germany. Aside from the many intriguing things we learned about the operating culture in these settings, I discovered how clearly the power plant staff could often explain technical concepts about their working systems. Their language was characteristically plain and direct and was always guided by practical considerations, such as, What does this dial tell you? What happens when you push that button?

In hindsight, the defining moment for inspiring this book occurred in the Pittsburg control room when I revealed my ignorance about reactive power (ironically, having just boasted about my physics degree, to the operators’ benign amusement). They generously supplied me with a copy of the plant operating manual, which turned out to contain the single most lucid and comprehensible explanation of electric generators, including reactive power, I had seen. That manual proved to me that one can write about electric power systems in a way that is accessible to audiences who have not undergone the initiation rites of an academic engineering program, but who nevertheless want to get the real story. I imagined there might be other people much like myself—outside the engineering profession or the power industry but vitally concerned with it—who could benefit from such a practical approach.

After finishing my dissertation in 1995, I decided to give it a try. My goal was to write the book that I would have wanted to read as a student. The guiding principle was to assume a minimum of prior knowledge on the part of the readers while trying to relate as much as possible to their direct experience and intuition. In essence, the book should explain how the electric grid works and what its relevant technical constraints are. It should convey a sense of the complexity of the system as a whole and point to the tools used by power engineers to navigate that complexity. Though it could not be expected to offer a full professional training in the use of these tools, it should prepare readers for the more specialized literature or advanced coursework. Enough historical context should be provided to view technological innovation both from the standpoint of modern opportunities and the challenges presented by the legacy infrastructure.

From the start, I envisioned two main audiences. The first consists of students and researchers who are learning about electricity and power engineering in an academic setting, and who feel that their understanding would be enhanced by a qualitative, conceptual emphasis to complement the quantitative methods stressed in technical courses. This audience might include students of diverse backgrounds or differing levels of preparation, perhaps transferring into an engineering program from other disciplines. Such students often need to solidify their understanding of basic information that is presumed to be second nature to advanced undergraduates in technical fields. As a supplement to standard engineering texts, the first edition aimed to provide a clear and accessible review of units, definitions, and fundamental physical principles; to explain in words the ideas shown by equations; to contextualize information, highlighting connections among different topics and pointing out their relevance; and to offer a glimpse into the practical world of the electric power industry.

The second major audience consists of professionals working in and around the power industry whose educational background may not be in electrical engineering, but who wish to become more familiar with some of the technical details and the theoretical underpinnings of the system they deal with. This group might include analysts, administrators, and managers coming from fields of business, economics, law, or public policy, as well as individuals with technical or multidisciplinary training in areas other than power engineering.

The project was more ambitious than I had imagined, and the first edition took a decade to write—but it also met with more success than I had dared to hope. After 13 years as a professor of Energy Management & Design at Sonoma State University, I returned to Berkeley in 2012 to teach a power systems course in the Department of Electrical Engineering and Computer Science and to direct electric grid research at the California Institute for Energy and Environment. My group’s research primarily focused on the application of novel sensing, analytics, and control strategies to facilitate the grid integration of renewable resources. This work gave me the opportunity to connect with and learn from many experts, especially through the North American Synchrophasor Initiative (NASPI). It also reinforced the sense that a growing audience of scholars and practitioners from diverse fields could use help understanding how the electric grid works.

The two-semester course Introduction to Electric Power Systems I developed and taught for 10 years gives an overview of the legacy electric grid and highlights opportunities and challenges associated with incorporating new technologies. The course has served engineering majors as well as students at both the undergraduate and graduate level from other departments with an interest in the electric grid and with enough preparation to handle the quantitative assignments. I used the first edition of this book for my class, but had to supplement it with other resources to cover some of the more technical aspects. Over time, my accumulated lecture notes evolved into this substantially expanded second edition, which aims to serve as a reasonably complete stand-alone text for introductory engineering courses like mine.

To this end, some chapters were amended to cover more technical points and problem-solving tools, some material was reorganized, and seven new chapters were added. Along with more formal treatment and quantitative examples for many topics, new material in this second edition includes Thévenin and Norton equivalents, symmetrical components, ZIP load models, transmission line analysis, transformer and generator modeling, load frequency control, power transfer limits, power electronics, measurement and data, and a summary chapter on generation and storage resources. Finally, it includes some end-of-chapter problems, with solutions made available separately through the publisher’s website.

While meeting the needs of a rigorous engineering text, this second edition should not sacrifice accessibility for general audiences. It aspires to satisfy readers who think in mathematical terms, and those who don’t. As a rule, conceptual explanations precede mathematical statements, and the more technical portions can be skipped without leaving the reader disoriented. Sections are extensively cross-referenced and intended to be modular. The idea is that the reader can open up the book to any page that piques their curiosity or answers a nagging question and be assisted in locating background information and relevant context elsewhere in the book. There are many plausible ways to organize the material—or likely some subset of it—for a course. Chapters need not be read or covered in sequence. Instructors should be able to select and tailor material to their purposes.

One major change in recent years is the availability of technical content on the Internet, including Wikipedia and YouTube tutorials. Especially for animated visualizations (say, rotating machines!), some of these resources can be immensely valuable. But aside from reliable quality control, what the Internet does not provide is coherent guidance and context. For autodidactic readers, this book aims to serve as a foundation and structure that will support them in the critical consumption and interpretation of other educational materials about electricity-related topics.

This is a great time for many more students, whether inside or outside traditional academic settings, to develop a passion for understanding electric power systems. The electric grid is central to our society, our economy, and our efforts to address global climate change. While being host to a shifting base of energy resources, including inverter-based generation, the infrastructure itself is in the process of being modernized with digital technology. Nobody yet can answer the question, “What does the grid of the future look like?” We urgently need diverse talents and skills applied to this vital problem area. My hope is that this book can make a helpful contribution.

Bishop, CAFebruary 2024                      

Alexandra von Meier

Acknowledgments

Many individuals and organizations have made the writing of this text possible. I will always be deeply grateful to my teachers, most especially Gene Rochlin and Felix Wu, for their mentorship. I am also indebted to the many industry professionals who took the time to show me around power systems in the field and teach me about their work.

The writing of the first edition was supported both directly and indirectly by a University of California President’s Postdoctoral Fellowship, the University of California Energy Institute (UCEI), the California Energy Commission, and the California Institute for Energy and Environment (CIEE). Carl Blumstein, Ron Hofmann, and Laurie ten Hope made possible a series of tutorials that developed early material for the book.

Cary Berkley, Thomas Harris, Darcy McCormick, and Steve Shoptaugh helped with graphics and assembling the first edition. Special thanks go to Andrew Busby and Wei Lao for their tireless work in wrangling the second edition manuscript and Michael Sankur for creating numerous, greatly improved new figures.

The second edition benefited immeasurably from the thoughtful and creative contributions of my teaching assistants for EE 137AB at UC Berkeley: Dan Arnold, Mohini Bariya, Kyle Brady, Samantha Coday, Roel Dobbe, Laurel Dunn, Ioannis Konstantakopoulos, Veda Krishnan, Jonathan Lee, Keith Moffat, Aminy Ostfeld, Michael Sankur, Samuel Smith, Jaimie Swartz, Michaelangelo Tabone, Insoon Yang, and Eric Yehl. I also learned from every student who asked a question in class or office hours that made me stop and think.

I am immensely grateful to my colleagues and friends who read, discussed, helped improve, and generously contributed to the manuscript over the years. They include Raquel Blanco, Carl Blumstein, Duncan Callaway, Joe Eto, Alex Farrell, Hannah Friedman, John Galloway, Mack Grady, Chris Greacen, Sean Greenwalt, Dianne Hawk, Nicole Hopper, Merrill Jones, Jonathan Lee, Chris Marnay, Andrew McAllister, Alex McEachern, Keith Moffat, Tom Overbye, Liz Ratnam, Michael Sankur, Steve Shoptaugh, Leigh Tesfatsion, Jim Williams, and all the readers who took the time to send feedback. Finally, I thank my husband Mike Kearney for his loving support.

Of course, I am solely responsible for any errors. I imagine this text will remain a work in progress, and suggestions for improving its accuracy and clarity will be warmly welcomed.

About the Companion Website

This book is accompanied by a companion website:

www.wiley.com/go/vonmeier/electricpowersystems2

This website includes:

Solution Manual

PowerPoint slides

1Physics of Electricity

1.1 Basic Quantities

This chapter describes the quantities that are essential to our understanding of electricity: charge, voltage, current, resistance, and electric and magnetic fields. Most students of science and engineering find it very hard to gain an intuitive appreciation of these quantities, since they are not part of the way we normally see and make sense of the world around us. Electrical phenomena have a certain mystique that derives from the difficulty of associating them with our direct experience, but also from the knowledge that they embody a potent, fundamental force of nature.

Electric charge is one of the basic dimensions of physical measurement, along with mass, distance, time, and temperature. All units in physics can be expressed as some combination of these terms. Unlike the others, however, charge is more remote from our sensory perception. While we can easily visualize the size of an object, imagine its weight, or anticipate the duration of a process, it is difficult to conceive of “charge” as a tangible phenomenon.

To be sure, electrical processes are vital to our bodies, from cell metabolism to nervous impulses, but we do not usually conceptualize these in terms of electrical quantities or forces. Our most direct and obvious experience of electricity is to receive an electric shock. Here the presence of charge sends such a strong wave of nervous impulses through our body that it produces a distinct and unique sensation. Other firsthand encounters with electricity include hair that defiantly stands on end, a zap from a door knob, and static cling in the laundry. Yet these experiences hardly translate into the context of electric power, where we can witness the effects of electricity, such as a glowing light bulb or a rotating motor, while the essential happenings take place silently and concealed within pieces of metal. For the most part, electricity remains an abstraction to us, and we rely on numerical and geometric representations—aided by liberal analogies from other areas of the physical world—to form concepts and develop an intuition about it.

1.1.1 Charge

It was a major scientific accomplishment to integrate an understanding of electricity with fundamental concepts about the microscopic nature of matter. Observations of static electricity like those mentioned earlier were elegantly explained by Benjamin Franklin in the late 1700s as follows: There exist in nature two types of a property called charge, arbitrarily labeled “positive” and “negative.” Opposite charges attract each other, while like (similar) charges repel. When certain materials rub together, one type of charge can be transferred by friction and “charge up” objects that subsequently repel objects of the same kind (hair), or attract objects of a different kind (polyester and cotton, for instance).

Through a host of ingenious experiments,1 scientists arrived at a model of the atom as being composed of smaller individual particles with opposite charges, held together by their electrical attraction. Specifically, the nucleus of an atom, which constitutes the vast majority of its mass, contains protons with a positive charge, and is enshrouded by electrons with a negative charge. The nucleus also contains neutrons, which resemble protons, except they have no charge. The electric attraction between protons and electrons just balances the electrons’ natural tendency to escape, which results from both their rapid movement, or kinetic energy, and their mutual electric repulsion. (The repulsion among protons in the nucleus is overcome by another type of force called the