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ISBN: 978-1-119-37614-9

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CONTENTS

Preface

Acknowledgments

Foreword

Chapter 1 Introduction

1.1 Introduction
Bibliography

Chapter 2 Electric Network Analysis in Energy Processing and Smart Grid

2.1 Introduction
2.2 Complex Power Concepts
2.3 Review of AC-Circuit Analysis Using Phasor Diagrams
2.4 Polyphase Systems
2.5 Three-Phase Impedence Loads
2.6 Transformation of Y to Delta and Delta to Y Networks
2.7 Summary of Phase and Line Voltages/Currents for Balanced Three-Phase Systems
2.8 Per-Unit Systems
2.9 Chapter Summary
Exercises
Bibliography

Chapter 3 Magnetic Systems for Energy Processing

3.1 Introduction
3.2 Magnetic Fields
3.3 Equivalent Magnetic and Electric Circuits
3.4 Overview of Magnetic Materials
3.5 Hysteresis Loops and Hysteresis Losses in Ferromagnetic Materials
3.6 Definitions
3.7 Magnetic Circuit Losses
3.8 Producing Magnetic Flux in Air Gap
3.9 Rectangular-Shaped Magnetic Circuits
3.10 Chapter Summary
Exercises
Bibliography

Chapter 4 Transformers

4.1 Introduction
4.2 First Two Maxwell's Laws
4.3 Transformers
4.4 Ideal Single-Phase Transformer Models
4.5 Modeling a Transformer into Equivalent Circuits
4.6 Transformer Testing
4.7 Transformer Specifications
4.8 Three-Phase Power Transformers
4.9 New Advances in Transformer Technology: Solid-State Transformers — an Introduction
4.10 Chapter Summary
Exercises
Bibliography

Chapter 5 Induction Machines

5.1 Introduction
5.2 Construction and Types of Induction Motors
5.3 Operating Principle
5.4 Basic Induction-Motor Concepts
5.5 Induction-Motor Slip
5.6 Rotor Current and Leakage Reactance
5.7 Rotor Copper Loss
5.8 Developing the Equivalent Circuit of Polyphase, Wound-Rotor Induction Motors
5.9 Computing Corresponding Torque of Induction Motors
5.10 Approximation Model for Induction Machines
5.11 Speed Control of Induction Motors
5.12 Application of Induction Motors
5.13 Induction-Generator Principles
5.14 Chapter Summary
Exercises
Bibliography

Chapter 6 Synchronous Machines

6.1 Introduction
6.2 Synchronous-Generator Construction
6.3 Exciters
6.4 Governors
6.5 Synchronous Generator Operating Principle
6.6 Equivalent Circuit of Synchronous Machines
6.7 Synchronous Generator Equivalent Circuits
6.8 Over Excitation and Under Excitation
6.9 Open-Circuit and Short-Circuit Characteristics
6.10 Performance Characteristics of Synchronous Machines
6.11 Generator Compounding Curve
6.12 Synchronous Generator Operating Alone: Concept of Infinite Bus
6.13 Initial Elementary Facts about Synchronous Machines
6.14 Cylindrical-Rotor Machines for Turbo Generators
6.15 Synchronous Machines with Effects of Saliency: Two-Reactance Theory
6.16 the Salient-Pole Machine
6.17 Synchronous Motors
6.18 Synchronous Machines and System Stability
6.19 Chapter Summary
Exercises
Bibliography

Chapter 7 Dc Machines

7.1 Introduction
7.2 Conductor Moving in A Uniform Magnetic Field
7.3 Current-Carrying Conductor in A Uniform Magnetic Field
7.4 Dc-Machine Construction and Nameplate Parameters
7.5 Dc Machine Pertinent Nameplate Parameters
7.6 Development and Configuration of Equivalent Circuits of Dc Machines
7.7 Classification of Dc Machines
7.8 Voltage Regulation
7.9 Power Computation for Dc Machines
7.10 Power Flow and Efficiency
7.11 Dc Motors
7.12 Computation of Speed of Dc Motors
7.13 Dc-Machine Speed-Control Methods
7.14 Ward Leonard System
7.15 Chapter Summary
Exercises
Bibliography

Chapter 8 Permanent-Magnet Motors

8.1 Introduction
8.2 Permanent-Magnet DC Motors
8.3 Permanent-Magnet Synchronous Motors
8.4 Variants of Permanent-Magnet Synchronous Motors
8.5 Chapter Summary
Bibliography

Chapter 9 Renewable Energy Resources

9.1 Introduction
9.2 Distributed Generation Concepts
9.3 DG Benefits
9.4 Working Definitions and Classifications of Renewable Energy
9.5 Renewable-Energy Penetration
9.6 Maximum Penetration Limits of Renewable-Energy Resources
9.7 Constraints to Implementation of Renewable Energy
Exercises
Bibliography

Chapter 10 Storage Systems in the Smart Grid

10.1 Introduction
10.2 Forms of Energy
10.3 Energy Storage Systems
10.4 Cost Benefits of Storage
10.5 Chapter Summary
Bibliography

Chapter 11 Power Electronics

11.1 Introduction
11.2 Power Systems With Power Electronics Architecture
11.3 Elements of Power Electronics
11.4 Power Semiconductor Devices
11.5 Applications of Power Electronics Devices to Machine Control
11.6 Applications of Power Electronics Devices to Power System Devices
11.7 Applications of Power Electronics to Utility, Aerospace, and Shipping
11.8 Facts
11.9 Chapter Summary
Bibliography

Chapter 12 Converters and Inverters

12.1 Introduction
12.2 Definitions
12.3 DC–DC Converters
12.4 Inverters
12.5 Rectifiers
12.6 Applications
12.7 Chapter Summary
Exercises
Bibliography

Chapter 13 Microgrid Application Design and Technology

13.1 Introduction to Microgrids
13.2 Types of Microgrids
13.3 Microgrid Architecture
13.4 Modeling of a Microgrid
13.5 Chapter Summary
Bibliography

Chapter 14 Microgrid Operational Management

14.1 Perfomance Tools of a Microgrid
14.2 Microgrid Functions
14.3 IEEE Standards for Microgrids
14.4 Microgrid Benefits
14.5 Chapter Summary
Bibliography

Chapter 15 the Smart Grid: an Introduction

15.1 Evolution, Drivers, and the Need for Smart Grid
15.2 Comparison of Smart Grid with the Current Grid System
15.3 Architecture of a Smart Grid
15.4 Design for Smart-Grid Function for Bulk Power Systems
15.5 Smart-Grid Challenges
15.6 Design Structure and Procedure for Smart-Grid Best Practices
15.7 Chapter Summary
Bibliography

Chapter 16 Smart-Grid Layers and Control

16.1 Introduction
16.2 Controls for the Smart Grid
16.3 Layers of Smart Grid Within the Grid
16.4 Command, Control, and Communication Applications in Real Time
16.5 Hardware-in-the-Loop for Energy Processing and the Smart Grid
16.6 Cyber-Physical Systems for Smart Grids
16.7 Chapter Summary
Bibliography

Chapter 17 Energy Processing and Smart-Grid Test Beds

17.1 Introduction
17.2 Study of Available Test Beds for the Smart Grid
17.3 Smart Microgrid Test-Bed Design
17.4 Smart-Grid Test Beds
17.5 Smart-Grid Case Studies
17.6 Simulation Tools, Hardware, and Embedded Systems
17.7 Limitations of Existing Smart-Grid Test Beds
17.8 Chapter Summary
Bibliography

Index

End User License Agreement

List of Illustrations

Chapter 2

Figure 2.1 Simplified single-line diagram schematics of a modern electric power system.
Figure 2.2 Phasor diagram of a purely resistive circuit.
Figure 2.3 Phasor diagram of purely inductive circuit.
Figure 2.4 Phasor diagram of a purely capacitive circuit.
Figure 2.5 AC circuit analysis with phasor diagram.
Figure 2.6 Phasor relationships of power system quantities.
Figure 2.7 Equivalent Y diagram.
Figure 2.8 Phase and line voltage representation.
Figure 2.9 Equivalent Y-connected voltage phasor representation.
Figure 2.10 Mesh or delta connection.
Figure 2.11 Delta-connected three-phase loads.
Figure 2.12 Y-connected load.
Figure 2.13 Star-delta conversion of impedances.
Figure 2.14 Delta-star impedance conversion.
Figure Q3 A Wye-Delta Circuit.
Figure Q4 A Wye-Delta Circuit.

Chapter 3

Figure 3.1 Toroidal coil.
Figure 3.2 Magnetic and electric circuit.
Figure 3.3 BH curve for some ferromagnetic materials.
Figure 3.4 BH curve for iron.
Figure 3.5 A hysteresis loop for a solenoid's ferromagnetic core.
Figure 3.6 Magnetic flux leakage and fringing.
Figure 3.7 Toroid with air gap.
Figure 3.8 Rectangular magnetic circuit.
Figure 3.9 Simple series magnetic circuit and analogous electric circuit.
Figure 3.10 Parallel magnetic circuit.
Figure Q2 Copper Core Magnetic Circuit.
Figure Q3 Magnetic Circuit.

Chapter 4

Figure 4.1 Electric or magnetic fields as catalysts for electro-mechanical energy conversion.
Figure 4.2 Power and distribution transformer. Courtesy of ABB Inc.
Figure 4.3 Distribution transformers. (a) Pole-mounted distribution transformer (b) Ground-mounted distribution transformer. Courtesy of ABB Inc.
Figure 4.4 (a) Physical isolating transformer. (b) Isolating system schematic. Courtesy of EREA Energy Engineering BVBV.
Figure 4.5 (a) Schematic of a potential transformer. (b) Three-phase physical voltage transformer. Courtesy of Flex-Core.
Figure 4.6 (a) Schematic of a current transformer. (b) Solid-core current transformer. Courtesy of Flex-Core.
Figure 4.7 Communication transformer. Courtesy of Hangzhou Smart Technology.
Figure 4.8 Autotransformer and its models. (a) Physical autotransformer (b) Step-down model (c) Step-up model. Courtesy of EREA Energy Engineering BVBV.
Figure 4.9 Ideal transformer model.
Figure 4.10 Approximate equivalent circuit of real transformer (parameters referred to primary side).
Figure 4.11 Final approximate equivalent circuit referred to the primary neglecting shunt branch.
Figure 4.12 Final approximate equivalent circuit referred to the primary neglecting shunt branch and winding resistance.
Figure 4.13 Approximate equivalent circuit of real transformer with parameters referred to the secondary side.
Figure 4.14 Approximate equivalent circuit of real transformer (parameters referred to the secondary side).
Figure 4.15 Final approximate equivalent circuit referred to the secondary, neglecting shunt branch.
Figure 4.16 Final approximate equivalent circuit referred to the primary neglecting shunt branch and winding resistance.
Figure 4.17 Circuit for open-circuit test.
Figure 4.18 The equivalent circuit during open circuit.
Figure 4.19 No-load phasor diagram.
Figure 4.20 Set-up for short-circuit test.
Figure 4.21 Equivalent circuit diagram.
Figure 4.22 Phasor equivalent of the transformer.
Figure 4.23 Typical transformer nameplate showing its parameters.
Figure 4.24 Basic solid-state transformer structure.
Figure 4.25 Different SST configurations.
Figure P1 A potential transformer.
Figure Q9 Equivalent circuit diagram of the transformer.

Chapter 5

Figure 5.1 Induction motor stator.
Figure 5.2 Cage-rotor induction motor.
Figure 5.3 Wound-rotor induction motor.
Figure 5.4 Induction-motor equivalent circuit.
Figure 5.5 The ideal transformer model of an induction motor.
Figure 5.6 Induction-motor stator equivalent circuit-transformer analog model.
Figure 5.7 Rotor equivalent circuit of three-phase induction motor at slip frequency.
Figure 5.8 Equivalent circuits of three-phase polyphase induction motors.
Figure 5.9 Approximate equivalent circuit of three-phase induction motor.
Figure 5.10 Induction generator in self-excited mode.

Chapter 6

Figure 6.1 Synchronous generator rotor types. (a) Cylindrical or round rotor (b) Salient-pole rotor.
Figure 6.2 Cross-section of a synchronous machine.
Figure 6.3 Rotor pole showing damper windings.
Figure 6.4 DC generator excitation system.
Figure 6.5 Mechanical governor system.
Figure 6.6 Synchronous generator operating principle. (a) Rotor-stator arrangement (b) 3-Phase AC induced voltage.
Figure 6.7 Phasor diagram relating flux linkage and voltage.
Figure 6.8 Round rotor synchronous generator phasor diagram.
Figure 6.9 Synchronous generator equivalent circuit and phasor diagram.
Figure 6.10 Per phase equivalent model and phasor diagram.
Figure 6.11 (a) Diagram of Open Circuit Test (b) Open-circuit test characteristics.
Figure 6.12 Short-circuit test: circuit connections for test and short-circuit characteristics.
Figure 6.13 Open-circuit and short-circuit characteristics of a synchronous machine.
Figure 6.14 Steady-state power or torque-angle characteristics of a cylindrical rotor machine.
Figure 6.15 Synchronous machine V-curves.
Figure 6.16 A single machine connected to an infinite bus bar.
Figure 6.17 Synchronous generator armature field current curves.
Figure 6.18 Reactive power capability curves.
Figure 6.19 Power and load angle for saliency.
Figure 6.20 Synchronous generator power-flow diagram.
Figure 6.21 Synchronous motor power flow.
Figure 6.22 Phasor diagrams of a synchronous motor.
Figure Q6 Single line diagram of a Power System.

Chapter 7

Figure 7.1 Conductor moving in a magnetic field.
Figure 7.2 Current-carrying conductor in a magnetic field.
Figure 7.3 Front elevation and schematic diagram of DC machine.
Figure 7.4 DC machine equivalent circuit.
Figure 7.5 DC-machine configurations. (a) Series DC machine (b) Shunt DC machine (c) Compound (short shunt) (d) Compound (long shunt).
Figure 7.6 Separately excited DC machine.
Figure 7.7 Terminal and load characteristics of separately excited generator.
Figure 7.8 Losses and energy flow in DC generators and motors. (a) Energyflow in DC motor (b) Energy flow in DC generators.
Figure 7.9 Configuration types of DC motors. Configuration (a) shunt DC motor (b) Series DC motor (c) Compound motor.
Figure 7.10 Torque/armature-current characteristics.
Figure 7.11 Torque/speed characteristics of a DC-motor configuration.
Figure 7.12 Speed/power characteristics of a DC-motor configuration.
Figure 7.13 Speed–power relationship.
Figure 7.14 Speed-torque characteristics of electric machines.
Figure 7.15 Ward Leonard system control scheme.

Chapter 8

Figure 8.1 Permanent magnet DC motor.
Figure 8.2 Movement of flux in PMDC.
Figure 8.3 Equivalent circuit of a permanent magnet DC motor.
Figure 8.4 Graph of current (I) versus torque (T), and flux speed (ω_m) versus current (I).
Figure 8.5 B–H curve.
Figure 8.6 Rotor configurations for permanent-magnet synchronous motor.
Figure 8.7 Arrangement of permanent magnets in synchronous motors.
Figure 8.8 Cross-section of trapezoidal surface-magnet machine.
Figure 8.9 Recoil line graph.
Figure 8.10 Equivalent magnetic-circuit diagram of a permanent-magnet motor.
Figure 8.11 Norton's theorem current-to-voltage transformation.
Figure 8.12 Equivalent circuit 1 of a permanent-magnet motor.
Figure 8.13 Equivalent circuit 2 of a permanent-magnet motor.
Figure 8.14 Equivalent-circuit model of permanent-magnet motor.
Figure 8.15 Permanent-magnet machine operating points on a B–H curve.
Figure 8.16 Cross-section of trapezoidal surface-magnet machine (two poles) with stator in its star form.
Figure 8.17 Stator-phase voltage and current waves in trapezoidal permanent-magnet machine.
Figure 8.18 Cross-section of synchronous reluctance motor.
Figure 8.19 Torque-angle characteristics of a salient-pole machine.
Figure 8.20 Principle of operation of 30° step variable-reluctance stepping motor.
Figure 8.21 A typical switched reluctance motor.
Figure 8.22 Structure of a switched reluctance motor.

Chapter 9

Figure 9.1 PV systems integration with microgrid.
Figure 9.2 PV-equivalent circuit.
Figure 9.3 Modified equivalent circuit.
Figure 9.4 PV-equivalent circuit for both series and parallel resistances.
Figure 9.5 V-I characteristics: PV connected to resistive load.
Figure 9.6 Basic components of a wind-turbine system.
Figure 9.7 Biomass-gasification process.
Figure 9.8 Diversion type hydropower plant.
Figure 9.9 Schematic diagram of fuel-cell system.
Figure 9.10 Oscillating water-column system.
Figure 9.11 Wave-capture system.
Figure 9.12 Schematic diagram of microturbine.
Figure 9.13 Stirling engine.

Chapter 10

Figure 10.1 Flywheel.
Figure 10.2 Pumped hydro energy storage system.
Figure 10.3 Different kinds of batteries. (a) Dry cell. (b) Automotive battery. (c) Deep-cycle battery. (d) Bank of deep-cycle batteries.
Figure 10.4 Batteries in series and parallel.
Figure 10.5 Battery storage application in a solar PV system.
Figure 10.6 A supercapacitor.
Figure 10.7 Typical equivalent model of an electromechanical double-layer capacitor.
Figure 10.8 Illustration of an SMES system.

Chapter 11

Figure 11.1 Architecture of power system with power electronic devices.
Figure 11.2 Schematic symbol of a diode.
Figure 11.3 (a) Soft reverse-recovery characteristics. (b) Abrupt reverse-recovery characteristics.
Figure 11.4 Typical diode-switching characteristics. (a) Switching circuit with S closed at t = t₀. (b) Diode current.
Figure 11.5 V–I characteristics of a diode. (a) Practical characteristics. (b) Ideal characteristics.
Figure 11.6 Diode waveform illustrations. (a) Positive clipper. (b) Negative clipper.
Figure 11.7 Diode as a rectifier.
Figure 11.8 Resultant output waveform.
Figure 11.9 Clamping configuration.
Figure 11.10 Diode-limiter circuit.
Figure 11.11 npn transistor.
Figure 11.12 pnp transistor.
Figure 11.13 Circuit operation modes of the BJT.
Figure 11.14 CB input characteristics.
Figure 11.15 CB output characteristics.
Figure 11.16 CE input characteristics.
Figure 11.17 CE output characteristics.
Figure 11.18 CB input characteristics.
Figure 11.19 CC output characteristics.
Figure 11.20 Switching characteristics of BJT. (a) Circuit. (b) Switching waveform
Figure 11.21 Circuit symbols of enhancement-type and depletion-type MOSFETs. (a) Enhancement-type MOSFET (b) Depletion-type MOSFET.
Figure 11.22 Transfer characteristics of MOSFETs.
Figure 11.23 Circuit symbol and equivalent circuit for an IGBT.
Figure 11.24 Static characteristics of an IGBT. (a) Output characteristics (b) Transfer characteristics.
Figure 11.25 Switching characteristics of SCR. (a) I–V characteristics and symbolic representation (b) Ideal-switching characteristics.
Figure 11.26 SCR circuit and characteristics. (a) Circuit. (b) v-i characteristics.
Figure 11.27 SCR equivalent circuit.
Figure 11.28 SCR half-wave rectifier and waveform. (a) SCR half-wave rectifier. (b) Waveform and trigger pulse.
Figure 11.29 SCR full-wave rectifier and waveform.
Figure 11.30 SCR full-wave bridge rectifier.
Figure 11.31 Switching characteristics of a TRIAC. (a) I–V characteristics and symbolic representation (b) Ideal-switching characteristics.
Figure 11.32 Step-down chopper with resistive load.
Figure 11.33 Step-down choppers: output voltage and current waveforms.
Figure 11.34 DC Motor Chopper Circuit.
Figure 11.35 Solid-state DC circuit breaker.
Figure 11.36 Solid-state relay.

Chapter 12

Figure 12.1 A DC–DC converter system.
Figure 12.2 Basic DC–DC conversion.
Figure 12.3 Step-down DC–DC converter.
Figure 12.4 Step-up DC–DC converter.
Figure 12.5 Buck–boost converter.
Figure 12.6 Ćuk DC–DC converter.
Figure 12.7 Single-phase half-bridge inverter. (a) Circuit. (b) Waveforms with resistive load. (c) Load current with highly inductive load.
Figure 12.8 Single-phase full-bridge inverter.
Figure 12.9 Three-phase bridge inverter with Y-connected load.
Figure 12.10 Half-wave rectifier.
Figure 12.11 Graetz bridge rectifier: a full-wave rectifier using four diodes.
Figure 12.12 Full-wave rectifier using a center tap transformer and 2 diodes.
Figure 12.13 Three-phase, half-wave rectifier circuit using thyristors as the switching elements, ignoring supply inductance.
Figure 12.14 Three-phase, full-wave rectifier circuit using thyristors as the switching elements, with a center-tapped transformer, ignoring supply inductance.
Figure 12.15 Switchable full-bridge/voltage doubler.
Figure Q12.5.3 Single phase full bridge inverter.
Figure Q12.5.4 Three-phase half-bridge inverter.
Figure Q12.5.5 Single-phase fully-controlled bridge converter.
Figure Q12.5.1 Three-phase half-bridge inverter.
Figure Q12.5.2 Three-phase half-bridge inverter with Purely inductive load.
Figure 12.16 Block diagram of DC–DC converter with a rectifier.
Figure Q12.6.1 Fly back converter.
Figure Q12.6.2 Single phase rectifier.
Figure Q12.6.3 Voltage and Current waveform.
Figure Q12.6.4 Switching scheme for full bridge inverter.

Chapter 13

Figure 13.1 Community microgrid.
Figure 13.2 Architecture of a microgrid.
Figure 13.3 Typical microgrid-connection scheme.

Chapter 14

Figure 14.1 Performance structure of a microgrid EMS.

Chapter 15

Figure 15.1 Architecture of the smart-grid design.
Figure 15.2 Smart grid using advanced optimization and control techniques.
Figure 15.3 Automation functions at transmission level.
Figure 15.4 Automation functions at distribution level.

Chapter 16

Figure 16.1 Hierarchical levels of control in microgrid.
Figure 16.2 Smart-grid layers.
Figure 16.3 Physical layers.
Figure 16.4 Smart meter.
Figure 16.5 Phasor measurement unit.
Figure 16.6 Howard University microgrid test bed with OPAL-RT.
Figure 16.7 Convergence of computation, communication, information, and control.
Figure 16.8 Smart grid with CPS attributes.

PREFACE

THE TRADITIONAL electrical engineering curriculum requires a basic course in electrical machinery, which includes three-phase networks, electromagnetics, transformers, synchronous generators, induction-machine and DC-machine modeling, construction, and performances analysis.

The knowledge of these concepts does not fully prepare students to understand, analyze, and participate in the design, development, and deployment of future grids with features of micro-smart-grid functions. The skills needed include knowledge of classical machine control, real-time measurements, renewable energy resources, storage technology, inverters and converters, and power electronics for processing different energy sources to serve different load models. This book introduces energy-processing concepts and topics needed by students in electrical engineering—and those outside of electrical engineering who will work in future grid development.

The intended audience includes undergraduates and first-year graduate students in a typical engineering program. It is assumed that these students have taken network analysis and electromagnetics courses and hence these topics are only summarized. Full treatment can be found in textbooks on standard machines and electromagnetics.

The idea of this book stems from a research grant from the Department of Energy/National Science Foundation future-grid initiative to the Power System Engineering Research Center/Industry University Collaboration Research Center Research and Workforce Award. As part of this grant, the Howard University team designed research and workforce education materials to contribute to the development of a new curriculum for teaching future energy conversion that will prepare students for handling research and education modules involving future-grid development.

The workforce-education module discussed in this text is a timely assignment since the electrical engineering program at Howard University—like at other universities—is reviewing its curriculum to accommodate new topics in future grid, since there appears to be no single book to present the balance of classical-machine and new trends in energy conversion and processing. This book serves as a reference for students as well as consultants who wish to have a quick overview of machines and energy processing and their relevance to microgrid with smart-grid functions.

Basic materials have been explained with illustrative examples and pictures. In the last few years, the materials in this book have been used to teach required undergraduate courses at Howard University, and some materials were used for teaching first-year graduate students who have a minimum background in energy processing for smart grid. We recommend that any materials too basic for the reader be skipped.

Throughout the book, we tried to minimize details on classical-machine concepts to allow for understanding and working knowledge of processing energy sources in the microgrid/smart-grid environment. We urge the reader to consult advanced books for further reading on these topics.

As noted, we have added some modern topics such as renewable energy, storage technologies, inverters and converters, power electronics, metering, and control for microgrid systems. From our experience thus far, this book will help kindle students’ interest in old-machine analysis and also their pursuit of new topics in design and development of smart-grid and microgrid systems.

The book is organized into nine major sections:

Basic concepts of network analysis applied to power and electromagnetic concepts as relevant to design and understanding of electromechanical systems, which form the backbone of energy processing
Fundamentals of machinery functions, construction, modeling, and performance for transformers, synchronous machines, induction machines, and DC machines
Renewable-energy and storage-technology options for sustainability of energy needs in future grids
Design of inverter and converter and power electronics for energy processing from different sources to serve different loads
Microgrid applications design, technology, and operational management
Review and evaluation of metering communication and control for enabling different functions for operating and managing smart-grid and microgrid systems
Smart-grid design, architecture, security protocols, and real-time measurements
Different test beds and their features with useful energy-processing technology
Exercises for design, testing, and evaluation of energy processing as experimental case studies; this involves a ‘power game’ within an energy-processing platform with OPAL RT in the loop

FOREWORD

INCREASINGLY, ELECTRICITY is being produced from renewable resources—primarily solar and wind—in an effort to mitigate the consequences of global warming resulting from high concentrations of atmospheric carbon dioxide produced by burning fossil fuels. This new direction in energy production and environmental protection requires an extensive re-engineering of the existing electric grid into a computerized future grid—or a smart grid—that accommodates the special characteristics of renewable power-generating technologies. To advance grid modernization, the Power Systems Engineering Research Center (PSERC) has been conducting research with its industry partners on the technical challenges facing the electric power industry.

Keeping up with the education side of its mission, PSERC's faculty has developed software tools, courses, a virtual library, and training materials to ensure the basis of a workforce well versed in implementing the future grid. This book, Energy Processing and Smart Grid, developed as a part of this mission, is divided into three broad sections: energy conversion including renewables, power electronics interfaces, measurements, and controls of the microgrid and smart grid, and test beds for the smart grid.

The author, James A. Momoh, has extensive experience in power system modeling, control, planning, and operations which make him qualified to write a book addressing these topics. This book is a valuable addition to IEEE John Wiley & Sons series which addresses the development of educational tools to meet the needs of the current and future engineers that will be managing these complex cyber-physical systems as well as innovators who will bring future transformations.

The book provides a fundamental understanding of energy processing and technologies needed for building the smart grid. It covers major topics on the fundamentals of smart grid, energy conversion and power electronics, cyber security, real-time measurement, and state estimation techniques. The book is easy to use because it speaks a language that is understandable to both novices and experts. It will serve as a good reference as well as self-study guide for graduate students, research teams, and system operators.

Vijay Vittal

Ira A. Fulton Chair Professor

Director PSERC

School of Electrical, Computer and Energy Engineering

Arizona State University

CHAPTER 1
INTRODUCTION

1.1 INTRODUCTION

The process of electric energy generation, transmission, and distribution is conducted via a large-scale central generation (CG) to meet increasing demand at industrial, commercial, and residential loads. The generation of power through central generation is done via coal-fired, fossil-fuel, hydro, and steam turbines. These resources are converted to electrical energy then processed through different technologies to meet growing load demands. Similarly, the transmission of power from generating units requires high investment, including numerous energy-processing technologies to transfer power to load centers. This is done via transformers and solid-state switching devices at very high voltages. Distribution-system networks are also significant for dispatching power at low voltage via step-down transformers to domestic consumers. Given the different direct current (DC) and alternating current (AC) load models and categories, energy-processing devices such as converters and inverters are needed especially when issues of safety, quality of power, security, and processing are important to meet different loads from various sources.

In recent years, many new distributed generation (DG) sources have been introduced with the aim of reducing losses and increasing reliability, regardless of economy of scale of CG, which can be huge when accounting for cost of transmission and reliability during failure.

DG created from solar, mini-hydro, wind, stirling engines, and fuel cells is of common interest. The debate on how to determine to what extent one should drive CG or DG is a research topic under the future grid initiative. In this paper [1], we were able to show three criteria for selecting which energy sources and processing options should be selected. The criteria included economy of scale, resilience, sustainability, and reliability. Regardless of the choice, appropriate energy processing tools and concepts are a dominant concern moving forward. It is therefore important for a book to be dedicated to addressing appropriate fundamental concepts and technologies for designing, building, and validating the performance of the future grid. That is the goal of this book.

In this book, we propose to provide an integrated foundational knowledge that harnesses the role of energy conversion machines and devices with some new topics for energy generation, transmission, distribution, delivery, and consumption. First, it is relevant to provide the working definition of microgrid.

The microgrid involves a stand-alone or grid-connected system to:

match generation with load
serve as a reserve margin
help stabilize the power system
increase reliability and affordability
reduce the impact of threats on the bulk power system

In contrast, the smart grid is a two-way digital system with active participation of customers within the grid that includes renewable energy resources (RER) with the aim of sustainability and allows reasonable penetration levels and interoperability [2]. It possesses self-healing capabilities; cyber security; and real-time, design-based functions such as reconfiguration, demand-side management (DSM), demand response, and power quality.

We present eight points in this book to support control communications and energy processing for the smart grid. They are the basis of the seventeen chapters, categorized as follows:

A basic review of network (circuit) analysis and electromagnetics is provided. This includes discussion on the fundamental concepts of three-phase analysis of AC sources to different load configurations. The text assumes the sources are AC that can be converted to DC or AC/DC or DC/AC using inverters and converters, as discussed in Chapter 12. A set of hand-calculation exercises is presented although software tools such as NEPLAN [3], Electrical Transient and Analysis Program (ETAP) [4], and Personal Computer Simulation Program with Integrated Circuit Emphasis (PSPICE) [5] can also be used. Balanced or unbalanced conditions can also be analyzed using symmetrical components.
Electromagnetic concepts are introduced by providing the unified theory of Maxwell's equations and their applications for understanding machinery concepts, including transformers, synchronous and induction machines, and DC machines. The unified theories of Faraday, Lenz, and Ampère are given to illustrate the concept of electromagnetic computation. Equivalent analogous forms of magnetic circuits in electric circuits are given for magnetic circuits with rectangular and toroidal shapes with and without air gaps for different ferromagnetic materials.
Fundamental understanding of machines is discussed. This includes the conversion process and the role of Maxwell's equations. The construction and model of the machines using electrical network equivalents are given using short-circuit and open-circuit analyses for determining the equivalent parameters [6]. The power flow in each machine—accounting for conversion, electrical, mechanical, and stray losses—is given. Following this, the text provides a guide for computing efficiency of the power input relative to the output power received. In addition, voltage regulation and control strategies to achieve optimum energy processing are discussed.
Fundamental knowledge of storage and renewable resources is important for development of future grids where sustainability and mobile power are needed. Storage is safe, inexpensive, and the reason for interest in the design of future environmentally friendly grids. The text provides a working model, description, size, and metrics of different resources and storage technologies. Software packages are recommended for studying the impact of RER for reliability and cost–benefit analysis for stand-alone distribution system topologies for the future grid.
Efficient technology to handle processing energy from one state or form to another includes inverters and converters, which provide AC/DC, DC/DC, or DC/AC conversion from a given resource to given loads. To minimize poor power quality, different electronic devices and filters are used. The text provides a fundamental knowledge of power electronics to allow the reader appropriate choices of electronic devices for energy processing.
In designing the operation and management of the smart grid and microgrids, real-time processing of energy and information is essential. We present an overview of real-time data such as voltage, current, power, and frequency, which measure the status of the grid via smart meters and phasor measurement units (PMUs). The formulations and specifications of the devices and their use in communication and control schemes are given. Work in areas of real-time voltage-stability management, power quality, frequency control, voltage/volt-ampere reactive (var), reconfiguration, and several other grid functions are included in the proposed exercises.
We provide a description for understanding the smart grid and microgrid, including functionality, architecture, and the test bed. The chapters integrating the concept of microgrids in this text are an evolving process. Research work and laboratory exercises are important activities for general electrical installations.
Finally, the design of microgrid systems with smart grid functions is described.

Our research involving the design and construction of a microgrid test bed consisting of solar power, super capacitors, batteries, metering devices, converters and inverters, and a real-time simulator is ongoing at Howard University. The introduction of the OPAL-RT real-time digital simulator (RTDS) to the array of research and educational equipment at the Center for Energy Systems and Control (CESaC) at Howard University is allowing us to develop functions such as power quality, voltage stability, voltage/var, DSM, and restoration.

BIBLIOGRAPHY

J. A. Momoh, S. Meliopoulos, and R. Saint, Centralized and Distributed Generated Power System -- A Comparative Approach, PSERC publication, June 2012.
J. Momoh, Smart Grid -- Fundamentals of Design and Analysis, Wiley-IEEE Press, 2012.
https://www.neplan.ch
https://etap.com
www.pspice.com
Mohamed E. El-Hawary, Electrical Power Systems -- Design and Analysis, IEEE Press, 1983.

IEEE Press
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Piscataway, NJ 08854

IEEE Press Editorial Board
Ekram Hossain, Editor in Chief
Giancarlo Fortino	Andreas Molisch	Linda Shafer
David Alan Grier	Saeid Nahavandi	Mohammad Shahidehpour
Donald Heirman	Ray Perez	Sarah Spurgeon
Xiaoou Li	Jeffrey Reed	Ahmet Murat Tekalp

ENERGY PROCESSING
AND SMART GRID

PREFACE

ACKNOWLEDGMENTS

FOREWORD

CHAPTER 1
INTRODUCTION

1.1 INTRODUCTION

BIBLIOGRAPHY