Electrical Power Systems Quality, Second Edition
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Electrical Power Systems Quality, Second Edition


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Electrical Power Systems Quality, Second Edition 
 
 CHAPTER 1: INTRODUCTION 
 What is Power Quality? 
 Power Quality -- Voltage Quality 
 Why Are We Concerned About Power Quality? 
 The Power Quality Evaluation Procedure 
 Who Should Use This Book 
 Overview of the Contents 
 
 CHAPTER 2: TERMS AND DEFINITIONS 
 Need for a Consistent Vocabulary 
 General Classes of Power Quality Problems 
 Transients 
 Long-Duration Voltage Variations 
 Short-Duration Voltage Variations 
 Voltage Imbalance 
 Waveform Distortion 
 Voltage Fluctuation 
 Power Frequency Variations 
 Power Quality Terms 
 Ambiguous Terms 
 CBEMA and ITI Curves 
 References 
 
 CHAPTER 3: VOLTAGE SAGS AND INTERRUPTIONS 
 Sources of Sags and Interruptions 
 Estimating Voltage Sag Performance 
 Fundamental Principles of Protection 
 Solutions at the End-User Level 
 Evaluating the Economics of Different Ride-Through Alternatives 
 Motor-Starting Sags 
 Utility System Fault-Clearing Issues 
 References 
 
 CHAPTER 4: TRANSIENT OVERVOLTAGES 
 Sources of Transient Overvoltages 
 Principles of Overvoltage Protection 
 Devices for Overvoltage Protection 
 Utility Capacitor-Switching Transients 
 Utility System Lightning Protection 
 Managing Ferroresonance 
 Switching Transient Problems with Loads 
 Computer Tools for Transients Analysis 
 References 
 
 CHAPTER 5: FUNDAMENTALS OF HARMONICS 
 Harmonic Distortion 
 Voltage versus Current Distortion 
 Harmonics versus Transients 
 Harmonic Indexes 
 Harmonic Sources from Commercial Loads 
 Harmonic Sources from Industrial Loads 
 Locating Harmonic Sources 
 System Response Characteristics 
 Effects of Harmonic Distortion 
 Interharmonics 
 References 
 Bibliography 
 
 CHAPTER 6: APPLIED HARMONICS 
 Harmonic Distortion Evaluations 
 Principles for Controlling Harmonics 
 Where to Control Harmonics 
 Harmonic Studies 
 Devices for Controlling Harmonic Distortion 
 Harmonic Filter Design: A Case Study 
 Case Studies 
 Standards of Harmonics 
 References 
 Bibliography 
 
 CHAPTER 7: LONG-DURATION VOLTAGE VARIATIONS 
 Principles of Regulating the Voltage 
 Devices for Voltage Regulation 
 Utility Voltage Regulator Application 
 Capacitors for Voltage Regulation 
 End-User Capacitor Application 
 Regulating Utility Voltage with Distributed Resources 
 Flicker 
 References 
 Bibliography 
 
 CHAPTER 8: POWER QUALITY BENCHMARKING 
 Introduction 
 Benchmarking Process 
 RMS Voltage Variation Indices 
 Harmonics Indices 
 Power Quality Contracts 
 Power Quality Insurance 
 Power Quality State Estimation 
 Including Power Quality in Distribution Planning 
 References 
 Bibliography 
 
 CHAPTER 9: DISTRIBUTED GENERATION AND POWER QUALITY 
 Resurgence of DG 
 DG Technologies 
 Interface to the Utility System 
 Power Quality Issues 
 Operating Conflicts 
 DG on Distribution Networks 
 Siting DGDistributed Generation 
 Interconnection Standards 
 Summary 
 References 
 Bibliography 
 
 CHAPTER 10: WIRING AND GROUNDING 
 Resources 
 Definitions 
 Reasons for Grounding 
 Typical Wiring and Grounding Problems 
 Solutions to Wiring and Grounding Problems 
 Bibliography 
 
 CHAPTER 11: POWER QUALITY MONITORING 
 Monitoring Considerations 
 Historical Perspective of Power Quality Measuring Instruments 
 Power Quality Measurement Equipment 
 Assessment of Power Quality Measurement Data 
 Application of Intelligent Systems 
 Power Quality Monitoring Standards 
 References 
 Index 
1
Introduction
Both electric utilities and end users of electric power are becoming
increasingly concerned about the quality of electric power. The term
power quality has become one of the most prolific buzzwords in the
power industry since the late 1980s. It is an umbrella concept for a mul-
titude of individual types of power system disturbances. The issues
that fall under this umbrella are not necessarily new. What is new is
that engineers are now attempting to deal with these issues using a
system approach rather than handling them as individual problems.
There are four major reasons for the increased concern:
1. Newer-generation load equipment, with microprocessor-based con-
trols and power electronic devices, is more sensitive to power qual-
ity variations than was equipment used in the past.
2. The increasing emphasis on overall power system efficiency has
resulted in continued growth in the application of devices such as
high-efficiency, adjustable-speed motor drives and shunt capacitors
for power factor correction to reduce losses. This is resulting in
increasing harmonic levels on power systems and has many people
concerned about the future impact on system capabilities.
3. End users have an increased awareness of power quality issues.
Utility customers are becoming better informed about such issues as
interruptions, sags, and switching transients and are challenging
the utilities to improve the quality of power delivered.
4. Many things are now interconnected in a network. Integrated
processes mean that the failure of any component has much more
important consequences.
Chapter
1
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The common thread running though all these reasons for increased
concern about the quality of electric power is the continued push for
increasing productivity for all utility customers. Manufacturers want
faster, more productive, more efficient machinery. Utilities encourage
this effort because it helps their customers become more profitable and
also helps defer large investments in substations and generation by
using more efficient load equipment. Interestingly, the equipment
installed to increase the productivity is also often the equipment that
suffers the most from common power disruptions. And the equipment
is sometimes the source of additional power quality problems. When
entire processes are automated, the efficient operation of machines and
their controls becomes increasingly dependent on quality power.
Since the first edition of this book was published, there have been
some developments that have had an impact on power quality:
1. Throughout the world, many governments have revised their laws
regulating electric utilities with the intent of achieving more cost-com-
petitive sources of electric energy. Deregulation of utilities has compli-
cated the power quality problem. In many geographic areas there is no
longer tightly coordinated control of the power from generation
through end-use load. While regulatory agencies can change the laws
regarding the flow of money, the physical laws of power flow cannot be
altered. In order to avoid deterioration of the quality of power supplied
to customers, regulators are going to have to expand their thinking
beyond traditional reliability indices and address the need for power
quality reporting and incentives for the transmission and distribution
companies.
2. There has been a substantial increase of interest in distributed
generation (DG), that is, generation of power dispersed throughout the
power system. There are a number of important power quality issues
that must be addressed as part of the overall interconnection evalua-
tion for DG. Therefore, we have added a chapter on DG.
3. The globalization of industry has heightened awareness of defi-
ciencies in power quality around