Industrial Power Distribution

Ralph Fehr

• Publisher: Wiley-IEEE Press
• Year: 2015
• Print ISBN: 9781119063346
• eBook ISBN: 9781119065081
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Power Resources
• Index: Technology & Engineering

This new edition of Industrial Power Distribution addresses key areas of electric power distribution from an end-user perspective, which will serve industry professionals and students develop the necessary skills for the power engineering field.

• Expanded treatment of one-line diagrams, the per-unit system, complex power, transformer connections, and motor applications
• New topics in this edition include lighting systems and arc flash hazard
• Concept of AC Power is developed step by step from the basic definition of power
• Fourier analysis is described in a graphical sense
• End-of-chapter exercises

If you are an instructor and adopted this book for your course, please email [email protected] to get access to the instructor files for this book.

CHAPTER 1
Utility Source

OBJECTIVES

• Be aware of the need to always exercise safety while working around electricity
• Understand the significance of the voltage level at the point of delivery to the industrial customer
• Be proficient in the use of one-line diagrams to represent a three-phase electrical system
• Understand the concept of protection zones
• Recognize various source configurations and know the advantages and disadvantages of each
• Calculate per-unit quantities, convert between actual and per-unit quantities, and be able to apply the per-unit system to do electrical calculations
• Understand the components of power in an AC system
• Be able to calculate voltage drop in a balanced three-phase system
• Understand the significance of short circuit availability, both from a fault interrupting standpoint and from a motor starting standpoint
• Comprehend the importance of properly sizing conductors and supply transformers

1.1 ELECTRICAL SAFETY

A 6-W night light bulb draws 50 mA of current. Even this small magnitude of current can kill a person. Humans can perceive an electric current as small as 0.5 mA. As the current magnitude rises to the 1–5 mA range, muscles will contract. Currents in the 3–10 mA range cause pain. Currents in the 10–40 mA range fall in the “let go” threshold, meaning they will cause muscles to contract so tightly that “letting go” of a grasped wire becomes impossible. Respiratory paralysis can occur in the 30–75 mA range. The heart will be affected with ventricular fibrillation occurring in the 75–100 mA range and heart paralysis occurring in the 250–300 mA range. Note that we have not yet reached one-third of an ampere! In the range of 5–6 A, organ burns will occur. These typical values are summarized in Figure 1.1.

Figure 1.1 Effects of Electrical Current on the Human Body

Although electrocution is a major concern when working around electricity, most electrical injuries are the result of burns occurring when large amounts of thermal energy are released during arcing faults. Electric arc flash presents a hazard that is distinct from electric shock. The heat and blast released during a short circuit fault can injure or kill a person located many feet from the fault location and who never come in contact with an energized conductor. The arc flash hazard will be discussed in Section 7.5.

Because of the shock and burn hazards posed by electricity, safety must always be exercised and considered as the highest priority when working around electrical equipment. Nothing supersedes safety. Carelessness for even a moment could result in a serious injury—or worse.

Much of what is considered safe working practices falls soundly into the category of common sense. For example, do not assume a circuit is de-energized—test it and ground it to make sure. Follow all grounding and bonding requirements when performing maintenance of electrical equipment. Stringently adhere to all switching and tagging practices required by the owner of the facility in which you are working. Be aware of working clearances and approach boundaries (these topics will be discussed in Section 7.5). Be sure that all tools and equipment including personal protective equipment (PPE) are in good condition, are being used properly, and have current testing or certification credentials, if applicable. Adhere to all safety procedures, even if the procedure does not seem important to you. It probably is important, but even if it is not, better safe than sorry. And be sure to complete all required training, including refresher courses, required for your job.

Electricity need not be feared, but certainly does command respect. Safe working practices need to be standard operating procedure and never be compromised. Safety must also be considered when designing electrical systems. Engineering additional safety features beyond what is minimally required for a system is a hallmark of excellent design. If an unsafe condition is discovered, it needs to be reported and made safe as quickly as possible. Take safety seriously—your life depends on it!

1.2 DELIVERY VOLTAGE

Electric...

Table of contents

• COVER
• IEEE PRESS
• TITLE PAGE
• COPYRIGHT
• PREFACE
• PREFACE TO THE FIRST EDITION
• ACKNOWLEDGMENTS
• ABOUT THE AUTHOR
• CHAPTER 1 UTILITY SOURCE
• CHAPTER 2 INSTRUMENT TRANSFORMERS AND METERING
• CHAPTER 3 TRANSFORMER CONNECTIONS
• CHAPTER 4 FAULT CALCULATIONS
• CHAPTER 5 PROTECTIVE DEVICE SELECTION AND COORDINATION
• CHAPTER 6 RACEWAY DESIGN
• CHAPTER 7 SWITCHGEAR AND MOTOR CONTROL CENTERS
• CHAPTER 8 LADDER LOGIC
• CHAPTER 9 MOTOR APPLICATION
• CHAPTER 10 LIGHTING SYSTEMS
• CHAPTER 11 POWER FACTOR CORRECTION
• CHAPTER 12 POWER QUALITY
• APPENDIX A UNITS OF MEASUREMENT
• APPENDIX B CIRCUIT ANALYSIS TECHNIQUES
• APPENDIX C PHASORS AND COMPLEX NUMBER MATHEMATICS
• APPENDIX D IMPEDANCE DATA
• APPENDIX E AMPACITY DATA
• APPENDIX F CONDUIT DATA
• INDEX
• IEEE PRESS SERIES ON POWER ENGINEERING
• EULA