Principles of Electrical Safety

Peter E. Sutherland

ISBN: 9788126574261

408 pages

Exclusively distributed by I.K. International


INR 1395


The sections of this book are designed to provide an introduction to theory followed by a series of practical applications.  The suggested prerequisites are circuit theory, electromagnetics and power systems analysis.  The first three chapters examine the electrical fundamentals of resistance, inductance and capacitance as applied to the human body.  This is followed by an analysis of the effects of current on the human body.  Safety in substation grounding is the first practical application, focusing on step and touch potentials.  The multi-grounded distribution system and the effect of ground return currents are examined next.  The topic of arc flash hazard analysis is discussed, based upon industry standard IEEE 1584-2002.


List Of Figures

List Of Tables




Chapter 1 Mathematics Used In Electromagnetism

1.1 Introduction  

1.2 Numbers  

1.3 Mathematical Operations with Vectors

1.4 Calculus with Vectors--The Gradient

1.5 Divergence, Curl, and Stokes' Theorem

1.6 Maxwell's Equations


Chapter 2 Electrical Safety Aspects Of The Resistance Property Of Materials

2.1 Introduction

2.2 Hazards Caused by Electrical Resistance

2.3 Resistance and Conductance

2.4 Example--Trunk of a Human Body

2.5 Example--Limb of a Human Body

2.6 Power and Energy Flow

2.7 Sheet Resistivity

2.8 Example--Square of Dry Skin

2.9 Spreading Resistance

2.10 Example--Circle of Dry Skin

2.11 Particle Conductivity

2.12 Examples--Potassium, Sodium, and Chlorine Ions

2.13 Cable Resistance


Chapter 3 Capacitance Phenomena

3.1 Fundamentals of Capacitance

3.2 Capacitance and Permittivity

3.3 Capacitance in Electrical Circuits

3.4 Capacitance of Body Parts

3.5 Electrical Hazards of Capacitance

3.6 Capacitance of Cables


Chapter 4 Inductance Phenomena

4.1 Inductance in Electrical Theory

4.2 Inductance of Wires

4.3 Example--Inductance of a Conductor

4.4 Example--Inductance of Trunk and Limb

4.5 Inductors or Reactors

4.6 Skin Effect

4.7 Cable Inductance

4.8 Surge Impedance

4.9 Bus Bar Impedance Calculations


Chapter 5 Circuit Model Of The Human Body

5.1 Calculation of Electrical Shock Using the Circuit Model of the Body

5.2 Frequency Response of the Human Body  


Chapter 6 Effect Of Current On The Human Body

6.1 Introduction to Electrical Shock  

6.2 Human and Animal Sensitivities to Electric Current

6.3 Human Body Impedance

6.4 Effects of Various Exposure Conditions

6.5 Current Paths Through the Body  

6.6 Human Response to Electrical Shock Varies with Exposure Conditions, Current Magnitude, and Duration

6.7 Medical Imaging and Simulations


Chapter 7 Fundamentals Of Ground Grid Design

7.1 Introduction to Ground Grid Design  

7.2 Summary of Ground Grid Design Procedures  

7.3 Example Design from IEEE Standard 80  


Chapter 8 Safety Aspects Of Ground Grid Operation And Maintenance

8.1 Introduction  

8.2 Effects of High Fault Currents

8.3 Damage or Failure of Grounding Equipment

8.4 Recommendations


Chapter 9 Grounding Of Distribution Systems

9.1 Stray Currents in Distribution Systems  

9.2 Three-Phase Multi grounded Neutral Distribution Line

9.3 Secondary Systems: 120/240 V Single Phase  

9.4 Remediation of Stray-Current Problems  

9.5 Grounding and Overvoltages in Distribution Systems

9.6 High-Resistance Grounding of Distribution Systems  

9.6.1 Methods of Determining Charging Current


Chapter 10 Arc Flash Hazard Analysis

10.1 Introduction to Arc Flash Hazards  

10.2 Factors Affecting the Severity of Arc Flash Hazards

10.3 Example Arc Flash Calculations  

10.4 Remediation of Arc Flash Hazards  

10.5 Coordination of Low-Voltage Breaker Instantaneous Trips for Arc Flash Hazard Reduction

10.6 Low-Voltage Transformer Secondary Arc Flash Protection using Fuses


Chapter 11 Effect Of High Fault Currents On Protection And Metering

11.1 Introduction  

11.2 Current Transformer Saturation

11.3 Saturation of Low-Ratio CTs  

11.4 Testing of Current Transformer Saturation

11.5 Effect of High Fault Currents on Coordination  

11.6 Protective Relay Ratings and Settings

11.7 Effects of Fault Currents on Protective Relays  

11.8 Methods for Upgrading Protection Systems  


Chapter 12 Effects Of High Fault Currents On Circuit Breakers

12.1 Insufficient Interrupting Capability

12.2 High Voltage Air Circuit Breakers  

12.3 Vacuum Circuit Breakers  

12.4 SF6 Circuit Breakers  

12.5 Loss of Interruption Medium  

12.6 Interrupting Ratings of Switching Devices

12.7 Circuit Breakers

12.8 Fuses

12.9 Case Studies

12.10 Low-Voltage Circuit Breakers

12.11 Testing of Low-Voltage Circuit Breakers

12.12 Testing of High-Voltage Circuit Breakers


Chapter 13 Mechanical Forces And Thermal Effects In Substation Equipment Due To High Fault Currents

13.1 Introduction

13.2 Definitions

13.3 Short-Circuit Mechanical Forces on Rigid Bus Bars

13.4 Dynamic Effects of Short Circuits

13.5 Short-Circuit Thermal Effects

13.6 Flexible Conductor Buses

13.7 Force Safety Devices

13.8 Substation Cable and Conductor Systems

13.9 Distribution Line Conductor Motion

13.10 Effects of High Fault Currents on Substation Insulators

13.11 Effects of High Fault Currents on Gas-Insulated Substations (GIS)


Chapter 14 Effect Of High Fault Currents On Transmission Lines

14.1 Introduction

14.2 Effect of High Fault Current on Non-Ceramic Insulators (NCI)

14.3 Conductor Motion Due to Fault Currents

14.4 Calculation of Fault Current Motion for Horizontally Spaced Conductors

14.5 Effect of Conductor Shape

14.6 Conductor Equations of Motion

14.7 Effect of Conductor Stretch

14.8 Calculation of Fault Current Motion for Vertically Spaced Conductors

14.9 Calculation Procedure

14.10 Calculation of Tension Change with Motion

14.11 Calculation of Mechanical Loading on Phase-to-Phase Spacers

14.12 Effect of Bundle Pinch on Conductors and Spacers


Chapter 15 Lightning And Surge Protection

15.1 Surge Voltage Sources and Wave shapes

15.2 Surge Propagation, Refraction, and Reflection

15.3 Insulation Withstand Characteristics and Protection

15.4 Surge Arrester Characteristics

15.5 Surge Arrester Application