Elements of Power Systems

Introductory
Introduction
Significance of Electrical Energy
Basic Concepts of Power System
Single-Line Diagram of a Power Supply Network
Different Types of Energy Sources

Per-Unit Systems
Introduction
Per-Unit Representation of Basic Electrical Quantities
Change of Base
Per-Unit Quantities in a Three-Phase System
Base Quantities in Terms of kV and MVA
Per-Unit Impedance of a Transformer
Advantages of pu Representation
Worked Examples

Load Characteristics
Introduction
Load
Variable Load
Connected Load
Demand
Demand Interval
Maximum Demand or Peak Load
Demand Factor
Average Load or Average Demand
Load Factor
Diversity Factor
Plant Capacity Factor
Plant Use Factor
Units Generated Per Annum
Loss Factor
Load Curves
Information Obtained From Load Curves
Load Duration Curve
Information Available From Load Duration Curve
Worked Examples

Tariffs
Introduction
Objectives of Tariff
Desirable Characteristics of a Tariff
Types of Tariff
Worked Examples

Mechanical Design of Overhead Line
Introduction
Conductor Material
Line Supports
Indian Electricity Rules (1956) for Overhead Lines
Sag in Overhead Lines
Calculation of Sag
Sag Template
Stringing Chart
Worked Examples

Overhead Line Insulators
Introduction
Insulator Materials
Types of Insulators
Potential Distribution over Suspension Insulator String
String Efficiency
Mathematical Expression
Methods of Improving String Efficiency
Effects of Rain on the String Efficiency
Worked Examples

Corona
Introduction
The Phenomenon of Corona
Theory of Corona Formation
Factors Affecting Corona
Advantages of Corona
Disadvantages
Methods of Reducing Corona Effect
Critical Disruptive Voltage
Visual Critical Voltage
Power Loss Due to Corona
Radio Interference
Inductive Interference between Power and Communication Lines
Worked Examples

Transmission Line Parameters
Introduction
Line Inductance
Flux Linkage Due to a Single Current-Carrying Conductor
Inductance of a Single-Phase Two-Wire Line
Flux Linkages of One Conductor in a Group of Conductors
Inductance of Three-Phase Overhead Line with Unsymmetrical Spacing
Inductance of Three-Phase Line with More than One Circuit
Capacitance
Potential at a Charged Single Conductor
System of Conductors
Capacitance of a Single-Phase Two-Wire Line
Capacitance of a Three-Phase Overhead Lines
Effect of Earth on the Transmission Line Capacitance
Bundled Conductor
Skin Effect
Proximity Effect
Worked Examples

Performance of Transmission Lines
Introduction
Classification of Lines
Performance of Single-Phase Short Transmission Line
Short Three-Phase Line
Transmission Line as Two Port Network
Line Regulation
Line Efficiency
Performance of Medium Transmission Line
Calculation of Transmission Efficiency and Regulation of Medium Line
Long Transmission Line
Evaluation of ABCD Constants
Ferranti Effect
ABCD Constants
Worked Examples

Underground Cables
Introduction
Insulating Materials for Cables
Construction of Cables
Classification of Cable
Cables for Three-Phase Service
Laying of Underground Cables
Insulation Resistance of a Single-Core Cable
Capacitance of a Single-Core Cable
Dielectric Stress in a Single-Core Cable
Most Economical Conductor Size in a Cable
Grading of Cables
Capacitance in a Three-Core-Belted Cable
Measurement of C_c and C_s
Current-Carrying Capacity
Thermal Resistance
Thermal Resistance of Dielectric of a Single-Core Cable
Types of Cable Faults
Loop Tests for Location of Faults in Underground Cables
Worked Examples

Distribution System
Introduction
Classification of Distribution Systems
DC Distribution
Connection Schemes of Distribution System
Types of DC Distributors
DC Distribution Calculations
DC Distributor Fed at One End—Concentrated Loading
DC Distributor Fed at One End—Uniformly Loaded
Distributor Fed at Both Ends—Concentrated Loading
Distributor Fed at Both Ends—Uniformly Loaded
Ring Distributor
Ring Main Distributor with Interconnector
AC Distribution
AC Distribution Calculation
Methods of Solving AC Distribution Problems
Worked Examples

Fault Analysis
Introduction
Classification of Faults
Symmetrical Component Method
Significance of Positive-, Negative-, and Zero-Sequence Components
Operator (a)
Voltage of the Neutral
Sequence Network Equations
Sequence Impedances of Power System Elements
Analysis of Unsymmetrical Faults
Single Line-to-Ground Fault (L-G)
Line-to-Line Fault
Double Line-to-Ground Fault
L-L-L Fault/Three-Phase Fault/Symmetrical Fault
Worked Examples

Circuit Breakers
Introduction
Difference between CB and Fuse
Operating Principle of CB
Arc Phenomenon
Principles of Arc Extinction
Methods of Arc Extinction
Some Important Definitions
Expression for Restriking Voltage Transients
Current Chopping
Resistance Switching
CB Ratings
Autoreclosing
Classification of CBs
Oil CBs
Types of Oil CBs
Plain-Break Oil CBs
Arc Control Oil CBs
Low-Oil CBs
Maintenance of Oil CBs
Air-Blast CBs
Types of Air-Blast CB
Vacuum CBs
SF₆ CBs
High-Voltage DC CB
Worked Examples

Different Types of Relays
Introduction
Essential Qualities of Protection
Classification of Relay
Basic Relay Terminology
Zones of Protection
Primary and Backup Protection
Classification of Protective Scheme
Construction and Operating Principles of Relay
Overcurrent Protection
Time–Current Characteristics
Current Setting
Plug Setting Multiplier
Time Multiplier Setting
Overcurrent Protection Scheme
Directional Power or Reverse Power Relay
Directional Overcurrent Relay
Protection of Parallel Feeder
Protection of Ring Mains
Earth Fault Protection Scheme
Distance Protection Scheme
Impedance Relay
Reactance Relay
mho Type Distance Relay
Universal Torque Equation
Differential Relays
Simple Differential Relay
Percentage Differential Relay
Balanced Voltage Differential Relay
Translay Relay
Worked Examples

Protection of Alternator and Transformers
Introduction
Protection of Alternators
Stator Protection
Rotor Protection
Miscellaneous
Transformer Protection
Percentage Differential Protection
Overheating Protection
Rate of Rise of Pressure Relay
Overcurrent Protection
Overfluxing Protection
Earth Fault Protection
Buchholz Relay
Generator-Transformer Unit Protection
Worked Examples

Travelling Wave
Introduction
Surge Impedance and Velocity of Propagation
Reflection and Refraction of Waves
Receiving End Transmission Operating on No-Load Condition
Receiving End Operating on Short Circuit Condition
Reflection and Refraction at a T-Junction
Worked Examples

Earthing
Introduction
Objects of Earthing
Classification of Earthing
Isolated Neutral or Undergrounded Neutral
Advantages of Neutral Grounding
Methods of Neutral Grounding
Worked Examples

Substation
Introduction
Substation
Classification of Substations
Comparison between Outdoor and Indoor Substations
Transformer Substations
Equipment in a Transformer Substation
Bus-Bar Arrangements in Substations
Key Diagram of 11 kV/400 V Indoor Substation

Power System Stability
Introduction
Stability Limits and Power Transmission Capability
Infinite Bus
Synchronous Generator Connected to an Infinite Bus
Powers-Angle Curve
Power Angle Relations for General Network Configuration
Steady-State Stability Criterion
Transient Stability
Swing Equation
Swing Curves
M and H Constants
Equivalent System
Equivalent M Constant of Two Machines
Equal-Area Criterion of Stability
System Fault and Subsequent Circuit Isolation
Methods of Improving Stability
Worked Examples

Load Flows
Introduction
Bus Classification
Bus Admittance Matrix
Development of Static Load Flow Equation
Gauss–Seidel Iterative Technique
GS Method of Solution of Load Flow Equation using Ybus
Newton–Raphson Method for Load Flow Solution
Comparison of Load Flow Analysis Methods
Worked Examples

Biography

Pradip Kumar Sadhu holds bachelor, post-graduate, and Ph.D degrees in electrical engineering from Jadavpur University, West Bengal, India. Dr. Sadhu has 18 years of experience in teaching and industry. Currently, he is a professor and head of the Electrical Engineering Department of the Indian School of Mines, Dhanbad, where he has guided a large number of doctoral candidates and M.Tech students. He holds four patents, has been published in several national and international journals and conference proceedings, and is principal investigator of a number of government-funded projects.

Soumya Das holds a B.Tech from the West Bengal University of Technology and an ME from Jadavpur University, West Bengal, India. He is currently pursuing his Ph.D with the Department of Electrical Engineering at the Indian School of Mines, Dhanbad. He is also an assistant professor in the Electrical Engineering Department of the University Institute of Technology, Burdwan University, West Bengal, India, where he has guided a large number of B.Tech and M.Tech students. Previously, he was an assistant professor in the Electrical Engineering Department at the Bengal Institute of Technology and Management, Santiniketan, India.

"… a very good contribution that covers many aspects of power systems and components. … I strongly believe that this book will be interesting for students and professionals in electrical power engineering."
—Dr. Dipl.-Ing. M. Popov, Delft University of Technology (TU Delft), Netherlands

"… provides an important resource for engineers, instructors, applied researchers, and students in the field of power engineering. … This well-written book offers broad coverage of important issues, operating concepts, and control techniques commonly addressed in most textbooks regarding power systems."
—Dr. Chao-Tsung Ma, Department of Electrical Engineering, CEECS, National United University, Miaoli City, Taiwan

"... a very good choice as a complete reference for power systems. Readers will find it worthwhile for their collections and self-reading material."
—Prof. R. P. Maheshwari, Department of Electrical Engineering, Indian Institute of Technology, Roorkee

"This book offers a simplified and summarized presentation of the majority of topics related to electric power systems. Sadhu (Indian School of Mines) and Das (Burdwan Univ., India) review and briefly discuss the foundations of a particular area in each of the book's 20 chapters. The first four chapters are an overview of basic concepts and terminologies employed in power systems engineering. The next six chapters focus on power overhead transmission lines and underground cables. They also cover issues related to transmission lines, such as corona and electrical insulation. Electric power distribution systems, earthing, and substations are presented in separate chapters. The book goes on to discuss elements of power system protection, including relays, circuit breakers, and fault analysis. Concluding chapters deal with power system stability and load flow. The authors have reduced the mathematical and physical complexities that one may encounter in each of these topics as much as possible, allowing the general reader with some background in power systems to benefit from the book. The worked examples and end-of-chapter questions are very helpful for understanding the material."
—CHOICE, July 2016 Issue