Electric Power Transmission & Distribution

Cover
Electric power
Transmission
And distribution
	Copyright
Contents
Preface
Acknowledgement
Transmission And Distribution: An Introduction
	Overview
	Various Levels of Power Transmissiona
	Conventional Sources of Electrical Energy
		Hydro Power Stations
		Thermal Power Stations
		Nuclear Power Stations
		Diesel Power Stations
	Load Forecasting
		Purpose of Load Forecasting
		Classification of Load Forecasting
		Forecasting Procedure
		Load Characteristics
	Load Modelling
		Characteristics of Load Models
	Star-Connected Loads
		Constant Power Model
		Constant Current Model
		Constant Impedance Model
	Deregulation
		Need for Restructuring
		Motivation for Restructuring the Power Industry
	Distribution Automation
Transmission-Line Parameters
	Introduction
	Conductor Materials
	Types of Conductors
	Bundled Conductors
	Resistance
	Current Distortion Effect
		Skin Effect
		Proximity Effect
		Spirality Effect
	Inductance
		Inductance of a Conductor due to Internal Flux
		Inductance of a Conductor due to External Flux
	Inductance of a Single-Phase Two-Wire System
	Flux linkages with one sub-conductor of a composite
Conductor
	Inductance of a single-phase system (with composite
Conductors)
	Inductance of Three-Phase Lines
		Equivalent (Symmetrical) Spacing
		Unsymmetrical Spacing (Untransposed
		Transposition of Overhead Lines
		Unsymmetrical Spacing (Transposed)
	Inductance of Three-Phase Double Circuit Line
		Inductance of Three-phase Double-Circuit Line with Symmetrical Spacing (Hexagonal)
		Inductance of a Three-phase Transposed Double-Circuit Line with Unsymmetrical Spacing
	Capacitance
	Potential Difference Between Two Points Due to a Charge
	Capacitance of a Single-Phase Line (Two-Wire Line)
	Potential difference between two conductors of a group
of charged conductors
	Capacitance of Three-Phase Lines
		Equilateral Spacing
		Capacitance of an Unsymmetrical Three-phase System (Transposed)
	Capacitance of a Three-Phase Double-Circuit Line
		Hexagonal Spacing
		Flat Vertical Spacing (Unsymmetrical Spacing)
	Effect of Earth on Transmission Line Capacitance
		Capacitance of a Single Conductor
		Capacitance of a Single-phase Transmission Line
		Capacitance of Three-phase Line
Performance of short and medium
Transmission lines
	Introduction
	Representation of Lines
	Classification of Transmission Lines
	Short Transmission Line
		Effect of Power Factor on Regulation and Efficiency
	Generalised Network Constants
	A, B, C, D Constants For Short Transmission Lines
	Medium Transmission Line
		Load End Capacitance Method
		Nominal-T Method
		Nominal-π Method
Performance of Long Transmission Lines
	Introduction
	Rigorous Solution
	Interpretation of The Long Line Equations
		Propagation Constant
		Wave Length and Velocity of Propagation
	Evaluation of Transmission Line Constants
	Regulation
	Equivalent Circuit Representation of Long Lines
		Representation of a Long Line by Equivalent- π Model
		Representation of a Long Line by Equivalent-T Model
	Tuned Transmission Lines
	Characteristic Impedance
	Surge Impedance Loading
	Ferranti Effect
	Constant Voltage Transmission
	Charging Current in Lines
		Power Loss Due to Charging Current (or Open-Circuited Line)
	Line Loadability
	Power Flow Through a Transmission Line
	Circle Diagram
		Receiving-end Phasor Diagram
		Receiving-end Power Circle Diagram
		Analytical Method for Receiving-end Power Circle Diagram
		Sending-end Power Circle Diagram
		Analytical Method for Sending-end Power Circle Diagram
Transmission Line Transients
	Introduction
	Types of System Transients
	Travelling Waves on a Transmission Line
	The Wave Equation
	Evaluation of Surge Impedance
	Importance of Surge Impedance
	Travelling Wave
	Evaluation of Velocity of Wave Propagation
	Reflection and refraction coefficient (line terminated Through a resistance)
		Line Open-Circuited at the Receiving End
		Line Short-Circuited at the Receiving End
		Line Connected to a Cable
		Reflection and Refraction at a T-Junction
		Reactance Termination
			Line Terminated Through Capacitance
			Line Terminated Through Inductance
		Bewley’s Lattice Diagram
Corona
	Introduction
	Theory Of Corona Formation (Corona Discharge
	Electric Stress
	Critical Disruptive Voltage
	Visual Critical Voltage
	Power Loss Due to Corona
	Factors Affecting Corona Loss
		Electrical Factors
		Atmospheric Factors
		Factors Related to the Conductors
	Methods For Reducing Corona Loss
	Advantages and Disadvantages of Corona
	Effect of Corona on Line Design
	Radio Interference
	Audio Noise
	Interference With Communication Lines
		Electromagnetic Effect
		Electrostatic Effect
		Corona Phenomena in HVDC Lines
Mechanical Design of Transmission Line
	Introduction
	Factors Affecting Mechanical Design
	Line Supports
		Wooden Poles
		Tubular Steel Poles
		RCC Poles
		Latticed Steel Towers
	Sag
		Calculation of Sag at Equal Supports
		Effect of Ice Covering and Wind Pressure
		Safety Factor
		Calculation of Sag at Different Level Supports
	Stringing Chart
	Effects and prevention of vibrations (vibrations
And dampers)
	Sag Template
	Conductor Spacing and Ground Clearance
Overhead Line Insulators
	Introduction
	Insulator Materials
	Types of Insulators
		Pin Type Insulators
		Suspension Type Insulator
		Strain Insulator
		Shackle Type Insulator
	Potential Distribution Over a String of Suspension Insulators
		Mathematical Expression for Voltage Distribution
	String Efficiency
	Methods Of Improving String Efficiency
		Selection of m
		Grading of Units
		Guard Ring or Static Shielding
	Arcing Horn
	Testing of Insulators
		Flashover Tests
		Performance Test
		Routine Tests
	Causes of Failure of Insulators
Underground Cables
	Introduction
	General Construction of a Cable
	Types of Cables
		Low Tension Cables
		High Tension Cables
		Super Tension Cables
		Extra High Tension Cables
	Advantages and disadvantages of underground cables over
Overhead lines
	Properties of Insulating Materials For Cables
		Insulating Materials
	Insulation Resistance of Cables
	Capacitance of a Single-Core Cable
	Dielectric Stress in a Cable
	Economical Core Diameter
	Grading of Cables
		Capacitance Grading
		Intersheath Grading
		Practical Aspects of Cable Grading
	Power Factor in Cables (Dielectric Power Factor)
	Capacitance of a Three-Core Cable
		Measurement Of Cc And Cs
	Heating of Cables
		Generation of Heat Within the Cables
	Thermal Characteristics
		Current Capacity
	Testing of Cables
		Acceptance Tests at Works
		Sample Tests at Working
		Performance Tests
		Tests on Oil-Filled and Gas-Filled Cables
		Tests When Installed
		Tests on Pressurized Cables
	Laying of Cables
		Direct System
		Draw-in System
		Solid Systems
	Cable Faults
	Determination of maximum current carrying capacity
of cables
Power Factor Improvement
	Introduction
	Power Factor
		Causes of Low Power Factor
		Effects or Disadvantages of Low Power Factor
	Advantages of Power Factor Improvement
	Methods of Improving Power Factor
		Static Capacitor
		Synchronous Condenser
		Phase Advancers
	Most economical power factor when the kilowatt
Demand is constant
	most economical power factor when the kva
maximum demand is constant
Voltage Control
	Introduction
	Necessity of Voltage Control
	Generation and Absorption of Reactive Power
	Location of Voltage Control Equipment
	Methods of Voltage Control
		Excitation Control
		Shunt Capacitors and Reactors
		Series Capacitors
		Tap Changing Transformers
		Booster Transformers
		Synchronous Condensers
	Rating of Synchronous Phase Modifier
Electric Power Supply Systems
	Introduction
	Comparison of Conductor Efficiencies For Various Systems
		Overhead Lines
		Cable Systems
	Choice of System Frequency
	Choice of System Voltage
	Advantages of High-Voltage Transmission
	Effect of Supply Voltage
	Economic Size of Conductor (Kelvin’s Law)
		Modification of Kelvin’s Law
		Practical Limitations to the Application of Kelvin’s Law
Substations
	Introduction
	Factors Governing The Selection of Site
	Classification of Substation
		According to Service
		According to Design
	Merits and Demerits of Indoor and Outdoor Substations
	Substation Equipment
	Types of Bus Bar Arrangements
		Single Bus Bar
		Single-Bus Bar System with Sectionalization
		Double Bus Bar with Single Breaker
		Double Bus Bar with Two Circuit Breakers
		Breakers and a Half with Two Main Buses
		Main and Transfer Bus Bar
		Double Bus Bar with Bypass Isolator
		Ring Bus
	Pole and Plinth-Mounted Transformer Substations
	Optimal Substation Location
		Perpendicular Bisector Rule
	Basic Terms of Earthing
	Grounding or Neutral Earthing
	Earthing of Substations
	Methods of Neutral Grounding
		Solid Grounding or Effective Grounding
		Resistance Grounding
		Reactance Grounding
		Peterson-coil Grounding
		Grounding Transformer
	Grounding Grid
Distribution Systems
	Introduction
	Primary and Secondary Distribution
		Primary Distribution
		Secondary Distribution
	Design Considerations in a Distribution System
	Distribution system losses
		Factors Effecting Distribution-System Losses
		Methods for the Reduction of Line Losses
	Classification of Distribution System
		Type of Current
		Type of Construction
		Type of Service
		Number of Wires
		Scheme of Connection
	Radial Distribution System
	Ring Or Loop Distribution System
	Interconnected Distribution System
	DC Distribution
		Distributor Fed at One End with Concentrated Loads
		Distributor Fed at Both Ends with Concentrated Loads
		Uniformly Loaded Distributor Fed at One End
		Uniformly Distributed Load Fed at Both Ends at the Same Voltage
		Uniformly Distributed Load Fed at Both Ends at Different Voltages
	Ring Distribution
		Advantages of Using Interconnector
	Stepped Distributor
	AC Distribution
		Power Factor Referred to the Receiving-end
		Power Factor Referred to Respective Load Voltages
		AC Three-Phase Distribution
EHV and HVDC Transmission Lines
	Introduction
	Need of EHV transmission lines
	Advantages and disadvantages of ehv lines
	Methods of increasing transmission capability of EHV lines
	HVDC transmission system
	Comparison Between AC and DC Transmission Systems
		Economic Advantages
		Technical Advantages
	Advantages and Disadvantages of HVDC Systems
	HVDC Transmission System
		Monopolar Link
		Bipolar Link
		Homopolar Link
	Rectification
	Three-Phase Bridge Converter
	Inversion
	Components of HVDC Transmission System
	Harmonic Filters
	Application Of HVDC Transmission System
Flexible AC Transmission Systems
	Introduction
	Facts
	Facts Controllers
		Shunt-Connected Controllers
		Series-Connected Controllers
		Combined Shunt and Series-Connected Controllers
	Control of Power Systems
		FACTS Devices
		Benefits of Control of Power Systems
		FACTS Technology: Opportunities
	Basic Relationship For Power-Flow Control
		Shunt Compensator
		Thyristor-Controlled Reactor (
		Thyristor-Switched Capacitor
		Series Compensator
		Unified Power-Flow Controller
	“Facts” For Minimizing Grid Investments
	Voltage Stability
		Voltage Stability – What is it?
		Derivation of Voltage Stability Index
Appendices
	Appendix1
	Appendix2
	Appendix3
	Appendix4
Glossary
Bibliography
Index