Paithankar Y.G. Bhide S.R. Fundamentals of Power System Protection

Prentice-Hall of lndia Private Limited, New Delhi. 2003. 302 с.Fundamentals of Power System Protection is the most commonly use book for electrical engineers
Dependence of Modern Society on Electric Supply I
Faults and Abnormal Operating Conditions I
Shunt Faults (Short Circuits)
Causes of Shunt Faults
Effects of Shunt Faults
Classification of Shunt Faults
Phase Faults and Ground Faults
Phasor Diagram of Voltages and Currents During Various Faults
Series Faults
Abnormal Operating Conditions
Should Protective Relays Trip During Abnormal Operating Conditions?
Can Protective Relays Prevent Faults?
What are Protective Relays Supposed to Do
volution of Power Systems
Isolated Power System
Interconnected Power System
Negative Synergy of an Interconnected System
ates of Operation of a Power System
From Natural Monopoly to the Deregulated Power System
Protection System and Its Attributes
Sensitivity
Selectivity
Reliability and Dependability
ystem Transducers
Current Transformer
Circuit Breaker
Trip Circuit of a CB
Organization of Protection
Zones of Protection
Primary and Back-up Protection
Maloperations
Various Power System Elements That Need Protection
Various Principles of Power System Protection
Reuiew Questions
ProblemsFuse
Thermal Relays
er-current Relay
Instantaneous OC Relay
Definite Time Over-current Relay
Inverse Time Over-current Relay
Implementation of Over-current Relay Using Induction Disk
Application of Definite Time OC Relays for Protection of a
Distribution Feeder
Application of Inverse Definite Minimum Time Relay on a
Distnbution Feeder
Choice Between IDMT and DTOC Relays
Protection of a Three-phase Feeder
Directional Over-current Relay
Other Situations Where Directional OC Relays are Necessary
Phasor Diagram for Voltage and Current for Forward and
Reverse Fault (Single-phase System)
Application of Directional Relay to a Three-phase Feeder
Directional OC Protection of a Three-phase Feeder
Directional Protection Under Non-fault Conditions *
(Reverse Power Relay)
Drawbacks of Over-current Relays
Reuzew Questions
Simple Differential Protection
Simple Differential Protection: Behaviour During Load 59 I
Simple Differential Protection: Behaviour During External Fault 60 I
Simple Differential Protection: Behaviour During Internal Fault
Simple Differential Protection, Double-end-fed: Behaviour
I During Internal Fault
Zone of Protection of the Differential Relay
Actual Behavlour of a Simple Dlfferentlal Scheme
Through Fault Stability and Stabillcy Ratio
Equivalent Circuit of CT
Percentage Differential Relay
Block Diagram of Percentage Differential Relay
Earth Leakage Protection
Earth Leakage Protection for Single-phase Load
Earth Leakage Protection for Three-phase Loads
Reuzew QuestLons
Types of Transformers
Phasor Diagram for a Three-phase Transformer
Equivalent Circuit of Transformer
Types of Faults in Transformers
Over-current Protection
Percentage Differential Protection of Transformers
Development of Connections
Phase c-to-Ground (c-g) External Fault
Phase c-to-Ground (c-g) Internal Fault
Inrush Phenomenon
Percentage Differential Relay with Harmonic Restraint
High Resistance Ground Faults in Transformers
High Resistance Ground Faults on the Delta Side
High Resistance Ground Faults on the Star Side
Inter-turn Faults in Transformers
Incipient Faults in Transformers
Buchholz Relay
Analysis of Trapped Gases
Phenomenon of Over-fluxing in Transformers
Protection Against Over-fluxing
Transformer Protection Application Chart
An Illustrative Numerical Problem
Reuzew Questions
Differential Protection of Busbars
Selection of CT Ratios in Case of Busbar Protection
Wrong Method
Selection of CT Ratios in Case of Busbar Protection
Correct Method
External and Internal Fault
Actual Behaviour of a Protective CT
Circuit Model of Saturated CT
External Fault with One CT Saturated: Need for High Impedance
Busbar Protection
Minimum Internal Fault That Can Be Detected by the High
Impedance Busbar Differential Scheme
Stability Ratio of High Impedance Busbar Differential Scheme
Supervisory Relay
Protection of Three-phase Busbars
Numerical Example on Design of High Impedance Busbar Differential
Scheme
Review Questions
Drawbacks of Over-current Protection
Introduction to Distance Protection
Simple Impedance Relay
Trip Law for Simple Impedance Relay Using Universal Torque Equation
Implementation of Simple Impedance Relay Using Balanced Beam Structure
Performance of Simple Impedance Relay During Normal Load Flow
Effect of Arc Resistance on Reach of Simple Impedance Relay
Directional Property Exhibited by Simple Impedance Relay
Performance of Simple Impedance Relay During Power Swing
Reactance Relay
Trip Law for Reactance Relay Using Universal Torque Equation
Implementation of Reactance Relay Using the Induction Cup Structure
Performance of Reactance Relay During Normal Load Flow
Effect of Arc Resistance on Reach of Reactance Relay
Directional Property Exhibited by Reactance Relay
Performance of Reactance Relay During Power Swing
Mho Relay
Trip Law for Mho Relay Using Universal Torque Equation
Implementation of Mho Relay Using Induction Cup Structure
Performance of Mho Relay During Normal Load Flow
Effect of Arc Resistance on Mho Relay Reach
Directional Property Exhibited by Mho Relay
Performance of Mho Relay During Power Swing
Comparison Between Distance Relays
Distance Protection of a Three-phase Line
Phase Faults
Ground Faults
Complete Protection of a Three-phase LineVarious Faults and Abnormal Operating Conditions
Starting Current
Electrical Faults
Fault on Motor Terminals
Phase Faults Inside the Motor
Ground Faults Inside the Motor
Inter-turn Faults
Abnormal Operating Conditions from Supply Side
Unbalanced Supply Voltage
Single Phasing
Reduction in Supply Voltage
Reversal of Phases
Abnormal Operating Conditions from Mechanical Side
Failure of Bearing and Rotor Jam
Overload
Data Required for Designing Motor Protection Schemes
Review Questions
Comparison vs Computation
Amplitude Comparator
Phase comparator
The Cosine-type Phase Comparator
The Sine-type Phase Comparator
Duality Between Amplitude and Phase Comparators
Synthesis of Various Distance Relays Using Static Comparators
Synthesis of Mho Relay Using Static Phase Comparator
Synthesis of Reactance Relay Using Cosine-type Phase Comparator
Synthesis of Simple Impedance Relay Using Amplitude Comparator 210 e
Development of an Electronic Circuit for Implementing
a Cosine-type Phase Comparator
An Electronic Circuit for Implementing a Sine-type Phase Comparator
Synthesis of Quadrilateral Distance Relay
Review QuestionsBlock Diagram of Numerical Relay
Sampling Theorem
Correlation with a Reference Wave
Fourier Analysis of Analogue Signals 229 I 11.5 Least Error Squared (LES) Technique
Conrcnis vii . . 6.8 Reasons for Inaccuracy of Distance Relay Reach
Three-stepped Distance Protechon
First Step
Second Step
Third Step
Trip Contact Configuration for the Three-stepped Distance
Protection
Three-stepped Protection of Three-phase Line against All Ten Shunt
Faults
Impedance Seen from Relay Side
Three-stepped Protection of Double-end-fed Lines
Review Questions
Need for Carrier-aided Protection
Various Options for a Carrier
Coupling and Trapping the Carrier into the Desired Line Section
Single Line-to-ground Coupllng
Line-to-line Coupling
Unit Type Carrier-aided Directional Comparison Relaying
Carrier-aided Distance Schemes for Acceleration of Zone I
Transfer Trip or Inter-trip
Permissive Inter-trip
Acceleration of Zone I
Pre-acceleration of Zone I
Phase Comparison Relaylng (Unit Scheme)
Review QuestionsElectrical Circuit of the Generator
Various Faults and Abnormal Operating Conditions
Stator Faults
Stator Phase and Ground Faults
Transverse Differential Protection
Rotor Faults
Abnormal Operating Conditions
Unbalanced Loading
Over-speeding
Loss of Excltation
Protection Against Loss of Excitation Using Offset Mho Relay
Loss of Prime Mover
Revzew Questions
Digital Filtering
Simple Low-pass Filter
Simple High-pass PLlter
Finite Impulse Response (XR) Filters
Infinite Impulse Response (IIR) Filter
Comparison Between FIR and IIR Filters
Numerical Over-current Protection
Kumerical Transformer Differential Protection
Numerical Distance Protection of Transmission Line 245 -,
Mann and Morrison Method
Differential Equation Method
Algorithms and Assumptions
Review Questions
A.l Introduction
A.2 CT Construction
A.3 Measurement CT and Protective CT
A.4 Steady State Ratio and Phase Angle Errors
A.4.1 Current Transformer
A.4.2 Potential Transformer
A.5 Transient Errors in CT
A.6 Transient Errors in CVT
A.7 Saturation of CT
A.8 CT Accuracy Classification
Appendix &POWER SWING
B.l Introduction
B.2 Stable and Unstable Power Swing
B.3 Impedance Seen by Relay During Power Swing
B.4 Out-of-step Blocking Scheme
B.5 Out-of-step Tripping Scheme
Appendix CPROTECTION OF LONGESTAND SHORTEST LINES
C. 1 Introduction
C.2 Longest Line That Can Be Protected
C.3 Shortest Line That Can Be Protected