Contents

• 1. Static Relays and Static over Current Relays

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  Objectives, Introduction to Switchgear & Protection, Introduction to Static Relays, Block Discription of Static Relay, Merits of Static Relays, Demerits of Static Relays, Comparators, General Equation of Comparators, Analysis of Amplitude Comparator, Analysis of Phase Comparator, Duality between Amplitude and Phase Comparator, Amplitude Comparators, Functions of Amplitude Comparators, Integrating Comparators (Circulating Current Type), Instantaneous Comparators (Phase Splitting Type), Sampling Comparator, Phase Comparators, Vector Product Type, Coincidence Type Phase Comparator, Static Overcurrent Relays, Time Characteristic of Overcurrent Relay, Static Instantaneous Overcurrent Relay, Static Definite Time Overcurrent Relay, Static Inverse-time Overcurrent Relay, Static Directional Overcurrent Relay, Review Questions.
   
  2. Static Differential Relays and Distance Relays

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  Objectives, Introduction to Differential Relays, Analysis of Electromagnetic Relay, Analysis of Static Differential Relay, Block Description of Static Differential Relay, Static Differential Relay Scheme, Introduction to Static Differential Protection, Static Differential Protection of Generator, Static Differential Protection of Transformer, Differential Protection of Two-winding Transformer, Differential Protection of Three Winding Transformer, Protection of Transformers using Harmonic Restraint Percentage Differential Relays, Protection Against Magnetising Inrush Current, Protection Against Saturation of Current Transformer Magnetic Circuit, Static Distance Relays, Static Impedance Relay, Operating Principle of an Impedance Relay, Characteristics of Impedance Relay, Realisation of Static Impedance Relay using an Amplitude Comparator, Realisation of Static Impedance Relay using a Phase Comparator, Static Reactance Relay, Operating Principle of Reactance Relay, Characteristics of Reactance Relay, Realisation of Static Reactance Relay using an Amplitude Comparator, Realisation of Static Reactance Relay using a Phase Comparator, Static MHO Relays, Operating Principle of MHO Relay, Characteristics of MHO Relay, Realisation of Static MHO Relay using an Amplitude Comparator, Realisation of Static MHO Relay using a Phase Comparator, Review Questions.
   
  3. Carrier Current Protection and Distance Protection

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  Objectives, Introduction to Carrier Current Protection, Basic Apparatus and Scheme of Power Line Carrier System, Methods of Carrier Current Protection, Principle of Operation of Directional Comparison Method, Priciple of Operation of Phase Comparison Method, Carrier Assisted distance Protection, Carrier Transfer or Intertripping Scheme, Carrier Acceleration Scheme, Carrier Blocking Scheme, Distance Protection, Effect of Power Swings on the Performance of Distance Protection, Stable and Unstable Power Swing, Power Swing (Power Surge) Analysis, Out of Step Tripping and Blocking Relays, Out of Step Relaying, Principle of Out-of-step Tripping Relay, Principle of Out-of-step Blocking Relay, MHO Relay with Blinders, Introduction to Quadrilateral Relay, Relisation of Quadrilateral Characteristic, Introduction to Elliptical Relay, Realisation of Elliptical Relay, Review Questions.
   
  4. Circuit Breakers I

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  Objectives, Introduction, Electric Arc, Electric Arc Characteristic, Volt Ampere Characteristics, Arc Interruption, High Resistance Interruption, Low Resistance or Current Zero Interruption, Arc Interruption Theories, Recovery Rate Theory (Slepian’s Theory), Energy Balance Theory, Restriking Voltage, Classification of Restriking Transients, Recovery Voltage, Effect of Different Parameters on Transient Recovery Voltage (TRV), Effect of Natural Frequency on TRV, Effect of Power Factor on TRV, Effect of Reactance Drop on Recovery Voltage, Effect of Armature Reaction on Recovery Voltage, Rate of Rise of Restriking Voltage (RRRV), Expression for Restriking Voltage and RRRV, Resistance Switching, Current Chopping, Interruption of Capacitive Current, Oil Circuit Breaker, Bulk Oil Circuit Breaker (BOCBs), Minimum Oil Circuit Breaker (MOCBs), Air Circuit Breaker (ACB), Review Questions.
   
  5. Circuit Breaker II and Digital Protection

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  Objectives, Air Blast Circuit Breaker (ABCB), Construction of Air blast Circuit Breaker, Working of ABCB, Types of ABCB, Sulphur Hexafluoride (SF6) Circuit Breaker, Properties of SF6 Gas, Construction of SF6 Circuit Breaker, Working of SF6 Circuit Breaker, Types of SF6 Circuit Breakers, Vacuum Circuit Breaker, Construction, Working, Current Chopping, Vacuum Arc-recovery Phenomenon, Selection of Circuit Breakers, Rating of Circuit Breakers, Digital Protection: Introduction to Digital Protection, Brief Description of Block Diagram of Digital Relay, Introduction to Digital Overcurrent Relay, Transformer Differential Protection, Digital Protection of Transformer, Walsh Transformer Based Filter, Basic Theory of Relay in Digital Protection of Transformer, Transmission Line Distance Protection, Software Design, Hardware Design, Review Questions.
   
  P. Paper