Course Details
Subject {L-T-P / C} : EE4101 : Power System Protection { 3-0-0 / 3}
Subject Nature : Theory
Coordinator : Prof. Ananyo Sengupta
Syllabus
Module 1: Over view of Power System Protection: General architecture of protection system, Evolution of relays, Attributes of a protection system, Current and potential transformer for relays, Zones of protections, Concept of primary and back-up protection.
(Hours: 3)
Module 2: Overcurrent Protection: Construction, Operating Principle and Characteristics of Instantaneous overcurrent relay, Definite Time overcurrent relay, Inverse Time overcurrent relay, Inverse definite minimum time overcurrent relay Co-ordination of overcurrent relays for radial lines, Overcurrent protection of three-phase feeder Construction, Operating Principle and Characteristics of Directional overcurrent relay, Directional overcurrent protection of a three-phase feeders Drawbacks of over current protection. (Hours: 7)
Module 3: Distance Protection: Universal Torque Equation, Construction, Operating Principle and Characteristics of Simple Impedance relay, Reactance relay, and Mho relay, performance of different impedance relays during normal loading condition, power swing and effect of arc resistance, Directional properties of various impedance relays, Impact of infeed effect Distance protection of a three-phase line, Three-stepped distance protection. (Hours: 6)
Module 4: Differential Protection: Dot convention, Simple differential protection–behavior during normal load, external fault and internal fault Actual behavior of a simple differential protection scheme and Percentage Differential relay. (Hours: 3)
Module 5: Busbar Protection: Differential protection of busbars, actual behavior of a protective current transformer – effect of CT saturation, High Impedance busbar protection. (Hours: 2)
Module 6: Transformer Protection: Over-current protection, Percentage differential protection of transformer, Inrush phenomenon, percentage differential relay with harmonic restraint, High resistance ground fault protection of a Y-? transformer, Inter-turn faults in transformer, Buchholz relay Protection against over-fluxing. (Hours: 5)
Module 7: Digital Relay: Architecture of a digital relay, Phasor Measurement technique, Numerical distance protection of transmission line, Elimination of decaying dc component, Distance protection by differential protection method, protection of transformer. (Hours: 5)
Module 8: Circuit Breaker: Requirement of circuit breakers, Characteristics of electric arc, Principle of A.C. and D.C. arc interruption, recovery and Restriking voltage and effect of current asymmetry upon them, Interruption of capacitive currents Various types of circuit breakers - Air-breaker circuit breaker, bulk-oil circuit breaker and minimum oil circuit breaker, Air-blast circuit breaker, SF_6 circuit breaker, Vacuum circuit breaker. (Hours: 5)
Course Objectives
- 1. To understand the construction, working principle and application of electromechanical overcurrent protection. <br />2. To understand the basics of distance protection and its application. <br />3. To understand the logic behind differential protection and its application for transformers and bus bars protection. <br />4. To understand the need of digital relaying, its basic components and principles. <br />5. To understand the arc quenching mechanism in circuit breakers
Course Outcomes
At the completion of the course, students will be able to <br />1. Design overcurrent protection for different elements of power system. <br />2. Implement different distance protection scheme for transmission line. <br />3. Design protection measure to entire power system with coordination among the relays placed at different location. <br />4. Design differential protection for transformer and Busbar. <br />5. Compare and design the electromagnetic and digital relays <br />6. Analyse the quenching mechanisms used in air, oil, vacuum and SF6 circuit breakers
Essential Reading
- Y. G. Paithankar and S. R. Bhinde, Fundamentals of Power System Protection, PHI
- Stanley H. Horowitz, Arun G. Phadke, James K. Niemira, Power System Relaying, Willey
Supplementary Reading
- J. L. Blackburn and T. J. Domin, Protecive Relaying: Priciples & Applications, CRC Press
- S. S. Rao, Switch Gear and Protection, Khanna Publishers