8EE3 SWITCHGEAR & PROTECTION

Unit-1 (i) Static Relays: Introduction to static relays, merits and demerits. Comparators: amplitude and phase comparators, duality between amplitude and phase comparators. Introduction to (a) amplitude comparators-circulating current type, phase splitting type and sampling type, (b) phase comparators-vector product type and coincidence type. (ii) Static over Current Relays: Introduction to instantaneous, definite time, inverse time and directional overcurrent relays.
Unit-2 (i) Static Differential Relays: Brief description of static differential relay schemes-single phase and three phase schemes. Introduction to static differential protection of generator and transformer. (ii) Static Distance Relays: Introduction to static impedance, reactance and mho relays.
Unit-3 (i) Carrier Current Protection: Basic apparatus and scheme of power line carrier system. Principle of operation of directional comparison and phase comparison carrier protection and carrier assisted distance protection. (ii) Distance Protection: Effect of power swings on the performance of distance protection. Out of step tripping and blocking relays, mho relay with blinders. Introduction to quadrilateral and elliptical relays.
Unit-4 Circuit Breakers I: Electric arc and its characteristics, arc interruption-high resistance interruption and current zero interruption. Arc interruption theories–recovery rate theory and energy balance theory. Restriking voltage and recovery voltage, develop expressions for restriking voltage and RRRV. Resistance switching, current chopping and interruption of capacitive current. Oil circuit breakers-bulk oil and minimum oil circuit breakers. Air circuit breakers.
Unit-5 (i) Circuit Breakers II: Air blast, SF6 and vacuum circuit breakers. Selection of circuit breakers, rating of circuit breakers. (ii) Digital Protection: Introduction to digital protection. Brief description of block diagram of digital relay. Introduction to digital overcurrent, transformer differential and transmission line distance protection.

Reference/Suggested Books
1. S. S. Rao, “Switchgear and Protection”, Khanna Publishers.
2. B. Ravindranath and M. Chander, Power system Protection and Switchgear, Wiley.
3. B. Ram and D. N. Vishwakarma, “Power System Protection and Switchgear”, TMH.
4. Y. G. Paithankar and S R Bhide, “Fundamentals of Power System Protection”, PHI.
5. T.S.M Rao,“Power System Protection: Static Relays with Microprocessor Applications” Tata Macgraw Hill”.
6. A.R. Van C. Warringtaon, “Protective Relays- Their Theory and Practice, Vol. I & II” Jhon Willey & Sons.