Download Power System Protection

EE121 Power System Protection
L-T-P-Cr: 3 - 1 -0-4
Objective:
the power system and their impact on power system.
understand the characteristics and functions of different relays and their role for power system
protection.
interruption by various switchgears.
Prerequisite:

Symmetrical components and fault calculations
Outcome: Student will be able to understand working and application of different type of relay, Circuit
breaker and different types of protection scheme
Syllabus:
Unit 1. Introduction:Need for protective systems, Nature and causes of faults, Types of faults, Effects of
faults, Relay terminology – definitions – and essential qualities of protection, Classification of protective
relays, Components of protection system, Classification of Protective Scheme, CTs and PTs and their
applications in protection schemes. 4 Lecture
Unit 2. Relay Construction and Operating Principles 3 Lecture Electromechanical relays: Attracted
armature relays, Induction relays and Thermal relays.
Unit 3. Different Protection Schemes 2+3+2+4=11 Lecture
Over current protection: Directional and Non-directional.
Distance protection: Principle, Impedance, Reactance, MHO, Quadrilateral relays.
Differential relays: Simple differential protection, Percentage or Biased differential protection.
Introduction to Static and Numerical relays.
Unit 4. Transformer and Bus-Zone Protection: Types of faults on transformers, Percentage differential
protection, Causes of false differential currents, Three-phase transformer protection and Differential
current protection of bus-zone. 4 Lecture
Unit 5. Rotating Machinery Protection: Stator protection (Percentage differential protection, Protection
against stator inter-turn faults, stator overheating protection), Rotor protection (Field ground protection,
Loss of excitation, Protection against rotor overheating) 4 Lecture
Unit 6. Feeder protection: Over current, differential and distance protection of feeders. Choice between
impedance, reactance and MHO relays. Elementary idea about carrier-aided and Pilot wire protection of
transmission lines. 6 Lecture
Unit 7. Circuit Breaker- Theory of Circuit Interruption: Physics of arc phenomena and arc interruption,
Restriking voltage, Recovery voltage, RRRV, Resistance switching, Current chopping, Interruption of
capacitive current, 4 Hours
Circuit Breakers: Operating Principles and constructional details of different types of circuit breakers – air
break, air blast, oil, SF6 and vacuum circuit breakers, comparative merits of different circuit breakers. 6
Hours
Suggested Readings:
1. Paul M Anderson, Power System Protection, Wiely
2. Badri Ram and D N Vishwakarma, Power System Protection and Switchgear, 2 nd edition, Tata
McGraw Hill Education Pvt. Ltd., New Delhi.
3. B. Bhalja, R. P. Maheshwari and N. G. Chothani, Protection and Switchgear, Oxford University Press,
New Delhi.
4. Stanley H. Horowitz and Arun G. Phadke, Power System Relaying, 3rd edition, John Wiley and Sons,
Ltd.
5. by Y. G. Paithankar and S. R. Bhide, Fundamentals of Power System Protection, Prentice-Hall of
lndiaPvt. Ltd, New Delhi.
6. by B. A. Oza, N. K. Nair, R. P. Mehta and V. H. Makwana, Power System Protection and Switchgear,
Tata McGraw Hill Education Pvt. Ltd., New Delhi.
7. Sunil S. Rao, Switchgear Protection and Power Systems, 12th edition, Khanna
Publishers, New Delhi.