Switchgear and Protection (EE422)


B.Tech (E&E)




Programme Specific Electives (PSE)

Credits (L-T-P): 

04 (3-1-0)


Fuses and  switches,  methods of earthing,  Circuit Breakers: Arcs, Interruption, RRRV, Current chopping, Interruption of capacitive current, Resistance switching. Types of circuit breakers, Circuit breaker ratings, Auto reclosure. Protective relaying: Functions, Standard definitions and terminology, Fundamental characteristics. Relay classifications, Electromechanical relays. Directional relay, Reverse power relay. Differential protection schemes for bus-bars, transformers and alternators. Frame leakage, bus-bar and transformer protection. Buchholtz relay, Backup protection.  Alternator protection: Negative phase sequence relay, Loss of field protection. Line protection: Overcurrent relays and  schemes,  Distance relays and schemes, Effect of arc resistance, Translay relaying, Carrier current relaying. Induction motor protection: Abnormal operating conditions, Undervoltage,  Phase and earth fault, Overload and unbalance voltage protection.  Solid state relays: Comparators,  Duality between phase and amplitude comparators. General equation of comparators, Realization of directional, Ohm, reactance, impedance and Mho characteristics using the general characteristic equation,  Static distance relays. Computer aided relaying: Introduction to microcomputer based relays,  General functional diagram of microcomputer-based relays.


1. Ravindranath, Chander , Power System Protection and Switchgear, Wiley Eastern, 1994.
2. C. L. Wadhwa, Electrical Power Systems, 2nd Edition, PHI, 1993.
3. Arun G. Phadke, S H Horowitz, Power System Relaying, 2nd Edition, John Wiley, 1995.
4. Badriram, D. N. Vishwakarma, Power System Protection and Switchgear, TMH, 1995.


Electrical and Electronics Engineering

Contact us

Venkatesa Perumal
Associate Professor and Head of the Department
Department of Electrical and Electronics Engineering
National Institute of Technology Karnataka, Surathkal
Srinivasnagar, Surathkal, Mangalore-575025. Karnataka, India.
Ph : +91-824-2473045
Fax: +91-824-2474039
E-mail: hodee[AT]nitk[DOT]ac[DOT]in

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