30.
Switchgear and Protective CREDIT & CONTACT HOURS: KNOWLEDGE AREA/DOMAIN
Devices Technology COURSE (2+1) Depth Elective-III
CODE & TITLE 32 Theory + 16 Lab sessions
(ELT-321)
Switchgear and Protective Devices
Technology
After completion of this course Taxonomy (Level) PLO
students will be able to:
CLO-1 Apply the basic knowledge C-3 PLO-1
of protection system
attributes and understand
the concepts of various
protection schemes.
CLO-2 Solve and evaluate the C-5 PLO-2
protection schemes for a
power system
CLO-3 Operate equipment and P-4 PLO-5
practice the design the
characteristics of various
protection schemes
CLO-4 Construct the behavior of C-6 PLO-5
various protection systems
and ensure protection
coordination on simulation
software (like ETAP)
Course Outline for Theory
Protective Relays: Need for protective relaying in power systems, basic attributes of protective relaying, principles
and characteristics of protective relaying, theory and classification of relays, Instrument Transformers, CT burden
and accuracy classes. Overcurrent Protection: Inverse characteristics of overcurrent relays (OCR), inverse definite
minimum time (IDMT) relays, primary and backup protection, relay coordination, application of IDMT relays, definite
time overcurrent (DTOC) relays, application of DTOC relays, protection of a three-phase feeder. Differential
Protection: Dot convention and CT placement, Simple Differential Protection, Zone of Protection of the Differential
Relay, Percentage Differential Relay, Earth Leakage Protection.
Protection of Transformers: Transformer faults, differential Protection of a three-winding transformer, Inrush
current and differential protection, Bucholz relays, Over-fluxing in a transformer. Protection of Generators: Faults in
stator and rotor windings, Protective devices for stator, rotor, and prime mover of a generator, Abnormal operating
conditions (unbalanced loading, over-speeding, loss of excitation and loss of prime mover) and their protection.
Protection of Motor: Fuse protection motor, Single phasing protection, Protective devices for stator, rotor faults.
Protection of Transmission Lines: Drawbacks of overcurrent protection, Distance protection, Zones of protection.
Fuses and Circuit Breakers: Fuses Introduction, HRC/HBC fuse as the best protection against short circuits, principle
and current-limiting phenomenon in HRC/HBC fuses, Principle of circuit interruption in circuit breakers, Circuit
Breaker-Types and characteristics, Ratings of HRC/HBC fuses and circuit breakers.
Lab Outline
Protective Relays Overcurrent Protection. Differential Protection. Protection of Transformers. Protection of
Generators and Transmission Lines. HRC/HBC Fuses and Circuit Breakers
Recommended Books
1. Fundamentals of Power System Protection by Y.G. Paithankar and S.R. Bhide (Latest edition)
2. Protective Relaying; Principles and Applications, by J. Lewis Blackburn, Thomas J. Domin. (Latest edition)
