SHE Level 4
SCQF Credit Points 20.00
ECTS Credit Points 10.00
Module Code MHH624682
Module Leader Martin MacDonald
School School of Computing, Engineering and Built Environment
Subject SCEBE - School Office
  • A (September start)
  • B (January start)

Summary of Content

The aim of this module is to provide the student with a detailed understanding of the Power Systems Operation and Protection, using switchgears and circuit breakers.


Relays: General considerations, sensing of faults, construction of electro-magnetic attraction and induction types relays, Buchholz and negative sequence relay, concept of reset, pick up, inverse time and definite time characteristics, over current , over voltage, directional, differential and distance relays on R-X diagram. Static Relays: Introduction, advantage and limitation of static relays, static over current, directional, distance and differential relays. Protection Types & detection of faults and their effects, alternator protection scheme (stator, rotor, reverse power protection etc.). Power transformer protection (external and internal faults protection), generator-transformer unit protection scheme, bus bar protection. Transmission line protection (current/time grading, distance), Pilot relaying schemes, power line carrier protection. Circuit Breaker: Theory of current interruption- energy balance and recovery rate theory, arc quenching, recovery and re-striking voltages. Types of circuit breakers. bulk oil and minimum oil, air break and air blast, SulphurHexaFluride (SF6) and vacuum circuit breakers. Rating selection and testing of circuit breakers/operating mechanisms. LT switchgear, HRC fuses, types construction and applications. Modern Trends In Protection: Electronic relays, static relays functional circuits: comparators, level detectors, logic and training circuits, microprocessor and computer based protection schemes, software development for protection, security & reliability

Learning Outcomes

On completion of this module the student should be able to:1. Analyse performance of practical CT with its relay burden for detection of a fault in power system. (AM1)2. Compare Electromechanical, Static and Digital relaying principles for protection of power system components. (AM1, AM5) 3. Design time graded overcurrent protection scheme for protection of feeder using Definite Time Overcurrent Relay and Inverse Time Overcurrent Relay. (AM1, AM3, AM7)4. Design percentage Differential Protection scheme for a three phase Alternator for protection from stator and rotor earth faults. (AM1, AM3, AM7)5. Implement Merz Price protection scheme for protection of Star-Delta and Delta-Delta connected power transformer. (AM1, AM3, AM7)6. Analyse three stepped distance relay characteristic with different impedance and time settings for protection of a feeder. (AM1, AM3, AM7)

Teaching / Learning Strategy

The main teaching method will be based on lectures. The students will be expected to perform directed reading exercises and self-learning exercises on topics related to Power System Protection. Tutorials will be used to reinforce the module material and to discuss the issues raised by the directed reading

Indicative Reading

-360 1. L.G. Hewitson, Mark Brown and Ramakrishanan, " Practical Power System Protection", Elsevier, 2005 2. Paithankar Y. O.," Transmission Network Protection: Theory and Practice", Marcel Deicker, 3 rd Ed., 2004. 3. Badriram&Vishwakarma, " Power System Protection and Switchgear", Tata Mac-Graw Hill, 2001 Sunil S. Rao, " Switchgear and Protection", Khanna Publisher,13 th Ed. 2008

Transferrable Skills

Tutorials provide:Problem Solving and Numeracy Reports provide:Communication/Literacy/Linguistic/Critical Evaluation

Module Structure

Activity Total Hours
Lectures (FT) 56.00
Tutorials (FT) 28.00
Assessment (FT) 16.00
Independent Learning (FT) 100.00

Assessment Methods

Component Duration Weighting Threshold Description
Exam (School) 1.50 20.00 n/a Mid-term test :10% (Unseen written - 1 ½ Hours)
Coursework 1 n/a 30.00 n/a Design Exercise - written report 2000 words
Exam (Exams Office) 3.00 50.00 35% Final Examination: 50% (Unseen written 3 Hours)