Digital Protection of Power System

By Prof. Bhaveshkumar R. Bhalja   |   IIT Roorkee
Learners enrolled: 1450
This course is to be prepared to serve as an introductory course for Digital Protection of Power System for post graduate students of various technical institutes such as IITs, NITs, state level government colleagues, deemed universities and affiliated colleges to the deemed universities. It aims to give a comprehensive up-to-date presentation of the fundamentals of digital relays, concept of digital signal processing used in digital relays and various algorithms utilized in digital/numerical relays. It begins with a state-of-the-art survey of theories and methods of digital/numeric relays and phasor measurement units (PMUs) along with IEC 61850 substation and automation protocols. In continuation, it provides a theoretical summary along with examples of real-life engineering applications to a variety of technical problems such as load shedding and frequency relaying, reclosing and synchronizing, protection issues due to interconnection of distributed energy resources in the grid and digital protection of various electrical apparatus such as generator, transformer, transmission lines etc. In this point of view, the said course bridges the gap between the theoretical advances, experimental validations and practical engineering in real life.

It covers analytical techniques used in digital relays and application of PMUs in easily comprehensible manners so that academicians and particularly new beginners would not find any difficulty. Further, discussion of various digital relaying schemes for line and equipment protection is one of the unique features of this course. An important part of the course is the sufficient number of examples and problems included in each unit. Some of the problems are dedicatedly difficult for the in-depth knowledge in the topics, however, unrealistic problems are not taken. Aim of this course is to educate the reader and help the student to realize that many of the problems that will be faced in practice will require careful analysis, consideration and some approximations.

INTENDED AUDIENCE: Post graduate students of all IITs, NITs, State Colleges, deemed universities and affiliated colleges.


Course Status : Completed
Course Type : Core
Duration : 8 weeks
Category :
  • Electrical, Electronics and Communications Engineering
  • Power Systems and Power Electronics
Credit Points : 2
Level : Postgraduate
Start Date : 24 Jan 2022
End Date : 18 Mar 2022
Enrollment Ends : 07 Feb 2022
Exam Date : 27 Mar 2022 IST

Note: This exam date is subjected to change based on seat availability. You can check final exam date on your hall ticket.

Page Visits

Course layout

Week 1: Introduction of digital relays; Fundamentals of digital relays; Basic layout and elements of the digital relays with visual illustration; The concept of sampling and aliasing for digital relays; Sliding window concept of digital relays
Week 2: Estimation of phasors using Full-cycle Discrete Fourier Transform (DFT); Estimation of phasors using Half-cycle DFT and introduction of Discrete Cosine Transform; Estimation of phasors using Walsh function technique and Least Error Square technique; Estimation of frequency in digital relays and practical considerations for selection of various algorithms; Digital Differential Protection of Generator, Induction motors and Busbar
Week 3: Digital Differential Protection of Transformers; Digital Directional/Non-directional Overcurrent and Earth fault relays; Overcurrent relay coordination in an interconnected power system network: LINKNET structure and determination of primary/backup relay pairs; Overcurrent relay coordination in an interconnected power system network: Example; Problems faced by digital distance relays.
Week 4: Computation of direction and impedance for digital distance relays; Power swing detection and blocking technique in digital distance Relays; Protection of double-circuit transmission line using digital distance relays; Protection of multi-terminal transmission line using digital distance relays; Protection of series compensated transmission line using digital distance relays: Basic components.
Week 5: Protection of Series compensated transmission line using digital distance relays: Voltage/current inversion and sub-synchronous oscillations and additional transients; Load shedding and Frequency relaying: Various load shedding techniques and frequency relays; Load shedding and Frequency relaying: Factors to be considered and rate of frequency decline; Islanding phenomena: Hazards and risk of islanding and methods of islanding; Loss of existing protection coordination among protective devices: Recloser-Fuse coordination for DG interfaced Distribution network
Week 6: Hardware-in-loop testing of an islanding detection technique; Protection of dc microgrid: Review and challenges; AC microgrid protection: Problems and solutions; Insight in to hybrid ac-dc microgrid protection; Application of travelling wave (TW) and wavelet transform (WT) based algorithm
Week 7: Application of artificial intelligence (AI) in digital relaying; Introduction to Phasor Measurement Unit (PMU); Introduction of IEEE C37.118 standard; Wide area monitoring, control and protection using PMU; Introduction to IEC 61850 standard for substation automation and relay interoperability: Part-1
Week 8: 
Introduction to IEC 61850 standard for substation automation and relay interoperability: Part-2; Introduction to IEC 61850 standard for substation automation and relay interoperability: Part-3; Protection of High voltage dc transmission network; Various cyber-attacks at substation/transmission level for Indian power grid network; Basic concept and application of control switching

Books and references

  •  Anderson, P.M., Power System Protection, IEEE Press, New York, 1999.
  • Blackburn, J.L., Applied Protective Relaying, Westinghouse Electric Corporation, New York, 1982.
  • Bhavesh Bhalja, R. P. Maheshwari, N. G. Chothani, Protection and Switchgear, Oxford University Press, 2nd edition, New Delhi, India, 2018.
  • Oza, B. A., N. C. Nair, R. P. Mehta, et al., Power System Protection & Switchgear, Tata McGraw Hill, New Delhi, 2010.
  • Phadke, A.G. and J.S. Thorp, Computer Relaying for Power Systems, Research Study Press Ltd, John Wiley & Sons, Taunton, UK, 1988.
  • Bhavesh Bhalja and Vijay H. Makwana, ""Transmission Line Protection Using Digital Technology,"" Springer Science+Business Media Singapore Pte. Ltd; Singapore, January 2016.

Instructor bio

Prof. Bhaveshkumar R. Bhalja

IIT Roorkee
"Dr. Bhaveshkumar R. Bhalja is working as a Professor, Department of Electrical Engineering, Indian Institute of Technology (IIT) Roorkee, Roorkee, India. He has a teaching experience of more than 20 years. He has published more than 150 papers in journals at international and national levels. He received Fulbright Nehru Academic and Professional Excellence Fellowships and worked as a visiting scholar at the Department of Electrical and Computer Engineering, Texas A & M University, College Station, Texas, US for a period of 9 months in 2018-19 in the area of “Fault Detection using Synchrophasor”. He has been awarded “Young Engineers Award”, “Certificate of Merit Award” and “Pandit Madan Mohan Malviya Memorial Prize” by Institution of Engineers, India in 2009, 2007 and 2016, respectively. He has been awarded “Hari-ohm Ashram Prerit Inter-University Smarak Trust Award” by Sardar Patel University, Vallabh Vidyanagar, Anand, India in 2009. One of his paper titled “Miscordination of Relay in Radial Distribution Network Containing Distributed Generation” also got Best Poster award at IEEE Conference on Recent Advances in Intelligent Computational Systems, Sep 22-24, 2011, Trivandrum, India. He has written books on Protection and Switchgear, Oxford University Press, New Delhi, India, 2nd Edition, 2018 and Transmission Line Protection Using Digital Technology, Springer Science Business Media Singapore Pte. Ltd; Singapore, January 2016. He has also delivered popular NPTEL course on “Power System Protection and Switchgear” in 2020. Currently, he is also holding a position of Associate Dean of Academic Affairs (Evaluation) of IIT Roorkee. He is involved in many research and development projects of DST, CSIR, CPRI and National High Speed Rail Corporation Limited. He is also associated with auditing and testing of 400 kV and 765 kV sub-stations of India. Further, he is having many consultancy projects related to the development of PMUs based set-up and FPGA controllers. His research interests include Digital Protection & Automation, Smart Grid Technologies and Applications, Distributed Generation, Micro-grid, Power Quality Improvement, Phasor Measurement Unit, Condition Monitoring of Electrical Apparatus and Application of Artificial Intelligence. He has guided more than 50 UG projects, 28 M. Tech. Dissertations 12 doctoral students. He is a Senior Member of IEEE and Fellow of IE and ISTE. He is working as an Associate Editor of IET Generation Transmission and Distribution and Canadian Journal of Electrical and Computer Engineering, IEEE Canada, Canada."

Course certificate

The course is free to enroll and learn from. But if you want a certificate, you have to register and write the proctored exam conducted by us in person at any of the designated exam centres.
The exam is optional for a fee of Rs 1000/- (Rupees one thousand only).
Date and Time of Exams: 27 March 2022 Morning session 9am to 12 noon; Afternoon Session 2pm to 5pm.
Registration url: Announcements will be made when the registration form is open for registrations.
The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published. If there are any changes, it will be mentioned then.
Please check the form for more details on the cities where the exams will be held, the conditions you agree to when you fill the form etc.


Average assignment score = 25% of average of best 6 assignments out of the total 8 assignments given in the course.
Exam score = 75% of the proctored certification exam score out of 100

Final score = Average assignment score + Exam score

YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.

Certificate will have your name, photograph and the score in the final exam with the breakup. It will have the logos of NPTEL and IIT Roorkee. It will be e-verifiable at nptel.ac.in/noc.

Only the e-certificate will be made available. Hard copies will not be dispatched.

Once again, thanks for your interest in our online courses and certification. Happy learning.

- NPTEL team

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