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.PRE-REQUISITE: Nil.INDUSRTY SUPPORT: L&T, ABB, Siemens, SEL, etc.
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 relaysWeek 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 BusbarWeek 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 networkWeek 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