|Instrument Transformers: Current Transformers – Introduction, Terms and Definitions, Accuracy class, Burden on CT, Vector diagram of CT, Magnetization curve of CT, Open circuited CT secondary, Polarity of CT and connections, Selection of CT for protection ratings, Types & construction, Multi wound CTs, Intermediate CTs, Transient behavior, Application for various protections. Voltage Transformers – Introduction, Theory of VT, Specifications for VT, Terms & definitions, Accuracy classes & uses, Burdens on VT, Connection of VTs, Residually connected VT, Electromagnetic VT, CVT & CVT as coupling capacitor, Transient behavior of CVT, Application of CVT for protective relaying. Substation Equipment:|
Switching Devices:- Isolator & Earthling Switch(Requirements & definitions, Types of construction, Pantograph isolators, Ratings),Contactors(Basic working principle, Terms & definitions, Contactors as starters for motors, Rated characteristics/utilization category of contactors), Circuit Breakers (working principle, Construction, operating mechanisms, Arc initiation, arc quenching principles, ratings & applications of MCB, MCCB, ELCB, air circuit breakers, oil circuit breakers, SF6 circuit breakers, vacuum circuit breakers, Mechanical life, electrical life and testing of circuit br3eakers), Switch Boards, Acquaintance with ISI Standards HRC Fuses & their applications-Introduction, types of devices with fuse, definitions, construction, fuse link of HRC fuse, Action of HRC fuse, shape of fuse element, specification of a fuse link, characteristics of fuse, cut-off, classification & categories, selection of fuse links, fuse for protection of motor, discrimination, fuse for protection of radial lines/meshed feeders, equipment incorporating fuses, high voltage current limiting fuses, expulsion type high voltage fuses, drop out fuse. Introduction to Protective relaying: About protective relaying, Shunt & Series Faults, causes and Effects of faults, Importance of protective relaying, Protective zones, primary & Back-up protection, Back-up protection by time grading principle, desirable qualities of protective relaying, some terms in protective relaying, Distinction between relay unit, protective scheme and Protective system, Actuating quantities, Thermal Relays Electromechanical relays and static relays, Power line carrier channel, programmable relays, system security, role of engineers. Electromagnetic relays – Introduction, basic connections of relay, Auxiliary switch, sealing and auxiliary relays, measurement in relays, Pick up, drop off, Attracted armature & induction disc relays, Thermal, bimetal relays, Frequency relays, under/over voltage relays, DC relays, All or nothing relays. Different Principles of protection – Over current& earth fault (non- directional & directional types) , differential protection, distance protection (Working Principle of Impedance relay, Causes and remedies of Over reach-under reach, Reactance and Mho relay, Power swing blocking relay).Protection schemes provided for major apparatus: Generators – Stator side(Differential , Restricted Earth fault, protection for 100% winding, Negative phase sequence, Reverse power, turn-turn fault), Rotor side (Field suppression, field failure, Earth fault, turn to turn fault) Transformers-Differential protection for star delta Transformer, Harmonic restraint relay, REF protection, Protection provided for incipient faults (Gas actuated relay). Induction motors – Protection of motor against over load, short circuit, earth fault, single phasing, unbalance, locked rotor, phase reversal, under voltage, winding temperature. University of Mumbai Electrical Engineering Rev 2012-13 Protection of Transmission Lines: Feeder protection – Time grading, current grading , combined time & current grading protection provided for Radial, Ring Main, Parallel, T-Feeder. Bus Zone Protection – Differential protection provided for different types of bus zones. LV, MV, HV Transmission Lines – Protection provided by over current, earth fault, Differential and Stepped distance protection. EHV & UHV Transmission lines – Need for auto reclosure schemes, Carrier aided distance protection (Directional comparison method), Power Line Carrier Current protection (Phase comparison method).Introduction to Static & Numerical Relays Advantages and Disadvantages, Revision and application of op-amps, logic gates, DSP, Signal sampling, Relays as comparators (Amplitude & phase), Distance relays as comparators.
|Three Phase Transformers- Construction & Phasor groups: Construction, Three phase transformer connections and phasor groups. Three Phase Transformers- Operation: Parallel operation, Excitation Phenomenon in transformers, Harmonics in three phase transformers, Disadvantages of harmonics in transformers, Suppression of harmonics, Oscillating neutral phenomenon, Switching in transient phenomenon, Open delta or V- connection, Three phase to two phase conversion (Scott connection).Three Phase Induction Motors-Introduction:|
Construction, Principle of operation, Rotor frequency, Rotor emf, Current and Power, Induction motor phasor diagram, Analysis of Equivalent circuit, Torque-speed characteristics in braking, motoring and generating regions, Effect of voltage and frequency variations on Induction motor performance, Losses and efficiency, Power stages, No load and block rotor test, Circle diagram, Applications of 3? IM Three Phase Induction Motors- Speed Control and Starting: Speed control methods including V/f method (excluding Slip power recovery scheme), Starting methods, High torque motors, Cogging and crawling, Basic principle of Induction Generator.
Single phase Induction Motor-Introduction: Principle of operation, Double field revolving theory, Equivalent circuit of single phase induction motor, Determination of equivalent circuit parameters from no load and block rotor test.
Single phase Induction Motor- Starting Methods: Staring methods, Split phase starting- Resistance spilt phase, capacitor split phase, capacitor start and run, shaded pole starting, Reluctance starting. Calculation of capacitor at starting. Applications of 1? IM