Aptransco Sub Engineer Electrical Syllabus 2012
The main topics are as follows with detailed content below ::
- ELECTRICAL MACHINES
- POWER GENERATION AND SWITCHGEAR AND PROTECTION
- TRANSMISSION AND DISTRIBUTION
- MEASURING INSTRUMENTS AND ELECTRIC CIRCUITS
- UTILIZATION OF ELECTRICAL ENERGY
- D.C. GENERATORS And MOTORS: Expression for emf equation of D.C.Generaor, armature windings, armature reaction, types of generators, characteristics. Torque equation of D.C.Motor, characteristics, speed control, starters, losses and efficiency. Testing of D.C. Machines.
- TRANSFORMERS: emf equation of single phase transformer, operation of transformer on load, equivalent circuit, vector diagram, open-circuit and short-circuit tests, voltage regulation, losses and efficiency, all-day efficiency, parallel operation of single-phase transformers with equal voltage ratios. Voltage and current relations for three-phase transformer connections. Principle of operation of auto-transformer. Cooling of power transformer, Operation of Buchhloz’s relay.
- ALTERNATION AND SYNCHRONOUS MOTORS: Salient-pole and cylindrical rotor types of construction. Alternator EMF equation and windings, armature reaction, voltage regulation using synchronous impedance, open-circuit and short-circuit tests, voltage variation against load currents at different power factors, parallel operation of alternators; synchronization by lamps method and synchroscope. Synchronous motors: Starting methods, effect of change of excitation at constant load, V-curves, Hunting, synchronous condensor.
- THREE-PHASE INDUCTION MOTORS: Constructional aspects of cage and wound rotor types of induction motors, expression for torque, torque-ship characteristics, full load torque, starting torque and maximum torque, effects of variation of rotor resistance; losses and efficiency; different starting methods; speed control methods.
- SINGLE-PHASE INDUCTION MOTORS AND COMMUTATOR MOTORS: Constructional features and operation of single-phase induction motors: split phase,capacitor and shaded pole types. Principle of operation of A.C. series motor, universal motor, Schrage motor.
II. POWER GENERATION AND SWITCHGEAR AND PROTECTION:
- HYDRO-POWER PLANTS: Functions of different components of Hydel stations,water power equation, surge tank, choice of turbines, storage and pondage; base load and peak load operation, pumped storage plant.
- THERMAL POWER PLANTS: Plant line diagram and functions of different components of coal-fired steam power plant; boilers, steam turbines, condensers, superheater, economizer, cooling towers, chimney.
- NUCLEAR PLANT: Schematic arrangement and functions of different components in nuclear power reactor.
- COMBINED OPERATION OF POWER PLANTS AND ECONOMIC ASPECTS: Advantage of combined operation of Hydel and Thermal power plants; Load and Load duration curves, load factor, diversity factor and demand factor, capacity factor; types of tariffs, factors influencing tariff design.
- FAULTS AND SWITCHING APPARATUS: Short-circuit calculations; fuses and isolators; circuit breakers: theory of arc interruption and different types of oil circuit breakers; lightning arresters and their selection and location.
- PROTECTIVE RELAYING: Basic requirements of protective relaying, primary and back-up protection; classification of electromagnetic relays and their principles of operation; time current characteristic curves; induction type over-current relay, distance relays; Merz price protection, differential protection of transformers, bus bar protection.
III. TRANSMISSION AND DISTRIBUTION:
- LINE CONDUCTORS, LINE SUPPORTS AND SAG CALCULATIONS: Different types of line conductors, conductor sizes commonly used for different voltagelevels, Types of line supports, factors influencing the selection, cross-arms; spans, conductor spacings and ground clearances. Sag calculations and stringing charts.
- TRANSMISSION LINE PARAMETERS: Determination of inductance and capacitance of round and parallel conductors in single phase and three-phase symmetrically spaced lines.
- PERFORMANCE OF LINES: Choice of voltage; short, medium and long lines; calculation of sending-end voltage, regulation and efficiency for short lines; nominal ∏ and nominal-T methods; Ferranti effect; corona: critical voltages and factors affecting corona.
- INSULATORS AND SUBSTATIONS: Different types of insulators: Pin type, strain type, suspension type and relative merits; voltage distribution across string of suspension insulators, string efficiency and methods of improving arcing horns. Equipment used in substations, bus-bar arrangements.
- CABLE AND DISTRIBUTION SYSTEMS: Comparison between overhead lines and under ground cable. Types of cables, insulation resistance; localization of cable faults. Primary and secondary distribution; Feeders and service mains; radial and ring systems of distribution; singlephase a.c. distribution.
IV. MEASURING INSTRUMENTS AND ELECTRIC CIRCUITS:
- MEASURING INSTRUMENTS: Indicating instruments: deflecting, controlling and damping torques, pointers and scales; ammeters and voltmeters: moving coil, moving iron, dynamometer, induction types; instrument transformers: C.T and P.T., Wattmeters and measurement of power in three phase systems by two-wattmeter method; measurement of energy: Energy meters; M.D. indicators; trivector meter.
- ELECTRIC CIRCUITS: Fundamentals of alternating current quantities, sinusoidal waveform; average and effective values; J-notation for A.C quantities; polar form; single phase series and parallel circuits; impedance triangle, phase, power factor, active and reactive components of power; series and parallel resonance. Three-phase star and delta balanced systems.
V. UTILIZATION OF ELECTRICAL ENERGY:
- ELECTRIC DRIVES: Factors governing selection of motors; matching of motors with given loads; electric braking; rating of motor; types of enclosures; motors for particular drive.
- ILLUMINATION: Definitions of commonly used terms and units; types of lamps; requirement of good lighting; laws of illumination; terms like : depreciation factor, utilization factor, waste light factor, luminous efficiency, specific energy consumption, space height ratio.
- ELECTRIC HEATING AND WELDING: Requirements of good heating materials, materials generally employed, resistance heating; electric furnace; induction heating; dielectric heating welding generator and transformers.