5EX5-TRANSMISSION & DISTRIBUTION OF ELECTRICAL POWER |
Units: I |
(i) Supply systems: - Basic network of power system. Transmission and
distribution voltage, effect of system voltage on size of conductor and losses. Comparison of
DC 2- wire, DC 3- wire, 1- phase AC and 3- phase AC (3- wire and 4- wire) systems.
(ii)
Distribution Systems: -
Primary and secondary distribution systems, feeder, distributor and service mains. Radial and
ring- main distribution systems. Kelvin’s law for conductor size.
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Units: II-Mechanical features of overhead lines:- |
Conductor material and types of
conductor. Conductor arrangements and spacing. Calculation of sag and tension, supports at
differentlevels, effect of wind and ice loading, stringing chart and sag template.
Conductor vibrations and vibration dampers. |
Units: III-Parameters of Transmission Lines: |
Resistance inductance and capacitance of
overhead lines, effect of earth, line transposition. Geometric mean radius and distance.
Inductance and capacitance of line with symmetrical and unsymmetrical spacing
Inductance and capacitance of double circuit lines. Skin and proximity effects.
Equivalent circuits and performance of short and medium transmission lines.
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Units: IV |
(i)Generalized ABCD line constants, equivalent circuit and performance of long
transmission line. Ferranti effect. Interference with communication circuits. Power flow
through a transmission line.
(ii) Corona: Electric stress between parallel conductors.
Disruptive critical voltage and visual critical voltage, Factors affecting corona. Corona
power loss. Effects of corona.
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Units: V |
(i) Insulators: Pin, shackle, suspension, post and strain insulators. Voltage
distribution across an insulator string, grading and methods of improving string
efficiency.
(ii) Underground
Cables: Conductor, insulator, sheathing and armoring materials. Types of cables.
Insulator resistance and capacitance calculation. Electrostatic stresses and reduction of
maximum stresses. Causes of breakdown. Thermal rating of cable. Introduction to oil filled
and gas filled cables.
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