Overhead Power Line:

Since most of the insulation is provided by air, overhead power lines area unit typically the lowest-cost methodology of transmission for big quantities of electrical power. Towers for support of the lines area unit manufactured from wood (as-grown or laminated), steel (either lattice structures or cannular poles), concrete, aluminum, and sometimes strengthened plastics. The bar wire conductors on the road area unit typically manufactured from aluminum (either plain or strengthened with steel or typically composite materials), tho’ some copper wires area unit employed in medium-voltage distribution and low-tension connections to client premises.

The invention of the Strain stuff was a vital consider permitting higher voltages to be used. At the top of the nineteenth century, the restricted electrical strength of Telegraph-style Pin insulators restricted the voltage to no quite sixty-nine, Volts.


Towers for support of the lines ar product of wood (as-grown or laminated), steel or metal (either lattice structures or cannular poles), concrete, and infrequently strengthened plastics.

The vacant wire conductors on the road are usually a product of metal (either plain or strengthened with steel or composite materials like carbon and glass fiber), although some copper wires are employed in medium-voltage distribution and low-tension connections to client premises. a serious goal of overhead transmission line style is to take care of adequate clearance between energized conductors and also the ground therefore on forestall dangerous contact with the road and to produce reliable support for the conductors, resilience to storms, ice loads, earthquakes and different potential harm causes.

Performance of Transmission Lines:

The performance of a cable depends upon the voltage and current relations. These relations are flip are influenced by line parameters, viz., resistance, inductance, and shunt-connected capacitance and its run electrical phenomenon. Generally, the causing finish values are given; and it’s desired to see the receiving finish values. Voltage regulation and potency of transmission are necessary for evaluating the performance of a cable.

In overhead transmission lines, conductors are suspended from the transmission tower with the support of insulators. within the preceding chapters, the impact of alternating currents flowing in transmission lines has been mentioned. whereas the alternating flux linkages end in inductance, the impact of charging force field is sculpturesque as capacitance. The inherent opposition to the flow of electrons is enclosed in conductor resistance. These 3 are the parameters for a cable.

Power System Modeling:

Overhead transmission lines allow the transfer of energy from generating units to the distribution system that serves the top users. Transmission lines additionally interconnect neighboring utilities to allow the economic dispatch of power among regions throughout traditional in operation conditions, furthermore because of the transfer of power between regions throughout emergencies.

Transmission-line voltage levels are higher than sixty potential unit area unit standardized at sixty-nine potential unit, 115 kV, 138 kV, 161 kV, 230 kV, 345 kV, 500 kV, and 745 kV. Transmission voltages higher than 230 potential unit area unit said as extra-high voltage (EHV). High-voltage transmission lines area unit terminated at substations.

There area unit 3 varieties of substations: high-voltage substations, receiving substations, and first substations. At the first substations, the voltage is stepped down through an electrical device to a price appropriate for finish users. as an example, giant industrial customers could also be served directly from the gear.

Design of Overhead Transmission Line: