That is depends on the factor of sag and clearance required. And also on the level of voltage transmission used.
ACSR stands for aluminum conductor, steel reinforced. This type of conductor is used for transmission lines that are strung between poles or towers. The aluminum is used for its lower resistance, and the steel provides the structural strength.
To 'damp' vibrations in the conductors.
it will be implemented soon...planning is in progress
DC transmission lines are only used in special applications for example very long distances or for connecting two non-synchronous power systems. As an example UK and France are connected by DC power cables because the two power systems are not synchronised.
Transmission lines are three-phase systems. There are three line conductors in a three-phase system. However, to reduce electric stress at higher voltages, these lines are frequently made up of 'bundled' conductors -so each line might have two, three, or four separate conductors. In addition, transmission towers usually carry separate circuits -i.e. separate three-phase circuits on opposite sides of each tower. So, in the UK for example, a typical 400-kV transmission line will consist of two, separate, three-phase circuits suspended on each side of each tower, with each line consisting of four bundled conductors. That's 24 conductors.
The major material used in the construction of transmission lines is aluminum alloy. Steel is also used to reinforce the lines. No insulation is used for overhead transmission lines.
Answer youtubeAnswerThere are two categories of 'power lines': 'transmission lines' and 'distribution lines'. Transmission lines comprise lines supported by transmission towers ('pylons') and distribution lines comprise lines supported by poles. In both cases, their function is to transport electrical energy from the generating stations to the consumer. Transmission lines are normally part of the grid system, a network which links many generating stations and load centres (usually located near large towns, for example); distribution lines link these load centres to consumers -factories, commercial buildings, residences.
Transmission towers are usually made of steel to help support over the head power lines. They are used in high voltage AC and DC systems and can come in different shapes and sizes.
mho rerlay is used in long transmission lines
Transmission lines are thicker than TV cable wires because the transmission lines are used to transmit both low freq and high freq signals. And the losses of the transmission lines depend the resistance of the line which inturn depend upon length and area. As we have to transmitt the signals over long distances the transmission lines are thicker in size.Whereas in TV cable wires the construction is totally different in which transmission of signals is in between two conductors thereby avoiding losses.Therefore there is no necessity for these lines to be made thicker. That is why transmission lines are thicker than TV cable wires.
ACSR stands for aluminum conductor, steel reinforced. This type of conductor is used for transmission lines that are strung between poles or towers. The aluminum is used for its lower resistance, and the steel provides the structural strength.
There are approximately 220,000 transmission towers in the United States that are used to carry electricity across long distances from power plants to substations and eventually to homes and businesses.
Transmission towers are usually paired or grouped and used to convey high-tension power lines over distances. Do not confuse with antennas used for radio or TV transmissions. a telecommunications tower is used for broadcast purposes -radio or tv or both. neither type of tower is necessarily manned- power- transmission towers are normally unattended and high up. There you have it. good to see an interest in civil engineering structures- things are looking up!
The topmost conductor in a transmission line is called the guard conductor; it is an earthed (grounded) conductor that links the metal support towers. Its function is to protect the transmission lines against lightning strikes. The coloured balls that are sometimes seen distributed along the guard conductor are intended to make the lines easier to see in those areas where aeroplanes might be flying -they are often seen on lines in the vicinity of airfields. They are also used in areas, such as nature reserves, to make the lines visible to large birds.
connection of the ground of all the transmission lines and used as a communication cable between protection devices
It depends upon the voltage; the higher the voltage, the taller the tower and the wider the right-of-way. A tower carrying 500,000-volt lines could be around 150' tall but it also depends on the terrain. The conductors have to be a certain distance from the nearest object, so power lines running across flat, open terrain can be on towers that are shorter than those used for lines running through the mountains, for example.
To 'damp' vibrations in the conductors.