Why Overhead Transmission Line Conductors are not insulated?


transmission line not insulated


Hey, today we are going to know why overhead transmission and distribution line conductors are not insulated.

We know that the insulation of an Electrical system depends upon voltage. We know that overhead transmission and distribution lines carrying very high voltage. So, it will be too costly to insulate overhead transmission and distribution lines because as the voltage is more so the thickness of the insulation should be more and a million kilometers of transmission line insulation will be very costly. This the main reason why overhead transmission and distribution lines not insulated.

As the transmission and distribution lines are at a height so there is no chance of any physical contact by humans or anything. So for this reason also overhead lines are not insulated.


The conductor used in overhead transmission and distribution line is called ACSR(Aluminium Conductor Steel Reinforced) which is the combination of aluminum and steel. So this type of conductor has low corrosion effect, loss, etc. So insulation is not required to protect the conductor from corrosion, losses, etc.

Overhead transmission and distribution line has already Sag and it's sag increasing with time so if the transmission line has insulation it will damage when Sag increasing with time.

As the overhead lines are not insulated, the air surrounding them act as insulation. Air provides insulation between two adjacent conductors of an overhead line. Due to air between two adjacent conductors capacitance effect occurs. Capacitance effect occurs between conductor and earth called earth capacitance. The capacitance effect occurs between two line conductor is called line capacitance.


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Why Overhead Transmission Line Conductors are not insulated? Why Overhead Transmission Line Conductors are not insulated? Reviewed by ETechnoG on 2/20/2020 Rating: 5
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