An overview of Aluminum with Perspective of Transmission Lines
The modern-day transmission line conductors are steel cored aluminum conductors that are abbreviated as ACSR. Given below is an overview of aluminum as material.
Aluminum is cheap and light material as compared to copper however it has much smaller conductivity and tensile strength.
Conductivity: As compared to copper, the conductivity of Aluminum is 60%.
The smaller conductivity of Aluminum implies that for any particular transmission efficiency, the cross-sectional area of conductor must be larger in Aluminum as compared to that of copper.
Diameter of Aluminum conductor: The diameter of Aluminum conductor is around 1·26 times the diameter of copper conductor.
As a result of this the aluminum when used as conductor is exposed to greater wind pressure and, hence supporting towers must be designed for greater transverse strength in case of aluminum.
Because of this higher transmission line towers and pylons with consequence of greater sag are required
Weight of Aluminum conductor
In terms of weight an Aluminum conductor has almost one-half the weight of equivalent copper conductor. Because of this, the supporting structures for Aluminum need not be made so strong as that of copper conductor. Because of light weight, the aluminum conductor is exposed to greater swings and henceforth larger cross-arms are required.
While integrating the combined properties of cost, conductivity, tensile strength, weight etc., Aluminum has an edge over copper.
As a result of this, aluminum is being widely used as a conductor material.