- the weight of the line is more with aluminium
- the volume of the conductor is more with aluminium
- number of towers required in aluminium will be more
- All of these
Answer: 4. All of these
Explanation:
- The conductivity of aluminium is 60% that of copper. The smaller conductivity of aluminum means that for any particular transmission efficiency, the X-sectional area of the conductor must be larger in aluminium than in copper.
- For the same resistance, the diameter of the aluminium conductor is about 1·26 times the diameter of the copper conductor.
- The specific gravity of aluminium (2·71 gm/cc) is lower than that of copper (8·9 gm/cc). Therefore, an aluminium conductor has almost one-half the weight of an equivalent copper conductor.
- Aluminium conductor being light is liable to greater swings, and hence larger cross-arms are required.
- Due to the lower tensile strength and higher coefficient of linear expansion of aluminium, the sag is greater in aluminium conductors.
Considering the combined properties of cost, condAuctivity, tensile strength, weight, etc., aluminum has an edge over copper. Therefore, it is widely used as a conductor material.
It is particularly profitable to use aluminium for heavy-current transmission where the conductor size is large, and its cost forms a major proportion of the total cost of the complete installation.
