Why Isn't copper used for High Voltage Conductor ?

Copper isn't widely used for high-voltage transmission lines for several key reasons:

Cost: Copper is significantly more expensive than aluminum, which is the most commonly used material for high-voltage lines. Since transmission lines cover vast distances, the cost difference between copper and aluminum adds up considerably, making copper much less economical.

Weight: Copper is denser and heavier than aluminum. Heavier wires require stronger (and therefore more costly) support structures to hold them up, which can make the overall infrastructure more expensive to build and maintain.

Corrosion Resistance: While both copper and aluminum can corrode, aluminum forms a protective oxide layer when exposed to air, which helps prevent further corrosion. This makes aluminum more durable in outdoor and harsh weather conditions, which is essential for transmission lines.

Electrical Conductivity and Efficiency: Although copper has better conductivity than aluminum (allowing it to carry more current with less resistance), aluminum is still efficient enough for transmission purposes, especially given its other benefits. By increasing the diameter of aluminum conductors slightly, they can reach the required conductivity levels for high-voltage lines, offsetting copper's advantage.

Availability: Aluminum is more abundant in nature than copper, making it more readily available and less subject to supply fluctuations, which can affect the cost and long-term availability.

For these reasons, high-voltage lines typically use aluminum or aluminum alloys, often reinforced with a steel core (called ACSR, or aluminum conductor steel-reinforced cable) for added strength, combining aluminum’s lightweight and corrosion-resistant properties with steel’s durability.

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JJR