Question

State any four properties of conductor material used for overhead conductor.

Answer 1

When selecting a conductor material for overhead power lines, certain key properties must be considered to ensure efficient and safe operation. Here are four important properties:

### 1. **High Electrical Conductivity**
   - **Reason:** The material must have low resistance to allow the free flow of electric current with minimal energy losses. High electrical conductivity ensures that power is transmitted efficiently over long distances.
   - **Example:** Materials like **copper** and **aluminum** are commonly used due to their excellent conductivity.

### 2. **High Tensile Strength**
   - **Reason:** Overhead conductors are subjected to environmental forces such as wind, ice, and the weight of the conductor itself. High tensile strength is needed to withstand these mechanical stresses without breaking or sagging excessively.
   - **Example:** **Aluminum conductor steel-reinforced (ACSR)** is often used, as steel provides the necessary tensile strength.

### 3. **Corrosion Resistance**
   - **Reason:** Overhead conductors are exposed to varying weather conditions, including rain, snow, and pollutants. A conductor material must resist corrosion to ensure long-term durability and reliability.
   - **Example:** **Aluminum** is preferred because it forms a protective oxide layer that resists further corrosion.

### 4. **Lightweight**
   - **Reason:** Lighter conductors reduce the mechanical load on the supporting towers and poles. This is particularly important in long-span transmission lines, as heavier materials would require stronger, more expensive infrastructure.
   - **Example:** **Aluminum** is favored over copper for high-voltage lines because it is much lighter while still offering good conductivity.

These properties are critical in ensuring that the conductor performs well under operational and environmental conditions while minimizing costs and ensuring safety.

Answer 2

For overhead conductors, the choice of conductor material is critical to ensure efficient power transmission and reliability. Here are four important properties of materials used for overhead conductors:

1. **Electrical Conductivity**: The material must have high electrical conductivity to minimize energy loss due to resistance. Aluminum and its alloys, such as ACSR (Aluminum Conductor Steel Reinforced), are commonly used because they offer a good balance between conductivity and weight.

2. **Mechanical Strength**: Overhead conductors must withstand mechanical stresses, including tension, wind, ice loads, and other environmental factors. Materials like steel and aluminum alloys are chosen for their strength-to-weight ratio, allowing the conductors to bear these loads without excessive sagging or breaking.

3. **Corrosion Resistance**: Overhead conductors are exposed to various environmental conditions, including moisture and pollutants. Therefore, the material must be resistant to corrosion and oxidation. Aluminum is naturally resistant to corrosion due to the formation of an aluminum oxide layer, which protects the metal underneath. Additionally, steel used in ACSR conductors is often coated or treated to enhance its resistance to rust.

4. **Thermal Expansion**: Conductors are subject to temperature variations, which cause them to expand and contract. The material should have a low coefficient of thermal expansion to minimize sag and ensure that the conductor remains within safe operational limits under temperature changes. Aluminum has a relatively high coefficient of thermal expansion, so it is often used in combination with other materials like steel to balance thermal performance and mechanical strength.

These properties ensure that overhead conductors perform efficiently and reliably in various environmental conditions.