At Ningbo Changshi Electric Power Machinery Manufacturing Limited, we understand the critical role of material science in power infrastructure. The choice of material for electrical transmission lines is a balance of electrical conductivity, mechanical strength, weight, corrosion resistance, and cost. The most common materials used for power line conductors are aluminum and steel, often combined in various configurations.

• Aluminum: Known for its excellent conductivity-to-weight ratio, aluminum is the most prevalent material for overhead conductors. It is lighter and more affordable than copper, making it ideal for long spans where minimizing weight on supporting structures is crucial. Its natural resistance to corrosion due to the formation of a protective oxide layer also contributes to its longevity.

• Steel: While steel has lower electrical conductivity, it possesses superior tensile strength. It is primarily used as a reinforcing core to provide mechanical strength to conductors, allowing them to withstand tension, high winds, and heavy ice loads without excessive sagging.

• Copper: Though it offers the best electrical conductivity, copper's higher cost, greater weight, and lower tensile strength compared to aluminum make it less common for high-voltage overhead lines. It is typically reserved for specialized applications like grounding or certain types of underground cables.

Common Conductor Types

To meet diverse project requirements, conductors are manufactured in various designs, each leveraging the properties of its materials:

• AAC (All-Aluminum Conductor): Made exclusively of stranded aluminum, AAC is lightweight and corrosion-resistant. It's a cost-effective option for low-to-medium voltage lines over short distances in urban areas.

• AAAC (All-Aluminum-Alloy Conductor): This conductor is made from an aluminum alloy (often with magnesium and silicon), which significantly increases its strength and resistance to corrosion compared to pure aluminum. AAAC offers a great balance of strength and conductivity, making it suitable for medium-distance lines, especially in corrosive or coastal environments.

• ACSR (Aluminum Conductor Steel Reinforced): This is the most widely used conductor for high-voltage and long-distance transmission. It consists of multiple strands of aluminum wrapped around a steel core. This design combines the high conductivity of the outer aluminum layer with the high tensile strength of the inner steel core, allowing for long spans with minimal sag.

In addition to conductors, other materials are crucial for power systems:

• Substation Busbars: These are typically made of solid aluminum or copper bars, chosen for their high current-carrying capacity and durability.

• Insulators: Made from materials like porcelain, glass, or composite polymers, insulators prevent the flow of electricity from the conductors to the supporting structures.