Electrical transmission lines are a complex system with three primary components: conductors, ground wires, and supporting structures. The choice of material for each component is crucial and depends on factors like conductivity, mechanical strength, cost, and environmental conditions.

1. Conductors: The most vital part of the line, conductors are the "wires" that carry the electricity. Historically, copper was used due to its excellent conductivity, but aluminum has become the dominant material for modern overhead lines. Aluminum is lighter and less expensive than copper, making it ideal for long-distance transmission. To overcome aluminum's lower tensile strength, various types of conductors are used:

• AAC (All-Aluminum Conductor): Made of stranded aluminum wires, these are lightweight but have lower strength. They are best suited for short-span applications.

• AAAC (All-Aluminum-Alloy Conductor): These conductors use a high-strength aluminum alloy, providing better mechanical properties and corrosion resistance, often used in coastal or high-corrosion environments.

• ACSR (Aluminum Conductor Steel Reinforced): This is the most common type for high-voltage transmission lines. It combines the high conductivity of an outer layer of aluminum strands with the exceptional strength of a central steel core. The steel core provides the necessary tensile strength to support the conductor over long spans with minimal sag.

2. Ground Wires (or Shield Wires): These wires are located at the very top of the transmission towers. Unlike conductors, they do not carry current under normal conditions. They are made of materials like steel and are designed to absorb and deflect lightning strikes, protecting the live conductors below and grounding the electrical surge safely.

3. Supporting Structures (Towers and Poles): These structures hold the conductors and ground wires at a safe distance from the ground and other objects. They are primarily made of galvanized steel in a lattice or tubular design. The use of galvanized steel ensures durability and corrosion resistance. In some cases, reinforced concrete poles or even wood poles are used, depending on the voltage level and geographical location.

At Ningbo Changshi, we specialize in providing the essential tension stringing equipment and underground cable laying equipment required to install these critical components. Our tools are designed to handle a wide array of conductor types and support structure materials, ensuring efficient and safe construction of overhead and underground power line projects worldwide.