Answer: The mechanical design of overhead transmission lines is just as crucial as the electrical design, ensuring the line's structural integrity and longevity. Key considerations include:

• Sag and Tension: This refers to the vertical dip (sag) of the conductor between two support points and the pulling force (tension) exerted on the conductor. These two factors have an inverse relationship; an increase in one causes a decrease in the other. Sag and tension calculations must account for the conductor's weight, the span length between towers, and environmental conditions such as ice loading and wind pressure.

• Clearance: The design must ensure adequate clearance distances are maintained between the conductors and the ground, as well as between different conductors or phases. This is vital for public safety and to prevent electrical flashovers, especially in varying weather and temperature conditions.

• Environmental Factors: The design must account for the forces exerted by external elements like wind and ice. High winds can cause significant mechanical stress and conductor oscillation, while ice buildup can dramatically increase the conductor's weight, requiring robust support structures and proper sag and tension management.