Conductor sag refers to the vertical dip or curve that an overhead conductor makes between two support points (towers or poles). It's a critical factor in OHTL design for several reasons:

• Safety Clearance: Sag determines the minimum vertical distance between the conductor and the ground, as well as other objects like buildings, roads, and trees. Maintaining adequate sag is essential to prevent flashovers, electrical hazards, and ensure public safety.

• Conductor Tension: Sag is inversely proportional to conductor tension. A tighter wire (less sag) has higher tension, which can increase the risk of mechanical failure or breaking, especially under heavy loads from ice or wind.

• Environmental Factors: Sag changes with temperature, ice loading, and wind pressure. We must perform careful sag-tension calculations to ensure the line operates safely under all potential weather conditions, preventing the conductors from coming into contact with each other or the ground.