Question

for a 66 kv line having span of 200 meters between towers the approximate sag will be 2 m. if the span is double the sag will be:

Answer 1

The sag is given by the formula,

$S=\frac{wL^2}{8T}$, where $L$ is span, $w$ is the weight per unit length of the conductor and $T$ is the tension in the conductor.

The sag is proportional to the square of span.

When the span doubles, the sag becomes 4 times. So the new sag will be $4*2=8\;m$.