Keeping all other factors the same, if span length is doubled the sag of the transmission line will become

Keeping all other factors the same, if span length is doubled the sag of the transmission line will:

1. Half
2. Double
3. Triple
4. Quadruple

Correct answer: 4. Quadruple

Keeping all other factors the same, if span length is doubled the sag of the transmission line will quadruple.

Formula for sag is:

Sag = wl²/8T

Keeping other factors same

Sag ∝ l²

Let’s assume orginal sag

Sag(1) ∝ l²

Now when span is doubled

Sag(2) ∝ (2l)²

Sag(2) ∝ 4.l²

Sag (2) ∝ 4.Sag(1)

So, while Keeping all other factors the same, if span length is doubled the sag of the transmission line will become 4 times the original sag.