Equivalent GMD of Transposed Line

Correct Answer

D — ∛80 m

Explanation

For a transposed 3-phase line, equivalent mutual GMD is the cube root of the product of the three mutual spacings. Thus Dm = ∛(4×4×5) = ∛80 m.

Key Concept

Equivalent GMD of Transposed Line

Formula

Dm = ∛(Dab Dbc Dca) = ∛(4×4×5) = ∛80 m

Exam Point

Three mutual distances → multiply all three, then take cube root.

Common Mistake

Do not take a square root; a 3-phase transposed line uses the cube root of three spacings.