Previous Year Question
Why are ground wires installed at the top of 400 kV transmission towers?
Correct answer: B
Explanation
Overhead ground (shield) wires are positioned above the phase conductors to intercept direct lightning strokes and conduct the surge current safely to earth through the towers. Their principal purpose is lightning shielding.
Step-by-step solution
Correct Answer
B — To provide shielding of phase conductors from lightning strokes
Explanation
Overhead ground (shield) wires are positioned above the phase conductors to intercept direct lightning strokes and conduct the surge current safely to earth through the towers. Their principal purpose is lightning shielding.
Key Concept
Overhead Ground/Shield Wire
Exam Point
Top shield wire = lightning interception and earth path.
Exam tip
Top shield wire = lightning interception and earth path.
Quick method
Top shield wire = lightning interception and earth path.