Which device is installed on lines experiencing prolonged vibration to prevent conductor fatigue?

• A. ACSR wire
• B. New insulators
• C. Vibration dampers
• D. All of the above

Answer: (C)

Vibration dampers are used because wind can set lines into repetitive motion (aeolian vibration) near supports, which subjects the conductor to cyclic tension and can cause fatigue cracks over time. These dampers absorb energy from the oscillations and reduce how much the conductor moves, lowering peak strains at the clamps and slowing fatigue crack growth. A Stockbridge damper is a common type, with a weighted section that dissipates energy as the line oscillates. The other options aren’t damping devices by themselves—the conductor type (ACSR) and insulators serve electrical and mechanical roles, not specifically to curb vibration-induced fatigue—so they don’t address the fatigue issue the way dampers do.