Counting the discs
Stories from Physics for 11-14 14-16
High voltage power lines typically use disc insulators to prevent current entering the metal pylon. Counting the number of discs can give an indication of the line voltage:
|Line Voltage (kV)||Number of discs|
When winds blow, high voltage power lines respond in three modes of oscillation: Gallop (0.1-0.5 Hz), Aeolian (8-60 Hz) and Wake-induced vibrations (0.5-2.5 Hz). Stockbridge dampers are dumbbell-shaped dampers consisting of two concrete or metal masses attached to a piece of cable or other flexible material. They reduce Aeolian vibration that can cause dangerous stresses in power lines.