What is tracking in insulators?

• A. The progressive formation of conductive paths on the surface due to pollution and humidity, potentially leading to flashover.
• B. The progression of surface leaks along the insulator.
• C. The process of insulation material shrinking over time.
• D. The reflection of light from the surface.

Answer: (A)

Tracking is the formation of conductive paths on an insulator’s surface caused by pollution and humidity, which can become a channel for current to flow along the surface and potentially lead to flashover. When the surface is contaminated and wet, the resistance drops and ions move under the electric field, gradually creating persistent wet films or carbonized tracks that extend from one end of the insulator to the other. These tracks can bridge the gap at voltages well below where the material would normally break down, so pollution, moisture, and the condition of the surface all drive the process. Prevention focuses on keeping surfaces clean or hydrophobic, controlling pollution levels, and ensuring sufficient creepage distance to interrupt or suppress the formation of these conductive paths.