Meaning
Continuous high-voltage stress across solid insulation can cause progressive degradation of the material’s surface, leading to electrical breakdown. Surface tracking erosion occurs when repeated electrical scintillation events wear away the polymer or resin, creating deep grooves and conductive channels. This progressive wear decreases the insulation thickness and increases the risk of a complete dielectric failure.
It is a major concern for outdoor electrical grids and industrial switchgear, where exposure to rain and pollution accelerates the physical deterioration of the components.
Degradation Pathway
Moisture and airborne contaminants form a conductive layer on the insulator, which initiates surface tracking when exposed to high voltage. The heat from leakage currents dries out parts of this layer, causing small electrical arcs to jump across the dry bands. These arcs burn the surface, slowly eroding the insulation and leaving behind conductive carbon paths.
Electric Arc
High-voltage systems must be designed to withstand these small, localized arcs without triggering a full system failure. If the erosion progresses too far, the electric arc can bridge the entire insulator, causing a short circuit. This event can result in expensive damage to transformers and other critical grid infrastructure.
Protective Coating
Manufacturers apply specialized hydrophobic coatings to insulator surfaces to prevent the formation of a continuous moisture film. These coatings repel water, which reduces leakage currents and limits the occurrence of surface scintillation. This simple protection extends the operational life of the equipment and reduces the need for frequent manual cleaning.
