Evolution Of Insulator Performance In Outdoor Transmission Lines

In complex field weather conditions, the operating status of power systems is closely related to the durability of external components. When porcelain dead end insulators is exposed to air for a long time, it is subjected to the combined effects of ultraviolet radiation, temperature difference cycles, and atmospheric humidity, which will cause irreversible and subtle changes in its surface physical properties.

Analysis of the Causes of Insulator Material Deterioration

Multiple factors in nature combine to induce aging signs in equipment during service. Rain and fog increase air humidity, leading to moisture accumulation on the surface of the insulator skirts. Wind and sandstorms, along with the adhesion of chemical pollutants, damage the original smoothness of ceramic or composite materials. This environmental stress leads to a slow decline in insulation performance.

In actual operation, the following factors have a profound impact on the health of insulators:

• Photo-oxidation reaction: Ultraviolet rays in sunlight decompose polymer molecular chains, inducing surface cracking.

• Contamination characteristics: Airborne particles deposit under the influence of gravity and electrostatic fields, forming a conductive contaminant layer.

• Partial discharge: Dry electric arcs generated after surface wetting can burn the material, reducing breakdown strength.

Evolution of Surface Hydrophobicity and Electrical Strength

With increasing service life, the hydrophobicity of suspension insulator exhibits significant phased fluctuations. Initially, the material exhibited good resistance to water spread, but this property was temporarily lost when suspension composite insulator was exposed to air for a long time due to the consumption of surface chemical functional groups. Although some composite materials exhibit hydrophobic migration, long-term environmental erosion still leads to a substantial reduction in insulation distance.

In power grid operation and maintenance, monitoring of the composite suspension insulator condition typically focuses on the fluctuation trend of leakage current. When the concentration of air salt spray exceeds the standard, the probability of flashover increases. Maintaining the reliability of power grid operation is essentially a game against the rate of material aging.