Analysis Of The Impact Of Increased Ambient Humidity On Insulator Performance

In humid environments, a water film easily forms on the surface of polymer deadend insulator, leading to an increase in surface leakage current. This is particularly pronounced under prolonged high humidity conditions, potentially causing partial discharge and decreased insulation performance. Humidity changes directly affect the withstand voltage capability of porcelain dead end insulators, especially in high-voltage lines and power distribution systems. Increased humidity accelerates contaminant adsorption and alters the surface electric field distribution of suspension insulator.

Relationship between surface water film and leakage current

Increased humidity leads to a thin water film covering the surface of suspension composite insulator, and the thickness of the water film is positively correlated with ambient humidity. After the water film forms, the surface conductivity of the composite suspension insulator increases, which may cause fluctuations in leakage current.

• Micro-water film stage: The water film thickness is insufficient to form a continuous conductive path, but the surface resistance decreases significantly.

• Continuous water film stage: The water film forms a conductive path, resulting in a significant increase in local current and frequent partial discharge phenomena.

• Impact of Adhesive Contamination: Dust and contaminants in the air easily deposit on the water film, forming conductive bridges and further affecting insulator performance.

This phased effect illustrates that the electrical performance of insulators varies significantly under different humidity levels, and the combined effect of humidity and surface condition must be considered.

Humidity Variation and Insulator Aging

Fluctuations in ambient humidity accelerate the aging of insulator materials. In high-humidity environments, the internal structure of silicone rubber or porcelain insulators may undergo microscopic changes after absorbing moisture. Long-term, repeated cycles of wetting and drying can lead to surface cracks, reducing mechanical strength and withstand voltage.

Humidity also affects the growth of microorganisms on the outer surface of insulators, especially in warm, humid environments, where biological contamination can further alter surface electrical properties. This complex humidity effect necessitates a thorough consideration of the multifaceted impact of humidity on performance during insulator maintenance and testing.