Fungi and algae behaviour on high-voltage insulators under environmental conditions

Abstract

Biological contamination of high-voltage insulators by fungi and algae threatens power system reliability, especially in humid tropical and subtropical environments. Field and laboratory data show that algal and fungal biofilms persistently reduce hydrophobicity and flashover strength under wet conditions. Dielectric analyses reveal that hydrated biofilms behave as lossy dielectrics with elevated permittivity and loss tangents, distorting local electric fields and accelerating surface degradation. The synergistic coexistence of algae and fungi intensifies the chemical, mechanical and dielectric deterioration of insulation materials. Microbial growth and persistence are strongly regulated by environmental factors such as humidity, rainfall, surface roughness and shading. By integrating microbiological behaviour with insulation engineering, this study establishes a unified framework for understanding biologically driven insulation degradation and informs predictive maintenance, material selection and mitigation strategies for high-voltage infrastructure operating in biologically aggressive environments.

Significance:

Biological contamination of high-voltage insulators poses an under-recognised reliability risk in climates characterised by high humidity and rainfall, such as those found across much of South Africa. This study demonstrates how algal and fungal growth alter surface dielectric behaviour, accelerate electrical ageing, and increase maintenance demand. By clarifying the environmental–biological–electrical coupling underlying these effects, the findings support more informed inspection, material selection and mitigation strategies for resilient power transmission infrastructure.