Study On The Effect Of Green Algae Growth On The External Insulation Of Composite Insulators

Composite insulator is a key component in power transmission and transformation system.Its running state is directly related to the safe and stable operation of power system.In recent years,biological attachment has been found on the surface of some composite insulators running in warm humid regions of the world,which has attracted the attention of experts and scholars.Green algae are the most common organisms on the surface of composite insulators.The effect of green algae as a special biological fouling on the external insulation performance of composite insulators is not clear.The growth and propagation of green algae on the surface of silicone rubber are accompanied by a series of physicochemical processes,which may affect the properties of silicone rubber.As organic organisms,green algae themselves have higher electrical conductivity.The attachment of composite insulators may affect their electrical properties.In this paper,the effects of epiphyte on the external insulation of composite insulators are studied from four aspects: hydrophobicity,micromorphology,alternating and direct flashover characteristics and the axial electric field distribution of composite insulators.1)The distribution characteristics and epiphytic process of green algae on composite insulators sheds were analyzed with 500 kV AC composite insulators attached to green algae in Guangdong area.The surface hydrophobicity of the sample silicone rubber sheds of green algae was measured by the static contact angle method,and the effect mechanism of green algae on the surface hydrophobicity was studied by EPMA electron probe surface chemical analysis.2)Under scanning electron microscope(SEM),the influence of green algae epiphyte on the micromorphology of composite insulators silicon rubber sheds was studied at 50-5000 different magnification rates,and the mechanism was analyzed.3)The electric field simulation model of 500 kV composite insulators was established by the finite element method.The attachment of green algae was set up according to the distribution characteristics of the axial green algae in the composite insulators in the operation.The distribution characteristics of the axial electric field of the insulators on the composite insulators were studied by COMSOL.At last,the influence of electric field distribution on insulators is analyzed theoretically and experimentally.4)The green algae covered silicone rubber samples were prepared by evaporation drying method with high temperature vulcanized silicon rubber sheet as the substrate.The AC and DC flashover characteristics of silicon rubber sheet with different green algae epiphytic width under drying conditions and wetting conditions were studied by uniform pressure boosting method.The actual operation conditions were analyzed according to the test results.