Effect Of Fog-Haze Adsorption Characteristic On Insulating Properties Of Outdoor Insulator

With the develop of industrialization and urbanization,fog-haze weather occurs frequently in winter,especially in northern China.Different from the natural pollution,the fog-haze weather will increase the contamination and wetting degree of the insulator at the same time,resulting in the conductivity of contamination on the insulator surface increasing in a short time,raising the risk of flashover of the insulator.Based on the analysis of the physicochemical properties of fog-haze particles,this paper analyzed the contamination characteristics discharge and flashover properties of insulators,and predicted the contamination degree and flashover voltage in fog-haze environment.the physicochemical properties of the fog-haze particles adsorbed on the insulator surface were studied by analyzing the elemental composition,anion and cation concentration,microscopic morphology and particle size distribution of the contaminated surface on the insulator during the fog-haze.The result shows that fog-haze particles on insulator surface are mainly composed of O,Al,Ca,Si,Na,Mg,S,Cl,and Fe,K,Zn.The cations mainly include Ca²⁺、Zn²⁺、Na⁺、K⁺、Fe²⁺and Mg²⁺.The anions are mainly F^-,Cl^-,NO₃^-,SO₄^2-.The haze particles are mainly composed of irregular massive particles.Spherical particles,near cuboid particles and dense chain particles are occasionally found.The particles surface is rough,and fine particles,with a particle diameter of less than 5μm are adsorbed on it.The particle size distribution ranges from 1.5μm to 52.73μm.The D50 is about 13μm.Based on the self-design fog-haze simulation test device,the contamination test of the insulator was carried out,and the influence of the variation of different typical fog-haze parameters on the equivalent salt deposit density（ESDD）and non-soluble deposit density（NSDD）of the contamination layer was studied.The result shows that with the increase of the fog-haze duration and fog-haze concentration,and with the reduction of the particle size,the ESDD and NSDD increase.The increase of fog conductivity and relative humidity will increase the ESDD,but it has little effect on the NSDD.With the of soluble ionic component,the ESDD increases and the NSDD decreases.The fog component has little effect on both of them.The application of voltage at the insulators causes the ESDD and NSDD increasing slightly,and effect of DC is greater than AC.The discharge and flashover test in the simulated fog-haze environment were carried out,analyzing the effects of different typical fog-haze parameters on the leakage current and flashover voltage.The results show that with the increase of fog-haze duration,fog-haze concentration,fog conductivity,relative humidity,soluble ionic and conductive components,and with the decrease of particle size,the leakage current increases and the flashover voltage reduces.The fog composition has little effect on it.Based on the neural network method,the prediction model of pollution degree and flashover voltage of insulators in fog-haze environment were established.The model set the fog-haze environmental meteorological parameters and leakage current as input,and predicted the contamination degree flashover voltage.The prediction results were evaluated by experimental data,and the maximum relative error satisfied the engineering needs.