Pollution agglomeration characteristics on insulator and its effect mechanism in DC electric field

Abstract To obtain the pollution agglomeration characteristics of insulators and its effect mechanism of Ultra High-Voltage DC transmission lines under natural sedimentary condition, a natural pollution accumulation system was set up and used to analyze the micro-shape features of the surface insulators on different conditions. The experimental results show that the surface pollution is respectively distributed as chain and granular shapes on the DC charged insulator and electrically neutral insulator, which indicates that the pollution agglomeration characteristics are influenced by the DC electric field significantly. Meanwhile, the radius of the pollution particles on the DC charged insulator is larger than that on the uncharged insulator. Based on the thermodynamics and electrostatics theory, this paper proposed the model of electric dipole between aerosol groups to explain the characteristics of the pollution distribution on the surface of the DC charged insulator and revealed the mechanism of aerosol particles radius affected by DC electric field. The conclusions of this paper can provide an experimental and theoretical basis for the UHV DC external insulation pollution characteristics and insulator flashover.