There is more pollution data for standard porcelain or glass insulator of UHVDC transmission lines but relatively less data for composite insulators. Most of them are not charged

which can not accurately obtain the comprehensive influence of electric field force

wind force

gravity

and other comprehensive effects on pollution accumulation characteristics of composite insulators during operation. In view of these existing problems

taking ±800 kV UHVDC transmission line as an example

this paper conducts a simulation analysis on the contamination accumulation characte-ristics of the operating composite insulators

and the substantial pollution degree of the composite insulators is measured and verified during the comprehensive inspection of the transmission line. The results show that the deposition of polluted particles on the surface of charged composite insulators results from the combined action of air drag force

gravity

and electric field force. The increase of the charged polluted particles and the enhancement of the electric field force has a more significant effect on the particle motion process

that is

the smaller the atmospheric wind force

the more obvious the effect of the electric field force on pollution accumulation. The equivalent salt deposit density of the umbrella skirt at the high-voltage end of the composite insulator on the UHVDC transmission line is higher than that at the middle and low-voltage ends. The whole string is distributed in a “U” shape

consistent with the distribution rule of the electric field along the string of charged composite insulators.