The particle size distribution of the contaminated particles on the surface of the insulator is of great significance for the study of pollution flashover characteristics of the insulator. In this paper

the particle size distribution characteristics of contaminated particles of different types of insulators are studied by way of carrying out natural contamination test. The process of contamination accumulation of the composite insulators is analyzed emphatically. The physical model of deposition and accumulation of particulate matters on the surface silicon rubber is set up. The formation mechanism of particle distribution on the surface of composite insulator is analyzed by means of simulation software and

at the same time

the influence of charge accumulation effect on contamination is also discussed. The results show that the average size of the contaminated particles on the surface of composite insulators is slightly larger than that of porcelain and glass insulators and the particle size distribution shows the law of log-normal distribution

showing the concentration within the range of 20～30 μm. In addition

in case of existing accumulated charge on the shed surface

the ability to absorb large-size particles will increase

thus the amount of surface contamination and average size of particles will become larger.