Sand environment along Lanzhou-Xinjiang high-speed affects the contamination distribution on the roof insulator surface of electric multiple units（EMU）

which can result in EMU ‘break down’ faults under humid climate conditions. In a closed wind tunnel

the contamination time on the surface contamination distribution of the EMU roof epoxy resin insulator at the speed 200 km/h were experimentally investigated. The results show that

the contamination distribution on insulator surfaces tends to be in fan-shaped non-uniform distribution

leeward contamination density is the heaviest

and the contamination density of top surface is greater than that of the bottom except the 7th sheath. From 2 h to 20 h

the top surface contamination density of the leeward side increases with the contamination time

increasing. When the time is 20 h

the pollution density tends to be saturated and the value can be up to 5.6 mg/cm

2

. When the leeward side number is taken as a reference

the ratio of the windward and the crossward side density to the leeward side becomes smaller with a prolongated contamination duration. The research results can provide the basis for insulator flashover tests and insulator structure optimization design under the wind sand environment of Lanzhou-Xinjiang high speed railway.