Snow will threaten the reliability of a power system. Therefore

it has important engineering value and significance to calculate the electric field distribution along the surface of snowed composite insulators. In this paper

the authors put forward the triangle model of snow. And how the snow shape and parameter affects the electric field along the surface of composite insulators on 110 k V transmission lines on high altitude is studied through the quasi-static electric field finite element method. The two-dimensional axial symmetry models of the snowed composite insulators are given to study electric field distribution along the surface

after changing area and height of snow on the large sheds

air length and position when the large sheds are completely bridged by snow. Also the snow parameters’ influence on the electric field along the surface is analyzed. The results show that

when snow only exists on the large sheds

snow height and thickness have little influence on electric field distribution along the surface. And electric field distribution along the surface has improved when the large sheds are completely bridged by snow. The maximum field intensity of insulators increases with the increase of relative permittivity when snow only exists on the large sheds. Electrical resistivity has no influence on the electric field along the surface.Snow parameters seriously changed would threaten the electrical insulation properties of the insulators when the large sheds are completely bridged by snow.