When the high voltage equipment in a high altitude area over 1000 m

it can cause electrical equipment reduce the strength of external insulation. In order to solve external insulation design problem of converter valve at high altitudes

in this paper

combined with external insulation design for ±500 k V light trigger thyristor converter valve of Yong Ren station（at an altitude of 1 800 m）

g parameter method is used to calculate the minimum air distance for the key position of valve module and valves tower

at the same time

Ansys software is used for simulation analysis and related test was carried out to verify. The results has guiding significance for the valve structure design

also suggests that external insulation design for Yong Ren converter valve is reasonable

it can satisfy the operation requirement at high altitude area.