External insulation design of converter stations for Xiangjiaba-Shanghai ±800 kV UHVDC project

External insulation is one of the critical aspects in the HVDC equipments and converter station design. Especially for UHVDC converter stations, the long creepage and clearance required has significant impact on the equipment and station design. The external insulation design of DC yard, valve hall, and for converter valves is presented. It is the intention of this report to review and summarize the work that has been done and the decisions that have been taken to the benefit of further work and design of new projects.