Insulation structure design is one of the core issues in UHV electrical design

and is essential to the safe operation of products.This paper calculated and analyzed the electric field intensity of 1 000 kV SF6 gas insulated voltage transformer via finite element method.Several groups of results were compared

and some key points were proposed for the high voltage electric device insulation design and other ultra high voltage electric device design with similar structure.It is found that for high voltage apparatus of SF6

the effective measures to improve casing potential distribution and reduce electric field intensity are setting up shielding pressure

and reducing the maximum electric field intensity by means of choosing reasonable compression ratio K

increasing curvature radius or using multi-curvature arc

etc.For other 1 000 kV SF6 gas insulated UHV appliances with similar structure

capacitive voltage dividing principle can be applied to their insulation design

and two or more shielding pressure can be set up when necessary.However

the increasing number of shielding pressure will bring great difficulty to processing and assembling

therefore the number should be reasonable.