The basin insulator is the most important insulating part of Gas Insulated metal closed switch（GIS）

and its performance can directly affect the operation life of GIS. In this paper

some sample of 252 k V basin insulatorsare used to do the corresponding characteristics test in kunming UHV Test Base

and the three dimensional electricfield simulation and stress simulation model is set up based on conditions in the experiment

check the basin insula-tor and the insulation of the busbar structure design and mechanical stress design

and the basin insulators under dif-ferent load design margin is clear combined with zero gage pressure test and water pressure test results

and perti-nent equipment selection and follow-up optimization suggestions are put forward. Research results help to under-stand the differences in design principles and technical details

and through the various product design margin ofquantitative evaluation and examination

and provide the reference for 252 k V GIS equipment selection and opera-tion maintenance.