Flashover risk of ice-covered insulators increases significantly

and flashover characteristics vary with ice types. Through heat exchange analysis and force analysis of droplets

and changing the environment temperature

rainfall intensity and wind speed

the corresponding relationship between ice shape and density and environmental conditions was studied in this paper

the dry/wet growth determination model of ice growth was built

and the critical diameter of droplets corresponding one specific environmental condition was proposed. The research results show that

freezing process of droplets is affected by wind speed

temperature and its diameter. As environment temperature increases

insulator ice density increases while the bubble content in ice decreases. Ice density rises in general when rainfall intensity increases

and dry growth appears in some degree under lower rainfall intensity. High wind speed promotes the dry growth in ice generally. When wind speed increases to some certain extent

mixed-phase ice forms on the surface of insulators. As a whole

the difference between critical diameter and actual diameter of droplets is positively related with ice density

and there is a good consistency between ice dry/wet growth determination model and test results. The results of this paper can provide some certain references for ice shape prediction and flashover early-warning of transmission line insulators.