Design optimization of polymeric insulators using reduced dimension modeling

Abstract

Polymeric insulators also known as non ceramic or composite insulators are now increasingly used for outdoor applications for all voltage classes due to their advantages over traditional ceramic and toughened glass insulators Some of the advantages include light weight ease of installation lower cost resistance to vandalism and better pollution performance due to the hydrophobicity of the housing material Despite these advantages insulation design of polymeric insulators is still an area of concern The main reason is that the electrical field is non uniform when compared to ceramic insulators due to the absence of intermediate metal parts which provide a certain degree of stress grading newlineCorona and grading rings are used to make the electrical field more uniform thereby improving the insulation design of polymeric insulators Depending on composite insulator design insulator set string configuration and applied voltage the number and type of ring coronagrading or both varies The exact dimensions location of rings are not discussed yet in any of the standards and hence inappropriate grading lead to increase in electrical field and also increase in the basic insulation level Hence the necessity to determine the optimum dimensionslocation of the rings using electrical field distribution along the polymeric insulators arises newline newline