Electric Field Control in Polymeric Insulators by Optimizing Shed Location and Functionally Graded Material

Though composite insulators are gaining popularity in the power system networks, their failures due to electric field induced corona and local discharges pose a serious threat to their service duration. Electric field across the insulator should be limited below the threshold value to prolong the insulator life. This paper analyses the effect of Functionally Graded Material (FGM) on reducing electric field magnitude at the critical locations of the composite insulators. Finite element method is used for electric field computation and analysis. The introduction of FGM reduces the electric field at all critical locations of the insulator. The influence of FGM geometry and its relative permittivity is also studied. Additionally, the location of the first shed near the high voltage electrode of the insulator is also optimized for reduce electric field magnitude. Locating the first shed nearer to the first shed, increasing the thickness and relative permittivity of the FGM considerably reduce the electric field magnitude.