Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

This paper presents a numerical investigation based on 3D finite element method modeling of a dead-end 28 kV non-ceramic insulator having different internal semi-conductive defects in terms of size and position. All the internal defects were modeled as cylinders of 1.5 mm of radius having different lengths: 15 mm and 30 mm which correspond to 3.5 % and 7 % of the insulator length respectively. The internal defect was positioned close to the HV electrode and in the middle of the insulator (floating potential) at equal distance between the sheds. The simulations have been focused on the modification of the axial and radial E-field components closed to the insulator shank surface as well as at the vicinity of the insulator shed extremity. The results obtained demonstrated that small conductive internal defects (lower than 3.5 % of the insulator length) led to a significant distortion of the axial and radial E-field components at the shank surface. The E-field component distortion obtained for a small defect (floating potential) positioned in the middle of insulator between sheds is detectable at the shank surface but invisible at the shed extremity.