Influence of Separated Globules on Post Insulator Electric Field Distribution

Separated globules of hydrophobic surface will distort electric field,which will cause partial discharge.Consequently,we established a 110 kV porcelain post insulator and simulative composite post insulator model on the basis of the finite element method,obtained the surface electric field/potential of insulator with separated globules,which was compared with the condition without globules,and obtained the region generated partial discharge easily.Moreover,the field strength distortion scope of globules was analyzed,and the influences of contact angle,globule distance and conductivity on the field strength were analyzed.The result indicates that the separated globules have no influence on the whole electric field and potential distribution but distort the neighboring electric field.Electric field distorts badly nearby hardware fitting and section between parachute skirt upper surface and cylinder.The electric field is only distorted within a small range of large sheds lateral side;surface field strength of composite post insulator is slightly less than that of the same shape porcelain post insulator.The electric field will become more serious with the increase of contact angle and decrease of globule distance,and the field strength has nothing to do with the water conductivity.