Electrical Treeing of Epoxy Resin under Tensile and Compressive Stresses

Abstract

In this paper, the morphological characteristics of electrical tree in epoxy resin under tensile and compressive stresses were investigated when the applied mechanical stress was parallel to the direction of the electric field. The applied tensile and compressive stress varied between 0 and ± 30 MPa with a direction parallel to the needle-to-needle electrodes. The results show that tensile stress promotes the growth of trees in perpendicular direction to the needle axis. The greater the tensile stress, the more divergent the electrical trees are, and the greater the accumulated damage is. The compressive stress inhibits the growth of trees in perpendicular direction to the needle axis. The greater the compressive stress, the less divergent the electrical trees are, and the greater the accumulated damage is. Moreover, the applied stress has little effect on the growth rate of the electrical tree in the direction parallel to the stress. Results of this paper are helpful to understand the bursting breakdown phenomenon of tri-post insulators in GIL.