Computation of thermal, electrical, and mechanical fields at a defect in polyethylene

Power frequency voltage and lightning surges cause space charge formation and power dissipation at defects in high voltage systems. In the case of lightning impulses, the power dissipation can cause substantial temperature rise in the dielectric which results in mechanical stresses from space charge and non-uniform thermal expansion induced forces. Two-dimensional transient nonlinear finite element analysis has been applied to compute the space charge, power dissipation, temperature rise, and mechanical stress at a defect in XLPE.