Percolation model for electrical breakdown in insulating polymers

A percolation model for intrinsic breakdown in insulating polymers is presented, which indicates that an extended state for charge carriers can be formed due to the reduction of the trap barriers at a high enough electrical field, and that breakdown can be induced by the current multiplication in the extended state. This model provided an estimated value of breakdown strength close to the actual value. By considering the interactions between trap barrier potentials, the effect of electrical aging can be explained in term of an increase in trap density. Many phenomena, such as the effect of weak points, the change of breakdown strength with the content of comonomers or additives, and the changes in electroluminescence during electrical tree initiation can also be explained using this model.