Percolation model for electrical breakdown in insulating polymers

It is suggested that an electric field above a given value eliminates the barriers to the transport of trapped charge carriers so as to produce an extended state in the form of a percolation cluster, and that the consequent current multiplication results in electrical breakdown. This model provides an estimated value of intrinsic breakdown strength close to the actual value. By considering the interactions between trap barrier potentials, the effect of electrical aging can be explained in terms of an increase in trap density. Many phenomena, such as the effect of weak points and the change of breakdown strength with the content of co-monomers or additives, can also be explained using this model.