A model of solid dielectrics aging

摘要

A simple aging model based on a modified version of the Eyring rate equation is presented that describes very well the electrical and mechanical aging of polymer dielectrics. In particular, the electrical aging of XLPE (cross-linked polyethylene) cables is well described. It is also shown that the onset of irreversible electrical aging occurs above a critical field whose value can be predicted by the proposed model. This corresponds to the formation of submicrocavities whose average size is controlled by the amorphous phase length of the polymer.