Improved physical model of electrical lifetime estimation for crosslinked polyethylene AC cable

Abstract

Inverse power model (IPM), which is a phenomenological model that can predict the electrical life of crosslinked polyethylene (XLPE) insulation, is commonly used to design the insulation and test voltage of cables. Unfortunately, IPM cannot reflect the physical process of electrical aging, and the parameters have no physical significance, which limits the application range and extrapolation accuracy of IPM. Although the physical models of electrical life based on physical and chemical degradation processes exhibiting high accuracy are available, the equations of physical are complex to be popularized in engineering applications. In this paper, a new physical life model for engineering application is presented based on the relationship between transition-state theory and IPM. The proposed model considers the effects of AC electrical stress and thermal stress on aging. The proposed model is fitted to the life data of AC XLPE cable, thus confirming the validity of the proposed model.