Electrical aging and life models: the role of space charge

TLDR

Space charge–aging interactions in polymeric insulation are a widely debated topic with significant implications for the design of electrical equipment and insulating materials. This review aims to evaluate aging models that incorporate or neglect space charge, clarifying their validity under DC and AC conditions. The authors compare conventional phenomenological models that ignore space charge with those that treat it as a driving force or as a degradation consequence, assessing how each accounts for electric field and activation energy effects.

Abstract

This paper has the aim of providing a view of a lively debated topic which has broad impact on the design of electrical apparatus and new insulating materials, that is, the interaction between space charge and aging processes of polymeric insulation. Aging models developed in recent decades that consider explicitly or implicitly the contribution of space charge to insulation degradation, under both DC and AC voltage, are dealt with, with the intention to point out their range of validity. Some conventional phenomenological models that have been used for much more than two decades without referring to space charges can be exploited to account for electrical field and activation energy modification due to space charge. These, together with models conceived considering space charges as the driving force for aging, are especially examined. In addition, recent models that disregard the action of space charge as an ageing factor, but consider space charge as the consequence of degradation processes are also discussed.