Simulation of the developed electro-thermal aging model based on trapping and detrapping process

The key aspect of this work is to simulate the evolution of structure damages in polyethylene under the effect of electro-thermal stresses based on the trapping and detrapping aging model. In addition, the susceptibility of the model parameters to the isolated sites during the aging period have also been studied. The simulation work is performed on a 2D square grid that is assumed to represent a part of the insulation. The mesh structure is divided using the finite element method. Based on the nature of polyethylene, its structure is semi-crystalline with a spatially varying morphology. Consequently, each bond in the grid is assigned a set of parameter values. One of these parameters is the critical fraction of trapped charges C*, which needs to be reached in order to fail a bond. It is chosen at random values from a range centered on the characteristic value obtained from the experimental results. This indicates that the insulation life at varying parameter C* is lower than its characteristic value.