Physicochemical Characteristics and Dynamic Charge Mapping in Thermally Aged Two-Layered Polymer Considering Surface States: Experiment and Simulation

Abstract

Under operational conditions of high electric fields and elevated temperatures, the accumulation of space charges at multilayer insulation interfaces is often considered as an important factor affecting insulation performance. This study experimentally explored the influence of different thermal aging degrees (110 °C for 0, 720, 1600, 2100, and 2900 h) on physicochemical characteristics. The space charge dynamics in two-layered thermally aged PET-PET films were measured using the pulsed electro-acoustic (PEA) method and simulated on the basis of a one-dimensional modified bipolar charge transport model. The parameterization for key parameters involved in the model was analyzed through parameter sensitivity. Results indicated that the molecular structure, crystallinity, and dielectric spectra of the PET films are affected by thermal aging. The thermalization process also has noticeable effect on the surface state characteristics, which are characterized by deeper trap depth and larger trap density. Several experimental phenomena measured by the PEA method were observed on the basis of numerical simulation.

Dielectric polymer nanocomposites: Past advances and future prospects in electrical insulation perspective

“…Fischer and Rohl [ 100 ] suggested that oxidation induces clustering of carbonyl groups (C═O), resulting in the rapid movement of the mobile charge carrier and increased CC density. Jiang et al [ 101 ] presented experimental and simulation studies for dynamic charge mapping in thermally aged two‐layer PET‐PET films. Thermal aging caused an increase in space charge polarization, which increased permittivity in the low‐frequency region.…”

Modified Molecular Chain Displacement Analysis Employing Electro-Mechanical Threshold Energy Condition for Direct Current Breakdown of Low-Density Polyethylene

“…The study of space charge measurement has been conducted for several decades with various methods, such as pulsed electro-acoustic (PEA), pressure wave propagation (PWP), laser induced pressure pulse (LIPP), and current integration (Q(t)) methods, etc. [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Numerical analysis of space charge and electric field has been actively conducted with the conductivity and bipolar charge transport (BCT) models [ 21 , 22 , 23 ].…”