Open AccessInvestigations on the effect of ageing on charge de‐trapping processes of epoxy–alumina nanocomposites based on isothermal relaxation current measurements
Author(s) -
Maur Subhajit,
Haque Nasirul,
Pottekat Preetha,
Chakraborty Biswajit,
Dalai Sovan,
Chatterjee Biswendu
Publication year - 2020
Publication title -
iet nanodielectrics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.23
H-Index - 9
ISSN - 2514-3255
DOI - 10.1049/iet-nde.2020.0020
Subject(s) - epoxy , materials science , trapping , dielectric , isothermal process , space charge , composite material , relaxation (psychology) , dipole , nanocomposite , chemical physics , chemistry , thermodynamics , optoelectronics , psychology , ecology , physics , organic chemistry , quantum mechanics , electron , biology , social psychology
In this study, the relationship between thermal ageing and charge trapping properties of epoxy‐based nanocomposites has been investigated. With ageing, any dielectric material undergoes thorough degradation. This degradation significantly affects the space charge accumulation and charge trapping behaviour of the dielectric, which are very important parameters for insulation health under high‐voltage direct current (HVDC) environment. In this work, an improved model based on the isothermal relaxation current (IRC) has been developed to study the charge trapping behaviour of pure epoxy and epoxy alumina (Al 2 O 3 ) nano‐composites at different ageing conditions. A methodology based on polarisation–depolarisation current (PDC) measurements has been proposed to identify the current component due to a dipolar relaxation in measured total IRC. This will help to identify the trap distribution characteristics more accurately compared to conventional IRC measurements. It was experimentally observed that the addition of nanoparticles significantly reduces trapped charge formation and reduces thermal degradation. It is observed that aging leads to the generation of deeper traps, while the addition of Al 2 O 3 nanoparticles mainly enhances the density of shallow traps. Results presented in this work indicate that epoxy–alumina nanocomposites are very much suitable in HVDC applications from the perspective of trapped charge accumulation.