Investigation of Electric Field Effect on Space Charge Dynamics of Epoxy-TiO2Nano-Composites Using IRC and QCC Analysis

This paper investigates the effect of electric field on charge trapping characteristics of the epoxy and TiO2 nano-composites based on isothermal relaxation current (IRC) and quantum chemical calculation (QCC) analysis. For this purpose, two types test samples are prepared i.e. pristine epoxy and epoxy with 0.5wt% $\text{TiO}_{2}$. The experimentation of IRC measurement is conducted under three different electric field stress (i.e. 1.5kV, 2kV and 2.5kV). From the IRC, the detrapping current is extracted and further, the trap charge distribution (i.e. the trap density under different trap depth) with the varying electric field stress are evaluated. Apart from that, in QCC, two different molecular structures (i.e. epoxy and epoxy/ $\text{TiO}_{2}$) are geometrically optimized, and their molecular energy level distributions are studied under no-field and 0.001 a.u. field stress conditions. Finally, a correlation is established in-between the trapping characteristics (i.e. space charge dynamics) and the QCC based molecular energy level distribution of epoxy/TiO2 nano-composite insulation.