Condition Assessment of Epoxy Nanocomposites Using Polarization and Depolarization Current

Abstract

Condition assessment allows us to identify the insulation failure which may further lead to hardware failure. By using condition assessment, maintenance can be done in a scheduled manner or some other precautions can be taken up to avoid the failure. The observation and analysis of the dc conductivity and dielectric response function is a feasible way to diagnose the main insulation condition, and the same applied for epoxy insulation. This PDC work, is focussed on polarization and depolarization current measurement which can be used for evaluating the quality of epoxy insulation. This technique is a time domain based method for evaluating the conductivity of insulation and moisture content in solid insulation materials. This work presents a description of the PDC measurement technique with the quantitative modelling of epoxy insulation used. A relation is established among the equivalent circuit model parameter of the epoxy insulation and the dissipation factor of this insulation. By knowing the equivalent circuit parameter from the depolarization current of epoxy insulation, the conductivity and dissipation factor is obtained which is observed to be increasing with respect to the increasing thermal aging duration.