Reliable Sensing of Insulation Sensitive Performance Parameters Using Time Domain-Based Measurement at Different Temperatures

The amount of moisture and conductivity are the two crucial parameters that signify the condition of oil-paper insulation (OPI). The reliable sensing of moisture and conductivity of solid insulation requires a fully measured profile of polarization-depolarization current (PDC) data, which is monotonically decaying in nature. The measured PDC data are significantly influenced by measuring temperature. Hence, sensed values of insulation sensitive parameters may provide ambiguous information related to insulation state due to temperature variation. In the present work, an efficient method is suggested, which can be used for sensing crucial performance parameters (such as paper moisture and paper conductivity) using the dielectric response measured at various temperatures. The proposed methodology provides an easy way to sense paper moisture and paper conductivity that will be independent of the measured temperature. In order to test the capability of suggested method, the analysis is performed on the data collected from in-service power transformer insulation. Research findings show that the proposed technique can be applied to data collected from in-service power transformers for sensing insulation condition-sensitive parameters.