A novel method to predict moisture in cellulosic insulation of power transformer with improved accuracy using time domain spectroscopy data

Researchers have shown that analysis of Time Domain Spectroscopy (TDS) data is an effective tool for condition assessment of oil-paper insulation system. Among various TDS data, Polarization-Depolarization Current (PDC) has gained popularity in recent times. Accuracy of non-invasive technique (like analysis of PDC data) has always been a topic of concern among utilities. This accuracy can be improved by better understanding of dielectric response function as a function of paper-moisture content and aging byproducts. In this research work, a non-linear relation between paper-moisture and some commonly measured insulation sensitive performance parameters is reported. Related analysis presented in the paper show that the proposed relationship, compared to other existing techniques, is capable of providing better accuracy in predicting paper-moisture value. The proposed technique is tested using data collected from several laboratory samples.