Remote assessment of high voltage insulators using wideband electromagnetic radiation signature

A novel approach for inspecting the condition of porcelain insulators based on statistical analysis of electromagnetic radiations of live insulators is proposed in this paper. Realistic replicas of punctured and contaminated insulators were created in the laboratory following IEC standards. These defective insulators were tested under high voltage stress while the electromagnetic radiations originated from the partial discharge activities on the insulators were captured using an electric field sensor. During the experiments, a multitude of tests were conducted and resulted in measuring and recording a total of 410,000 cycles of discharge activities. A feature extraction algorithm was developed to calculate the statistical features of the phase resolved interpretation of partial discharge pulses. The results of analyzing the extracted features from the radiated signature of defective insulators indicate that the scale and shape parameters of a two-sided Weibull distribution function, fit to the recorded measurements, entail distinct information about the source of discharges that can be used to identify the source of defects. Based on the library of features extracted from the recorded electromagnetic radiations, a support vector machine (SVM) classifier was developed which can successfully classify the radiation signature of punctured and contaminated insulators.