Aprimoramento da inspeção visual de isoladores poliméricos por termografia e campo elétrico.

Abstract

This work presents an evaluation of the correlation between temperature and electric field to the improvement of polymeric insulators inspection. Samples of 138 kV polymeric insulators, intact and defectives, were submitted to electrical tests and thermographic measurements. Thus, the insulators removed from transmission lines were submitted to seven level of applied voltage and the thermographic measurements were realized once thermal equilibrium was established. The polymeric insulators were modeled and computational simulations of electric field were performed in the regions of interest. The results of the thermographic measurements, performed during the tests, showed higher temperature increases near the phase, when the defects are present. The results of the computational simulations of the insulators without external defects showed no electric field distortions. The analysis of defective insulators revealed that the electric field is distorted and its intensity depends on the defects’ configuration and position, corroborating with the temperature measurements. The results indicate the existence of a growth trend of the temperature at the points where the electrical field is more intense (superficial holes).