Studies on the Criteria for the Classification in Complementary Predictive Techniques Applied in the Analysis of the Insulation System of Power Transformers

This article presents studies on various predictive techniques (referred to herein as complementary) related to the insulation system. In combination with other existing techniques, these complementary techniques, whose test classification criteria are demonstrated by scores ranging from "A" (excellent) to "E" (very poor), are important for the diagnosis of power transformers. These techniques are particle counting (particles suspended in the insulating mineral oil) based on the level of the electrical voltage of the device; degree of polymerization of the insulation paper (cellulose polymer); dibenzyl disulfide content (formation of copper sulfide in windings); partial discharges determined by the acoustic emission method, and analyis of their correlation with the loading. These criteria complement existing studies and express the rigor required to analyze transformer insulation systems, in combination with maintenance engineering criteria, thus modeling the analyses performed by specialists and assisting them in decision-making about possible interventions in these devices, which are essential components of electrical.