Contribuições à avaliação da degradação da isolação de cabos por meio da análise de descargas parciais

Abstract

The monitoring and diagnosis of the condition of power cable insulation is part of the preventive and predictive maintenance methodology. In this perspective, the detection and analysis of partial discharges is a tool of great importance for the evaluation of the insulation of medium and high voltage cables. In this way, the work presents an literature review involving the themes related to the use of partial discharges in the diagnosis of insulated cables, such as the methods of discharge detection, methods of defect location, signal processing, the behavior of the characteristics of partial discharge pulses and the techniques of application of discharges in cable diagnosis, the main ones being based on the evaluation of the level of apparent discharge measured in picoCoulombs (pC). This said, it was possible to observe several deficiencies in the diagnostic methodologies studied, such deficiencies that can promote inaccurate or even false diagnoses and consequently provide room for the occurrence of unexpected faults in the system. In order to minimize this adversity, a diagnosis methodology is proposed that seeks to incorporate the evaluation of several characteristics of partial discharges together with the apparent discharge, with the possibility of combination with other diagnosis methods such as the Delta Tangent method. For this, a Decision Making Support System. For this, a Decision Making Support System (DSS) was used, based on a scoring system, in which the analyzed characteristics have specific weights that determine their influence on the diagnosis.