Assessment of piezoelectric transducers for incipient short-circuits identification and its evolution in power transformers by signal processing techniques

• Grant number: 22/08119-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2022
• End date: June 30, 2023
• Field of knowledge: Engineering - Electrical Engineering
• Principal Investigator: Bruno Albuquerque de Castro
• Grantee: Ana Beatriz Sacco Teopald
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

The anticipative diagnoses of total failures in power transformers are intimately related to the improvement of the quality indexes in the energy supply of the national electric system. In this context, it is common in the stages preceding the total failure of a transformer to have incipient short circuits that are characterized by the insulation degradation between the windings of a power transformer. As discussed, in many cases these short-circuits can aggravate due to the intensification of dielectric degradation. This failure produces acoustic electromagnetic waves, heat, and ultraviolet radiation, factors that contribute to the intensification of the degradation of dielectric materials that make up the insulation machine. Although several non-destructive techniques for monitoring these failures have been proposed, the Acoustic Emission technique stands out due to its low cost and easy applicability. Piezoelectric transducers are coupled to the transformer's wall to identify the acoustic emission produced by these failures. As discussed, in many cases these short-circuits can aggravate due to the intensification of dielectric degradation. Thus, the objective of the current proposal is to compare two types of piezoelectric transducers and to evaluate the sensor's sensitivity for the diagnosis of the evolution of the failure in the study, that in practice these damages need to be monitored to guarantee efficient maintenance. In that sense, applying signal processing techniques will have an important contribution to the evaluation of the used transducer's sensitivity as well as to the methodology for assessing the damage development. It should be also highlighted that, besides the proposal's scientific contribution, the theme of this study will be made in cooperation with the research group of the High Voltage Laboratory at the Federico Santa Maria Technical University, in Santiago, Chile.(AU)