Identification of operational failures in oil-filled transformers by advanced signal processing techniques and piezoelectric transducers

• Grant number: 20/10527-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2021
• End date: August 31, 2021
• Field of knowledge: Engineering - Electrical Engineering
• Principal Investigator: Bruno Albuquerque de Castro
• Grantee: Amanda Binotto
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Monitoring systems capable of providing a reliable diagnosis of the operating condition of high voltage devices, such as power transformers, have growing attention of science and industry. In the stages before to the total failure of the transformer, it is common to detect full or partial discharges. Thus, these phenomena are considered important in indicating the condition of the isolation of the transformer and their diagnosis can anticipate total failures in the device. Although several non-invasive approaches for monitoring discharges have been proposed, the Acoustic Emission has characterized as promising technique due to its low cost and simple applicability. In this methodology, the identification of transformer failures occurs through the application of piezoelectric transducers that sensing the acoustic waves emitted by full or partial discharges. However, there are many scientific and technological challenges in this field. In the current proposal, the objective is to apply digital signal processing techniques to verify the difference between the acoustic emission signals from internal discharges, which occur inside the active part of the transformer, which is immersed in oil, from the external discharges that occur in the transformer bushing. In practical application, each type of failure requires different maintenance actions, and, therefore, their differentiation can be an important improvement for acoustic emission methodology. Besides the scientific contribution of the proposal, the field of this work has international insertion as it will have synergy with the research group of the High Voltage Laboratory at the Technical University Federico de Santa Maria, in Santiago, Chile.