Transformers Failures Classification Techniques by High Frequency Current Sensors

• Grant number: 22/08656-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2022
• End date: June 14, 2023
• Field of knowledge: Engineering - Electrical Engineering
• Principal Investigator: Bruno Albuquerque de Castro
• Grantee: João Pedro Gouvêa
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

The interest in tracking systems of transformers has grown significantly in the last few years. This increase comes from researchers and different industrial sectors because detecting a flaw rouses a high level of control in these electrical machines, avoiding damages and allowing economy on maintenance. In the antecedent stages of a breakdown in transformers, it's usual to identify partial discharges or short-circuits incipients that started due to the deterioration of dielectric materials that compose the transformer. Then, the acknowledgment of this phenomenon could indicate isolation conditions and prevent collapses in the electrical machines. Besides that, one of the main subjects to be analyzed is the local where the flaw is happening. For example, the damage could occur in the active part as much as in the isolation of a transformer. It's notable to diagnose these types of flaws because require different actions during maintenance. In this sense, the actual proposal has the objective of applying current sensors of high frequency, known as High Frequency Current Transform (HFCT), with a bandwidth of 50 MHz, to evaluate differences in frequency of current signals resulting from partial discharges in isolators and short circuits incipients that occur on the active part of transformer insulated by oil. From this perspective, a comparative study will be carried out between the Fourier and Wavelet Transforms to evaluate the sensitivity of each Transform for failure classification. Additionally, should be highlighted that the current sensor considered in this scientific research is from an international association between the advisor and the British enterprise IPEC, experts in monitoring medium tension systems.