Abstract
Dry-type insulated transformers stand out for their higher applicability in substations, high-voltage instrumentation systems, and electrical installations. In this machine, the insulation system is constituted of dielectric materials such as epoxy resin and Nomex paper. Some critical issues in the operation of this equipment, such as overload, moisture, or heat, can induce a slow degradation of the physical–chemical properties of the dielectric materials, which can culminate in the total failure of the transformer. However, before the transformer’s shutdown, it is common to detect discharge activity in the insulation system. Based on this issue, this work proposes an experimental and comparative analysis between acoustic emission and Hall-effect sensors, aiming at differentiating discharges in epoxy resin and Nomex paper, materials that constitute the insulation of the dry-type insulated transformers. Two signal processing techniques were studied: traditional frequency analysis and discrete wavelet transform. The objective is to develop signal processing techniques to differentiate each type of discharge since different discharges require different maintenance actions. The results obtained indicate that acoustic emission sensors and Hall sensors are promising in differentiating discharge in epoxy resin and Nomex paper. Furthermore, the pattern recognition tools presented by this work, which associated the wavelet levels energies and the energy of the full signals with the average band and the equivalent bandwidth, were effective to perform feature extraction of power transformer condition.
Highlights
A Comparative Analysis Applied to the Partial Discharges Identification in Dry-Type Transformers by Hall and Acoustic Emission Sensors
This article aims to perform a comparative analysis between acoustic emission and Hall-effect sensors to perform the distinction of epoxy resin and Nomex paper partial discharge activity
It can be observed that the acoustic emission signals from discharges in Nomex paper have small amplitudes concerning epoxy resin
Summary
The transformers can suffer unexpected thermal, mechanical, electrical, and environmental stresses due to overload, moisture, heat, and other critical operational conditions These issues induce a slow degradation of the machine’s insulation, leading the transformer to total failure [3,4,5,6]. PDs are low-energy ionization processes of the dielectric materials that constitute the transformer insulation system (IEC 60270, 2000) [10], such as epoxy resin and Nomex paper [11]. In this sense, the identification of partial discharges is an important indication of the condition of the electrical machine. They produce heat, light, electromagnetic, and acoustic waves, increasing the degradation of the dielectrics [9,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
