Research on Thermal Aging Characteristics of Dry-type Transformer Epoxy Resin Based on Dielectric Response and Activation Energy

Feng, Jindong; Zhang, X.; Wang, W.; Zhang, W.; Ren, Peng; Peng, Pan

doi:10.1109/ceidp47102.2019.9009940

Cited by 2 publications

(1 citation statement)

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“…In stages preceding total failure, it is usual to detect partial discharges (PDs) activity [9]. 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.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Analysis Applied to the Partial Discharges Identification in Dry-Type Transformers by Hall and Acoustic Emission Sensors

Castro

Santos

Lucas

et al. 2022

Sensors

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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.

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Section: Introductionmentioning

confidence: 99%