Surface Discharge Mechanism on Epoxy Resin in Electronegative Gases and Its Application

Park, Herie; Lim, Dong Young; Bae, Sungwoo

doi:10.3390/app10196673

Cited by 8 publications

(7 citation statements)

References 34 publications

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“…In this context, several works have proposed methodologies to perform the partial discharge detection in epoxy resin and Nomex paper. Park et al (2020) [24] studied the behavior of epoxy discharges in gas-insulated systems such as sulfur hexafluoride. Aakre et al (2019) [7] developed a study related to the unconformities in the resin impregnation process, and proposed an equivalent circuit model to describe the effects of discharges on these materials.…”

Section: Partial Discharges In Dry-type Transformersmentioning

confidence: 99%

“…In the second, piezoelectric transducers capture the acoustic waves emitted by the discharges [21][22][23]. More specifically, in the case of transformers with dry insulation, the failures can occur in the epoxy resin [24], which constitutes the device's external insulation, and it is directly in contact with the environment. On the other hand, PDs can start in the paper that physically insulates the two transformer's windings [25].…”

Section: Introductionmentioning

confidence: 99%

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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: Partial Discharges In Dry-type Transformersmentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…Swelling was conducted by immersing the samples in CH 2 Cl 2 for 24 h before evaluating the swelling ratio (SR) according to Equation (1). After that, the insoluble materials were dried in a vacuum drying oven until constant weight was reached, and the gel fraction (GF) was obtained according to Equation (2): 31 where m 0 is the original weight of the sample, m 1 is the mass of the sample after swelling, and m 2 is the mass of the sample after drying.…”

Section: Chemical Structure Experimentsmentioning

confidence: 99%

Healable epoxy‐based dielectric semi‐interpenetrating networks with different degrees of cross‐linking

Sun

Luo

Zhang

et al. 2021

J of Applied Polymer Sci

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This study concerns thermal stimulated healable epoxy-based semiinterpenetrating networks (semi-IPNs). The crosslinking degree was adjusted using different curing agents to demonstrate its influence on healability. In addition to tensile properties, this study focuses on the influence of healing efficiency on dielectric performance, especially leakage current, following mechanical damage. We propose that there exists an inverse relationship between the degree of crosslinking degree and healing. A maximum healing efficiency of 93% is obtained calculated from volume resistivity change. We find that the variable T g of the semi-IPN crosslinking network based on epoxy resin, rather than the variable T m of the thermoplastic, determines the temperature boundary for healing. We further suggest that the healing efficiency could be influenced simultaneously by the network structure and the quantity of poly(ε-caprolactone). These results suggest that semi-IPNs can be used to develop healable insulating materials for electrical applications.

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“…As electron attachment is more effective than electron ionization from an insulating angle, the use of an electronegative gas is usually sufficient in the design method of insulating systems. Nevertheless, to obtain higher dielectric strength of the insulation, the mentioned electron-swarm parameters cannot be neglected [4,28,29].…”

Section: Electronegative Gases As An Insulating Mediummentioning

confidence: 99%

Study on the Effect of Helium on the Dielectric Strength of Medium-Voltage Vacuum Interrupters

et al. 2021

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This paper presents the results of a comparative analysis of the dielectric strength of disconnecting vacuum interrupters operating on air and helium. The breakdown voltage Ud was measured in the pressure range from 8.0 × 10−4 Pa to 3.0 × 101 Pa for air and from 8.0 × 10−4 Pa to 7.0 × 102 Pa for helium, while varying the interelectrode distance from 1.0 to 5.0 mm. Dedicated laboratory workstations were used to determine the actual pressure values in the vacuum interrupters tested and to precisely measure and record the dielectric strength results of the test object. It was found that the helium-filled vacuum interrupter maintains its full dielectric strength in significantly larger pressure ranges, while the air-filled vacuum interrupter loses its insulating properties. Thus, it is possible to make vacuum interrupters based on the working medium associated with pure helium, with larger working pressure ratings. Under such conditions, it is easier to maintain the tightness of the device and to limit cut-off currents and overvoltages associated with vacuum switchgear.

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Surface Discharge Mechanism on Epoxy Resin in Electronegative Gases and Its Application

Cited by 8 publications

References 34 publications

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

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

Healable epoxy‐based dielectric semi‐interpenetrating networks with different degrees of cross‐linking

Study on the Effect of Helium on the Dielectric Strength of Medium-Voltage Vacuum Interrupters

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