Design of Grading Rings for Air-Core Power Reactors

Salama, Mohamed; Hashad, I.F.M.; Srivastava, K. D.; Hackam, R.

doi:10.1109/tpas.1984.318386

Cited by 4 publications

(1 citation statement)

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“…During the operation of dry-type aircore reactors, if creeping branch discharge occurs, the aging process will be accelerated, and even turn-to-turn short circuits may occur. [19,20] However, the current research lacks the analysis of the flashover voltage change rule of epoxy/glass fiber materials during thermal aging. Therefore, it is urgent to carry out research on the deterioration mechanism of the surface insulation, dielectric, thermal, and mechanical properties of epoxy/glass fiber composites under thermal aging.…”

Section: Introductionmentioning

confidence: 99%

Thermal‐aging characteristics of epoxy/glass fiber composite materials fordry‐typeair‐core reactors

Bian

Xia

et al. 2021

Polymer Composites

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In recent years, dry-type air-core reactors have frequently experienced inter-turn short circuits due to the aging of the inter-turn insulation. In this paper, we prepared epoxy/glass fiber samples and carried out an accelerated thermal aging test up to 840 hours. In different stages of aging, we tested the surface insulation properties, dielectric properties, thermal and mechanical properties of the samples. The results show that: Flashover voltage drops significantly, and when aging for 35 days, it has dropped by 12.4%. This is because aging is accompanied by the conversion of shallow traps to deep traps and the reduction of conductive channels, which slows down the charge dissipation rate and decreases the flashover voltage. Dielectric, thermal, and mechanical properties also show a deteriorating trend. Through the analysis of the changes in thermal and mechanical properties, it is inferred that thermal aging will damage the epoxy matrix more than the glass fiber. In addition, combined with the scanning electron microscope, Fourier transform infrared spectrometer, and X-ray photoelectron spectrometer characterization results, we believed that the main reason for the material deterioration is the detachment of the glass fiber and the break of the long chain of the matrix. This article has certain reference value for the subsequent engineering application and online monitoring of this material.

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Section: Introductionmentioning

confidence: 99%