Study of Bubbles Evolution in Mineral Oil-paper Insulating System under Sudden Changes in Temperature

2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) Pub Date : 2021-12-12 DOI:10.1109/CEIDP50766.2021.9705464

H. Wilhelm, P. Fernandes, L. Dill, K. Moscon, C. Steffens, S. Peres, V. Bender, T. Marchesan, J. B. Ferreira Neto

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引用次数: 1

Abstract

Transformers at nominal operating temperatures present low risk of bubble formation in mineral oil-paper insulating systems. However, in the case of overload with meaning temperature increase, bubble formation risk significantly increases. That is of concern since it can increase partial discharge risk, alter oil dielectric strength and increase insulation thermal degradation around the bubble. Therefore, this study aims to assess dynamics of bubble formation under sudden temperature changes, in an experimental model comprised of mineral insulating oil and thermally upgraded kraft paper. Results show that bubble inception temperature is dependent on paper water content. Water content values above 1% in insulating paper favored bubble formation. Temperature of bubble inception decreased as water content increased, being 55 °C at 2.5% of water and 120 °C at 0.3% of water. Interestingly, abrupt changes in temperature caused bubble appearance in mineral oil-paper insulation system, regardless of paper water content.

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温度突变条件下矿物油-纸绝缘系统气泡演化研究

在标称工作温度下，矿物油-纸绝缘系统中的变压器产生气泡的风险较低。然而，在温度升高的过载情况下，气泡形成的风险显著增加。这是一个值得关注的问题，因为它会增加局部放电的风险，改变油的介电强度，增加气泡周围的绝缘热降解。因此，本研究的目的是在由矿物绝缘油和热升级牛皮纸组成的实验模型中，评估温度突变下气泡形成的动力学。结果表明，气泡形成温度与纸张含水量有关。绝缘纸中水分含量大于1%有利于气泡的形成。气泡形成温度随着含水量的增加而降低，在2.5%的水条件下为55℃，在0.3%的水条件下为120℃。有趣的是，无论纸的含水量如何，温度的突然变化都会导致矿物油-纸绝缘系统出现气泡。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)

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