Exploration on breakdown mechanism of oil-pressboard insulation under polarity reversal voltage

被引：0

作者：

Wang, Yonghong ^{[1
]}

Gao, Ziwei ^{[2
]}

Zhu, Xuecheng ^{[2
]}

Nie, Hongyan ^{[1
]}

Chi, Minghe ^{[1
]}

Chen, Qingguo ^{[1
]}

机构：

[1] Electrical & Electronic Engineering College, Harbin University of Science and Technology, Harbin, 150080, Heilongjiang Province

[2] Heilongjiang Electric Power Research Institute, Harbin, 150030, Heilongjiang Province

来源：

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | 2015年 / 35卷 / 21期

关键词：

Breakdown mechanism; Converter transformer; Oil-pressboard insulation; Polarity reversal;

D O I：

10.13334/j.0258-8013.pcsee.2015.21.032

中图分类号：

学科分类号：

摘要：

In order to solve the breakdown problem that the main insulation on valve side of the converter transformer face, the breakdown mechanism of the oil-pressboard insulation under the polarity reversal voltage was explored. Using a pair of plate electrode models, breakdown voltage experiments on three kinds of samples such as the oil-gap, the oil immersed pressboard and the oil-pressboard insulation were carried out under the polarity reversal, the step DC and the slowly increasing DC voltage. Currents of three kinds of samples under the polarity reversal voltage were measured. Based on these, the equivalent circuit of the oil-pressboard insulation was determined. The voltage equation was established and the voltage distribution was numerically analyzed. Research results indicate that, the breakdown voltage of the oil-gap apparently decreases with the increase of the voltage application time, but the breakdown voltage of the oil immersed pressboard has little change. The oil-gap sample is not broken down during the polarity reversal. All of the oil immersed pressboard samples and the oil-pressboard insulation samples are broken down during the polarity reversal, so the polarity reversal causes decrease of the breakdown voltage. The insulation resistance of the transformer oil which is calculated by the insulation current is nonlinearity. It will decrease with the increase of the electric field strength and with the increase of the application time in the transient. The insulation resistance of the oil immersed pressboard which is calculated by the residual current is in line with the ohm's law. During the polarity reversal, the voltage on the oil-gap of the oil-pressboard insulation which is affected by the nonlinearity of the transformer oil insulation resistance can keep a high level after a rapid reversal, this calculated value coincides with the breakdown voltage result of the transformer oil-gap. © 2015 Chinese Society for Electrical Engineering.

引用

页码：5656 / 5666

页数：10

共 21 条

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