变压器油纸绝缘水分含量和老化程度定量评估研究

Quantitative Evaluation Research on Moisture Content and Aging State of Transformer Oil-paper Insulation

为了分离绝缘纸老化程度和水分对频域介电谱的影响及提高变压器绝缘纸老化程度和水分含量评估精度,文中通过开展加速热老化试验制备了老化程度和含水量均不相同的5组油纸绝缘试样,并对各组试样进行tanδ频谱测试。试验结果表明,在10-3~10-1Hz频段内,tanδ曲线随绝缘纸老化程度增加而上升;在10-3~102Hz频段内tanδ曲线随绝缘纸含水量增大显著上升,在特征频段10-1~102Hz和10-3~10-1Hz内求取tanδ曲线对频率的积分值Sm和SDP分别作为表征水分含量和老化程度的特征量,并分别给出了特征量与绝缘纸水分含量(Kw)和聚合度(DP)之间的拟合关系。对比分析相同老化程度下水分含量不同的多组油纸绝缘试样的介损频谱特性表明,绝缘纸含水量对特征量SDP影响极大,为此提出了水分补偿因子以量化绝缘纸含水量对老化评估的影响,并进一步提出了全面考虑水分影响的老化程度评估新方法。

In order to distinguish the influence of aging state and moisture on frequency domain spectroscopy and improve the accuracy of assessing aging state and moisture content of oil-paper insulation, in this paper, through conducting accelerated thermal aging experiment, five groups of oil-paper insulation samples with different aging state and moisture content are prepared, and then the tan6 spectrum for each group of specimens is performed test. The testing results show that in the bands of 10^-3~10^-1 Hz, the tan6 value increases with aging degree, while in the band of 10^-3~10^2 Hz, the tan6 value significantly increases with moisture content, obtains the integral value of S. and SDp to tar~ curve in feature band of 10^-1-10^2 Hz and 10^-3-10^-1 Hz as characteristic parameters to assess moisture content and aging state, and establishes quantitative relationship among characteristic parameters moisture content （Kw） and degree of polymerization （DP）. Through comparing and analyzing the dielectric loss spectrum, the result show that the moisture content in insulating paper had great influence on characteristic parameters Spy. Therefore, in this paper proposes moisture compensation factor to quantitatively analyze the influence of the moisture content to aging assessment, and further puts forward the new method to assess the aging state of oil-paper insulation which comprehensively considering the influence of moisture content in insulating paper.