基于频域介电谱法研究甲酸对油纸绝缘水分评估的影响

为了准确评估油纸绝缘中的水分含量,研究小分子酸对油纸绝缘水分评估的影响,文中制备了多组不同水分和甲酸含量的油浸纸试样并利用频域介电谱法对其进行FDS测试,基于此提出表征不同酸性环境下油纸绝缘水分含量的特征参量。研究结果表明:水分会影响小分子酸在油纸间的分布,且随着绝缘纸水分含量和油中甲酸含量的增加,油浸纸试样tanδ频域谱在10?3～101显著增大。相较于无酸环境,甲酸含量的增加使油浸纸试样同一水分含量下的tanδ频域谱发生不同程度的增加,实际测量绝缘纸水分含量时小分子酸的影响不容忽视。提出的油浸纸试样介质损耗因素积分量Stanδ,在不同酸性环境中与水分含量均有良好的指数关系,且随着酸值变化与水分呈现出一定的规律,故可用作表征不同酸性环境下油纸绝缘水分含量的特征参量。

Effect of Formic Acid on the Moisture Evaluation of Oil-paper Insulation Based on Frequency Domain Dielectric Spectroscopy

In order to accurately assess the moisture content in oil-paper insulation and study the effect of small molecule acid on the moisture evaluation of oil-paper insulation,the oil-impregnated paper samples with different moisture and formic acid content are prepared in this paper,and FDS test is carried out on it by using frequency domain dielectric spectroscopy,then on the basis of the spectroscopy a characteristic parameter of the moisture content of oilpaper insulation in different acidic environment is proposed.The research results show that the moisture will affect the distribution of small molecules acid in oil-paper insulation and then with the increase of moisture in paper and formic acid in oil,the tanδ spectroscopy from 10^-3 to 10^1 of oil-impregnated paper samples is significantly increased.Compared to the environment with no acid,the increase of formic acid makes the tanδ spectroscopy of oil-impregnated paper samples in the same moisture content a increase in varying degrees,so the influence of small molecule acid can’t be ignored in the actual measurement of moisture content of oil-paper insulation.The Stanδ of oil-impregnated paper samples,proposed in acidic environment,have a good exponential relationship with moisture content in different acidic environment and show a certain law with moisture with the change of acid content,so it can be used as the characteristic parameters of the moisture of oil-paper insulation in different acidic environment.