油纸绝缘频域介电谱归算方法研究

Research on method of frequency normalizing in frequency domain of oil-paper insulation

变压器油浸纸板是其油纸绝缘系统的重要组成部分,其频域介电响应曲线受测试温度、纸板内部含水率的严重影响,为研究不同因素对其归算准确性的影响,首先,在实验室条件下制备多组不同含水率的油浸纸板试样,并针对不同含水率试样进行变温介电谱测试;其次,通过上述测试试验结果,提出基于特征频率点的频谱平移方法,并对不同含水试样的温度介电谱进行平移归算;最后,通过不同含水率油浸纸板频域介电谱平移归算结果发现,不同水分含量油浸纸板的弛豫时间活化能会影响温度介电谱的平移趋势,随着含水率的增加,油浸纸板弛豫时间活化能呈指数增加,因此,为更好地将频谱归算方法与含水率影响激活能量的关系相结合,根据试验结果对油浸纸板的激活能量与含水率进行了定量表征,对提出的平移归算模型进行了进一步完善,并验证了不同含水率下频谱曲线频率归算方法的有效性。

The oil-impregnated pressboard of the transformer is an important part of the oil paper insulation system.The frequency domain dielectric response curve is affected by the test temperature and the internal moisture content of the pressboard.In order to study the influence of different factors on the accuracy of the calculation,a number of oil-impregnated pressboard samples with different moisture content were firstly prepared under the laboratory conditions.Temperature-dependent dielectric spectroscopy test was implemented for samples with different moisture content.Secondly,according to the test results,a spectral translation method based on characteristic frequency points was proposed.The temperature dielectric spectra of different moisture were calculated by translation.At last,based on the frequency domain spectrum translation results of oil-impregnated pressboard with different moisture content,the relaxation time activation energy will affect the shift trend of temperature dielectric spectroscopy.The activation energy of the oil-impregnated pressboard’s relaxation time increases exponentially with the rise of moisture content.To better combine the relationship between the frequency conversion method and the effect of the moisture content on the activation energy,according to the experimental results,the activated energy and moisture content of the oil-impregnated pressboard were quantitatively characterized.The proposed frequency translation model is optimized,and the effectiveness of the optimal translation method is verified.