为了将频域介电谱法更好地应用于油纸复合绝缘状态无损检测,该文在对电介质物理深入研究的基础上,提出油浸纸板介电响应函数模型,并对实测油浸纸板频域谱进行拟合,提取了函数模型的特征参数,借助有限元仿真研究了老化和水分对变压器主绝缘频域谱的影响。研究表明,实测复介电常数ε*-f曲线与基于油浸纸板介电响应函数的拟合曲线在整个频段内具有良好的一致性;介电响应函数模型中的参数直流电导率σ0能够表征油浸纸板中的含水量m,σ0与m之间具有指数关系;参数α、β以及τ能够表征油浸纸板老化程度,其中,参数α和τ与老化时间t之间存在线性关系,而参数β与老化时间t之间具有指数关系;随着油浸纸板含水量的增加,油纸绝缘系统ε''值在全频段都增大,而随着纸板老化程度加深,ε''值只有在f〈0.01 Hz和1Hz范围内增大。
In order to evaluate the oil-paper insulation's condition more reliably and effectually by using frequency-domain dielectric spectroscopy(FDS) as a nondestructive test, a dielectric response function model was presented based on dielectric physics in depth study. With this proposed model, the actual FDS curves could be mathematically fitted with high accuracy and some characteristic parameters were extracted. After that, the effect of ageing conditions and the moisture content in paper on FDS characteristics of oil-paper insulation systems were also analyzed by finite element method(FEM) approach. These results indicate that the reconstructed ε*-f curve is in good agreement with the measured curve. The characteristic parameter, DC conductivity σ0, can be used to describe the moisture content of oil-immersed paper quantitatively. The relationship between the σ0 and the moisture content is exponentially correlative. The characteristic parameters α、βand τ can be used to describe the aging status of oil-immersed paper quantitatively. There is a linear correlative relationship between α and aging time t and between τ and t. The relationship between β and t is exponentially correlative. With the increase of moisture in paper, ?'' increases in the whole frequency domain. As the aging proceeds, ?'' increases in frequencies of f〈0.01 Hz and 1 Hz〈f〈100 Hz.