变压器油纸绝缘系统低频介电参数方程

摘要

油纸绝缘系统频域介电谱的低频部分更有利于诊断、评估绝缘系统的老化状态与水分含量,为了将频域介电响应法更好地应用到工程中,针对变压器油纸绝缘系统低频激励下的介电响应进行了研究.首先分析了绝缘电介质(油隙、油浸纸)在低频激励下的电极极化过程,进而提出以电导率、离子迁移率等为参量的绝缘电介质的介电参数方程;然后基于变压器油纸绝缘系统的XY几何等效模型,构建变压器油纸绝缘系统低频介电参数方程;最后通过试验对所构建的介电参数方程进行验证.研究结果表明:油纸绝缘系统介电参数计算值与试验值相符合,建立的介电参数方程能够有效地表征变压器油纸绝缘系统频域介电响应低频部分的介电参数.%Frequency domain dielectric response method has been one of the most effective approaches for the condition assessment of oil-paper insulation,and the low frequency part of the response is more effective for diagnosing the moisture content and aging status of oil-paper insulation.To facilitate the using of frequency dielectric domain dielectric response in engineering,the low frequency part dielectric response of oil-paper insulation system was studied in this paper.First,the electrode polarization of insulation dielectrics (oil-gap and oil-immersed paper) was analyzed when it is applied with low frequency excitations.Then,the complex relative permittivity expressions of insulation dielectric were obtained based on conductivity,ionic mobility and other parameters.On the basis of the geometric equivalent model (XY model) of oil-paper insulation system,the complex relative permittivity expressions of oil-paper insulation system for low frequency were obtained.Finally,the validity of established expressions about dielectric constants were testified by comparing the simulated and measured results.The results show that:the calculated complex relative permittivity can fit the measured results well,and the established expressions can effectively express the low frequency part dielectric response of oil-paper insulation system.