应用极化/去极化电流法评估变压器油纸绝缘水分含量

时域介质响应法作为评估变压器绝缘状态的新方法,目前尚无公认的时域特征量能很好地表征油纸绝缘的极化特性。基于极化/去极化电流法提出了新的时域介质响应法的特征量--极化电导率,建立了时域电导模型。搭建了油纸绝缘极化电导率的实验平台,测试了不同温度和水分条件下油纸绝缘的极化电导率并应用最小二乘法对时域电导模型参数进行了拟合。实验结果表明:极化电导率随温度和水分的增加而增大,时域电导模型能较好地反映油纸绝缘在不同温度和水分条件下的极化特性。根据时域电导模型参数直流电导率提出了评估油纸绝缘水分含量的方法并进行了验证,为诊断变压器油纸绝缘水分含量提供了有益参考。

Using Polarization/Depolarization Current Methods to Estimate Oil Paper Insulation Moisture Humidity of the Transformer

Time domain dielectric response method is a new way to assess oil paper insulation state, and there is still no universally accepted parameter to characterize the polarization characteristics of oil paper insulation. A new parameter called polarization conductivity based on polarization and depolarization current method was proposed to model the oil-paper insulation. An experimental system was designed to measure the polarization conductivity of oil-paper insulation at different temperatures and different moisture contents, and the parameters are fitted by least squares method. The result show that with the increase of temperature and moisture content, the polarization conductivity increases, and the time domain conductivity model can well characterize the polarization characteristics of the oil-paper insulation. The method for assessing moisture content of oil paper insulation is put forward and verified, providing a useful reference for diagnosing moisture content of oil paper insulation.