温度特征参数提取及其对油纸绝缘频域谱的影响研究

Extraction of Temperature Characteristic Parameter and Its Effect on Frequency-domain Dielectric Spectroscopy of Oil-paper Insulation

温度是影响介电响应检测结果的重要因素之一,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,在频域介电谱理论的基础上,结合油浸纸板介电响应函数模型对不同温度下实测油浸纸板的频域介电谱进行拟合,并借助有限元仿真方法研究温度对变压器主绝缘结构频域介电谱的影响。结果表明:介电响应函数模型中的特征参数直流电导率σ0和弛豫时间τ与温度的关系满足Arrhenius方程,而温度变化时其他参数基本保持不变;随着温度的升高,油纸绝缘系统的ε′值只在f<1 Hz的中低频段增大,ε″-f曲线整体向高频方向平移,且ε″极小值对应的频率点也向高频方向移动;对于油纸绝缘系统,根据Arrhenius方程通过曲线平移的方法可以较好地消除温度对频域谱测试结果的影响,只在频率f<0.01 Hz的范围内稍有偏差。

Temperature is one of the important influence factors of dielectric response testing result. In order to apply frequency domain dielectric spectroscopy （FDS） to nondestructive testing of oil-paper insulation more effectively, the measured FDS curves of oil-paper insulation at different temperatures were mathematically fitted with dielectric response function model based on FDS theory, and the effect of tem- perature on the FDS of transformer main insulation structure was studied by finite element simulation. The results show that the relationship between DC conductivity （a0） and temperature （T） and the relation- ship between relaxation time （r） and temperature （7） both satisfy the Arrhenius＂ equation, while other parameters basically do not change with temperature. With the increase of temperature, e＇ of oil-paper insulation increases when the frequency is lower than 1 Hz, and the e＂-f curve as well as the minimal value of ε＂ shift to high frequency direction. According to Arrhenius model, the effect of temperature on FDS testing results can be eliminated by curve shifting for oil-paper insulation system, and there is a slight deviation when the frequency is lower than 0.01 Hz.