沿面闪络用非介入式表面电位测量研究

沿面闪络严重威胁气体绝缘封闭开关(GIS)的安全运行。文中通过对指形电极沿面闪络装置进行非介入式表面电位测量及仿真，在仿真参数设定下，非介入式测量误差仅为2.42%。利用该实验装置对添加纳米SiO₂质量分数为2%的环氧试样进行表面电位测量，升压速率为0.5 kV/5 min。当施加电压不足以引发沿面闪络时，纳米颗粒的添加引起的Maxwell-Wagner界面极化使得表面电位呈现衰减现象。当施加电压接近闪络电压时，表面电位衰减过程出现周期性回升现象，且回升现象出现的频率随施加电压升高而变快，闪络前表面电位衰减过程中的回升现象能够预测闪络的发生。持续性闪络阶段表面电位的幅值波动相较于间歇性闪络要小且相邻闪络间期变短，闪络剧烈。该现象与闪络引起表面灼烧通路更易于发生沿面闪络有关。直流闪络的表面电位测量对闪络预防以及闪络严重性评估具有指导意义。

Non-invasive surface potential measurement of surface flashover

Surface flashover is an important accident threating the safe operation of gas-insulated switchgear (GIS). Non-invasive surface potential measurement for flashover test device with finger-shape electrodes is proposed,and the feasibility of this device is analyzed by finite element software. The results show that non-invasive measurement error is 2.42% under simulation parameter settings in this paper. Surface potential of epoxy with nano-SiO₂ mass fraction of 2% is measured using this device and the ascending applied voltage step is 0.5 kV/5 min. When the applied voltage is unable to induce flashover phenomenon,Maxwell-Wagner interface polarization caused by nanoparticle addition causes surface potential decay process. When the applied voltage approaches flashover voltage,surface potential presents periodic rise phenomenon in the decay process and the frequency of rise phenomenon becomes faster as the applied voltage higher. Periodic rise phenomenon in surface potential decay process before flashover can be used as a signal for predicting surface flashover. Fluctuation of surface potential in the continuous flashover process is smaller than that of intermittent flashover and the interval between adjacent flashover becomes shorter,which is related to the fact that surface burning path in the continuous flashover is prone to flashover. Surface potential measurement of DC flashover provides guidance for flashover prevention and flashover severity evaluation.