硅橡胶材料表面电荷消散现象

Surface Charge Decay on Silicone Rubber Materia

研究硅橡胶材料表面电荷消散的规律可为直流绝缘子的设计提供理论依据。为此,利用针-板电极向硅橡胶材料试样表面注入电荷,在不同湿度环境下进行了电荷消散实验。采用电容探头法测得了试样表面电位分布,并反算了电位分布为电荷分布。结果显示:低湿度下试样表面电荷形貌在消散过程中基本不发生改变,电荷呈"同心圆"状分布;靠近电极处带有与所加电压同号的电荷,远离电极处带有与所加电压异号的电荷;高湿度下试样表面电荷形貌在消散过程中发生改变;消散过程近似呈指数衰减且正电荷比负电荷更易消散,消散过程的衰减时间常数τ的数量级为103 s。得出结论:在低湿度下,表面电荷主要向材料内部消散,体电阻率越低,消散速率就越快;随着湿度增加,沿表面消散速率及整体消散速率加快。

The study on the law of surface charge decay of silicone rubber materials may provide a theoretical basis for the design of DC insulators. In our research, sample surfaces are charged by a pair of needle plate electrode, then surface charge decay process is observed under different humidity of air. The surface charge distribution is derived from the measured surface potential distribution which is obtained by capacitance probe method. The results show that the surface charge distribution still maintains its concentric circle distribution during the decay process when the decay process occurs in low humidity air. The polarity of the surface charge near needle electrode is the same as that of the applied voltage, while the polarity of the surface charge far from needle electrode is contrary to that of the applied voltage. The initial surface charge distribution changes its shape when decay process occurs in high humidity air. The decay process of the surface charge is similar to exponential decay process, and the magnitude of the time constant is 103 s. The positive charges are easier to decay than negative charges. It is concluded that the surface charges mainly decay by volume resistivity in low humidity air, and the higher the volume conductivity is, the faster the decay rate will be. As the humidity of the surrounding air becomes higher, the decay rate by surface conductivity as well as the total decay rate grows faster.