This study investigates the effect of moisture content on space charge characteristics based on the dynamic space charge response and conductivity characteristics of oilpaper insulation under a DC electric field. Moisture contents ranging from 0.34–2.89% are considered under an electric field of up to 20 kV/mm. The results show that homocharge accumulates inside the oil-paper insulator near both electrodes, with the amount of charge gradually increasing as the moisture content rises. It may be related to the decreased charge injection barrier at the electrode-sample interface as the moisture level increases. The conductivity increases with the rise in moisture level. However, as the conductivity increases, the corresponding space charge accumulation during polarization does not decrease, but increases significantly. This indicates that space charge accumulation may be related to both charge injection and conductivity. The electric field distortion inside the oil-paper insulator increases as the moisture content rises, with the maximum electric field distortion rate going from 16.9 to 92.9% at 5 kV/mm and from 29.7 to 62.5% at 20 kV/mm.

中文翻译：

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含水量对直流电场下油纸绝缘空间电荷行为的影响

本研究基于油纸绝缘在直流电场下的动态空间电荷响应和电导率特性，研究水分含量对空间电荷特性的影响。在高达 20 kV/mm 的电场下，水分含量范围为 0.34-2.89%。结果表明，同电荷在靠近两个电极的油纸绝缘体内部积累，随着水分含量的增加，电荷量逐渐增加。这可能与随着水分含量的增加，电极-样品界面处的电荷注入势垒降低有关。电导率随着水分含量的增加而增加。然而，随着电导率的增加，极化过程中相应的空间电荷积累并没有减少，而是显着增加。这表明空间电荷积累可能与电荷注入和电导率有关。油纸绝缘子内部的电场畸变随着含水量的增加而增大，最大电场畸变率为5 kV/mm时的16.9%～92.9%，20 kV/mm时的29.7～62.5%。