中文摘要：

空间电荷对油纸复合绝缘结构电气性能的影响由于测量上的困难而至今尚未明了,多层复合绝缘结构使得空间电荷特性更加复杂。为此,应用电声脉冲（PEA）方法研究了电压极性对纸-纸和纸-油这2种双层绝缘结构中以及界面处空间电荷特性的影响。研究发现在2种结构的界面处积聚的空间电荷极性与施加电压的极性一致。对2种结构中空间电荷特性进行了比较,结果表明纸-油结构中空间电荷的运动速率比纸-纸结构中慢,并且具有更深的陷阱能级。通过分析认为双层介质界面处存在的势垒导致了界面电荷的积聚,其极性由电极的电荷注入、界面的陷阱、电场和介质的电导等因素协同决定;绝缘材料陷阱能级的不同是造成2种绝缘结构空间电荷运动速率不同的因素之一。

英文摘要：

The effect of space charge on oil-paper insulation is yet not well understood due to the difficulty in measurement, and the structure of multi-layer insulation even makes the space charge characteristics in oil-paper insulation more complex. Therefore, we investigated the space charge dynamics in two double-layer insulation systems under negative and positive voltages. One of the systems was consisted of two oil-paper layers, and the other was consisted of an oil-paper layer and an oil layer. The space charge distribution was measured by the pulsed electroacoustic （PEA） technique. The results showed that the polarity of charge accumulating at the interface was in accordance with the applied voltage in both cases. Moreover, the oil-paper system was compared with the paper- paper system, and it was found that the oil-paper system had a smaller velocity of space charge movement and deeper trap energy than the paper-paper system . Further analyses reveal that the barrier at the interface of double-layer system is the cause of the charge accumulation, and its polarity is determined by three factors together, i.e. the speed and polarity of charge injection at both electrodes, the trap characteristics of the interface, and the electric field and the conductivity performance of the dielectric. The difference of trap energy of dielectrics is one of the factors that cause the difference in the moving speed of space charge in the two insulation systems.