油纸绝缘空间电荷特性数值仿真研究

In HV DC area, the distribution and accumulation of space charge in oil impregnated papers is always a very important issue. The distribution of space charge is a main factor leading to discharge which is meaningful in the structure designing process of insulation system. People generally use simulation ways to check the accuracy of the hypothetical theory. Here we introduce and develop a transport model based on effective mobility of the carriers and the trapping level of materials. Two mathmatic models of single-layer samples and double-layer samples under different temperature gradient are then built up to be calculated. By comparing caculation results and experimental results we conclude that our simulation method is reliable. Electrode injection is the main source of space charge. Injected carriers are blocked by the oil paper interface. When the temperature difference and field stress are enhanced, more heterocharge accumulates, resulting in more considerable field distortion. The distortion of electrical field in double-layer samples is more severe in single-layer sample.