Tri-post insulators in gas-insulated transmission line (GIL) are usually fabricated with high mass fraction of micron aluminum oxide (Al₂O₃), which will unavoidably settle under the action of gravity during the preparation process and seriously affect the uniformity. A model of filler sedimentation in epoxy resin composite materials was proposed based on the particle size analysis and Stokes' Law. Some scaled tri-post insulators were prepared and tested by slicing. It is determined that the position of density concentration is the lower side of the two lower posts and the upper interface between the insulator and the conductor. The density ranges from 2.144 to 2.346 g/cm³. The dynamic fracture simulation model of insulator was established and it is found that the insulator fracture occurs at the interface of upper post/insert under radial load, which is verified by experiments. By comparing the influence of sprue position on the density distribution, it is found that the uniformity of insulators is increased by 13.7% by forward pouring compared with reverse pouring. This research develops an accurate method for simulating the filler sedimentation and the fracture process in epoxy-based insulators, which is helpful for the improvement of mechanical reliability of GIL.

中文翻译：

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考虑Al2O3沉降的GIL三柱绝缘子不均匀性及动态断裂特性研究

气体绝缘输电线路（GIL）中的三柱绝缘子通常采用高质量分数的微米级氧化铝（Al ₂ O ₃）制作，在制备过程中不可避免地会在重力作用下沉降，严重影响均匀性。基于粒径分析和斯托克斯定律，提出了环氧树脂复合材料中填料沉降模型。通过切片制备并测试了一些按比例缩放的三柱绝缘子。确定密度集中的位置为两个下柱的下侧以及绝缘体与导体之间的上界面。密度范围为2.144至2.346 g/cm ³。建立了绝缘子动态断裂仿真模型，发现在径向载荷作用下，绝缘子断裂发生在上柱/插件界面处，并经实验验证。通过比较浇口位置对密度分布的影响发现，正向浇注比反向浇注绝缘子均匀度提高了13.7%。本研究开发了一种精确模拟环氧绝缘子填料沉降和断裂过程的方法，有助于提高GIL的机械可靠性。