特高压直流穿墙套管绝缘支柱在高地震烈度下的机械应力仿真

Mechanical Stress Simulation of Post-insulator in UHVDC Wall Bushing Under High Intensity Earthquake

特高压直流穿墙套管由于其结构细长,在地震中极易受损,然而其内部支柱绝缘子的受力情况未见报道。此外,新型陶瓷材料作为高机械强度的绝缘材料,具备替代环氧材料的应用潜力。为此,该文首先设计了3种基本形状的陶瓷绝缘支柱。其次,通过有限元法计算了9级地震烈度下纯SF_(6)气体绝缘直流穿墙套管中绝缘支柱的应力分布,基于静力法分析了绝缘支柱的受力情况。最后,对比了新型陶瓷支柱与现有环氧支柱的裕度。结果表明:陶瓷支柱中凹线形结构的应力最小,分布最均匀。应力主要在顶部和底部金属嵌件附近的圆弧位置处集中,分别由竖直方向和水平方向的载荷引起,最大应力为105.1 MPa。由于新型陶瓷材料具备了优异的机械强度,地震工况下陶瓷支柱的裕度显著大于环氧支柱,为2.85。因此,相比于环氧支柱,陶瓷支柱可以提供更好的机械支撑,可以为高烈度地震区中SF_(6)气体绝缘设备内部的绝缘支柱的选择和研制提供参考。

UHVDC wall bushing is easy to be damaged in an earthquake due to its slender structure.However,the stress of the inner post-insulator has not been reported.In addition,the new ceramic insulating material has the potential to replace the epoxy materials because of its high mechanical strength.For this,three basic shapes of ceramic post-insulator are designed firstly in this paper.Secondly,the stress distribution of the post-insulator in the pure SF_(6) gas-insulated DC wall bushing under the earthquake with magnitude 9 is calculated by the finite element method,and its stress condition is also analyzed based on the static method.Finally,the margin of the new ceramic post-insulator is compared with that of the existing epoxy post-insulator.The results show that the post-insulator with a concave structure has the smallest stress with the most uniform distributions.The stress is mainly concentrated at the circular position near the top and the bottom metal inserts,caused by the vertical and the horizontal loads respectively with the maximum stress 105.1 MPa.Due to the excellent mechanical strength of the new ceramic material,the margin of the ceramic post-insulator,which is 2.85,is significantly higher than that of the epoxy post-insulator.Therefore,compared with the epoxy one,the ceramic post-insulator has a better mechanical support,which provides a reference for the selection and development of the post-insulators of the SF_(6) gas-insulated equipment in districts with high earthquake intensity.