典型内部缺陷下GIS盆式绝缘子有限元应力分析

Finite Element Stress Analysis on GIS Basin-type Insulator with Internal Defect

受制作工艺及运行条件影响,GIS盆式绝缘子较易产生气泡、裂缝等典型内部缺陷。采用有限元法对252 k V盆式绝缘子内部存在气泡、裂缝时不同受力状态下的应力进行分析,并与正常情况下绝缘子的应力进行比较。结果表明:对绝缘子凹凸两面同时施加SF6气体压力时,绝缘子的应力最大;绝缘子存在内部缺陷时,应力变化集中在缺陷处;存在气泡时,气泡处应力变化具有波动性,且气泡位于不同位置,应力变化有所不同,气泡位于绝缘子中间部位时应力变化较大;存在裂缝时,裂缝中间部位应力变小,但裂缝两端出现应力奇异性,应力最大值达到正常情况下的9倍左右,且裂缝应力平均值变大。

Bubble and crack defects are easily generated inside basin-type insulators by the effect of man- ufacturing techniques and operating condition. To provide some references to the internal defects detection of insulators, the stress of 252 kV basin-type insulator with bubble or crack defects under different stress states were studied by finite element method, and then was compared with the insulator under normal condition. The results show that the basin-type insulators bear the biggest stress with SF6 pressure on both convex and concave surface. When the insulator exists internal defects, the stress distortion mainly concentrates on the defects. When the insulator exists bubbles, the stress around the bubbles fluctuates; the stress varies with the location of bubbles, and the stress varies obviously when the bubble locates in the middle of insulator, when the insulator exists cracks, the stress in the middle part of crack decreas- es, while both the end of crack show stress singularity, the maximum stress is about 9 times higher than the normal case, and the average stress increases.