在某500 kV变电站运行过程中,其悬式瓷绝缘子发生断裂。采用宏观观察、渗透检测、扫描电镜及能谱分析等方法对该悬式瓷绝缘子断裂的原因进行分析。结果表明:该悬式瓷绝缘子瓷件本体存在夹杂、裂纹缺陷,且瓷件和铁帽胶合部位发生开裂;在长期露天环境下运行,受环境和载荷等外在因素的影响,水分子通过胶合开裂部位进入瓷体,引起瓷体发热,瓷件内部的热效应作用诱导裂纹加速扩展,瓷件强度显著下降,最终瓷绝缘子在应力最为集中的颈部位置发生断裂。

The suspension porcelain insulator of a 500 kV substation broke during operation. The fracture reasons of the suspension porcelain insulator were analyzed by means of macroscopic observation, penetration test, scanning electron microscope and energy spectrum analysis. The results show that the porcelain body of the suspension porcelain insulator had the defects of inclusions and cracks, the gluing part of the porcelain part and the iron cap was cracked. Operating in long-term outdoor environment offected by external factors such as environment and load, the water molecules entered the porcelain body through the glue cracking part, causing the porcelain body to heat. The thermal effect inside the porcelain part induced the cracks to accelerate the expansion and the strength of the porcelain part was significantly reduced. Finally, the porcelain insulator broke at the neck where the stress was most concentrated.