一起500 kV断路器储能机构液压油缸开裂故障分析

Analysis on Oil Cylinder Cracking of Energy Storage Mechanism for 500 kV Circuit Breaker

文中针对一起500 kV断路器储能机构液压油缸开裂事故,基于外观宏观检查、油缸取样分析、有限元建模仿真、无损CT检测、电镜分析等检测数据,研究该事故发生的主导因素。结果表明,造成断路器储能机构液压油缸开裂的原因为应力腐蚀。造成应力腐蚀开裂的原因是由于阳极化层处理后材料表面硬度显著增大,并且其表面存在Cl、S腐蚀性元素,而开口位置和孔口边沿设计不合理导致存在拉应力,进而在拉应力和化学腐蚀共同作用下出现应力腐蚀现象。最后基于事故原因对制造商提出了相关改善和防范措施。

As for the hydraulic oil cylinder cracking of energy storage mechanism for 500 k V circuit breaker in this paper,the dominant factor of the fault is studied on the basis of such process as appearance of macro inspection,sampling analysis of the oil cylinder,finite element modeling simulation,non-destructive CT testing and electron microscopy analysis.The results show that the cause of the cracking of the hydraulic oil cylinder of the energy storage mechanism for the circuit breaker is stress corrosion.The reason for stress corrosion cracking is that the surface hardness of the material increases significantly after the anodized layer is treated,and such corrosive elements as Cl and S are existed on its surface.The unreasonable design of the opening position and the edge of the orifice leads to the existence of tensile stress,thus occurring stress corrosion under the combined action of chemical corrosion.Finally,relevant improvement and preventive measures were proposed to the manufacturer based on the cause of the accident.