As for the hydraulic oil cylinder cracking of energy storage mechanism for 500 kV 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.