Analysis And Diagnostic Method Research On Oil Instability Fault Of Turbo-generator Units

Oil instability is one of the normal faults in the operating and start-stop progcess of turbine-generator. Oil instability contanis the two processes which is oil whirl and oil whip. The vibration fault would threaten the security and stability of the unit, more serious damage is the ruin of unit. The vibriation characteristics, diagnosis technology and treatment measures of oil instability is studied deeply in the paper through analysing oil instability fault cases and combined with the object which is turbine-generator.The paper introduced the principle of bearings and bearings type used in current turbine-generator units usually, and then detailedly analysed the specific reasons generated by the fault, vibration instability phenomenon, vibration instability mechanism and the impact of rotor shaft caused by the fault. By analysing oil instability fault cases vibration characteristics and trend changes about oil instability was summarized and the bearing fault type and fault reasons was analysed statistically. The oil film instability failure diagnosis rules are exported by using Rough Set Theory. Based on the diagnostic rules the oil whip diagnostic program was done. By using analytical method of FTA and FMEA the oil film instability problems are analyzed, combined with the fault diagnosis rules, the secondary fault symptoms and the required monitoring parameters of the fault diagnosis. The oil instability troubleshooting flowchart was obtained. Finally, by using the method of vibration fault diagnosis in the field proposed by the paper, oil instability fault was diagnosed accurately. Meantime, treatment measures are provided, oil instability fault of the unit was resolved. The method may be used on vibration fault diagnosis of oil instability in the field.