Research On Vibration Characteristic Of 600MW Steam Turbine Unit Under Different Arc Admission

With the rapid development of Chinese power industry, the time of large units, large power plant, large power grid, UHV transmission is coming and 600 MW and above level have become the main model of the thermal power unit. But because of the enlargement of power grid peak valley difference, the time of a part of units designed based on basic load operating under partial load is increasing. Although the safety of single-valve steam distribution is well, throttling loss is big. Sequence valve steam distribution can improve the thermal efficiency of the unit by decreasing throttling loss, but units are at increased risk for admission of failure. So it is of great significance to research the safety and stability of unites under the condition of partial admission.In this paper, finite element model of the high pressure rotor is established and its model analysis is carried out based on a 600 MW supercritical air-cooling turbo-generator set. Then the high pressure rotor shafting vibration characteristics are researched under different valve management programs. First, the effect of axial impact to shafting vibration characteristics under different valve management programs is researched from the view of time domain and frequency domain. Second, the effect of valve management programs to oil film dynamic characteristics, axis location, shafting stability, clearance of vibration is researched from the radial distribution force produced by partial admission. Then an improved nozzle structure is put forward. Third, shafting vibration caused by valve shake during the single valve sequence valve switch is simulated based on Simulink simulation system and some measures to decrease valve shake are put forward. At last, an improved noise reduction method based on threshold value is put forward and combining with the case of a certain power plant, the admission of failure is analyzed, diagnosed and treated.