Research On Dynamic Characteristics Of Shafting System Of Large Turbine Generator Set With Single Supports

The single-support shafting system is an advanced design concept,and has many advantages compared with the double-supported shafting system.This paper takes the single-support 1000 MW steam turbine generator set designed by STC and Siemens as the research object,which represents one of the world's most advanced set,and studies the dynamic characteristics of the single-support large-scale turbo generator shafting.A static analysis calculation model for the shafting of steam turbine generator sets was established,and a MATLAB program based on this was developed.It is applied to the 1000 MW single-supported steam turbine generator set designed by STC and Siemens.The installation elevation,the lift curve and the bearing load are calculated.The results are close to the Siemens design values.The Dongfang-Hitachi 1000 MW double-supported shafting model was established.The sensitivity of the bearing load to the elevation change in the two supporting modes was compared.It was found that the bearing load of the single supported shaft system is less affected by the change of the elevation compared with the double supported shaft system;Based on the field measurement method of bearing loads of turbo generator set based on strain electric measurement technology,the bearing load test of two STC-Siemens 1000 MW units of a power plant was carried out.The bearing load distribution state was evaluated based on the test results.The vibration,bushing temperature and shaft center position of the #1 machine were tested.The test results show that the load of #7 bearing is too high,which is consistent with the test result of the bearing load;The calculation model of the unbalanced response of the turbo-generator shaft system is established.The unbalanced response of the Siemens 1000 MW single-supported steam turbine generator set during the speed increase process is calculated.The critical speed is close to the Siemens design value and the measured value.The shaft center space curve is used to visually show the unbalanced response coupling characteristics of the single/double supported shaft system at the working speed.The degree of unbalanced response coupling of the single/double supported shaft system is quantitatively compared.It is found that the coupling degree between single-supported shafting rotors is larger than that of double-supported shafting.The influence of elevation variation on the coupling degree of shafting vibration and unbalance response is analyzed.The research shows that compared with the double supported shaft system,the single support shaft system elevation adjustment has less influence on the shafting vibration;properly raising the specific bearing elevation in the project can weaken the mutual coupling between the rotors of the turbine generator shaft system.