Research On Force And Abnormal Vibration Of 1200MW Turbine Generator Rotor

Large turbine generator is the main equipment in power plant,which is driven by the rotating shaft of steam turbine,which is used to convert mechanical energy into electric energy and transmit electric power to the power grid.The rotor of the turbine generator is responsible for transmitting the load torque supplied by the steam turbine.The rotor has high working speed and great mechanical stress due to centrifugal force.At the same time,the rotor has strong magnetic field in operation.The rotor is subjected to great electromagnetic force.Failure in the rotor will not only result in forced shutdown,but also a long overhaul period.Therefore,the strength and force analysis of generator rotor and its structural parts must be accurate,eliminate the hidden trouble of design,and ensure the safe,stable and reliable operation of generator.Firstly,according to the overall structure and force characteristics of 1200 MW large turbine generator rotor,the stress of the rotor shaft neck,tooth and slot wedge,rotor retaining ring and other important parts are analyzed under different working conditions such as rated working condition and short circuit working condition.Based on the derivation and calculation,the strength calculation of gear head wedge,rotor retaining ring and rotor journal of 1200 MW turbine generator rotor is carried out,and the stress situation of each component is analyzed by finite element method,and the calculated stress results are evaluated through the calculation.By comparing the influence of different journal diameter and the corresponding force change of journal chamfer,the structure design of generator rotor is optimized and the safety performance of generator rotor is improved.Based on the force analysis and strength calculation of generator rotor,the critical speed calculation model of 1200 MW turbine generator rotor is established according to the vibration characteristics of generator rotor.The dynamic characteristics of generator rotor and the critical speed of rotor bending vibration and its influencing factors are analyzed and studied by means of finite element tool and relevant theoretical knowledge of rotor dynamics.The influence of gyro effect,oil film stiffness and shaft length on the critical speed is calculated and analyzed.The abnormal vibration of large turbine generator after putting into operation is also listed Some possible causes are given,and the corresponding cause analysis is given,which provides a reference direction for the abnormal vibration problems of large turbine generators.According to the causes of abnormal vibration of generator,this paper studies and deals with the abnormal vibration cases in operation field,puts forward the solution measures and treatment scheme,and verifies the results of the treatment scheme,verifies the accuracy and rationality of rotor force analysis,strength calculation and vibration analysis,and successfully solves the vibration problem.It provides reference and support for dealing with vibration problems of 1200 MW turbine generator.