Research On Torsional Vibration Controlling And Protection Method Of Turbo-generator Under Sub-synchronous Oscillation

In the new century, with the sustained growth of China’s economy, industrial and residential electricity consumption is also growing. Stand-alone capacity is also growing, large-scale power grid construction is also growing rapidly, the grid structure becomes more complicated. Complex structure of grid and unit structure makes turbogenerator torsional vibration problems frequent. Severe torsional vibration accident will cause serious damage to the unit and huge economic losses, and even hurt the plant operations personnel safety of life. It also affects the normal operation of generators and power systems. So the research on torsional vibration is very necessary.This paper focuses on the establishment of turbogenerator torsional vibration monitoring, analysis and protection strategy under sub-synchronous oscillation. Firstly, the large turbine generator shaft torsional vibration modeling and the method of torsional vibration inherent characteristic analysis is studied. The paper put forward a method of torsional vibration response analysis under the sub-synchronous oscillation. According to the results of the shaft stress response analysis, estimate the fatigue life loss under shaft torsional vibration and assess safety. Result of the assessment use for torsional vibration alarm and protection threshold setting.Secondly, the paper studies SSO mechanism, features and identification methods. the safety of torsional vibration analysis method simulation, does Simulation of torsional vibration safety analysis. It analyzes the impact of falling load operation on shaft fatigue under sub-synchronous oscillation. According to the simulation results proposed to reduce the shaft damage by lowering load operation, propose different sub-synchronous oscillation Trend of torsional vibration improvements protection threshold.Finally, the article presents online monitoring, suppression and protection strategies on turbogenerator torsional vibration under sub-synchronous oscillation under. It is possible to evaluate the safety of shafting torsional vibration quickly and accurately and avoid the economic loss and interference on the power grid disturbance due to torsional vibration. Finally, on-line monitoring, suppression and protection strategies are raised by simulation. Results of this study can be put into engineering applications.