The Interaction Effects Between The Torsional Vibration Characteristics Of Hydro Turbine Shaft And Governor Control

The stability of the hydro-generator shafting system is the most important characteristic of the unit stability.Large hydro-generator sets have large geometric dimensions and relatively weaker relative stiffness.Traditionally neglecting the assumption of torsional deformation of shaft systems may lead to large deviations in shaft vibration analysis.The shaft vibration model described by the lagrange function is established and the torsional effect of shafting system is considered.Turbine runner and generator rotor motion equations.By defining the generalized momentum,the two models are constructed as a unified form of first-order differential equations.Taking the unit spindle system as the research object,the resistance torque on the generator rotor and the dynamic torque on the runner of the turbine are used as the link,and the oscillation characteristics of the shaft system under the assumption of the principal axis of the main shaft are taken as reference.The hydraulic system is included and the shaft system is considered.A complete unit simulation operation system including torsional vibration generator equations,shaft torsional oscillation equations,governors,and excitation governors is used to perform discrete system operation using a second-order Runge-Kutta method to simulate actual operating conditions of the unit.Investigate the dynamic response characteristics of the unit's shafting system and the interaction mechanism with the governor under the interaction of hydraulic factors,mechanical factors,and electrical factors,and understand the oscillation characteristics of the unit under actual operating conditions.The optimal design and vibration control of the unit shaft shaft provide the theoretical basis.The main content of the paper is as follows:(1)Construct a first-order torsional vibration model that describes the torsional vibration of the shaft system.Analyze the energy composition of the system,construct the Lagrangian function according to the Lagrange equation,define the generalized momentum,and derive the first order shafting torsional vibration model required for studying the torsional vibration problem.Finally,the shafting torsional vibration model is compared with the shafting transient model(rigid shaft)under large disturbances and the shafting model under steady state.(2)Build unit simulation simulation platform to simulate unit operation.The model is mainly composed of the following components: a single model of single-pipe elastic water under the hydraulic system unified model,the IEEE working group recommended turbine torque model,the turbine equation of the turbine rotor and generator rotor motion equation considering the torsion effect,and the PID adjustment A control system consisting of a speed controller and a PI excitation controller,considering the torsional vibration transient model of the unit shaft during main torsion.(3)Analyse the influence of unbalanced magnetic tension and hydraulic imbalance force on the vibration of the shaft system when using additional torque.According to the force analysis of the shaft of the unit,the unbalanced magnetic force and the hydraulic imbalance force are taken as the additional torque as the alternating torque.Taking into account the unit motion equation and the shaft system torsional vibration model,the external torque is simulated and analyzed at different amplitudes.(4)The analysis of the correlation between the torsional oscillation characteristics of the hydraulic unit and the changes of the governor parameters.Three sets of different governor parameters are given to study the active power of the generator,the relative torsion angle,and the unit shafting along the x-axis and y-axis when the spindle system is in different governor parameters,different adjustment modes(power adjustment,speed adjustment).The oscillating characteristics of the direction;For the same regulation mode,when the fault disturbance occurs in the generator set,the influence of the governor parameter setting on the vibration characteristics of the generator set,different governor settings,different oscillation curves are obtained.