Abstract：In order to explore the influence of servomotors characteristics on the extreme value and time history of volute, draft tube pressure and unit speed in the process of wicket gate closure, a diversion hydropower station in China was taken as the research object to establish the calculation simulation model of hydraulic transition process based on the characteristic line method, and the hysteresis and buffer process in the process of wicket gate closure was considered, then the model was verified combined with the real machine load rejection experimental data.The comparative analysis between the wicket gate closure law considering servomotor charateristics and the generalized broken line closing law and the hysteresis time sensitivity analysis was carried out. The results show that the hysteresis process mainly affects the speed rising rate of the unit. The longer the hysteresis time, the greater the speed rising rate, but has little effect on the time history and extreme value of volute pressure and draft tube pressure. The buffering process has no effect on the extreme value of regulation and maintenance parameters due to its late occurrence time, but has a great impact on the time history of volute pressure and draft tube pressure after the last closing of guide vane. The research results can provide reference for the simulation of guide vane closing law of unit in the hydraulic transition process.
