变速机组对电站输水系统水力振荡影响研究OA

Due to the wide-range speed regulation capability,variable-speed pumped storage units face more complex hydraulic oscillation situations than fixed-speed ones in water conveyance systems.To un-ravel the underlying influence mechanism,a hydraulic oscillation analysis model tailored for variable-speed pumped storage power stations was developed by integrating the efficiency-optimal speed optimiza-tion strategy with the global matrix method.The impacts of fixed-speed and variable-speed units on the free and forced oscillations of water conveyance systems were compared,and the variation pattern of pres-sure amplitude during the speed regulation process was investigated.The results indicate that variable-speed units can reduce the self-oscillation damping factors of water conveyance systems and enhance sys-tem stability.Under the disturbance of tailwater vortex bands,the pressure amplitude and flow amplitude along the variable-speed units are both lower than those of fixed-speed units.When the rotational speed decreases from the rated speed to 0.9 times,the system oscillation amplitude increases significantly,with the maximum pressure amplitudes of the unit and tailwater tunnel increasing by 6.21%-17.51%and 7.27%-29.17%,respectively.The research findings can provide a theoretical basis for hydraulic oscil-lation analysis and operation optimization of variable-speed pumped storage power stations.