水利水电技术（中英文）

水轮机尾水管压力脉动是水力发电机组出力摆动的重要原因之一,表现为发电机转子角或输出功率的强迫振荡。尾水管压力脉动主要是由尾水涡带造成的,其频率与水轮机转动频率近似成比例。而且,空蚀会加大脉振的强度。单机无穷大系统中,强迫振荡包括暂态和稳态振荡两部分,暂态分量主要与系统的阻尼有关,而稳态分量则主要与干扰信号有关。建立了水机电一体化仿真模型,通过对部分负荷工况下的仿真,分析了尾水管压力脉动对系统阻尼及振荡特性的影响。

The pressure fluctuation in the draft tube of hydraulic turbine is one of the important reasons to lead to the power swing in hydraulic generation unit,which presents as a forced oscillation of rotor angle or output power of generator.The pressure fluctuation in the draft tube is mainly caused by the vortex flow in the draft tube and its frequency is nearly proportional to that of the rotation frequency of the hydraulic turbine.Furthermore,the cavitation could increase the magnitude of pressure fluctuation.The forced oscillation includes transient oscillation and stable oscillation in a single-machine-infinite system,of which the transient component is mainly related to the damp of the system and the stable component is concerned with the disturbance signal respectively.A simulation model for the integrated hydraulic,machinery and electric power system is established herein,with which effect of pressure fluctuation in hydraulic turbine draft tube on the damping and oscillation characteristics of the system is analyzed through the simulation on the part-load operating condition of the system concerned.