抽水蓄能电站水力-机械系统自激振动特性研究

针对部分抽水蓄能电站运行过程中出现的水力-机械振动以及运行不稳定现象,从水力阻抗的角度研究可逆式机组可能产生自激振动的判别条件以及相应的不稳定区域。应用非线性振动理论,分析抽水蓄能电站产生自激振动时的幅频特性。结合具体算例,考虑可逆式机组在不稳定区域("S"形特性区)运行时,进行水力-机械系统的自由振动分析,在全频域范围内分析系统的振动特性,得出相应衰减因子为正的振动模式,同时结合特征线法在时域内进行自激振动分析,给出相应的振动曲线。研究结果表明抽水蓄能电站自激振动由多个衰减因子为正的振动模式叠加而成,其最大幅值与理论分析一致。

Study on self-excited vibration of hydro-mechanical system in pumped storage plants

In order to analyze the hydro-mechanical vibration and the accompanied unsteady running in some pumped storage plants,a study on determining the criterion of self-excited vibration and the corresponding unsteady region has been conducted from the viewpoint of hydraulic resistance.The amplitude-frequency characteristics of self-excited vibration are analyzed by nonlinear vibration theory.In line with a case study,the analysis of free hydro-mechanical vibration for a reversible pump-turbine unit running in the unsteady region(S-shape characteristic region) is made for the whole frequency domain and the oscillating curve is presented by using characteristic method in time domain.It shows that the self-excited vibration of pumped-storage plants is comprised of several vibration modes with positive attenuation factor and its maximum amplitude is identical with theoretical analysis.