Refined Modeling and Dynamic Characteristics of Self-excited Vibration in the Main Inlet Valve of Pumped Storage Power Stations

Abstract

Self-excited vibration of the main inlet valve poses a great threat to the safe operation of the pumped storage power system, thereby making an indirect hazardous effect on the frequency stability of the power grid. In order to avoid self-excited vibration, this paper focuses on the refined modeling and dynamic characteristics of self-excited vibration. Firstly, the flexible valve model is introduced and the refined pumped storage power system modeling considering self-excited vibration is established. The constructed model is then validated by comparing it with field data in the frequency domain. Secondly, the sensitivity of self-excited vibration to system parameters is investigated by using the modified Morris method. Once the sensitive parameters are found, the effect law of these parameters on the dynamic characteristics of self-excited vibration is studied in depth. Finally, engineering advice is proposed. The result indicates that the self-excited vibration is most sensitive to the length of the diversion pipe, valve clearance of the main inlet valve, and water hammer velocity. Moreover, it is verified by simulation that shorter upstream pipe length, lower water hammer velocity and smaller valve clearance help to restrain the amplitude and deterioration rate of self-excited vibration.