瀑布沟水电站高负荷区异常压力脉动分析

Analysis on abnormal pressure fluctuation in high load area of Pubugou Hydropower Station

瀑布沟水电站2号和4号水轮机相继发现在接近额定出力时,其尾水管、无叶区、蜗壳进口有异常的压力脉动,且幅值较大,限制了机组运行在高负荷区时的实际出力,同时也严重影响到了电站的正常电力生产。为此,对尾水管压力脉动的幅值和频谱开展了分析,根据分析结果,确定了该异常压力脉动的共振特性。在此基础上,对引水管路和尾水管中的水、气两相流体的固有频率进行了测试和计算。计算结果进一步确定了共振主体为引水管路的水体,而引起该压力脉动的激励源则为尾水管的同步压力脉动。最后针对计算结果探讨并提出了解决这种异常压力脉动不利影响的措施。实践表明:制定的措施是适宜和有效的。研究成果可为今后类似问题的解决提供参考与借鉴。

Abnormal pressure pulsations emerged at draft tube,vaneless area and volute inlet of No.2 and No.4 turbines of Pubugou Hydropower Station when the turbines were close to the rated output,and the amplitude was larger.This phenomenon limited the turbine actual output in high load area and seriously affected the normal power production of the power station.Based on the analysis of amplitude and frequency spectrum of the pressure fluctuation in draft tube,the resonance characteristics of abnormal pressure fluctuation were determined.Based on the natural frequency measurement and calculation of water-gas two-phase fluid in draft tube,the main body of resonance was determined as water body in draft tube,and the excitation source was synchronous pressure fluctuation in draft tube.Finally,the solution to the abnormal pressure was discussed.Measures for adverse effects of force pulsation were provided.