水轮机导叶关闭规律对蜗壳末端压力的影响

抽水蓄能机组由于S特性,在甩负荷过程中会产生很大的水击压力和脉动压力。为控制压力脉动,以我国某抽水蓄能电站为例进行数值模拟,分析了考虑S特性和脉动压力的两段式和三段式关闭规律的优化方法及在控制蜗壳末端压力方面的优势。结果表明,考虑S特性时,先延时后关闭的两段式关闭规律可有效控制水击压力,其折点时间为工况点到达下奇点时,且第二段快关。考虑脉动压力时,采用先部分关导叶减小开度,而后延时或开启,最后导叶快关的方式可减小脉动压力的影响,三段式关闭规律的两个折点时间分别为工况点到达上下奇点时。相较两段式关闭规律,先关闭后开启再关闭的三段式关闭规律不仅可有效控制脉动压力,在控制水击压力方面也有一定优势。研究成果可为抽水蓄能电站的运维和管理工作提供参考。

Influence of Closing Rule of Turbine Guide Vane on Pressures at the Ends of Spiral Case

Due to the S-shaped characteristics of the pump-turbines, a pumped-storage station can result in relatively large water hammer and pulsating pressures during the load rejection. In order to control the pressure pulsation, a pumped storage power station of China was taken as an example for numerical simulation. And then this paper analyzed the optimization methods and advantages of controlling the pressure at the ends of spiral case for two-stage and three-stage closure laws when considering S-shaped characteristics and plusating pressures. The results show that when considering the S-shaped characteristics, the first two-stage shutting off after a delay law can effectively control the water hammer pressure. The turning point time is that the working point reaches the singular point and the second segment is quick closed. Considering the pulsating pressure, the first part of the guide vane is closed to reduce the opening, and then delay or open, finally the guide vane is closed quickly, which can reduce the impact of pulsating pressure. The two turning points time of the three-stage closure are working points reaching the upper and lower singular points. Compared with the two-stage closure law, the three-stage closure law of the first turning off and then opening followed turning off can not only effectively control the pulsating pressure, but also has certain advantages in control of water hammer. The research results can provide reference for the operation, maintenance and management of pumped storage power station.