在国内首次应用模型水轮发电机组对三峡地下电站变顶高尾水洞方案进行水力过渡过程试验研究。对水轮机导叶实行分段关闭,并求出了二段关闭的最佳拐点,试验证实了二段关闭对减小尾水管进口的负压和机组转速上升有明显的作用。通过有关水力参数的测试,认为变顶高尾水洞可以满足各项技术要求,是一个减少山体开挖、节省投资的新型设计方案。在地下电站中具有广泛的应用前景。

The test tesearch on hydraulic transient process inside the changing topaltitude tailrace tunnel of TGP'sunderground power plant was conducted for the firsttime in our country by use of a model generating set.Adopting the piece wise linear closure for guide vanes of turbine,the best inflection point of twostepclosure (i.e.closed in two kinds of uniform speed)was found,and it was verfiedthat the method of twostep closure has obvious effect for decreasing negative pressures and the rising rates of rotational speed of generating set.Through the measurement of hydraulicparameters,it was regarded that the changing topaltitude tailraee tunnel scheme can meet all the technical reqirements,and it is anewtype design scheme benificial for decreasing rock excavation and saving engineering investment.It can be widely applied in underground plant.
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