This paper focuses on the transient stability of a hydro-turbine governing system with three kinds of tailrace tunnels. As the transfer coefficients change with operation conditions, the dynamic transfer coefficients which can describe the transient characteristics of the hydro-turbine governing system are introduced. Then, the transient stability of the hydro-turbine governing system is analysed. The global bifurcation diagrams for the three kinds of tailrace tunnels are respectively presented to investigate the effects of the tailrace tunnels on the stability of the hydro-turbine governing system. Theoretical analysis which proves the validity of simulation results is provided to explain the effects of the flow inertia and water level fluctuation. The influence of the tailrace tunnel gradient on the transient stability is also studied. More importantly, these methods and research results provide theoretical guidance for the arrangement of the tailrace tunnel and the operation of the hydropower station.

中文翻译：

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具有不同尾水道隧道的水轮机调节系统的暂态稳定性

本文重点研究具有三种尾水道隧道的水轮机调节系统的暂态稳定性。由于传递系数随着工况的变化而变化，引入了能够描述水轮机调节系统瞬态特性的动态传递系数。然后，分析了水轮机调节系统的暂态稳定性。分别给出了三种尾水隧道的全局分叉图，以研究尾水隧道对水轮机调节系统稳定性的影响。理论分析证明了模拟结果的有效性，解释了流动惯性和水位波动的影响。还研究了尾水道隧道梯度对暂态稳定性的影响。