上游串联双调压室可以作为超长引水隧洞水电站的重要的、可行的平压措施,本文开展了带此种平压措施的水电站水力-调速系统的稳定性的研究。首先建立了包括引水管道、调压室、水轮机、调速器、发电机等子系统的完整的水力-调速系统数学模型,推导出描述其系统动态特性的综合传递函数与自由运动方程,然后利用系统的稳定条件绘制稳定域的方式,分析了调压室面积和引水管道水流惯性对系统稳定性的影响。得到:上游串联双调压室水力-调速系统稳定域达到与只设置一个调压室系统相同稳定域时,双调压室的临界稳定断面积之和大于设置单调压室时所对应的稳定断面积;第二调压室(靠厂房)的面积越小,达到相同稳定域时两调压室的临界稳定断面积之和越大;两调压室之间管道的水流惯性占第二调压室上游段管道总水流惯性的比例越小,达到相同稳定域时,两调压室的临界稳定断面积之和与设置单调压室系统的临界稳定断面之差就越小。
Installation of two upstream series surge chambers is a significant and feasible measure for peak pressure control. This paper presents a study on the stability of waterpower-speed control system for hydropower station with such a measure. For this system, we developed a complete mathematical model including diversion pipeline, surge chamber, hydraulic turbine, speed governor, and generators, and derived a comprehensive transfer function and linear homogeneous differential equation that describe the system's dynamic characteristics. The effects of fluid inertia in water diversion system and the surge chamber parameters on stability conditions are also analyzed in this paper using stability domains. The main conclusions are as follows. When the control system reaches the same stability domain as that with one upstream surge chamber, the total cross-sectional area of the two chambers is greater than that of one chamber. If the second chamber or the one closer to the plant is smaller, a greater total area is required to reach the same stability domain. The smaller the ratio of pipe flow water inertia between the two chambers over that between the pipe intake and second chamber, the smaller the difference between the total cross-sectional area of two chambers and that of one chamber system.