水电站多机共用尾水系统并网运行稳定性及动态特性分析  

Stability and dynamic characteristics analysis of grid-connected multiple units-shared tailwater system in hydropower station

作　　者：时有松 张舸[1] 程建[1] 张东峰[1] 李银斌[1] 赵志高 郑阳 SHI Yousong;ZHANG Ge;CHENG Jian;ZHANG Dongfeng;LI Yinbin;ZHAO Zhigao;ZHENG Yang(Baihetan Hydropower Plant,China Yangtze Power Co.,LTD.,Liangshan,Sichuan 615400,China;School of Water Resources and Hydropower Engineering,Wuhan University,Wuhan 430072,China;School of Power and Mechanical Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]中国长江电力股份有限公司白鹤滩水力发电厂,四川凉山615400 [2]武汉大学水利水电学院,武汉430072 [3]武汉大学动力与机械学院,武汉430072

出　　处：《水力发电学报》2025年第2期63-75,共13页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金(52209114);湖北省自然科学基金(Grant No.2022CFD165)。

摘　　要：水电站多机共用尾水系统并网运行动态特性复杂,不利于机组高品质调控。为此,建立了水电站多机共用尾水调压室和尾水隧洞并网运行数学模型范式,研究分析了耦合系统的稳定性和动态特性。首先,采用Hopf分岔理论分析了耦合系统多机运行各机组的稳定域和分岔特性。进一步,仿真分析了典型控制参数对应耦合系统的动态特性。结果表明:耦合系统存在超临界Hopf分岔且不稳定机组的振荡特性会传递到稳定的机组,导致整个耦合系统中的机组发生低频振荡。各机组引水管水流惯性时间常数和负荷占比对耦合系统稳定域影响最大,引水管水流惯性时间常数越大,稳定域越小;负荷占比存在临界点,在临界点左侧负荷占比越大稳定域越大,在临界点右侧负荷占比越大稳定域越小。仅当各机组控制参数均在稳定域内,耦合系统才是稳定的。机组动态调节过程中,调压室水位由自身水力波产生超超低频振荡频谱,机组和电网频率包含由调压室产生的超超低频振荡和由调速系统、电网产生的低频振荡三种频谱成分。Dynamic characteristics of the grid connected operation of a multi-units-shared tailwater system in hydropower stations are complicated,which is unfavorable to high-quality regulation of the units.This paper develops a mathematical model paradigm for the multi-units-shared tailwater surge chamber and tailwater tunnel connected to the power grid,and examines the stability and dynamic characteristics of such a coupled system.First,the Hopf bifurcation theory is applied to an analysis of the stability domain and bifurcation characteristics of each unit operating in the coupled multi-unit system.Then,the dynamics of the system operating at typical control parameters are simulated and examined.The results indicate that this coupled system is prone to supercritical Hopf bifurcation,and the oscillation characteristics of its unstable units will be transmitted to the stable ones,leading to low-frequency oscillations occurring on all its units.The influence of the inertia time constant and load ratio on its stability region is the greatest.For each unit,the greater the inertia time constant of the flow in its pilot pipe,the smaller the stability region.A critical point of load ratios exists-on its left side,the larger a load ratio,the larger the stable region,while on its right,the larger a load ratio,the smaller the stable region.The coupled system is stable only when the control parameters of each unit stay in the stability region.During dynamic regulation,water level in the surge chamber generates ultra-ultra-low frequency oscillation spectrum by its own water surface wave.The frequencies of the unit and the power grid include ultra-ultra-low frequency oscillations generated by the surge chamber and low frequency ones generated by the speed regulating system and the power grid.

关 键 词：水电站 尾水调压室 电网 水轮机调速系统 稳定性 动态特性 

分 类 号：TK733[交通运输工程—轮机工程]