抽蓄机组流量不同步变化对尾水管低压的影响  

Influence of unsynchronous flow change of pumped storage unit on low-pressure of draft tube

作　　者：陈龙[1] 俞晓东[1] 林文雯 陈胜[1] 张健[1] CHEN Long;YU Xiaodong;LIN Wenwen;CHEN Sheng;ZHANG Jian(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing,Jiangsu 210098,China)

机构地区：[1]河海大学水利水电学院,江苏南京210098

出　　处：《排灌机械工程学报》2023年第9期899-905,共7页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51879087,51839008)。

摘　　要：尾水低压现象对抽水蓄能电站的设计影响显著,为阐明尾水低压现象出现机理,基于一洞两机抽水蓄能电站输水发电系统,采用刚性水体动量方程,研究了甩负荷过程机组尾水管低压现象.为揭示输水系统布置对尾水低压现象的影响机制,定义了流量不同步变化抑制系数,并基于特征线法建立了系统的过渡过程仿真模型,通过移动上下游岔管位置,对比抽蓄电站不同类型甩负荷工况的结果,研究了不同流量变化抑制系数对尾水管最小压力的影响.结果表明:尾水低压出现的本质是同一水力单元2台机组流量变化不同步引起的压力交替变化,进而加剧了机组自身的流量变化;随着流量不同步变化抑制系数的减小,甩负荷过程中流量交替变化现象和尾水管低压现象均得到改善.The low-pressure phenomenon of tail water of a pumped storage power station has a significant influence on the design of pumped storage power station.In order to clarify the mechanism of low-pressure phenomenon of tail water,based on the water transmission and power generation system of pumped storage power station with one hole and two machines,the low-pressure phenomenon of draft tube in unit during load rejection process was studied by using the rigid water hammer theory.To reveal the mechanism of the influence of the water conveyance system layout of tail water low-pressure phenomenon mechanism,the suppression coefficient of unsynchronized flow change was defined,and based on the characteristic line method,the system transition process simulation model was established.By moving the upstream and downstream bifurcations pipe position,the results of different kinds of working condition of load shedding pumped storage power station were compared,and the influence of the different changing flow suppression coefficient on minimum pressure of the draft tube was studied.The results show that the essence of low tail water pressure is that the flow rate of two units in the same hydraulic unit is not synchronized,which further leads to the alternating change of pressure,and then aggravates the flow rate change process of the unit itself.With the decrease of the inhibition coefficient of flow asynchronism,the phenomena of flow alternating change and the low pressure of draft tube in the process of load rejection are improved.

关 键 词：抽水蓄能水电站 甩负荷 输水系统布置 过渡过程 尾水管进口最小压力 

分 类 号：S277.9[农业科学—农业水土工程]