周宁抽水蓄能电站下水库泄洪建筑物布置方案研究

Study on layout for flood-discharge structure of lower reservoir for Zhouning Pumped-Storage Hydropower Station

针对周宁抽水蓄能电站调节库容小、洪水调节能力差,而且洪水的洪峰流量和洪量大等特点,用调整表孔、底孔结构尺寸的方式进行泄洪规模和表底孔泄洪能力分配的比选,探讨其泄洪建筑物的布置原则。不同方案的对比研究表明:最大下泄流量应以校核洪水下高水位时局部时段敞泄为原则进行设计,以减小闸门控制误差所造成的洪水雍高风险。对于调节能力差、洪水流量大的抽水蓄能电站工程,应布置表孔、底孔进行联合泄洪;底孔的布置应保证低水位时各频率洪水均得到快速下泄,避免在水位上升过程中出现滞洪现象;在总超泄能力满足泄洪要求的前提下,应选择表孔规模较大的方案,实现表孔和底孔泄流能力的优化分配。研究成果对调节能力差、洪水流量大的电站工程建设具有借鉴意义。

Aiming at the characteristics of small regulation storage capacity,poor flood regulation ability,large peak flood flow and flood volume,etc.,the flood discharge scale and the distribution of the flood discharge capactities of both the boltorn and surface outlets are compared and selected by the mode of adjusting the structural size of the surface outlet,and then the principle of the layout of the flood discharge structure is discussed as well. The comparative study made on various schemes shows that the maximum discharge flow must be designed by taking the open discharge of partial time interval during high water level under the check flood level as the principle,so as to reduce the risk of back-up flood caused by the error from the control of gate. For those pumped-storage hydropower stations with poor regulation ability and large flood flow rate,the joint-flood discharge of surface outlet and bottom outlet must be adopted; for which the layout of the bottom outlet must ensure the rapid discharges of the floods of all the frequencies under lower water level,so as to avoid the phenomena of flood detention occurred during the rising of water level,while the scheme of larger scale of surface outlet must be selected under the premise of that the over-discharge ability can meet the requirement of the flood discharge,so as to realize the optimal distribution of the discharge capacities of both the surface and the bottom outlets. The study result has a certain reference significance for those hydropower projects with poor regulation ability and large flood flow rate.