极端枯水条件下梯级水库蓄水调度策略--以金沙江下游-三峡梯级为例

Reservoir impounding strategies of cascade reservoirs under extreme low-flow conditions.Case study of lower Jinsha River and Three Gorges cascade reservoirs

以发电效益最大为目标,探究适应极端枯水条件的金沙江下游和三峡梯级水库蓄水策略。结合蓄水效益最大规则和三峡供水调度需求,提出了极端枯水条件下梯级水库蓄水调度方式,以蓄水位目标为控制边界拟定不同水量分配原则的蓄水方案,选择典型极端枯水进行模拟调度和效益分析。结果表明:梯级水库蓄满的临界天然来水条件为8月—9月上旬来水不少于97%频率的典型来水(1994年),9月中旬—11月来水不少于90%频率的典型来水(1992年);极端枯水条件下,梯级水库通过开展联合补水调度,能够满足三峡向下游供水的调度需求;梯级水库无法全部蓄满情况下,优先蓄满金沙江下游梯级水库可使发电效益更大,推荐优先蓄满白鹤滩水库,其次溪洛渡水库。

To maximize power generation benefit,this study explores reservoir impounding strategies adapted to extreme low-flow conditions in the case of the lower Jinsha River and the Three Gorges cascade reservoirs,and presents a new reservoir impounding scheme by combining the impounding rule of benefit maximization and the water supply requirement of the Three Gorges Reservoir.We also examine alternative reservoir impounding schemes aimed at different water allocation principles that meet the targets of reservoir stages or the control boundaries.Typical extreme low-flow scenarios are simulated numerically for operation and benefit analysis.From the results,we demonstrate a critical condition of natural inflow for full filling of the cascade reservoirs-the natural inflow is above the level at the frequency of 97%from August through early September,and above the level at the frequency of 90%from mid-September through November.Under extreme low-flow conditions,the cascade reservoirs will be able to perfectly fulfill the water supply requirement of the Three Gorges Reservoir if they adopt a certain joint water supply dispatching.In the case of a full filling impossible,their power generation benefit can be maximized by impounding preferentially those in the lower Jinsha River,such as the Baihetan Reservoir first and then the Xiluodu Reservoir as recommended by this study.