基于调度图的金沙江下游梯级水电站改进蓄水策略研究

Dispatching diagram-based study on improved impoundment strategy of cascade hydropower stations of lower Jinshajiang River

为缓解金沙江下游梯级水电站汛末蓄水矛盾,改善蓄水过程中按调度图运行存在下泄流量、出力过程波动较大等问题,以溪洛渡、向家坝梯级水电站为研究对象,通过设置不同提前蓄水时机组合,提出基于水电站调度图的改进蓄水策略,并从年平均蓄满率、汛末蓄水位、总弃水量、总发电量等指标综合比较分析,确定了当起蓄时机为溪洛渡9月1日、向家坝9月1日,并采用改进蓄水策略蓄水时,为梯级最佳蓄水方案。同时,采用丰、枯典型年对蓄水过程进行验证。研究结果表明:提前起蓄时机有助于水电站提早蓄滞一部分汛末水量,缓解梯级水电站间的蓄水矛盾;改进蓄水策略充分利用调度线的过渡作用,有助于减少水电站出力在不同调度区之间大幅度来回跳动,实现了下泄流量、出力过程稳定。该研究成果可为金沙江下游梯级水电站汛末蓄水调度提供科学的参考依据。

In order to alleviate the contradiction from the impoundment of the cascade hydropower stations of lower Jinshajiang River at the end of flood season and to solve the problems of large discharge,large fluctuation in the generation output process,etc. from the dispatching diagram-based operation during the water impounding process,an improved reservoir dispatching diagram-based impoundment strategy is proposed herein through setting up different combinations of advanced impounding opportunities by taking cascade hydropower stations of Xiluodu Hydropower Station and Xiangjiaba Hydropower Station as the study objects,and then the indexes,i. e. the annual mean impoundment rate,the storage level at the end of flood season,total abandoned water,total power generation,etc. are comprehensively compared and analyzed,from which it is determined that the optimum impoundment scheme for the cascade is to take September 1 st as the starting opportunity of the impoundment for the reservoirs of both the hydropower stations when adopting the improved impoundment strategy for the impoundment,meanwhile,the impounding process is verified with those of wet and dry years. The study result shows that putting the starting opportunity of impoundment forward is helpful for the hydropower stations to store a part of water at the end of flood season in advance,and then alleviates the contradiction from the impoundment between the cascade hydropower stations. Improving the impoundment strategy and fully utilizing the transition effect of the dispatching diagram are helpful for decreasing the repeated fluctuations within a large range of the power generation output in-between different dispatching intervals,thus the stabilities of both the discharge and the power generation output process are realized. The study result can provide a theoretical reference basis of dispatching the water impoundment at the end of flood season for the cascade hydropower stations of lower Jinshajiang River.