Impact of Dispatching of Reservoirs in the Upper Yangtze Riveron on the Operation of the Three Gorges Cascade Hydropower Station

The Upper Yangtze Riveron has many tributaries and abundant water resources. Now they have formed the largest mixed-flow cascade reservoir group in China. The Three Gorges cascade hydropower station is the last stage of the cascade hydropower stations in the Upper Yangtze Riveron,whose operation is deeply affected by upstream reservoirs dispatching.Based on the 1997-2016 operation data of 26 key reservoirs in the upper reaches of the Three Gorges Reservoir, the variation law of the cascade hydropower station’inflow and power generation under the influence of upstream reservoir group dispatching is clarified.The results show the upstream reservoir group dispatching is storaging water during flood season and supplying water in the dry season, which optimizes the distribution of Three Gorges Reservoir inflow during the year, then indirectly increases the power generation of the Three Gorges cascade hydropower station. Under the dispatching level in 2016, the annual storage capacity of the upstream reservoir group will increase the annual electricity of the Three Gorges cascade hydropower station by 4.01 billion kw·h, and the increase is mainly concentrated in the dry season. The results can provide decision-making reference for the medium and long-term planning of the Three Gorges cascade hydropower station, which is of great benefit to improving the dispatching level of the cascade hydropower station.