Study On Short-term Optimal Scheduling And The Influence Of Unsteady Flow On Navigation Of Three Gorges Cascade

The temporal and spatial distribution of hydro energy resource differs greatly in China. There is remarkable compensation benefit between hydropower and thermal power as well as reservoir group. With the generation of Three Gorges and the formation of the whole power networks in China, it is necessary to deploy an optimal compensative operative among reservoir groups, multi-area reservoir groups, which based on the asynchronous rule of incoming flow from different reservoirs. The goal of cascade optimal dispatching is to gain the maximal economic benefit from the whole cascade hydro energy under the constraints of the operation of hydroplant. On the other hand, since most of the national and international researches on the economic operation of hydroplant considered the influence of the downriver unsteady flow on the navigation caused by station peak shaving only in simple way, the gain operation mode is not likely to be global optimal. In the problem of the operation of hydro plant and cascade hydroplant in main river course, it is very important to study the influence of the unsteady flow on generation and navigation, which results from peak shaving, and then to make a reasonable generation and navigation daily plan.Following the trace presented above, this thesis, combining the two practical projects "Three Gorges Cascade Hydropower Unit Scheduling" and "Three Gorges Cascade Decision Support System", studied the model and algorithm of cascade short-term optimal operation, discussed navigation problem and gained some referenced result. At first the thesis summarized cascaded reservoir optimal operation. Reviewed the current optimal theories and methods, we pointed out the merits and shortcomings of each method. And we described briefly about unsteady flow problem.There are two main parts in this thesis. Firstly the calculating method and detailed realizing process about cascade optimal operation was introduced. The model when the hourly releases of Gezhouba are fixed was discussed completely. This model was divided into three sub models, the target functions are: 1) gaining daily maximum power generation, 2) gaining daily maximum generating revenue, 3) gaining daily maximum peak shaving revenue. Among them, the sub models 1 and 2 applied status variable space dynamic programming. All the three sub models were simulated and computed and the results were compared to express the rationality and practical meaning of the sub models directly.Secondly the navigation problem was considered. We discussed thoroughly about the navigation constraints and unsteady flow problem. The thesis establishes a one-dimension unsteady flow model based on the topography feature of the river course between Three Gorges and Zhicheng. Under the given navigation restrictions and the designed peak shaving flow of Three Gorges, studying the influence of the downriver unsteady flow on the navigation, and thereby through regulating the water level of Gezhouba hydroplant and reregulating the peak shaving flow of Three Gorges, gaining a new curve of Three Gorges hydroplant for satisfying the navigation demand.Finally, summarized the works we have done and prospected further study for future research.