【作者】 王俊娜；

【导师】 练继建；

【作者基本信息】 天津大学 ， 水利水电工程， 2008， 硕士

【摘要】 在温度、光照适宜的3～5月份,三峡水库支流的局部水域易暴发“水华”现象。其主要原因是蓄水后支流由天然状态的流速1～2m/s变成几乎静止,水体紊动和水流流速的降低,造成营养盐的富集和藻类的快速生长。而三峡电站非汛期采用调峰运行,电站调峰有利于干支流水体交换,增大水体紊动和水流流速,从而为改善支流的水质提供了新契机。本文主要研究三峡电站调峰对水库水流水质的影响规律,并通过建立非汛期生态调度模型寻求对库区水质改善和电站发电综合最优的调峰运行方式。主要有以下几个方面:(1)根据三峡电站非汛期的调峰容量和最小生态需水量,通过EFDC模型模拟不同水位、不同流量和不同调峰幅度对水流水质的影响,分析能够使支流流速达到临界流速时不同水位对应的流量。(2)建立准确模拟电站调峰运行时水流水质状况的简单生态动力学模型,模拟整个非汛期不同下泄流量过程对应的营养盐浓度过程,计算出不同调度方式对应的营养盐平均浓度。(3)建立改善非汛期三峡水库水质的生态调度模型,即在常规发电调度模型基础上,增加通过水流水质模型计算出的不同调度方式对应的营养盐TP浓度最小化的目标函数,以及满足生态环境基本需求的最小生态需水量和抑制藻类生长的临界流速的约束条件。(4)采用基于遗传算法的多目标模糊规划法求解生态调度模型。根据典型年来流量和库区TP负荷,得出对水质有较大改善作用又能满足发电量要求的调峰调度运行方式,给今后三峡电站非汛期的调峰运行提出建议。更多还原

【Abstract】 During March-May, water bloom phenomenon has taken place in some parts of the Three Gorges Reservoir’s tributaries. The high water level results in the decreases of the flow velocity and turbulence, which leads to the enrichment of nutrient and fast growth of algae. While in non-flood season, Three Gorges Power Station will be in peak-load operation, which will benefit the water exchange between main stream and tributaries and increase the water turbulence and velocity. Therefore, the peak load operation will provide a new way to improve the water quality of tributaries.In the paper, the impact of peak load operation on hydraulics and water quality is researched. The best peak load operation mode for both water quality and power generation is found by establishing the ecological optimal dispatching model. The main research work focuses on the following aspects.First of all, according to the peak-load regulation capacity and the minimum ecological water requirement, the influences of hydraulics and water quality under different water level, different flow and different peak-load regulate amplitude is simulated in the second part of the paper. Then, by analyzing the results, the corresponding flow discharge of different water level under which the velocity of the tributary can reach the critical velocity of suppressing algal growth is obtained.Next, the simple ecological dynamics model reacting to the hydraulics and water quality status in peak-load regulation is set up in the third part of the paper. The model can simulate the nutrient density process of the whole non-flood season, then, the average nutrient density of different dispatching mode is gained.In addition, in the last of the third part, an ecological dispatching model of the Three Gorges Power Station is built. The basic thought is based on the conventional power generation optimal dispatching model, with another one objective function and two constraint conditions added. The objective function is the minimum of the TP nutrient density calculated by the ecological dynamics model. One of the constraint conditions is the minimum of the ecological water requirement; the other is the critical velocity above which the algal growth can be suppressed.Lastly, the muti-objective fuzzy program is used to resolve the ecological optimal dispatching model based on genetic algorithm. According to the coming water flow and the TP pollutant load, the paper computes the best peak-load dispatching mode in which the water quality of the reservoir can be improved and the power generation can be satisfied. Therefore, some useful suggestions will be provided for the Three Gorges Power Station when it works in peak-load mode.更多还原