基于水沙模拟的抽水蓄能电站泥沙防治措施及优化布置研究

发布时间：2018-08-14 11:27

【摘要】：基于抽水蓄能电站在电网中担当的调峰填谷、调频、调相、紧急事故备用等独特作用和显著的经济效益、生态环境效益,我国抽水蓄能电站建设从上世纪90年代进入快速发展时期,并成为我国电力工业中不可缺少的重要组成部分。与常规水电站相比,抽水蓄能电站的库容相对较小,上、下库循环抽放水运行,机组频繁进行启动与停机过程。因此,河流上修建抽水蓄能电站时,在项目规划设计阶段必须对泥沙问题进行充分研究。本文针对某抽水蓄能电站下库区频率洪水过程的泥沙问题进行模拟和优化研究。首先,本文针对某抽水蓄能电站专用临时水文站实测水沙资料较少的实际问题,利用相邻李青店水文站和白土岗水文站位作为水沙设计的参考站,基于三个流域范围同属于一个侵蚀模数区、多年平均降雨量在同一等值区、产汇流条件相近等特点,采用水文比拟法对下水库长系列年和频率洪水来水来沙进行分析设计。其次,利用河工模型对某抽水蓄能电站下库区进行了特征洪水过程及电站运行的联合模拟试验。试验表明在输沙槽与拦沙潜堰共同作用下,比较好的调控了主流输沙,但是底部浑水会逆行至电站进出水口附近,导致过机含沙量较高。20年频率洪水期抽水蓄能工况运行时,实测含沙量在0.25~1.1kg/m3之间,高于抽水蓄能电站安全运行过机含沙量值。同时,发现由于泄洪排沙洞进流不畅、泄流能力不足等问题,导致其拉沙、排沙效果不是很好。针对物理模型试验中发现的问题,本文提出增设非封闭式拦沙潜丁坝和加高拦沙潜坝的优化方案一与改变泄洪排沙洞进口位置和扩大进口尺寸,变动原设计方案围堰位置的优化方案二,并基于MIKE21 FM系列软件,对其原设计方案和优化方案进行不同运行工况的二维水沙数值模拟。模拟结果显示,与原设计方案相比,优化方案一对于减小下库区泥沙淤积总量的效果并不突出,但是明显降低了电站进/出水口前的泥沙淤积厚度。优化方案二在电站不运行工况下,泥沙淤积量减少了3.563万m3,排沙比增加22.52%;在电站发电运行工况下,泥沙淤积量减少了2.006万m3,排沙比增加12.77%,极大的降低了库区泥沙淤积总量,同时对于电站进/出水口前泥沙淤积厚度的减小幅度与优化方案一基本保持一致。
[Abstract]:Based on the unique function and remarkable economic benefit, ecological and environmental benefit of pumped storage power station in power network, such as peak and valley regulation, frequency modulation, phase adjustment, emergency standby, etc. The construction of pumped storage power stations in China has entered a period of rapid development from the 1990s and has become an indispensable part of the electric power industry in China. Compared with conventional hydropower stations, the storage capacity of pumped storage power station is relatively small. Therefore, during the construction of pumped storage power stations on rivers, the sediment problem must be fully studied in the stage of project planning and design. In this paper, the sediment problem of frequency flood in reservoir area under a pumped storage power station is simulated and optimized. First of all, aiming at the practical problem that the measured water and sediment data of a special temporary hydrological station of a pumped storage power station is less, the adjacent Li Qing hydrologic station and the Baitugang hydrologic station are used as reference stations for the design of water and sediment. Based on the characteristics that the three basins belong to the same erosion modulus area, the annual average rainfall is in the same equivalent area, and the conditions of runoff production and confluence are similar, the hydrological analogy method is used to analyze and design the flood sediment for the long series of years and the frequency of the lower reservoir. Secondly, the combined simulation test of characteristic flood process and operation of a pumped storage power station in the reservoir area is carried out by using the river engineering model. The test results show that under the combined action of the channel and the submerged Weir, the mainstream sediment transport is well regulated, but the bottom muddy water will retrograde near the inlet and outlet of the power station, resulting in a higher sediment content. The measured sediment content between 0.25~1.1kg/m3 and Pumped-storage Power Station is higher than that of Pumped-Storage Power Station. At the same time, it is found that the effect of sand discharge is not very good because of the problems such as poor inflow and insufficient discharge capacity of flood discharge and sand discharge tunnel. In view of the problems found in the physical model test, this paper puts forward the optimization scheme of adding non-enclosed submerged dipping dike and heightening silt-arresting submersible dam. One is to change the inlet position and enlarge the size of the inlet of the flood discharge and sand discharge tunnel. Based on the MIKE21 FM series software, the original design scheme and optimization scheme are simulated under different operating conditions. The simulation results show that, compared with the original design, the effect of the optimization scheme 1 on reducing the total sediment deposition in the lower reservoir area is not obvious, but the sediment deposition thickness before the inlet / outlet of the power station is obviously reduced. Under the condition that the power station is not in operation, the sediment deposition amount is reduced by 35630 m3 and the sediment discharge ratio is increased by 22.522.Under the operation condition of the power generation plant, the sediment deposition amount is reduced by 20060 m3, and the sediment discharge ratio is increased by 12.77%, which greatly reduces the total sediment deposition in the reservoir area. At the same time, the decrease of sediment deposition thickness before the inlet / outlet of the power station is basically consistent with the optimized scheme.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV743

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