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大型水电站一般取第一台机组投产后的5年或10年作为设计水平年,三峡工程规模大、工期长,以取第一台机组发电后10年作为设计水平年为宜,照目前情况应取2015年作为设计水平年,根据电力规划以及葛洲坝水位的提高和调节库容的扩大可以满足下游通航水深要求,三峡水电站装机容量可扩大到2000万kW左右,单机宜选68～80万kW的机组较为合理,三峡水库运行受防洪、泥沙等因素制约,采用蓄清排浑方式,汛期与汛后水头变化大,初期低水头发电长达8年之久,加上长江水中泥沙对水轮机磨蚀,使最优效率点水头的选择比较困难,从运行可靠出发,将最高效率点水头选择靠近汛期水头,以减少气蚀、泥沙联合磨蚀,并限制其在高水头下的运行小时数较为现实可行,初期发电机组台数少、水头低。如何加大水轮机单位流量,尽可能多地利用长江充沛的水量;提高水轮机低水头发电的效率,早发电、多发电是进一步研完的重要课题之一。
Large hydropower stations generally take the first unit put into operation 5 years or 10 years as the design level of the year, the Three Gorges Project large scale, long duration, to take the first unit 10 years after the power generation as the design level is appropriate, according to the current situation should Taking 2015 as the design level year, according to the power planning and the improvement of Gezhouba water level and the expansion of regulating capacity, the water depth of downstream navigation can be satisfied. The installation capacity of Three Gorges Hydropower Station can be expanded to about 20 million kW, It is reasonable that the operation of the Three Gorges Reservoir is restricted by factors such as flood control and sedimentation, and the method of clearing and discharging muddy is adopted. The flood head and flood head changes greatly after flood season, and the initial low-head power generation lasts for 8 years. Coupled with the erosion of water turbines in the Yangtze River water, , Make the choice of the optimal efficiency of the head more difficult, starting from the reliable operation, the highest efficiency point head close to the flood season head, in order to reduce cavitation erosion and sediment joint erosion, and to limit its operating hours in the high head more realistic Feasible, the initial number of generating units less head low. How to increase the unit flow rate of the turbine and make full use of the plentiful amount of water in the Yangtze River? To improve the efficiency of the turbine with low water head power generation, it is one of the important topics for further research to complete the project.