Dayingjiang hydropower station(Stage Ⅳ) original equipped with four Francis units of high head and high speed. Because the sediment concentrations of the hydropower station water flow is very high, in order to reduce the sediment erosion of turbine, necessary anti-abrasion measures from two aspects of hydraulic and structure have been taken during the original design stage, such as splitter blades runner, lower speed, sufficient cavitation margin, dismantling-from-below type of runner, on-contact main shaft seal and anti-abrasion material and so on. Later because the actual sediment concentrations through the turbine was too high and the sand with large size and high hardness. The main flow-through parts appeared varying degrees abrasion. A series of optimization and improvement measures were taken after discussion and analysis, such as building sediment pool, turbine design optimization, part flow-passing surface thermal spraying etc. It has achieved remarkable results, extended the overhaul period and increased the hydropower generation benefits. This paper summarizes and discusses this and hope it can give a reference for other counterparts and similar hydropower station on the river with large sediment concentrations.%大盈江水电站(四级)原安装4台高水头、高转速混流式机组,由于电站含沙量较大,为减轻水轮机磨损,初期设计时从水力和结构两方面采取了必要的防磨蚀措施,如:选用长短叶片转轮、较低转速、确保充足空化裕量;采用转轮下拆方式、非接触式主轴密封、抗磨蚀材料等.后因实际过机含沙量过大,且泥沙粒径大、硬度高,主要过流部件出现了不同程度磨损.经研讨分析,采取了一系列优化改善措施,如修建沉沙池、水轮机设计优化、局部过流表面热喷涂等.取得明显成效,延长了大修周期,增加了发电效益.本文就此迚行了总结和探讨.
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