巴基斯坦科哈拉水电站工程以库代池研究

Study on Replacing Desilting Basin with Reservoir of Kohala Hydropower Project

巴基斯坦科哈拉水电站额定水头300 m,为高水头冲击式水轮机组,机组对过机含沙量的要求非常高。对入库水沙特点、冲沙流量、冲沙时间、水位下降幅度、引水含沙量等进行深入分析,并结合水库泥沙数学模型计算分析成果,科哈拉水库实行按流量分级调度的运用方式,在汛期"壅水沉沙、敞泄排沙",使水库起到有效替代沉沙池的作用,亦使水库能在正常蓄水位与最低发电水位之间保持一定的有效库容进行日调节发电,并能大幅减少过机泥沙含量.以减轻对水轮机过流部件的磨蚀。

The rated head of Kohala Hydropower Station in Pakistan is 300 m,the turbine is of high head impulse turbine unit,it has high requirements on the sediment concentration through turbines.After profound analysis on the inflow water and sediment characteristics,sand flushing discharge,sand flushing time,water level drop,water sediment concentration,and in combination with the calculation results of mathematical model for sediment in the reservoir,the reservoir adopts the dispatching mode of flow classification,in flood season,it deposits sediment in backwater and open discharge,the reservoir plays the role of desilting basin;it can also keep a certain effective storage between normal water level and the minimum power generation level for daily regulation,and significantly reduce the sediment concentration in the machine to alleviate abrasion on the water-passing components of turbine.