三峡水电站水轮机稳定性分析

Operation stability analysis of TGP's turbines

混流式水轮机偏离最优工况运行有可能诱发机组的不稳定运行。三峡水电站在电力系统中具有举足轻重的作用，故水轮机的稳定性成为评价三峡水轮机性能的重要指标之一。三峡水利枢纽由于防洪需要，水头变幅大，且高、低水头历时时间长；机组在电网中承担峰荷，高水头时负荷变化大，导致水轮机长时间偏离最优工况运行，有可能存在稳定性问题。在分析大古力、依泰普等与三峡水轮机接近的大型混流式水轮机稳定性问题的基础上，对三峡水轮机高、低水头偏离最优工况运行的稳定性进行了分析。并在此基础上，提出了对三峡水轮机稳定性的要求。

Francis turbine’s operation out of the optimal mode may induce unstable operation of the generating unit. Three Gorges power station will occupy a decisive position in the power grid. Therefore,the operation stability is one of the most important indexes for appraising the behavior of the hydraulic turbines for the Three Gorges power station. Due to the requirements for flood control the hydraulic turbines of the station will operate with wide head variation,and the duration of operation both at high head and at low head will be relatively long. The generating units will undertake the peak load in the power grid and the load will change greatly at high head. This will result in the turbine’s operation deviating from the optimal mode for long period,so it is possible to bring about some problems on operation stability. On the basis of analysing the stability problems arising in operation of the turbines of the Grand Coulee and Itaipu power stations,etc.,of which the turbines have the capacity close to that of the Three Gorges power station’s turbines,the stability of the Three Gorges power station’s turbine operating at high head and low head, away from the optimal mode, is analysed in this paper;and therefore some requirements for the stable operation of the turbines of the power station are put forward.