Detailed analysis was conducted for the optimal operation mode of cold end system of power plant based on the principles of "energy value analysis", which overcome the shortcoming of the traditional analysis method.

This paper presents an analysis method to synthesize the discharge curve at optimum equi-efficiency from hill diagram (pump turbine characteristic) and to determine the optimum operation scheme line and optimum load distribution among turbine units in pumped-storage plant.

By analyzing the water-level change of the lake,the paper illustrates the cause of water-level change, discusses a series of eco-environment problems caused by water-level change, and points out in order to prevent the decrease of eco-efficiency, studies on the optimal operational water-level of the Ebinur lake must be conducted, combining with the actual situation of the river basin, h.