水电站中长期优化调度主要是在满足电力系统出力要求以及下游综合用水要求等的前提下，合理地安排水库各个月份的发电流量，使得调度期内的总发电量最大。即在给定预报入库流量过程线、下游综合用水流量过程线、调度期起始水位和终止水位等条件下，通过总水量的合理运用使调度期内水电站的总发电量最大。-Long-term optimal operation of hydropower stations mainly in the power system to meet the output requirements, and integrated water requirements downstream of the premise, reasonable arrangements for generating reservoir flow each month, making the scheduling period, the largest amount of total power generation. That is forecast in a given inflow hydrograph, downstream water discharge hydrograph synthesis, scheduling and termination of the initial water level and water level conditions, the total amount of water through the rational use of the scheduling period, the total generating capacity of the largest hydropower station.