Abstract:In view of the problem that there are a large number of infeasible solutions affecting the optimization efficiency when NSGA-Ⅱ is applied to the optimal scheduling of cascade hydropower stations, considering the mutual restriction relationship between adjacent stages, an improved NSGA-Ⅱ algorithm based on the bidirectional constraint technology of individual facing period is proposed. Taking the Longjiang Hydropower Station(upstream)and the Ruilijiang Ⅰ Hydropower Station(downstream)in the Longjiang-Ruilijiang Basin as examples, a multi-objective joint optimal scheduling model is established to optimize the optimal scheduling scheme in hydrological typical years, and compared with the independent scheduling of hydropower stations. The results show that the improved algorithm solves the problem that the infeasible solution participates in evolution and even converges to the infeasible Pareto front. As the incoming water dries up, the range of Pareto front tends to narrow in typical years, the storage time of Longjiang hydropower station in flood season is gradually advanced, and the decline time of water level in dry season lags behind. Compared with independent scheduling, the runoff compensation effect of joint scheduling slightly reduces the power generation of the Longjiang Hydropower Station, while the total power generation of the system increases by 3. 47% ~ 10. 02%, which also significantly reduces the waste water of Ruilijiang I Hydropower Station in dry season.