Targeting the hub project of multi-branched rivers in Ganjiang River estuary, this study conducts researches on technical schemes including dam site selection, ship lock and sluice layout. An evaluation index system containing 14 indicators is established from three dimensions namely economic benefit, ecological protection benefit and social benefit. Representative stakeholders including government construction departments, ecological and environmental protection departments, local communities and construction enterprises are selected. The analytic hierarchy process (AHP) is adopted to determine subjective weights, and the Shapley value method is used to introduce game theory mechanism for combined weighting. Meanwhile, the entropy weight method is applied to calculate objective weights, and the effects of various subjective and objective weighting methods are compared. Finally, the TOPSIS method is used to optimize all alternative schemes. The research results show that stakeholders have obvious differences in indicator preference. Governments and enterprises pay more attention to economic benefits, environmental protection departments focus on ecological protection benefits, while communities prioritize social benefits. Game based weighting can effectively balance the demands of all parties. Combined with objective weights, the overall weight distribution becomes more balanced, which improves the fairness and objectivity of evaluation results. The comparison results indicate that the discrepancy among schemes mainly depends on the coverage scope of layout units and the convergence degree of external constraints. Layout schemes such as sluice on the south branch, ship lock on the middle branch and dam site on the north branch have close comprehensive scores due to fewer involved indicators and similar indicator values, while distinct differences exist among other schemes.

Conventional intelligent optimization algorithms are inefficient or even impossible in finding feasible solutions to the cascade reservoir optimal operation calculations with small time step and a large number of calculation periods. On this basis, an improved NSGA-Ⅱ algorithm is proposed to solve the problem. Based on the framework of NSGA-Ⅱ algorithm, the improved algorithm introduces reference goal value, potential goal value, offset degree and mutation guiding operator to optimize the population evolution process and to enhance the quality of populations in the evolution process, making the solution set as close as possible to the true Pareto-optimal front. The verification results from a multi-objective optimal operation case study of cascade reservoirs in the Jinxi River Basin of Fujian Province show that the improved NSGA-Ⅱ algorithm has higher computational efficiency and better optimization results compared to other algorithms, demonstrating good practicality.

Aiming at the problem of the significant decline in source-load synchronization of a hydro-photovoltaic complementary system under the penetration of a high percentage of photovoltaic power generation, a nested scheduling model that couples long-term water storage regulation in the outer layer with short-term power complementary in the inner layer is constructed. The model identifies the characteristics of photovoltaic output and load curve in the outer layer, while in the inner layer, based on the source-load matching mechanism, it divides the transmission channel into multiple target spaces according to the characteristics of water, light and load. The model employs the coupling linkage mechanism of intra-layer target classification and inter-layer global search to solve the power allocation of the transmission channel and obtain the power distribution in each target space. The results of the case study of the hydro-photovoltaic complementary system in the Xizang section of the Lancang River show that the constructed model can effectively guide the operating conditions of the system to approach the target preference region, and the formulated scheduling scheme can meet the requirements of short-term power curtailment, fluctuation risk control and power peak regulation, verifying the rationality of the model.

In order to optimize the capacity configuration scheme for a hydro-photovoltaic complementary clean energy base, a comprehensive evaluation index system was constructed by selecting 14 indicators from the 4 aspects of safety, environmental protection, economy, and technology. An improved cloud model method was used to evaluate the capacity configuration scheme. The improved cloud model based on analytic hierarchy process was used to solve the subjective weights, the entropy weight method was used to solve the objective weights, the combined weighting was used to obtain the indicator weights, and then a conditional cloud generator was used to calculate the membership degree of each indicator. Finally, based on the level eigenvalue method, the capacity scheme rating was calculated to determine the optimal scheme. The method was applied to the optimization of the capacity configuration scheme for a hydro-photovoltaic complementary clean energy base in Southwestern China. The optimization results are consistent with the set pair analysis method and the actual selection scheme, proving the effectiveness and applicability of the method.