Research On Reservoir Optimization Operation Of Xijiang River Basin Based On The Bi-objective Lion Pride Algorithm

The reservoir multi-objective optimization operation plays a vital role in water resources development and management,and the bi-objective optimization is the basis of the multi-objective optimization.Therefore,it is of great significance and practical value to study the reservoir bi-objective optimization operation.This paper focused on the bi-objective optimization via proposing a novel optimization algorithm called the bi-objective lion pride algorithm(LPA),and verified the effectiveness of LPA in solving the bi-objective optimization problems.The application of LPA in the reservoir medium-long-term bi-objective optimization operation has achieved satisfactory results.The main research results achieved in this paper are as follows:(1)Aiming at the shortcoming of the individual evaluation indices of NSGA-Ⅱ and referring to the social structure of the wild lion prides,a novel bi-objective optimization algorithm based on NSGA-Ⅱ framework,called the LPA,was proposed.In ZDT test problems,LPA outperforms NSGA-Ⅱ in terms of convergence and diversity,and it runs about 2 to 4 times faster than NSGA-Ⅱ.At the same time,in the complex bi-objective problems with sharp-peak and long-tail POFs(Pareto-optimal fronts),compared with NSGA-Ⅱ,NSGA-Ⅲ and MOEA/D,the performance of LPA is still stable and its nondominated fronts converge well around the entire POFs.(2)Due to the limitation of the slope index in judging the nondominated relationship,compared with NSGA-Ⅱ,the proportion of nondominated solutions in LPA is slightly reduced But the reduction range is only between 0.05%and 2.24%in both the ZDT test problems and the Xijiang reservoir optimization operation problems,indicating that this limitation has little adverse impact on the performance of LPA.(3)Six reservoir operation scenarios were set up,and the reservoir medium-long-term bi-objective optimization operation models of the Xijiang River Basin were established.The models were solved by LPA and NSGA-Ⅱ respectively,and the optimal operation results under the six scenarios were obtained.Compared with simulation operation,optimization operation simultaneously improves the annual power generation and the minimum monthly output of the reservoir system,and provides a rich set of optimal solutions for decision makers.In addition,compared with NSGA-Ⅱ,LPA can shorten the running time of the optimization operation models by 10%to 28%,and its optimal solution sets are also better.(4)Taking the power generation operation of the cascade reservoirs as an example,the similarities and differences between the single-objective operation scheme and the bi-objective operation scheme were analyzed.The results show that for the single-objective operation scheme that considers only the maximization of the annual power generation and the bi-objective operation scheme that considers both the maximization of the annual power generation and the maximization of the minimum monthly output,the annual power generation of these two scheme is very close,but the bi-objective operation scheme also increases the minimum monthly output of the cascade system which making the output process more stable and is conducive to maintaining the stability of the power system.