Intra-annual Complementary Characteristics Of Wind-solar Resources Impact On Hydro-wind-photovaltaic Optimal Operation

As clean energy sources such as wind and solar power rapidly develop,their proportion in the power system is increasing.Their cleanliness,low carbon emissions,and sustainability are conducive to achieving China’s carbon peak and carbon neutrality goals.However,their randomness,fluctuation,and intermittency bring new challenges to the stable operation of the power grid.The complementarity of wind and solar resources can mitigate the impact of random output fluctuations on the power system.At the same time,hydropower has the advantages of flexible start-up and rapid regulation and is an ideal power source for compensating and regulating wind and solar power.The coordinated operation of water-wind-solar is an effective means to meet the challenges of new energy.In view of the fact that the complementarity of wind and solar resources will affect the decision-making scheme of water-wind-solar joint operation to a certain extent,studying the influence mechanism of wind-solar complementarity on the benefits of water-wind-solar coordinated operation has important value and significance for formulating dispatching schemes,optimizing energy structure,and improving resource utilization efficiency.This paper mainly involves two parts: the complementary characteristics of windsolar regions and the complementary scheduling benefits of water-wind-solar.The former takes national wind and solar resources as research objects,while the latter takes Long-yang Gorge and typical wind and solar power stations as research objects.It studies the fluctuation complementary characteristics of wind-solar resources,establishes a multi-objective scheduling optimization model for hydro-windphotovaltaic coordinated operation,analyzes the competition rules between multiple objectives in hydro-wind-photovaltaic joint scheduling under different wind-solar complementary conditions,and obtains the following main research conclusions:(1)For the quantitative evaluation of the complementarity of wind-solar resources,a complementary rate CR index for quantitatively calculating the fluctuation complementarity of time series is proposed.The annual complementarity characteristics of wind-solar resources within the country are calculated.Then,from both time and space perspectives,we analyze the evolution characteristics between years of wind-solar complementarity within China and regional trends.The results show that before 1990,China’s wind-solar complementarity showed a downward trend overall.Regions with strong wind-solar complementarity include Northeast China,North China,Inner Mongolia Autonomous Region,and some parts of Northwest China,The regions where wind-solar resources are less complementary are Southwest China.(2)Using Mann-Kendall trend test method and Hurst index to analyze the temporal change trend and future change trend of national wind-solar resources complementarity rate.The results show that most regions’ wind-solar complementarity rates show no significant change or significant downward trend.Some parts of Northeast China,Northwest China,Southwest China show an upward trend and may show a random walk trend in the future.(3)Taking maximizing joint power generation from water-wind-solar sources and minimizing output fluctuations as goals,we establish a multi-objective optimization scheduling model for water-wind-solar coordinated operation.Using NSGA-II algorithm to solve the model,we obtain optimized scheduling results under five typical scenarios.It shows that there is an obvious and complex competitive relationship between water-wind-solar coordinated power generation benefits and output fluctuations under different typical scenarios.Under different wind-solar complementary conditions,Pareto frontier distributions are different.There are differences in competitive relationships between multiple targets.When wind-solar complementarity is stronger,Pareto optimal solutions are more concentrated,the slope of Pareto front is larger and hydropower can better smooth out wind-solar fluctuations.However,when wind-solar complementarity is weaker,the Pareto optimal solution distribution is more dispersed,the slope of Pareto front is smaller,and the effect of hydropower to suppress the scenery fluctuation is weaker...