Research On Multi-objective Scheduling Methods Of Hydro-Wind-PV Complementary Power Generation System In The Lower Reaches Of Yalong River

It is of great significance to improve the utilization efficiency of wind power and photovoltaic power and ensure the safe and stable operation of power grid by studying the multi-scale scheduling methods of hydro-wind-photovoltaic(PV)hybrid power generation system in large river basin.The complementary power generation system formed by the downstream of Yalong River casade power stations and the nearby wind power fields and photovoltaic power stations is taken as the case study in this paper.Combined with the characteristics of stable load demand in the power transmission mode,the optimal scheduling model of cascade hydropower stations is established,and the optimization algorithm suitable for model solution is proposed.The medium and longterm on the monthly and ten-day scales and 96-point short-term optimal operation modes of cascade hydropower stations under the multi-energy complementary scheduling mode are discussed.The main work as well as the research results include the following aspects:(1)In order to reveal the impact of multi-energy complementary operation on the operation mode of cascade hydropower system,the multi-objective optimal operation model considering the maximum and minimum power generation at medium and longterm scale has been constructed for the two modes of ‘ multi-energy complementary operation ’ and ‘ cascade hydropower system in isolated operation ’.Then,the Pareto front of the solution set of the long series multi-objective optimization operation are obtained,and the water level process and output process of three typical hydrological years are compared and analyzed.The results of the case show that the peak regulation capacity of the cascade hydropower system is mainly used to drive the cascade hydropower station to store water in the early stage and supplement the output of the wind and photovoltaic power output process,while the degree of complementarity depends on the utilization of the hydropower peak regulation capacity.(2)In order to explore the joint operation mode of cascade hydropower stations under hydro-wind-PV complementary operation,a medium and long-term implicit stochastic joint scheduling function model of the complementary system based on SVM is established.The POA is used to optimize the main parameters of the model(C-penalty coefficient,γ-kernel function parameter,ε-insensitive loss coefficient),the water level,inflow,wind and PV output obtained in the research content(1)are taken as the model input,and the Gaussian radial basis kernel function is used to fit the operation function of the cascade reservoirs in the lower reaches of the Yalong River,and two strategies are proposed for simulation calculation of the case.It is found that the proposed method can effectively solve the problem of joint operation of cascade hydropower stations with wind-PV integration in the medium and long-term,and the output process is more stable with the developed rolling simulation strategies,which has certain practical value.(3)A multi-objective scheduling function model with the minimum variance of the remaining load process and the maximum energy storage at the end of the scheduling period is established by considering the peak regulation benefit of hydropower and the future benefit of the reservoir.The proposed model is solved by the NSAG-Ⅱ,and the non-dominated solution sets of different typical days are obtained.The results show that the coordination between the peaking capacity of hydropower and the future power generation income can be realized by the model,and the proposed scheduling scheme can ensure the power generation efficiency and the final energy storage simultaneously,and the multi-objective response in the scheduling is satisfied.