| At present,many renewable energy sources such as PV and wind power have many uncertainties due to the impact of the natural environment.These uncertainties have brought great challenges to the dispatching of traditional power grids,and also affected the gridconnected consumption of these renewable energy.In order to solve this problem,it has become a current research hotspot to combine multiple energy sources to generate electricity and use their complementary characteristics to optimize output,thereby improving power quality and energy utilization.Supported by the key research and development project of the Ministry of Science and Technology which title is research on distributed PV and cascade small hydropower complementary combined power generation,a cascade hydro-PV-pumped storage optimized power generation model is established through using the complementary characteristics of cascade hydropower and PV power generation in time and space,as well as the characteristics of energy storage and rapid adjustment of pumped storage unit.Moreover,research on the daily dispatch optimization method of the combined power generation system is carried out in this article.For the purpose,the complementary characteristics of water and solar and the regulation characteristics of pumped storage units is optimized,and the economic benefits,reliability and energy utilization rate of the cascaded hydro-PV-pumped storage hybrid generation system are improved.The main research contents of this paper are as follows:First of all,the current research status of multi-energy complementary dispatching at home and abroad are summarized,and the characteristics of cascade hydro-PV-pumped storage hybrid generation system and different multi-energy complementary optimization algorithms are analyzed.At the same time,the advantages and disadvantages of some commonly used optimization algorithms for multi-energy complementary scheduling are described.On this basis,the forecast errors of PV,runoff and load are considered comprehensively,and then the uncertainty models of PV,runoff and load are established.Then,considering the economy,loss of power supply probability,and water power utilization rate index of the combined power generation system,a multi-objective day-ahead optimal scheduling model of cascade hydroPV-pumped storage is established.At the same time,in order to refine the scheduling plan,with the generator set as the minimum scheduling unit,further considering the ramp rate constraint,start-stop constraint and vibration zone constraint of the hydropower units,the second-level optimal scheduling model is established.Then,in order to optimize the established dispatching model of the cascade hydro-PVpumped storage hybrid generation system,a multi-objective stochastic numerical P system optimization algorithm is proposed in this paper based on the multi-objective particle swarm optimization algorithm and the numerical P system algorithm.In the meantime,the three-layer nested membrane structure is given,and the function of each part is introduced in detail.Furthermore,a method of self-adjusting the number of iterations is proposed to reduce the number of unnecessary iterations in each membrane,and the feasibility of the proposed method is verified.In addition,in order to avoid the increase of computational complexity when the penalty function handles a large number of constraints,a correction method is added.Subsequently,for the second-level optimization model,the nonlinear constraints are linearized,and the mixed integer linear programming method is used to solve the model.Finally,using the data from the actual power plant in Xiaojin County,Sichuan province during the flood period and the dry period,simulation experiments and analysis of the proposed model are carried out.A comparative analysis between the proposed algorithm and several commonly used optimization algorithms in different scenarios proves the superiority of the proposed algorithm in terms of computing time and economic benefits.The experimental results show that:(1)The proposed optimization dispatching method can obtain stable and effective optimization results for the hybrid system under all the scenarios;(2)The addition of pumped storage units can reduce the frequent start-stop cost of cascade hydropower units and improve the economy of the hybrid generation system;(3)The uncertainty of PV and load will cause frequent dispatch of cascade hydropower stations,which will increase the start-stop cost of the system. |
