Study On Optimal Operation Of Wind And Solar Power Generation System Based On Pumped Storage

In recent years,with the rapid development of the world economy and society,the world energy situation is increasingly tense.Renewable and pollution-free energy generation,such as wind power and photovoltaic power generation,has been greatly developed.But,wind power generation and photovoltaic power generation are greatly affected by geographical location and climate,so the power output is very unstable.Therefore,new energy generation systems are equipped with energy storage systems of suitable capacity.And the joint system of the effort to optimize the study is particularly necessary.In this case,the pumped storage system has shown its unique advantages,such as mature technology,fast start and stop speed and long service life.Therefore,this thesis uses pumped-storage system and wind-solar hybrid power supply system to form a combined generation system,and optimize the operation of the whole system.The study is divided into two parts,one is the study of the capacity allocation of pumped storage system for a given wind-solar hybrid power supply system,and the two is the optimal operation of the joint system.At present,there has not been an engineering example of combining the pumped storage system with the wind-solar hybrid power supply system,so it is the prerequisite for the optimal operation of the joint system to configure the multi capacity pumped storage system for the wind-solar hybrid power supply system.If the configuration capacity of the storage system is too small,the power fluctuation of the new energy system can not be suppressed fully;if the allocation capacity of the storage system is too large,it will cause waste.In this thesis,the optimal overall economy of the joint system and the minimum power fluctuation of the joint system are taken as the objective function,and the mathematical model is established considering the actual operation of each subsystem.Considering the randomness of the output of the new energy subsystem,the uncertainty of wind power and photovoltaic power is considered and reflected in the mathematical model.The improved particle swarm optimization(PSO)algorithm is used to solve the multi-objective problem.The installed capacity scheme of three kinds of storage systems is given for the established wind-solar hybrid power,and the power output fluctuation of the new energy system is verified by the three schemes.Considering the constraint condition of power output in the mathematical model of the combined system,when the pumped storage power station is built on the power supply side,the power output of the pumped storage power station will be limited by the transmission power of the power grid,and the regulating function of the pumped storage power plant will not be given full play.When the pumped storage power station is built on the load side,the transmission power of wind power and photovoltaic will be limited,and the phenomenon of abandoned wind and light will appear.Therefore,the economic simulation comparison of the location of the pumped storage power station on the power side and load side is carried out.On the basis of the front chapter,the optimization of the joint system is studied.Considering the impact of the joint system access to the entire power grid,a mathematical model of two levels of optimal operation is established.In the upper model,the joint system is equivalent to a power supply,which is connected to the regional power grid.The target power output curve of the joint system is given with the goal of the operation cost of the whole grid,the cost of cutting load and the lowest environmental cost.We let the optimization result of the above level model as a goal of the lower level model and optimize the output of the three subsystems in the joint system.Considering the correlation between the wind subsystem and the photovoltaic subsystem output,we analyze the wind and solar correlation in the combined system.Considering that the common method for joint probability distribution will be disturbed by many additional factors,the nonparametric kernel density estimation method is used to generate the joint probability density function.In view of the nonlinear characteristics of the research objects,two nonlinear coefficients,Spearman are used in the analysis of the correlation coefficients.According to the calculated nonlinear coefficient table between the subsystems and the load for 24 hours,the thesis is provided a reference for the optimization of the system.The effects of the joint system access on the discarding wind situation of large wind farms in the regional power grid and the output of conventional thermal power unit,as well as the effect of view correlation on the output of each subsystem in the joint system and the tracking target work rate curve of the joint system are analyzed.