| Wind power and photovoltaic power generation have the characteristics of randomness,volatility,and uncontrollability.Their large-scale grid connection will have a certain impact on the normal operation of the power grid,leading to a large number of wind and solar abandonment phenomena.By virtue of its heat storage system,the thermal power station can effectively cope with the negative impact of wind and solar uncertain output on the grid through "thermal energy throughput".In addition,the configuration of electric heater(EH)in the optical thermal power station can realize its two-way regulation with the grid,further solving the problem of wind and solar output uncertainty.Therefore,it is of great significance to combine the solar thermal power station with EH,wind power and photovoltaic power generation into the power grid,and study its operation optimization and capacity planning.The thesis mainly conducts research from the following aspects:Firstly,a wind power-photovoltaic-load uncertainty model and a solar thermal power plant output model are established,and their operation characteristics are analyzed.For the wind power-photovoltaic-load uncertainty model,model it through its corresponding probability density equation and distribution function;For the photo thermal power plant,through analyzing its operation mechanism,operation mode and energy loss in operation,a simplified energy flow model of the photo thermal power station is established,and the coupling mechanism with EH is analyzed.Secondly,with the goal of minimizing operating costs,a wind power –photovoltaic-solar thermal combined system operation optimization model with EH is constructed.At the solution level,it is transformed into a mixed integer linear programming problem through the linearization theory,and the improved IEEE-30 bus system is simulated and verified using the CPLEX solver.The results of the example show that the solar thermal power station with EH can effectively deal with the uncertainty of wind and solar output,improve the grid connection performance of the combined power generation system,and provide an operational basis for the study of the capacity planning of multi-source combined systems.Then,in order to ensure the universality of power capacity planning results,the uncertainty problem of wind power-photovoltaic-load was addressed through multi scenario analysis method.First,the Latin hypercube sampling method is used to construct the wind power-photovoltaic-load initial scenario set considering the correlation characteristics of the annual time series,and its uncertainty is expressed as annual scenario certainty.Then,the K-CFSFDP algorithm is used to reduce the initial scenario set to several typical scenarios,providing a prerequisite for studying the capacity planning problem of multi-source joint systems.Finally,based on the above operational optimization model and taking into account the uncertainty of wind power-photovoltaic-load,an annual equivalent investment cost for each power source is introduced to establish a capacity planning model for the wind power – photovoltaic-solar thermal joint system with EH.At the model solving level,the investment cost model(upper level)and the operating cost model(lower level)are linked using a bilevel programming algorithm.The upper and lower level models are solved using improved BFA algorithm and CPLEX solver,respectively.The example results show that reasonable planning of wind power,photovoltaic,solar thermal power station and EH capacity can further improve the grid connection performance of multi-source combined power generation system.The above work has certain significance in studying the optimization and capacity planning of joint grid connection operation of multiple power sources,and provides a theoretical basis for the investment and system operation plan of each power plant. |
