| With the depletion of fossil energy and increasing environmental problems,it is imperative to build an energy system with a high proportion of renewable energy.However,the grid connection of high proportion renewable energy will make the source-load mismatch of the power system more prominent,which requires the energy supply system to have stronger energy regulation ability.The integrated energy system can realize the complementarity and efficient utilization of different forms of energy,and the energy storage of it plays an important role in improving the time distribution of energy.But there is multiple energy storage in the integrated energy system.How to coordinate and optimize the sizing of different energy storage to achieve the optimal balance of energy supply and demand is a problem to be solved.Based on this,this thesis studies the sizing of energy storage for regional integrated energy system.Firstly,according to the four parts of energy input,energy conversion,energy storage and energy output,this thesis constructs a regional integrated energy system model that considers electricity,heat,cold and hydrogen,and analyzes the working characteristics and operation constraints of the equipment in each part in detail.Among them,energy storage is a multiple energy storage system including electric energy storage,thermal energy storage,cold energy storage and hydrogen energy storage.Hydrogen energy storage is modeled as seasonal energy storage and other energy storage as short-term energy storage.Then,this thesis proposes an optimal sizing model of multiple energy storage system based on multiple typical days: a typical day characterizes the probability of occurrence in a type of scenario,so the relationship between the energy state level of seasonal energy storage in different typical days can be established.On this basis,with the investment cost of energy storage and the operating cost of the system as the optimization objectives,and the planning constraints of the energy storage and operation constraints of system as constraints,a multiple energy storage system planning-operation joint optimization model was established.At the same time,the Big-M method is used to convert the nonlinear constraints of the model into linear constraints and then model is solved based on Yalmip.Finally,the case study is carried out based on the typical days in four seasons of the whole year: the results of energy storage sizing,system operation and the amount of abandoned wind and solar are discussed and analyzed respectively,the correctness and effectiveness of this method are verified;and through sensitivity analysis,it is concluded that energy storage sizing should be adjusted flexibly based on the change of peak valley price difference and price of purchased gas.Based on the source-load mismatch in power system with a high proportion of renewable energy,this thesis proposes an optimal sizing model of multiple energy storage system,which can provide useful suggestions for the planning of energy storage sizing and the economical operation of the regional integrated energy system. |
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