Optimal Load Dispatch Of Microgrid Considering Supply And Demand Uncertainties In Energy Internet Environment

Traditional centralized energy supply has some inherent drawbacks such as high cost,high pollution emission,low efficiency,and it cannot meet the increasingly diverse,clean,flexible and personalized energy demand.In order to cope with the shortcomings of traditional centralized energy supply,microgrid,including renewable energy and energy storage unit,has developed rapidly in recent years.However,the development of energy Internet makes the microgrid system face more complex energy supply and demand environment.And microgrid system has more diverse energy supply and demand uncertainties.On the energy demand side,large-scale electric vehicles(EVs)will be connected to the microgrid,but disorderly charging of large-scale EVs will affect the stability of the microgrid.At the same time,users can participate in the interaction between supply and demand sides of microgrid through demand response(DR).On the energy supply side,electricity network,heat pipe network,natural gas pipe network and many other types of networks are interconnected.Electricity,cold,heat,gas,hydrogen and other energy resources will be flexibly transformed and efficiently stored.Thus,the energy system in the energy Internet environment presents the characteristics of multienergy complementary and high coupling.In addition,a high proportion of renewable energy on the energy supply side will continue to penetrate into the microgrid,and the randomness and volatility of output of renewable energy put forward higher requirements for load optimization of microgrid system.Thus,this thesis focuses on optimal load dispatch of microgrid considering the supply and demand uncertainties under different scenarios.The economic,efficient and stable operation of the microgrid system under the energy Internet environment is realized through the coordinated scheduling of the supplydemand side load resources and the effective treatment of the uncertainties.The specific research contents are as follows:(1)Research on optimal load dispatch of microgrid considering the charging/discharging uncertainty of demand-side EVs.To deal with the effect of uncoordinated access of large-scale EVs on the stability of microgrid,an optimal load dispatch model of microgrid considering stochastic access of EVs is proposed.Based on vehicle-to-grid(V2G)mode,EVs are treated as a kind of mobile distributed energy storage device to participate in the optimal load dispatch of the microgrid.The uncertainties of EVs are modeled by using the Monte Carlo simulation.The proposed model considers the operating cost,pollutant treatment cost and load variance of microgrid system,which can reduce the total cost and improve the stability of microgrid system.And an improved particle swarm optimization(PSO)algorithm is proposed to solve the proposed model effectively.(2)Research on optimal load dispatch of microgrid considering the uncertainty of supply-side renewable energy output.The development of energy Internet has laid a good foundation for the collection and analysis of energy data.Thus,a data-driven load optimization scheduling method is proposed in order to cope with the impact of the uncertainty of renewable energy output on the multi-energy microgrid load dispatch.We first construct a confidence set for the unknown distribution of the wind power by learning from the historical data.Then,a two-stage distributed robust optimization model is proposed,which can achieve a good compromise between the economy and robustness of microgrid system.To effectively solve the proposed two-stage distributed robust optimization model,the column and constraint generation algorithm(C&CG)is used to solve the problem.(3)Research on optimal load dispatch of microgrid considering interaction uncertainty of supply and demand side.The optimal load dispatch model of power,gas and heat complementary microgrid based on DR is proposed.The proposed model comprehensively considers the operation cost and CO2 emission cost of the microgrid system.At the same time,the proposed model considers the disordered access of EVs.In order to further improve the energy efficiency and reduce the operating cost of the microgrid,both the electrical and thermal DR programs are considered.Moreover,a robust optimization method is used to deal with the uncertainties of renewable energies and electricity prices on the optimal load dispatch model in the interaction between supply and demand sides of microgrid.The proposed model is a two-layer optimization model,which is transformed into a single-level mixed-integer linear programming(MILP)model according to the duality theory and linearization method.Then a commercial optimization solver is used to solve the problem.(4)Research on optimal collaborative operation of multiple microgrids considering interaction uncertainty of supply and demand side.The coordinated operation of multiple microgrids can further improve the reliability and reduce the total cost of the overall system through energy sharing.In order to realize the advantages of multi-microgrid interconnection,a novel multiple microgrids optimal load dispatch model is constructed.The proposed model considers the economic and environmental benefits of the multimicrogrid system.In addition,both the electrical and thermal DR programs are taken into account in order to further reduce the energy cost of the system.Moreover,a robust optimization approach is proposed to cope with the uncertainties of renewable energies and electricity prices in the multi-microgrid system.In summary,the problem of optimal load dispatch of microgrid is studied from the perspective of optimal load dispatch of microgrid considering the charging/discharging uncertainty of demand-side EVs,optimal load dispatch of microgrid considering the uncertainty of supply-side renewable energy output,optimal load dispatch of microgrid considering interaction uncertainty of supply and demand side,optimal collaborative operation of multiple microgrids considering interaction uncertainty of supply and demand side.The optimal load dispatch models of microgrid considering the supply and demand uncertainties under different scenarios are constructed.This thesis provides theoretical support for promoting the economic,efficient,green,low-carbon and safe and stable operation of microgrid in energy Internet environment.