Research On Decentralized Coordinated Dispatch Method Of Multi-microgrid Integrated Energy System

With the increasingly severe energy crisis and environmental pollution,the development of a clean,low-carbon,safe and efficient modern energy system has become a new trend.The integrated energy system(IES)can improve energy utilization efficiency and renewable energy consumption capacity,which has become a research hotspot in this field.The multi-microgrid integrated energy system(MMIES)is composed of the regional electric power distribution system(EPS)and natural gas distribution system(NGS),as well as multiple microgrids(MMGs)connected to EPS and NGS,which can effectively utilize resource endowments and energy supply-use characteristics of different microgrids,and improve the overall economy of MMIES.However,the power interaction between microgrids in MMIES,as well as the coupling operation of different stakeholders,and the inability to solve independently,will have a great impact on the optimal operation of microgrids and the safe and economic dispatch of distribution networks.Therefore,it is urgent to carry out research on the optimal dispatch of MMIES.The thesis focuses on the decentralized coordinated dispatch of MMIES.Firstly,a two-tier dispatch architecture of MMIES is proposed,and the power flow model of EPS and NGS and main equipment models of MMGs are established.Besides,regarding EPS,NGS and MMGs as different stakeholders,the coupling relationship of each stakeholder and its interest game behavior in energy trade are analyzed.Secondly,based on the architecture,a two-tier optimal dispatch model considering multi-energy collaborative interaction is established.This model includes the network tier and the microgrid tier.At the network tier,EPS and NGS supply energy to MMGs under the network security constraints;at the microgrid tier,microgrids are interconnected to share electricity and natural gas with each other,and form the microgrid operator(MGO)to conduct energy trade with EPS and NGS;EPS,NGS,and MGO participate in the interest game with the goal of maximizing their respective interests,and coordinate the power of network-microgrid tie line.Aiming at the source-load uncertainty in MMGs,fuzzy optimization theory is introduced to improve the microgrid-tier dispatch model.The forecast of wind/PV output and load are described by fuzzy parameters,and a fuzzy chance-constrained optimal dispatch model considering source-load uncertainty is established,then the fuzzy chance constraints are turned into their clear equivalent forms based on trapezoidal membership parameters.In order to cope with the problem that each stakeholder operates in a coupling manner and cannot be solved independently,which is caused by the power of network-microgrid tie line,the analytical target cascading(ATC)is used to decouple the tie-line power,and the ATC-based decentralized coordinated dispatch model is established.Accordingly,the two-tier optimal dispatch problems are reconstructed into upper and lower sub-problems,which can be modeled independently and solved collaboratively.Finally,the proposed method is simulated and verified with a calculation example.Numerical results show that the proposed method can realize the safe,economical and reliable operation of MMIES by taking into account the network security and the source-load uncertainty,comprehensively considering the interests of each stakeholder,and taking advantage of the multi-energy collaborative interaction between microgrids.