Optimal Operation Of Multi-Microgrid Integrated Energy System Based On Energy Flow And Carbon Flow Theory

Under the goal of green and efficient energy development,various renewable energy sources are vigorously developed,and the integrated energy system that can coordinate and optimize the dispatch of multiple energy sources,improve energy utilization efficiency and reduce carbon emissions has become a current research hotspot in the energy field.Multi-microgrid integrated energy system can further optimize the overall resource allocation,improve the renewable energy consumption rate and the economic efficiency of the system through the synergistic interaction and the complementary advantages of each microgrid.However,its diversified source inputs,loads and energy storage bring difficulties and challenges to the optimal operation of the whole system.Therefore,this paper investigates how to achieve low-carbon and economic operation of multi-microgrid integrated energy system by improving the utilization rate of renewable energy at the source side,optimizing the energy mutual aid among microgrids and the power deployment of multi-energy coupling devices within the network,and mobilizing the load-side low-carbon potential of users.(1)Firstly,systematic summary of the development and status of multimicrogrid integrated energy system and its economic and low-carbon operation is presented,and the hot spots and difficulties in the current research field are pointed out.Then,in the system modeling part,the integrated energy system is transformed into an energy hub based on graph theory,and the coupling matrix modeling method is used to model the energy hub systematically and sort out the energy flow relationship between each energy conversion module inside the system,so as to lay the foundation for the research on the optimal operation of the multi-microgrid integrated energy system.(2)Aiming at the operation of multi-microgrid integrated energy system,due to the waste of resources caused by the difference of renewable energy resources and energy demand of each park-type microgrid and the frequent interaction between regional distribution network and large grid electricity,this paper proposes a regional integrated energy system group optimal scheduling scheme combining power to gas and inter-park electric energy mutual aid.Firstly,for the park integrated energy system with different structures,the coupling matrix is used to describe the input-output relationship and coupling form of multiple energy sources in the energy hub,which linearizes the complex multienergy coupled system and is more conducive to the solution of the model.Secondly,the electrical coupling relationship of the system is improved by adding power to gas equipment to improve the system’s ability to consume renewable energy,and the impact of the installation cost of power to gas equipment on the economic efficiency of the system is considered comprehensively.Finally,with the objective of minimizing the network loss of energy flow,the optimal dispatching model of integrated energy system cluster with power to gas conversion is constructed through the electric energy mutual aid among the parks.The simulation results show that,compared with the independent operation of each park’s integrated energy system,the proposed regional integrated energy system group optimal dispatching strategy realizes the electric energy mutual aid among the park groups and reduces the dependence on the large power grid;it improves the renewable energy consumption rate and the utilization rate of power to gas equipment,reduces the energy purchase of the integrated energy system group,and improves the economy of the system group operation.(3)In order to reduce the carbon emissions of the system,this paper proposes an optimization operation strategy for the comprehensive energy system that considers carbon emission flow and low-carbon demand response.First,a system carbon flow model is constructed based on the theory of carbon emission flow,and the carbon emissions generated by source-side power generation are converted to the load end through power flow and various energy flow conditions,realizing the responsibility transfer of carbon emissions from the source side to the load end.Then,using the carbon emission density of each type of load as a signal,the low-carbon demand response strategy is used to guide customers to make energy use behaviors that reduce carbon emissions.Finally,the optimal economic low-carbon dispatching scheme is obtained by optimizing with the objective of minimizing the total cost of energy purchase and carbon emission of the system.The simulation results show that,compared to the traditional demand response strategy based on time-of-use electricity prices in the "electricity perspective," the low-carbon demand response strategy based on load carbon emission flow density in the "carbon perspective" has more advantages in achieving the low-carbon optimization objectives of the integrated energy system.