Research On The Optimal Configuration For Combined Cooling,Heating And Power-Based Microgrids

With the global energy crisis and environmental problems increasing,it is the consensus of the national government and the public to vigorously develop distributed generation and improve energy efficiency.As a small integrated energy system with multi-distributed generation and multi-energy supply,the combined cool,heat and power(CCHP)based micro-grid can realize energy cascade utilization and is one of the important development directions in the energy field.Driven by the new round of power system reform,more CCHP micro-grid access the active distribution network in the form of multi-microgrid.Multi-microgrid and active distribution network serve as different stakeholders in the economy and there is a game relationship in the scheduling,which makes the CCHP microgrid no longer dominated by autonomous optimization.It brings new challenges to the planning of the cogeneration microgrid.In under this background,it is not applicable to use the traditional optimal configuration of CCHP micro-grid to independently configure the capacity of multi-microgrid.Therefore,the multi-microgrid collaborative planning method considering the economic dispatching of multi-microgrid and the active distribution network has very important theoretical significance and engineering value.To this end,this paper studies the optimal configuration method of CCHP multi-microgrid under active distribution network.The main research contents are as follows:(1)Analyze the internal structure and operation principle of CCHP microgrid,and explain the definition of active distribution power system with combined cooling,heating and power-based microgrids and the operation control structure of the active distribution network.A mathematical model for energy production equipment,energy conversion equipment and energy storage equipment in CCHP microgrid is established.(2)Established an evaluation index system for the optimization of the configuration of the CCHP multi-grids from the aspects of economy,technology and environmental protection,to achieve a comprehensive evaluation of the configuration plan.It provides a reference of optimal objective of capacity configuration of CCHP microgrid.(3)The model of dispatchable region of microgrids is used to quantitatively describe the operating boundary of the microgrid.The problem of the configuration capacity and operating range of the microgrid under the static security constraints of the distribution network is analyzed.On this basis,the principle of optimal configuration considering dispatchable region of microgrids is proposed.By comparing the difference between the operation mode of traditional CCHP microgrid and active distribution power system with combined cooling,heating and power-based microgrids,the principle of optimal configuration considering the economic operation strategy is proposed.(4)Established a bi-level optimization model for the CCHP multi-microgrid capacity.The upper model aims at the optimal economic and environmental protection,and uses interval arithmetic to transform the model of dispatchable region of microgrids into the upper-layer model.On the basis of this,the lower model adopts the economic operation strategy to optimize the running curves of each type equipment in typical day.The bi-level model is solved by improved particle swarm combining CPLEX.(5)Taking the distribution system with distributed generation as an example,the proposed bi-level optimization model is used to optimize the capacity of CCHP multi-microgrid.The results show that the configuration scheme considering dispatchable region of microgrids and economic operation strategy avoids the mutual limitation of the multi-micro network operating domain and improves the economics of the configuration scheme.The optimal configuration principle and model proposed in this paper have certain reference value and guiding significance for the rational planning of the capacity allocation of the CCHP microgrid system under the active distribution network.