Study On Coordinated Optimal Dispatching Of Multi-microgrids With CCHP

With the development of the combined cooling,heating and power(CCHP)system and the microgrid technology,more and more microgrids will be integrated into the power system.Those microgrids are clustered in a certain area and connected to each other tightly to form a multi-microgrids system.The economy of microgrid operation and energy utilization efficiency can be improved by the power exchange among microgrids and the coordination of the output of micro-sources in microgrid.This thesis studies the coordinated optimal dispatching of multi-microgrids with CCHP.The main contributions are as follows.The models of main components in microgrid with CCHP are given,including the model of gas turbine,chiller,air conditioner,boiler in CCHP system,and the model of DERs like photovoltaic and wind turbine,the model of energy storage system,the mode of ground source heat pump and chilled water thermal storage,etc.This lays the foundation of the modeling of optimal dispatching of multi-microgrids.The optimal dispatching model of multi-microgrids with single object considering the power exchange among microgrids and the coordination of the output of micro-sources is built.This model not only takes the power exchanges among microgrid and the ones between each microgrid and the distribution network into account,but also considers the influence of the interactive power between microgrids on the output of inner refrigeration and heating micro-sources in microgrid.The object is to minimize the total operation cost of multi-microgrids system.In a test system,the output of micro-sources in microgrids and the total operation costs of multi-microgrids are compared in two modes: the independent operation mode and the coordination mode for each microgrid in a multi-microgrids system.Test results show that the inner micro-sources of microgrids will be influenced in the case that the interactive power is under consideration,and the total operation cost of CCHP type regional multi-microgrids system will be reduced by the coordinated optimization of multi-microgrids,which shows the effectiveness and economy of the proposed model.A multi-objective optimal dispatching model for multi-microgrids with CCHP is proposed,which considers the combination of economy and energy efficiency.And the energy storage operation constraints and the output of gas turbine in the model are linearized to call CPLEX software to solve the problem.The multi-microgrids system with three microgrids in some place in Tianjin is tested.The test result shows the proposed method can improve economy of the multi-microgrids system on condition that ensuring the energy efficiency in a certain range.