Research On Energy Dispatching Optimization Of Multi-microgrid Based On Path Planning

Because of the continuous access of various distributed energy sources to the distribution network,the stability of the power system is affected to some extent.Multimicrogrid system is to connect multiple single microgrids to each other,and improve the utilization rate of distributed energy and the stability of power system through reasonable scheduling optimization method.Therefore,it is of great significance to study multi-microgrid technology.In the optimization of multi-microgrid energy dispatching,there are still some problems,such as relying on the distribution network to earn profits,ignoring the energy loss in the dispatching process and ignoring the environmental protection.In order to solve these problems,this work proposes a two-layer optimization strategy for energy dispatching optimization of grid-connected multi-microgrid systems.The main research contents are as follows:(1)The basic structure of multi-microgrid system is studied and the mathematical model of each distributed generation unit is established.Firstly,three basic structures of multimicrogrid system are introduced.Secondly,the working principles of photovoltaic power generation unit,wind power generation unit,micro gas turbine and battery energy storage system are analyzed,and the mathematical model is established.Finally,according to the power mutual economy relationship with the large power grid,the mathematical model of purchasing and selling electricity is established.(2)The traditional optimization algorithm of social spider is improved.This thesis introduces the background and principle of social spider optimization algorithm.Aiming at the problems of low accuracy and slow convergence of social spider optimization algorithm,the social spider optimization algorithm is improved by combining local search operators,and compared with the original social spider optimization algorithm and particle swarm optimization algorithm under the same microgrid parameters.The results show that the social spider algorithm combined with local search operators has better performance.(3)The off-grid multi-microgrid system energy scheduling optimization based on path planning is realized.Firstly,the energy dispatch optimization strategy of off-grid multimicrogrid system is introduced,and then the Newton-Raphson method is applied to calculate the energy loss on each line of the off-grid multi-microgrid system during energy dispatch,based on which the path with the lowest loss is found to complete the energy interaction between each microgrid,and then the maintenance cost of each distributed generation unit and the cost of abandoned wind,abandoned light and abandoned load are considered comprehensively,and the objective function of the lowest operating cost of each distributed generation unit in the system is set.The objective function is set to minimize the operating cost of off-grid multi-microgrid system,and the corresponding constraints are set to analyze the power output of each distributed generation unit in the system,and finally the off-grid islanded microgrid scheduling and off-grid multi-microgrid scheduling are compared and analyzed.The results show that the off-grid multi-microgrid scheduling considering path planning can reduce the cost of wind,light and load abandonment,and achieve energy saving and cost reduction.(4)The optimization of energy dispatching of grid-connected multi-microgrid system based on path planning is realized.Firstly,the optimization strategy of grid-connected multimicrogrid system energy dispatching is introduced,then the path planning method is combined with the total cost of the multi-microgrid system and the minimization of the total network loss in the energy dispatching process as the objective function,and the optimal value is solved according to the corresponding constraints,and finally the dispatching optimization results of the multi-microgrid system are compared and analyzed with the dispatching optimization results of the single microgrid.Through the verification of the scheduling optimization based on the IEEE-16 node multi-microgrid system,the results show that the multi-microgrid system has a greater advantage over the single microgrid in terms of both cost and network loss,and can save cost and reduce energy loss,in which the total network loss generated by the interaction with the large grid when the microgrid is individually scheduled for optimization is 9843 k W,and the total operation of the system The total network loss of the microgrid system is 9843 k W and the total operating cost of the system is 24267 k W,while the total network loss of the multi-microgrid system is 5901 k W and the total operating cost of the system is 14785 k W when the microgrid system is dispatched and optimized based on path planning.