Size Optimization Of Microgrid Integrated With Flexible Load

With the development of micro-grid,the large-scale use of solar and wind energy and the high growth of load demand,it is of great significance to improve the utilization ratio of renewable energy and economy for a micro-grid system.As the development of micro-grid,realizing the interaction between supply and demand is one of effective ways to improve the utilization ratio of renewable energy and economy for a micro-grid system.Flexible load involved in dispatching is able to realize it efficiently.Compared with the rigid load,flexible load as a kind of source that is schedulable is flexible and variable.It can participate in the operation of the micro-grid actively by adjusting load demand and assist batteries to balance the power between renewable energy power supply and load demand.Therefore,in order to increase the access of renewable energy,reduce resource consumption and improve the utilization ratio of power assets,this paper considers the role of flexible load while studying the size optimization of micro-grid.The specific work of this paper is as follows:(1)Firstly,the research status of size optimization of micro-grid and flexible load at home and abroad is introduced.Based on the definition of flexible load and the characteristics of various flexible loads,the optimal dispatching model integrated with industrial,commercial and residential load is established.(2)Secondly,from the advantage of micro-grid,the complementarity of solar and wind on size optimization is studied.This paper takes the complementarity of solar and wind as the evaluation index and makes a quantitative analysis of its function.To solve the multiobjective function well,a dimensionless method based on the concept of unit value is proposed,so as to evaluate the feasibility about the investment project of micro-grid,thereby obtaining a better combination of wind turbines and solar cells.Results shows that make the best of the complementarity of solar and wind in time,the utilization ratio of renewable energy is improved while ensuring the power supply reliability and economy of the microgrid system.And it lays a foundation for subsequent research.(3)Finally,the size optimization of stand-alone and grid-connected micro-grid systems considering flexible loads are studied respectively.Considering the different on power interaction between the two types of micro-grid and main grid,different optimal energy management strategies with multi-type flexible loads are proposed which emphasizes based on the coordination of flexible load.Aiming to improve the economy and the utilization ratio of renewable energy at same time,a multi-objective size optimization model is established.Furthermore,the influence of flexible load on user satisfaction and the ability to eliminate the fluctuation of renewable energy are analyzed.Take the same region as the research object,the particle swarm optimization algorithm with dynamic weight is used to solve the problem.Results shows that flexible load involved in dispatching is able to improve the utilization ratio of renewable energy and economy for a micro-grid system,thereby improving the comprehensiveness of size optimization.And the participation satisfaction of users is improved as well by participating in a micro-grid operation,so as to realize the interaction between the supply and demand.