Consensus Protocol Based Distributed Hierarchical Control Of Multi-Microgrids

With the continuous improvement of power conversion technology and microgrid control technology,the scale and structure of microgrid presents a trend of high density and diversification.Adjacent microgrids can be combined into a multi-microgrid system,which further improves the renewable energy consumption capacity and power supply reliability.Economic benefits maximization is one of the crucial research fields in multi-microgrids.With the increase of controllable units,the operation mode of microgrid becomes more complexity and the operation data increases enormously,which makes the central controller of traditional centralized economic dispatch method approaches to its borderline rapidly.The system will be paralysed,if the central controller fails.Microgrid optimal dispatch can be realized by multi-agent based control algorithm in a distributed way,and obtains the data of an agent and its neighbors only.The multi-agent based distributed method is one of the vital means to get rid of centralized control dilemma.Current researches of incremental cost based distributed algorithm in microgrid mainly focuses on the control of controllable units,while the research on multi-microgrids economic dispatch regards single microgrid as a elementary unit.Economic dispatch studies considering both micro source and microgrid in multi-microgrids are rarely seen in published papers.This paper focuses on the equal incremental distributed control for multi-microgrids.Chapter 2 compares the similarities and differences between the consensus algorithm and group consensus algorithm in first-order discrete system.Chapter 3 and Chapter 4 analyze and simulate the incremental cost economic dispatch of single and multi-microgrids respectively.The main contents and contributions of this paper are summarized as follow:1)The consensus problem of multi-agent is discussed.The basic theoretical framework of the first-order discrete consensus protocol is analyzed,and the convergence speed and convergence effect of the system under different weight matrices are compared.The calculation method of the weight matrix which satisfies the demand is selected.The control concept under group consensus is introduced,and the convergence coefficient and consensus convergence of group consensus are studied.2)Equal incremental cost based distributed consensus control in single microgrid is studied.The distributed method is adopted to solve the single point fault problem. The 14-node microgrid which contains distributed generators,flexible loads and renewable generators is dispatched reasonaly via the first order discrete consensus protocol.Optimal economic operation of the system is achieved.3)Equal incremental cost based distributed consensus control for multi-microgrids is presented.Combined with the idea of hierarchical control,group consensus is adopted to solve the "global follow-up regulation effect" problem in the single microgrid distributed control.Different control objectives can be achieved in multi-microgrids under the control of the proposed method.The operation benefit of the system is guaranteed.