Study On The Island Mircro-Grid Optimal Dispatching Based On Reconfiguration Theory

The development of distributed generation technology brings hope for the increasingly serious energy crisis in society.At the same time,Micro-grids are receiving attention due to the increasing need to integrate distributed generations and to ensure power quality and provide energy surety to the customers.And the micro-grid optimal dispatching as an important content of micro-gird technology has theory and project signality.The paper confronts the issue that we lack of an efficient way to achieve micro-grid optimal dispatching and proposes the structural reconfiguration and functional reconfiguration to achieve micro-grid optimal dispatching based on the reconfiguration theory.Then the proposed methods are applied in island micro-grid platform built in this paper.Firstly,the concept and research status of micro-grid and its optimal dispatching are introduced in this paper.Also the basic content of reconfiguration theory and concepts of structural reconfiguration and functional reconfiguration are expounded.In order to prove the active role of reconfiguration theory in island micro grid,this paper proposes an island micro-grid with various distributed generation,energy storage device and other key devices based on the improved IEEE-34 node test feeder system.The models of gas turbine generation system,wind generation system,photovoltaic generation system,energy storage system and loads are built based on the theory analysis for them.These models are proved by PSCAD/EMTDC.Secondly,the relationship between distributed generation output power and load power is researched in this paper.On the basis of analyzing the reconfiguration theory,three different control strategies for grid connected inverter are presented.The functional reconfiguration can be achieved according to the environment change for this multi-functional grid connected inverter.This kind of inverter can not only deliver the power generation of distributed generations to micro-grid,but also can perform as active power filter(APF)at point of common coupling(PCC)as well as can improve the efficiency of inverter and decrease the system investment.Thirdly,on the basis of analyzing the reconfiguration theory,the structural reconfiguration for the distributed generations(e.g.photovoltaic arrays,wave energy generators,etc)which connected multiple generation devices in series and parallel are presented.The distributed generations with structural reconfiguration can change the electrical connecting structure between multiple generation devices.Especially,improved solar photovoltaic arrays with proposed self-reconfigurable strategy in this paper can automatically configure itself according to the condition of each photovoltaic cell under the non uniform illumination condition.Finally,the functional reconfiguration(multi-functional grid connected inverter)and structural reconfiguration(photovoltaic arrays reconfiguration)are demonstrated with extensive PSCAD/EMTDC simulation studies respectively.Also,the research for the combination between multi-functional grid connected inverter and photovoltaic arrays reconfiguration are achieved in this paper.The simulation results verify the correctness and efficiency of proposed theory in this paper.