Study On The Switching Of Micro-grid Grid-connected And Autonomous Modes

As more and more attention has been paid to solar, wind, tidal, geothermal energy and other clean, cheap and pollution-free renewable energy's development and utilization, and in order to enhance energy security, reliability, economy and flexibility as well, the renewable energy based distributed generation technologies has been prompted. The key technology to rational and effective use of distributed power supply is these distributed power how to cooperation with bulk power grid, the safety and reliability of large power grid is influence by the large number of distributed power. Micro-grid as a distributed generation can play a very good potential forms of organization have been proposed, it's a distributed power supply and load as a whole, the formation of controllable, and can run the network also run a small island grid. Micro-grid as a high pressure, long distance, bulk power supply mode of the supplement, represents a new direction power system.This paper establish a micro-grid model based on inverter, according to the two modes of the micro-grid, the grid-connected and the autonomous modes, proposed control methods and strategies, mainly compares the PQ control,V/f control and droop control, and implement the islanding detection method in the model. Establish the small signal model of the two modes, analysis the stability of the parameters using eigenvalue, and focused on comparison eigenvalue distribution of variation before and after switching, accordingly proposed the switching control strategy.Finally, establish the model of micro-grid in MATLAB/simulink soft, and to achieve the switching of inverter's control strategy between the network and a small island grid, study on the dynamic characteristics of the run process independently, optimized on the switching controller, reduce the switching transient oscillation process. On this basis, summarise of the effects that various parameters on micro-grid impact on the smooth switching of the micro-grid, proposed solutions to. the situation can not be a smooth transition...