| With the rapid development of modern economy, the worldwide environmentalpollution and energy saving is increasingly serious. The distributed generation technologyhas gained rapid development for its advantages like renewable energy and no pollution.More and more attention has been paid to the micro-grid which is the integration of theeffective form of distributed generation.However, due to the trend in the micro-grid has two-way flow and the short-circuitcurrent will be different in grid-connected and islanded mode of micro-grid, the traditionalprotection strategy and protection devices can’t operate properly for the two modes. Theresearch on micro-grid protection is all just started in domestic and international, but it didnot have an effective protection strategy. In this paper, on the basis of in-depth analysis ofthe fault characteristics of the micro-grid in the grid-connected and islanded mode, andthen studied the multi-level protection methods of the micro-grid, according to theoperating characteristics of the micro-grid, the establishment of a micro-grid simulationmodel has been proposed and the simulation of the proposed model has been take to verifythe theory. Primarily works as follows:Firstly, according to the structural characteristics of the micro-grid, different types ofdistributed generation apply to different control strategies. The master-slave controlmicro-grid model has been set up using the PSCAD simulation software under detailedanalysis of PQ control and V/f control strategies. Secondly, the port output characteristicsof the single DG’s fault is in-depth analyzed and the fault characteristic of the micro-gridat both grid-connected and islanding operations are also analyzed. Finally, the micro-gridmulti-level protection method is proposed, the single point, multi-point information andthe protection of the global amount of information are combined, by the simulation results,the correctness and effectiveness of the protection scheme is verified . |
PDF Full Text Request