In order to deal with the micro-grid, which consist of Inverter distributed generations (DG), on the basis of the low-voltage protection, using part of ideological distance protection scheme’s thoughts, this paper proposed a low-voltage inverse-time protection scheme. Compared with the traditional protection,Under different short circuit fault conditions, the protection principle, operating characteristics, coordination between primary protection and backup protection were investigated, analysed the micro-gird which consists of rotary DGs,and the transition resistance and other special problem’s influences on the low-voltage Inverse-time protection scheme were also investigated, and proposed improved recommendations. In MATLAB/Simulink environment, built a micro-grid model which contained different control methods of distributed generation, and verified the protection scheme. The low-voltage Inverse-time protection has good performance under different operating conditions and high resistance to fault resistor, and is able to remove fault quickly.
