Abstract: Currently, the power system is in a critical period of energy transformation. A large amount of renewable energy is connected to the grid in the form of distributed power generation, which changes the original system structure of the distribution network and may cause the original pro-tection devices in the line to malfunction.Based on PSCAD/EMTDC simulation software, this paper conducts simulation research on fault characteristics and protection problems of distribution net-work with DG（Distributed Generation）. According to the influence of DG grid connection on the fault current of distribution network, propose an improved protection scheme for DG distribution networks. This scheme uses the phase angle change of the current on both sides as the criterion to locate the fault, which can ensure the correct operation of the protection device. Finally, the simulation experiment proves its feasibility. This scheme is applicable to the lines with power supply on both sides.