With the development of new power system construction, distribution network as an important part, its safe and stable operation is more important. In order to make the distribution network have self-identification, self-positioning and self-healing functions, it is necessary to study the decentralized autonomous technology of the distribution network, including the state assessment and fault location technology of distributed power supply. In this paper, the autonomous intelligent agent unit (IA) is designed based on digital twin technology, which has the functions of state assessment, fault location and isolation. Through IEEE33-node with distributed power supply and MA-PSO algorithm, the internal autonomy of IA is simulated and analyzed. The results show that the proposed scheme and algorithm are fast, accurate and referable.