The fault modeling and analysis method of renewable energy stations is the basis of fault characteristics and protection research in wind power and photovoltaic centralized grid connected areas. However, the widely used single machine equivalent model cannot accurately reflect the short-circuit current characteristics of the stations. Based on the fault characteristics of the permanent magnet wind turbine, the dq axis currents before and after the equivalence are reduced, and the analytical relationship between the short-circuit current error caused by the equivalence and the electrical quantity boundary of the unit is obtained. According to the required equivalence accuracy, the cluster boundary for establishing the multi-machine equivalent model is given to realize the multi machine modeling of the permanent magnet wind farm. A simulation model is built with a typical actual station topology as an example. The simulation results show that the fault current characteristics of the proposed model and the detailed model are basically the same, and its accuracy is greatly improved compared with the single machine equivalent model, which verifies the rationality of the clustering criterion proposed in this paper.