The large-scale integration of wind farms leads to more complex stability modes. Online security and stability analysis is necessary to improve the new energy absorption capacity and operational efficiency of a power grid. An online calculation data generation technology is proposed to simulate the dynamic characteristics of wind farm accurately. First, the operating state of the low-voltage network is identified by the fusion of multi-source real-time data from state estimation, SCADA and security and stability control systems to form operating mode data integrated with wind farm clusters. A spatio-temporal correlation measurement correction model is adopted to identify and correct bad measurement data unhandled by state estimation. Secondly, a clustering method based on Analytic Hierarchy Process (AHP) is used to obtain a dynamic equivalent model of wind farm based on static characteristics and the operating state of wind turbines. Finally, the effectiveness of the method has been verified by cases of the actual power grid. This work is supported by the Key Research and Development Program of the Ningxia Hui Autonomous Region (No. 5229NX18001W).