Based on the assumption that the input/output variables of all AC devices in the PV station are of fundamental frequency， a method to simulate the operation characteristics of PV station's power conversion and transmission system is proposed. Phasor analysis and controllable power source theory are applied in the proposed method. A model is developed consisting of PV arrays， power inverters with maximum power point tracking function， transformers and control system. Comparison results between the measurement data and simulation results from a real PV system validate the proposed model.