Large-scale wind power i ntegration weakens the inertia level of the electric power system and brings challenges to the frequency stability of the electric power system.It is urgent to accurately estimate the inertia level of the system to ensure its safe operation.Therefore，an equivalent inertia estimation method of an electric power system considering the virtual inertia of wind power is proposed.Firstly，the inertia response of the synchronous generator and wind turbine is analyzed，and the principle of system equivalent inertia estimation is explained.Secondly，the Box-Jenkins model is used to dynamically model the power generation device.Based on the active-frequency disturbance data at the connecting bus of the unit，the bias compensation recursive least squares algorithm with forgetting factors is used to identify the parameters in the model.On this basis，the inertia constants contained in the model parameters are extracted，and the equivalent inertia of the system is calculated.Finally，a simulation analysis is conducted using examples to verify the effectiveness of the proposed method.The simulation results show that the proposed method can accurately estimate the equivalent inertia of the system under different disturbance types and different wind power penetration rates.