A Comparative Study on the Adaptability of Different Motion Equation Models of DFIG-Based Wind Turbines for Power System Frequency Stability Analysis

Ensuring frequency security is of vital importance for power systems. As the penetration of renewable energy generation (REG) continues to increase, its impact on frequency stability cannot be neglected. The motion equation model is a suitable modeling method for REGs, which can derive a model with a structure similar to synchronous generators. However, when using the motion equation models for frequency dynamic analysis, only the impact paths related to active power disturbance are retained. Adding that there are different types of motion equation models, it is important to discuss which type is more appropriate. This paper takes the doubly fed induction generator-based wind turbine as an example; two types of motion equation models are first derived and verified. Then, by looking back at the assumptions of the average system frequency model, the adaptability of each model is judged. By comparing the frequency dynamics between different motion equation models and the electromagnetic transient model, the results indicate that the motion equation model employing active power and terminal voltage dynamics as input variables is more suitable for average frequency analysis. Lastly, by utilizing these models in a power system, the analysis is verified through MATLAB/Simulink R2021a.