Dynamic Model Validation and Harmonic Stability Analysis of Offshore Wind Power Plants

With the increasing of wind power generation, it is of great importance to fully understand the small-signal performance of the wind power plants (WPPs). To deal with this issue, this paper developed an aggregate dq-frame impedance model for the large-scale offshore WPP, which capture the multiple timescale dynamic of the wind turbine (WT) converters. The long transmission cable is modeled by frequency scan and vector fitting method. Then, the impact of working point on the PLL, power control loop and voltage support are researched by the impedance-based small signal stability analysis, and it is shown that as the active power increase, the stability of offshore WPP will be more sensitive to PLL bandwidth but less sensitive to the voltage support parameters. The model and analysis are validated by PSCAD/EMTDC simulation.