Electro-mechanical Transient Modeling and Simulating of MMC- HVDC for Offshore Wind Farms

Aiming at the stability analysis requirements of large power grid after being connected to offshore wind farm and flexible DC transmission system, the simulating models of offshore wind turbine, flexible DC, offshore wind farm and power grid are established by electro-mechanical transient simulating method. The grid side converters of offshore wind turbines and the flexible DC are both controlled by constant DC voltage control strategy. The outer loop control system of converters is modeled and converters are connected to the AC network in the form of controlled current source. VF control strategy is adopted for the farm side converters, which connects to the AC network in the form of Thevenin equivalent model, and the outer and inner loop control system are modeled. The proposed simulating model is established by DSP (Dynamic simulating platform) software, and the simulation results verify the effectiveness of the proposed modeling method.