A Comparative Study for an Overall Grid-Forming System of HVDC and Offshore Wind Farm to Emulate Conventional Power Plants

Abstract:
This paper's comparative study analyses three different operational strategies for a grid-forming HVDC system with a grid-forming offshore wind farm to replace conventional power plants. Comparing these strategies aims to determine an operational strategy that uses the energy stored in the rotational mass of the wind turbines to respond to onshore grid events. Similar to conventional power plants, this system should contribute to system services in the transmission grid. Simulations are used to prove that the energy stored in the rotational mass of the wind turbines is mainly utilized in response to onshore grid events. Moreover, a superordinated power control is introduced to keep the overall system connected in case of a mismatch between the active power setpoint of the onshore modular multilevel converter and the available energy in the wind.