Enhancing HVRT capability of DFIG-based wind farms using cooperative rotor-side SMES considering the blocking fault of LCC-HVDC system

Abstract

Line-commutated converter based high voltage direct current (LCC-HVDC) has been applied for transferring bulk power from wind farms to load centers through long distances in many countries. When the blocking fault of the LCC-HVDC system occurs, the surplus reactive power accumulated at the sending end will lead to an overvoltage, thus causing the disconnection of the wind turbines. To maintain the reliable connection of wind turbines and ensure the stability of the power system, this paper introduces a superconducting magnetic energy storage (SMES) unit to connect in parallel with the rotor side of the doubly fed induction generator (DFIG). By controlling the energy side converter and rotor side converter to inject demagnetizing current and reactive current into the rotor, the proposed scheme can effectively stabilize key parameters of the wind turbine and provide desirable reactive power support, showing a favorable high voltage ride through (HVRT) performance. Several cases based on PSCAD/EMTDC MATLAB/Simulink co-simulation together with economic analysis are conducted to demonstrate the feasibility and superiority of the proposed scheme on enhancing HVRT capability of DFIG-based wind farms.