Fault ride-through control of the wind farm integrated with VSC-HVDC

Wind farms integrated by VSC-HVDC should have fault ride-through (FRT) capability during the AC grid disturbances. This paper investigates the V-I characteristic of VSC-HVDC transmission system used for wind farms integration at first. Based on the analysis of wind turbines inertia, a novel FRT control strategy for the proposed VSC-HVDC system is discussed. When the DC voltage of VSC-HVDC suffers fluctuations, the proposed control strategy adjusts the wind farm frequency according to the DC voltage deviation. Moreover, the resulting imbalanced power is temporarily stored in the form of generator rotor kinetic energy so as to keep the system power balanced. This FRT control strategy is validated by the simulation studies using MATLAB/Simulink. With the proposed strategy, the wind farms integrated by VSC-HVDC can keep connection to the grid during the fault, thereby providing useful network support similar to a conventional power plant.