Enhanced Fault Ride-Through Method for Wind Farms Connected to the Grid Through VSC-Based HVDC Transmission

This paper describes a new control approach for secure fault-ride through of wind farms connected to the grid through a voltage source converter-based high voltage DC transmission. On fault occurrence in the high voltage grid, the proposed control initiates a controlled voltage drop in the wind farm grid to achieve a fast power reduction. In this way overvoltages in the DC transmission link can be avoided. It uses controlled demagnetization to achieve a fast voltage reduction without producing the typical generator short circuit currents and the related electrical and mechanical stress to the wind turbines and the converter. The method is compared to other recent FRT methods for HVDC systems and its superior performance is demonstrated by simulation results.