Voltage stabilization in connection of wind farms to transmission network using VSC-HVDC

This paper investigates possible improvements of grid voltage stability in connection of 40 MW wind farm to transmission network using VSC-HVDC. The 40 MW wind farm comprises 20 individual 2 MW permanent magnet synchronous generators. The voltage at the transmission network terminal should be re-established with minimized power losses during wind speed fluctuations and after the clearance of grid side short-circuit faults. This paper highlights a modified decoupling control strategy which is applied to VSC-HVDC converters to achieve variable speed operation and voltage stabilization in wind farm network and transmission network respectively. Simulations using PSCAD/EMTDC are performed to study behavior of wind farm, transmission network and dc link for various changes in wind speed and fault on ac grid. The simulation results validate the connection method and the modified decoupling control strategy.